Experimental study of the overconsolidation and saturation effects on the mechanical characteristics and residual strength of Chlef river sandy soil
This paper presents a laboratory study of the influence of the saturation evaluated in terms of Skempton´s pore pressure coefficient (B) and overconsolidation ratio (OCR) on the behavior of Chlef sand. The study is based on drained and undrained triaxial compression tests which were carried out for Skempton´s pore pressure coefficient varying between 13 and 90% and OCR varying between 1 and 8. Tests were conducted on medium dense sand samples having an initial relative density Index Id = 0.5 at an effective stress of 100 kPa. The paper is composed of two parts. The first one presents the characteristics of the sand used in this study, the second provides an analysis of the experimental results and discusses the influence of Skempton´s pore pressure coefficient (B) and OCR on the mechanical characteristics of the sand. The tests show that the increase in the Skempton´s pore pressure coefficient (B) reduces the soil dilatancy and amplifies the phase of contractancy and reduces the frictional and characteristic
angle of the sand. The increase of OCR improves the stiffness of sand and accelerates the appearance of dilatancy; and increases frictional and characteristic angle of the sand. Moreover, the present study focuses on the effect of saturation and overconsolidation on the residual shear strength of sand.
Experimental Investigation on Undrained Shear Behavior of Overconsolidated Sand-Silt Mixtures: Effect of Sample Reconstitution
Liquefaction stability analysis using the undrained shear strength characteristics of sandy soils that are prone to liquefaction is a major challenge in geotechnical earthquake engineering. The objective of this laboratory research work was to study the combined effect of the sample reconstitution (dry funnel pluviation and wet deposition) and overconsolidation ratio (OCR = 1, 2, 4, and 8) on the undrained shear strength of medium dense (D_r = 52 %) sand-silt mixtures under undrained monotonic loading conditions. For this purpose, a series of triaxial tests were carried out on reconstituted saturated silty sand samples with fines content ranging from 0 to 40 %. The confining pressure was kept constant to 100 kPa in all tests. The obtained data showed that the dry funnel pluviated samples were more resistant than the wet deposited samples and complete static liquefaction of samples reconstituted with wet deposition method was observed for the lower overconsolidation ratios (OCR = 1, 2, and 4). The undrained shear strength decreases with the increase of fines content for dry funnel pluviation (DFP) and the inverse tendency was observed in the case of wet deposition (WD) for the range of the overconsolidation ratio under consideration (1 ≤ OCR ≤ 8).
Using Infrared Thermography to Detect Moisture in Historic Masonry: A Case Study in Indiana
Nondestructive testing mapped water infiltration in the decoratively painted interior of a Masonic Temple in Muncie, Indiana.