A catastrophic landslide of construction waste occurred at the Hong'aocun Landfill in Shenzhen of Guangdong Province at 11:40 am on December 20,2015,with an area of 38.5 × 104 m2 covered by soil.Analyses of previous researches on the characteristics and mechanism of the landslide and data of field investigation indicate that the reason of the hazard is that the weak sliding interlayers,which were formed by the saturated clay at the bottom of the landfill,caused the global instability of landslide.In this study,constant permeability test and physical simulation test were conducted to investigate the permeability and the reason of the saturated bottom clay.The experimental results show that the hydraulic conductivity of the infilling material is much higher than the normal clay.What's more,hydraulic conductivity has an exponential relationship with the original moisture content and dry density of infilling,with the correlation coefficients larger than 0.96 and 0.925,respectively.The hydraulic conductivity of infilling is anisotropic,showing a higher permeability in the vertical direction than in the horizontal direction.%2015年12月20日11时40分许,广东省深圳市光明新区红坳村渣土临时受纳场发生一起渣土堆填物特大滑坡事故,滑坡覆盖面积约38.5×104 m2.根据前人对滑坡特征与成因机制的分析成果并结合现场调查可知,堆填物底部饱水形成软弱滑动层是滑坡失稳破坏的主要原因.为了对滑坡堆填物底部饱水的原因进行分析,文章对滑坡土体的渗透性进行了常水头渗透试验与物理模拟试验研究.研究结果表明:深圳“12·20”滑坡土体渗透系数明显大于一般黏土;渗透系数随着初始含水率和干密度的增大均呈指数函数关系,且相关系数分别大于0.96与0.925;在后缘注水的情况下,土体的垂直渗透性大于水平渗透性.
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