Effect of water content on long-term cyclic behaviour of railway platform materials

Abstract

The ‘Interlayer’ soil in the French conventional railways platforms, a coarse grain soil with low permeability, was studied at different hydric conditions: w = 4% (OPM) and w = 10% (Saturated) using a large-scale triaxial (ø= 300 mm) cell. For each test, 5 different cyclic loading levels has been considered (from ∆q = 10 kPa to ∆q = 30 kPa per cycle). The loading levels simulate the real loading at the interlayer depth in a real railway platform. The results clearly show the influence of the non-saturation on the evolution of elastic modulus and damping ratio. When the loading level is increased, the elastic modulus decreases and the damping ratio increases. The accumulation of plastic strains after 90000 cycles was also analyzed for both hydric conditions, showing that the initial moisture content and the elastic modulus greatly affect the accumulative strains.