Quantitative Analysis And Residual Life Prediction Of Void Beneath Airport Rigid Pavement

Void of slab is the commen disesse of airport rigid pavement,which has been futher studied by many scholars for its unfavorabla forced state and uneasy to be discovered.Most of existing studies focurs on the identification method of void,how to quantitatively analaze the void by existing detection means has became a major problem airport maintenance and management department.Therefore,on the basic of existing research,this paper relys on pavement structure and material paramenters and test data,regard void beneath airport rigid pavement as analytic target.The orthogonal tests were designed,considering the main influence facotors of HWD mearsured deflection and load stress under aircraft load from two angles of range and variance.Then,analyzing the change law of deflectin and stress with varoous foctors,the relationship between HWD test deflection,void size and load stress under aircraft load is established.A method for calculating the structural safety and residul life.1.based on ABAQUS platform,by changing the stiffness of spring element to express different transfer ability of joints.Selecting suitable shape of void beneath slabs and contact model,a finite element model of airport rigid pavement considering joint load transfer capacity and void beneath slab.2.The HWD loading model is established,designing orthogonal test to comprehensively analyze the main influencing factors of deflection,and the control variable experiment is used to analyze the change law of deflection with the main influencing factors.The result shows that,there is little correlation between deflection and elastic modulus of surface course,which is logarithmic relationship to the foundation reaction modulus and spring stiffness,exponential relation to the thickness of slab,quadratic function relation to shape of void beneath pavement.3.Breaking the conventional aircraft loading model,by changing the size of the same aircraft type to simulate different aircraft type.Design orthogonal experiment and control variable experiment to analyze the changing law of load stress with the main influencing factors.The result shows that,there are two critical size for void when the void is located in the middle of the plate edge,one critical size for void when the void is located in the corner of slab.The non-linear regression equation of stress varying with void size and influencing factors is established,the stress correction between different aircraft type is also carried out.4.To optimize the existing specifications in principle is inadequate.A residual life prediction model of void plate structure under mixed traffic volume is proposed,which can take into account the distribution law of wheel tracks and reduce the calculation errors caused by the uniform distribution of wheel tracks and the different calculation results of different design aircraft types in the existing specifications.5.Combining with the design date ang field test of airport A,quantitative analysis of the void beneath rigid pavement and the accuracy of the result is verified by radar test.The load stress of each void plate under design aircraft type is calculated and compared witn the results of split test.Finally,combining with the actual traffic volume information of the airport,the residual life of the void plate structure is calculated,which provides a reference for the maintenance department.