赣东小型土质滑坡形成机理及降雨因子稳定性评价  

Failure mechanism of small-scale soil landslide and quantitative evaluation of rain-induced disaster factors in eastern Jiangxi

作　　者：刘清 甘建军[1] 陈浩 李小明 周国彬 LIU Qing;GAN Jianjun;CHEN Hao;LI Xiaoming;ZHOU Guobin(School of Hydraulic Engineering,Nanchang Institute of Technology,Nanchang 330096,China;Hydrogeological Brigade of Jiangxi Geological Bureau,Nanchang 330096,China)

机构地区：[1]南昌工程学院水利工程学院,南昌330096 [2]江西省地质局水文地质大队,南昌330096

出　　处：《地质科技通报》2024年第6期235-243,共9页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42162025);2022年度江西省自然资源厅科技创新项目(ZRKJ20222310);2021年度浙江省山体地质灾害防治协同创新中心开放基金项目(2PCMGH-2021-02);河北省高校生态环境地质应用技术研发中心开放基金项目(JSYF-Z202201)。

摘　　要：为了研究赣东地区典型土质滑坡成因以及对研究区内降雨因子进行稳定性评价。以江西上饶广丰区紫坞滑坡为例,通过对日降雨量及地表监测位移等数据综合分析并结合GeoStudio有限元软件建立了2D力学模型,模拟了不同降雨条件下小型残坡积土质滑坡的变形情况;分析当地降雨特征,设置了五大工况下4种典型的降雨雨型对比实验,采用多元线性回归进行数据拟合,建立了一种I-D-Fs概化评价模型。研究结果表明:(1)土压力与土壤含水率峰值分别为16.8 kPa和16.3%,降雨初期滑坡土压力与含水率的增加滞后降雨3~5 d;(2)降雨是滑坡发生的主要诱因,该滑坡发生过程可总结为前缘坡体蠕动-后缘滑体拉裂-坡体整体突滑3个阶段;(3)降雨雨型对滑坡稳定性也起着至关重要作用,监测预警应分季进行。当日降雨量较小时,均匀型降雨为其最不利影响型,较其他雨型,稳定性系数最大程度下降2%;当日降雨量较大时,前锋型降雨为其最不利影响型,较其他雨型,稳定性系数最大程度下降8%。研究结果可为浅层土质滑坡灾害的监测预警提供科学参考。[Objective]This study aims to investigate the causes of typical soil landslides in eastern Jiangxi and as-sess the influence of rainfall on slope stability in the region.[Methods]Using the Ziwu landslide in Guangfeng District,Shangrao City,Jiangxi Province as a case study,this paper conducted a comprehensive analysis of rainfall data and surface displacement monitoring.A two-dimensional(2D)mechanical model was established using GeoS-tudio finite element software to simulate the deformation of small residual slope soil landslides under different rain-fall conditions.This study analyzes the local rainfall characteristics,modeled four typical rainfall patterns across five scenarios,applied multiple linear regression to fit the data,and developed an I-D-Fs evaluation model.[Re-sults]The results show that(1)the peak values of earth pressure and soil moisture content are 16.8 kPa and 16.3%,respectively,with a 3 to 5 days lag between rainfall onset and the increase in these values during the early sta-ges of rainfall;(2)rainfall is the primary trigger for landslides,which progress through three distinct phases:Creeping of the front slope,pulling of the rear slope,and sudden sliding of the whole slope;and(3)rainfall pat-terns significantly impact slope stability,necessitating seasonal monitoring and early warning systems.During peri-ods of low rainfall,uniform rainfall is the most detrimental,decreasing the stability coefficients by 2%compared to other patterns.During heave rainfall,frontal rainfall is the most hazardous,decreasing the stability coefficient by 8%compared to other patterns.[Conclusion]These results provide a scientific basis for the monitoring and early warning of shallow soil landslides.

关 键 词：土质滑坡 数值模拟 变形机理 多元线性回归 I-D-Fs模型 赣东地区 降雨因子 

分 类 号：P642.22[天文地球—工程地质学]