高土石不过水围堰边坡失稳风险分析

RISK ANALYSIS OF SLOPE INSTABILITY OF HIGH EARTH NO-OVERFLOW-COFFERDAM

高土石不过水围堰边坡失稳导致溃堰造成的损失巨大,对其进行风险分析有重要意义。综合考虑水文、水力及填筑土石料力学参数的不确定性,构建基于安全系数的高土石不过水围堰边坡失稳风险数学模型。考虑最危险滑动面位置每次仿真模拟的变动性,采用分层–LHS抽样方法获取填筑土石料随机参数样本以提高抽样效率。然后,利用K-S检验原理判断边坡安全系数可接受的分布类型,利用拟合优度指标确定最优概率分布,继而给出风险模型求解的计算过程。最后,对西南地区某大型水电工程进行计算分析。结果表明,所提方法有效地提高风险计算的效率,且概率分布拟合效果良好,使得风险率得以准确合理的估计,为高土石不过水围堰边坡失稳风险分析提供了新的思路和方法。

Cofferdam break caused by slope instability of high earth no-overflow-cofferdam can make a huge loss,there is important significance to carry out risk analysis. The uncertainty of hydrological,hydraulic and mechanical parameters of filling soil-stone were comprehensively considered to establish the slope instability risk model of high earth no-overflow-cofferdam based on the safety factor. Considering the change of critical sliding surface position in each simulation,layered-LHS sampling method was used to obtain the filling soil stone random sample in order to improve the sampling efficiency. Then,K-S test principle was used to judge the distribution types of the slope safety factor,and fitting optimization index was adopted to determine the optimal probability distribution,then the calculating process of risk model was given. Finally,a large hydropower project in the Southwest of China was calculated and analyzed. The results indicate that the proposed method effectively improves the efficiency of risk calculation,and the fitting effect of probability distribution is satisfactory,so that the risk can be estimated accurately and rationally,this paper provides a new idea and method for risk analysis of slope instability of high earth no-overflow-cofferdam.