高路堤下涵洞地基处理现场测试与数值模拟研究

Field test and numerical simulation of ground treatment for culverts under high embankments

山区高速公路高填方涵洞工程应用广泛,由于地基处理不当造成的涵洞病害屡见不鲜。结合现场实测成果和有限元数值模拟结果,分析了涵洞结构物的受力状态及地基受力、变形特性,讨论了地基刚度、不均匀沉降对涵洞受力的影响和埋深效应对地基承载力的影响。研究结果表明:涵洞基底与相同标高下涵洞外侧路基基底土压力相差不大,地基设计时可按二者相等考虑;地基刚度越大,涵洞顶部土压力越大,对涵洞结构物强度要求就越高,地基处理中应尽量避免使用刚性桩复合地基。根据研究结果,提出了高路堤下涵洞地基的设计方法。

High fill culverts have been widely used in expressway in mountain area and problems of culverts frequently take place because of improper ground treatment. Field test and FEM numerical simulation were carried out to investigate the stress state of the culvert and ground, as well as the deformation characteristics of the ground. The effect of stiffness and uneven settlement of ground on the stress state of culvert and embedded depth on the ground bearing capacity are discussed. The research results show that the pressure of subgrade of culvert is close to that of the roadbed at the same elevation, which can be regarded as equal pressure in design of foundation. The stiffer the ground is, the higher the vertical earth pressure on the top of culvert will be. So a higher strength of culvert is needed and the application of rigid pile in ground treatment of culvert under high embankment should be avoided. In addition, the design method for foundation of culverts under high embankment is proposed based on the research results.