摘要:
利用FLAC3D的内置fish语言基于强度折剪法对其进行了二次开发,编制了滑坡体安全系数计算程序。结合工程实例,将这种方法应用于已知滑动面条件下的滑坡稳定性分析中,得到滑坡体天然状况下的二维、三维安全系数,同时对内摩擦角和粘聚力参数进行了敏感性分析,对比并分析了传统极限平衡法和FLAC3D强度折减法的计算结果,得出以下结论:①利用二维FLAC3D强度折减法计算的滑坡安全系数略高于传统极限平衡法;②利用三维FLAC3D强度折减法所得滑坡安全系数略高于二维FLAC3D的计算结果;③滑坡安全系数都是随着内摩擦角和粘聚力的增大而增大,其中内摩擦角和粘聚力的变化对三维FLAC3D强度折减法比二维求解安全系数影响更大一些。然后模拟了滑体在天然条件下处于极限平衡状态的滑动方向,并得出天然状况下滑坡整体基本稳定,仅滑坡后缘可能出现局部失稳的分析结果。同时探讨了三维FLAC3D模型建立过程中滑坡外围不动体及滑带以下基岩所取范围大小、网格剖分粗细程度对计算安全系数的影响。
Abstract:
Firstly,the safety factor calculation program is compiled with fish language embedded within FLAC~ 3D for the second development based on the strength reduction method. With a case study, this method is applied to 3D analysis on landslide stability with confirmed sliding zone in this paper. Then computation is completed for its 2D and 3D safety factor in natural condition. At the same time, inversions of friction angle and cohesion parameter are analyzed. Comparison of calculation results with limit equilibrium method and FLAC~ 3D is also analyzed. The results indicates: ①The safety factor computed with strength reduction FLAC~ 3D is a little bigger than limit equilibrium method. ②The calculated result of 3D strength reduction FLAC~ 3D is ratherish larger than 2D because of three dimensional effect. ③The increasing cohesion and internal friction angle results in a increase of the safety factor with different methods, furthermore, the influences to 3D strength reduction FLAC~ 3D is a litter more significant than 2D with the cohesion and internal friction angle. Secondly, simulation is made for the sliding direction under limit equilibrium situation, and the analysis result is obtained as that the entire landslide is basically stable with probably local failure. Finally, influencing factors are discussed when building the FLAC~ 3D model, such as the range of peripheral rock mass and bedrock under sliding zone and the mesh subdivision of the model.
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