上埋式盖板涵受力特性及影响因素研究

现行公路桥涵设计通用规范中的土压力计算方法不能准确反映上埋式盖板涵的实际受力状态。结合现场测试和有限元数值模拟方法，分析了上埋式盖板涵在路堤填土荷载作用下的变形规律和受力特性，讨论了填土高度、填土性质、涵洞几何尺寸及地基弹性模量等因素对结构变形和受力状态的影响。研究结果表明：在填土荷载作用下，涵洞顶板、底板和侧墙均产生弯曲卸载现象，涵洞顶板、底板垂直土压力以及侧墙的水平土压力呈非线性分布，其实际受力状态与规范方法计算的结果存在较大差异。随着填土高度的增加，涵洞顶板和底板跨中及侧墙7h/8附近（h为涵洞侧墙高度）受到的土压力增长较慢，而在其他位置处土压力增长迅速。上埋式盖板涵设计和施工应综合考虑各种因素对结构受力状态的影响。

Study of stress characteristics and its influencing factors of embankment installation slab-culverts

The actual stress state of embankment installation slab-culvert was not accurately reflected by the calculation method of earth pressure in the prevailing Chinese General Code for Design of Highway Bridges and Culverts. So the deformation laws and stress characteristics of embankment installation slab-culvert under fill-load were studied based on field test and FEM numerical simulation. Meanwhile, the key influencing factors, such as the height of embankment fill, the characteristics of fill, the dimensions of the culvert and the elastic modulus of the ground on the structure deformation and stress characteristics were also discussed. It is shown that the bending unloading effects of the top slab, the bottom slab and the lateral walls of the culvert were generated under the fill load, the distributions of vertical earth pressure on the top slab and the bottom slab, as well as the lateral earth pressure on the walls are all nonlinear, they are significantly different form the results calculated by the code method. With the increasing of the embankment fill, the earth pressures on the mid-span of the top slab and the bottom slab, as well as the position near 7h/8 (h is the height of the culvert wall) of the walls has a trend of slow increase; however, they are rapidly increased away from the above- mentioned position. The influence of the factors on the stress state of embankment installation slab-culverts should be comprehensively considered in the design and construction procedure.