降雨冲刷下黄土堆填边坡土水参数变化规律  

Change characteristics of soil and water parameters of loess landfill slopes during rainfall scouring

作　　者：张座雄 刘兴荣[1] 王之君[3] 黄金燕 马彦杰 ZHANG Zuoxiong;LIU Xingrong;WANG Zhijun;HUANG Jinyan;MA Yanjie(Geological Hazards Prevention Institute,Gansu Academy of Sciences,Lanzhou 730000,China;China Construction Fourth Engineering Bureau Company Limited,Guangzhou 510665,China;School of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]甘肃省科学院地质自然灾害防治研究所,兰州730000 [2]中国建筑第四工程局有限公司,广州510665 [3]兰州理工大学能源与动力工程学院,兰州730050

出　　处：《农业工程学报》2023年第23期75-84,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：第二次青藏高原综合科学考察研究资助项目(2019QZKK0903);甘肃省科技重大专项(23ZDFA009);甘肃省科学院重点科技研发项目(2023ZDYF-03);甘肃省重点研发计划项目(20YF8ND141)。

摘　　要：黄土区城市工程建设产生了大量黄土堆填边坡,因其结构松散,缺乏必要防护,水土流失严重。该研究基于野外调查,设计室内堆填边坡降雨冲刷模型试验,分析其侵蚀破坏过程中含水率和基质吸力的响应变化规律,结合水土动力学原理,分析了降雨切沟侵蚀阶段沟坡坍塌破坏机理,并揭示了坡度对侵蚀产沙量的影响。结果表明:1)随坡度增大,坡顶含水率饱和速率加快,边坡基质吸力响应速率先增后减,且在40°范围内响应速率最快,在此坡度附近需更加注重坡面防护和坡脚排水。2)切沟侵蚀阶段,沟坡坍塌破坏为水力-重力复合侵蚀过程,且坡度越大,越容易达到临界破裂角,沟坡重力侵蚀现象越普遍。3)黄土堆填边坡在极端降雨条件下,其临界坡度在41°附近。该研究成果可为黄土区工程堆积体的地质灾害防治及水土流失综合治理提供理论支持。In recent years,with China's"One Belt,One Road""Western Development"and other national strategies vigorously promoted,the Loess Plateau's urbanization process accelerated,the demand for urban land increased,but the Loess area is dominated by gullies and hills,the terrain is fragmented,and the ditches are longitudinal and transverse,which seriously restricts the local urban construction and economic development,local urban construction and economic development.In order to expand the urban space,many cities have carried out the project of leveling hills to create land,but during the implementation of the project,loess dumps are usually piled up along the gullies,forming a larger number and area of loess landfill slopes.Therefore,in order to investigate the variation rules of soil and water parameters in different slopes of loess landfill slopes during extreme rainfall,this study,based on the field investigation,took the typical loess landfill-Jianshui gully watershed in Lanzhou urban area(an important node city of Loess Plateau)as an example to carry out the simulation test of indoor rainfall,with the slope gradient of the side slopes set at 25°,30°,35°,40°,45°,and the water content and substrate suction rate of the side slopes were recorded at different parts of the side slopes in the process of rainfall.During the rainfall process,the water content and matrix suction change data were recorded at different parts of the slope.In order to analyze the damage mechanism of cut-gully slumping of landfill loess slopes,the theory of unsaturated soil shear strength was coupled with the gravity erosion model of loess gully slopes,and the influence of slope gradient on the erosion and sediment yield of slopes was further analyzed.The results showed that:1)the development process of rainfall erosion on the loess slope of landfill was divided into three stages(spattering and sheet erosion stage;rill erosion stage;and gully-cutting erosion and collapse damage stage),in which the rill erosion stage lasted for the longest ti

关 键 词：边坡 降雨 侵蚀 黄土堆填 土水参数 切沟 临界坡度 

分 类 号：P628.8[天文地球—地质矿产勘探]