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为研究沥青面层底部裂缝的应力状态和扩展规律,基于权函数法对含单边裂纹的矩形板权函数进行了理论推导,基于切口小梁的试验模型和单边预切口小梁的三点弯曲试验,研究Ⅰ-Ⅱ型应力强度因子、Ⅰ-Ⅱ复合型断裂判据和裂纹在沥青混合料中的扩展变化规律。结果表明:相同的荷载作用下,切口越靠近加载点,Ⅰ型应力强度因子和最大能量释放率越大,Ⅱ型应力强度因子和开裂角越小;切口越长,最大能量释放率越大,小梁越容易开裂;在切口不对称的情况下对小梁加载出现了Ⅰ-Ⅱ复合型开裂,且起裂荷载随着切口偏离加载点距离的增大而增大。通过理论计算与数值模拟结果的对比,使用权函数法计算小梁Ⅰ-Ⅱ复合型裂纹应力强度因子具有良好的精度。
In order to study the stress state and propagation law of the crack at the bottom of asphalt pavement, the weight function of rectangular plate with unilateral crack was deduced theoretically based on the weight function method. Based on the experimental model of the incision girder and the three points Bending test to study the Ⅰ-Ⅱ type stress intensity factor, Ⅰ-Ⅱ composite fracture criterion and crack propagation in asphalt mixture. The results show that under the same load, the closer the notch is to the loading point, the larger the type Ⅰ stress intensity factor and the maximum energy release rate, the smaller the type Ⅱ stress intensity factor and cracking angle. The longer the notch, the larger the maximum energy release rate, The more the beam is easier to crack, the more cracks appear in the beam when the notch is asymmetric, and the crack initiation load increases with the distance of the notch from the loading point. By comparing the theoretical calculation with the numerical simulation results, the method of weight function is used to calculate the stress intensity factor of composite Ⅰ - Ⅱ crack with good accuracy.