Experiment Study On Dynamic Characteristic Of Pavement And Subgrade

Road transportation plays an important role in the economy all around the world. With the need of heavy load,dense flow rate and high speed,the higher quality of the road structure is demanded. Research results show that the settlements of the road structure mainly come from the consolidation and the accumulative residue settlements under the cyclic loads. Excessive uneven settlements will produce the premature failure on the pavement. And few researches on the interaction of pavement and subgrade have been developed at present. So it is necessary to do a large-scale model experiment in order to research the dynamic response of the pavement and subgrade under traffic loads.This thesis presents a research program on pavement and subgrade structure in the second phase of Guangbei Section of National Highway 108 (Beijing to Kunming). A full-scale model experiment that according to the constructions of Guangbei Section of National Highway 108 has been carried out in laboratory. Sandbag is used to make a flexible wall around the model in order to make the condition of the experiment more closely to the true condition. Through the static and standard traffic cyclic loads,the responses of the pavement and subgrade have been attained. The studies on these responses such as elastic deformations,accumulative settlements and stress have been made under the changed characters of subgrade,such as moisture content,relative compaction of subgrade.The results of the experiments show that superfluous moisture content increases the vertical stress and the settlements of the construction under the similar relative compaction. And under the similar moisture content,lower relative compaction increases the vertical stress and the settlements of the construction either. Comparing the influence to the construction under the changing of these two facts,we can find that the changing of moisture content effects the construction more than the changing relative compaction does. So the immerging of the water and the low quality of the compaction are the reasons on the premature failure of the pavement.