| 降雨入渗条件下自嵌式挡土墙倒塌机理分析 |
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| 引用本文： | 李永华,刘一涛,叶美娇.降雨入渗条件下自嵌式挡土墙倒塌机理分析[J].中国地质灾害与防治学报,2019,30(4):76-84. |
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| 作者姓名： | 李永华 刘一涛 叶美娇 |
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| 作者单位： | 南昌大学建筑工程学院 |
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| 摘 要： | 某高校自嵌式挡土墙在暴雨入渗后多处发生坍塌,破坏形式主要表现为与挡土砌块相连的土工格栅被拉断,自嵌式挡土砌块及临近土体局部坍塌,但挡土墙后土体基本保持稳定。基于饱和-非饱和土渗流理论,分析降雨入渗情况下墙后土负孔隙水压力的分布,基于Fredlund双变量强度准则采用极限平衡法计算挡土墙稳定,结果表明:降雨入渗后回填土区域负孔隙水压力明显降低且分布较均匀,整体稳定满足要求。为分析局部坍塌原因,现场取样试验得出降雨前后墙后土体总应力强度进行有限元分析,结果表明:砌筑过程中土工格栅在自嵌式挡土砌块与砾石交界处会产生弯折,降雨入渗对土体的软化增大了格栅弯折程度及内力,在弯折段土工格栅处于复合受力状态,复合受力状态下土工格栅的抗拉强度远小于其极限抗拉强度,是导致与挡土砌块相连处格栅被拉断及临近土体局部坍塌的主要原因,设计时应特别引起重视。
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| 关 键 词： | 自嵌式挡土墙 非饱和土 孔隙水压力 局部倒塌 总应力强度 |
Analysis on the collapse mechanism of self-anchored retaining wall under rainfall infiltration |
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| LI Yonghua,LIU Yitao,YE Meijiao.Analysis on the collapse mechanism of self-anchored retaining wall under rainfall infiltration[J].The Chinese Journal of Geological Hazard and Control,2019,30(4):76-84. |
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| Authors: | LI Yonghua LIU Yitao YE Meijiao |
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| Affiliation: | (School of Architecture and Civil Engineering,Nanchang University,Nanchang,Jiangxi 330031,China) |
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| Abstract: | A self-anchored retaining wall in a university collapsed after rainfall infiltration,with the following failure modes:the geogrids connected with retaining blocks were ruptured,the self-anchored retaining blocks and adjacent soil-body collapsed,but the soil-body behind the retaining wall remained basically stable.In this paper,the saturated-unsaturated seepage theory and Fredlund’s bilinear strength criterion were used to analyze the distribution of pore water pressure after rainfall infiltration,and calculate the stability of the retaining wall,respectively.This study shows that the negative pore pressure decreases obviously and distributes evenly after rainfall infiltration,and the overall stability meets the stable requirements.Based on the total stress strength of the soil-body behind the retaining wall measured by field sampling,further FEM analysis was conducted in this study to explore the causes of local collapse.The analyzing results showed the following:the geogrids would bend at the junction of the retaining blocks and gravels during the constructing stage;the softening of the soil-body by rainfall infiltration increased the bending degree and internal force of the geogrids;and the geogrids in the bending section was in the state of compound stress,which was subjected to compound stress.The tensile strength of geogrids in combined bending stress state was much smaller than the nominal tensile strength,which was the main reason for the breakage of the geogrids at the joints of retaining blocks and the local collapse of the adjacent soil-body.Therefore,special attention should be paid to the design of geogrids. |
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| Keywords: | self-anchored retaining wall unsaturated soil pore water pressure collapse total stress strength |
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