考虑路面结构影响的低路堤动应力响应分析

Research on Dynamic Stress of Low Embankment Considering the Influence of Pavement Structure

以尼日利亚某公路为依托,对考虑路面结构层的砂砾填料低路堤在交通荷载作用下的动应力分布规律进行了研究。首先通过现场测试方法分析了行驶速度和轴重对路基动应力的影响,在此基础上建立三维有限元模型分析了不同路堤高度、不同超载率和不同路基填料模量对动应力分布的影响。现场测试结果表明:车辆的行驶速度越快,应力峰值越小,车重越重,路基内动应力越高,在路面较为平整的情况下,车重是影响路基动应力的主要因素,车速的影响较小。数值模拟结果表明:路基内动应力与路堤高度、超载率和路基填料的模量均成正比,路堤高度由1 m增加到2 m时,路基工作区由1.92 m下降到1.79 m,超载率由0增长到125%,路基工作区深度由1.77 m增加到2.73 m,增了54.2%,路基模量从80 MPa提高到160 MPa时,路基工作区深度从1.77 m下降到1.58 m,下降幅度为10.7%,试验结果表明超载对路基动应力的影响最大。结论为低路堤公路设计提供了参考。

Relying on a highway in Nigeria,this paper studies the dynamic stress distribution of sand-gravel low embankment considering the pavement structure layer under the traffic loads.This paper firstly analyzes the influence of speed and axle loads on the dynamic stress of roadbed through field test.On this basis,a three-dimensional finite element model is established to analyze the influence of different roadbed heights,overload rates and different filling modulus on dynamic stress distribution.The field test results show that the faster the vehicle travels,the smaller the stress peak value,the heavier the vehicle weight,and the higher the internal dynamic stress of the roadbed.When the pavement is flat,the vehicle weight is the main factor affecting the dynamic stress of the subgrade and the vehicle speed has little effect.The numerical simulation results show that the internal dynamic stress of the subgrade is proportional to the height of the embankment,the overload rate and the modulus of the subgrade filler.The subgrade working area decreased from 1.92 m to 1.79 m,the overload rate increased from 0 to 125%,the subgrade working area depth increased from 1.77 m to 2.73 m,with an increase of 54.2%,and when the subgrade modulus increased from 80 MPa to 160 MPa,the subgrade working area decreased from 1.77 m to 1.58 m,which the rate of decrease is 10.7%.The test results show that overloading has the greatest influence on the dynamic stress.The conclusions of this paper provide a reference for the design of low embankment.