采用强度折减法确定含软弱夹层岩质边坡安全系数

 应用FLAC3D数值模拟软件，采用强度折减法，求解常德—张家界高速公路某段含软弱夹层的岩质边坡安全系数，讨论了求解效率及失稳判据等。实际运用表明，结合两种失稳判据控制程序运算，即利用收敛性判据作为边坡失稳的判据，实现运算循环的自动化，参照塑性区贯通准则来衡量每次运算循环的步数，可使计算模拟更符合工程实际。结合“二分法”的强度折减法与极限平衡法相比，计算结果误差较小，偏于保守。此外，强度折减法与“二分法”的结合运用可明显提高计算速率，夹层1、2的安全系数求解时间分别为2046和5929s。相比FLAC3D内置强度折减法的计算时间，前者效率提高近6倍，且所求解的边坡安全系数可信度高。

Determination of Safety Factor of Rock Slope with Weak Interlayer Using Strength Reduction Technique

FLAC3D numerical simulation software and strength reduction technique were applied to determine the safety factor of rock slope with soft interlayer in a section of Changde-Zhangjiajie highway. Solution efficiency, stability criterion and other problems are discussed, related with the simulation course. The case study indicates that the convergence criterion combined with the interpenetration of the plastic zone criteria can well simulate the practical project. And the convergence criterion takes the slope failure as the indicator to achieve the automation of loop computation. At the same time, the plastic zone criterion can be used to decide the number of steps in the calculation. The calculated error of the strength reduction method can be made much smaller while combining with dichotomy, and the result tends to be more conservative and more accurate as compared to the limit equilibrium. In addition, the strength reduction method can accelerate the speed of calculation to a great degree, the calculated time for safety factor of 1 and 2 weak interlayers is 2046s and 5929s, respectively. Compared to the calculated time of the strength reduction method inside FLAC3D, the speed of calculation is six times faster, and the safety factor is also more reliable.