Research Of Foundation Treatment Technology For Uneven Settlement Of The Pavement

The uneven settlement after construction of the airport pavement brings a great security risks to the airport security, efficient operation. But because of the complexity of airport engineering and the special request for safety and construction of non-stop flight, the treatment of uneven settlement is problems of airport field service management. Therefore,according to the characteristics of the airport project, a series of theory and technology research for reinforcing the ground and lifting the local road surface in flight gap is very important to improving the quality of airport runway, eliminating the hidden dangers,prolonging the service life of the road surface, and ensuring the safe and efficient operation of the airport. Based on the above background, this paper has carried out the following research work.1 A polymer is selected as the runway ground processing materials, and testes the basic physical and mechanical properties of the polymer, including the variation law of the strength, elastic modulus and maximum expansion force of polymer with density of solidified body, providing the basic parameters for the following research analysis. The test results show that: the yield compressive strength, the elastic modulus and. the maximum expansion force increased gradually with the increase of density.2 According to the physical and mechanical properties of polymer grouting material,the calculation process of elastic modulus and single hole grouting amount of polymer grouting composite foundation is deduced based on the theory of circular cavity expansion and composite foundation, and the influence of grouting parameters( including grouting hole spacing, initial grouting size, grouting depth and distributing mode, on the elastic modulus of composite foundation and the amount of single hole grouting) were studied by orthogonal experiment.3 Due to the dramatic expansion of polymer materials, reinforcing soft subgrade with polymer injection may produce the lifting effect on the runway surface, rigid pavement is brittle material, and in order to avoid the breakage of the panel, we need to study the law of deformation. When strengthening subgrade by the polymer grouting road surface deformation is simulated and analyzed through the numerical calculation software FLAC3 D.The main conclusions are as follows: when the grouting pipe is raised to the top surface of the soil base 0.4m, the road surface deformation by polymer grouting caused is very small,generally less than 1mm, the maximum deformation of the pavement and the influence radius of the deformation are gradually increased With the grouting pipe slowly upward; the increase of the size of the swelling force can increase the maximum deformation and the influence radius of the vertical deformation; when the initial grouting hole radius increases,the deformation of the pavement increases, and the road surface deformation is sensitive to the radius of the initial grouting hole, so the polymer grouting should be carefully designed to ensure that the deformation of the plate is in the range of the limit variable.4 Pavement subgrade reinforcement on the surface of the runway of the lifting effect is not sufficient to recovered subsidence flat area, so it is necessary to realize the goal of balanced adjustment of road surface through the secondary grouting. Using ABAQUS the optimal polymer two grouting position is judged by analyzing the bending stress of the bottom of the plate under the plane load after the two injection of polymer in different locations. and the mechanical properties of the polymer layer under the load of aircraft are studied after leveling the road. The results show that: when using the polymer material selected in this paper, polymer secondary grouting optimal position should be located between the cushion and subgrade. At this time, the aircraft loads under the bottom plate bending tensile stress minimum; with the increase of the elastic modulus of surface layer,base layer, cushion layer, the stress of the polymer top layer decreased gradually in the aircraft loads, which is conducive to maintaining the durability of polymer materials, to ensure good grouting effect.