Study On Technique Of Treatment For Differential Settlement At The Transition Between The Bridge Abutment And Embankment

Disease often occurs at the transition section between bridge abutment and embankment. The bump at the approach abutment, which is the intuitionistic showing form, is the difficult problem of worrying the highway construction. Against the existing treatment measure, as the capital evaluating objective of the capacity to digest foundation settlement and coordinate deformation, the author, through the simulation analysis, topology optimization, design optimization and testing analysis of engineering example, researches the technique of treatment for differential settlement at the transition section between bridge abutment and embankment.Based on the Visual-Fortran flat, the second development of the large common finite element MARC program is more done. The subroutines is written including three-dimensional and two-dimensional gap element, nonlinear Duncan-Chang model, loose area material model, foundation settlement simulation, and so on.Considering differential foundation settlement mode, the adaptability research for the treatment method of approach slab and replacement material is done. The influence of abutment type on differential settlement is discussed.Because there is dimensional effect for approach reinforcing embankment, the author build the corresponding three-dimensional numerical model. Through the application of three-dimensional gap element for simulating the interface property between filling and reinforcing material, differential connection pattern between abutment and reinforcing means and foundation condition, the author researches the active property of reinforcing treatment technique of geogrid and geocell, discusses the adaptability.Through the application of topology optimization for the first time, based the principle of the least strain energy equivalent to the most stiffness, the structure disposal form of reinforced subgrade body at the transition section between bridge and road is optimized. The result of topology optimization shows that the disposal form of converse trapezoid has the most stiffness, the underside disposal length is not less than 2 meters, the slope from underside to top surface should is not more than 1:1.Based on the three differential foundation mode, the author discusses the influence on the displacement and stress of embankment for design parameters of wedged-shape flexible slab method, including the composite body module, length, space, layer, and so on. Furthermore, the design optimization is done, which provide with the theory guidance for the design method of wedge-shaped flexible slab.According the differential engineering property of applied example, the design plans of wedge-shaped flexible slab at the approach are provided and a large amount of field test and observation is done. The observation information of solid engineering shows that wedge-shaped flexible slab can coordinate the settlement difference between the bridge abutment and embankment, so that the bump phenomenon at the approach abutment is eliminated.