基坑开挖正常固结与超固结黏性土的孔压特性研究  

Pore pressure characteristics of normal and over-consolidated clays due to excavation of foundation pits

作　　者：徐舜华[1] 郑刚[1] 石峰[2] 安璐[1] 

机构地区：[1]天津大学建筑工程学院,天津300072 [2]天津城市建设学院土木工程系,天津300384

出　　处：《岩土工程学报》2008年第S1期159-163,共5页Chinese Journal of Geotechnical Engineering

基　　金：天津市自然科学基金项目(07JCZDJC09800);天津市科学技术创新特别基金项目(07FDZDSF01200)

摘　　要：土体的变形和强度特性取决于土骨架的有效应力状态及其历史,土体中孔隙水压力的精确确定能使我们更好地运用有效应力原理解决基坑等工程实际问题。采用伏斯列夫强度理论中的等效固结应力u/p′_e对三轴试验中的孔压进行归一,证实超固结黏土的孔压u/p′_e与应力比η可近似成双线性关系。正常固结黏土的u/P′_e与η能用通过原点的直线拟合,其系数C与破坏时的摩擦角有关。由这种线性关系推出孔压系数与应力比η的函数关系,与剑桥模型导出的孔压系数相比,可以看出变化趋势是一致的。Deformation and strength characteristics for soils depend on the effective stress and stress history of soil skeleton. The successful prediction of pore pressure in soils makes it possible to solve practical engineering problems more effectively based on the effective stress principle.The pore pressure u in undrained triaxial compression tests was normalized with equivalent consolidation pressure p'_e of the Hvorslev Strength Thoery.A bilinear relationship between u/p'_e and stress ratioηwas validated for isotropical over-consolidated clays.A linear relationship passing through the origin of coordinates between u/p'_e andηwas fitted well for the normally consolidated clays.The slope was related with the frication angle in failure.The formulation of the pore pressure coefficient was deduced by use of the linear relationship.The predicted pore pressure coefficients varying withηagree well with those predicted by the pore pressure formulation deduced from the Cam-clay Model.

关 键 词：等效固结应力 伏斯列夫强度 孔压 正常固结 超固结 

分 类 号：TU411.3[建筑科学—岩土工程]