Study On The Arching And Swelling Of Cement Stabilized Gravel Base Asphalt Pavement In Gobi Area Of South Xinjiang

At present,cement stabilized gravel material is widely used in the pavement subgrade,especially in the desert Gobi and other areas with rich gravel.The performance of cement stabilized gravel material is very ideal when it is applied in most areas,but in recent years,with the increasing thickness of the grass-roots level,a new disease of pavement arching and swelling gradually appears in the desert Gobi and other areas with large temperature difference,and the arching and swelling disease presents the lateral penetration of the road,which seriously endangers the safety of traffic,reduces the performance of the road and increases the maintenance cost.In this paper,for the phenomenon of pavement arch swelling in the Gobi region of South Xinjiang,the research on arch swelling disease is carried out from the following aspects: firstly,field investigation is conducted on several highways where arch swelling disease occurs in the region,and the characteristics of arch swelling disease are counted;secondly,the temperature and displacement inside the pavement structure layer are monitored,and the correlation between the ambient temperature and the temperature of each part of the structure layer is analyzed,and the displacement caused by the temperature change of the structure layer is analyzed Third,the expansion performance of cement-stabilized gravel material is studied;fourth,the displacement and deformation of the structural layer caused by the temperature change of the structural layer is analyzed by the limit element analysis software;finally,the disposal measures of the arch swelling disease are studied,and the arch swelling disease is effectively disposed of.The study shows that the temperature change of the structural layer,the longitudinal displacement of the subgrade and the expansion performance of the subgrade material are the main influencing factors of the pavement arch swelling;through the monitoring of the temperature and displacement of the structural layer and the analysis of the data,it is concluded that the maximum temperature of the cement-stabilized gravel subgrade in the southern border area can be close to 60℃,and the temperature increase makes the cement-stabilized gravel subgrade expand longitudinally and produces the longitudinal displacement,and the experimental section in the warming stage The maximum accumulated longitudinal displacement of the experimental section is 8.6 cm;after the experiment,it is concluded that the expansion coefficient of cement-stabilized gravel mix with grade C-B-3,cement dose of 5%,and aging period of 7 days is 1.751×10-5 in Hotan area of South Xinjiang,among which the grade type has the greatest influence on the expansion coefficient of cement-stabilized gravel material,followed by cement dose;by establishing the finite element analysis model,the theoretical arch swelling disease By establishing the finite element analysis model,the theoretical arch location,arch height and transverse displacement were verified and analyzed,and it was found that the first part of the arch and the highest part of the arch were the middle part of the structural layer,and the maximum upward arch of 9.7cm was generated when the two ends of the 400 m road model were fixed,and the maximum single-side longitudinal displacement was19 cm when one end was fixed;it was found that the method of setting expansion joints in the base layer could effectively deal with the arch swelling disease,and the width of expansion joints should be 20 cm.The width of expansion joints should be 20cm-30 cm,and the spacing of expansion joints should be 150m-200 m according to the actual situation.