考虑加卸载时长的路基土动态回弹模量测试方法及试验研究

Test method and experimental study on theresilient modulus of subgrade soil considering the loading and unloading duration

路基土动态回弹模量是沥青路面结构设计中的重要参数,准确获取路基土动态回弹模量一直是道路工程领域的重要研究课题之一。在调研路基土动态回弹模量测试方法相关成果的基础上,通过有限元数值计算、试探性试验,建立考虑行车荷载加卸载时长影响的路基土动态回弹模量测试方法;选取两种典型的路基土,开展考虑行车荷载加卸载时长的动态回弹模量试验。试验结果表明:两种土质动态回弹模量随围压增大而增大,随循环偏应力、加载时长的增大而减小;随着加载时长的增加,路基土动态回弹模量减小可达34.6%,加载时长的影响不容忽视;不同加载时长下,路基土动态回弹模量随围压、循环偏应力的影响规律基本一致。

The dynamic resilient modulus of subgrade soil is an important parameter in design of asphalt pavement structure.Accurate acquisition of the dynamic resilient modulus of subgrade soil is always one of the important research subjects in the field of road engineering.In this paper,based on the investigation of the relevant results of domestic and foreign subgrade soil dynamic resilient modulus testing methods,a dynamic resilient modulus testing method for subgrade soil considering influence of the loading and unloading duration has been established through finite element numerical and exploratory tests.Two kinds of typical subgrade soils were selected to carry out dynamic resilient modulus tests considering the loading and unloading duration of the vehicle load.The experimental results show that the dynamic resilient modulus of the two kinds of soil increases with the increase of confining pressure,and decreases with the increase of cyclic deviatoric stress and loading time.With the increase of loading time,the dynamic resilient modulus of subgrade soil can be reduced by 34.6%,and the influence of loading time cannot be ignored.Under different loading time,the influence law of the dynamic resilient modulus of subgrade soil with confining pressure and cyclic deviatoric stress is basically same.