Research On Deformation Characteristics Of Roadbed Induced By Rainfall Infiltration And Traffic Loads

With a large number of highway being constructed and put into use, more and more roads, which have not yet reached the design life, are appeared moisture damage diseases and most of them are caused by roadbed diseases. However, more investment does not improve these problems that attracted people’s attention, thus the influence of rainfall and traffic loads on roadbed has become an important research area.In this paper, moisture damage diseases’ investigation at disease-prone section was conducted, and the causes were analyzed. Nondestructive testing technology was used to test pavement’s bearing capacity, rut, roughness and roadbed’s compaction degree, then test results were analyzed for road evaluation. According to compaction evaluation standard, it was found that 87% roadbed exists inadequate compaction. Moisture content test of poor compaction region was showed that soil within a certain range were affected. And based on all of this, the effects of rainfall intensity, rainfall duration, vehicle speed and traffic load on inadequate compaction roadbed were researched using ABAQUS. The study suggests that a good channel for rainfall infiltration is provided by poor compaction region, which promotes formation and development of pavement diseases, and increases the influence range of traffic loads. The roadbed settlement, pore pressure, effective stress and flow velocity are more obvious with the increase of rainfall intensity, and pore pressure changes are concentrated in the first three hours of rainfall duration. Under the condition of same rainfall, the effect of rainfall intensity on pore pressure and flow velocity is greater than rainfall duration. The influence of traffic loads on settlement and vertical stress is more obvious than rainfall. Curves shape of roadbed settlement and vertical stress along running direction under wheels is only related to speed. Heavy vehicles with low speed will cause large vertical displacement and vertical stress at the most unfavorable position especially strong rains, which is extremely detrimental to roads. Therefore, it is necessary to strictly limit the overweight vehicle.