断层错动作用下隧道衬砌围岩破坏机理研究

依托西南地区某跨断层隧道工程背景,对断层错动下隧道围岩结构影响开展相似模拟试验和数值模拟研究。综合工况及试验条件,对一般三维模型装置和光纤监测布置等进行设计,试验装置可以更好地反映断层蠕滑错动作用下衬砌-围岩-断层带的动态关系及衬砌结构的损伤破坏特征。结果表明,隧道结构对围岩体有一定程度的“追随性”和“抑制性”,断层错动,整个模型结构内部应力重新分布,随着垂直错动量增加衬砌结构损伤破坏影响范围增大。错动影响下,衬砌结构各部分变化不一,左拱肩处破坏尤为严重,需注意拱肩处衬砌结构的塑性破坏。通过数值模拟试验对错动下跨断层隧道的影响进行进一步的研究,结果表明,围岩及衬砌结构的变形破坏趋势与相似试验相同。

Study on Coupled Failure Mechanism of Tunnel Structural Surrounding Rock under Fault Motion

Based on the background of a cross-fault tunnel project in southwest China, the effect of fault dislocation on surrounding rock structure of tunnel was studied by similar simulation test and numerical simulation. Based on the engineering conditions and test conditions, the general three-dimensional model device and the fiber-optic monitoring arrangement are designed. The test device can better reflect the fault creep and slip action, dynamic relationship between lining-wall rock-fault fracture zone and damage and failure characteristics of lining structure. The results show that the tunnel structure has a certain degree of "follow-up" and "restraint" to the surrounding rock mass, fault dislocation, and stress redistribution in the whole model structure, with the increase of the vertical displacement, the damage and failure range of the lining structure increases. The influence of dislocation on the lining structure varies in different parts, and the damage at the left Spandrel is especially serious, so the plastic damage of the lining structure at the Spandrel should be noticed. The influence of cross-fault tunnel under staggered motion is further studied by numerical simulation test. The results show that the deformation and failure trend of surrounding rock and lining structure is the same as that of similar test.