SC) is a distinct type of cholangitis frequently associated with autoimmune pancreatitis and currently recognized as a biliary manifestation of IgG4‐related disease. Although clinical diagnostic criteria of IgG4‐SC were established in 2012, differential diagnosis from primary sclerosing cholangitis and cholangiocarcinoma is sometimes difficult. Furthermore, no practical guidelines for IgG4‐SC are available. Because the evidence level of most articles retrieved through searching the PubMed, Cochrane Library, and Igaku Chuo Zasshi databases was below C based on the systematic review evaluation system of clinical practice guidelines MINDS 2014, we developed consensus guidelines using the modified Delphi approach. Three committees  were organized. Eighteen clinical questions (CQs) with clinical statements were developed regarding diagnosis (14 CQs) and treatment (4 CQs). Recommendation levels for clinical statements were set using the modified Delphi approach. The guidelines explain methods for accurate diagnosis, and safe and appropriate treatment of IgG4‐SC.IgG4‐related sclerosing cholangitis (IgG4‐ IgG4‐related sclerosing cholangitis (IgG4‐SC) is a distinct type of cholangitis characterized by elevation of serum IgG4 levels, dense infiltration of IgG4‐positive plasma cells and lymphocytes, with fibrosis and obliterative phlebitis in the bile duct wall IgG4‐SC is diagnosed via a combination of imaging, serological, and histopathological findings, coexistence of other IgG4‐related diseases, and effectiveness of steroid therapy according to clinical diagnostic criteria of IgG4‐SC 2012 The guidelines describe currently accepted standard management but do not force medical action. Appropriate management of patients should be determined based on the situation of each institute and patient.A total of 234 and 2,340 publications published between 1991 and March 2017 were retrieved from a search of the PubMed database using the key words “IgG4‐related sclerosing cholangitis” and “autoimmune pancreatitis”, respectively. There was only one randomized controlled trial report, and the evidence level of the other publications was below grade C  n = 16], radiologist [n = 1], and pathologist [n = 2]), an expert panelist committee for rating statements according to the modified Delphi method , and an evaluation committee   and statements  and treatment (4 CQs) in consideration of PICO format, which described the population, intervention, control, and outcomes.http://www.tando.gr.jp/).Key words were extracted from the CQs, and academic papers were collected. A literature search was performed using the PubMed (MEDLINE), Cochrane Library, and Igaku Chuo Zasshi databases covering the period between 1995 and March 2017. Additionally, we searched the reference lists of articles identified by this search strategy and selected those that we judged to be relevant. Review articles and book chapters are cited to provide readers with more details and references. The search formula for each CQ will be available at the homepage of the Japan Biliary Association  (recommendation 1) or low (weak) (recommendation 2), as determined according to the following factors: quality of the evidence, patient's preferences, benefits and harms (risks), and cost. A recommendation was applied when more than 70% of the expert specialists (Delphi method) agreed. The use of “We recommend—” was adopted as the style for a strong recommendation. “We suggest—” was adopted as the style for a weak recommendation.The revised draft after the modified Delphi approach was evaluated by the evaluation committee using AGREE II IgG4‐SC is SC induced via an autoimmune mechanism and responds dramatically to steroid therapy. Most cases are associated with systemic IgG4‐related diseases such as AIP.Comment: IgG4‐SC is SC that responds dramatically to steroid therapy, with good clinical prognosis. Differential diagnosis from PSC, cholangiocarcinoma, pancreatic cancer, and secondary SC is necessary because these conditions show similar cholangiograms to IgG4‐SC. IgG4‐SC is a biliary manifestation of IgG4‐related diseases because it is associated with systemic IgG4‐related diseases such as AIP Since the 1970s, cases of SC associated with chronic pancreatitis have been published overseas and in Japan. In most of these reports, pancreatic disease was diagnosed as chronic pancreatitis and biliary disease as PSC. Waldram et al. reported two SC cases associated with chronic pancreatitis, diabetes and Sjögren syndrome in 1975 In 1991, Kawaguchi et al. reported lymphoplasmacytic sclerosing pancreatitis with cholangitis as a variant of PSC in Japan by studying surgical specimens st International Symposium on IgG4‐related disease, with establishment of uniform international nomenclature and pathologic characteristics of IgG4‐related disease The term “IgG4‐associated sclerosing cholangitis” has also been used Classifications based on cholangiograms and the association with AIP have been used.Inclusion of type 1 IgG4‐SC into the IgG4‐SC category has been disputed.Comment: Cholangiographic classification, which is useful for differential diagnosis, is the prevailing method IgG4‐SC is also classified based on the presence or absence of association with AIP. IgG4‐SC is frequently associated with AIP. When IgG4‐SC is not associated with AIP, this is referred to as “isolated IgG4‐SC” The stricture of the lower bile duct is caused by compression due to AIP The frequency of IgG4‐SC increases when type 1 IgG4‐SC is included in the IgG4‐SC category in epidemiologic surveys.In the international consensus diagnostic criteria, IgG4‐SC with extrapancreatic stenosis is regarded as additional organ involvement, which is useful in the diagnosis of AIP Inclusion of the type 1 disease in the IgG4‐SC categories has been disputed. Some researchers claim that the type 1 disease should not be classified as IgG4‐SC for the following reasons:Pathologic examination of the bile duct wall obtained from surgically resected samples showed abundant infiltration of IgG4‐positive plasma cells, storiform fibrosis, and obstructive phlebitis, which are characteristics of IgG4‐SC inflammation Thickening of the bile duct wall is observed continuously from the intrapancreatic to extrapancreatic bile ducts Isolated type 1 IgG4‐SC exhibiting no AIP findings has been reported By contrast, others claim that type 1 IgG4‐SC should be included as a class of IgG4‐SC for the following reasons:Indeed, it is difficult to identify the major factor contributing to the thickening of the bile duct wall – inflammation of the bile duct or compression due to AIP. Comments on diagnostic criteria of IgG4‐SC based on working group debates indicate that most cases of IgG4‐SC associated with AIP exhibit stricture of the lower bile duct caused by both thickening of the bile duct wall itself and pancreatic inflammation and edema SC is classified as PSC, IgG4‐SC, or secondary SC according to the disease concept and clinical features. PSC is an idiopathic, progressive, and chronic intrahepatic cholestasis caused by fibrous stenosis of the intrahepatic and extrahepatic bile ducts and does not respond to steroid therapy, whereas IgG4‐SC does respond to steroid therapy. PSC is positioned different from secondary SC, which should be treated etiologically.Comment: SC is classified as PSC, IgG4‐SC, or secondary SC according to the disease concept and clinical features. PSC is an idiopathic, progressive, chronic intrahepatic cholestasis caused by fibrous stenosis of the intrahepatic and extrahepatic bile ducts. To correctly diagnose PSC, IgG4‐SC and secondary SC must be ruled out IgG4‐SC has been reported in patients over age 60 years most commonly in association with an increase in serum IgG4 levels, whereas two peaks in age distribution were clearly observed in PSC patients with an approximately 10% increase in serum IgG4 levels Pathologic characteristics of PSC include fibrous obliterative cholangitis, so‐called “onion‐skin lesions,” whereas IgG4‐positive plasma cells infiltrate the portal area in IgG4‐SC It is necessary to rule out the following features of secondary SC with obvious pathogenesis, including infection, cholangiocarcinomas, previous surgery or trauma involving the biliary tract, common bile duct stones and chronic inflammation, congenital biliary anatomic defects, corrosive cholangitis, ischemic bile duct stenosis, AIDS‐related cholangitis, and biliary injury caused by intra‐arterial chemotherapy In intrahepatic and extrahepatic large bile ducts, transmural marked lymphoplasmacytic infiltration and fibrosis are observed, which give rise to bile duct wall thickening. Notably, storiform fibrosis and obliterative phlebitis are important histologic findings for diagnosing IgG4‐SC.An increase in IgG4‐positive cells is characteristic but not specific; thus, a diagnosis of IgG4‐SC needs to be established based on histologic findings.Comment: IgG4‐SC primarily involves the intrahepatic and extrahepatic large bile ducts and is characterized by transmural marked lymphoplasmacytic infiltration and fibrosis, which gives rise to duct wall thickening  and one case involving liver transplantation in the United Kingdom. In Japan, only four cases (two cholangiocarcinoma and two hepatic failure) were recorded, accounting for 0.8%, which was lower than the United States and United Kingdom rates P = 0.02). However, cancer‐related mortality was not increased compared with the national studies ; whether mortality is increased (and its cause if so) in patients with IgG4‐SC remains to be elucidated.In the United Kingdom report, the risk of all‐cause death was increased compared with matched national statistics  and thus should be differentiated from pancreatic cancer and cholangiocarcinoma. Type 2 IgG4‐SC, in which stenosis is diffusely distributed throughout the intrahepatic and extrahepatic bile ducts, should be differentiated from PSC. Type 3 IgG4‐SC is characterized by stenosis in the hilar hepatic lesions and lower bile duct. Type 4 IgG4‐SC presents with strictures of the bile duct only in the hilar hepatic lesions. The cholangiographic findings of types 3 and 4 IgG4‐SC should be discriminated from those of cholangiocarcinoma Fig. .In the diagnosis of type 1 IgG4‐SC, pancreatic cancer should be ruled out by endoscopic ultrasonography‐guided fine‐needle aspiration (EUS‐FNA) when the pancreatic mass of pancreas head is detected. Then, cholangiocarcinoma should be ruled out by bile duct biopsy under ERC. When IDUS and/or biopsy of the ampulla of Vater shows characteristic findings for IgG4‐SC, steroid trial is suggested. If these examinations do not show characteristic findings or steroid trial is not effective, re‐evaluation or surgical operation is selected. Surgical operation is indicated when malignant cells are detected or malignant diseases cannot be ruled out after careful re‐evaluation Fig. .In the diagnosis of type 2 IgG4‐SC, when characteristic cholangiogram is obtained, steroid trial is suggested. If combination of IDUS, peroral cholangioscopy (POCS), bile duct biopsy and biopsy of the ampulla