Innovation in ballasted railway tracks by stabilizing soft clay substructures with RRP additive

Document Type : Research Paper


1 Tehran university of science and research

2 Iran university of science and technology

3 School of Railway Engineering Iran University of Science and Technology (IUST)

4 گروه راه و ترابری، دانشکده مهندسی عمران هنر معماری، دانشگاه آزاد اسلامی، واحد علوم تحقیقات تهران، تهران، ایران.


By developing in freight and high-speed railways, maintenance of ballast becomes an important challenge. Although the constructing of ballasted railways is significantly lower than ballast less types, stabilizing and removing the ballast layer is an important research topic. In this study with the aim of removing part of ballast and replacing with stabilized clayey soil, the possibility of using as a new type of ballast less railway has been proposed. In this regard, the clayey soil prepared from the Urmia Railway Station was used to mix with different percentages of stabilizing chemical Royal Road Packer 2-3-5 (RRP) material. Samples were made and different tests such as Optimum Water Content, Compressive, Tensile strength and Shear were carried out. Results showed that adding 1.52×〖10〗^(-2) percent of RRP reduces the optimum water content by 31% and increase the Compressive, tensile strength and shear to 46, 20 and 67% respectively. In the second step, stabilized samples with different percentages of RRP were subjected to a uniaxial cyclic loading test to evaluate displacement-cycle number behavior under railway operating equivalent loading with 100000 cycles were investigated. As a result, the sample with 2.73×〖10〗^(-2) percent RRP had largest hardness and lowest settlement. In view of damping, the sample with 1.52×〖10〗^(-2) percent RRP had the best performance and caused a 28% reduction in settlement and 25% increase in damping. Generally in term of static and dynamic tests results and economic issue, the value of 1.52×〖10〗^(-2)has been selected as optimal percent of usable additive.