Investigating the influence of the diameter of a fiberglass pipe on the deformed state of railroad transportation structure "embankment-pipe"

Abstract

This paper has analyzed the use of fiberglass pipes in the body of the railroad embankment by a method of pushing them through the subgrade. A flat rod model has been improved for assessing the deformed state of the transport structure "embankment-fiberglass pipe" by a method of forces when replacing the cross-section of the pipe with a polygonal one. The analytical model accounts for the interaction between the pipe and soil of the railroad embankment. To this end, radial and tangential elastic ligaments are introduced into the estimation scheme, which make it possible to simulate elastic soil pressure, as well as friction forces that occur when the soil comes into contact with the pipe. The deformed state of the transport structure "embankment-fiberglass pipe" was calculated by the method of forces and by a finite-element method under the action of load from the railroad rolling stock, taking into consideration the different cross-sections of the pipe. It has been established that with an increase in the diameter of the fiberglass pipe, the value of deformations of the subgrade and fiberglass pipe increases. With a pipe diameter of 1.0 m, the deformation value in the vaulted pipe is 2.12 mm, and with a pipe diameter of 3.6 m – 4.16 mm. At the same time, the value of deformations of the subgrade under the sleeper is 5.2 mm and 6.0 mm, respectively. It was determined that the maximum deformations of the subgrade, which occur above the pipe, with a pipe diameter of 3.6 m, are 4.46 mm. At the same time, the maximum vertical deformations of a fiberglass pipe arise in the pipe vault and, with a pipe diameter of 3.6 m, are 4.16 mm. It has been established that the maximum horizontal deformations of the subgrade occur at points of horizontal diameter of the fiberglass pipe while the minimal horizontal deformations of the subgrade occur at points lying on the vertical diameter of the pipe