of Vater reveals characteristic findings for IgG4‐SC in cases without characteristic cholangiogram, steroid trial is also suggested. If these examinations do not show characteristic findings or steroid trial is not effective, other sclerosing cholangitis or cholangiocarcinoma should be considered Fig. .In the diagnosis of types 3 and 4 IgG4‐SC, cholangiocarcinoma should be ruled out by bile duct biopsy under ERC. If malignant cells are not detected and IDUS, POCS and/or biopsy of the ampullary of Vater shows characteristic findings for IgG4‐SC, steroid trial is suggested. If these examinations do not show characteristic findings or steroid trial is not effective, re‐evaluation or surgical operation is selected. Surgical operation is indicated when malignant cells are detected or malignant diseases cannot be ruled out after careful re‐evaluation Fig. .Imaging reflects the characteristic pathologic findings, such as submucosal inflammation with little change in the epithelium and wall thickening diffusely spreading to non‐stenotic bile ducts in cholangiograms. In addition, these findings are dramatically improved with steroid therapy.Two aspects should be evaluated: distribution and character of stenosis, and wall thickness.Ruling out malignant diseases using biopsy and cytology under ERC is necessary in localized stenosis.Evaluation of cholangiographic differences is necessary in diffuse stenosis.Diffuse wall thickening with preserved epithelium in stenotic and non‐stenotic lesions is a characteristic finding for IgG4‐SC.Oral prednisolone at 0.6 mg/kg/day is recommended for initial remission induction therapy, with gradual reduction to a maintenance dose of 5 mg/day by 2–3 months. Maintenance dose should be continued for at least 3 years.Patients with comfortable radiological and serological improvement can stop steroids. After treatment is discontinued, patients should be followed up for relapse.We recommend that diagnosis of IgG4‐SC be based on the following four criteria: characteristic biliary imaging findings, elevation of serum IgG4 levels, coexistence of IgG4‐related diseases, except those of the biliary tract, and characteristic histopathologic features .In a specialized facility in which detailed examinations such as endoscopic biliary biopsy and EUS‐FNA can be performed, we suggest evaluating the effectiveness of steroid therapy as an optional extra diagnostic criterion to confirm a diagnosis of IgG4‐SC after negative work‐up for malignancy .Comment: As IgG4‐SC exhibits various cholangiographic features similar to those of PSC, pancreatic cancer, and cholangiocarcinoma, the differential diagnosis of IgG4‐SC from these three progressive or malignant diseases is very important.Two sets of diagnostic criteria for IgG4‐SC have been proposed. The HISORt  criteria were originally developed for AIP and adapted for IgG4‐SC IgG4‐SC is frequently associated with AIP It should be noted that an elevated serum IgG4 level is also observed in conditions such as atopic dermatitis, pemphigus, and asthma; in particular, elevated serum IgG4 levels are observed in PSC and some malignant cholangiopancreatic diseases (e.g. pancreatic cancer and cholangiocarcinoma) IgG4‐SC with strictures of the bile duct in the hilar hepatic lesions must be discriminated from hilar cholangiocarcinoma. In these cases, endoscopic procedures such as endoscopic ultrasonography (EUS), IDUS, cytologic examination, and/or biopsy of the bile duct are useful for correct diagnosis We recommend an examination of serum IgG4 levels for the diagnosis of IgG4‐SC .We suggest an examination of serum IgG4 levels for differential diagnosis from cholangiocarcinoma .We suggest an examination of serum IgG4 levels for differential diagnosis from PSC .Comment: An elevation of serum IgG4 levels is seen in 90% of IgG4‐SC cases An elevation of serum IgG4 levels is also seen in 9–22% of PSC cases Serum IgG4 has been assayed by two world‐wide systems, Binding‐Site system An elevation of serum IgG4 levels is seen in most cases of IgG4‐SC, so it is useful for the diagnosis of IgG4‐SC. However, an elevation of serum IgG4 levels is not specific for the diagnosis of IgG4‐SC. Cholangiocarcinoma and PSC cannot be excluded solely based on an elevation of serum IgG4 levels.We suggest ultrasonography for diagnosis of IgG4‐SC .We suggest EUS for differential diagnosis from cholangiocarcinoma .Comment: Only a few reports have described ultrasonographic findings for IgG4‐SC Ultrasonography can detect wall thickening from the intrahepatic to extrahepatic bile ducts but cannot detect wall thickening of the intrapancreatic bile duct. It is difficult to distinguish IgG4‐SC from PSC or cholangiocarcinoma using only ultrasonography. Nakamura et al. reported that the characteristic ultrasonographic findings of PSC include a homogeneous, high‐low‐high echo of the bile duct wall thickening, and in cases of severe wall thickening, the lumen of the bile duct becomes indistinct Ultrasonography is a useful modality for detecting wall thickening of the bile duct in patients with IgG4‐SC. Furthermore, ultrasonography can detect pancreatic swelling at the same time in patients with AIP. As ultrasonography is non‐invasive, it is proposed for use in the diagnosis of IgG4‐SC.Few reports have described EUS findings of IgG4‐SC Naitoh et al. reported that thickened walls detected by ultrasonography, computed tomography (CT), EUS, and IDUS involve circular‐symmetrical thickening, smooth outer and inner margins, and homogeneous internal echo at the stenotic area of the bile duct In order to detect dilation or stenosis of bile ducts and obtain a complete image of the biliary system, we suggest contrast‐enhanced CT and MRI/magnetic resonance cholangiopancreatography (MRCP) .For differential diagnosis of PSC or cholangiocarcinoma, we suggest contrast‐enhanced CT and MRI/MRCP .Comment: CT and MRI enable objective detection of biliary abnormalities, including dilatation or wall thickening of bile ducts, and are considered useful for identifying bile duct lesions . We suggest consideration of these IgG4‐related lesions .Comment: Although there are not many reports describing analyses of a large number of patients with IgG4‐SC, the most frequent associated disease is AIP (87–92%) ERC shows diffuse or segmental stricture of the intrahepatic and/or extrahepatic bile ducts .ERC is useful for differentiation between IgG4‐SC and PSC .Comment: Biliary tract imaging in IgG4‐SC reveals diffuse or segmental stricture of the intrahepatic and/or extrahepatic bile ducts. Although MRCP provides useful information, stricture of the bile duct should be assessed by direct cholangiography (i.e. by ERC or percutaneous transhepatic cholangiography). In clinical practice, ERC is recommended as the most useful diagnostic imaging modality for diagnosing IgG4‐SC The characteristic features of IgG4‐SC can be classified into four types based on the region of strictures as revealed by cholangiography and differential diagnosis Fig.  refer t.The main cause of biliary strictures in IgG4‐SC is severe lymphoplasmacytic infiltration into the bile ducts in the long region, resulting in long strictures. The main cause of the biliary stricture in PSC, by comparison, is obliterative fibrosis, which results in short strictures and bile duct loss IgG4‐SC with localized bile duct stricture must be differentiated from cholangiocarcinoma. Cholangiography cannot be used to differentiate between the hilar hepatic strictures of type 3 Fig.  or type Endoscopic transpapillary bile duct biopsy is performed to rule out cholangiocarcinoma, but it is difficult to obtain sufficient biliary tract tissue to evaluate for the characteristic histologic findings of IgG4‐SC (i.e. storiform fibrosis and obliterative phlebitis). A commonly used cut‐off value for IgG4‐positive plasma cell infiltration is 10 cells per HPF. Reports of the sensitivity of transpapillary bile duct biopsy as a basis for making a diagnosis of IgG4‐SC have ranged from 18 to 88% We recommend determination of the serum IgG4 level, concomitant diseases, cholangiogram, bile duct wall findings of contrast‐enhanced CT or IDUS, mucosal findings of POCS, pathologic findings of biopsy or brush cytology, and clinical course for the differential diagnosis of IgG4‐SC from cholangiocarcinoma .Comment: The differential diagnosis of IgG4‐SC is often difficult. Cases involving types 1, 3, and 4 disease are difficult to distinguish from cholangiocarcinoma  was low Elevation in bile fluid IgG4 levels has been reported in cases of IgG4‐SC but not PSC and cholangiocarcinoma, with sensitivity and specificity values of 100% at a cut‐off level of 113 mg/dl Most reports regarding the differential diagnosis of IgG4‐SC and cholangiocarcinoma discussed in this section were characterized by small sample sizes and low evidence levels. A review of these reports suggests that IgG4‐SC should be distinguished from cholangiocarcinoma using a variety of methods because the diagnostic utility of each modality alone is insufficient.We recommend consideration of age of onset, serum IgG4 level, coexisting diseases, image findings of biliary trees, liver histology, responsiveness to steroid therapy, and clinical course to differentially diagnose IgG4‐SC from PSC .Comment: PSC is a chronic inflammatory liver disease with poor prognosis characterized by progressive fibrosis of intrahepatic and extrahepatic bile ducts terminally leading to liver failure via cholestatic cirrhosis PSC and IgG4‐SC exhibit clinical differences related to (1) age of onset, (2) serum IgG4 levels, (3) coexisting diseases, (4) image findings of biliary trees, (5) liver histology, (6) responsiveness to steroid therapy, and (7) clinical course  patients and the other in more elderly patients The serum IgG4 level is frequently elevated in IgG4‐SC but not in PSC. A multicenter survey in Japan demonstrated a diagnostic sensitivity for IgG4‐SC of 89.9% when a cut‐off value of 135 mg/dl was employed PSC is frequently accompanied by inflammatory bowel diseases such as ulcerative colitis, with a prevalence of 60–80% in Western countries Typical imaging findings of biliary trees in PSC include band‐like strictures, beaded appearance, pruned‐tree appearance, and diverticulum‐like outpouching Important liver histology findings in PSC include periductal onion‐skin fibrosis and fibrous obliterative cholangitis With regard to medical treatment, patients with IgG4‐SC are treated effectively with corticosteroids, whereas extensive evidence suggests there are no satisfactory agents for treating PSC. Although ursodeoxycholic acid is widely used in patients with PSC, guidelines in Western countries indicate that its clinical benefit is uncertain. In addition, high‐dose ursodeoxycholic acid reportedly has no beneficial effect We suggest performing bile duct biopsy for the diagnosis of IgG4‐SC .We suggest performing bile duct biopsy for differential diagnosis from cholangiocarcinoma .Comment: The diagnosis of IgG4‐SC warrants bile duct biopsy to differentiate it from other diseases, particularly cholangiocarcinoma. However, definitive