2D GROUND MOVEMENT SIMULATION DUE TO TUNNEL EXCAVATION USING FINITE ELEMENT METHOD

2D ground movement study is an essential effort in optimizing the preliminary
design and planning of tunneling project. Empirical, analytical and numerical methods
have been widely used to estimate the changes of the soil settlements during tunnel
excavation. However, empirical and analytical methods are insufficient as they cannot
fully visualize the actual settlements happened. Thus, this leads to the vast growth of
numerical modelling. This report describes the project on Finite Element Method (FEM)
application using staged construction via PLAXIS 2D to predict the 2D ground
movements due to the induced tunnel excavation. Transverse settlement and volume loss
of soil are the outputs of the studies. The simulation is validated by comparing the result
produced with Gaussian curve and actual field data from part of the MRT line 1. Next,
the parameters studied are type of soil model, initial stress condition and calculation methods such as β-method and contraction method. The effects of these parameters
towards ground settlement and ground loss ratio are investigated and discussed. The
results show that the most suitable numerical approach in Plaxis 2D is using Hardening Soil model with β-method. Using β-method is also vital in studying the effect of the
delayed tunnel lining construction in transverse settlement. The greater the delayed
tunnel lining construction time, the greater ground settlement is expected.