STUDY ON LAW AND CONTROL MEASURES OF GROUND DEFORMATION DURING EPB SHIELD TUNNELING PROCESS IN SMALL-SPACING DOUBLE-TRACK TUNNELS

It is inevitably that the process of EPB shield tunneling disturbs the rock and soil around tunnel, which has intensively caused ground deformation and threatened the safety of surrounding structures/buildings. To study the law and control measures of ground deformation during the EPB shield tunneling process, this paper, based on the Longzhen Exit and Entry lines of Guangzhou Rail Transit Line 18,analyzed the shield construction parameters and ground deformation data caused by the construction of this small-spacing double-track tunnels. The conclusions are as follows:the ground deformation experiences five development stages with four deformation trends during the EPB shield tunneling process in small-spacing double-track tunnels; the ground deformation effect of the pre-built line on the later-built line is generally consistent with the effect of the pre-built line on itself, while the significant influenced area is between the two tunnel axes; the influence factors of ground deformation include shield construction parameters, engineering geological conditions and shield downtime, so optimizing the shield construction parameters, reinforcing the stratums and reducing shield downtime can effectively control the ground deformation. The research results have provided theoretical basis in area of shield construction control of Guangzhou Rail Transit Line 18 and other relevant small-spacing double-track tunneling projects.