Analysis of Excavation-induced Deformation with Different Soil Models
Abstract: The monitored case of deep excavation works located in the centre of Warsaw is described and back analysed as a boundary value problem with the finite element method. The excavation was carried out in over-consolidated clayey layers under the support of braced diaphragm walls. Accurate simulation of such soil-structure interaction problems requires advanced soil constitutive models – especially for the pre-failure range of small strains. On the other hand, such models should not be very complex and their material parameters should be relatively simple to obtain from laboratory and in situ surveys. By means of a case study, this paper examines several simple elasto-plastic constitutive models for the simulation of the behaviour of soil layers. The influence of such characteristics of the soil behaviour, as anisotropy and non-linearity of stiffness, is studied in the paper. The discussion concerns the problems related to the application of the models for a practical example. The comparison is focused on the obtained and measured displacements of the neighbouring building and diaphragm walls.
Geotechnical Analysis of Structural Behaviour Under Complex Geological Engineering Conditions
Abstract The article deals with the effect the geological engineering conditions have on the behaviour of structures under conditions of North-Western soft soils. A structural survey conducted at an oil refinery in the Leningrad region showed numerous faults and damages caused by settlements of the bearing structures and their foundations. Traces of leakages on the retaining walls of the pumphouse as well as next to the pipeline inlets witness a man-triggered raise of the ground water level. Crack formation in bottoms and walls of the aerotanks and sludge tanks was also denoted. It might be caused by the reduction of foundation soil bearing capacity. In its turn, deterioration of physical and mechanical features of the foundation soil is linked to the change in the hydrological regime of the area, which is proved by rich seepage of ground waters through the cracks in tanks. Having analyzed the structural and geological engineering conditions the authors recommend elaborating and performing a project to restore the proper working order of structures.
Seismic and Sequence Analysis of Middle to Late Miocene Deposits of Northeast Java Basin
DOI: 10.17014/ijog.2.2.101- 110 This study is focused on Middle to Late Miocene sediments. As depicted in the regional geology of Indonesia, the area of study is part of Northeast Java Basin. There are three phases of tectonism in the basin: extensional tectonics at Eocene-Oligocene time, compressional tectonics at Middle Miocene, and compressional tectonics at Miocene-Pliocene time. The result of the study shows three sequences were developing during Middle to Late Miocene, those are: (1) Middle Miocene sequence-1 (MM-1 sequence) consisting of a Lowstand Tract System deposition in Middle Miocene-1 (LST MM-1), Transgressive System Tract deposition in Middle Miocene-1 (TST MM-1), and Highstand System Tract deposition in Middle Miocene-1 (HST MT-2); (2) Middle Miocene sequence-2 (MT-2 sequence), comprising Transgressive System Tract Middle Miocene-1 (TST MM-2), and Highstand System Tract deposition in Middle Miocene-1 (HST MM-2); (3) Late Miocene sequence-1 (LM-1 sequence), composed of a Lowstand Tract System deposition in Late Miocene -1 (LST LM-1) and a Transgressive System Tract deposition in Late Miocene-1 (TST LM-1).