模量不均匀路基上的沥青路面动力响应研究

为研究路基模量的不均匀对沥青路面动力响应的影响规律，首先采用便携式落锤弯沉仪(简称PFWD)对亚-雪公路路基模量分布进行现场测试，分析并总结路基模量的空间不均匀分布特征；进而考虑汽车车体的运动、轮胎的黏弹效应、沥青路面的黏弹性能以及路基模量的不均匀特性，基于D′Alembert原理和黏弹性薄板振动理论，建立了重载汽车-路面-不均匀模量路基耦合动力学模型，并分析了路基不均匀特性、行车速度和后轴轴重对沥青路面动力响应的影响。计算结果表明，路基模量的不均匀性对路面动应变的影响显著。当汽车行驶通过路基不均匀模量区时，后轴产生的基层底应变幅值约为前轴的2倍；当后轴轴载由100kN增加至180kN，基层底应变幅值由62με增加到109με；随着行车速度从5km/h增加至80km/h，基层底部的拉应变幅值增加1.3倍，并逐渐趋于稳定；特别当路基不均匀模量幅值从40MPa降低到0、不均匀模量弦长由1m增加至4m，基层层底拉应变幅的增幅分别可达26%和23%。

Moving truck-induced dynamic response of asphalt pavement supported by subgrade with non-uniform modulus

The main purpose of this study is to investigate the dynamic response of asphalt pavement supported by subgrade with non-uniform modulus. Firstly, the PFWD was employed to test the subgrade of Yabuli-Xuexiang highway, and the spatially nun-uniform characteristics of subgrade modulus were analyzed and summarized. Secondly, the dynamic coupling model of truck-pavement-non-uniform subgrade was proposed considering the movement of truck body, the viscoelastic performance of tire, the viscoelastic properties of asphalt pavement and the spatially nun-uniform characteristics of subgrade modulus. Finally, the effects of nun-uniform modulus, velocity and loading on the dynamic response of the asphalt pavement were discussed and analyzed. Numerical results show that: the nun-uniform subgrade has significant influences on the pavement dynamics. When a truck is running on the nun-uniform subgrade, the strain amplitude induced by the rear axle is about two times of that of the front axle. By increasing the rear axle loading from 100kN to 180kN, the strain amplitude increases from 62με to 109με. With the velocity increasing from 5km/h to 80 km/h, the strain amplitude may increase 1.3 times. By decreasing the nun-uniform modulus from 40MPa to 0 and increasing the nun-uniform ranges from 1m to 4m, the strain amplitude can increase 26% and 23%, respectively.