Dynamic thermo-mechanical responses of road-soft ground system under vehicle load and daily temperature variation

A complete road-soft ground model is established in this paper to study the dynamic responses caused by vehicle loads and/or daily temperature variation.A dynamic thermo-elastic model is applied to capturing the behavior of the rigid pavement,the base course,and the subgrade,while the soft ground is characterized using a dynamic thermo-poroelastic model.Solutions to the road-soft ground system are derived in the Laplace-Hankel transform domain.The time domain solutions are obtained using an integration approach.The temperature,thermal stress,pore water pressure,and displacement responses caused by the vehicle load and the daily temperature variation are presented.Results show that obvious temperature change mainly exists within 0.3 m of the road when subjected to the daily temperature variation,whereas the stress responses can still be found in deeper places because of the thermal swelling/shrinkage deformation within the upper road structures.Moreover,it is important to consider the coupling effects of the vehicle load and the daily temperature variation when calculating the dynamic responses inside the road-soft ground system.

冻融循环和动荷载耦合作用下路基土动回弹模量试验

为了考虑浅层地下水在路基土冻融循环过程中的影响,自主研发了多功能冻融循环试验系统,模拟冻结过程中路基土存在地下水补给的工况,并对冻融循环后的试样进行大量动三轴试验。系统研究了冻融循环次数、压实度、围压、循环偏应力、加载频率、初始含水率对土体动回弹模量的影响。结果表明,路基土动回弹模量随着循环偏应力、冻融循环次数、初始含水率的增加而减小,相反,随着压实度、围压、加载频率的增加而增加。此外,基于试验数据建立了考虑冻融循环和应力状态的动回弹模量修正预估模型,模型计算结果表明,修正的预估模型具有较高的精度。本研究可为地下水补给工况下的冻融循环研究和路基土动回弹模量研究提供相应参考。