膨胀土强度的室内直剪和原位推剪对比试验研究  

Eexperimental study of direct shear and in situ clipper on strength of expansive soil

作　　者：杨果林[1] 滕珂[1] 谢兰芳 

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]广东省航运规划设计院有限公司,广东广州510050

出　　处：《中南大学学报（自然科学版）》2014年第6期1952-1959,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51278499);铁道部科技研究开发计划项目(2010G016-B)

摘　　要：针对广西百色地区膨胀土扰动土与原状土差距大的特点,采用室内试验和原位试验相结合的方法,通过直剪试验和原位推剪试验研究土体不同饱和度及不同密实度对强度的影响和变化规律。通过直剪试验拟合的公式结合原位试验结果,推算饱和状态下原状土的强度指标,为膨胀土边坡稳定验算提供较可靠的参数。研究结果表明:饱和度对强度的影响较大,密度对强度的影响较小,黏聚力和内摩擦角与饱和度的对数均有很好的线性相关性,黏聚力受饱和度的影响比内摩擦角受饱和度的影响明显;原状土抗剪强度大于扰动土抗剪强度,当饱和度增大时,原状土黏聚力衰减速率比扰动土的大;原状土内摩擦角衰减速率比扰动土的小。Aiming at the big gap between the characteristics of disturbed soil and undisturbed soil of Baise expansive soil,direct shear tests and in situ clipper tests were carried out to study the change of the soil strength and the influence of the change rule caused by different saturations and compactnesses. Through the direct shear test fitting formula combined with the in-situ test results,the strength of the undisturbed soil saturated condition index was calculated to provide reliable parameters of expansive soil slope stability calculation. The results show that saturation has bigger influence on the strength and density has less effect on the strength, cohesive force and angle of internal friction and the logarithm of saturation have good linear correlation. The influence of saturation on cohesive force is bigger than the internal friction angle. Undisturbed soil shear strength is greater than that of the disturbed soil. When the saturation increases, the cohesive force attenuation rate of the undisturbed soil is greater than that of the disturbed soil,while the undisturbed soil angle of internal friction attenuation rate is smaller than that of the disturbed soil.

关 键 词：膨胀土 强度 饱和度 密实度 直剪 原位推剪 

分 类 号：TU413.1[建筑科学—岩土工程]