正反粒序结构条件下滑坡堰塞坝破坏模式研究  

A study of the failure mode of landslide dam under the structural conditions of positive and reverse grain sequences

作　　者：吴茂林 罗刚 高延超[2] 陈西南 翟新乐 WU Maolin;LUO Gang;GAO Yanchao;CHEN Xi’nan;ZHAI Xinle(Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Chengdu Geological Survey Center of China Geological Survey,Chengdu,Sichuan 610081,China)

机构地区：[1]西南交通大学地球科学与环境工程学院,四川成都610031 [2]中国地质调查局成都地质调查中心,四川成都610081

出　　处：《水文地质工程地质》2022年第6期124-132,共9页Hydrogeology & Engineering Geology

基　　金：国家重点研发计划项目(2018YFC1505404);四川省科技厅科技计划项目(2021YJ0033);四川省自然资源科研项目(Kj-2022-29);自然科学基金青年基金项目(42107155)。

摘　　要：滑坡堰塞坝是大型滑坡堆积体堵塞河道形成的土石坝。正、反粒序结构作为大型远程滑坡所特有的2种具有显著差异的地质结构特征,2种情况下坝体的破坏模式差异及稳定性影响因素亟需试验研究。文章通过室内水槽物理模型实验,对比不同粒径、不同结构的滑坡堰塞坝坝体的破坏过程差异,探究了正、反粒序结构条件下堰塞坝的稳定性差异、破坏模式及影响因素。研究结果表明:(1)堰塞坝破坏模式的变化取决于浸润线在下游坡面的出露位置,相比上游水位有一定的延迟性;(2)正、反粒序堰塞坝的破坏模式取决于坡体渗流与下游坡面临界起动坡降的关系;(3)细砂层的位置分布,不同埋深细砂层的起动临界坡降差异和细砂与中粗砂的孔隙率差异是造成正、反粒序坝体破坏差异的主要原因。该研究成果可为大型滑坡堰塞坝的防灾减灾提供理论指导。Landslide dam is an earth-rock dam formed by the deposits of large river-blocking landslides.Because the unique geological structure characteristics of large-scale long-runout landslides under the conditions of positive and reverse grain sequence structures differ significantly,the experimental study of the differences of failure modes and influencing factors of landslide stability of dams under these two conditions are urgently needed.In this paper,the failure process differences of landslide dams with different particle sizes and different structures are compared through indoor water tank model experiments,and the stability differences,failure mechanism and influencing factors of landslide dams with positive and reverse grain sequence structures are explored.The results show that(1)The change of failure mode of the landslide dam depends on the position where the phreatic line is exposed on the downstream slope,which has a certain delay compared with the upstream water level;(2)The failure modes of landslide dams with positive and reverse grain sequence structures depend on the relationship between slope seepage and startup critical gradient of downstream slope.(3)The location distribution of fine sand layer,the difference of startup critical gradients of fine sand layers at different depths and the difference of porosities between fine sand and medium coarse sand are the main reasons for the difference in the failures of dams with positive and reverse sequences.The research results can provide the theoretical guidance for the disaster prevention and mitigation of large landslide dams.

关 键 词：滑坡堰塞坝 粒序结构 破坏模式 起动临界坡降 物理模型试验 

分 类 号：P642.22[天文地球—工程地质学]