diagnoses of IgG4‐SC by bile duct biopsy are sporadic. The histopathology of IgG4‐SC is characterized by diffuse lymphoplasmacytic infiltration extending from the bile duct mucosa to the serous membrane, storiform fibrosis, obstructive phlebitis, and eosinophilic infiltration, whereas the histopathology of the bile duct epithelium is often normal. In other words, histopathologically, a definitive diagnosis of IgG4‐SC by bile duct biopsy, requires the collection of samples containing the bile duct stroma. Ghazale et al. reported pathologic diagnosis of IgG4‐SC in 14 of 16 patients (88%) by bile duct biopsy When we observe localized stenosis, excluding cholangiocarcinoma is necessary. Refer to CQI‐7 for differential diagnosis from cholangiocarcinoma.Histopathology of endoscopic biopsy samples taken from the ampulla of Vater for IgG4‐immunostaining can be useful as a supplemental tool for the diagnosis of IgG4‐SC. We suggest this technique for use in cases involving a swollen ampulla associated with pancreatic head involvement due to AIP in particular .Comment: Supplemental endoscopic biopsy histopathology using IgG4‐immunostaining could contribute to the diagnosis of IgG4‐SC in cases in which the ampulla of Vater is swollen Features such as swollen ampulla and abundant infiltration of IgG4‐positive plasma cells are regarded as indicative of pancreatic head involvement associated with AIP rather than diagnostic of IgG4‐SC We suggest IDUS for the differential diagnosis from cholangiocarcinoma or PSC .Comment: Endoscopic transpapillary IDUS is a reliable procedure to obtain high‐resolution images of the bile duct wall after ERCP. IDUS is performed by inserting a small‐caliber ultrasonic probe into the bile duct. IDUS is widely used for evaluation of bile duct stones, differential diagnosis of indeterminate biliary strictures, and superficial spread of cholangiocarcinoma. IDUS should be performed before biliary drainage, as such drainage often causes mechanical inflammation of the bile duct. IDUS findings of IgG4‐SC include circular‐symmetrical wall thickening, smooth outer and inner margins, and homogeneous internal echo in the biliary stricture .Comment: Lesional tissues are obtained by liver biopsy in about 25% of IgG4‐SC cases The standard for increased IgG4‐positive cells in the liver biopsy is >10 cells per HPF in the clinical diagnostic criteria for IgG4‐SC In terms of distinguishing IgG4‐SC from PSC in a liver biopsy sample, advanced fibrosis corresponding to stages 3 and 4 would be observed only in PSC and not in IgG4‐SC Complications, such as severe pain, vasovagal syncope, and hemorrhage, occur infrequently after a liver biopsy.We suggest the use of POCS for differentiating between cholangiocarcinoma and PSC .Comment: The detailed structure of the surface of the bile duct mucous membrane can be macroscopically observed using POCS. When combined with narrow‐band imaging, observation of blood vessels using POCS is useful as a diagnostic aid We suggest that steroid trials should be carried out only by experts familiar with AIP and IgG4‐SC or in patients with diagnostically challenging cases of IgG4‐SC without AIP or other organ involvement only after exclusion of cholangiocarcinoma .The effectiveness of steroid trials for diagnosing IgG4‐SC should be assessed by confirming resolution of findings on bile duct images obtained using ERCP/MRCP after 1 or 2 weeks of steroid administration at a dose of 0.4–0.6 mg/kg. In the absence of amelioration, we suggest re‐evaluation, including resection of cases suspicious for cancer .Comment: There are no reports of randomized controlled steroid trials for the diagnosis for IgG4‐SC. Only one paper regarding AIP and a few case reports have been published Steroid trials would be appropriate for use by pancreatobiliary subspecialists in diagnostically challenging cases mimicking PSC and/or cholangiocarcinoma. Almost all cases of IgG4‐SC are associated with AIP, and cases that are not associated with AIP are often accompanied by involvement of other organs. These diagnostic clues could facilitate a correct diagnosis of IgG4‐SC without evaluation of histopathologic evidence in bile duct samples We recommend steroid therapy for almost all IgG4‐SC patients. Immediate steroid therapy should be considered for IgG4‐SC patients with obstructive jaundice, acute cholangitis, and symptomatic extrabiliary IgG4‐related diseases .Comment: Steroid therapy is recommended as the standard treatment for IgG4‐related disease According to the Japanese consensus guidelines for AIP, the indications for steroid therapy in AIP are the presence of symptoms  and the presence of symptomatic extrapancreatic lesions It was reported that jaundice in some IgG4‐SC cases without acute cholangitis can be safely treated and effectively managed with steroid therapy alone, without any need for biliary stenting Biliary stricture relapse has been reported in IgG4‐SC patients during steroid tapering or after withdrawal of steroid treatment, and development of new biliary strictures has been reported in untreated IgG4‐SC patients We suggest performing biliary drainage in cases involving obstructive jaundice due to biliary stenosis .Steroid therapy can be initiated without biliary drainage in cases involving mild jaundice without cholangitis in patients for whom the diagnosis is definite and pathologic approaches to the biliary stenosis are unnecessary .Comment: In IgG4‐SC, it is important to differentiate bile duct invasion by pancreatic cancer or lower bile duct cancer in cases involving stenosis of the lower bile duct and to differentiate from hilar cholangiocarcinoma in cases involving stenosis of the upper or hilar bile duct. Regarding differential diagnosis, ERCP and related procedures play an important role. Many IgG4‐SC patients undergo ERCP, IDUS, transpapillary bile duct biopsy, and/or bile cytology with/without brushing, with ultimate insertion of an endoscopic nasobiliary drainage tube or plastic stent to relieve cholestasis and prevent cholangitis in a single session On the other hand, in a study of 15 AIP patients, Bi et al. of the Mayo Clinic Iwasaki et al. The above data suggest that as IgG4‐SC improves rapidly with steroids, steroid therapy can be initiated without ERC or biliary drainage in cases involving mild jaundice without cholangitis in patients for whom the diagnosis is definite and pathologic approaches to the biliary stenosis are unnecessary, such as in cases of stenosis of the lower bile duct associated with elevated serum IgG4 levels and diffuse enlargement of the pancreas We suggest oral prednisolone at 0.6 mg/kg/day  for 2–4 weeks for initial remission‐induction therapy .We suggest that the dose of prednisolone is reduced by 5 mg every 1–2 weeks after induction of remission, while confirming the response to steroid therapy by laboratory tests and imaging studies , and then gradually tapered further to the maintenance level by 2–3 months .Although the recommended maintenance dose is 5 mg/day, adjusting the dose within the range of approximately 5 mg/day based on the patient's response is suggested .After remission has been maintained for 3 years, it is possible to consider further reducing or discontinuing steroid therapy, but we suggest that this should be done carefully because there is a high risk of relapse .We recommend periodic assessment of symptoms, analysis of objective findings such as jaundice, and biochemistry tests, serum IgG/IgG4 levels, and imaging findings after the initiation of steroid therapy as well as after discontinuation of therapy. Care should be taken to identify relapse, exclude malignancy, and control adverse reactions to steroid therapy while managing the clinical course of these patients .Comment:1) Initial remission inductionThere have been few studies on steroid therapy for IgG4‐SC. Steroid therapy is indicated for patients who have AIP with symptoms, jaundice, and bile duct involvement. The standard treatment schedule recommended by the Japanese clinical guidelines for AIP 2) Dose reduction after remission inductionAfter induction of remission, the response to steroids is confirmed by laboratory tests and imaging studies. Steroid therapy is continued, with the dose gradually being tapered if other diseases are excluded, including cholangiocarcinoma, pancreatic cancer, and PSC. If improvement is not achieved by steroid therapy and the possibility of another disease is considered to be high, it is necessary to promptly review the diagnosis. After induction of remission with steroid therapy, the standard method is to reduce the dose of prednisolone by 5 mg every 1–2 weeks until the maintenance dose (5–10 mg/day) is finally reached at 2–3 months after starting treatment. Since it has been reported that there is a risk of relapse of SC, the steroid dose should be reduced while regularly checking for recurrence by monitoring symptoms and signs, biochemistry data, IgG/IgG4 levels, and imaging findings . After prednisolone is reduced to 15 mg/day, the dose is reduced further at longer intervals in some cases 3) Maintenance therapyA randomized controlled trial of steroid maintenance therapy was performed in 49 Japanese patients with AIP after induction of remission to compare maintenance therapy (5–7.5 mg/day) between a group treated for 3 years and a group in which therapy was discontinued at 26 weeks. It was found that the relapse rate up to 3 years was 23.3% in the former group versus 57.9% in the latter, and the long‐term maintenance therapy group had a significantly lower risk of relapse, with no serious steroid‐related adverse events We recommend both re‐administration and increasing the dose of steroids for treating relapse in IgG4‐SC patients .Immunomodulatory drugs and rituximab are useful in some relapse cases. However, treatment with these drugs is not covered by the medical insurance system in Japan (level C).Comment: Relapse of IgG4‐SC is generally defined as a reappearance of symptoms after remission , with the development or aggravation of bile duct strictures, and/or other organ involvement  with abnormalities on imaging, and/or elevation of serum IgG4 levels Disease relapse occurs in 30–57% of IgG4‐SC patients either during maintenance steroid therapy or after the discontinuation of steroids, particularly in the first couple of years Both re‐administration and increasing the dose of steroids have been shown to be effective in treating relapse patients Rituximab, a monoclonal anti‐CD20 antibody leading to B‐cell depletion, is reportedly effective for treatment of IgG4‐SC resistant to steroid and immunomodulator therapy. According to the limited data available, disease response is obtained in 80–90% of IgG4‐SC patients, including many with difficult‐to‐treat disease In international consensus statements for the treatment of AIP, immunomodulatory drugs or rituximab is recommended for relapse AIP as steroid‐sparing agents. However, treatment with these drugs for IgG4‐related diseases including IgG4‐SC is not covered by the medical insurance system in Japan None declared.


