不同初始固结应力条件下主应力方向对海洋密砂不排水单调剪切特性的影响  

Effect of Principal Stress Direction on Undrained Monotonic Shear Behaviour of Marine Dense Sand Under Different Initial Consolidation Stress

作　　者：张磊[1,2] 王忠涛[1,2] 刘鹏[1,2] 栾茂田[1,2] 申宏[3] 

机构地区：[1]大连理工大学土木工程学院岩土工程研究所,辽宁大连116024 [2]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024 [3]国家海洋局第一海洋研究所,山东青岛266061

出　　处：《海岸工程》2013年第2期1-10,共10页Coastal Engineering

基　　金：国家自然科学基金青年科学基金项目--波浪作用下海床液化机理及分析方法研究(50909014);国家自然科学基金项目--海上风机桩基础稳定性分析与离心模型试验验证研究(51079018);国家重大科技专项--南海深水油气开发示范工程子课题"南海北部陆坡区地质灾害风险评价预测研究"(2011ZX05056-001-02)

摘　　要：利用大连理工大学的"土工静力-动力液压-三轴扭转多功能剪切仪",针对相对密实度为70%的福建标准砂,在不排水条件下控制试验过程中的中主应力系数保持不变,进行了不同初始固结应力条件下不同主应力方向的单调剪切试验。以此着重探讨了主应力方向及初始固结应力对饱和密砂单调剪切特性的影响,研究表明,主应力方向和初始固结应力对于密砂的有效应力路径和应力-应变关系均具有十分显著的影响。通过与饱和松砂不排水单调剪切特性的对比分析,探讨了初始相对密实度对砂土剪切特性的影响,研究表明随着主应力方向角增大,密砂的应变硬化效应逐渐减弱,但未出现松砂对应的应变软化现象。In order to investigate the effect of principal stress direction and initial consoli- dation stress on undrained monotonic shear behavior, monotonic shear tests under different principal stress directions and different initial consolidation stresses were conducted by using the Fujian standard sand with a relative density of 70% and the ＂soil static and dynamic universal triaxial and torsional shear apparatus＂ in Dalian University of Technology as well as by keeping the coefficients of the intermediate principal stress unchanged under an undrained condition during the tests. Based on the experimental re sults, the effects of the principal stress directions and the initial consolidation stress on the undrained monotonic shear behavior of dense sands were discussed, respectively. It has been showed that both the principal stress direction and the initial consolidation stress have considerable influence on the effective stress path and stress-strain relation of saturated dense sand. By contrasting the undrained monotonic shear behaviour of the saturated loss sands, the effects of the relative initial density on the undrained shear behaviour of sands are also discussed, indicating that with the increasing of the angle of the principal stress direction the strain hardening effect of the dense sands tends to de crease gradually, but strain-softening corresponding to the soft sands does not occur.

关 键 词：主应力方向 初始固结应力 密砂 相变状态 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]