Influence of moisture content on the dynamic properties of an interlayer soil under cyclic loading

Abstract

The ‘Interlayer’ soil (ITL) of the French conventional railways platforms, a coarse grain soil with low permeability, was studied. Two samples of ‘interlayer’ soil were tested in a large scale triaxial cell (ø= 300 mm) at different hydric conditions: w = 4% (OPM) and w = 10% (Saturated). In each test, 5 different cyclic loading levels (from ∆q = 10 kPa to ∆q = 30 kPa per cycle) and 3 simulated train speeds (100, 160 and 200 km/h) were considered. The loading levels simulate the real amplitude loading that arrives to the ITL depth in a real railway platform. The results show the influences of the loading frequency and amplitude on the ITL soils' cyclic behavior. In this paper, is presented the evolution of the elastic modulus and damping ratio forthe considered loadings under different hydric conditions. When loading amplitude is increased, the elastic modulus and damping ratio decrease. Furthermore, the influence of loading frequency is found to be negligible for the elastic modulus whereas is more notorious on the evolution of damping ratio when soil is saturated.