The samples were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) to study their crystallinity, morphology, and thermal properties, respectively. The work systematically demonstrated the chemical structure of the porous materials. Moreover, the advantages and disadvantages of the preparation method and typical properties of the material were evaluated through a comparative analysis with other related research works.In this work, we reported the preparation and chemical analysis of novel polyhedral oligomeric silsesquioxane (POSS)-based porous materials, which were prepared according to Friedel-Crafts chloromethylation by using aluminum chloride as the catalyst and dichloromethane as the solvent. Through controlling the treatment solvent (water or methanol) and kinds of POSS, several materials with different morphologies were conveniently obtained. The chemical structure of porous materials was systematically characterized by Fourier-transform infrared (FTIR) spectra,  General2 [2 , sol-gel2 [2 ,15,16, a2 [2 ,18. In a2 [2  and poly2 [2 , is also2 capture and conversion [POSS is widely used in polymeric nanocomposite modification, e.g., POSS/polystyrene nanocomposites . POSS-banversion .7-POSS) and OPS as raw materials and anhydrous aluminum chloride (AlCl3) as a catalyst. According to the literature, this is a very direct, efficient, and simple method. This has stimulated our interest in continuing to explore relevant issues. Lots of reported works have not yet given the reader a systematic and intuitive image, especially for the chemical structures. Therefore, this study intends to enrich the family of POSS-based porous materials and systematically analyze the chemical structures. Moreover, through a comparison with previous reports, we hope to comprehensively grasp the advantages and disadvantages of this method.The functional group on the surface of the absorbents is one of the key factors for improving the separation efficiency, and scientists have made great efforts to obtain novel adsorbents with special functional groups which contain a high quality. Therefore, porous adsorption resins modified by special functional groups via the Friedel-Crafts reaction have high potential for applications in the separation and purification of natural products with crude extracts . At pres3), sodium hydrate (NaOH), methanol, and anhydrous dichloromethane (DCM) were used as received from Beijing Chemical Works . T7-POSS was synthesized according to our recent work [Phenyltrimethoxysilane  was used without further treatment. Aluminum chloride (AlClent work .Phenyltrimethoxysilane (10 g), tetrahydrofuran , distilled water (1.2 g), and NaOH (0.9 g) were placed in a three-necked flask equipped with a reflux condenser and a magnetic stirrer. The mixture was refluxed in an oil bath at 65 °C for 5 h and then cooled to 25 °C for an additional 15 h with stirring. Ethylic acid was dropped into the mixture and white gel was obtained. After 5 days, the precipitate was collected and washed with THF, acetone, and ethanol at least two times, respectively. The white crystals were then dried in a vacuum at 45 °C for 24 h to afford the products with a yield of 30%.3 (7.2 g), and 80 mL anhydrous DCM were mixed into the three-neck flask and stirred continuously for 20 h at 40 °C. After that, the active hydrogen source was added dropwise into the reaction system. We could obtain different samples via different post-processing steps, as shown in 7-POSS. Furthermore, in order to analyze the chemical structure, especially the existence of the Al element, H2SO4 (pH = 1) was used to treat sample A. Typically, sample A was impregnated in the H2SO4 solution for 20 h.POSS-based porous materials were prepared by the Friedel-Crafts chloromethylation reaction. Typically, OPS (1.5 g), AlCl13C NMR was obtained at 11 kHz and the corresponding 29Si NMR spectra at 5 KHz TGA. Thermogravimetric analysis (TGA) was performed by using a TG209  in N2 atmosphere. Samples (5 mg) were heated from 50 °C to 800 °C at a rate of 10 °C·min−1. Two parameters were determined: temperature calculated at 10% (TG 90%) of weight loss and temperature at the maximum degradation rate (Tmax). Scanning electron microscopy (SEM) was performed on a HITACHI S-4700 scanning electron microscope  equipped with a field emission gun, at 4–10 kV. X-ray diffraction (XRD) patterns were recorded on a Bruker diffractometer with Cu Kα (wavelength: 1.5406 Å) radiation . The surface chemical composition of the porous materials was determined by an ESCA Lab 250 X-ray photoelectron spectrometer  with an Al Ka X-ray source (1486.6 eV) at a constant record ratio of 40. The core-level signals were obtained at a photoelectron takeoff angle of 45° (with respect to the sample surface). The X-ray source was run at a reduced power of 150 W. Nitrogen sorption isotherm measurements were performed on a Quantachrome QuadraWin surface area analyzer . Before measurement, samples were degassed at 100 °C for 24 h. A sample of 100 mg and an ultra high purity (UHP)-grade nitrogen gas source were used in the nitrogen sorption measurements at 77.3 K. SBET was determined over a P/P0 range of 0.01 to 0.20. The pore size was calculated from the adsorption branch of the isotherm using the Barrett-Joyner-Halenda (BJH) method [total) were derived from nitrogen sorption isotherms at a relative pressure of P/P0 = 0.995.Fourier-transform infrared spectroscopy (FTIR) spectra for all samples were obtained using KBr pellets in a TENSOR 27 spectrometer . Solid-state NMR was detected on the AV300  at room temperature. Cross-polarization, magic spinning (CPMAS) ) method . Total p3). As time elapsed, the mixture turned red and then became dark. 7-POSS and OPS). The smaller particles of sample C . The terminal –OCH3 (peak c), Ph–CH2–OH (peak b), and Si–O–CH2– (peak d) were found at ~65 ppm, ~55 ppm, and ~75 ppm, respectively. For sample A and sample B, no obvious bubbles were formed at the initial stage of the reaction. A large amount of hydrogen chloride gas was released only after water or methanol was added. Under this strong acidic condition, the POSS cage was partially destroyed and generated Si–OH accordingly. For sample C, Si–OH already existed at the beginning, and the reaction involving active hydrogen persisted throughout the whole reaction process. Therefore, gases were generated throughout the whole reaction process. Combining the chemical structure of 13C NMR spectrum analysis with the mechanism of the Friedel-Crafts reaction, we speculate that there are elementary reactions  and siloxy (−95 ppm to −120 ppm) substituted POSS cages account for most of the data recorded [29Si NMR, we concluded that the structure of POSS was destroyed to some extent, namely, hydrolysis took place and provided an amount of terminal Si–OH on the surface of the materials, which agrees with the FTIR results. Furthermore, the existence of the Q-group indicates the cleavage of Si–Ph, ensuring silicon surrounded by four oxygen atoms, which is consistent with the report elsewhere [For recorded . In addirecorded ,35,36. Arecorded , respectlsewhere . The rel7-POSS and OPS) XPS spectra  of 1.91 eV, which was obtained from the analysis of the raw materials’  species, respectively. In comparison with the C(Ph) species, the increase in BE of Ph–CH2–OH and Ph–CH2–Ph is attributed to the decrease of core electrons. The related data are summarized in 2–Ph, which is consistent with the 13C NMR results. The related data are also summarized in The corresponding Al2p core-levels are also shown in 13C NMR, 29Si NMR, and XPS analysis, we can see the specific chemical structures of the porous materials . In addition to the above structure, a small number of Si–OCH2–Ph structures exist in sample C. Notably, T7-POSS-based porous materials formed the Q-group, which have higher contents than those of OPS-based porous materials.According to the XRD results, 2 at higher temperatures. The derivative thermogravimetry trace of OPS has been reported [95), which agrees well with our result. Comparing sample C with sample A, the better thermal property of OPS-based materials compared to T7-POSS based materials is mainly attributed to the lager particle size, which leads to great differences in both heat and mass transfer. Moreover, it should be noted that the degradation at ~200 °C in T7-POSS is probably due to the intramolecular or intermolecular dehydration. The thermogravimetric curves decrease from the beginning (sample A and sample C), which is possibly due to the continuous release of adsorbed water on the materials’ surface . The typical data are listed in The thermal stability of POSS and its porous materials were recorded by TGA . The OPSreported  to indicWe think that the HCl release is a typical drawback of the method. Due to the HCl release, a NaOH solution must be employed during synthesis to absorb the generated HCl. The HCl could cleave siloxane, which was also observed in previous POSS-based porous materials by some other reactions, e.g., Suzuki coupling , the Hec3 being used as the only catalyst). CS2 (being toxic), DMF (with a high boiling point), tetrahydrofuran, and trichloromethane were usually selected as the solvent before. However, DCM chosen in this work can act as both a solvent and reagent, which is in line with the atomic economy. In addition, the use of T7-POSS raw material and the novel solvent choice finally extended the members of POSS-based porous materials.We have listed the specific conditions required for the preparation of materials in a series of reports, including time, temperature, raw solvents, etc., in BET) of all the three samples is less than the value reported in the literature [BET, sample B > SBET, sample A > SBET, sample C, indicating that the higher the degree of hydrolysis POSS displays, the smaller the specific surface area. This may be attributed to the hydrolysis of POSS, which weakens the immobilization of rigid POSS molecules and leads to the collapse of internal voids. Therefore, OPS-based samples are higher than those of T7-POSS-based samples, and sample B is higher than that of sample A . In addition, sample C shows a remarkable porosity by SEM, but it has the smallest SBET. This indicates that the specific surface area of this kind of porous material mainly contributes to a mesoporous or microporous pore size. We can further infer that the SBET values of the three samples in this work are lower than the values in other literature, mainly because of the high degree of POSS hydrolysis and the small space gap of only one –CH2– bridge. Finally, based on this work and the comparative analysis of existing literature, we can give some suggestions for the preparation and design of POSS-based porous materials, as follows: (1) maintain the integrity of POSS rigid particles as far as possible, which shows that adding acid binding agents such as triethylamine is an effective method; (2) reduce the use of volatile and toxic solvents such as CS2; and (3) introduce rigid bridging structures with a suitable spatial configuration.Furthermore, we found that the specific surface area (Sterature ,37,39,407-POSS. The morphology and chemical structure of porous materials can be controlled by changing POSS types and post-treatment solvents. Through the analysis, we showed the chemical structure of the material, and pointed out the advantages and disadvantages of the material preparation method. Furthermore, the surfaces of the materials were shown to be reactive due to the Si-OH and can provide further functionalization. As produced, the materials described here could be used as adsorbents. Additionally, they possessed surface hydroxyl groups, which may attract much interest for practical applications, including catalysis [We have demonstrated a facile synthetic method to prepare inexpensive porous materials by OPS and Tatalysis . Finally


