Research On Deformation Control And Mechanical Characteristics Of Large Diameter Steel Corrugated Pipe Culvert With High Fill

With the construction of a large number of highways,it is inevitable to cross gully and hilly areas,and high filling projects are inevitable.The increase in the construction scale of high-fill projects has resulted in an increasing number of buried pipe culverts underneath the high-fill,and pipe culvert structures have also emerged;among them,steel corrugated pipe culverts,as a prefabricated structure,have low cost,the advantages of short construction period,intensive factory production,low-carbon and environmental protection,have therefore been widely used in high-filled highway projects.However,there is still a lack of systematic research on the force and deformation laws of large-diameter steel corrugated pipe culverts in high filling sections of highways during the filling construction period and the construction technology based on deformation control.As a result,some large-diameter steel corrugated pipe culverts under high-fill embankments had undergone relatively large deformations during and after construction,which in turn leads to the destruction of the structure itself and the upper subgrade.This paper analyzes and studies the large-diameter steel corrugated pipe culvert under the high-fill embankment constructed according to the traditional technology during the construction and later use of the large deformation problem.First,based on the pipe culvert compression deformation formula,a settlement control method is proposed.The new technology of pipe culvert construction;secondly,based on numerical simulation and field to test,the force and deformation characteristics and vertical earth pressure distribution of large-diameter steel corrugated pipe culvert under the high-fill embankment constructed according to the new technology during the construction stage are studied;Finally,based on parameter analysis,an optimized construction method for large-diameter steel corrugated pipe culverts based on deformation control is further proposed,which provides a reference for the design and construction of similar steel corrugated pipe culverts.The main research results are as follows:(1)Based on the pipe culvert compression deformation formula,a new construction technology of pipe culvert based on deformation control is proposed.This technology can well solve the insufficient lateral stiffness of the backfill soil on both sides of the pipe culvert under the traditional construction method of the high fill embankments.And the degree of compaction is difficult to meet the specification requirements.(2)Based on numerical methods,a comparative analysis of the stress,deformation and earth pressure distribution of steel corrugated pipe culverts constructed according to the traditional and the processes described in this article.The results show that compared with the traditional construction technology,the construction technology proposed to this paper can increase the lateral stiffness of the pipe side fill,which can increase the elastic resistance coefficient and the side pressure coefficient of the pipe side fill,which can effectively reduce the vertical and horizontal deformation of the pipe culvert by 35.1% and 55.0% respectively.(3)Taking a large-diameter steel corrugated pipe culvert in the South moving project of national highway 310 from Luosanjie to Sanmenxia West Section as the research object,the field test is carried out,and the stress deformation characteristics and earth pressure distribution law of the pipe culvert is analyzed.The results show that: with the increase of filling height of pipe culvert,the vertical and horizontal deformation of pipe culvert increases,and the tangential stress of wave crest and wave trough of pipe culvert also increases;during the construction of pipe culvert,the wave crest and wave trough are basically in the compression state,and the peak and wave trough have the largest compressive stress at the pipe top and shoulder respectively.The vertical earth pressure distribution at the top of pipe culvert presents a " V " types distribution law that the earth pressure in the center of pipe top is small and the earth pressure in the edge of pipe sides is large.(4)Single factor control method is used to analyze the influence of the thickness of pipe culvert,elastic modulus of backfill soil at pipe top,elastic modulus of foundation soil and wave size on the stress deformation and vertical earth pressure distribution of steel corrugated pipe culvert.The results show that the thickness of pipe culvert mainly affects the structural stress.When the thickness of steel bellows increases in 4mm to 12 mm,the vertical and horizontal relative deformation and maximum equivalent stress of pipe culvert decrease by 18.9%,6.7% and 48.7%respectively when the thickness of steel bellows is 4mm;the elastic modulus of backfill soil and foundation soil has little effect on the stress and deformation of pipe culvert;When the corrugation size changes in a small waveform(150×50)to a large waveform(400×150),the vertical and horizontal deformation of the pipe culvert will be reduced by 29.0% and 12.8%,respectively,and the maximum equivalent stress will increase by 41.1%;the vertical earth pressure distribution of pipe culvert is not sensitive to the four influencing parameters,which provides an optimization basis for the design and construction of steel corrugated pipe culvert under high embankment.