Experimental and numerical investigation on the failure mode and forced response characteristics of segmented lining structure under strike-slip fault movement

Abstract

Segmented lining structure is one of the effective measures to mitigate the risk of fault dislocation in tunnels crossing active fault zones. Based on background of the Xianglushan Tunnel crossing Longpan-Qiaohou Fault, the mechanical behavior of segmented lining structure for deep buried tunnel crossing complex active fault zone is studied by physical model tests. The results indicate that both the surrounding rock pressure and the lining strain decrease after the lining is segmented, and this characteristic becomes more pronounced as the segmented length decreases. The lining failure are also reduced to the range of upper influence zone. To further investigate the mechanism of segmented lining structure, a numerical model is established and damage characteristics of lining are estimated. The numerical results show that the tensile and compressive damage of lining are diagonally distributed under the conventional lining structure. Segmented lining structure enhances the rotational characteristics of the lining segments, weakens the action areas of the surrounding rock and the lining, and cuts the large-scale damage area of the lining in sections. As the segmented length decreases, these characteristics become more pronounced, and the structural adaptability of the lining becomes more evident. The friction angle, stiffness and width of segmented joint have a great impact on the lining failure, but the selection of segmented joint parameters should comprehensively consider the failure of the segmented joint and the segmented lining. The research findings provide suggestions for the prevention and control of fault dislocation in tunnels crossing active fault zones under similar conditions.