崩岗区岩土抗剪强度主要影响因素及衰减机理分析  

Analysis of Decay Mechanism and Influence Factors of Soil Anti-shear Strength in Slope Disintegration Erosion Area

作　　者：张晓明[1] 丁树文[1] 蔡崇法[1] 林辉[1] 

机构地区：[1]华中农业大学资源与环境学院,湖北武汉430070

出　　处：《安徽农业科学》2012年第9期5534-5537,5581,共5页Journal of Anhui Agricultural Sciences

基　　金：中央高校基本科研业务费专项(2009QC035);华中农业大学科研启动资金项目(52204-08077);"十二五"国家科技支撑计划项目(2011BAD31B00)

摘　　要：根据崩岗侵蚀区红土发育于花岗岩且受干湿变化影响显著的性质,通过室内直剪试验,分析了5种干湿效应水平(风干48 h、风干24 h、自然含水率、浸水30 s和浸水60 s)崩岗侵蚀区岩土抗剪强度变化规律,并运用灰色关联法研究了影响岩土抗剪强度指标的主要因素。结果表明,土壤黏聚力c和内摩擦角φ随干湿变化呈非线性衰减趋势;在风干阶段影响抗剪强度前3个主要因素大小依次为塑性指数>游离氧化铁>黏粒含量,主要受裂隙性影响,而在增湿阶段影响程度大小依次为干密度>水溶性盐>黏粒含量,基质吸力是控制抗剪强度衰减的主要因素。Abstract According to the properties of red soil derived from granite in slope disintegration area and influenced significantly by wetting and drying, the variation law of anti-shear strength was analyzed under five soil wetting and drying treatments （ drying 48 h, drying 24 h, natural water content, wetting 30 s, wetting 60 s） by direct shearing test. The main influencing factors of soil anti-shear strength index were studied by using gray relational method. The results showed that soil cohesive forceand internal frictional angle Ф decline with variation of drying and wetting levels ; anti-shear strength is dominantly affected by crack evolution during drying period, the order of the effects of the influence factors on cohesion is plasticity index 〉 free iron oxide 〉 clay content, while matrix suction is the main factor for anti-shear strength decline during wetting period, the order of the effects of the influence factors on cohesion is dry density 〉 water soluble salt 〉 clay content.

关 键 词：抗剪强度 黏聚力 灰色关联法 内摩擦角 

分 类 号：S157[农业科学—土壤学]