Concrete-filled square steel tube column (CFSSTC) joints are the most important parts of concrete-filled steel tube frame structures. It is of great significance to study the damage of CFSSTC joints under the seismic loads. In this paper, embedded piezoceramic transducers are used to monitor the damage of core concrete of CFSSTC joints under cyclic loading and surface-bonded piezoceramic disks are used to monitor the debonding damage of the steel tube and core concrete of two specimens. The damages of the joints under different loading levels and different loading cycles are evaluated by the received signal of the piezoceramic transducers. The experimental results show that the amplitude of the signal attenuates obviously with the appearance of damage in the joints, and the degree of attenuation increases with the development of the damage. The monitoring results from piezoceramic transducers are basically consistent with the hysteresis loops and skeleton curves of the CFSSTC joints during the cyclic loading. The effectiveness of the piezoceramic transducers are verified by the experimental results in structural health monitoring of the CFSSTC joint under cyclic loading. Concrete-filled steel tube structures are being widely applied in civil engineering ,2,3,4,5.In recent years, the use of smart aggregates for damage detection and structural monitoring for structures under dynamic loads is receiving increasing attention. Xu et al.  proposedThe damage research of structures under dynamic load is mainly focused on reinforced concrete structures, and there is less research on the damage of concrete-filled square steel tube column (CFSSTC) joints. The beam-column joints are the key part of the frame structures. It is important to study the damage of the structure under cyclic loading for the concrete-filled steel tube structure. Therefore, in this paper, two CFSSTC joints with installed piezoelectric transducers are fabricated. The smart aggregates are embedded in the core area of the joint and the piezoceramic disk transducer is bonded on the outer surface of the steel tube. The piezoceramically-enabled active sensing method is used to monitor the concrete damage and the steel tube debonding in the core area of the joint under low cyclic loading.Lead zirconate titanate (PZT), as a type of piezoceramic material, has the advantages of good linearity, fast response, low cost, and sensing and actuating capacities , and hasSchematic diagrams of monitoring the concrete core damages and the debonding damages based on piezoceramically-enabled active sensing approaches are presented in It should be noted that the energy attenuation highly depends on the severity of the cracks. Compared with other parameters such as ultrasonic velocity and the change of frequency range, the signal amplitude has better sensitivity to concrete crack damage, and the amplitude decreases with the increase of damage severity. Therefore, the signal’s amplitude can be used as the main characteristic parameter for damage monitoring. The amplitude normalization method is used to process the signals received by piezoelectric sensors to detect the damage severity. The damage index (DI) is selected as the evaluation value of the damage of the joint specimen and is defined by:Two specimen joints were fabricated, named JD1 and JD2, as shown in The pseudo-static test method is adopted in the experiment. First, the hinge support is fixed by the ground anchor bolt to avoid the overall slip during the subsequent loading process, and then the bottom end plate of the joint is fixed to the hinge support. The top of the column uses a 2000 KN jack to apply the axial force, and the jack is fixed on the rigid beam. A seismic load was applied to the beam ends on both sides using a 500 KN actuator, and the actuator was attached to the beam. Before the test, preloading along the axial direction was applied 0.15 P to stabilize the load and deformation of the specimen, and unloading. The schematic diagram of the loading device is shown in Before the test, the ABAQUS software was used to establish the joint specimen model and to load the model monotonously ,74. ThroIt must be noted that loading should be stopped if one of the following conditions is reached: (1) the weld of the steel beam in the core area of the joint is completely broken or severely buckled at the flange; (2) the lateral loading force of the specimen falls below 85% of the peak loading force. The damage phenomena of the two specimens are basically the same and JD-1 is taken as an example to describe the test phenomena. JD-1 showed the following experimental phenomena: the weld seam at the end of the beam and the external strengthened ring joint basically broke, the web plate closed to the steel tube was cracked, the concrete floor collapsed and the surface crack was basically through, the floor and the ring plate were basically separated. The hysteresis loops and skeleton curves of the two specimens are shown in The hysteretic loops and skeleton curves of the two specimens were analyzed, which revealed that the slope of the hysteretic loops and skeleton curves of the specimens are small at the initial stage of loading, and the loading and unloading curves of the specimens are basically coincided. Before the loading displacement is 24 mm, the specimens are in the elastic stage. Subsequently, the slope of the curves changes gradually, and the specimens enter the yielding stage. When the loading displacement is 32 mm, the load reaches the peak value, and then the load decreases with the increase of loading displacement. At the initial stage of loading, the cracking of the internal concrete is restrained because of the restraint of the external steel tube. With the increase of the loading displacement amplitude and the number of cycles, the external steel tube gradually yields, and the restraining effect of the steel tube on the inner concrete is decreasing too. The number of cracks in the concrete increases continuously, and the crack width increases continuously, which results in the gradually reduced concrete bearing capacity.In order to analyze the structural damage in the frequency domain, the time domain signal received by the sensors are subjected to a Fast Fourier Transform (FFT) to obtain the frequency domain plots. The frequency domain signals obtained by the sensors in JD-1 and JD-2 are shown in It can be concluded that the signal amplitude of the S1-S3 sensor combination is weaker than the S1-S2 one when the specimens are healthy, according to According to According to To carry out a more detailed and accurate analysis of the damage of the specimens, the normalized DIs of the signal amplitude of the test specimens are shown in At the end of the test, the outer wall of the steel tube in the core area of the joint specimen was removed to observe the concrete failure and the debonding damage between the core concrete and steel tube. As shown in The comparisons of normalized DI for different loading cycles of JD-1 and JD-2 are respectively plotted in The comparisons of normalized DI for different loading cycles of JD-1 and JD-2 are respectively plotted in In this paper, embedded piezoceramic transducers are used to monitor the concrete core damage of concrete-filled square steel tube column (CFSSTC) joints under cyclic loading, and, in addition, a surface-bonded piezoceramic disk is used to monitor the debonding damage of the steel tube and core concrete of the specimens. The experimental results show that at the elastic stage, the attenuation of sensor signal amplitude is not obvious; at the yielding stage, the increase of load makes the deformation of joint specimen develop continuously, and the significant attenuation of the received signal amplitude indicate that the core concrete and steel tube are obviously debonded. At the failure stage of the specimens, because of the damage to the steel beam, the load on the beam of the joint core zone is gradually weakened, and the attenuation of the signal amplitude tends to be stable between different cycles. Through the analysis of the signals, the damage indices (DIs) of the core concrete of the two joints are less than 60%, which indicates that the core concrete is not completely damaged; the DIs of the debonding damage of the two joints reach about 90%, which indicates that the debonding damage of the concrete and steel tube is serious. The results of the data monitored by the smart aggregates under the low-frequency cyclic loading are basically consistent with the results of the seismic experiment of the specimens. The experimental results verify the feasibility of the use of piezoceramic transducer-enabled active sensing for structural health monitoring of CFSSTC joints. Future work will extend the piezoceramic-based structural health monitoring method developed in this paper to monitoring the internal damage monitoring of concrete-filled steel tube structures subjected to impact loading. As another task for future research, we will develop a method to distinguish between tensile or compressive damages for the concrete core in a CFSSTC.


