考虑渗流时滞及参数不确定性的土坝坝坡失稳概率分析

摘要

In view of the problem of slope stability of earth-rock dam under complex seepage field and uneven distribution of dam shell material with non constant hydraulic boundary,a new instability probability analysis method for dam slope with uncertain flow time delay and parameter uncertainty is proposed.Based on Van Genuchten seepage model,shear strength theory and Bishop method,the analytical formula and reliability function of the stability and safety coefficient of non-homogeneous dam slope are derived by combining with the time-dependent characteristics of seepage field and its hydraulic boundary.Based on GeoStudio platform and Kriging model,a non-invasive stochastic finite element model for dam slope stability and reliability of earth-rock dam is established and related calculation programs are developed.The engineering example analysis shows that the results of above method are closer to the actual operation status of dam than the method in specification.Compared with Monte Carlo method,proposed method has obvious advantages in terms of calculation time and convergence.The proposed method can also be applied to analyze the stability reliability of complex slope under different hydraulic boundary conditions.%针对非恒定水力边界下土石坝体内复杂渗流场和坝壳物料不均匀分布对其坝坡稳定失效概率问题,提出了一种考虑土石坝渗流时滞及参数不确定性的坝坡失稳概率分析方法.综合运用Van Genuchten渗流模型与抗剪强度理论及毕肖普法,结合坝体内部渗流场与渗流的时滞相关特性,给出了基于均质坝坡稳定安全系数解析式与可靠性功能函数,利用GeoStudio平台融合Kriging模型优势,建立了土石坝坝坡稳定可靠度非侵入式随机有限元模型,并研制了其相关实施程序.工程实例分析表明,该方法较规范方法更接近大坝服役真实状况,相比蒙特卡洛法在其计算工时及收敛等方面优势明显,该方法亦可推广应用于不同水力边界条件下的复杂边坡稳定可靠度分析.