强降雨作用下引入分形理论的浅层边坡入渗及稳定性分析  

Analysis of infiltration and stability of shallow slopes under heavy rainfall conditions with fractal theory corrections

作　　者：张小东 路喆津 刘敏 杨峰[1] 赵炼恒[1,3] ZHANG Xiaodong;LU Zhejin;LIU Min;YANG Feng;ZHAO Lianheng(School of Civil Engineering,Central South University,Changsha 410000,China;Shenzhen General Integrated Transportation and Municipal Engineering Design&Research Institute Co.,Ltd.,Shenzhen 518003,Guangdong,China;Key Laboratory of Heavy-Haul Railway Engineering Structure of Ministry of Education(Central South University),Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,长沙410000 [2]深圳市综合交通与市政工程设计研究总院有限公司,广东深圳518003 [3]重载铁路工程结构教育部重点实验室(中南大学),长沙410075

出　　处：《哈尔滨工业大学学报》2024年第11期140-150,共11页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(51978666);湖南省杰出青年基金(2021JJ10063)。

摘　　要：为探究降雨过程中土体实际入渗能力动态变化对边坡降雨入渗规律及其稳定性的影响,从土体级配特征的角度出发,首先基于分形理论推导了不同级配特征土体的饱和渗透系数分析模型;进一步考虑入渗区椭圆形过渡带的影响,根据不同降雨历时下过渡带与入渗区的厚度比例关系对入渗区等效渗透系数进行实时修正,提出了不同级配特征土体的改进GA入渗模型;最后,基于改进GA入渗模型建立了考虑土体抗剪强度随级配特征及降雨时间变化的浅层边坡稳定性分析修正模型。与已有结果对比表明建立的模型能够准确地表征降雨过程中土体入渗状态及剪切强度变化特征。参数分析表明:土体孔隙分布特征与饱和渗透系数具有明显的正相关关系,其直接影响坡体水分剖面分布及坡面径流出现时间;湿润峰推移速率随坡体初始含水率的增大而加快,致使相同降雨历时下入渗区过渡带占比减小,进而实时影响入渗区等效渗透系数;坡体过渡带稳定性受土体级配特征及初始含水率的影响较为显著,坡体容易在过渡带发生失稳破坏。故在强降雨作用下边坡的失稳分析中,需额外注意入渗区过渡带的稳定性。In order to explore the impact of the dynamic changes in the actual infiltration capacity of the soil during rainfall on the rainfall infiltration patterns and stability of slopes.From the perspective of soil gradation characteristics,this paper first derives an analytical model for the saturated permeability coefficient of soils with different gradation characteristics based on fractal theory.Further considering the influence of the elliptical transition zone in the infiltration area,the equivalent permeability coefficient of the infiltration area is corrected in real-time based on the thickness ratio between the transition zone and the infiltration area under different rainfall durations.An improved GA infiltration model for soils with varying gradation characteristics is proposed.Finally,based on the improved GA infiltration model,a modified shallow slope stability analysis model is established,which takes into account the variation of soil shear strength with gradation characteristics and rainfall duration.Comparison with existing results shows that the model presented in this paper can accurately characterize the infiltration state of the soil and the changes in shear strength during rainfall.Parameter analysis indicates that the pore distribution characteristics of the soil are significantly positively correlated with the saturated permeability coefficient,which directly affects the moisture profile distribution within the slope and the timing of surface runoff occurrence.The migration rate of the wetting front increases with the initial moisture content of the slope,leading to a reduced proportion of the transition zone in the infiltration area under the same rainfall duration,which in turn dynamically affects the equivalent permeability coefficient of the infiltration area.The stability of the slope′s transition zone is significantly influenced by soil gradation characteristics and initial moisture content,making the slope prone to instability and failure within the transition zone.Therefore,in slope in

关 键 词：非饱和土 降雨入渗规律 分形理论 渗透系数 初始含水率 

分 类 号：TU42[建筑科学—岩土工程]