人工制备土的结构性及其对应变局部化的影响  

Structure of artificial soils and its influence on strain localization

作　　者：凌道盛[1,2] 李奖 王文军[2] 胡成宝 LING Dao-sheng;LI Jiang;WANG Wen-jun;HU Cheng-bao(Institute of Geotechnical Engineering,MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering,Zhejiang University,Hangzhou 310058,China;School of Civil Engineering and Architecture,Ningbo Institute of Technology,Zhejiang University,Ningbo 315100,China)

机构地区：[1]浙江大学岩土工程研究所软弱土与环境土工教育部重点实验室,浙江杭州310058 [2]浙江大学宁波理工学院土木建筑工程学院,浙江宁波315100

出　　处：《浙江大学学报（工学版）》2019年第9期1689-1696,共8页Journal of Zhejiang University：Engineering Science

基　　金：国家重点研发计划资助项目(2016YFC0800200);国家“973”重点基础研究发展规划资助项目(2014CB047000);国家自然科学基金资助项目(51578502).

摘　　要：采用人工制备土方法和固结不排水(CU)剪三轴试验开展研究.通过在宁波滨海粉质黏土中加入少量水泥和盐粒构造多组结构性强弱不同的人工结构性土,固结不排水剪三轴试验结果表明:水泥掺量为2%的试样的结构性与宁波原状粉质黏土最为接近,达到了利用人工制备结构性土来模拟原状土的效果.随着水泥掺量的增加,人工结构性土的有效黏聚力近似呈指数形式增长,有效内摩擦角没有明显变化,初始变形模量增大.在相同围压下,随着土体结构性的增强,试样更易发生应变局部化并出现剪切带破坏;应力-应变曲线出现软化,峰值点应力增大且对应轴向应变呈减小趋势.对于同一种土体,结构性差异对剪切带倾角值影响不大,Mohr-Coulomb理论对剪切带倾角的预估值与实测值较为吻合.The artificial soil preparation method and consolidated undrained(CU)shear triaxial test were used.A series of structural soils with structural differences were constructed by adding a small amount of cement and salt grains to the Ningbo coastal silty clay.The CU test results show that the structure of the sample with 2%cement content is similar to the undisturbed Ningbo silty clay,thus achieving the goal of using artificially structured soil to simulate the undisturbed soil.With the increase of cement content,the effective cohesion of the artificially structured soil increases in an approximate exponential form,and there is no obvious change in the effective internal friction angle,and the initial deformation modulus increases.Under the same confining pressure,with the enhancement of soil structure,the specimens are prone to strain localization and shear band failure;the stress-strain curve is more probably to be strain-softened,and the peak stress increases,while the corresponding axial strain shows a decreasing trend.For the same kind of soil,difference in structures has little effect on the inclination angle of shear band,and the prediction value by Mohr-Coulomb theory agrees well with the measured value of the inclination angle of shear band.

关 键 词：人工制备结构性土 宁波滨海粉质黏土 应变局部化 剪切带倾角 固结不排水剪三轴试验 

分 类 号：TU411[建筑科学—岩土工程]