不同初始干密度黄土与混凝土接触面直剪试验

Direct shear test on interface between loess with different initial dry densities and concrete

为提高黄土填方地区基础承载力和沉降计算分析水平,采用大型直剪仪开展了不同初始干密度的重塑黄土与混凝土接触面剪切试验.试验结果表明,随着法向应力的增加,不同土样初始干密度下接触面剪应力-剪切位移曲线由弱软化型逐渐过渡为弱硬化型,最后转变为强硬化型.随着土样初始干密度的增加,接触面剪应力-剪切位移曲线的初始斜率增大,抗剪强度增大,粘聚力先增大再减小,内摩擦角持续增大.土样初始干密度对接触面抗剪强度的影响随法向应力的增加而增大.随着土样初始干密度的减小或法向应力的增加,体应变增大,黄土与混凝土接触面由剪胀逐渐转化为剪缩.

In order to improve the level of calculation and analysis of bearing capacity and settlement of the foundation in loess filling area,shear tests on loess-concrete interface,under various initial dry densities,were performed using a large direct shear apparatus.Test results show that with the increase of the normal stress,the shear stress-shear displacement curve of interface becomes from weak soften form to weak hardening from,and then to strong hardening form.With the increase of the initial dry density of loess,the initial slope of the shear stress-shear displacement curve of interface increases,the shear strength increases,the cohesive force of interface firstly increases and then decreases,while the internal friction angle increases continuously.The influence of the initial dry density of loess on the shear strength of interface becomes more obvious when the normal stress increases.With the decrease of the initial dry density of loess or the increase of the normal stress,the volume strain of interface decreases,and the volume changing rule changes from dilatancy to shrinkage.