基于FLAC~(3D)的强度折减法和点安全系数法对比

编制了强度折减fish命令流,推导了基于快速拉格朗日有限差分法的三种点安全系数计算公式,采用安全系数为1.0的ACADS边坡考题比较了强度折减法和点安全系数法在边坡失稳破坏判识及安全系数计算中的精度和可靠性,计算表明:Flac3D的solve fos强度折减模块计算的安全系数为0.99,编制的强度折减法fish命令流得到的安全系数精确到0.994,对应边坡表层控制监测点合位移增量与强度折减系数增量之比的急剧变化点、边坡剪应变增量贯通区、塑性区连通状态及迭代求解的不收敛性。强度储备法、最小距离法和线弹性公式计算的点安全系数分布规律一致,不仅能较好地揭示出边坡的失稳状态及滑面位置,同时可以反映边坡不同位置的安全系数。强度储备法公式和线弹性公式计算的连通性滑面安全系数为1.002,最小距离法公式计算的连通性滑面安全系数为1.0018。最小距离法公式更接近边坡考题的安全系数裁判值1.0。

Contrast on Strength Reduction Method and Point Safety Factor Method with FLAC3D

The fish command stream of strength reduction method is coded,and three point safety factor methods based on fast Lagrangian finite difference theory are deduced.With the ACADS slope illustrative example whose safety factor is 1.0,the accuracy and reliability of the strength reduction method and point safety factor method are contrasted in determining the limit equilibrium status and safety factor of the slope.The results show that the strength reduction method corresponds to the rapid change of the ratio of resultant displacement increment to the strength reduction factor,generalized plastic strain connection zone,plastic zone connection and the non-convergence of iterative solution,the point safety factor from solve fos program in Flac3D is 0.99,while the one from the coded Fish command stream is correct to 0.994.The point safety factor distributions from the strength reserve formula,minimum distance formula and linear elasticity formula are similar,which could not only better reveal the limit equilibrium status and failure surface of slope,but also reflect the different point safety factors in any position of slope.The point safety factor on failture connection zone from strength reserve formula and linear elasticity formula are both 1.002,while the result from the minimum distance formula is 1.0018,which is closer to the judgment result 1.0 from the slope illustrative example.