辽西地区黄土的强度与本构特性  

Shear Strength and Constitutive Characteristics of Loess in West Liaoning

作　　者：王常明[1] 马栋和[1] 林容[1] 王科[1] 宋朋燃[1] 

机构地区：[1]吉林大学建设工程学院,长春130026

出　　处：《吉林大学学报（地球科学版）》2010年第5期1104-1109,共6页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(40972171);吉林大学种子基金(40870433)

摘　　要：采用应变控制式三轴仪对取自辽宁西部地区阜新—朝阳段黄土的力学性质进行了试验,获得了黄土的应力-应变关系和抗剪强度的变化规律;采用人工制备不同含水率试样的方法,测试并分析了含水率对黄土本构和强度特征的影响。结果表明:(1)试样的应力-应变关系在不排水剪条件下呈强软化型,表现为脆性破坏;在固结不排水剪条件下随初始含水率的增加由弱软化型向硬化型转变;而在排水剪条件下低含水率时呈软化型,随含水率增加,呈弱硬化型和硬化型。(2)饱水后试样的抗剪强度有很显著的降低:cUU为13.7～363.3kPa时,φUU为18.6°～40.2°;而cUU为0.2～29.6kPa时,φCU则为4°～23.4°。(3)土的有效抗剪强度指标均随含水率增加呈非线性减小的关系,粘聚力与含水率呈半对数函数关系,内摩擦角则与含水率呈幂函数关系。给出了黄土本构的数学模型和黄土抗剪强度指标的取值方法。The stress-strain relation and shear strength characteristics of loess,which is taken from west area of Liaoning,are tested by trixial compression instrument in laboratory.The influence of water content to constitutive relation and shear strength of loess is tested and analyzed by means of remodeled samples with a series of different water content.The results show that（a） the stress-strain relation is softening type under unconsolidated-undrained condition,which exhibits a way of brittle failure.It is changed from strain-softening into strain-hardening with increasing of water content in consolidated-undrained shearing condition.And in the condition of drained shearing test,the stress-strain relation is strain-softening in a low water content,it will be strain-hardening and slightly strain-hardening with increase of water content.（b） The shearing strength of samples will obviously decrease after saturated,namely,cUU is between 13.7 kPa and 363.3 kPa and φUU is between 18.6° and 40.2°,but cCU can be changed from 0.2 kPa to 29.6 kPa,and φCU is from 4° to 23.4°.And（c） there is a nonlinear decreasing relationship of shear strength indexes to water content.The cohesion and the internal frictional angle are changed in a semi-logarithm and a power function with water content,respectively.Consequently,a mathematical model to describe the constitutive relation of loess and a method to determine the index of shearing strength is suggested.

关 键 词：含水率 黄土 应力-应变关系 抗剪强度 

分 类 号：P642.131[天文地球—工程地质学]