Rutting Formation Laws And Interlayer Stress State Analysis In The Turning Area Of Airport Composite Pavement

When the aircraft is turning on the ground,the turning area of airport composite pavement will bear the vertical force and lateral thrust,and coupling with the slow speed,long action time and high temperature weather conditions,which is prone to cause the rutting damage,and threaten the safety of aircraft ground operations.And because of the special location of turning area,the interlayer breaking is more serious,so it needs the special study.In this paper,large-scale finite element software ABAQUS was used to build the composite pavement rutting analysis model under turning area moving load and analyze the influence factors of overlay thickness,turning speed,tire pressure and others of the rutting formation and interlayer stress combining with the temperature field.And the composite pavement skew shear experiment was designed to analyze the interlayer mechanics behavior of composite pavement and get the parameters of adhesive contact model.Specific work and conclusions are as follows:First,the mechanical behavior of the aircraft ground turning was analyzed to get the expression of the lateral force and vertical force ratio.Second,based on the equivalence of deformation and considering the impact of aircraft on the deformation of specific section of composite pavement during the driving process,the turning moving load was turned into the static triangular wave load,to build the composite pavement rutting analysis model.The contact which is based on the traction-separation criterion between the interlayer is adhesive contact and the experiment was designed to get the related parameters.Third,the climatic conditions of Kunming and Urumqi were selected to simulate the composite pavement temperature field.When the depth gets to a certain degree,the temperature will not change with the depth.When the depth gets to 0.75 m,the temperature maintains 19.2? in Urumqi;At the same time,when the depth gets to 0.7m,the temperature maintains 17.9? in Kunming.Fourth,under different weather conditions,the rutting formation laws are almost the same,so the Urumqi was chosen as the representation.Comparing with the straight area,the asymmetry of the turning area rutting is obvious due to the existence of lateral force.The greater the speed is,the bigger the lateral trust will become,although the action time reduces,which will also lead to the asymmetry of the rutting becoming even more obvious.When the speed increases from 5kn to 15 kn,the deformation of the internal side of inside wheel becomes settlement from upheaval.Fifth,the influence of overlay thickness on rutting is very limited when it is greater than 17.5cm;The greater the tire pressure is,the more obvious the rutting will become.Sixth,combining with the rutting model,the interlayer mechanical state of the turning area of composite pavement under the action of the wheel load was analyzed.Due to the existence of lateral forcee in turning area,the horizontal stress of the interlayer is asymmetric distribution.But the vertical stress of the interlayer is almost symmetrical distribution,and because of the impact of horizontal force,there will be some deviation.The greater the velocity(the greater the applied lateral force is)is,the more obvious the asymmetry of the interlayer horizontal stress will become.The thicker the overlayer is,the smaller the horizontal stress will become,which is related to the stress diffusion.It was proposed that the maximum horizontal shear stress of the interlayer should not be greater than the allowable shear stress when designing the composite pavement.