强度折减DDA法及其在边坡稳定分析中的应用

 在自行研制的非连续变形分析程序中实现自动强度折减法以模拟边坡的稳定性和安全系数。针对强度折减有限元法收敛标准的不确定性，通过分析滑块在边坡上的稳定性，提出以边坡滑移位移与强度折减系数曲线的最大曲率所对应的折减系数为边坡安全系数的判别标准，该判别标准克服了“位移突变准则”不准确的缺点；并基于该判别标准，分析水库岩体边坡的稳定性并得到岩体边坡安全系数随库水位变化的规律；最后对小湾某高边坡进行开挖模拟及开挖后边坡的稳定性进行计算分析。

DDA WITH STRENGTH REDUCTION TECHNIQUE AND ITS APPLICATION TO STABILITY ANALYSIS OF ROCK SLOPE

An extension version of discontinuous deformation analysis(DDA) is presented. In order to calculate the safety factor of a slope，the strength reduction technique is accomplished in the self-developed DDA program. In the extended DDA method，the maximal curvature of the relationship curve of the displacement and the reduced factor is proposed as the failure criterion in the slope stability analysis，which overcomes the drawbacks of the criterion of displacement dramatic increasing. And then，the stability of a rock slope during the falling of the reservoir water level is analyzed based on the failure criterion. The relationship between the safety factor of the slope stability and the speed of the falling of the reservoir water level is obtained. Finally，the excavation sequence of the high slope of Xiaowan Hydraulic Project is simulated using the program and the stability of the excavated slope is analyzed.