Abstract: In order to explore the influence of cumulative deformation from the constructing shallow buried glass fiber reinforced plastics mortar (FRPM) pipe culverts on the carrying capacity during the service period, a numerical calculation model of pipe-soil interaction for flexible FRPM culvert was established based on the field load test of the culvert in the subgrade filling constructing period. The effects of three different filling heights and three kinds of deformation rate on mechanical parameters such as circumferential strain, von Mises stress and earth pressure around pipe were studied through simulation. The results illustrate that the culvert has irregular ellipticity with the increase of the culvert deformation rate. Its stress mode changes from the circumferential overall uniform force to the more concentrating load on the upper part especially in the top area of the culvert. At the equivalent filling height, the circumferential strain, von Mises stress and earth pressure around pipe increase significantly with the increase of the deformation rate, and the greater the deformation rate, the more severe the adverse effect on the long-term mechanical properties of the pipe culvert. Meanwhile, increasing the thickness of the fill reduces the burden on the culvert. During the constructing period, the culvert deformation rate can be significantly reduced by setting steel support device inside the culvert, which contributes to improving the stress bearing mode and durability of culverts in the course of the service period.

Key words: FRPM pipe culvert, deformation rate, constructing period, pipe-soil interaction model, mechanical property, composites