| With the development of economy in our country, water conservancy、 road and railway construction is increasing, especially highway and railway construction in mountainous, at the same time culvert has been applied popular. The calculation theory and methods of earth pressure under embankment on the top of culvert is varied. Therefore, there has no a unified one.Because of the relative limitation of each method, the calculation result of structure is not the same. With the underestimate of culvert structure, the frequent failure is the cause that engineering can’t be normal used. On the contrary, if the engineering design is too conservative, engineering economy is not reasonable.Embankment culvert structure belongs to the three-dimensional structure. The soil pressure around the culvert has a heavily effect on culvert safety. It is the vital factor to culvert structure safety that the vertical earth pressure locates on culvert. The author tries to adopt the method of three-dimensional finite element analysis to study the embankment culvert from space for this problem. In this paper, the breakthrough point is bases on embankment slope. Under the condition of the rigid foundation and soft foundation case, the change rule of the vertical earth pressure on the top of culvert is studied with different embankment slope. In this paper, the research content is as follows:(1) Based on the large commercial finite element analysis software ANSYS, three-dimensional finite element model is established. On rigid foundation, the distribution rule of the vertical earth pressure on box culvert is analyzed with the case of different slope、different filling height and slope high. The results show that the coefficient of earth pressure is greater than1and the stress concentration phenomenon is obvious. Filling a certain gradient and total height, the coefficient of earth pressure with the increase of fill height shows a trend of decrease after the first increase. Filling a certain gradient and fill height, with the increase of the high of slope, the coefficient of earth pressure has showed a trend of increase nonlinear finally tends to be stable. A certain high of slope, within a certain range of filling height, the greater of gradient, the greater the coefficient of earth pressure is. The coefficient of earth pressure difference is very small out of the range. The vertical earth pressure at the top of culvert shows a non-linear increase trend along with the increase of filling height, slope height. When the slope height and filling height is small, earth pressure value increases with the increase of gradient. When the slope height and height of filling is large, soil pressure value decreases with the increase of slope. (2) On rigid foundation, it is analyzed that the coefficient of the vertical earth pressure located on the culvert section under pavement vary along with the slope height and gradient. The vertical earth pressure on culvert at the mid-line of road changes with the slope height. The results show that the vertical earth pressure on culvert at the mid-line of road nonlinearly increases with the increase of the slope height. The fitting earth pressure formula is quadratic polynomial.(3) On the soft foundation, taking box culvert as the research object,it is analyzed that distribution rule of soil pressure on culvert changes along with the different gradient and filling height.(4) The numerical simulation of the construction process of culvert is also called layered filling process. Comparing the numerical calculation of one-time fill, it is analysed that the displacement tendency of the filled soil changes under culvert structure and soil interaction.(5) The theoretical formula of culvert system under slope is studied. Combining theoretical derivation with quadratic polynomial which is come from fitting curve, it is compared and analyzed in order to get nonlinear formula of the vertical earth pressure on culvert under embankment.It is convenient for engineering reference. |
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