循环加载方向角对饱和粉土不排水动力特性的影响  

Effect of the direction angle of cyclic loading on undrained cyclic behavior of saturated silt

作　　者：周正龙[1] 陈国兴[1] 赵凯[1] 吴琪[1] 马维嘉 

机构地区：[1]南京工业大学岩土工程研究所,江苏南京210009

出　　处：《岩土力学》2018年第1期36-44,共9页Rock and Soil Mechanics

基　　金：国家科技重大专项(No.2014CB047005);国家自然科学基金项目(No.41172258;No.51438004)~~

摘　　要：利用GDS空心圆柱仪进行了一系列主应力方向角?d变化的轴向、扭转、内压和外压四向耦合不排水循环剪切试验。在均等固结条件下,着重研究了循环加载方向角?d0对饱和粉土动力特性的影响。试验结果表明:饱和粉土的双规准化孔压发展模式与?d0无关,但受循环应力比CSR的影响;广义剪应变的发展模式不受?d0的影响。在循环剪切过程中,循环加载方向的变化对粉土的不排水动强度有显著影响,饱和粉土的动强度CRR随着?d0的增大呈现出先减小后增大的变化趋势,且当?d0=45°时CRR最小。同时,建立了反映?d0与CSR影响的孔压、变形的模型,并给出了相应的动强度表达式。This study investigated the impact of the direction of cyclic loading on the cyclic behavior of saturated silt under isotropic consolidation condition. GDS hollow cylinder torsional apparatus was employed to perform a series of undrained cyclic shear tests with various principal stress direction angle ad0 coupling with four dynamic loads, i.e., inner pressure, outer pressure, axial load and torque. The results show that the double normalized pore pressure is independent on the direction angle of cyclic loading, but sensitive to the cyclic stress ratio CSR. The generalized shear strain is independent on the direction angle of cyclic loading during cyclic loading. The direction angle of cyclic loading during cyclic shearing has a considerable influence on undrained cyclic resistance ratio of saturated silt. Cyclic resistance ratio CRR initially decreases then increases as the direction angle of cyclic loading increase, with a minimum value for od0=45°. Meanwhile, equations for pore water pressure and deformation to quantify the influence of od0 and CSR are established and the corresponding expression for CRR is given.

关 键 词：粉土液化 循环加载方向角 循环应力比 孔隙水压力 广义剪应变 动强度 

分 类 号：TU411[建筑科学—岩土工程]