The Dynamic Stress And The Dynamic Construction Control Index Of Highway Subgrade

A long time, for the sustainable development of the national economy, reducingthe occupancy of the highway on land resources and the negative impact of high fillsubgrade, design concept of low fill subgrade have been widely used in highwayconstruction of china.This paper relied on the project of circle freeway of Changshacity, considering low fill subgrade of the ponds and paddy fields and soon.Groundwater throughed capillary action to penetrate the roadbed work area,changing character of the roadbed work area with variation of seasonal and time.Therefore, we made the iquid and plastic limits ,combining low fill subgrade ofthe circle freeway of Changsha city. The results prove that the pond soil and paddysoil not suitable for stuffing，The construction should be first dredging and filling.In order to ensure the quality of embankment,roadbed work in the future to avoidsinking.The paper analysised change law of extra dynamic stress and vibrationdisplacement for subgrade by using of fiber bragg grating instrument and the earthpressure cells to carry out experiments on different regions of filling subgrade.This paper proposed appropriate control index for the circle freeway ofChangsha city by way of using the finite element numerical simulation andestablishing the ANSYS finite element model and asphalt viscoelastic fatiguedamage model. The critical value of overloading the roadbed dynamic modulus andminimum dynamic modulus of low fill subgrade and other control targets wereproposed by comparing the conventional embankment and low fill embankment.The deflection and degree of compaction and dynamic modulus and staticmodulus and other control index of the circle freeway of Changsha city weredetected by using different test methods. Establishing low fill embankment FWDand BB method deflection test analysis of the circle freeway of Changsha city.Results of different test methods haved good correlation by contrasting test analysisof FWD and PFWD and bearing plate method to measure the resilient modulus.Thispaper also studied the correlation of subgrade compactness and deflection ofsubgrade and modulus of resilience, obtaining the detection of low fill subgradecompaction test. Lastly, this paper initially proposed a control subgrade dynamicmodulus method which used of FWD dynamic deflection basin.