Finite Element Analyses Of Jakarta MRT Deep Excavation Project

This study is to aimed and establish the key of geotechnical properties and numerical models for modeling deep excavation in Jakarta,Because of limited knowledge of subsurface soil conditions and experience on deep excavation analysis in Jakarta.The first part of research work was to determine the geological conditions and compile subsurface soil information in Jakarta from previous literature and report.In Jakarta the soft soil from 0-15 m below the ground surface with SPT N < 4 is commonly found.The geotechnical problems and nature hazard in Jakarta such as Land subsidence,flood and earthquake were also discussed.The second part of research work was to carry out 2D and 3D finite element analysis for modeling deep excavation of Bundaran HI Mrt Station in central Jakarta.A series of parametric studies was conducted to evaluate the influence of soil constitutive model.(MohrCoulomb and Hardening Soil Models),Drainage condition(total or effective stress analysis)and input parameters(soil and diaphragm wall stiffness and soil-structure interface property).On the result for diaphragm wall deformation and ground settlement in 2D FE analysis,the result showed that the maximum wall deformation at final excavation stage was around 0.27%(right wall)and 0.2 %(left wall)of excavation depth and located at the top of the wall.The ground settlement was spandrel type and the ratio of horizontal movement and vertical movement was larger than 1.0.In 3D FE analysis,the numerical result showed that the corner effect existed within a distance of 30 m from the corner excavation.the ground surface settlement at the corner excavation was around 20%-40% of the ground settlement.The stress path in 2D and 3D analysis were were investigated and the result showed the stress states of soil element highly depended on their location.Last,Based on the numerical results,the evaluation of adjacent building damage and suggestions for building protection measures were discussed.