荒漠区沥青路面拱胀病害机理及影响因素分析

Analysis on Mechanism and Influencing Factor of Asphalt Pavement Arch Expansion Disease in Desert Area

针对阿勒泰荒漠区S21阿乌高速出现的沥青路面拱胀病害问题,对其机理及影响因素进行分析。经现场调查与室内试验,分析沥青路面拱胀病害成因。以调查结果为基础,运用Kirchhoff薄板理论与有限积分变换法理论推导基层拱胀临界应力计算公式,分析沥青路面拱胀病害力学机制,确定基层拱胀临界应力值。应用Abaqus建立道路有限元模型,分析基层施工温度、膨胀系数、回弹模量及路表最高温度等因素对基层纵向最大应力与路面最大拱起高度的影响,并基于基层拱胀临界应力值给出相应建议。研究认为:S21阿乌高速沥青路面拱胀病害是水泥稳定砾石基层在过大的温度应力作用下发生拱起破坏的结果。考虑实际道路情况,S21阿乌高速水泥稳定砾石基层拱胀临界应力值为3.49 MPa。当基层纵向最大应力大于基层拱胀临界应力值时,基层将会发生拱起失稳破坏。基层施工温度、膨胀系数及路表最高温度均为基层纵向最大应力与路面最大拱起高度的敏感因素,而基层回弹模量对路面最大拱起高度无明显影响。建议将基层膨胀系数控制在2.8×10^(-5)℃^(-1)以内,基层回弹模量控制在1400~2200 MPa以内。

Due to the problem of asphalt pavement arch expansion disease in S21 Altay-Urumqi expressway in Altay desert area,the mechanism and influencing factors are analyzed.Through the field investigation and test,the causes of asphalt pavement arch expansion disease are analyzed.Based on Kirchhoff’s thin plate theory and finite integral transformation method theory,the calculation formula of critical stress of base arch expansion is derived.The mechanical mechanism of asphalt pavement arch expansion disease is analyzed,and the critical stress value of base arch expansion is determined.The finite element model of the road is established,and the influence of the factors(e.g.base construction temperature,expansion coefficient,resilient modulus and maximum temperature of the pavement surface)on the maximum longitudinal stress of the base and the maximum arch height of the pavement surface are analyzed.Based on the critical stress value of base arch expansion,the corresponding recommendations are given.According to the study,the asphalt pavement arch expansion disease in S21 Altay-Urumqi expressway is the result of arch damage of the cement stabilized gravel base under excessive temperature stress.Considering the actual road conditions,When the maximum longitudinal stress is greater than the base arch expansion critical stress value,the base will occur arch instability damage.The base construction temperature,expansion coefficient,resilient modulus,and maximum temperature of the road surface are all sensitive factors for the maximum longitudinal stress of the base,while the resilient modulus of base has no significant effect on the maximum arch height of pavement.It is suggested that the base expansion coefficient is within 2.8×10^(-5)℃^(-1),and the base resilient modulus is 1400-2200 MPa.