基于填土位移模式的超高填方涵洞土压力理论及动力特性研究

Superhigh embankment culverts are widely used in the constructions of mountainous highways. The earth pressures are affected by numerous factors and the existing theories are unable to reveal the essential relationship between them and the crown earth pressures, it causes a great difference between the theoretical results and the experimental results, which often results in cracking and other diseases of high embankment culverts. Based on the consideration of a variety of influence factors, series of analyses will be carried out to investigate the displacement mode of the high embankment fill, the calculation theory of the earth pressures and the dynamic characteristics of the culvert in this project. The influence factors on the earth pressures of superhigh embankment culverts will be analyzed and classified by investigations, experiments and numerical simulations. The displacement modes of the embankment fill will be observed by the digital imaging technology and discrete element simulations. The calculation model of earth pressure will be constructed with the consideration of the displacement mode, and the expression of the earth pressures on the crown of culvert will be deduced by theoretical analysis, field tests will be employed to verify the proposed theoretical methods as well. The stress and the deformation characteristics of the superhigh embankment culvert under seismic load will be investigated by experiments and numerical simulations. This project aims at revealing the mechanism of the influence factors affecting on the earth pressure on the culvert, establishing the earth pressure calculation model with a variety of factors influencing the earth pressures, and obtaining the stress and deformation laws of the superhigh embankment culverts under seismic load. It can provide key theoretical basis for the construction of superhigh embankment culverts.

超高填方涵洞在山区高速公路建设中应用广泛，由于其受力影响因素众多，现有理论没有揭示各影响因素与涵顶土压力的内在联系，理论结果与实际差别较大，导致高填方涵洞经常出现开裂等病害。本项目在考虑影响超高填方涵洞土压力的多种因素的基础上，紧紧围绕涵顶填土的位移模式、土压力计算理论及涵洞动力特性等基础科学问题展开研究。通过调研、试验和数值模拟分析涵洞受力的多种影响因素，并根据影响程度将各因素分类；利用数字成像技术和离散元模拟确定填土的位移模式；通过理论分析，建立考虑填土位移模式的土压力计算模型，推导涵顶土压力理论表达式，并利用现场试验对理论方法进行验证。通过模型试验和数值模拟，对地震荷载作用下超高填方涵洞的内力及变形特性进行研究。本项目旨在揭示涵顶土压力影响因素的作用机理，建立能够反映多因素的土压力计算理论，获得地震荷载作用下超高填方涵洞的内力和变形规律，为超高填方涵洞建设提供关键理论基础。

超高填方涵洞在山区高速公路建设中应用广泛，其受力影响因素众多，现有理论没有揭示各影响因素与涵顶土压力的内在联系，理论结果与实际差别较大，导致高填方涵洞经常出现开裂等病害。本项目考虑影响超高填方涵洞土压力的多种因素，围绕涵顶填土的位移模式、土压力计算理论和涵洞动力特性等基础科学问题展开研究。通过调研、试验和数值模拟分析涵洞受力的多种影响因素，确定了各因素对涵洞受力影响的大小关系；利用有限元和离散元模拟确定了填土的位移模式；通过理论分析，建立了考虑填土位移模式的土压力计算模型，推导涵顶土压力理论表达式，并利用现场试验对涵体位移和土压力进行了研究。通过数值模拟，对地震荷载作用下超高填方涵洞的内力及变形特性进行了研究。本项目研究揭示了涵顶土压力影响因素的作用机理，建立了考虑填土位移模式的土压力计算理论，获得了地震荷载作用下超高填方涵洞的内力和变形规律，此外，推导了双层地基条件下涵洞地基承载力计算公式，为超高填方涵洞建设提供关键理论基础。