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隧道工程中常用的安全系数是一种评估隧道稳定性的有效指标。为了研究非线性破坏准则下浅埋隧道的稳定性,基于已有的直线型多块体破坏机制,采用切线法将非线性破坏准则引入上限定理的能耗计算,结合强度折减法,构建了极限状态下隧道安全系数的目标函数。采用序列二次优化迭代法对此目标函数进行优化,得到了浅埋隧道整体安全系数的上限解,并对不同参数作用下浅埋隧道安全系数的变化规律进行了研究。研究结果表明:非线性系数m对隧道安全系数和极限状态下隧道破坏面的影响十分显著。当其他参数一定时,安全系数随非线性系数m的增大而减小。极限状态下隧道破坏面随m的增大向外扩展,潜在破坏范围增大。
The safety factor commonly used in tunnel engineering is an effective indicator to evaluate the stability of the tunnel. In order to study the stability of shallow tunnel under nonlinear failure criterion, based on the existing linear multi-mass destruction mechanism, the tangent method is adopted to introduce the nonlinear failure criterion into the energy consumption calculation of the upper bound theorem. Combined with the strength reduction method, the limit The objective function of tunnel safety factor under state. The objective function is optimized by the sequential quadratic optimization iteration method. The upper bound solution of the overall safety coefficient of shallow tunnel is obtained. The variation rules of the safety factor of shallow tunnel under different parameters are studied. The results show that the influence of the nonlinear coefficient m on the tunnel safety coefficient and the failure surface of the tunnel under extreme conditions is significant. When the other parameters are constant, the safety factor decreases with the increase of nonlinear coefficient m. In the limit state, the failure surface of tunnel expands outward with the increase of m, and the potential damage range increases.