混凝土层间直剪试验的离散元模拟研究

Discrete Element Simulation of Direct Shear Experiment Between Concrete Layers

混凝土的层间结合情况影响结构整体的剪切性能,因此,需要重点研究混凝土层面的抵抗剪切变形的能力.在采用颗粒流离散元软件模拟整浇混凝土直剪试验的基础上,通过生成随机椭球表示层间缺陷,并将细观缺陷作为弱夹杂考虑到离散元接触模型中,模拟层面直接剪切试验的非线性行为.试验结果表明:正压力越大,试件竖直方向的剪胀越小,而层面破坏时接触的拉裂纹数比例有所增高;非整体浇筑引入的层间缺陷削弱了层面的抗剪强度;层面剪切强度的黏聚力比摩擦系数受层面缺陷的影响更加敏感.本文的研究结果为混凝土层面剪切性能的离散元数值模拟和破坏过程研究提供了参考.

The interlayer bond performance of concrete is the key factor to the shear performance of the overall structure.In this paper,according to the numerical simulation of the direct shear test of concrete bulk by using the particle flow discrete element software,the randomly generating ellipsoids were used to represent the interlayer defects and the meso defects were considered as weak inclusions in the 3D numerical model,then nonlinear behavior of direct shear test of concrete layers was simulated.The results showed that the larger the positive pressure,the smaller the vertical dilatation,and the ratio of the number of tension cracks to the number of shear cracks increased slightly at the time of failure.The existence of interlayer defects introduced by non-whole-casting weakened the shear strength of the layer.The cohesion of the interlayer was more sensitive to the influence of layer defects than the friction coefficient.The research results provide a reference for the research of the numerical simulation and failure progress of the shear performance of concrete layers.