中文摘要：

基于有限差分分析（FLAC）的软质岩石地基承载力数值计算模型,分析中将软质岩石地基视为均质、各向同性的连续介质,采用理想线性弹塑性本构关系模拟和Hoek-Brown非线性破坏准则及非关联流动法则。为便于数值模拟,采用切线法,把Hoek-Brown非线性破坏准则转换成Mohr-Coulomb线性破坏准则,并依据等量原则推导了瞬时内摩擦角和瞬时黏聚力的计算公式,编制了基于FLAC内置FISH语言的子程序。通过施加竖向速度向量,分别获得了圆形基础下考虑和忽略岩体自重的极限承载力。与理论值和现场载荷板承载力试验结果进行的对比分析表明,Hoek-Brown解结果比Bell解结果更接近实测值,但都偏于保守,而数值计算结果与实测值非常接近,特别是在考虑自重的情况下,误差仅为2%。说明对于软质岩石地基的极限承载力,采用基于Hoek-Brown非线性破坏准则的FLAC数值模型进行分析是合适的。

英文摘要：

A numerical calculation model of the ultimate bearing capacity of soft rock foundation based on the fast lagrangian analysis of continua （FLAC） is presented.The soft rock foundation is assumed as homogeneous,isotropic and continuous material which exhibits perfect linear elatoplasticity.According to the failure feature of rock,the Hoek-Brown nonlinear failure criterion and non-associated flow rule that can consider dilation angle of soft rock is used in analysis.To simulate easily,the Hoek-Brown nonlinear failure criterion is transformed to Mohr-Coulomb linear failure criterion by tangent method.The formula of instantaneous internal friction angle and instantaneous cohesion are derived from principle of equivalency;and then subprogram is compiled based on FISH language in FLAC.So the ultimate bearing capacity of circular footing on weight or weightless rock foundation is gained through adding vertical velocity vector.By comparing to theoretical values and in-situ values,the result is obtained of which the value from Hoek-Brown solution is more close to in-situ value than that from Bell solution;but all of them are too conservative.However,the numerical results are in better agreement with the in situ results.Especially there is only two percent deviation in the condition of considering gravity.It is shown that the numerical simulation by FLAC based on Hoek-Brown nonlinear failure criterion is appropriate to calculate ultimate bearing capacity of soft rock foundation.