混凝土与混凝土接触摩擦试验及其数值计算模型

摘要

The friction contact between concrete and concrete is studied,and the relationships between shear stress and shear displacement of concrete and concrete are obtained,which is helpful for the numerical calculation of similar shear failure problem.The direct shear test and numerical calculation methods were adopted to analyze the friction contact between concrete and concrete,and the PPR cohesive zone model is used to describe the friction contact between concrete and concrete in numerical modelling.The numerical calculation was carried out and compared with the experimental results.The experimental results and numerical results show that the shear stress can be divided into elastic deformation phase,plastic hardening deformation phase and theoretical plastic deformation phase.The contact surface is still in a high stress state after the shear peak stress,and stress concentration state the damages will appear in local position of concrete structures.Archhard nonlinear power law of friction can describe the relationship between the shear peak stress and the axial stress.The numerical results sh-ow that the shear stress is in good agreement with the experimental results,and there is only small difference between results when the axial load is small.The PPR cohesion model can accurately reflect the shear stress in the shear failure problem and can be used to describe the failure process of similar conditions.%目的 研究混凝土与混凝土接触摩擦特性,得到混凝土与混凝土接触面剪切应力与剪切位移变化关系,为相似剪切破坏问题的数值计算提供依据.方法 采用直剪试验和数值计算两种方法对混凝土与混凝土间的接触摩擦响应进行分析,对试验进行数值计算,并与试验结果进行了对比分析,利用PPR内聚力模型来描述接触面的接触摩擦响应.结果 接触面剪切应力随剪切位移变化过程可分为弹性变形阶段、塑性硬化变形阶段和理想塑性变形阶段;剪切应力达到峰值后,接触面仍处于较高的应力状态,局部位置会出现应力集中态和局部破坏.Archard非线性摩擦幂次准则能够较好地描绘出混凝土与混凝土接触面剪切应力峰值与轴向应力的关系.结论 数值计算剪切应力随剪切位移变化关系曲线与试验结果基本吻合.在轴向荷载较小时数值结果与试验结果存在较小差异.PPR内聚力模型能够较准确地反映剪切破坏问题中剪切应力随剪切位移变化中各阶段的响应,可用来描述相似剪切破坏过程.