基于广义Hoek-Brown非线性破坏准则的节理岩体地基承载力研究

STUDY OF BEARING CAPACITY OF JOINED ROCK MASS FOUNDATION BASED ON GENERALIZED HOEK-BROWN NONLINEAR FAILURE CRITERION

针对节理岩体非线性破坏特征,发展基于Hoek-Brown破坏准则的临界滑动场理论进行节理岩体地基承载力的计算。首先将Hoek-Brown准则的剪切强度逐点等效到Mohr-Coulomb强度线上,求得每点的瞬时内摩擦角和瞬时黏聚力;在此基础上,改进基于Mohr-Coulomb准则的临界滑动场理论,建立新的迭代算法,将Hoek-Brown强度准则与临界滑动场理论结合起来,求解被动土压力和地基承载力。同时,综合分析GSI和mi值对地基承载力的影响。算例对比分析结果表明,该方法能迅速准确地确定节理岩体地基最危险破坏滑面并得到相应的地基极限承载力值。

Considering the nonlinear failure characteristics of jointed rock mass, the critical slip field method is modified based on the generalized Hoek-Brown failure criterion to calculate the bearing capacity of joined rock mass foundation. By transforming the shear strength of each point on the Hock-Brown strength envelope into the Mohr-Coulomb linear relation, transient internal friction angle and cohesion of each point are calculated; and the critical slip field method based on the Mohr-Coulomb criterion is improved and a new iterative procedure is thus established. Using the newly developed critical slip field method based on the Hock-Brown failure criterion, the passive earth pressure and ultimate bearing capacity of jointed rock mass foundation are computed. The effects of values of GSI and mi on ultimate bearing capacity of foundation are comprehensively analyzed. The results of comparative studies show that the proposed method can accurately determine the critical slip surfaces and associated values of ultimate bearing capacity of jointed rock mass foundation with reasonable accuracy.