| As highway construction in the mountainous area is more and more, in order to meet the demand of design of the alignment of road, there are more and more culverts in more than 20m high embankment. But because of the lack of reasonable calculation principle of earth pressure, there are many culvert suffered local structural damage and some other spent lavishly or wastefully on designing culverts.This paper has discussed in many detail many classical theory, find out their limitations and technical advantage. They are equilibrium arching theory, Marston limitting equilibrium theory, regulate soil column method, Yang nonlinear method of calculating earth pressure and Terzaghi theory.The Maston theory establishment in the foundation of"the friction theory", Calculate earth pressure at the top of culvert pipe in using the state of limit equilibrium about the non-uniform piles. Proposed that the supposition pipeline itself and its both sides earth unequal settlement causes the culvert not only receive the earth pressure and shearing force coming from the both sides soil layer. when plane of rupture reach plane of equal settlement in the settlement process, this earth press calculation is bigger than traditional calculation. traditional soil column method is calculation of the vertical earth pressure supposes that the earth pressure of the top of the culvert is deadweight of the soil column. This method is common method currently in designing of culvert.Equilibrium arch theory based on rock subway deformation supposes that soil is the non-uniform piles and there is a arch of the top of the culvert in the settlement process. The earth pressure up of arch affect the structure of the arch and the earth pressure inside of arch affect the top of the culvert. This method calculation is lower traditional soil column.Terzaghi theory is based on rock characteristics, supposing that soil is the non-uniform piles and pressure of the top of culvert caused by the stress transfer, discusses a body as the thin-layer element, in the thin layer settlement process the friction force passes on to both soil sides, so the calculation of this method is lower the traditional soil column method too.Yang non-linear stress calculation is based on the interior model test and numerical simulation, this method calculation is between the arch effect and Terzaghi theory. This theory of earth pressure calculation based on lab test results to the statistical analysis obtains the formula for calculating the results show that the soil has the nonlinear characteristics of stress. Since these theories have a wide variety of computing limitations, and these theories are based rock non-uniform piles assumption, and soil as a unique engineering material, it has unique structure and stress-strain characteristics, and loose soil and soil compaction is also obvious difference in characteristics. So applying these theories to calculate the soil of the earth pressure will inevitably be the result of distortion. The paper is based on experiment contrast the applicability of these theories and explore the true discipline of soil pressure.Finite element simulation method selectes accurate constitutive model of soil, sets the appropriate boundary conditions, a reasonable soil materials and finite element mesh unit approach, in order to set up the finite element solid model for finding out the true discipline of soil pressure.This paper has been selected the Drucker-Prager soil constitutive model and the calculation of the appropriate boundary conditions and the model loading test stratified. This paper calculates the soil pressure on top of culvert and side of it in ABAQUS software that the reinforced concrete culvert is 24m height of fill covered examples of simulated filling process of hierarchical top of the culvert to for finding out the changes of earth pressure. The results show that the culvert top soil pressure with a height of fill is the increase in non - linear changes and the delta of earth pressure continues to decrease. Soil stress changing in the top of culvert just like parabolic, and obtains a function in least square method to fitting the data, which is close to Yang non-linear stress calculation.Indoor and outdoor test results indicate the discipline of soil pressure of the top of culvert is nonlinearity , in the low fills the pressure is bigger than the norm and in the high fills the pressure is lower than the norm. the indoor test results indicates that structure of the culvert destroyed the discipline in the soil, that is to say stiffening effect of arch and concentration of stress. Fitting data of outdoor test results a curve function that is y = a lnx + bx. The collective answers to the above discourse can determine the result of the evaluation. This function is worth popularizing. In short, the many tunnels are in the rock environment, and the subway is more digged in the soil environment. Soil and rock there is a significant difference in comparison, structure effects of soil is more weak than the effect structure of rock. Therefore the application rock hypothetical theory in the soil is incomplete. High embankment soil changes the course of the original stress environment, and then rolled soil comes into new stress environment. In this paper, the results of research comes from this new environment, the general characteristics of the stress, that is, discipline of soil pressure is in the law of parabolic type.The impact factors of soil pressure are enormous such as diameter of particles of soil, water content, mineral composition, degree of compaction. However, in such of factors, the most influential factors are diameter of particles of soil and degree of compaction.Indoor and outdoor test results are different because of different the size of the selected components of the filling and compaction degrees. Indoor and outdoor soil pressure test data also demonstrated the results of finite element simulation is right, confirmed that discipline of soil pressure is nonlinearity. This is because there is a special body in soil that is a powerful macro-structure of the soil to support the upper part of the load, which effectively prevents the top soil load transferring. The results for study of soil macro-structure must have reference in the future.There are not only micro-structure and also macro-structure in soil, such as beds, cracks and so on. Embankment filling is a progress about rebuilding the structure of the destroyed soil from the original conversion to a new environmental stress. In this process it is built new structure of soil, which structure will grow more stable in the future.the data of test showed that the stress characteristics of soil and earth pressure is nonlinearity, not a simple changes such as traditional soil column method. It is important significance to study structure characteristics of soil structure for the development of underground space. It is effectiveness in contributing to the structural design of the underground and economy of use.
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