空隙结构对沥青混合料内部受力状态的影响

Influence of Void Structure on Internal Stress State of Asphalt Mixture

利用ANSYS和蒙特卡罗方法,建立含有不同空隙结构的沥青混合料模型,施加0.7 MPa的竖向荷载后,提取应力应变值,进而研究空隙结构(包括形状、大小、空隙率)的差异对沥青混合料内部受力状态的影响。研究结果表明:X向拉压应变、Y向拉压应变最大值及X向压应力均随空隙边数的减少线性降低,Y向压应力最大值减小更加明显;空隙边缘路径上X应力极大值均出现在空隙的角点,Y向应力在角点处发生突变,最大值可达2.22 MPa,均值为0.59 MPa,尖锐处为易损伤区域;随着空隙变大,应力、应变基本呈增大趋势;空隙率的改变对X向应力与剪应力影响较大,且空隙率一旦超过10%,X向应力与剪应力急剧增大,之后趋于稳定。

The models of asphalt mixture with different void structures are established using ANSYS and Monte Carlo method. After exerting vertical load of 0. 7 MPa and extracting the stress and strain of the models,the influence of void structures（ including shape,size,and air voids） on internal stress state of asphalt mixture is investigated. The result shows that（ 1） the maximum tension and compression strains in X and Y directions and the compression stress in X direction decrease linearly with the reduction of the side number of void,the maximum compression stress in Y direction decreases more obviously;（ 2） the maximum stresses along the sides of voids in X direction appear at the angular point,and the stress in Y direction at the angular point changes suddenly with the maximum change value of 2. 22 MPa,and the mean value of0. 59 MPa,so the damages always appear at the angular points;（ 3） the stress and strain increase with the increase of void;（ 4） the change of air voids has larger influence on the stress in X direction and shear stress,both of them increase rapidly when the air voids exceeds 10%,and then the changes tend to be stable.