Experimental Study On Fatigue Property Of Tunnel Pavement Under Groundwater And Vehicle Load

As the important section of highway traffic,tunnel often plays the the control effect to the traffic.No matter in the process of the construction or operation,the underground water are inevitable problems.Through the crack in the rock or concrete gravel layer,groundwater infiltrates in the pavement structure,and makes the tunnel pavement immerse in water.Tunnel pavement appears different degree of water fatigue damages with groundwater and traffic loads.From water damage of tunnel pavement not only reduces the driving safety,increase the incidence of the accident,and reduces its service life greatly,but also increases the maintenance costs.The study on water damage of tunnel pavement under groundwater and vehicle load is less.Therefor,this paper considers different water environments and different vehicles loads,combined with numerical simulation and laboratory test,and discusses water damage of tunnel pavement.This paper calculate the change of stress field and displacement field in the different environmental of the tunnel pavement and discusses the effection of the vehicle and pavement void to the water-saturated tunnel pavement;Drawing the results under different conditions of water stability and fatigue curve by the laboratory test.The main contents and results are as follows:①Introduce the failure mechanism of the tunnel pavement by the interaction of groundwater and vehicle load.②Establish the tunnel pavement model by using finite element software ABAQUS,combined with different water environment and vehicle load,different pavement void fraction,research the change rule of vertical stress,transverse stress and vertical displacement in the tunnel pavement stracture under different water environment.In addition also research the vehicle load and void fraction on the influence of pore water pressure under the full water tunnel pavement.Get the change laws of pore water pressure.To provide the reference for the future of tunnel pavement structure design.③Measure the permeability coefficient of the different void ratio specimens by the laboratory tests,and fit relationship equations of permeability coefficient and void ratio.Get the change laws between permeability coefficient and void ratio.④Measure the cleavage strength of asphalt mixture specimen under different water environment and void ratio by improved freeze-thaw splitting test,got theinfluence rule of the water environment and void fraction on the stability of the tunnel pavement structure of water,results show that water environment worse and void ratio have great influence of splitting strength,through immersion rutting test to simulate the full water tunnel damage of pavement under moving load,results show that the overloading of traffic tunnel pavement fatigue has had a huge impact.⑤Through indoor fatigue experiment,on the basis of experimental results,to fit the fatigue life of asphalt mixture specimen under the different void fraction and water environment.got the fatigue life equation and the change rule of Intercept lgk and slope a.Provides the basis of Understand the tunnel pavement structure under the action of groundwater and onboard the fatigue damage.