非饱和玄武岩残积土强度特性及其边坡稳定性分析  

Study on Strength Characteristics of Unsaturated Basalt Residual Soil and Its Slope Stability

作　　者：李勇[1] 雷学文[1] 孟庆山[2] 陈洁[1,3] 张浪[1] 

机构地区：[1]武汉科技大学城市建设学院,湖北武汉430065 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [3]仲恺农业工程学院城市建设学院,广东广州510225

出　　处：《公路交通科技》2017年第5期50-56,共7页Journal of Highway and Transportation Research and Development

基　　金：交通运输部西部交通建设科技项目(2009318802074)

摘　　要：为探究非饱和土抗剪强度及其指标随含水率的变化规律,以毕威高速公路沿线某边坡黄褐色玄武岩残积土为研究对象,进行了控制含水率的直剪试验和土水特征曲线测试试验,通过Abaqus建立以此边坡为原型的有限元模型,在此基础上运用强度折减法对不同含水率的边坡进行稳定性分析,并结合试验所得的土水特征曲线分析基质吸力对边坡稳定性的影响。结果表明:随含水率增大,抗剪强度先基本不变后大幅度减小,黏聚力与内摩擦角均呈阶段性减小;基质吸力对抗剪强度的贡献随基质吸力的增大而逐渐减小并最终趋近于无影响;含水率对玄武岩残积土质边坡稳定性有较大的影响,边坡土体的含水率大于30%后,随含水率增加,边坡安全系数大幅度降低;含水率增大会降低土体的基质吸力,在边坡土体接近饱和时,基质吸力的丧失对边坡稳定性影响最大,此时边坡最易失稳滑塌。In order to explore the rule of shear strength and its indexes varying with water content of unsaturated soil, the direct shear test of controlled water content and the test of soil-water characteristic curve on the brown basalt residual soil from a selected slope of Bijie-Weining expressway are conducted. Based on the finite element model of the slope established by Abaqus, the slope stability with different water contents are analysed by shear strength reduction method, and the effect of matric suction on slope stability is analyzed with the soil-water characteristic curve obtained from the experiment. The result shows that （ 1 ） with the increase of water content, the shear strength basically remains at first and then decreases significantly the cohesion and internal friction angle present a trend of decrease in stage; （2） the contribution of matrix suction to shear strength gradually decreases and eventually tends to zero with the increase of matrix suction; （3） water content has a great influence on the stability of the basalt residual soil slope, and the safety factor of the slope is greatly reduced with the increase of the water content when the water content of the slope is more than 30% ; （4） the increase of water content will decrease the matrix suction of soil mass, and the loss of matrix suction has the biggest influence on the slope stability when the slope soil is close to saturation, at this time the slope is the most vulnerable.

关 键 词：道路工程 玄武岩残积土 直剪试验 抗剪强度 边坡稳定性 基质吸力 

分 类 号：U412.22[交通运输工程—道路与铁道工程]