高填路基盖板涵外界面受力状态形成机制研究

依据原位试验和数值模拟研究高填路基盖板涵外界面受力状态形成机制。结果表明:涵洞顶面压力大于上覆填土自重,呈非均匀分布形式,涵洞侧墙顶相对于顶板中部承受更大的压力,侧墙主要承担了来自两侧填土的附加压力;涵洞侧墙外水平压力远小于按土柱高度换算的静止土压力,涵洞地基的不均一地质条件导致涵洞单侧承受相对较大的水平力;涵土差异沉降导致涵洞体承担了大于上覆填土自重的压力,基底的不均匀沉降引起涵顶压力向一侧集中,侧墙外压力和基底压力非对称分布。实测涵顶压力约为填土自重应力的1.56~3.02倍,使用现行公路桥涵规范设计高填方盖板涵偏于危险。

Mechanism of stress characteristics on surface of slab-culverts under high embankments

The state and distribution of stress on the exterior surface of slab-culverts under high embankments are investigated through field monitoring and numerical simulation. The results show that the earth pressure on the top slab of culverts is larger than the self-weight of filling soils over it, and the pressure distribution is uneven. The earth pressure on the top of side wall of culverts is larger than that at the surface center of top slab because the side walls undertake the additional earth pressure caused by the neighboring filling soils. The measured lateral pressure on the side wall is much lower than the earth pressure at rest calculated from the height of filling soils, and the inhomogeneity of foundation leads to unequal lateral pressure on the sides of the culverts. The differential settlement between the culverts and the soils results in the additional earth pressure on the top slab which is larger than the weight of filling soils. The differential settlement of the culvert foundation causes the stress concentration to the top of one side wall of culverts and nonsymmetrical distribution of pressure on the side wall and base of culverts. The measured vertical earth pressure is about 1.56 to 3.02 times larger than the self-weight of the soils. Therefore, it is dangerous to use the existing highway standards to design slab culverts under high embankments.