小浪底土石坝坝坡稳定性的概率分析

Probability analysis of the stability for Xiaolangdi earth rock-fill dam

大坝设计的主要工作之一是对其在多种运行和环境情况下的稳定性进行分析。这种分析传统上常用确定性方法。但是,有些变量如土料的强度参数、孔隙压力及其它一些有关参数的取值包含着不确定性,而这种不确定性在传统的确定性方法中不能得到处理。因此,迫切希望能利用基于解析/数值方法的概率方法来进行大坝稳定分析,以考虑这些不确定性。利用Rosenblueth法对小浪底土石坝坝坡的可靠度指标进行了分析评估。为判断小浪底土石坝的主滑面,采用了2种不同的准则(即最小安全系数指标和最小可靠度指标)。文中也指出最小安全系数滑面不一定就是主滑面,但最小安全系数滑面可以作为最小可靠度指标主滑面搜索的近似初始滑面。

One of the main work for the design of a dam is to analyze its stability under varied operations and environmental situations. Traditionally, the deterministic method is often used for analysis. However, some variables （such as strength parameters of soil material, pore pressure） and the values of some other parameters include uncertainty, and this kind of uncertainty can not be dealt with in the traditional determinitic method. So, it＇s expected to make stability analysis of the dam with the analytic or value method in order to take the uncertainty into account. This paper analyzes and evaluates the reliability index of Xiaolangdi earth rock - fill dam with the Rosenblueth method. In order to judge the main sliding surface of the earth rock - fill dam, two criteria （ minimum safety coefficient index and minimum reliability index） are adopted. It＇s also pointed out that the sliding surface of the minimum safety coefficient might not be a main sliding surface, but the sliding surface with the minimum safety coefficient can be regarded as the approximate initial sliding surface which is searched by the minimum reliability index .