含水率对花岗岩残积土邓肯-张模型参数影响

制作了不同含水率花岗岩残积土击实试样,进行一系列固结排水三轴试验.得出在不同围压和不同含水率条件下,花岗岩残积土击实试样在三向应力作用下均呈现鼓胀破坏的变形特征,其固结排水应力-应变曲线均为加工硬化型,与邓肯-张模型的条件式基本吻合.通过邓肯-张模型参数的计算与分析,得知含水率对花岗岩残积土的邓肯-张模型参数整体上影响较大,其中粘聚力受影响最显著,无因次指数n和低围压时的初始变形模量受影响较显著,基本规律为:抗剪强度指标粘聚力、内摩擦角值,初始变形模量及无因次基数K均随着含水率的增大而减小;无因次指数、破坏比随含水率的增大而增大;各参数与含水率关系曲线均在最优含水率处出现拐点,且当含水率大于最优含水率时,其对各参数的影响不同程度地加大.

Influence of moisture content on parameters of Duncan-Chang model for granite residual soil

A series of triaxial consolidation drained tests were done under different surrounding pressures on the granite residual soil samples of different moisture contents.The result shows that under different surrounding pressures and different moisture contents,the granite residual soil samples in triaxial stress present bulging deformation failure characteristics,all stress-strain curves show the property of work-hardening which coincides with the conditional formula of Duncan-Chang model basically.The calculation and analysis of the Duncan-Chang model parameters shows that the moisture content of granite residual soils has a considerable influence on the Duncan-Chang model parameters overall,in which cohesion cis the most significant,and the dimensionless index and initial deformation modulus under small confining pressure are comparatively significant,the basic rule is as follows：with the growth of the moisture content,the shear strength indexes,the initial deformation modulus and the dimensionless radix continue to decrease,while the parameters of dimensionless index and failure stress ratio continue to increase;all parameter-water content curves appear inflection point at the optimum moisture content,when the moisture content is greater than its optimal value,the effect of moisture content on the parameters increases to different degrees.