Physical Model Test Investigation of Mechanical Properties of Double Pipe Culverts Subjected to Vertical Loading

Abstract

The performance of double-pipe culverts remains unclear due to insufficient research on double culverts. This study made use of polyvinyl chloride pipe to simulate culverts. The effect of culvert spacing and fill height on the mechanical properties of double-pipe culverts before and after expanded polystyrene (EPS) plate load reduction was investigated through a series of model tests, and the results were compared with those obtained from single-pipe culverts. It was found that the earth pressure at the top of the culvert was the smallest when the culvert spacing was 1D (where D is the diameter of the double-pipe culvert). When compared with the single-pipe culvert, the earth pressure at the top of the culvert was smaller than that of the single-pipe culverts; only when the culvert spacing was 1D, the earth pressure on the right side of the culvert was slightly larger than that of the single-pipe culvert. The earth pressure at the top of the culvert could be reduced by 20% before load reduction and by 42% after load reduction. The effect of fill height on earth pressure was small, but it could reduce the circumferential strain of the culvert pipe. With the widespread use of double-pipe culverts, the study of double-pipe culverts is crucial. However, the current research on double-pipe culverts is insufficient. In order to understand the mechanical characteristics of double-pipe culverts, this study simulated double-pipe culverts through model tests. The influence of culvert spacing and filling height on the mechanical properties of double-pipe culverts with EPS plate before and after load reduction was studied and compared with single-pipe culverts with the same drainage capacity. The results showed that the replacement of single-pipe culverts with double-pipe culverts can effectively reduce the earth pressure at the culvert top and lateral. The earth pressure at the top of the culvert will be reduced by 20% before and 42% after EPS load reduction. The earth pressure on the top of double-pipe culvert decreases with the decrease of culvert spacing, and the circumferential strain of the pipe culvert can be effectively reduced with the increase of filling height.