摘要
由于砂土特殊的物理力学特性,砂土岸坡的失稳破坏过程与一般黏性土岸坡存在明显差别。以厚层砂土型河道岸坡为对象,研究不同降雨强度和岸坡坡比下的砂土岸坡变形破坏过程。共设计5组室内物理模型试验,每组试验均埋设水分计、微型孔压计、引线式温度计,并利用高精度摄像机记录岸坡变形破坏的全过程。试验结果显示:随含水率增大,非饱和砂土黏聚力呈先增后减的趋势,并具有明显的峰值,内摩擦角呈减小趋势;不同雨强及坡比情况下,砂土岸坡的变形破坏机制不同;短历时降雨会在坡体表层形成饱和区,阻止雨水的入渗,砂土层不同深度水分运移各异,雨水入渗并非单一的垂直入渗;岸坡侵蚀破坏在雨水冲刷、降雨入渗及重力侵蚀的耦合作用下发生。试验能够真实反映复杂工况下砂土岸坡的冲刷特性与坍塌破坏全过程,可为多因素共同作用下岸坡稳定分析理论与方法的建立提供参考。
Due to its special physical and mechanical characteristics,the destabilization failure process of sandy soil bank slope is significantly different from that of general clay soil bank slope.In this experiment,the deformation and failure process of thick sandy soil type river bank slope under different rainfall intensities and bank slope ratios was studied.A total of five sets of indoor physical model tests were designed,and each set of tests was conducted with buried moisture meter,micro pore pressure meter and lead thermometer for measurement,and the whole process of bank deformation and damage was recorded by high precision camera.The test results show that the cohesive force of unsaturated sandy soil tends to increase and then decrease with increasing water content,and has an obvious peak value,and the angle of internal friction tends to decrease.The deformation and damage of sandy soil bank slope under different rainfall intensities and slope ratios show two different mechanisms.The short-duration rainfall will form a saturation zone on the surface layer of the slope,which prevents the infiltration of rainwater,and the water transport varies at different depths of the sandy soil layer,so the infiltration path of rainwater is not a single vertical infiltration.The bank erosion failure occurs under the coupling effect of rainfall scouring,rainfall infiltration and gravity erosion.This study can truly reflect the scour characteristics and collapse failure process of sandy slopes under complex conditions,and provide a reliable reference for establishing the theory and method of slope stability analysis under the joint action of multiple factors.
作者
吴冰
张桂荣
池诚
孔洋
李登华
丁勇
WU Bing;ZHANG Guirong;CHI Cheng;KONG Yang;LI Denghua;DING Yong(School of Science,Nanjing University of Science and Technology,Nanjing 210094,China;Nanjing Hydraulic Research Institute,Nanjing 210029,China;College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China)
出处
《水利水运工程学报》
CSCD
北大核心
2023年第5期113-122,共10页
Hydro-Science and Engineering
基金
国家自然科学基金面上项目(51979174)
国家自然科学基金长江水科学联合基金项目(U2240221)。
关键词
砂土岸坡
降雨冲刷
物理模型试验
变形破坏
sand bank slope
rainfall erosion
physical model test
deformation failure
作者简介
吴冰(1998-),男,江苏徐州人,硕士研究生,主要从事岩土力学试验研究。E-mail:wubing0116@163.com;通信作者:张桂荣,E-mail:grzhang@nhri.cn。
