不同雨强下非饱和砂性坡体破坏形式的含水特性研究  

Research on moisture content characteristics of unsaturated sandy slope failure forms under different rainfall intensities

作　　者：曲立强 杜强 QU Liqiang;DU Qiang(School of Civil Engineering,Inner Mongolia University of Technology,Hohhot O10051,China;Key Laboratory of University of Geological Hazards and Geotechnical Engineering Defense in Sandy and Drought Regions,Inner Mongolia Autonomous,Hohhot O10051,China;Department of Geotechnical Engineering,Tongiji University,Shanghai 200092,China)

机构地区：[1]内蒙古工业大学土木工程学院,内蒙古呼和浩特010051 [2]沙旱区地质灾害与岩土工程防御自治区高等学校重点实验室,内蒙古呼和浩特010051 [3]同济大学地下建筑与工程系,上海200092

出　　处：《武汉大学学报（工学版）》2024年第3期329-337,共9页Engineering Journal of Wuhan University

基　　金：内蒙古自治区自然科学基金(编号:2022LHMS05010);自治区直属高校基本科研业务费项目(编号:JY20220096);内蒙古工业大学科学研究项目(编号:BS202044)。

摘　　要：为了研究不同降雨强度下非饱和砂土边坡内部含水特性,探究破坏含水率与破坏形式的关系及坡体破坏的水土作用机理,通过室内模型试验研究了在不同降雨强度下粗砂和细砂2种坡体内部含水率的变化规律及前期降雨对坡体破坏的影响,并基于土水特征曲线分析降雨诱发坡体破坏的内部机理。试验结果表明:在降雨过程中,含水率变化存在3个阶段:Ⅰ阶段,含水率变化近似呈线性增长;Ⅱ阶段,含水率增长趋于平缓;Ⅲ阶段,在高雨强下,坡体破坏前含水率快速增长。不同降雨强度下坡体破坏形式不同,破坏含水率亦不同:当坡体发生坡脚流失时,破坏含水率为12%左右;当坡体发生分层滑动时,破坏含水率为13%~18%;当坡体发生整体流滑时,破坏含水率为20%左右。但无论发生何种破坏,在破坏时,坡体均未达到饱和状态。不同初始含水率也会影响坡体破坏形式和破坏时间,初始含水率越高,坡体破坏规模越大,发生破坏所需的时间越少。随着坡体含水率的增加,坡体的基质吸力减少,抗剪强度降低,下滑力大于抗滑力,坡体最终发生破坏。In order to study the internal moisture content characteristics of unsaturated sandy soil slopes under different rainfall intensities and explore the relationship between failure moisture content and failure forms and the soil-water interaction mechanism of slope failure,the change laws of the internal water content of coarse sand and fine sand slopes under different rainfall intensities and the influence of the previous rainfall on slope failure are studied through laboratory model tests.The internal mechanism of the rainfall-induced slope failure is analyzed based on soil-water characteristic curve.The test results show that there are three stages of moisture content change in the process of rainfall.In stage I,the moisture content increases approximately linearly.In stage II,the growth of moisture content tends to be gentle.In stage II,under high rainfall intensity,the moisture content of slope body increases rapidly before slope failure.Under different rainfall intensities,the failure forms of the slope are different,and the failure moisture contents are also different.When the slope toe loss occurs,the failure moisture content is about 12%.When the slope slides in layers,the failure moisture content is 13%~18%.When the overall flow-slip occurs in the slope,the failure moisture content is about 20%.No matter what kind of damage occurs,the slope does not reach the saturation state.Different initial moisture content also affects the failure form and failure time of the slope.The higher the initial water content,the larger the failure scale of slope and the less time required for failure.As the moisture content of the slope increases,the matrix suction of the slope decreases,the shear strength decreases,the sliding force is greater than the anti-sliding force,and the slope eventually fails.

关 键 词：含水特性 破坏形式 基质吸力 砂土边坡 土水特征曲线 

分 类 号：TU411.93[建筑科学—岩土工程]