基于FLAC^(3D)的强度折减法程序改进研究

Improvement of strength reduction program based on FLAC^(3D)

传统的FLAC^(3D)自编强度折减法程序基于抗剪强度折减技术和二分法来计算边坡安全系数。但每次重复迭代过程(折减强度)程序都需对模型初始应力重新计算。迭代过程重复越多,无谓的耗时越多且初始应力值在第一次迭代后产生变化。针对不足,在介绍了常见边坡稳定性分析方法和关于强度折减法背景知识后,用内嵌于FLAC^(3D)的编程语言FISH语言对其改进。主要过程为:用FISH语言的函数将算得初始应力写入文件;通过函数和赋值功能将文件中初始应力依次赋值给模型分块;用上面语句代替FLAC^(3D)自编强度折减法程序中初始应力计算部分。改进FLAC^(3D)自编强度折减法程序省去每次迭代中重新计算初始应力且保证初始应力在整个迭代运算中一致。对比三种常见的用FLAC^(3D)求解安全系数方法,改进FLAC^(3D)自编强度折减法程序耗时最短,计算结果精确。对于模型和初始应力条件复杂的边坡用改进自编强度折减法程序求解边坡安全系数可节省大量时步和真实运算时间。

Traditional self-made strength reduction program is based on bisection method and strength reduction technique to analyze slope stability. However, this method has defects：initial stress changes after the first iterative operation （strength reduction）, and in each iteration, initial stress must be recalculated, which is unnecessary and time-consuming. In order to avoid the defects, we introduced common slope stability analyzing methods and back- ground information about strength reduction method, then we used FISH, a programming language embedded within FLAC3D to improve the strength reduction program. Input the initial stress into the file with FISH ＇ s input - output functions, assign each initial stress to the slope model, and replace the initial stress calculation part in the self- made strength reduction program with the statement above. The improved strength reduction program omitted recalculating initial stress in each iteration, and guaranteed the consistency of initial stress in the whole iterative operation. Compared with the other three common methods to obtain the factor of safety, the improved strength reduction program was the least time-consuming and most accurate method. For slope models with complex initial stress conditions, using the improved strength reduction program to obtain the factor of safety could save many time steps and actual operation time.