Study On Failure Mechanism And Structure Design Of Cement Pavement In Open Culvert Section

With the rapid development of my country’s expressway industry,culverts occupy a large proportion in the construction of expressways and are an important part of expressways.Due to the existence of the culvert structure,a rigid-flexible transition layer is formed under the cement concrete pavement.The pavement is prone to disease,which seriously affects the normal operation of traffic and driving safety,and at the same time brings great inconvenience to maintenance.In addition,there are relatively few researches on the working conditions of cement concrete pavement in Minghan section in China.In actual projects,most of them rely on engineering experience to carry out construction,and there is a lack of systematic research.Therefore,the research on the failure mechanism and structure design of cement concrete pavement in open culvert section is of great significance to actual engineering.This article first uses the finite software ABAQUS to establish a finite element model,and analyzes the mechanical response of the factors affecting the cement concrete pavement of the open culvert section.It mainly analyzes the pavement surface stress Secondly factors affecting the open culvert sections of the cement concrete pavement mechanical response analysis,the main of pavement surface deflection and pavement plate stress two indicators were analyzed,and the main conclusions are:culvert depending on the type,size and culverts of the influence of surface stress anisotropy and maximum deflection of the pavement plate increases with the culvert size increases gradually,and the deformation degree is slowing;Increasing the thickness of pavement surface can effectively reduce the stress of pavement surface in a certain range,on the contrary,the increase of elastic modulus of pavement surface will increase the stress of pavement surface.But both can reduce the deformation of the path panel.Increasing the thickness and elastic modulus of pavement base can improve the stress state and deformation of pavement slab to a certain extent.In addition,the change of elastic modulus of foundation has little influence on the surface stress and the maximum deflection of pavement slab.Secondly,the pavement in the case of partial voids in the pavement is researched and analyzed.The pavement at the void is greatly affected by the void,and as the length and depth of the void increase,the stress and deformation of the pavement surface layer will increase;The influence of soil height on the pavement stress,the curve diagram of the relationship between the maximum tensile stress of the top and bottom of the pavement surface layer and different fill heights is obtained.Finally,this article gives four suggestions for the structural design of cement concrete pavement in open culvert section.The main conclusions drawn are as follows:(1)It is recommended that when the distance between the top surface of the culvert structure and the bottom surface of the cement concrete surface layer is less than 1.0m,double-layer steel meshes should be arranged on the top and bottom of the surface layer,with in the range of 1.0m～1.6m.When a single-layer steel mesh is arranged on the top of the surface,and no steel mesh is required beyond 1.6m;(2)The reinforced concrete slab is overlapped between the upper edge of the culvert and the abutment back,which can effectively reduce the surface stress of the road surface;(3)CFG piles are set in the subgrade area between the culvert and the abutment back to form a composite subgrade,thereby improving the bending and tensile resistance of the pavement slab;(4)Setting joints at the most unfavorable load position can effectively avoid the larger pavement stress caused by the unfavorable load position.