不同波形下饱和黏土耦合循环剪切特性的对比研究  

Coupling cyclic tests on saturated clay under different waveforms

作　　者：栾茂田[1] 聂影[1] 杨庆[1] 王猛[1] 孙国忠 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室 [2]辽宁省锦州市建筑设计院,辽宁锦州121000

出　　处：《岩土工程学报》2008年第9期1276-1281,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50579006,50179006);国家自然科学基金重点基金项目(50439010)

摘　　要：海洋波浪荷载在海床内土体中引起的动应力的特点是动应力幅恒定,动主应力方向连续旋转。利用土工静力–动力液压三轴–扭剪多功能扭剪仪模拟海洋波浪的加载形式,针对饱和黏土进行了竖向和扭转耦合循环剪切试验,着重对比研究了在正弦波和三角波两种不同波形条件下饱和黏土的动强度、变形特性、广义临界循环应力比与应力洛德参数。研究表明:在相同破坏振次条件下,正弦波耦合试验比三角波的动强度小,且动剪应力越小,两者动强度的相对降低也越少;在相同动剪应力幅值下正弦波耦合循环剪切的变形大于三角波的变形;耦合循环剪切试验中的广义临界循环应力比受波形的影响,正弦波的广义临界循环应力比小于三角波的;应力洛德参数的变化曲线在不同波形下也有所不同。The cyclic rotation of the principal stress direction with constant amplitude was the characteristics of the cyclic stress in seabed deposit induced by waves. The apparatus for the static and dynamic universal triaxial and torsional shear soil tests was employed to perform stress-controlled cyclic coupled vertical and torsional shear tests under different waveforms of imitated waves. Through a series of tests on saturated clay, the dynamic strength, dynamic deformation behavior, general critical cyclic stress ratio and Lode parameter of stress were systematically investigated under sinusoid and triangular waves. Based on the experimental results, it was observed that the dynamic strength of saturated clay under sinusoid waves was less than that under triangular waves with the same failure cyclic number; the dynamic deformation under sinusoid waves was larger than that under triangular waves in the same dynamic shear stress; the effect of different waveforms on the general critical cyclic stress ratio under sinusoid waves was less than that under triangular waves. Moreover, the variation of Lode parameter of stress was discriminative between two types of waveforms.

关 键 词：饱和黏土 不同波形 耦合循环试验 动强度 广义临界循环应力比 应力洛德参数 

分 类 号：TU432[建筑科学—岩土工程]