Characterisation of Geogrid and Waste Tyres as Reinforcement Materials in Railway Track Beds.

Lihua Li,Na Chen,Yanan Fang,Mi Tian,Bowen Cheng,Yiming Liu

doi:10.3390/ma14154162

Abstract

The engineering behaviour of ballast is an important factor to determine the stability and safety of railway tracks. This paper examines the stress–strain, shear strength, peak deflection stress and reinforcement strength ratio of different reinforcement materials and reinforcement locations in ballast track bed layers based on large scale static triaxial shear tests. The results show that geogrid and waste tyre reinforcement have a significant effect on the peak deviator stress of railway track bed layers and the stress–strain relationship is strain-hardened. The peak deviator stress and shear strength of geogrid reinforcement are greater under the same conditions compared with waste tyres. The reinforcement of geogrid and waste tires increases the shear strength of the track bed significantly. The more layers of geogrid reinforcement, the more energy is required for the deformation of the track bed. The energy required for deformation is greater in the centre of the waste tyre than in the other reinforced forms, and the energy required for deformation is minimal in the fully reinforced form. Excessive tyre reinforcement changes the stiffness of the track bed layer, leading to an increase in the settlement rate. The reinforcement strength ratio between geogrid and waste tyre increases significantly with the increasing of the confining pressure and reinforcement layers. Moreover, the reinforcement strength ratio of the geogrid is significantly higher than that of the waste tyre.

Highlights

The ballast railway track bed structure is composed of a ballast layer and a sub-ballast layer, which is filled with ballast particles of different grain sizes
Indraratna et al [26] studied rubber tiremixtures were used as the foundation and structural interface, which reduced ground acreinforced ballast layers in triaxial tests, and the results showed that rubber tire reinforced celeration by 60–70% in both vertical and horizontal directions
Indraratna et al [26] studballast layers can reduce ballast degradation and the particle movement of the track ied rubber tire-reinforced ballast layers in triaxial tests, and the results showed that rubber substructure

Summary

Introduction

The ballast railway track bed structure is composed of a ballast layer and a sub-ballast layer, which is filled with ballast particles of different grain sizes. The track bed layer is based primarily on the interlocking of ballast aggregate particles to distribute the wheel loads to the top of the track bed, or to the subgrade beneath it, to an acceptable level. Excessive load of the running train will cause the vertical and lateral displacement of the railway track bed, which will eventually lead to excessive settlement and instability of the track bed. The railway department must take effective measures to solve the above problems, which may cause a series of safety problems such as train derailment and track misalignment

Methods

Results

Conclusion