车辆荷载作用下土石混填路基累积变形研究

Research on Cumulative Deformation of Soil-rock Concrete Subgrade under Vehicle Load

为研究土石混填路基在车辆通行期间的累积变形发展规律,首先通过开展室内大型静动三轴试验分析了土石混合料的静强度及循环荷载下累积塑性应变发展规律,建立适用于土石混合料的累积塑性应变经验模型并验证了模型的准确性;其次采用数值模拟确定车辆动载对路基不同深度处动偏应力的影响;最后结合工程实用的分层总和法,提出累积变形计算方法,并对典型柔性基层沥青路面在不同车辆荷载作用下长期累积变形进行预测。结果表明:在不同含石量下,静强度随着围压的增加,呈现出线性增长规律;随着车辆荷载的增加,动偏应力也逐渐增大;车辆荷载引起的路基变形在荷载作用初期先迅速增加,随后逐渐趋向稳定;车辆超载对路基累积变形影响显著,当车辆超载率为100%时,路基累积变形为24.65 mm。

In order to study the cumulative deformation development law of soil-rock mixed roadbed during vehicle passage. Firstly,a large static and dynamic triaxial test was carried out to analyze the static strength of soil-rock mixture and the development law of cumulative plastic strain under cyclic loading. An empirical model of cumulative plastic strain for soil-rock mixture was established and the accuracy of the model was verified. Secondly,numerical simulation is used to determine the influence of vehicle dynamic load on dynamic deviating stress at different depths of subgrade. Finally,combined with the practical layering summation method,the cumulative deformation calculation method is proposed, and the long-term cumulative deformation of typical flexible asphalt pavement under different vehicle loads is predicted. The results show that the static strength increases linearly with the increase of confining pressure under different stone content. With the increase of vehicle load,the dynamic deviating stress increases gradually. The roadbed deformation caused by vehicle load increases rapidly at the initial stage of loading and then tends to be stable gradually. The cumulative deformation of subgrade is 24. 65 mm when the vehicle overloading rate is 100%.