旧水泥路面沥青加铺层抗裂机理的理论分析

Theoretical analysis of anti-crack mechanism of worn concrete pavement overlaid with asphalt

反射裂纹是旧水泥路面加铺后产生的主要病害之一.以断裂力学理论为基础,建立含裂纹水泥路面加铺结构的理论分析模型.采用傅里叶积分变换理论对平面问题位移控制方程进行求解,引入位错密度函数,通过公式推导建立奇异积分方程,再应用Lobatto-Chebyshev求积公式求解奇异积分方程,得到水泥路面内任一点位移、应力和应力强度因子的解析表达式及数值解.通过对比加铺前后旧水泥路面中裂纹尖端应力强度因子的变化情况,分析加铺层对于阻止裂纹扩展发挥的作用.通过分别对比不同裂纹长度、加铺层弹性模量在车辆荷载作用下应力强度因子的计算结果,研究影响加铺效果的主要因素.

Reflection crack in worn concrete pavement with overlay is one of its main diseases.A theoretical analysis model of concrete pavement with overlay is built up on the basis of the theory of fracture mechanics.Fourier integral transform theory is used to solve the controlling equation of planar displacement,the dislocation density function is introduced to set up a singular integral equation,and then the LobattoChebyshev integration formula is used to solve it and get the analytic expressions and numeric solutions of stress,strain,and stress intensity factor around the crack tip at any points in the pavement.By comparing the variation of stress intensity factors at crack tip before and after overlay addition onto the pavement,the function of overlay addition for restriction on crack progression is analyzed.In addition,by comparing respectively the calculated crack lengths and elastic moduli of the overlay generated by vehicle loads,the main factors affecting the overlay effect are investigated.