浙东大运河非饱和粉质黏土抗剪强度特性的试验研究  

Experimental Study on Shear Strength Characteristics of Unsaturated Silty Clay in East Zhejiang Grand Canal

作　　者：汤有志 吴瑞潜 杨光 TANG Youzhi;WU Ruiqian;YANG Guang(College of Civil Engineering,Shaoxing University,Shaoxing 312000,Zhejiang,China;Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing 312000,Zhejiang,China;Zhejiang Collaborative Innovation Center for Prevention and Control of Mountain Geologic Hazards,Shaoxing 312000,Zhejiang,China)

机构地区：[1]绍兴文理学院土木工程学院,浙江绍兴312000 [2]浙江省岩石力学与地质灾害重点实验室,浙江绍兴312000 [3]浙江省山体地质灾害防治协同创新中心,浙江绍兴312000

出　　处：《力学季刊》2021年第2期360-369,共10页Chinese Quarterly of Mechanics

基　　金：国家青年基金(51708354)。

摘　　要：浙东大运河绍兴段的土体整体上受河流相和海相沉积的影响,地质条件非常复杂.其中粉质黏土作为浅表层土体,受雨水影响较大,其状态经常处于饱和状态与非饱和状态之间.为了进一步探究绍兴段典型非饱和粉质黏土的稳定性差异,以及本构关系和强度指标的变化规律,通过全自动非饱和土应力路径三轴仪,对试验土样进行了三轴剪切试验.试验结果表明,初始干密度从1.4 g/cm3增加到1.6 g/cm3时,土体的抗剪强度、总黏聚力、有效内摩擦角和吸附内摩擦角均增大,应力-应变关系曲线由应变硬化型向应变软化型转变,并且基质吸力和净围压越大,区别越明显;基质吸力从0增加到300 kPa时,土体的抵抗变形能力提高,抗剪强度和总黏聚力增大,有效内摩擦角基本无明显变化,吸附内摩擦角逐渐减小.研究结果揭示了浙东大运河绍兴段非饱和粉质黏土的抗剪强度特性的变化规律,为该地域土质边坡、基坑等工程提供理论依据.The soil in Shaoxing section of the Eastern Zhejiang Grand Canal is generally affected by the fluvial and Marine sediments,leading to the complex geological conditions.Silty clay,as the shallow surface soil,is greatly affected by the rainfall,and its state is often between saturated and unsaturated.In order to further explore the stability difference of typical unsaturated silty clay in Shaoxing section,as well as the variation of the constitutive relationship and the strength index,the consolidation drainage triaxial shear tests are carried out on the soil samples by the triaxial apparatus of fully automatic stress path.The results show that as the initial dry density increases from 1.4 g/cm3 to 1.6 g/cm3,the shear strength,the total cohesion,the effective internal friction angle and the adsorptive internal friction angle of the soil increase,the stress-strain relationship curve changes from strain hardening to strain softening.The tendency is more obvious with the increase of matric suction and net confining pressure.As the matric suction increases from 0 kPa to 300 kPa,the resistance to deformation,the shear strength and the total cohesion of soil increase,while the effective internal friction angle does not change obviously,and the adsorption internal friction angle decreases gradually.The results reveal the characteristics of the shear strength of the unsaturated silted clay in Shaoxing section of the Eastern Zhejiang Grand Canal,which provide a theoretical basis for soil slope and foundation pit engineering in this region.

关 键 词：非饱和土 抗剪强度 初始干密度 基质吸力 应力-应变关系 

分 类 号：TU447[建筑科学—岩土工程] TU43[建筑科学—土工工程]