Experimental Study on Rock-Support Interaction in Deep Tunnel Under Complex Geological Conditions

Abstract

Rock-support interaction is one of the most core issues in underground engineering, which is of major interest to supporting structure design, construction safety and cost, as well as environmental protection. In order to study the rock-support interaction in deep tunnel under complex geological conditions, taking Xianglushan Tunnel of Yunnan Water Diversion Project in China as the engineering background, two true three-dimensional physical model tests were conducted. The model test results show: (1) the surrounding rock and support are a pair of opposite and united contradictions, which are both antagonistic and cooperative; (2) the rock-lining interaction and rock-bolt interaction are distinctly different. The lining is a type of outside supporting structure to bear the load from surrounding rock and the bolt is a kind of inside supporting structure to reinforce and protect surrounding rock; (3) the impacts of weak fault on mechanical behavior of surrounding rock and supporting structure are significant. The load bearing effects of surrounding rock and support system exhibit different characteristic depending on the corresponding geological conditions. The results can contribute to the development of construction scheme and optimization of support design, and also provide an ideal data set for the calibration and validation of numerical models to simulate the rock-support interaction.