K_(0)试验确定土的卸载回弹参数辨析  

Discrimination of soil parameters under unloading with K_(0) test

作　　者：陈龙珠[1] 张思安 CHEN Long-zhu;ZHANG Si-an(Department of Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学船建学院土木工程系,上海200240

出　　处：《地基处理》2024年第2期208-212,共5页Journal of Ground Improvement

摘　　要：基于固结压缩仪和三轴仪进行K_(0)试验测得的数据,本文假设土在卸载回弹过程中表现为非线性弹性,对卸载过程中土的静止侧压力系数与超固结比关系提出了一个适用性良好的拟合函数,并由此推导出土的卸载回弹静止侧压力系数和泊松比算式,两者都会随着竖向应力的减小或超固结比的增大而增大;还推导出土的卸载回弹模量和变形模量的算式,它们都会随着竖向应力的减小和土的回弹指数的增加而减小,其中土的回弹变形模量的降低幅度因受回弹泊松比的影响而更为显著。本文对基坑开挖等卸载条件下地基土应力和变形计算的参数选取具有实用参考价值。Based on the data measured by consolidation compression apparatus and triaxial apparatus in K_(0)test,a curve-fitting function with good applicability for the relationship between the static lateral pressure coefficient of soil and the over-consolidation ratio during unloadingwas proposed.With assumptionof thesoil exhibitingnonlinear elasticity during unloading rebound,formulaswerederivedfor the static lateral pressure coefficient andPoisson’s ratioof soilduring unloading rebound,showing that the two soil properties increase with the decrease of vertical stress or the increase of over-consolidation ratio.Formulas of unloading resilient modulus and rebounddeformation modulus of soil werealso derived,and both ofthe two modulidecrease with the decrease of vertical stress and the increase of swellingindex of soil.The reduction of rebound deformation modulus of soil is more significant due to the influence of the rebound Poisson’s ratio.This article can offerpractical reference in selecting soilparameters for calculation of the stress and deformation of soil under unloading conditions inexcavation.

关 键 词：土的K_(0)试验 卸载回弹 静止侧压力系数 泊松比 回弹模量 变形模量 

分 类 号：TU43[建筑科学—岩土工程]