Design Calculation And Experimental Study Of Prefabricated Box Culvert

With the development of highway and the construction of the underground pipe gallery like a raging fire,the box culvert structure have been widely used,but the traditional cast-in-situ box culvert has the disadvantages of long construction period,it is difficult to guarantee the quality,environmental impact and restrict the process of project construction.Prefabricated box culvert,as a new kind of underground structure,has been developed.It has many advantages such as short construction period,high material consumption,good structure quality and strong ability of resisting settlement.Prefabricated box culvert is prefabricated in the special prefabricated field,and then transported to the construction site by prefabricated site for on-site installation and backfill.Prefabricated box culvert has a very broad prospect,it is worthy of our large-scale promotion.But at present prefabricated box culvert is a new structure,no one has a comprehensive and systematic analysis of the structure.At present,most of the relevant designs are based on the finite element numerical simulation and the design experience of the designer,and there is no relevant design specification for guidance.This paper is based on the Nan Chang to Jiu Jiang highway reconstruction project,through theoretical calculation and numerical analysis method combined with the field test,a comprehensive and systematic study on prefabricated box culvert,the variation of mechanical properties of layered soil and under the vehicle load prefabricated box culvert.The main work of this paper:(1)The overall design calculation of prefabricated box culvert.The prefabricated box culvert structure is simplified by the method of structural mechanics,prefabricated box culvert according to the actual working state,the structure to withstand the loads were calculated,finally get the prefabricated box culvert in units of force and related reinforcement calculation.(2)Put forward the construction technology and construction method of prefabricated box culvert,compare and analyze the traditional cast-in-situ box culvert,get their advantages and disadvantages.Through economic and technical comparison,collect the feedback of the construction site,listen to the views of theconstruction side,to further optimize the design and construction method of prefabricated box culvert.(3)The field test of full scale box culvert is carried out on the basis of Expressway Extension Project of Chang nine.Through stratified filling compaction,the measured data of dynamic construction process of box culvert for prefabricated box culvert in the construction process of the soil pressure around the culvert and culvert stress,deformation and settlement rule of box culvert foundation.(4)Based on the finite element analysis software ANSYS,the numerical simulation is carried out,and the two-dimensional plane model and the three-dimensional solid model are established.The 3D solid model is established to simulate the actual situation of the three section box culvert.Through the comparison of two-dimensional plane,three-dimensional entity and measured data,the difference between the numerical simulation and the actual operating conditions is obtained.In two-dimensional and three-dimensional contrast process,trend is the same,but the individual local difference is relatively large,so the force structure of the complex,to establish the 3D model can reflect the structure of the real stress state.(5)During the operation of box culvert,it is affected by many kinds of loads,such as filling pressure,vehicle load,buoyancy,earthquake and so on.Among the loads,the most important is the filling pressure and the vehicle load.By arranging a car and two cars,the vehicle is arranged in different positions,and the influence of the vehicle load on the prefabricated box culvert is studied.(6)In a heavy load prefabricated box culvert in the operation of the inevitable,destructive overloading of prefabricated box culvert,through heavy loading and different position,some typical failure modes of box culvert under heavy load.