Effect of Adjacent Axle Loads on Uplift of Rails on Geocell-Stone Column Improved Tensionless Foundation

Abstract

Rails resting over tensionless or unilateral foundation (responds to compressive forces only) has an uplift tendency ahead and behind the applied load. The presence of train of loads on such foundations may result in greater upward deflection of the rail. The current study investigates this possibility for rails on geocell-stone column improved tensionless foundations. Lumped parameter modelling approach has been used to idealize the rail on reinforced foundation. Granular layer has been placed between two infinite beams, one representing the rail and other the geocell with infill soil, and modelled as Pasternak shear layer. Stone columns and soft foundation soil beneath the beams have been idealized by Winkler springs of different stiffnesses. Mathematical model in the form of governing differential equations has been developed with due consideration to damping in the system. Finite difference method in combination with Gauss–Seidel iterative scheme has been used to arrive at their solution based on employed loading and the boundary conditions. Effect of adjacent axle loads and inclusion of stone columns on the response of the rail has been investigated. Influence of variations in input parameters of soil-foundation system has been studied in detail and presented in the form of non-dimensional charts along with a sensitivity study.