考虑间断级配影响的土石混合体水力侵蚀分异机理  

Hydraulic erosion differentiation mechanism of soil⁃rock mixture considering the effect of discontinuous gradation

作　　者：李诗琪 杨忠平[1,2,3] 刘浩宇 高宇豪[1,2,3] 刘新荣 Li Shiqi;Yang Zhongping;Liu Haoyu;Gao Yuhao;Liu Xinrong(Chongqing University,Chongqing 400045,China;Key Laboratory of New Tech-nology for Construction of Cities in Mountain Area of Ministry of Education,Chongqing 400045,China;National Joint Engineering Research Center of Geohazards Prevention in Reservoir Area(Chongqing),Chongqing 400045,China)

机构地区：[1]重庆大学,重庆400045 [2]山地城镇建设与新技术教育部重点实验室,重庆400045 [3]库区环境地质灾害防治国家地方联合工程研究中心,重庆400045

出　　处：《土木工程学报》2024年第10期125-134,共10页China Civil Engineering Journal

基　　金：国家重点研发计划项目(2021YFB3901402);重庆市自然科学基金(cstc2021jcyj-msxmX0558)。

摘　　要：近年来,堆积体滑坡频发,已成为西南地区最典型的滑坡类型。研究表明,超过50%的库区堆积体滑坡诱因为水力侵蚀,因此降雨、岸坡侵蚀、波浪掏蚀成为库区滑坡灾害防治重点关注的问题。同时,土石混合体自身的间断级配会对其水力特性造成明显影响,进而导致水力侵蚀作用下堆积体内部的颗粒运移规律具有独特性。采用自主研发的土石混合体渗透侵蚀试验装置,模拟土石混合体内部细观侵蚀过程,阐明其侵蚀分异机理,揭示间断级配的影响。结果表明:土石混合体侵蚀过程主要分为快速侵蚀、侵蚀减缓、稳定渗流3个阶段,超过60%的侵蚀在快速侵蚀阶段完成;与良好级配试样相比,间断级配试样的侵蚀量更大,初始侵蚀更剧烈,快速侵蚀阶段更短暂;间断级配对土石混合体水力侵蚀分异的影响同样明显,细颗粒缺失结构的细颗粒尺寸单一,不易堵塞渗流通道,渗透系数高于良好级配试样,且最大渗透系数与最终渗透系数差异较小;中颗粒缺失结构因大量细颗粒下沉堵塞渗流通道导致渗透系数明显低于良好级配试样;粗颗粒缺失结构内部块石承载骨架结构差,孔隙大,易引发大块石局部破坏,渗透系数高于良好级配试样。Debris flow events have become increasingly frequent and represent the predominant type of landslide in the southwest region of China.The research shows that more than 50%of reservoir landslides are caused by hydraulic erosion,so rainfall,bank slope erosion and wave erosion have become the key issues in the prevention and control of reservoir landslide disasters.Meanwhile,the hydraulic characteristics of the soil⁃rock mixture are significantly influenced by its discontinuous gradation,resulting in unique particle migration pattern within the accumulation body under the influence of hydraulic erosion.A self⁃designed apparatus was employed to simulate the micro⁃scale erosion process in soil⁃rock mixtures,elucidate the underlying mechanisms of erosion differentiation and reveal the impact of discontinuous particle size distribution.The findings revealed a three⁃stage erosion process in the soil⁃rock mixture:rapid erosion,erosion deceleration,and stable seepage,with over 60%of the erosion taking place during the rapid erosion stage.Discontinuous graded samples exhibited greater erosion volume,more pronounced initial erosion,and a shorter duration of the rapid erosion stage,compared to the well⁃graded counterparts.Moreover,discontinuous particle size distribution significantly influenced the differentiation of hydraulic erosion in the soil⁃rock mixture.Samples lacking fine particles exhibited a uniform size among the remaining particles,resulting in reduced blockage of seepage channels,and the permeability coefficients of the samples were higher than those of well⁃graded samples,with lesser disparity between the maximum and final coefficients.Conversely,in samples lacking intermediate⁃sized particles,the substantial settling of fine particles led to pronounced blockage of seepage channels,significantly reducing the permeability coefficient in comparison to well⁃graded samples.Samples lacking coarse particles experienced internal rock fragments that acted as bearing skeleton structures,featuring l

关 键 词：土石混合体 渗透侵蚀 结构分异 颗粒运移 间断级配 

分 类 号：TU431[建筑科学—岩土工程]