球状风化花岗岩类土质边坡土-岩界面优势流潜蚀特性研究  

Characteristics of preferential flow suffosion of soil-rock interface in spherical weathered granite slopes

作　　者：豆红强[1,2,3] 谢森华 简文彬 王浩[1,2,3] 郭朝旭 DOU Hong-qiang;XIE Sen-hua;JIAN Wen-bin;WANG Hao;GUO Chao-xu(Zijin School of Geoloy and Mining,Fuzhou University,Fuzhou,Fujian 350108,China;Fujian Key Laboratory of Geohazard Prevention,Geological Engineering Survey in Fujian Province,Fuzhou,Fujian 350002,China;Key Laboratory of Geohazard Prevention of Hilly Mountains,Ministry of Natural Resources,Geological Engineering Survey in Fujian Province,Fuzhou,Fujian 350002,China)

机构地区：[1]福州大学紫金地质与矿业学院,福建福州350108 [2]福建省地质工程勘察院福建省地质灾害重点实验室,福建福州350002 [3]福建省地质工程勘察院自然资源部丘陵山地地质灾害防治重点实验室,福建福州350002

出　　处：《岩土力学》2024年第4期950-960,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42007235,No.U2005205);福建省自然科学基金(No.2023J01423);自然资源部丘陵山地地质灾害防治重点实验室开放基金(No.FJKLGH2023K006)。

摘　　要：受降雨作用,球状风化花岗岩类土质边坡的土-岩差异风化界面极易演化为优势渗流通道而发生渗流潜蚀,进而加速该类边坡的变形失稳,然而当前有关其渗流潜蚀作用特征、细颗粒迁移规律等的研究仍鲜见开展。基于多孔介质非饱和渗流理论,综合考虑细颗粒运移、潜蚀启动响应与非饱和渗流的耦合关系,提出一种可准确描述土-岩界面渗流潜蚀过程的数值计算框架。采用有限元方法,构建优势流作用下非饱和花岗岩残积土的渗流潜蚀模型,并以均质土柱的渗流潜蚀过程为参考,系统研究3种典型土-岩界面埋藏状态下的优势流潜蚀特性。结果表明:球状风化花岗岩类土质边坡的土-岩界面与基质渗透性存在高度差异性,湿润锋形成向下凹陷的渗透漏斗,且随着降雨的持续,湿润锋的凹陷程度愈发明显;细颗粒流失程度与土-岩界面的埋藏状态相关,其中下填土体工况的优势流潜蚀最为显著,其界面处甚至出现超孔隙水压力,最不利于该类边坡的稳定性。研究成果可为降雨条件下球状风化花岗岩类土质边坡稳定性的准确评价提供科学依据。Due to rainfall,the soil-rock differential weathering interface of spherical weathered granite soil slopes is prone to evolve into a dominant seepage channel and undergo seepage suffosion,which accelerates the deformation and instability of these slopes.However,little research has been carried out on the characteristics of seepage suffosion and the migration of fine particles.Based on the unsaturated seepage theory of porous media,a numerical calculation framework is established to accurately describe the seepage suffosion process at the soil-rock interface,considering the coupling relationship between the fine particle migration,suffosion initiation response and unsaturated seepage.The finite element method is used to construct a seepage suffosion model for unsaturated granite residual soil under the effect of dominant flow.Based on the seepage suffosion process of homogeneous soil columns,the suffosion characteristics of dominant flow under three typical soil-rock interface burial states are systematically investigated.The results show that the soil-rock interface and the matrix permeability of spherical weathered granite soil slopes are highly variable,with the wetting front forming a downward depression infiltration funnel,and the degree of depression of the wetting front becomes more pronounced as rainfall continues.The degree of fine particle loss is related to the burial state of the soil-rock interface,in which the dominant flow potential suffosion of the under-filled soil condition is the most significant,and even excess pore water pressure occurs at the interface,which is the most unfavorable to the stability of this type of slope.The research results can provide a scientific basis for accurately evaluating the stability of spherical weathered granite soil slopes under rainfall conditions.

关 键 词：优势流潜蚀 有限元 土-岩界面 细颗粒运移 多场耦合 

分 类 号：TU457[建筑科学—岩土工程]