Study On Earth Pressure And Ground Bearing Capacity Of High Embankment Culvert

Culvert is indispensable to highway construction of drainage and transportation facilities, how to consider culvert embedding method, site conditions and structure all have influence the culvert stress characteristics. Differential settlement in the plane of the culvert top decide the culvert top earth pressure concentration, and the culvert on the rigid foundation earth pressure concentration of problems. On soft soil crust layer, If full use of the carrying capacity of the mantle layer explored, the pressure on crown of culvert and the culvert stress concentration can be optimized, and the construction cost can be reduced significantly. Based on this, this article research and the foundation bearing capacity through the theoretical analysis and numerical simulation of high fill culverts on soft soil ground soil pressure system, the main contents are as follows:First of all, based on the culvert weeks filling displacement law, using the theory of elasticity formula principle of foundation settlement, this thesis derives the theoretical formula used to calculate the culverts "neutral position". And in this thesis, the formula of "neutral position" compares with the results of numerical simulation analysis, studied the culvert top filling height, stiffness, sizes of culvert and the foundation soil stiffness parameters such as the impact on the culverts "neutral position". The results show that under different parameter condition, using the theoretical method in this thesis and numerical simulation method of culvert "neutral position" change rule basically the same. The two kinds of methods to calculate the "neutral position" with filling height, stiffness, increasing the height of culvert and the foundation soil stiffness, the nonlinear increasing trend; And decreases with increasing of the width of the culvert.And then, through has been culvert "neutral position", it is deduced that soil stress calculation formula of the top and he bottom of the culvert in soft soil area, and the results will be compared the formula and modified Marston formula method, soil column method, pressure coefficient method, M.M. promojiyfakonov unloading arch method, Gu Anquan formula method and finite element method calculation, this thesis derives the theoretical formula method and finite element method, and analyzes the influence law of the culvert top filling height, stiffness, size of culvert and the foundation soil stiffness parameters to the culvert top and culvert subsoil pressure. Results show that the seven methods, as the change of different parameters, only in this thesis, theoretical formula calculation value and the numerical simulation is close to and change rule is more consistent.Finally,based on the characteristics of the culvert sides fill load, and based on the limit equilibrium theory of Meyerhof & Hanna, based on the ultimate bearing capacity formula is deduced for calculation of culvert with mantle layer calculated formula of ultimate bearing capacity of foundation. Hansen weighted average method, the stress diffusion angle method, Improved formula method proposed in this thesis and finite element method of the calculation results are compared, the height of embankment fill, shell thickness, shell layer and under the soft soil cohesion and internal friction Angle ratio on the ultimate bearing are studied, and the calculation results of the four methods are compared with the engineering examples. The results shows that: with the height of embankment fill and the increase of shell thickness, improved formula method and finite element method to calculate the results of the foundation bearing capacity is most close. The change of cohesion and internal friction Angle than to improve the formula method and finite element method of the calculation results are consistent. Improve the formula calculation results than Hansen weighted method and the stress diffusion angle method is more close to the engineering example.