The results showed that calcium could greatly decrease the gasification reaction temperature of SL, and the gasification reaction rates of acid-treated SL catalysed by calcium were significantly higher than that catalysed by potassium. Kinetic analysis showed that the activation energy of the reaction catalysed by calcium was much lower than that catalysed by potassium, which was the reason for the higher catalytic activity of calcium. Fourier transform infrared characterization showed that, compared with acid-treated SL, the addition of K+/Ca2+ resulted in the significant weakening of C=O bond, and new peaks attributed to carboxylate species appeared. X-ray photoelectron spectroscopy results indicated that the numbers of C=O decreased after the metal ions were added, indicating the formation of metal–carboxylate complexes. Raman characterization showed that the ID1/IG values increased, suggesting more structural defects, which indicated that the reactivity of coal samples had a close relation with amorphous carbon structures. Ca2+ could interact with the carboxyl structure in lignite by both ionic forces and polycarboxylic coordination, while K+ interacted with carboxyl structure mainly via ionic forces.The CO The gasification process takes place at least above 500°C. Although the devolatilization process takes place at the first stage, the volatiles may not be completely removed during the gasification process especially when the gasification agents are insufficient [2), Boudouard reaction (reaction with CO2), and steam gasification (reaction with steam) [2O or CO2 is the rate-determining step. Comparatively, the reactivity of CO2 with char is much less than that with steam, especially at temperatures lower than 900°C. So Boudouard reaction is generally considered as the rate-determining step in the gasification process [Highly efficient and clean utilization of the low rank coals (LRCs) has attracted wide attention around the world due to the large reserves of LRCs. Catalytic gasification is an important way for the utilization of LRCs. Gasification is a thermal chemical process by which the solid fuels are converted to combustible gases in the presence of different gas atmosphere, including steam, oxygen or carbon dioxide. The coal gasification can be divided into three main steps: pyrolysis, volatile matter reforming, and char gasification, and the last step is considered to be the rate-controlling step because it is kinetically slower compared with the other two steps ,2. The p process . Increas process .2 gasification of coal, and thus adding metal salts as additives during CO2 gasification of coal has served as a hot topic in the field of coal conversion [2 gasification of coal or char are much more remarkable than those of calcium [Catalytic gasification is one of the most attractive options to achieve low-temperature gasification due to the high gasification reaction rate, the selectivity in reaction pathways, and the useful gas products . Moreovenversion –16. Potanversion –19. Calcnversion . The catnversion . To the  calcium –26. Only calcium ,28. The + or Ca2+ is to be investigated, and the possible mechanisms of the catalysing gasification reaction are attempted to be studied.Recently, our previous studies showed that the catalytic effects of calcium were superior to those of potassium on the gasification of Chinese Shengli lignite (SL) ,30. In t2.2.1.Lignite obtained from Shengli coalfield in Inner Mongolia of China was used as the raw material. The received SL samples contained 47.6% moisture, 7.70% ash, 17.3% volatiles and 27.4% fixed carbons. The sample was ground, sieved to the size fraction of 38–74 µm for further processing, and dried in nitrogen atmosphere at 105°C for 4 h.+. The solution was configured as the ratio of 1 g SL+ and 3 ml acid solution of HF (greater than 40%) and soaked for 12 h. The suspension was filtered and washed with distilled water until pH neutrality and then dried at 105°C for 4 h, denoted as SL++. The dried SL and SL++ were also prepared similar to SL+. According to the previous results [+ and SL++ are listed in The demineralized SL sample was obtained by leaching with hydrochloric acid. Approximately 100 g of SL was mixed with 1000 ml 18% hydrochloric acid aqueous solution and stirred for 12 h at room temperature. The resulting slurry was filtered by a vacuum filter, rinsed repeatedly with distilled water to remove the residue chloride ions, and dried in nitrogen atmosphere at 105°C for 4 h, designated as SL results , the pro+ and SL++ is similar [+ coal samples were used to investigate the catalytic effect of different metals during CO2 gasification. The dosages of all metal ions were 5 wt% of total coal sample. KOH and Ca(OH)2 were added to SL+ by the impregnation method, named as SL+-K and SL+-Ca.The reactivity of the gasification of SL similar . Therefo2.2.2 gasification reaction was evaluated in a CCG-2010 fixed-bed quartz reactor. 2 gasification.The CO2) at a flow rate of 110 ml min−1. The reactor was heated up from room temperature to 600°C at the heating rate of 15°C min−1, and up to 1000°C at 2°C min−1.The reaction system consists of a steam generator and a fixed-bed reactor that is made of stainless steel (8 × 350 mm). The reactor is heated by an electric furnace. For each experiment, 150 mg of coal sample was loaded in the central zone of the tubular reactor sandwiched by quartz wool and quartz sand in order to maintain homogeneous temperature. Pressure of the reactor was adjusted to 0.25 MPa by reactant gas  equipped with a thermal conductivity detector, and the sampling interval was 4 min.The produced gas passed through an ice–water trapper followed by a cooler maintained at −30°C to prevent steam and tar matters from entering into the gas chromatography analyser. The concentrations of HiF) of H2, CO, CO2 and CH4 are given by2, CO, CH4, CO2 and Ar respectively, and m0 (g) is the original carbon mass.The gas instantaneous release rates (X) and gasification rate (r) were calculated using the following equations:X is the conversion of the coal samples, t0 the start of gasification (min), tg the termination of gasification (min), t the reaction time (min) [The carbon conversion (me (min) .The catalytic efficiency index (EI) is also indicative of the catalytic performance. The EI of the doped metal is defined as follows:2.3.−1 by a Nicolet FTIR spectrometer NEXUS670, and the spectral resolution was 4 cm−1. The potassium bromide and coal samples were dried in an oven at 105°C for 4 h before the FTIR investigation. Through the KBr pellet technique, coal samples and KBr at 1 : 200 were ground together to a fine powder and mixed well.The Fourier transform infrared (FTIR) spectra of the samples were recorded in the range of 400–4000 cm−1. Raman analysis was performed by the method of baseline drift correction and Gaussian peak-differentiating fitting.Raman spectroscopy with a 532 nm laser was used to investigate chemical structural changes of different samples. Raman analysis was conducted at room temperature by a Thermo Fisher spectrometer equipped with a DXR detector. The spectra were collected in the range of 500–3500 cm−7 Pa. The calibration was performed using the main C1s peak at 284.6 eV.Surface composition of the samples was determined by X-ray photoelectron spectroscopy (XPS) with Al K-α radiation using a PHI-5400 spectrometer from America. The analysis area was 300 × 300 µm. The degree of vacuum was 3 × 103.3.1.2 gasification was performed in a fixed-bed reactor system. Figure 2a demonstrates that the carbon conversion of CO2 gasification reaction was enhanced with the increase of the temperature for all lignite samples. The rate of CO2 gasification reaction of each sample was very low and could be negligible at temperatures lower than 700°C. The CO2 gasification conversion of SL+ increased to 15% at 900°C, which was much lower than those of SL+-Ca and SL+-K. SL+-Ca was converted almost completely at 850°C, and the conversions of SL+-K and SL+ were 60% and 10%, respectively.The CO2 gasification are shown in figure 2b. The reactivity of the SL+ sample increased slowly with the increasing of the temperature from 600 to 1000°C, but the reactivity of the SL+-Ca and SL+-K samples increased much faster. The CO2 gasification reactivity and reaction rate of SL+-Ca increased significantly once the temperature was higher than 600°C and reached the maximum at 750°C. Relatively, the CO2 gasification reaction rate of SL+-K increased steadily from 600 to 760°C. The doped Ca2+ and K+ showed obvious catalytic effects on CO2 gasification of SL+, and the catalytic effect of Ca2+ was more obvious.The carbon conversion rates of CO2 gasification of lignite samples. It can be seen from figure 2c that the EI of SL+-Ca was extremely high from 650 to 800°C. The EI of SL+-K is relatively much lower at the same temperature range.EI is used as a useful parameter for evaluating the catalytic efficiency of doped metal for the CO2 gasification reaction of Shengli lignite. Calcium greatly improved the reactivity and reduced the reaction temperature windows. The added potassium had similar catalytic effect on the CO2 gasification reaction of SL+ with the inherent minerals. The catalytic effect of calcium on CO2 gasification reaction is superior to that of potassium.The above results indicated that calcium exhibited significant catalytic effect on the CO3.2.k is the reaction rate constant (min−1), and n is the reaction index. The Arrhenius equation can be expressed as follows:R is a gas constant (8.314 J mol−1 K−1), E is the activation energy (kJ mol−1), T is the gasification temperature (K) and A is a frequency factor (min−1).The rate of the gas–solid reaction in a chemical reaction can generally be expressed by the following equation (3.1) :3.1dxdtFrom equations (3.1) and (3.2), it can be concluded that:Ea and frequency factor A can be calculated from the linear fitting of The activation energy +-Ca, SL+-K, SL and SL+ corresponding to main reaction ranges are illustrated in A, activation energy Ea and linear correlation coefficients R2 of SL+-Ca, SL+-K, SL and SL+ are listed in 2 gasification activation energies of SL+-Ca, SL+-K, SL and SL+ were 115.6, 167.8, 157.9 and 218.4 kJ mol−1, respectively. The addition of calcium reduces the activation energy of CO2 gasification reaction by 102.8 and 57.7 kJ mol−1 compared to SL+ and SL, respectively, which might contribute to the significant catalytic effect of calcium on the gasification reaction. The addition of potassium reduced the activation energy of CO2 gasification reaction by 50.6 kJ mol−1 compared to that of SL+ and slightly higher than that of SL. The activation energy of CO2 gasification reaction of the SL sample was lower than that of SL+, which proved the catalytic effect of inherent minerals on the CO2 gasification of Shengli lignite.The linear fittings of 3.3.3.3.1.a.The interaction between calcium or potassium cations and the inherent oxygen functional group within the lignite samples was confirmed by infrared spectroscopy. The FTIR spectra of the four samples are compared in figure 4−1, which could be attributed to the –OH stretching vibration, and bands at 2923 cm−1 and 2848 cm−1 were resolved into stretching