边坡稳定性因素敏感性分析及可靠度研究

Sensitivity Analysis and Reliability Study on Impact Factors of Slope Stability

结合定值法和不确定方法,研究了边坡稳定性因素的敏感性及参数对可靠度的影响规律。在GeoStudio有限元应力法的基础上,提出一种新的耦合分析方法对均质边坡进行敏感性分析;根据定值法分析结果,采用蒙特卡罗法研究了不同随机变量的变异性和强度参数相关性对可靠度的影响规律。结果表明,边坡稳定性影响因素的敏感性顺序依次为:粘聚力、内摩擦角、坡高、容重和坡角。可靠度指标和失效概率随变异系数及c-φ相关系数的变化呈现规律性。假设参数变异性一定时,将敏感性较大的因素作为随机变量,计算得到的可靠度指标较小,失效概率较大。因此在可靠性分析之前进行因素的敏感性分析,再根据参数变异性及相关性对可靠指标的影响规律选取随机变量,分析结果更合理。

Combining the （ixed value method and the uncertain method, the sensitivity of slope stability factors and the influence of parameters on the reliability were studied. A new coupling analysis method was proposed to analyze the sensitivity of slope based on finite element stress method-GeoStudio. Then, according to the result of the fixed value method, Monte Carlo Method was used to research the influence of the variability of different random variables and the correlation of strength parameters on the reliability. The results domenstrated that the sensitivity of impact factors of slope stability was in the sequence from cohe- sive force, internal friction angle, slope height, soil density to slope angle. And, with the change of variation coefficient and c- φ correlation, the reliability index and failure probability varied regularly. When the parameter variability was certain, the grea- ter sensitivity factors were taked as random variables for calculating, which obtained slightly low reliability indexes and slightly high failure probabilities. Therefore, it was likely to get more reasonable analysis results, making factors sensitivity analysis before the reliability analysis and then choosing the random variables based on the influence of parameter variability and c-φ cor- relation on reliability indexes.