Study on Deformation Control of Large Deformation Tunnel in Soft Rock across Faults
Zhigang Tao, Weijun Lin, Yong Li, Kuiming Liu
Abstract
This study focuses on the area of large deformation of soft rocks across the fault in Dongmachang China to investigate support methods for fractured surrounding rocks Negative Poisson's Ratio (NPR) anchor cable support. The research employs field monitoring, 3D physical model experiments, and numerical simulations. The results show that: (1) the maximum settlement displacement of the Dongmachang Tunnel section with original support can reach about 476 mm and has an upward trend, the limit of initial branch intrusion is 41.2 cm, and the width of invert joint is 5–50 mm; (2) the dynamic impact experiment of NPR anchor cable shows that the NPR anchor can withstand several impacts, the maximum cumulative impact deformation within the range of constant resistance is 500–1,000 mm, and the impact resistance is strong; and (3) NPR anchor cable can effectively control the large deformation disaster of surrounding rock in the fault fracture zone of Dongmachang Tunnel, basically ensuring that the deformation of the surrounding rock is below 300 mm, and the control effect is good. These findings suggest that NPR anchor cables are effective for controlling large deformations in tunnels constructed through soft rock across faults and provide a scientific basis for implementing new support systems for other similar tunnels.