含软弱夹层围岩计算模型分析及危险度评估

Calculation Model Analysis and Risk Assessment of Surrounding Rock with Weak Interlayer

基于含软弱夹层围岩的力学计算和屈服破坏分析,根据软弱夹层的受力变形的特点,通过简化提出了计算夹层边界应力的组合梁结构模型,并推导出相应的方程组.以马家河隧道为例,求解对应方程组,并将理论计算结果与数值软件计算结果进行对比和误差分析,验证了模型的可行性.同时利用Mohr-Coulomb准则提出了评估围岩危险程度的ξ系数及其相应的计算公式,并将其应用于马家河隧道中含软弱夹层的围岩地段进行分析,根据ξ系数对围岩进行了危险等级分区,并结合位移分布进行对比分析.

According to the deformation characteristics of weak interlayer,a simplified composite beam structure model was proposed and a set of functions was deduced to calculate the stress of interlayer boundary,based on the analysis of surrounding rock with weak interlayer on mechanical calculation and yield failure.Taking Majiahe tunnel for example,the results of theoretical calculation and numerical software calculation results were compared and the error was analyzed after solving the corresponding equations.And the feasibility of the proposed model was verified.Meanwhile,the risk coefficientξand corresponding calculation formula were put forward to evaluate the dangerous level of surrounding rock with weak interlayer with Mohr-Coulomb criterion using in Majiahe tunnel.According to the coefficientξ,the risk grade of the surrounding rock was devided.The results were analyzed combined with the displacement distribution.