沥青加铺层反射裂缝动应力强度因子分析

Dynamic Stress Intensity Factor Analysis of Reflection Crack in Asphalt Overlay

当前水泥混凝土路面改扩建工程中广泛应用的方案为加铺沥青面层,其迫切需要解决的核心问题为反射裂缝扩展原理的深入分析。以广西南宁市现有高速公路东环改造二期工程为例,结合动力学理论等开展分析,运用ABAQUS软件研究反射裂缝于动荷载影响下动应力强度因子伴随时间的变化规律,分析得出车辆的快速行驶对于路面裂缝扩展的影响显著减小;车辆轴载的增长会显著加快反射裂缝的扩展;伴随裂缝的不断发展,扩展相同长度可承担的荷载作用次数显著减少;增加沥青加铺层厚度或模量可在一定的程度上减小动应力强度因子数值;伴随应力吸收层厚度或者模量的提升,相应的动应力强度因子变化曲线逐渐减缓;动应力强度因子会伴随接缝宽度的增加不断增大,在扩展后期所产生的影响相对显著。

At present,asphalt overlay is widely used in the reconstruction and expansion of cement concrete pavement.Its urgent core problem is the in-depth analysis of the principle of reflection crack.In this paper,taking the second phase of east ring reconstruction project of the existing expressway in Nanning city,Guangxi Province as an example,the dynamic theory was used to carry out analysis,and ABAQUS software was used to study the variation rule of dynamic stress intensity factor with time under the influence of dynamic load.The analysis showed that the influence of the fast driving of vehicles on pavement crack propagation was significantly reduced.The increase of vehicle axle load will accelerate the reflection crack propagation significantly.With the continuous development of cracks,the number of loads that can be borne by extending the same length decreases significantly.Increasing the thickness or modulus of asphalt overlay can decrease the dynamic stress intensity factor to a certain extent.With the increase of the thickness or modulus of the stress absorbing layer,the corresponding dynamic stress intensity factor decreases gradually.The dynamic stress intensity factor increases with the increase of joint width,and the effect is relatively significant in the later extension period.