Experimental investigation and numerical simulation of nonlinear earth pressure for trench-buried culverts

The variation of vertical earth pressure on trench-buried culverts was not accurately reflected by the linear earth pressure theory in the prevailing Chinese General Code for Design of Highway Bridges and Culverts.The calculated results using the code method were different from the practical situations,which might induce various problems in the construction process or in service time of culverts.So the variation of vertical earth pressure and soil arching effect in fill for culverts installation were studied based on the field experiments and FEM numerical simulation.Meanwhile,the distribution of earth pressure and differential settlement at the elevation of culverts top were analyzed.It was shown that the vertical earth pressure on the top of trench-buried culverts was not always less than the calculated result of the linear earth pressure theory,and it increased nonlinearly with the influential factors,such as the height of embankment fill,the width of trenches,the slope angle of trenches,the geometric size of culverts,the characteristics of fill and the elastic modulus of ground.When the fill on the culvert reached a certain height,soil arch was generated.The soil arching effect could release the stress concentration on the top of culverts,but it is instable.The influence of these factors on the stresses of trench-buried culverts should be comprehensively considered in the design and construction procedure.