软土主次固结划分及影响因素探讨  

EXPLORATION ON DIVISION OF PRIMARY-SECONDARY CONSOLIDATION AND INFLUENTIAL FACTORS WITH SOFT SOIL

作　　者：雷华阳[1,2] 王学超[1] 丁小冬[1] 刘景锦[1] 陈丽[1] 张文振[1] 

机构地区：[1]天津大学土木工程系,天津300072 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300072

出　　处：《工程地质学报》2014年第3期489-497,共9页Journal of Engineering Geology

基　　金：国家自然科学基金项目(51078262);国家重点基础研究发展计划(973)计划项目(2010CB732106);天津市软土特性与工程环境重点实验室开放课题(2011SCEEKL003)资助

摘　　要：主、次固结的划分是正确预测和分析软土地基变形并采取有效工程措施的关键问题之一。利用单向固结仪和三轴剪切仪,对天津典型软土进行了一系列一维压缩次固结试验和三维次固结试验,得到荷载、孔隙比、孔隙水压力、体积应变和时间的关系曲线。试验结果表明:由孔隙水压力消散确定的主次固结划分时间滞后于体应变划分时间;所提出的采用应变速率和应变关系来划分主次固结的方法可以合理地适用于各种荷载条件;主固结时间随试样高度的增大而增大,随排水条件的加强而减小;随着荷载等级的增大,主固结时间延长;当荷载小于结构屈服应力时,加荷比对主次固结划分的影响较小,当荷载大于结构屈服应力时主固结时间随着加荷比的增大而延长;预压后土体的主固结应变与总应变的比值比无预压的情况增大30.7%,且该值随着预压荷载的增大而增大。Division of primary-secondary consolidation is one of the key problems of prediction and analysis foundation deformation of soft soil correctly and taking effective engineering measures.A series of one dimensional compression secondary consolidation tests and three-dimensional secondary consolidation tests are performed by using unidirectional consolidation apparatus and triaxial shear apparatus for the typical soft soil in Tianjin.Load, pore ratio and pore water pressure,volume strain and time relationship are obtained.The test results show that：the division point of primary-secondary consolidation should be before the pore water pressure dissipation completely.A new method according to the strain rate and strain curve to differentiate the primary and secondary consolidation is founded.And the new method is suitable for all kinds of load.Primary consolidation time is prolonged along with increasing sample height while shortened along with the strengthening of drainage condition.With the increase of the load level,primary consolidation time is prolonged.When the load is less than the structure yield stress,the division of the primary-secondary consolidation is less affected by load ratio.While the load is greater than the structure yield stress,the primary consolidation time is prolonged along with the increase of load ratio.The ratio of the primary consolidation strain and the total strain after preloading is increased 30.7%than that of no preloading. The ratio increases along with the increase of the preloading load.

关 键 词：软土 次固结 主固结 划分标准 

分 类 号：TU47[建筑科学—结构工程]