摘要
在饱和砂土地震液化评估中,多用单向动三轴试验代替双向动三轴试验获得土体的抗液化强度。由于单向激振和双向激振产生的应力路径不同,土的动力特性受应力路径影响,其合理性尚待证明。本文利用双向振动三轴仪分别采用单、双向振动形式进行饱和砂土振动液化试验,对比了相同动剪应力作用下累积孔压和动强度,分析了较大循环振次作用下单、双向振动方式使试样动力响应产生差异的原因,提出了利用单向三轴试验代替双向振动模拟地震循环剪应力获得砂土动力特性的室内试验方法的适用条件。
In evaluating the potential liquefaction of sandy deposits during earthquake,the unidirectional cyclic dynamic triaxial test is often used to determine the undrained shear strength of soil instead of the two-directional test.Because the dynamic stress paths induced by unidirectional cyclic triaxial test and two-directional one are not same,the above suppose is still in question,as it is well known the mechanical behavior of soils is strongly affected by the path.In this paper,both unidirectional and two-directional cyclic triaxial tests are conducted on saturated sand,by means of dynamic triaxial apparatus,which can apply vertical and radial dynamic loading.The development of the pore pressure,residial strain,and dynamic strength during the cyclic loading are discussed.The test results show that the responses of the two-directional tests are quiet different compared with those of conventional unidirectional tests in a high-cycle number.The effect of cyclic loading pattern on the dynamic properties of saturated sand is studied,and the application condition for equivalence of one and two directional tests in simulating cyclic shear stress induced by earthquake is presented also.
出处
《西北地震学报》
CSCD
北大核心
2011年第B08期137-142,共6页
Northwestern Seismological Journal
基金
国家自然科学基金(50708095
50908207)
国家重点基础研究发展计划项目(2007CB714203)
地震行业科研专项(200808022)
浙江省重点创新团队支持计划资助(2009R50050)
关键词
饱和砂
单向振动三轴试验
双向振动三轴试验
动力特征
Saturated sand
Unidirectional cyclic triaxial tests
Two-directional cyclic triaxial tests
Dynamic proerty
