赵勐 肖明 陈俊涛 金汉城

摘   要：為研究层状岩体对隧洞地震响应的影响，考虑地震动斜入射特性和层状岩体层间非线性接触特性，建立一种层状岩体水工隧洞地震动力响应数值模拟方法. 首先，基于三维黏弹性人工边界条件和波场分解理论，将地震动转化为作用于人工边界上的等效节点力，建立了一种层状岩体中地震动三维空间斜入射输入方法. 其次，针对地震作用下层状岩体层间动力相互作用特点，建立了一种考虑接触面黏结滑移特性的动接触力算法. 将该模拟方法应用于巴基斯坦阿扎德帕坦水电站输水隧洞抗震稳定计算，对比分析地震动竖直入射、地震动斜入射、地震动斜入射且考虑动接触3种工况的计算结果，结果表明，地震作用下隧洞结构的应力和位移响应受地震动入射角影响明显;层间剪切、挤压破碎带的存在加剧了隧洞的地震反应，接触面附近破坏区发展较大;考虑接触作用后，衬砌腰部的应力和位移响应相比顶拱较大，首先发生开裂损伤破坏，成为水工隧洞衬砌结构抗震设计的薄弱部位，隧洞结构的损伤区主要分布于软岩穿过部位和层间接触部位.

关键词：层状岩体;水工隧洞;地震动斜入射;动接触力法;地震响应;数值模拟

中图分类号：TU45                              文献标志码：A

Abstract：In order to study the influence of layered rock mass on tunnel seismic response， considering the oblique incident angles of seismic motion and the nonlinear contact characteristics at the interface， a numerical simulation method for seismic response of hydraulic tunnel in layered rock mass was proposed. First， based on the 3D viscoelastic artificial boundary conditions and the wave field decomposition theory， the input method of an obliquely incident earthquake in layered rock mass was put forward. It can transform the seismic waves into equivalent nodal forces acting on the nodes of artificial boundaries. In view of dynamic interaction characteristics between interlayers in layered rock mass under seismic action， a dynamic contact force algorithm considering the bond-slip characteristics of the interface was presented. Then， the methods were applied to the anti-seismic stability calculation of the hydraulic tunnel of AZAD PATTAN hydropower station in Pakistan. The calculation is divided into three different working conditions， with vertically incident earthquake， with obliquely incident earthquake but no dynamic contact force， with obliquely incident earthquake and dynamic contact force. The results indicate that the stress and displacement of the tunnel structure under seismic action are greatly affected by the angle of incidence. The existence of interlayer shearing and crushing fracture zone exacerbates the seismic response of the tunnel， resulting in the fact that the failure zone near the interface develops further. After considering the contact effect， the stress and displacement response of the haunch is larger than that of the vault， so that the haunch of lining where the cracking damage first occurs is the weak part of lining structure under the action of earthquakes. The damage zone of the lining mainly distributes in the place where the soft rock passes through and interlayer contacts.

Key words：layered rock mass;hydraulic tunnel;obliquely incidence earthquake;dynamic contact force method;seismic response;numerical simulation

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