间歇式降雨对沅麻盆地红层滑坡的影响分析  

Analysis of the Influence of Intermittent Rainfall on Red Bed Landslide in Yuanma Basin

作　　者：范文韬 贺建清[1] 李军伟 王津 王湘春 FAN Wen-tao;HE Jian-qing;LI Jun-wei;WANG Jin;WANG Xiang-chun(Hunan Province Key Laboratory of Geotechnical Engineering Stability Control and Health Monitoring,Hunan University of Science and Technology,Xiangtan,Hunan,411201,China;Natural Resources Survey Institute of Hunan Province,Changsha,Hunan,410014,China)

机构地区：[1]湖南科技大学岩土工程稳定控制与健康监测省重点实验室,湖南湘潭411201 [2]湖南省自然资源调查所,湖南长沙410014

出　　处：《建材技术与应用》2024年第1期1-7,共7页Research and Application of Building Materials

基　　金：国家自然科学基金资助项目(52078211);湖南省自然科学基金项目(2017JJ30252);湖南省自然资源厅基金资助项目(20230143DZ)。

摘　　要：沅麻盆地红层边坡具有岩层倾角小和所处边坡坡角小的特点,天然状态下处于相对稳定状态。水对红砂岩的力学性质有着很大的影响,降雨的入渗会引起边坡内土层饱和重度上升和基质吸力下降,在裂隙中产生的水头会对坡体有平推力。为了研究降雨对边坡稳定性的时间-空间效应,通过现场勘察沅麻盆地地区已有滑坡,采取数值模拟等手段进行定性和定量分析,还原大华坪滑坡的全过程,并对不同强度下前期降雨和后期降雨对边坡的作用进行对比分析。结果表明:前期降雨影响体现在入渗后引起的基质吸力降低和裂隙中水压不断上升,安全系数不断下降但未能达到滑坡临界值,停雨后边坡安全系数的回升具有滞后性,前期降雨量越小滞后性越明显;后期降雨影响体现在降雨量越大,更容易形成表面渗流,增大了下滑力。如果原有裂隙中存在积水,则坡体停雨阶段的安全系数变化比较缓慢。The red bed slope of Yuanma Basin has the characteristics of small rock dip angle and small side slope angle,and it is in a relatively stable state in natural state.Water has a great influence on the mechanical properties of red sandstone.Rainfall infiltration will cause the saturation of soil layer inside the slope to increase,the matrix suction to decrease,and the water head generated in the crack will have a flat thrust on the slope.In order to study the temporal and spatial effects of rainfall on slope stability,the whole process of Dahuaping landslide was reconstructed through field investigation of existing landslides in Yuanma Basin and quantitative and qualitative analysis was carried out by means of numerical simulation,and the effects of early and late rainfall on slope under different intensification were compared and analyzed.The results show that the influence of rainfall in the early stage is reflected in the reduction of matrix suction caused by infiltration,the continuous rise of water pressure in cracks,and the continuous decline of safety factor but failing to reach the critical value of landslide.The recovery of safety factor of slope after rain stop has a lag,and the lag is more obvious with the smaller the rainfall in the early stage.The influence of late rainfall is reflected in that the higher the rainfall,the more easily the surface seepage is formed,and the sliding force is increased.If there is water in the original fissure,then the safety factor of slope during the rain stop stage changes slowly.

关 键 词：红层软岩滑坡 降雨模式 Geostudio数值分析 

分 类 号：P642.22[天文地球—工程地质学]