摘要
陡倾角断层带是地下洞室抗震稳定性的薄弱环节。针对围岩和断层的复杂动力相互作用特点,在Ladanyi剪切强度模型的基础上引入震动劣化系数,建立了考虑非线性力学特性和震动劣化效应的抗剪强度模型。进一步考虑围岩和断层的非连续变形特性,提出了一种考虑复杂抗剪强度和多种接触状态的三维动接触力算法。将该算法应用于金川地下厂房,研究其受陡倾角断层F31影响下的地震破坏特性。结果表明:考虑接触面和震动劣化效应后,洞室的地震反应增大,围岩和断层的错动更加明显,且发生一定深度的脱开、滑移破坏;陡倾角断层在主厂房高边墙切割出围岩厚度较薄的薄弱区,产生较大的变形和损伤,在上下游边墙分别易发生向洞内的弯曲倾倒变形和滑移变形;围岩和断层接触面的滑移脱开区分布随地震过程动态变化且不断向深部延伸,其中拱座和岩锚梁部位的脱开区范围较大。数值结果揭示了陡倾角断层下地下洞室围岩的动力破坏机制,可为抗震设计提供参考。
The steeply dipped fault zone is the weak link of the seismic stability of underground caverns. Aimed at the complex dynamic interaction characteristics between surrounding rock and faults, based on the Ladanyi’ shear strength model, a seismic deterioration coefficient was introduced, and a shear strength model considering nonlinear mechanical properties and seismic deterioration effect was established. Given the discontinuous deformation characteristics between surrounding rock and faults, a three-dimensional dynamic contact force method was proposed, which considered both the complex shear strength and multiple contact states. The method was applied to Jinchuan underground powerhouse to study its seismic damage characteristics under the influence of the steeply dipped fault F31. The results indicate that after considering the interfaces and seismic deterioration effect, the seismic response of the cavern increases, the dislocation between the surrounding rock and faults is more evident, and a certain depth of separation and sliding failure zones occurs. The steeply dipped fault cuts the high sidewalls of the main powerhouse, and forms a weak zone where the surrounding rock thinness is thin, resulting in larger deformation and damage. The flexural toppling deformation and slipping deformation into the cavern tend to occur on the upstream and downstream sidewalls, respectively. The distribution of the sliding and separation failure zone of the interfaces between surrounding rock and faults changes dynamically with the seismic process and extends to the depth. Among them, the separation zone is relatively large at the arch abutment and rock anchoring beam. The numerical results reveal the dynamic failure mechanism of surrounding rock of underground cavern intersected by a steeply dipped fault, which can provide reference for seismic design.
作者
陈世杰
肖明
王小威
陈俊涛
CHEN Shi-jie;XIAO Ming;WANG Xiao-wei;CHEN Jun-tao(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan,Hubci 430072,China;Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering,Ministry of Education,Wuhan University,Wuhan,Hubei 430072,China;Changjiang Institute of Survey,Planning,Design and Research,Wuhan,Hubei 430010,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第9期2600-2610,共11页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.52079097,No.51579191)
国家重点研发计划(No.2015CB057904)。
关键词
地下洞室
陡倾角断层
动接触力法
地震响应
破坏特性
underground cavern
steeply dipped fault
dynamic contact method
seismic response
damage characteristics
