材料模量对封闭式防渗墙负摩阻力的影响

The Negative Friction Influence of Material Modulus to the Enclosed Cutoff Wall

为了研究材料模量对封闭式防渗墙负摩阻力的影响,以某黏土心墙堆石坝为背景,建立了有限元模型,坝体材料及覆盖层采用邓肯—张Et-μt模型,防渗墙与覆盖层之间的接触关键采用无厚度接触面模拟,进行了非线性有限元分析。计算结果表明:封闭式防渗墙上的负摩阻力的分布受材料刚度的影响较大,中性点位置随着防渗墙材料刚度地增加在不断地下移,增加到一定刚度时,中性点位置基本保持不变;随着材料刚度地增加,防渗墙上最大负摩阻力值不断的增加,开始增加的速率很快,后期变慢;封闭式防渗墙上竖向应力受负摩阻力的影响较大,材料模量越大,影响越显著。其研究成果可为以后工程设计提供参考。

In order to research the effect of material modulus on the negative friction of the enclosed cutoff wall,taking an clay core rock fill dam as a background,this article has established the finite element model.The filling materials of dam and overburden are adopted by the Duncan-ChangEt-μt model.The interface without thickness has been used in the contact relation between the cutoff wall and overburden.A nonlinear finite element calculation was carried out.The results indicate that the distribution of the negative friction on the enclosed cutoff wall is greatly influenced by the stiffness of the material.Neutral point position is constantly moving down with the increasing of the material stiffness on the cutoff wall.When the stifness is increased to a certain degree,the neutral point position is basically unchanged.With the increase of the material stiffness,the maximum negative friction value of the enclosed cutoff wall is increasing.The rate of the beginning is fast,and the latter is slow.The vertical stress on the enclosed cut-off wall is affected greatly by the negative friction.The more material modulus,the more remarkable the influence is.The research results can provide reference for the future engineering design.