膨胀土边坡稳定性研究  

Study on the Stability of Expansive Soil Slope

作　　者：程展林[1,2] 李青云[3] 郭熙灵[1] 龚壁卫[2] 

机构地区：[1]长江科学院院长办公室,武汉430010 [2]长江科学院水利部岩土力学与工程重点实验室,武汉430010 [3]长江科学院流域水环境研究所,武汉430010

出　　处：《长江科学院院报》2011年第10期102-111,共10页Journal of Changjiang River Scientific Research Institute

基　　金：国家"十一五"科技支撑计划项目(2006BAB04A10)

摘　　要：阐述了近年来长江科学院在膨胀土边坡稳定性方面的研究成果。研究了南水北调中线工程膨胀土的裂隙形态及分布规律,在"大气影响深度"以上与以下区域膨胀土的裂隙形态存在差异,以下区域的裂隙具有明显的定向性;介绍了膨胀土的膨胀性,对于起始含水率一定的膨胀土,相同吸湿条件下的膨胀应变与平均应力在半对数坐标系下呈很好的线性关系;阐述了膨胀土的强度特性,提出了膨胀土强度试验新方法;研究分析了膨胀土边坡失稳机理,提出了膨胀土边坡的破坏模式及相应的稳定分析方法。研究成果表明:膨胀土边坡不仅存在重力作用下的整体稳定性,整体稳定性受裂隙面强度控制,而且在吸湿条件下会产生浅层失稳,浅层失稳的主要影响因素为土的膨胀变形;在膨胀土边坡的稳定分析中,膨胀土的强度,不需进行任何折减,直接采用强度试验值,稳定分析成果能正确地反映边坡的稳定状态。This paper presents some recent advances in the stability analysis of expansive soil slopes by the Changjiang/Yangtze River Scientific Research Institute.Types and distributions of fractures were investigated through researches on the expansive soils in the middle route of the South-to-North Water Diversion Project.It was revealed that differences existed between the fractures of expansive soils of the upper and the lower portions of ＂the depth of atmosphere influence＂.The initial fractures in the lower portion were found to be obviously directional.By dilatancy analysis for the expansive soils with the same initial water content and water absorption,high linear relationship was obtained between the swelling strain and the mean stress in the semi-logarithmic coordinate.The determination of strength and new test method of expansive soils were provided considering heterogeneous anisotropic and nonlinear properties of the strength of expansive soils.The failure mechanism of expansion soils slopes was analyzed,and the deformation modes were also given.The overall stability of expansive soil slopes not only depended on gravity,but was also controlled by the strength of fracture planes;while the destabilization of the shallow soil body was mainly subject to the expansive deformation under moistening.Stability analysis methods were employed for expansion soli slopes with two deformation modes,and the results indicated that the slope stability could be precisely reflected by stability analysis achievements using strength test values.

关 键 词：南水北调 膨胀土 边坡 稳定性 裂隙 CT技术 破坏模式 计算方法 

分 类 号：TU443[建筑科学—岩土工程]