循环荷载对粉质黏土力学性质的影响  

Effects of cyclic loading on mechanical properties of slity clay

作　　者：蒋敏敏[1] 蔡正银[1] 曹培[1] 方伟 

机构地区：[1]南京水利科学研究院,南京210024 [2]中交上海航道局有限公司,上海200002

出　　处：《岩土力学》2009年第S2期204-207,共4页Rock and Soil Mechanics

基　　金：交通部西部交通建设科技项目(No.200632800003-06)

摘　　要：通过等压固结静、动三轴试验,研究了渤海湾粉质黏土在循环荷载作用下的动力性质和循环荷载后不排水静力性质。试验结果表明,循环应力幅值比越大,平均轴向应变和轴向应变幅值越大;循环应力幅值比达到0.4时,平均轴向应变和轴向应变幅值随着循环周数增加迅速增大;循环应力幅值比相同,固结应力越大,轴向应变幅值越大,而平均轴向应变越小。在较大的循环应力幅值比下,平均孔压比值和孔压幅值比值随着循环周数的增大会达到稳定;循环应力幅值比越大平均孔压比值和孔压幅值比值均越大;相同循环应力幅值,固结应力越大平均孔压比值越小,而固结应力对孔压幅值比值影响较小。循环荷载的作用会导致循环荷载后不排水剪在q-p’平面上有效应力路径和孔压发展表现出超固结土的性质。A series of consolidated undrained static triaxial tests and cyclic triaxial tests were carried out on undisturbed marine silty clay of Bohai Bay;the cyclic triaxial tests consist of cyclic load and post-cyclic undrained shear 2 stages.It was shown that with the increase of cyclic stress ratio,the average axial strain and single amplitude axial strain become large;when cyclic stress ratio large than 0.4,average axial strain and single amplitude axial strain increase fast with number of cycles;average axial strain increase with confining stress,while single amplitude axial strain decrease with confining stress.Under large cyclic stress ratio,normalized average pore pressure and normalized single amplitude pore pressure come to a stabilization with number of cycles;with large cyclic stress ratio normalized average pore pressure and normalized single amplitude pore pressure become large;with large confining stress normalized average pore pressure become small,while the effect of confining stress on normalized single amplitude pore pressure was unapparent.In post-cyclic undrained shear stage,the effective stress path in q-p' plane and pore pressure exhibit the properties of over consolidation clay.

关 键 词：粉质黏土 动三轴试验 动力性质 循环荷载后静力性质 

分 类 号：TU411.8[建筑科学—岩土工程]