ABSTRACT
A method to be able to simulate induced ground settlement by Rectangular Tunnel Boring Machines (RTBMs) will allow engineers to predict possible ground deformations and put in place measures to mitigate the risk of settlements. In this paper, displacement controlled numerical methods (DCM) based on the gap methods proposed by this study and Ng (2017) are used to predict the ground settlement caused by RTBM. The former assumes that the deformed tunnel shape is similar to the original excavated shape, while the latter assumes that the four corners of the rectangle segment is considered to be fixed. The trend and the magnitude of the settlement will be used as a basis of comparison to see whether the two DCMs are suitable to back analyse the transverse settlement. The DCM by Ng (2017) is more applicable to back analysing the RTBM drive from before it approaches towards the end of the drive whereas the proposed DCM in this study is more applicable to back analysing measurements that have been taken at a short time frame after the drive has been completed.
