基于足尺模型试验的边坡裂隙发展演化规律  

Evolution law of cracks based on full-scale model test of slope

作　　者：张家铭[1] 罗易 周峙[1] CHIKHOTKIN Victor 袁超 王少锋 ZHANG Jiaming;LUO Yi;ZHOU Zhi;CHIKHOTKIN Victor;YUAN Chao;WANG Shaofeng(Faculty of Engineering,China University of Geosciences,Wuhan 430074,China;Anhui Transportation Holding Group Co.,Ltd.,Hefei 230088,China)

机构地区：[1]中国地质大学工程学院,湖北武汉430074 [2]安徽省交通控股集团有限公司,安徽合肥230088

出　　处：《中南大学学报（自然科学版）》2020年第4期1037-1048,共12页Journal of Central South University:Science and Technology

基　　金：安徽省2018年度交通运输科技进步计划项目(2018030);中央高校基本科研业务费专项资金资助项目。

摘　　要：以安徽沿江地区裂土为研究对象,开展降雨-蒸发作用下裂土边坡足尺模型试验,测量土体表层含水率、基质吸力及裂隙深度,采用图像矢量化技术提取边坡不同部位裂隙几何参数,研究平面及深度方向裂隙发展演化特征,划分裂隙类型,揭示边坡裂隙发展演化机理。研究结果表明:裂隙的发展演化受其所处位置和降雨-蒸发次数控制。坡顶中后缘部位受边坡临空面影响较小,裂隙均为干缩裂隙,属I型张开断裂;坡肩及坡顶前缘受临空面影响较大,裂隙为干缩-剪切复合裂隙,属I-Ⅱ复合型断裂;平面上,干缩裂隙的裂隙率与含水率呈高度线性负相关,干缩-剪切复合裂隙率与含水率线性关系较差;随降雨-蒸发次数增加,裂隙的平均宽度逐次增加,裂隙总长度表现为前期波动变化,后期趋于稳定,其中坡肩附近复合裂隙的裂隙率和平均宽度最大,其裂隙总长度小于坡顶干缩裂隙总长度;干缩裂隙在平面上呈网状结构,干缩-剪切复合裂隙平面上出现显著定向特征;深度方向上,裂隙导致相应深度基质吸力在降雨时剧烈下降、在干燥时剧烈上升;干缩裂隙竖直发展,干缩-剪切复合裂隙出现转向现象;总体上,坡肩处裂隙最发育,坡顶次之,坡脚最弱,坡体的破坏始于坡肩处的干缩-剪切复合裂隙。The cracked soil in the area along the Yangtze River in Anhui Province was researched to reveal the evolution mechanism of cracks in the slope.Through the full-scale model test of cracked soil cutting slope during rainfall-evaporation,the surface moisture content,matrix suction and crack depth of soil were measured,and image vectorization technique was employed to obtain the crack parameters in different positions of the slope.Evolution law of cracks in the plane and depth direction and fracture modes of cracks were discussed to reveal the evolution pattern of cracks in the slope.The results show that the evolution law of cracks is significantly influenced by the positions at the slope and rainfall-evaporation cycles.The cracks on the middle-back edge of the slope crest are desiccation cracks and belong to mode I open fracture in the whole test because they are rarely affected by the free face.Conversely,cracks at the slope shoulder and the front edge of the slope crest are desiccate-shear cracks and belong to I-II composite fracture because they are greatly influenced by the free face.In the plane direction,crack rate of the desiccation cracks is highly linear and negatively correlated with the moisture content,but the linear relationship between the crack rate and moisture content of the composite cracks is poor.The influence of rainfall-evaporation on the different plane parameters of cracks are also different from each other.With the increase of rainfall-evaporation cycles,the average width of different cracks gradually increases,and their total length fluctuates at the early stages and tends to be stable at the later stages.Desiccation cracks exhibit a polygonal plane pattern instead of an oriented structure such as desiccate-shear cracks at the slope shoulder.In the depth direction,the matric suction in the corresponding depth descends during the rainfall and increases steeply during the drying due to the cracks.Desiccation cracks extend a near vertical direction rather than a new direction.In conclusion,th

关 键 词：裂土边坡 裂隙 降雨-蒸发 足尺模型 演化规律 

分 类 号：TU44[建筑科学—岩土工程]