Force and Deformation of a Shallow Soil-Buried Super-Long Box Culvert during Jacking Construction on a Highway

Abstract

An example of a project on an oversized box culvert jacked into highway subgrade in Guangdong area was investigated to determine the mechanical behavior of shallow soil-covered super-long box culvert in the jacking construction process. On the basis of 3D finite element simulation, the law for stress–strain change and the effective construction area of the box were studied by considering different lengths and thicknesses and drag reduction versus non-drag reduction of overburden soil. Result shows that under the same working condition, the stress–strain of the roof and bottom plate exhibits an “armchair” change shape with an increase in jacking length, whereas the side wall presents a “trapezoid” shape in the box culvert jacking process. The thickness and characteristics of the covered soil (on top of the box culvert) exert considerable influences on the stress–strain of the box culvert structure. If the covered soil is thick and dense, then the stress–strain of the structure will be high. The pavement (on top of the box culvert) settlement ranges from 7.–17.1 mm due to the effect of vibrations produced during box culvert jacking construction, and the scope of the disturbed roadbed and road surface is 23–3 m along the jacking direction. The drag reduction effect of the paraffin oil mixture is more effective than that of slurry drag reduction. The research results will play a significant guiding role in the design and construction of similar projects.