Experimental Study On Modulus Of Resilience Of Subgrade In The Seasonal Freezing Region

Under the repeated action of freezing and thawing, the strength of subgrade was decreased much obviously than which completed early in the seasonal freezing region,and it often creat freeze-thaw cracking,frost boiling,local subsidence and other damage in the traffic load,which will serious impact on road performance.In order to rational design of the subgrade and pavement in the seasonal freezing region,it is necessary to conduct the research on the variation of modulus of resilience of subgrade under the action of freezing and thawing.According to massive laboratory experiments,this article has conducted the research on the variation of modulus of resilience of subgrade under the repeated action of freezing and thawing.1. Under the same condition of soil,the test of modulus of resilience of rigid loading board of tube and unconfined cylinder specimens have been carried on separately,which has established the relationship of the modulus of resilience between the laboratory experiments of rigid loading board of tube and unconfined cylinder specimens.2. Based on different moisture content and freeze-thaw cycling times,rebound modules test has been carried out in unconfined cylinder specimens of different subgrade soil,and it has been analyzed the mechanics feature which effected by moisture content and freeze-thaw cycling times,which yield the variation of rebound modules of the different soil with the moisture content and freeze-thaw cycling times.3. The article has analyzed the attenuation laws between the stable value of rebound modules with freeze-thaw cycling and the value of rebound modules without freeze-thaw cycling,studied the relationship between attenuation variation and moisture content.It has been presented the reduction function of rebound modules of subgrade under the freeze-thaw cycling function,on the basis of which brings out the determined methods of soil subgrade modulus of resilience in seasonal freezing region.This research provides a basis for reasonable determination of soil subgrade modulus of resilience with freeze-thaw cycling function in seasonal freezing region.It has the reference value on the road design research in the seasonal freezing region and also provided the theoretical basis on the further study on the coupling of the heat-moisture-stress field.