【摘要】 为研究旧水泥路面加铺沥青层结构的温度变化对反射裂缝扩展的影响,基于热传导理论和断裂力学理论,运用ABAQUS软件建立非线性瞬态温度场模型,分析连续变温条件下的温度梯度及沥青加铺层反射裂缝扩展规律。研究结果表明:在全天变化中,沥青加铺层正负温度梯度交替出现,且变化幅度大,易诱发温度裂缝;连续变温条件下,剪切型应力强度因子随温度的变化平缓,温度变化非其形成的主因;但张开型应力强度因子随温度的变化显著;在沥青层降温收缩阶段,尤其在17:00~22:00时段,当降温幅度越大,温度越低,则张开型应力强度因子越大,越易引起沥青层开裂;裂缝长度越长,应力强度因子SIFs越大,尤其是张开型应力强度因子峰值,裂缝长度越长越易加速张开型裂缝扩展。更多还原

【Abstract】 With the purpose to know better about the development of reflective crack of the asphalt overlay on the old cement concrete pavement in the actual thermal environment,full consideration was given to the heat conduction theory and fracture mechanics. The model of nonlinear transient temperature field in asphalt overlay on the existing cement concrete pavement was simulated by ABAQUS finite element software. And then,the research of the diurnal variation of temperature gradient and the development of reflective crack of the asphalt overlay on the old cement concrete pavement is carried out. The results show that during the day,the positive and negative temperature gradient of the asphalt overlay appears alternately and vary within wide limits,which is more easily to cause the thermal cracking. In addition,under the thermal environment,the shear stress intensity changes gentle with temperature,which suggests that the change of temperature may not be the main cause of its formation. However,compared with shear stress intensity factor,the type I intensity factor changes greater with the temperature of asphalt layer. Meanwhile,in the stage of cooling and shrinkage of the asphalt layer,especially from 17: 00 to 22: 00,the greater the temperature drop range is,the lower the temperature is,the greater the type I intensity factor is,which is more easy to cause the cracking. The longer the length of the crack is,the greater the intensity factor SIFs grow,especially for the Peak value of the type I intensity factor.更多还原