为了采用非线性准则(巴顿准则)定量描述隧道岩体的稳定性,首先通过理论分析,推导巴顿非线性准则和摩尔库仑线性准则之间的关系,得到采用巴顿准则参数节理粗糙系数JRC和岩体压缩强度JCS表征的岩体剪切强度参数黏结力c、内摩擦角φ和巴顿准则参数表征的单元安全系数Ke;然后,利用有限差分软件FLAC3D建立隧道开挖计算模型,基于其内置的FISH语言,编制巴顿准则下非线性单元安全系数Ke计算程序,并对比Ke≤1的区域和FLAC3D塑性区分布。研究结果表明:Ke≤1对应的区域和由FLAC3D计算得到的塑性区域大致相同,从而验证了所推导的基于巴顿准则参数的单元安全系数公式的正确性以及所编制程序的可行性;单元安全系数Ke能够表征各个单元的破坏程度,优于塑性区判定标准。
In order to describe the stability of tunnel rock mass by the nonlinear failure criterion (Barton criterion),firstly,the relationship between Barton nonlinear failure criterion and the Mohr-Coulomb linear failure criterion was deduced,and the shear strength parameters of rock mass,i.e. cohesion c and friction angle φ,were obtained by the Barton criterion parameters,i.e. joint roughness coefficient JRC and rock mass compressive strength JCS,then the element safety factor Ke was obtained based on the parameters from the Barton nonlinear failure criterion. The tunnel excavation model was built by the finite difference software FLAC3D,and the calculation program for the nonlinear element safety factor Ke was compiled with the internal FISH program. The area of Ke≤1 was compared with that of plastic zone distribution calculated by FLAC3D. The results show that they are almost the same. The deduced equation for the element safety factor based on the Barton criterion parameters and the program built are correct,and the nonlinear element safety factor Ke can reflect the yield degree of each element,which is superior to the plastic zone distribution standard.