建立小寨滑坡水文地质模型,模拟其在不同降雨条件下的渗流场分布及稳定性变化.结果表明,该类型滑坡的失稳演化过程主要分为上覆Q4 el+dl堆积阶段、接触带泥岩富水风化阶段和风化带富水软化阶段,风化带富水软化程度与滑体的高渗透性和滑床的隔水特性密切相关,是滑坡失稳破坏的决定性因素;滑坡的发生是因地表降雨下渗受阻,在上覆堆积层及下伏泥岩层间形成富水带,富水加速泥岩风化,并在坡体内形成强风化泥岩软弱层,随地质过程持续,泥岩强风化层逐渐加厚形成软弱带,在极端暴雨气候条件下,软弱带发生蠕变,地表开裂,滑坡形成.%A Xiaozhai landslide numerical model is established by Geostudio software,which is then used to study the stability and seepage characteristics of a landslide at different rainfall conditions and stages.The results show that:the destabilization process of this landslide can be divided into three stages.In the first,Qe4l+ d1 accumulates;in the second,contact zone (stratum between mudstone and quaternary eluvium) weathers through meeting with water;in the last,the weathered zone is softened and thickened under the humid environment.The formation and development of the softened weathered zone is closely related to highly permeable slide mass and low-permeability slip-bed that is the determining factor of a landslide;The reason a landslide is triggered can be ascribed to low permeability of mudstone,which prevents rainwater infiltration and promotes rainwater enrichment in contact zone.As the rainwater enriches,the weathering of mudstone accelerates and forms a highly weathered weak bed layer.After a severe rainstorm,the weak zone will creep and a landslide happen.
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