广西容县花岗岩残积土人工切坡诱发滑坡过程分析  

Granite Residual Soil Landslide Induced by Artificial Cutting Slope in Rong County,Guangxi Province,China

作　　者：韦文智 赵瑞华 廖丽萍[1,2,3] 刘政委 WEI Wenzhi;ZHAO Ruihua;LIAO Liping;LIU Zhengwei(College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education, Guangxi University, Nanning 530004, China;Guangxi Key Laboratory of Disaster Prevention and Engineering Safety, Guangxi University, Nanning 530004, China)

机构地区：[1]广西大学土木建筑工程学院,南宁530004 [2]工程防灾与结构安全教育部重点实验室,南宁530004 [3]广西防灾减灾与工程安全重点实验室,南宁530004

出　　处：《山地学报》2022年第3期396-410,共15页Mountain Research

基　　金：国家自然科学基金项目(41901132);广西科技厅基金(2018GXNSFAA138187)。

摘　　要：广西容县花岗岩残积土属于中国华南地区特殊土,人工切坡频繁失稳诱发大量滑坡,严重威胁当地居民生命财产安全。过去研究多数聚焦于岩质或黄土切坡失稳问题,未考虑降雨激发下特殊土切坡引发滑坡的动力学过程。本文以花岗岩残积土人工切坡为研究对象,采用数值模拟和人工降雨土槽模型试验,定量揭示切坡坡度和切坡高度对无裂隙边坡稳定性的影响规律,对比分析自然、无裂隙、含裂隙边坡的稳定性,探讨切坡诱发滑坡的动力学过程。结果表明:(1)当切坡坡度由50°增至70°或切坡高度由2 m增至14 m,切坡无裂隙边坡稳定性系数的减小幅值约为0.2;观测点a与c的孔隙水压力的响应时间分别提前3 h与11 h,4 h与16 h。(2)当切坡坡度为60°和高度为8 m时,降雨前后自然边坡、切坡无裂隙边坡的稳定性系数分别由1.30、1.21缓慢地下降至1.26、1.17,而切坡含裂隙边坡的稳定性系数却由1.21急剧下降至0.98,切坡与裂隙对边坡稳定性的耦合负面影响不容忽视。(3)坡脚的体积含水率响应时间最短;体积含水率的响应时间较孔隙水压力的早;孔隙水压力的增减波动与其消散的时间尺度、降雨入渗、土体剪切变形有关。(4)花岗岩残积土切坡诱发滑坡的动力学过程为卸荷裂隙形成→坡脚失稳→表面侵蚀与沟道侵蚀→张拉裂隙形成与局部土体滑动。研究成果将为花岗岩残积土工程边坡的防护治理提供理论依据。The granite residual soil developed in Rong county,Guangxi province is the special soil in south China.Massive landslides occurring in the slopes of granite residual soils due to engineering excavations are posing great threats to the safety of life and property of local community.Most of the past efforts focused on the instability of rock or loess slopes.The dynamic process of landslide induced by special soil excavation under rainfall excitation has not been studied.In this paper,granite residual soils and associated cutting slopes were targeted for investigation.Numerical simulation was conducted to quantitatively observe the effects of the cutting angle and height on the stability of soil slopes,which were initially remolded into a unity with no cracks inside or on the surface.Then,it followed by the comparative study,in which natural slope,non-cracked slope and cracked slope was included as control condition separately.Finally,the dynamic process of landslide induced by cutting slope was discussed by employing the artificial flume model test.The following results are obtained:(1)As the cutting angle was increased from 50°to 70°or the cutting height was increased from 2 m to 14 m,the stability factor of the non-cracked cutting slope decreased by 0.2.The response time of pore water pressure at the observation point(a,c)was advanced by 3 h and 11 h,4 h and 16 h,respectively.(2)Prior to artificial rainfall,the stability coefficient of natural slope and non-cracked cutting slope at cutting angle 60°with height 8 m was 1.30 and 1.21 separately;then they decreased to 1.26 and 1.17 slowly after rainfall,whereas the stability factor of cracked cutting slope dropped from 1.21 to 0.98 in a sharp manner.The coupled negative effect of slope cutting and cracks on stability could not be ignored.(3)The volume moisture content had the most direct response at the slope foot.The response time of water content was earlier than that of pore water pressure.Fluctuations in pore water pressure were related to its dissipation tim

关 键 词：花岗岩残积土 人工切坡 滑坡形成过程 广西 容县 

分 类 号：P642[天文地球—工程地质学]