基于广义Hoek-Brown准则的瞬时线性化强度折减技术  

Instantaneous linearization strength reduction technique for generalized Hoek-Brown criterion

作　　者：任晋岚 陈曦[1] 王冬勇 吕彦楠 REN Jin-lan;CHEN Xi;WANG Dong-yong;LÜYan-nan(Key Laboratory of Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学城市地下工程教育部重点实验室

出　　处：《岩土力学》2019年第12期4865-4872,共8页Rock and Soil Mechanics

基　　金：国家重点研发计划课题（No.2017YFC0804602）;中央高校基本科研业务费专项基金（No.2019JBM092）~~

摘　　要：广义Hoek-Brown(HB)准则广泛应用于岩体的计算和分析,然而,广义HB准则是典型的非线性强度准则,不能直接在有限元强度折减法中采用来开展岩体的稳定性分析。针对这一问题,开展瞬时线性化研究,根据已有的应力状态将HB强度包线上一点的抗剪强度转化为该点切线对应的黏聚力和内摩擦角,并提出了两种瞬时线性化强度折减方案:(1)基于弹塑性分析获得的应力场,对每个应力点专属的瞬时Mohr-Coulomb(MC)强度参数进行折减,相应的方法记为Point-IL-SSRFEM;(2)由于传统有限元法要求单元的抗剪强度参数保持不变,在每个单元上各个应力点获得瞬时MC强度参数后,对这些参数进行单元均一化处理并进行折减,相应的方法记为Element-IL-SSRFEM。基于岩质边坡算例,对比和评述了三参数等比折减技术和瞬时线性化强度折减技术。数值分析结果表明:与Element-IL-SSRFEM相比,Point-IL-SSRFEM对网格划分的要求较低,计算精度和计算效率相对较高;与三参数等比折减相比,Point-IL-SSRFEM的计算精度高、计算性能稳定。因此,推荐使用Point-IL-SSRFEM来分析岩质边坡的稳定性。The generalized Hoek-Brown(HB) criterion has been widely applied to the computation and analysis of rock mass. However, the generalized HB criterion is a typical nonlinear failure criterion, so that it can’t be directly used in conjunction with shear strength reduction finite element method(SSRFEM) for the stability analysis of rock slopes. In response to this problem, the instantaneous linearization technique is investigated, in which for an arbitrary stress point, the instantaneous cohesion and internal friction angle corresponding to a tangent line with respect to the HB envelope can be obtained. Consequently, two instantaneous linearization strength reduction schemes are proposed: 1) Based on the stress field attained from the elasto-plastic analysis, the Mohr-Coulomb(MC) strength parameters of each stress point can be reduced, and the resulting approach is denoted as Point-IL-SSRFEM;2) Since the strength parameters are required to be constant in each element for conventional finite element method, the attained instantaneous strength parameters for stress points in each element shall be averaged and then reduced, and the resulting approach is denoted as Element-IL-SSRFEM. Based on the calculation example of rock slope, the three-parameter strength reduction technique and the instantaneous linearization strength reduction technique are compared. The numerical results show that: compared to Element-IL-SSRFEM, the numerical accuracy and computational efficiency of Point-IL-SSRFEM are relatively high;Compared to the three-parameter strength reduction technique, the numerical accuracy of Point-IL-SSRFEM is higher and the computational performance of Point-IL-SSRFEM is more stable. Therefore, it is recommended to apply it to the stability analysis of rock slopes.

关 键 词：岩质边坡 广义Hoek-Brown准则 瞬时线性化 强度折减 安全系数 

分 类 号：TU457[建筑科学—岩土工程]