Study On Vertical Soil Pressure On Top Of Trench-Buried Culvert Influenced By The Deformation Of Culvert

The culvert is widely used in projects, such as water conservancy, railway, highway, etc, as well as in municipal engineering and energy sources. Especially in civil engineering, its importance of security becomes obvious day by day for their excessiveness in quantity and the proportion of the work.But at present,the procedures exsiting on designing and constructing culvert are very irrational.Such as there are many formulas about vertical soil pressure on the top of trench-buried culvert, but there are so many limitations existing in them.Meantime, existing theories relating to culverts concentrate on the manifestation and caculating of the earth pressure,neglecting the culvert itself as load-carring structure and its deformation. In this paper, based on the model testing in the house described in [73]and[74], researches is done deeply and systematically on the vertical soil pressure on the top of culvert influenced by the deformation of culvert using finite element analysis.The objects of the model testing are trench-buried rigid culverts based on stiff foundation and sand soil. It is to get the displacement contour of backfilled soil in different height and section observing the settlement of every sign buried in soil, and to gain the distribution rule of the vertical soil pressure on the culverts with quadrate and circular section measuring the distortion of pressure cells which buried around culvert.Then the connection between the coefficient Ks and the height of backfilled soil H, width of groove bottom B and gradient m are analyzed.To verify the reliability of ANSYS for calculating the vertical earth pressure on the top of culvert, this paper simulate the model testing with parameters by the software ANSYS and gain the vertical soil pressure coefficient on the top of culverts and the displacement field of soil. It is obvious that the software is reliable of contrasting with the testing results.Based on the above simulation of stiff foundation and stiff culvert, the paper explores the earth pressure influenced by the deformation of culvert expanding simulation range. The results show that: when H/D≤10, the deformation of culvert increases with the height of backfilled soil in the falling. The vertical earth pressure appears concentration at the top of rigid culverts. The vertical earth pressure on culverts which appears larger in middle and smaller in sides is basically steady at the scope of 0.40D from the central axes.In rectangular groove,while B/D=2～3, the distribution of the earth pressure of culvert appears larger in middle and smaller in sides when a>0.62,the earth pressure is approximately uniform when a is between 0.18and 0.62, the distribution of the vertical earth pressure of culvert appears is smaller in middle and larger in sides when a<0.18; while B/D=3～7, the distribution of the earth pressure of culvert appears larger in middle and smaller in sides when a>0.62, the earth pressure is approximately uniform when a is between 0.29 and 0.62, the distribution of the vertical earth pressure of culvert appears is smaller in middle and larger in sides when a<0.29.In trapeziform groove, while B/D=2 and m is between 0.25and 0.75, the distribution of the earth pressure of culvert appears smaller in middle and larger in sides when a<1.00,the earth pressure is approximately uniform when a is between 1.00and 2.88, the distribution of the earth pressure of culvert appears is larger in middle and smaller in sides when a≥2.88.In conclusion, this paper focuses on studying the vertical soil pressure on the top of culvert influenced by the deformation of culvert with finite element analysis and get some results which are the references to coach the engineering design and construction. Although the results are significant to the choice of culvert martiaral and optimization of culvert designing, it needs to be verified in practice.