考虑参数变异性的土石坝渗透破坏概率分析

为合理考虑土体参数变异性对土石坝渗透破坏概率的影响，本文编写了基于GEOSTUDIO 与MATLAB 之间的渗流有限元计算及可靠度分析的接口实现程序，并以一实际土石坝工程为例验证了提出方法的有效性，探讨了库水位骤降条件下坝体材料渗透系数以及土水特征曲线模型参数的变异性对土石坝渗透破坏概率的影响。结果表明：库水位上升对土石坝渗透稳定很不利，库水位从正常蓄水位工况上升至校核洪水位工况，土石坝渗透破坏概率增加近两倍。受坝体材料基质吸力的作用，库水位骤降会导致坝体发生逆向渗流，土石坝渗透破坏概率到达某一时刻后会急剧增加，然后直至坝体内孔隙水压力得到充分消散才下降并趋于某一稳定值。

英文摘要:

In order to reasonably consider the effects of soil parameters variability on the probability of seepage failure for embankment dams，this paper compiles the interface implementation procedure between the seepage finite element analysis and reliability analysis of embankment dams based on GEOSTUDIO and MATLAB. A real embankment dam is investigated as an example to validate the effectiveness of the proposed approach. The influence of the variability of the hydraulic conductivity of dam materials and the fitting parameters of soil water characteristic curves on the probability of seepage failure under the rapid drawdown of reservoir water level is discussed. The results indicate that the rise of reservoir water level adversely affects the slope stability of embankment dam. The probability of seepage failure increases by nearly twice when the water level rises from the normal storage level to the spillway design flood level. The backward seepage in the dam body occurs with the rapid drawdown of reservoir water level，influenced by the matrix suction of dam material. The probability of seepage failure for the embankment dam increases sharply once it reaches a certain moment，and then it falls to a stable value until the pore water pressure is fully dissipated.

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