含水率变化对四川山矾根土摩阻特性和边坡稳定性影响  

Effects of soil moisture content changes on friction characteristics and slope stability of Symplocos setchuensis

作　　者：刘雪璇 郑培龙 梁军 王玉杰[1,2] 李通 王余靖 王鑫皓 王云琦[1,2] LIU Xuexuan;ZHENG Peilong;LIANG Jun;WANG Yujie;LI Tong;WANG Yujing;WANG Xinhao;WANG Yunqi(Three-Gorges Reservoir Area(Chongqing)Forest Ecosystem Research Station,Ministry of Education,School of Soil and Water Conservation,Beijing Forest University,100083,Beijing,China;Three-Gorges Reservoir Area(Chongqing)Forest Ecosystem Research Station,School of Soil and Water Conservation,Beijing Forest University,100083,Beijing,China;Beijing Water Conservation and Ecological Engineering Consulting Co.,Ltd.,100055,Beijing,China;Chongqing Zhonglinfeng Technology Department Co.,Ltd.,400000,Chongqing,China)

机构地区：[1]北京林业大学水土保持学院、重庆三峡库区森林生态系统教育部野外科学观测研究站,北京100083 [2]北京林业大学水土保持学院、重庆缙云山三峡库区森林生态系统国家定位观测研究站,北京100083 [3]北京水保生态工程咨询有限公司,北京100055 [4]重庆市中林峰科技发展有限公司,重庆400000

出　　处：《中国水土保持科学》2025年第1期70-79,共10页Science of Soil and Water Conservation

基　　金：国家重点研发计划“生态保护带人工防护林结构近自然改造与水土保持功能提升技术与示范”(2023YFF1305201)。

摘　　要：含水率是土壤物理性质中变化最频繁的指标,不但影响土体的表观强度,还影响根土力学作用。目前浅层边坡稳定性评估研究中,关于土壤含水率对根系固土能力影响的考虑较少。为明确根土界面特性—土壤含水率的关系,并探讨在边坡稳定分析中考虑该关系的必要性,本研究开展以土壤含水率为变量的根土直剪摩擦试验,并将3种不同模型下根土界面摩阻特性(“本文动态模型”、Wu模型和FBM模型)分别纳入对根系附加强度的估算中,最后采用GEO-Studio软件对边坡稳定性进行模拟。结果表明:1)随着土壤含水率的增加,四川山矾根系抗拉和拔强度均与根径呈负幂函数关系,2条曲线通常具有交点,其对应的根径随着含水率升高先增后减,范围为0.12~2.75 mm;2)随着土壤含水率的增加,实测的根土界面摩擦系数先增后减;3)3种模型估算的根增附加黏聚力c_(r):c_(r)(f)<c_(r)(FBM)<c_(r)(Wu),且含水率越高,c_(r)(f)与c_(r)(FBM)和c_(r)(Wu)的偏差越大;4)将3种模型下根增附加黏聚力c_(r)纳入边坡稳定性评估中,边坡稳定系数均随含水率升高而降低,“本文动态模型”稳定系数的估算值更保守,Wu和FBM模型约为“本文动态模型”的1.53和1.02倍,说明分析植被边坡稳定性时应考虑根土界面摩擦特性随土壤含水率的动态变化。[Background]Moisture content is the most frequently changing indicator of soil physical properties,which not only affects the apparent strength of the soil,but also affects the root-soil mechanical action.In the current shallow slope stability assessment researches,the impact of soil moisture content on the root reinforcement is rarely considered.[Methods]In order to clarify the relationship between the root-soil interfacial characteristics and the soil moisture content,and to study the influence of soil moisture on the friction coefficient of root-soil complex,root shear strength and root failure mode,we carried out Symplocos setchuensis root tensile test,root-soil friction experiment based on nine soil moisture content gradients.Then we estimated the additional cohesion of root(cr)under three models through BSTEM(bank stability and toe erosion model)to contrastively analyze root reinforcement.At last,we used GEO-Studio to evaluate slope stability and to analyze the change of slope stability under different soil moisture contents.[Results]1)The tensile strength and pull-out strength of S.setchuensis roots decreased with the increase of root diameter,and the two curves usually had an intersection point and its corresponding root diameter first increased and then decreased(0.12-2.75 mm).2)The friction coefficient of root-soil interface decreased with the increase of soil moisture content.3)The additional cohesion of roots(cr)both increased with the increase of soil moisture content when considering the frictional characteristics of root-soil interface under different soil moisture content:c_(r)(f)<c_(r)(FBM)<c_(r)(Wu),the deviation of c_(r)(f)to c_(r)(FBM)and c_(r)(f)to c_(r)(Wu).4)The slope factor of safety(Fs)decreased with the increase of soil moisture content,and it was more conservative when considering the characteristics of root-soil interface.Fs(Wu)and Fs(FBM)were about 1.53 and 1.02 times of Fs(f).[Conclusions]Soil moisture content influenced the failure mode and pull-out strength of roots by affecting th

关 键 词：根系固土 根土界面摩阻特性 降雨入渗 土壤含水率 边坡稳定性 

分 类 号：S157[农业科学—土壤学]