南宁非饱和膨胀土在剪切条件下剪应力松弛特性的试验研究  

EXPERIMENTAL STUDY ON SHEAR STRESS RELAXATION CHARACTERISTICS OF NANNING UNSATURATED EXPANSIVE SOIL UNDER THE CONDITION OF SHEARING

作　　者：许豪[1] 肖宏彬[2] 滕珂[3] 

机构地区：[1]中国石化集团河南石油勘探局勘察设计研究院,河南南阳473132 [2]中南林业科技大学,长沙410004 [3]中南大学土木建筑学院,长沙410075

出　　处：《工业建筑》2011年第4期92-96,91,共6页Industrial Construction

基　　金：国家自然科学基金项目(50978097);湖南省自然科学基金项目(08JJ3092)

摘　　要：针对南宁膨胀土进行一系列室内剪应力松弛试验,探讨南宁非饱和重塑膨胀土在直剪条件下的剪应力松弛特性。试验结果表明:在不同含水率条件下的剪应力松弛曲线均属于非完全衰减型,剪应力逐渐减少并趋于一个稳定值;松弛曲线可以明显地分为三个阶段:加速松弛阶段、匀速松弛阶段和稳定松弛阶段;含水率越高,应力-应变等时关系曲线的非线性程度越大,土体达到破坏的位移值越小。建立的K-H体本构方程的拟合曲线与实测曲线有较好的拟合度,表明该本构模型能较好地反映南宁非饱和重塑膨胀土的剪应力松弛特性。On the basis of a series of indoor shear stress relaxation tests for Nanning unsatruated manipulated expansive soils,shear stress relaxation characteristics of the unsaturated manipulated expansive soils under the condition of direct shearing were researched.The results show that shear stress relaxation curves fall into non-complete decay type under different water content,and the shear stress gradually decreases and tends to stable values.The relaxation curves can be divided into obvious three stages： accelerate relaxation stage,uniform speed relaxation stage and stable relaxation stage.The nonlinear extent of stress-strain isochronal relationship curves is increasing gradually with an increase in the water content,and displacement values of damage of soil body are becoming smaller.The fitting curves of K-H constitutive equation well agreed with those of the observed data,which is able to reflect shear stress relaxation characteristics of Nanning unsaturated manipulated expansive soil.

关 键 词：膨胀土 剪应力松弛 非线性 K-H模型 

分 类 号：TU411[建筑科学—岩土工程]