Research On The Spatial Dimension Vertical Pressure And Structural Type Optimization Of High Road Embankment Culvert

In view of the high-grade road construction increasing in the mountainous area,highroad embankment and high road embankment culvert which the depth of fill is higher than 20meters will inevitably increase,for the purpose of guarantee the quality of road service.However,part of these high fill culverts suffer different destruction during the construction oroperation process due to lacking of reasonable calculation theories and methods of the earthpressure,maintenance costs increased in this situation;some high embankment culvertstructural result in a waste of resources because of conservative design.By analyzing the theories and methods of the actual high embankment culvert earthpressure calculation which are in force.The discussion on the top vertical soil pressure of theculvert which corresponding with the top face of the embankment is based on the perspectiveof plane.The author attempts to explore the high embankment culvert stress from theperspective of space and has found the vertical soil pressure calculation theory and method inorder to accord with actual culvert stress situation.The main content of this article is divided into six parts:(1).First step,throughresearching the theories and methods of the top soil pressure of the culvert.The discussion onthe top vertical soil pressure of the culvert in the center line of the road is based on the 2D.The theories and methods are one-sided,because the vertical soil pressure calculation theoryand method does not match with actual culvert stress situation.It is very important to researchembankment culvert by the force of the three-dimensional space.(2) Under the differentprograms of Culvert filling,through laboratory test,found around the culvert with a highdegree of filling of the trend along a different vertical position.(3).The establishment of finiteelement model is based on laboratory test,in order to test the accuracy of finite element model,it is important to imitate numerical simulation by the software ABAQUS.(4).We can deductthe vertical soil pressure calculation theory under vertical space.This theory has beenconsidered under concentration stress effect and soil arch stress effect.The theory also hasbeen tested through laboratory test,numerical simulation and spot test.(5).In order to find theways and means of raising the bearing capacity of the high embankment culvert,we canresearch the foundation bearing capacity through laboratory test and theory study.(6).Through researching on culvert,foundation,soil filling as a whole.The Optimized structurewill be work out.Through laboratory test,numerical simulation,theoretical calculation and verification offield test,the author has an in-depth and systematic studied on the high embankment culvert earth pressure calculation theory,and has found the following conclusions:(1) The top vertical soil pressure of the culvert corresponding to the top face of theembankment①At the beginning of filling,the top soil pressure of the culvert is increasing linearlyalong with the height of filling,and it is similar to the academic soil column of earth pressure(P=γ~H) calculated.With the height of fill increasing,culvert top soil pressure graduallybigger than soil column of earth pressure (P=γ~H),which fully reflects the effects of stressconcentration,and soil arch effects at this time is taking shape.When filling up to a certainheight,soil arch effect gradually exceeds effect of stress concentration,so that the top earthpressure of the culvert is gradually less than soil column of earth pressure (P=γ~H).②The vertical soil pressure of embankment slope corresponding to the roof space isbigger than soil column pressure.③The vertical soil pressure of embankment edge corresponding to the roof space is lessthan soil column pressure.The top vertical soil pressures of the culvert corresponding to the top face of theembankment provide a basis for the structural optimization of embankment culvert.(2) The filling method for high embankment culvert peripheral region①On both sides of the culvert at least 2.5 times the original scope of the embankmentground layer should be filled with gravel (gravel soil,etc.),which also include the originalscope of the culvert in the ground,and then proceed to impact compaction,for its degree ofcompaction achieve 96%;②Small modulus of deformation material should be used for filling soil on both sidesof culvert(such as gravel)and be filled to the top of the culvert,so that the top of fillingculverts can form a certain"support force"unloaded arch,and generate a soil arch effect.Also the construction process should be carried out in hierarchical compaction,to reach oroutweigh the degree of compaction of roadbed construction requirements.③The filling materials and degree of compaction on the top of the culvert:it is thatfilling the material with big deformation modulus (such as sand or gravel) in roadembankment top surface width that corresponding top domain of the culvert should no morethan 2 m,then its upper layers following the requirement should be carried out compaction bylayer,to promote the filling soil above the culvert a certain form"supporting force"unloading arch,and generate a soil arch effect. (3) The relative improvement of the ways and means of the foundation bearing capacityfor high embankment culvert.①The embedded depth of foundation calculation is according to the height from the topsurface of culvert to the bottom of foundation when using criterions to calculate culvertfoundation bearing capacity.②Using the filling method for high embankment culvert peripheral region.(4) The type of the structural optimization of high embankment culvert.①Interaction between culvert and soil should be considered in structure of the culvertwhen culvert foundation and fill are regarded as an interaction common system.The analysisshowed that hinge situation is superior to rigid connection in stress performance.②Inverted arch form is designed for the culvert floor and it could promote the stresscharacter of the culvert structure.