vibrations of aliphatic –CH, –CH2, and –CH3. A typical 400–2000 cm−1 band in the FTIR spectrum is shown in figure 4b. It may be confirmed that the wavenumbers lower than 950 cm−1 were mainly attributed to the inherent mineral aluminium and silicon component in the SL+ by comparison with SL++. The most significant difference of infrared spectra lies in 1250–1750 cm−1. The band at 1597 cm−1 could be assigned to the stretching vibration of C–O bonds in a carboxyl structure, which should be between the bands of C–O and C=O bonds, and could not be clearly distinguished, because they were usually shielded by the oxygen containing functional groups in LRC varieties [−1. The FTIR analyses of SL and SL+ samples demonstrated reversible conversion of the metal carboxylate groups to carboxyl groups by the acid treatment. The peak intensities of SL+ and SL++ were increased at 1700 cm−1. The addition of Ca2+ and K+ into SL+ leads to the decrease of the band intensity at the same position because –COOH was transformed into –COOM in the presence of metal ions and the C=O absorption peak was weakened [2+ and K+ resulted in significant changes of the original C=O due to the formation of metal–carboxylate complexes. The separation of the FTIR bands  with the different metal ion addition. ID1/IG can be used to characterize the surface defect degree in coal samples. With the increase of ID1/IG, the graphitization was reduced. The ratio of IG/Iall reflects the amount of polyaromatic structure in coal sample. The metal ions combined with the carboxyl groups in the aromatic structure of coal, which affected the stability of polycyclic aromatic hydrocarbons to a certain extent. Therefore, the ratio of IG/Iall gradually decreased, and SL+ has the maximum degree of graphitization. The greater the degree of graphitization, the fewer the defects and the more stable the structure. It can be deduced that the amount of defects increased due to the introduction of the metal ions, and the contents of graphite crystal structures decreased compared with SL+. The reactivity of the SL+ samples was improved by the addition of metal ions. Therefore, it could be postulated that the reactivity of coal samples had a close relation with amorphous carbon structures.3.3.3.+-Ca. The carbon in coal existed in four forms, as shown in +, which meant that adding calcium and potassium could lower the aromaticity. The content of C=O also decreased probably due to the formation of the –COOM structure after adding the metal ion, which was proved by the FTIR results. The increase of C–O and COO– might be mainly due to the addition of calcium and potassium cations. The combination of the metals and COO– functional group led to more disorder of the coal structure of the samples.The main C1s XPS spectrum was used to characterize the surface elemental composition of coals. 3.4.3), as well as metal ions coordinated with oxygen functional group [+ or Ca2+ and the carboxyl structure is shown in + interacted with the carboxyl structure in lignite in the form of ionic forces, while Ca2+ interacted with the lignite in the form of both ionic forces and polycarboxylic coordination. The different interaction forms led to different effects on the activation energy of the gasification reaction. The addition of K+ led to the decrease of the activation energy from 218.4 kJ mol−1 (SL+ sample) to 167.8 kJ mol−1, while the activation energy for Ca2+ added sample decreased to 115.6 kJ mol−1. It could be speculated that the lower activation energy for Ca2+ added samples contributed to the superior catalytic performance compared with K+ during CO2 gasification reaction.Lignite is well known to contain amounts of oxygen, and the basic structure of the coal unit includes the polycondensation of various aromatic rings ,47, singal group . These bal group –54. Base4.2 gasification process were investigated. It was proved that Ca2+ and K+ could significantly promote the CO2 gasification, and Ca2+ exhibited higher activity than potassium. Kinetic analysis indicated that the activation energies of SL+-Ca, SL+-K and SL+ samples were 115.6, 167.8 and 218.4 kJ mol−1, respectively. Detailed characterization showed that K+ interacted with the carboxyl structure in lignite mainly in the form of ionic forces, while Ca2+ interacted with the lignite in the form of both ionic forces and polycarboxylic coordination. It could be deduced that the different interaction forms of Ca2+ and K+ with the carboxyl structure in lignite led to the differences in activation energy, and finally resulted in the superior activity of Ca2+ compared with K+. It is believed that this result could be applied to all LRC with high oxygen functional group content, especially carboxyl structure.In summary, the gasification reactivity and the structure changes of different SL samples during CO


In order to economically and reasonably solve the problem of mineshaft support in complex geological conditions, the mechanical properties of high-performance steel-fiber-reinforced concrete (HPSFRC) and its application in mineshaft lining structures were investigated in this study. Firstly, the mix proportion of HPSFRC for the mineshaft lining structure was obtained through raw material selection and preparation testing. Then, a series of mechanical property tests were conducted. The test results showed that the compressive, flexural, and tensile strengths of HPSFRC were 9%, 71%, and 53% higher than that of ordinary concrete, respectively. The fracture toughness of HPSFRC was 75% higher than that of the ordinary concrete and the fracture energy of HPSFRC was 16 times that of the ordinary concrete. Finally, the model test results of the HPSFRC shaft lining structure showed that the crack resistance, toughness, and bearing capacity of the shaft lining structure had been significantly improved under a non-uniform confining load because of the replacement of ordinary concrete with HPSFRC. HPSFRC was proved to be an ideal material for mineshaft support structures under complex geological conditions. It is necessary to build vertical shafts in stratum for ventilation, transporting minerals, personnel, materials, and equipment in order to exploit underground mineral resources by the well method. In order to maintain wellbore stability and resist formation pressure, it is necessary to build a strong support structure around the wellbore. In the bedrock section, ordinary concrete or reinforced concrete shaft lining structures have been usually used. However, with the increase of mining depth of coal mines, the engineering geological conditions of the strata which are passed through by the wellbore become more complex ,2. EspecStudies of stress analysis and the failure mechanism of shaft lining structures show that the stress state is very complex in unstable strata such as a fault fracture zone, where the stress state changes with time and stress concentrations are serious. The shaft lining structure is obviously subjected to non-uniform ground pressure. The concrete frequently used in such structures is easily damaged because it not only bears compressive stress but also tension and shear stress. This hidden danger always threatens the operation of the shaft. Therefore, finding or developing new support materials should be an effective technical way to avoid damage to mineshaft lining structures under complex geological conditions.High-performance steel-fiber-reinforced concrete (HPSFRC) is a kind of composite material formed by adding a certain amount of steel fibers into a concrete matrix. Previous literature shows that tensile and shear strength of HPSFRC is 20%–70% and 20%–100% higher than that of ordinary concrete respectively ,6,7. It The main goal of this study was to verify the superiority of HPSFRC in shaft lining structure. Thus, it was necessary to obtain the mechanical properties and the fracture toughness of HPSFRC and ordinary concrete by mechanical properties tests of the materials. Then, HPSFRC and ordinary concrete model tests need to be carried out to prove the superiority of HPSFRC shaft lining.According to our extensive investigation, concrete with a standard cubic compressive strength of 60 MPa (C60) is usually used in the shaft lining structure of coal mines. The raw materials for the concrete specimens were obtained locally.2/kg was selected. Its initial setting time was 145 min and final setting time was 199 min. Its stability was qualified. Its 3-day compressive strength was 25.7 MPa, and its flexural strength was 4.6 MPa. Its 28-day compressive strength was 55.8 MPa and flexural strength was 7.3 MPa.Conch P.II 52.5 Portland cement with a specific surface area of 389 m3. Basalt gravel was selected as the coarse aggregate, with a particle size less than 25 mm and a saturated surface drying density of 2720 kg/m3. The gradation of sand and gravel are shown in Huaihe River sand was selected as the fine aggregate, with a fineness modulus of 2.9 and a saturated surface drying density of 2580 kg/mThe high-performance powder water reducing agent NF, produced by Anhui Huaihe Chemical Co., Ltd. in Huainan, China, was selected. The water reducing rate was greater than 30%.2/kg. The microsilicon powder produced by Shanxi Dongyi Ferroalloy Factory  was selected, which had a specific surface area greater than 18,000 m2/kg.The slag produced by Qingya Building Material Co., Ltd. in Hefei, China, was selected, which had a specific surface area greater than 350 mRC65/60BN Dramix steel fiber, produced by Bekaert Applied Materials Technology Co., Ltd. , was selected. The appearance of the steel fiber is shown in The mix proportion of benchmark concrete was obtained through an orthogonal test shown in . OrdinarThe mixing sequence of HPSFRC was as follows. Firstly, cement, aggregate, and admixture were dried in a concrete mixer for 2 min. Secondly, steel fibers were added and stirred for 2 min. Then, NF powder water reducer was dissolved in 60% water and poured into the mixer for 3 min. Finally, the remaining 40% of water was poured into the mixer and stirred for 3 min.We prepared four groups of specimens  for each test for comparison. Each group contained three specimens. The dimensions and shapes of the specimens for the different tests are shown in The specimens were poured and vibrated with an 80-type concrete shaking table until the slurry was discharged. Immediately after shaping, the surface was covered with impervious film. Then, the specimens were placed in a standard maintenance environment  for 24 h, then released from molds and put into a YH-40 standard maintenance box for 28 days.A 2000-kN universal testing machine  was used for compressive strength test, split tensile strength test, and wedge splitting strength test. A 1000-kN universal testing machine was used in flexural strength, and bending test. Load rate and displacement of platen were controlled and monitored by software. After all the specimens were removed from the standard maintenance box, they were wiped clean with a dry cloth, placed in the equipment, and corrected according to the requirements of the specifications. In each test, an anti-cracking net cover was installed around the testing machine to ensure safety .The loading rate of the compressive strength