非线性西原体模型及其应用

Nonlinear nishihara model and its application

为全面描述岩石蠕变各个阶段,通过将西原体模型中黏性系数修正成与时间有关的函数,并增加一个考虑岩石弹性模量时效损伤的弹性体,以此来表征岩石蠕变硬化和蠕变损伤,从而建立一个新的岩石非线性蠕变模型。根据塑性力学理论给出该模型的三维蠕变方程,采用Levenberg-Marquardt算法对相关蠕变实验数据进行非线性拟合,反演得到岩石蠕变参数,同时对参数λ2进行敏感性分析。结果表明:拟合曲线与实验数据吻合较好,说明该模型可以较好地反映岩石蠕变各个阶段曲线特性,参数λ2取值越大,岩石进入加速蠕变的时间越短,岩石破坏越剧烈。

In order to fully describe the each stage of rock creep,through modified the viscosity coefficient in the Nishihara model into a time-dependent function and add an elastomer considering time-dependent damage of the elastic modulus of the rock,the creep hardening and creep damage of the rock were characterized,a new nonlinear creep model of rock is established.According to the theory of plastic mechanics,the three-dimensional creep equation of the model is given,Levenberg Marquardt algorithm is used to nonlinear fit the relevant creep experimental data and the creep parameters of rock are obtained by inversion,at the same time,the sensitivity of the parametersλ2 is analyzed.The results show that the fitting curve is consistent with the experimental data,which shows that the model can better reflect the curve characteristics of each stage of rock creep.The larger the value of the parameterλ2,the shorter the time for the rock to enter accelerated creep and the more severe the rock damage.