【摘要】 对邓肯–张模型的特点进行了分析,指出待反演的参数中若同时包含破坏比Rf、凝聚力c和内摩擦角?容易导致反演失败的原因在于反演结果不唯一所引起的数值奇异。证明了不唯一性源于参数Rf,c,?之间的一种特殊相关性,即,对于任一特定的应力状态,有无数种Rf,c,?组合可以保证Rf S(破坏比Rf与应力水平S的乘积)取值不变并获得相同的切线模量Et和切线泊松比νt,导致满足反演目标函数获得相同最小值的参数组合出现不唯一性。提供了相应的解决方法,即重新拟定反演参数或约束Rf,c,?中的某些参数,以确保模型参数的可辨识性。更多还原

【Abstract】 The fact that the back analysis procedure simultaneously selecting failure ratio,cohesion,and frictional angle as objective parameters in Duncan-Chang hyperbolic constitutive model tends to fail is caused by numerical singularity because of non-uniqueness of the solution.The non-uniqueness arises from the co-relation of,,and,which means there are innumerable groups of,,and which can form the same(product of failure ratio and stress level) and produce the same tangent modulus and tangent Poisson ratio under specific stress condition and finally provide the same objective value in back analysis.Effective methods are given to ensure the identification of Duncan-Chang hyperbolic constitutive model during back analysis by means of parameter reconstruction and parameter constraint.更多还原