test was controlled between 0.8 and 1.0 MPa/s. When the specimen was close to failure and began to deform sharply, the throttle of the testing machine was stopped from adjusting until failure occurred.The loading rate of the flexural strength test was controlled between 0.08 and 0.10 MPa/s. The flexural test device was used to ensure that two equal loads could be simultaneously applied at three points of the specimen span.The loading rate of the split tensile strength test was controlled at 0.08 and 0.10 MPa/s. A circular arc pad and a pad strip were placed between the upper and lower pressing plate and the specimen.A small notch (20 mm deep) was cut at the bottom of the specimens of the bending test. The loading rate was controlled at 0.025 mm/min (rate of cylinder displacement). When the specimen was approaching failure, the loading speed was reduced appropriately.In the wedge splitting test, the device was first clamped into the precut wide slot of the specimen shown in . A clampThe Pansan Coal Mine belongs to the Anhui Huainan Mining Group. Its second auxiliary shaft lining structure is 8.0 m in internal diameter and 1004.2 m in depth. The structure passes through a fault fracture zone and two thick coal seams with gas outburst between 884 and 940 m depth. The rock mass in the fault zone is loose and fractured, and thick coal seams have to be drilled holes to extract gas. All of these would deteriorate the stress conditions of the shaft lining structure. As far as we know, several shaft lining structures have been damaged under similar engineering geological conditions. For the reasons above, the second auxiliary shaft lining structure of the Pansan Coal Mine was selected as the engineering background of the model test.Due to the high strength and large size of the prototype structure, it was difficult to carry out the destructive test of the prototype shaft lining. The model must be smaller than that of the prototype and meet the conditions of a similar simulation.It was necessary to find out the stress distribution on the cross-section of the model during the loading process and measure the failure load of the model. Therefore, the design of the shaft lining structure model should satisfy similar conditions of stress, deformation, and strength. According to the similarity theory and the basic equation of elasticity mechanics, the similarity index of the static shaft lining structure model was deduced by the equation analysis method .εCl/CδC = 1. According to the boundary equation, p/CσC = 1. According to the physical equation ECε/CσC = 1, vC = 1. εC is the strain similarity constant, lC is the geometric similarity constant, δC is the displacement similarity constant, pC is the load similarity constant, EC is the elastic modulus constant, and vC is the Poisson’s ratio constant.According to the geometric equation, l/CδC = 1 and εC = 1. Similar conditions of stress and deformation could be expressed as follows: p/CσC = 1, ECε/CσC = 1, and vC = 1.The HPSFRC shaft lining structure was a composite structure composed of several kinds of materials. The stress and deformation of the model had to maintain exact similarity to that of the prototype; thus, the geometry size of the model had to be similar to that of the prototype in the whole loading process. Therefore, we obtained RC), reinforcement ratio similarity constant (μC), and steel fiber content similarity constant (ρC). Only the geometric similarity constant could be chosen according to the need.In order to ensure that the failure load and form of the shaft lining structure model were completely similar to that of the prototype, both the stress-strain relationship under the elastic state and the strength of the model should satisfy similar conditions. Firstly, the stress–strain curve of the shaft lining model and the prototype material should be similar in the whole loading process. Secondly, the strength of all parts should be similar. Finally, the strength criterion should be similar. Obviously, to satisfy all of the above similarity conditions, the material of the model must be the same as the original shaft lining. Thus, all of the other similarity constants were equal to 1, including the strength similarity constant , as the specimen size was nonstandard . The numThe split tensile strength test results are shown in F–δ curve) was drawn, and the fracture toughness and fracture energy were calculated according to the following formulas [Y is a shape parameter. According to the load, deflection, and crack opening displacement measured, the load–deflection curve (formulas :(2)KIC=6F–CMOD curve was drawn. Then, tensile strength, instability fracture toughness, and fracture energy were calculated according to the following formulas [Considering the complexity of the mineshaft lining structure, to fully reveal the difference of tensile strength and fracture toughness between ordinary concrete and HPSFRC, a wedge splitting test was conducted. After that, the formulas ,21:(4)FHFrom the fracture morphology of the specimens in The data of tensile strength, toughness, and fracture energy of the wedge splitting test had no comparability to that of the direct tension and bending tests. However, they also verified that HPSFRC had stronger tensile, toughness, and crack resistance than ordinary concrete. Further, the ductility characteristics of HPSFRC were similar to those of the bending test.Strength tests were carried out on four model specimens. The ultimate bearing capacity of the model specimens is listed in The inner and outer edge strains of six sections were measured by strain gauges along the concrete surface. The strain variations in the middle section of the model specimen in the direction of large and small loads are shown in Due to poor ductility, the ordinary concrete model showed no obvious warning in the loading process, but in the end, it suddenly destructed. When destruction occurred, there was a loud noise, accompanied by massive concrete shedding. Local concrete was crushed, as shown in Under the action of a non-uniform load, the failure location of the shaft lining structure model was mainly located at the inner edge of the large load, where the concrete was subjected to eccentric pressure and bending moment, resulting in tensile stress, and local tensile cracks occurred during the loading process. Although the steel fibers hindered the rapid propagation of cracks, at the later stage of loading, the fracture location was still near that location. When the load was uniformly distributed, there was no bending moment and shear stress in all parts of the shaft lining, and the damage location was randomly distributed with the difference of construction quality.In the test, the model was always in the state of plane stress. When the model was in the stage of elastic deformation, the stress distribution of the inner and outer edges of the model conformed to the elastic theory. However, when the deformation transitioned from the elastic stage to elastoplastic or plastic stage, the constitutive relationship of concrete did not conform to Hooke’s law. For this reason, a single curve hypothesis was used for the steel bar. The deformation modulus and Poisson’s ratio were calculated by computer iteration and the stress values of the steel bar were obtained. Damage constitutive model was used for concrete according to “Code for Design of Concrete Structures”  and was The above mentioned mechanical properties and model tests of the shaft lining structure showed that HPSFRC can evidently improve the bearing capacity of the shaft lining structure under non-uniform loads because of its remarkable tensile strength, and crack resistance. Therefore, this new type of shaft lining structure was used for an 884–940 m section of the second auxiliary shaft underground bedrock section of the Pansan Coal Mine, which was under complex stress conditions.Short–excavation–short masonry technology with a 3.5 m cycle was adopted in the construction progress in the rock. When the shaft was excavated to an 884 m depth and entered the fault fracture zone, HPSFRC with steel bars was used to replace the original design of ordinary concrete with steel bars to construct the shaft lining structure of 800 mm thickness until the end of the 940 m depth.In order to dynamically and continuously evaluate the safety of the new type of shaft lining structure, the stress distribution and time variation of the structure must be studied and analyzed. Therefore, concrete strain gauges were embedded in four perpendicular horizontal directions along the circumference of the shaft lining at a 940 m depth. The strain–time curve of HPSFRC was obtained by real-time observation, as shown in (1)The mechanical property tests showed that the compressive, flexural, and tensile strengths of HPSFRC were 9%, 71%, and 53% higher than those of ordinary concrete, respectively. Adding steel fiber can evidently improve the tensile and flexural strengths of ordinary concrete but has little effect on compressive strength.(2)With the increase of the steel fiber content, the fracture toughness and fracture energy of HPSFRC increased. When the steel fiber content reached 1.5%, the fracture toughness reached 0.42 which was 75% higher than that of the ordinary concrete, and the fracture energy reached 2003.9 N/m which was 16 times that of the ordinary concrete. The improvement effect was remarkable. Steel fibers in HPSFRC have shown excellent crack resistance in various tests, and HPSFRC shows remarkable ductility characteristics.(3)The model test showed that adding a certain amount of steel fiber to the concrete of the shaft lining structure had a significant effect on improving the bearing capacity of the shaft lining, even if resisting non-uniform loads.(4)In the shaft lining model test under a non-uniform load, the stress and strain of the outer surface in the direction of a large load and the inner surface in the direction of a small load were evidently larger than those in other directions or surfaces. Further, the tensile characteristics appeared in the inner surface of the large load at the initial stage of loading, which posed a hidden danger to the failure of the shaft lining model in the later stage.(5)Due to the poor ductility of ordinary concrete, the fracture of the shaft lining model of ordinary concrete was sudden and without any warning. However, the steel fiber in the HPSFRC shaft lining improved the brittleness and ductility of the concrete. When the shaft lining lost its ultimate bearing capacity, the fracture surface was still connected by steel fibers. Therefore, under complex engineering geological conditions, HPSFRC can greatly delay deformation, even if the lining cracks. The characteristics of HPSFRC can greatly improve the safety of shaft lining structures.(6)It has been proved by practice that the strain of HPSFRC tends to be stable, and the strain value is far less than the failure value of its material. The structure operates safely due to HPSFRC remaining intact and reliable. It avoids damage to the shaft lining, as with other deep wells under complex conditions with faults or high crustal stress. Thus, this new type of support structure has definite application value in deep wells.