穿越走滑断层的山岭隧道抗错断铰接设计试验研究

In the selection of routes for long mountain tunnels in the western region of our country, it is often necessary to cross active fault zones, facing the challenges of fault movement to structural design and safe operation. Taking the Xianglushan Tunnel in the Yunnan Central Water Diversion Project as the engineering background, based on a self-designed test device for simulating strike-slip fault movement, this paper studies the fracture characteristics of rock mass under strike-slip fault movement and the response laws and failure modes of a tunnel model with a hinged design. The test results show that: there is an obvious discontinuity in the surface displacement of the rock mass under strike-slip fault movement at the fault slip surface; the cross-section of the lining of the tunnel section intersecting with the fault slip surface changes from circular to vertical oval, and the deformation rate of the horizontal axis diameter reaches 6.57% under a given fault dislocation of 50 mm; the lining of the tunnel section intersecting with the fault slip surface has a horizontal deflection of about 5° under fault movement, and there is an obvious step between it and the adjacent tunnel section lining; compared with a continuous tunnel, the hinged design can significantly reduce the strain response of the lining structure. In addition, the failure modes of the hinged system tunnel are mainly circumferential cracks and oblique cracks, and both the degree and range of failure are significantly reduced.

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。