OasisLMS

Deep Excavations are required for the construction of various infrastructure projects such as underground metro stations, cut and cover box for transportation & utility tunnels, deep shafts for TBM launching & retrieval, cofferdams and building projects like basement construction. To facilitate deep excavations appropriate earth retaining systems are required. An earth retaining system consists of embedded retaining wall along with lateral supporting systems. Some of the embedded earth retaining wall commonly used in urban infrastructure projects are Diaphragm Wall, Secant Bored Pile Wall, Contiguous Bored Pile Walls. The lateral supporting systems such as struts & walers and ground anchors and permanent slabs are used along with embedded retaining walls to stabilize the deep excavations. In this paper a case study of a metro station supported by Diaphragm Wall along with permanent slabs and temporary struts is considered. Top-down construction methodology is adopted. The soil strata consist of thick deposits of soft clay layers followed by medium dense to dense sand. This paper focus on the study of behaviour of Diaphragm wall by varying ground conditions and ground model conditions along with lateral supports. The various effects considered are i. Effect of tension cracks, ii. Effect of undrained and drained soil conditions, iii. Effect of variation of ground water conditions and iv. Effect of variation of constitutive soil models i.e., Mohr Coulomb and advanced soil models such as Cam Clay Model (clay) & Hardening Soil Model (sands). The Finite Element based software namely PLAXIS 2D is used for the analysis. The analysis results are summarized, and the findings are concluded in this paper.

Sowmiyaa V S, L&T Construction, Heavy Civil Infrastructure IC; Suresh Chikati, L&T Construction, Heavy Civil Infrastructure IC

International Conference Proceedings