循环荷载后饱和海相软黏土不排水静力试验研究  

Experimental study of post-cyclic undrained static behavior of saturated soft marine clay

作　　者：蒋敏敏[1,2] 蔡正银[1] 曹培[1] 

机构地区：[1]南京水利科学研究院,江苏南京210029 [2]河南工业大学土木建筑学院,河南郑州450052

出　　处：《水利水运工程学报》2010年第2期79-84,共6页Hydro-Science and Engineering

基　　金：交通部西部交通建设科技项目(200632800003-06)

摘　　要：通过静、动三轴试验,研究了波浪循环荷载作用对饱和海相软黏土不排水静力特性的影响.试验结果表明:循环荷载作用后,饱和海相软黏土不排水剪在q^p′平面上的应力路径与超固结土相似,循环应力幅值比越大,土体表现的超固结性越强.循环荷载的作用会导致不排水剪阶段孔压的降低,孔压系数表现出超固结土的性质,正常固结土、超固结土和由循环荷载作用导致的似超固结土在不排水剪破坏时的孔压系数均随着平均有效应力比值pi′/pc′的增大而增大.此外,循环荷载作用会导致软黏土不排水强度发生变化,当循环荷载后孔压比值upc/σ1c′小于0.175或循环荷载后弱化指数大于0.70时,不排水强度降低;当循环荷载后孔压比值upc/σ1c′介于0.175~0.256或弱化指数介于0.54~0.70时,循环荷载后不排水强度略有增大.Post-cyclic undrained static behavior of saturated soft marine clay is studied through static and cyclic triaxial tests.Test results indicate that post-cyclic undrained shear effective stress path in q^p′ plane is similar to over-consolidated clay;the larger the cyclic stress ratio during cyclic load,the heavier the over-consolidated property.Post-cyclic undrained shear pore pressure which is lower than normally consolidated clay,pore pressure coefficient after cyclic load which is similar to over-consolidated clay,pore pressure coefficient under failure in normally consolidated clay,over consolidated clay after cyclic load all increase with normalized mean effective stress p ′i / p ′c.Cyclic load affects post-cyclic undrained shear strength,when normalized pore pressure after cyclic load upc /σ ′1c is smaller than 0.175 or degradation index larger than 0.70,post-cyclic undrained shear strength decreases after cyclic load,when normalized pore pressure upc /σ ′1c is between 0.175 and 0.256 or degradation index is between 0.54 and 0.70,and post-cyclic undrained shear strength increase slightly after cyclic load.

关 键 词：饱和海相软黏土 循环后不排水试验 有效应力路径 孔压 不排水强度 

分 类 号：TU411[建筑科学—岩土工程]