Modelling and Analysis of Rails on Viscoelastic Foundation Under a Moving Load

The proposed analysis predicts the time-dependent behaviour of rails resting on geocell-improved soft clay subgrade subjected to moving load. Rail and geocell (with infill soil) have been modelled as Euler-Bernoulli beams of infinite length with finite bending stiffness. Upper granular mat has been characterized as Pasternak shear layer sandwiched between two beams resting over soft clay subgrade idealized by the four-parameter Burger model. Developed governing differential equations have been non-dimensionalised using appropriate dimensionless parameters. Numerical solution of these equations has been obtained by a finite difference scheme in conjunction with the Gauss-Seidel method in an iterative manner using appropriate boundary conditions. Detailed parametric study has been conducted to understand the influence of Burger model parameters, velocity and magnitude of applied load, flexural rigidity and location of geocell on the flexural response of rails. Critical velocity has been determined, and its time dependency has also been discussed. The present study also reports variation in degree of consolidation with elapsed time and procedure to obtain consolidation characteristics for such a double beam system representing geocell-reinforced railway tracks.