含水率对郴州煤系土邓肯-张模型参数的影响

Influence of Moisture Content on the Parameters of Duncan-Chang Model of Chenzhou Coal-Bearing Soils

以郴州地区典型煤系土为研究对象,制备了不同含水率的重塑煤系土试样进行三轴固结排水试验,计算得到了各含水率煤系土邓肯-张模型参数并分析了含水率对模型参数的影响。结果表明：试样均呈鼓胀破坏特征,无明显的峰值;试验初期,煤系土试样处于线弹性变形阶段,当应变达到3%～5%时,逐渐进入弹塑性变形阶段;含水率对煤系土邓肯-张模型各参数影响程度不同,其中c值受含水率影响显著,参数c、、Ei、K、Kb随含水率的增加而减小,参数m、n、Rf随含水率的增加而增大;试样含水率在15%-25%时,破坏比Rf值均在0.9以上,但并未发生剪切破坏,表明煤系土应力-应变关系呈硬化型特性。

The influence of moisture content on the parameters of Duncan-Chang Model of Chenzhou coal bearing soils was triaxial tested under consolidated undrained conditions.The typical remolded Xhenzhou coal-bearing soil samples were prepared and tested with different moisture contents.Test results indicate that,failure pattern of all test samples were bulged and no obvious peak failure stress observed.The elastic deformations at the initial test stage were demonstrated and plastic deformations were appeared when the strain reached 3% ~5%.The influence of moisture content on parameters of Duncan-Chang Model parameters are different.The cohesion c is significantly affected by the moisture content.Values of parameters c,Ei,K and Kb decrease with the increase of moisture content,whereas,values of parameters of m,n,Rf increase with the increase of moisture content.The failure ratio Rf is greater than 0.9when the moisture content of sample are within 15%-25%.The strain hardening characters are shown since no obvious shear failures were observed even if the Rf is greater than 0.9.