穿越走滑断层的山岭隧道抗错断铰接设计试验研究

我国西部地区的长大山岭隧道在选线时多要穿越活动断裂带，面临断层运动对结构设计和安全运行的挑战。该文以滇中引水工程香炉山隧洞为工程背景，基于自主设计的用于模拟走滑断层运动的试验装置，研究走滑断层运动下岩体的破裂特性以及采用铰接设计的隧道模型的响应规律和破坏模式。试验结果表明：走滑断层运动下岩体地表位移在断层滑动面处存在明显的不连续；隧道与断层滑动面相交的节段衬砌横截面由圆形变为竖椭圆，且在给定50mm的断层错动量下水平轴直径变形率达到6.57%；隧道与断层滑动面相交节段衬砌在断层运动下产生约5°的水平偏转，且与相邻节段衬砌间有明显错台发生；与连续隧道相比，铰接设计可以显著降低衬砌结构的应变响应。此外，铰接体系隧道的破坏模式以环向裂缝和斜裂缝为主，在破坏程度和范围上均明显减小。

Experimental study on articulated design of mountain tunnel crossing strike-slip fault zones

Mountain tunnels in western China usually intersect with the active fault zones during the processes of route selection, and the challenges of fault movement posed to structural design and safe operation have to be faced. The Xianglu mountain tunnel, which is the first portion of the Dianzhong water diversion project, is taken as an example in this study. Based on the new experiment equipment for simulating strike-slip faulting, the rupture characteristics of rock masses and the response characteristics and failure modes of the tunnel model with articulated design are investigated. The results show that the displacement of ground surface under strike-slip fault movement has obvious discontinuity at the fault slip surface. The cross-section of the tunnel intersecting with the fault slip surface changes from the circular shape to the vertical ellipse, and the rate of diameter deformation of the horizontal axis reaches 6.57% under a given fault displacement of 50 mm. The segment lining has a horizontal deflection of about 5° under strike-slip faulting, and meanwhile there is an obvious misalignment between the adjacent segment linings. Compared with the continuous tunnel, the articulated design can significantly reduce the strain response of the lining structure. Furthermore, circumferential and oblique cracks dominate the failure modes of tunnel in articulated design, which are significantly smaller than those of continuous tunnel in terms of damage extent and range.