Stability Study of Surrounding Rock with Model Test and Numerical Simulation for Highway Tunnel in Multi-cavern Area

 

Rao Jun-ying*, Liu Yun-si, Yin Quan

School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
*Corresponding author: rao-ale@163.com

Rao Jun-ying*, Liu Yun-si, Yin Quan

School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
*Corresponding author: rao-ale@163.com

Rao Jun-ying*, Liu Yun-si, Yin Quan

School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
*Corresponding author: rao-ale@163.com

 

 ABSTRACT

A comprehensive research study has been carried out of the stability of surrounding rock for excavating tunnel in multi-cavern area of Baishan Tunnel. The study included both a physical and a computational model. In the physical tests the geometric similarity ratio was 1/40 and multi-cavern models made up of 4 different combinations of karst caves were tested. Barite powder, plaster powder, and cement were mixed together in a particular proportion to simulate the valley (referred to as V) of surrounding rock. The 3D numerical simulation was performed using commercially available software. The results show: ? the mixture is a proper similar material for V surrounding rock; ? it leads to about 80% of final displacement at vault when caves are above vault, while its only about 60% without caves; ? the final displacement conforms to the law of Vault > Left haunch > Right haunch, and the final displacement of left haunch is 1.2~2.2 times larger than that of right haunch. Moreover, the Displacement-Time curves of the surrounding rock during tunnel excavating showed an S shape which were fitted with the logistic curve, and obtained a reasonable correlation coefficient.

Keywords: tunnel engineering; stability of surrounding rock; model test; numerical simulation; multi-cavern

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