The Volume of Settlement Trough Change with Depth Caused by Tunneling in Sands

The Volume of the settlement trough is essential for estimating the settlement caused by tunneling. Generally, the volume of the settlement trough was recognized as a constant which was equal to the volume of the ground loss in the tunnel buried in clay. According to observation data from both laboratory and field tests, the volume of the settlement trough caused by tunneling in sands changed with depth, although the mechanism behind the volume change has not yet to be understood. In the present study, a largescale laboratory model test was conducted to investigate the volume change of the settlement trough with depth caused by tunneling in sands. The results show that the volume of the settlement trough decreased significantly with a decrease in depth. Based on the data from both literature and the current study, a modified model was proposed to estimate the settlement caused by tunneling in sands considering variation of the volume of settlement trough with depth.