Study On Deformation Of Airport Pavement Foundation Under The Action Of Aircraft Loads And Groundwater

With the rapid development of economy,the number and size of airport facilities as an important integrated transport system in our country,are increasing continually.Cement concrete pavement is the main structure form for airport pavement,due to its advantages of high strength,load diffusion ability,stability,anti-fatigue characteristics and low cost,etc,However,the cement concrete is a kind of brittle materials,and the tensile strength is much smaller than the compressive strength.If the airport pavement structure is uncompacted,loose and empty,cracks and short board defects will appear easily in the airport pavement concrete slabs.These defects will directly affect the performance of airport pavement.The aircraft pavement structure will be affected by aircraft loads,the environment and other factors.In this paper,deformation of road foundation under the action of aircraft load and groundwater is studied.The main contents and results are as follows:1.The constitutive model of airport pavement structure was introduced.Road surface and base course models were established by adopting the linear elastic model.Soil base model was established by using Mohr coulomb model.Typical pavement structure model was established with ABAQUS finite element software.2.The characteristics of aircraft load and simulation status were introduced.Based on the characteristics of aircraft load,the simulation formula of aircraft load was established.The user-defined program of aircraft load was written by Fortran language,and repeated loading of aircraft load was realized.The response of airport pavement structure under the action of moving constant load and moving sine load was analyzed.The results showed that,three-dimensional moving sine repeat load is the most rational form of aircraft loading.the foundation’s deformation under the load of the moving sine load type is small.Impacts on the roads’ deformation were inversely proportional to the interval.3.The calculation coupling theory of groundwater seepage and stress was introduced.The user-defined procedure of groundwater level change was prepared by Fortran language,and the change of groundwater level with time was realized.The finite element numerical simulation method was used to analyze the settlement laws of airport pavement foundation under the changing of underground water level.The settlement of airport pavement foundation increased with groundwater level decreasing.The settlement of airport pavement structure would decrease as the groundwater level rising.4.According to the geological data of an airport,the corresponding numerical model was established,and the settlement of airport foundation under the load of the aircraft and groundwater were analyzed.The results show that,under the combined action of the two factors compared with the results of the non-destructive testing by using the ground penetrating radar,the rationality of the model was validated.