降雨作用下砂土边坡失稳破坏触发机制宏细观研究  

Macro and micro study on the failure triggering mechanism of sandy soil slopes due to rainfall

作　　者：宋享桦 肖衡林[2] 倪化勇 谭勇 SONG Xiang-hua;XIAO Heng-lin;NI Hua-yong;TAN Yong(Technology Innovation Center for Risk Prevention and Mitigation of Geohazard,Ministry of Natural Resources,Chengdu,Sichuan 611734,China;Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes,Ministry of Education,Hubei University of Technology,Wuhan,Hubei 430068,China;School of Civil Engineering and Architecture,University of Jinan,Jinan,Shandong 250022,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]自然资源部地质灾害风险防控工程技术创新中心,四川成都611734 [2]湖北工业大学河湖智慧健康感知与生态修复教育部重点实验室,湖北武汉430068 [3]济南大学土木建筑学院,山东济南250022 [4]同济大学土木工程学院,上海200092

出　　处：《岩土力学》2025年第3期969-979,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42177179,No.42402278);山东省自然科学基金青年项目(No.ZR2023QD168);河湖健康智慧感知与生态修复教育部重点实验室开放研究基金项目(No.HGKFZP002);自然资源部地质灾害风险防控工程技术创新中心开放课题(No.TICRPM-2023-05);山东省高等学校青创科技支持计划项目(No.TJY2303)。

摘　　要：降雨诱发强渗透性土质边坡失稳破坏通常始发于坡脚部位,但其触发机制一直尚未明晰。通过开展降雨边坡模型试验,并结合计算流体力学-离散元(computational fluid dynamics-discrete element method,简称CFD-DEM)流固耦合数值模拟,捕捉引发边坡的初始微小变形和整体宏观渐进性损伤变化,提取降雨前后坡脚敏感部位的应力路径和土颗粒接触力链,从细观角度揭示了降雨诱发土质边坡失稳破坏的触发机制。结果表明:降雨前,坡脚是整个边坡的敏感部位,呈现出应力集中状态。降雨后,雨水入渗并在坡脚处产生最大渗流速度,坡脚处大颗粒间通过骨架作用形成的力链拱形态逐渐被减弱。降雨触发土质边坡失稳破坏的本质在于较大的渗流力不断冲蚀坡脚处土颗粒间原本稳固的接触力链,使其以群体运动的方式发生由外向内渐进性减弱―断裂―消失。坡脚破坏触发后,颗粒间接触力链损伤区域明显大于位移塑性区(或剪切带),靠近坡面的土体应力迅速从高应力转变为低应力,后期因土体颗粒继续滑移滚动,土体应力状态又呈波动性逐渐增加,整个过程中坡脚处应力路径最长。边坡滑移后易在滑移面后边缘形成应力集中的力链拱形态,突显出边坡破坏后具有一定的自稳能力。Rainfall-induced instabilities in highly permeable earthen slopes typically originate at the slope toe;however,the triggering mechanism remains unclear.In this study,we captured the initial microscopic deformations and the overall macroscopic progressive damage of slope instability,extracted the stress paths and contact force chains of soil particles in different parts of the slope before and after rainfall,and revealed the triggering mechanism of soil slope instability induced by rainfall by conducting model tests and utilizing CFD-DEM(computational fluid dynamics-discrete element method)fluid-structure coupling numerical simulations.Our findings revealed that the slope toe exhibits stress concentration prior to rainfall and is a sensitive area of the entire slope before rainfall.After rainfall,rainwater infiltrates,and the seepage rate is the highest near the slope toe.The force-chain arch formed by the large particles at the slope toe,which play the role of the skeleton,is gradually weakened.The essence of rainfall-induced soil slope failure lies in the gradual erosion of the stable contact force chains between soil particles at the slope toe by seepage forces,leading to a progressive weakening,fracture,and disappearance from the outside inward in a collective movement.Once the failure of the slope toe is triggered,the damage area of the inter-granular contact force chains is significantly larger than the displacement plastic zone(or shear band),and the stress in the soil near the slope rapidly transitions from high to low.Subsequently,as the soil particles continue to slip and roll,the soil stress fluctuates and gradually increases,forming a stress-concentrated force chain arch at the rear edge of the slip surface highlighting the slope’s certain self-stabilizing capability after failure.Throughout the process,the stress path at the foot of the slope is the longest.

关 键 词：降雨边坡 触发机制 土质边坡 CFD-DEM流固耦合 细观研究 

分 类 号：TU457[建筑科学—岩土工程]