Engineering Commons^™

Application Of Fractional Calculus In Modelling Ballast Deformation Under Cyclic Loading, Yifei Sun, Buddhima Indraratna, John Philip Carter, Timothy R. Marchant, Sanjay Nimbalkar

Faculty of Engineering and Information Sciences - Papers: Part A

Most constitutive models can only simulate cumulative deformation after a limited number of cycles. However, railroad ballast usually experiences a large number of train passages that cause history-dependent long-term deformation. Fractional calculus is an efficient tool for modelling this phenomenon and therefore is incorporated into a constitutive model for predicting the cumulative deformation. The proposed model is further validated by comparing the model predictions with a series of corresponding experimental results. It is observed that the proposed model can realistically simulate the cumulative deformation of ballast from the onset of loading up to a large number of load cycles.

Micromechanics-Based Investigation Of Fouled Ballast Using Large-Scale Triaxial Tests And Discrete Element Modeling, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part A

Railway ballast comprises unbounded discrete grains that are often used to form a load-bearing platform for tracks. Ballast degradation as trains pass over the tracks and infiltration of external fines including slurried (pumped) fine subgrade soils are two of the main reasons for ballast fouling. Fouling causes tracks to settle and also reduces the load-bearing capacity, which is associated with a reduction in internal friction and increased lateral spreading of the ballast layer. This paper presents a study of mobilized friction angle, volumetric behavior, and associated evolutions of contact and fabric anisotropy of fouled ballast subjected to monotonic triaxial loading …

Use Of Synthetic Inclusions For Enhanced Behaviour Of Railway Ballast Under Impact Loading, Fernanda Bessa Ferreira, Buddhima Indraratna

Faculty of Engineering and Information Sciences - Papers: Part B

Ballasted rail tracks form one of the largest worldwide networks catering to passenger and freight transportation. However, track deterioration associated with severe dynamic wheel loads is inevitable over the years leading to high maintenance costs. Geosynthetics and energy-absorbing rubber mats have increasingly been applied in rail track foundations to improve track stability and reduce the life-cycle cost of the railway system. This paper presents the results of an experimental study carried out using a high-capacity drop-weight impact testing apparatus to investigate the deformation and degradation response of railway ballast under impact loading conditions. The effectiveness of the geogrid reinforcement in …

Evaluation Of Mechanical Parameters Of Contaminated Road Base And Railway Ballast, Prajwol Tamrakar

Open Access Theses & Dissertations

This Dissertation comprises two topics in the area of transportation geotechnics that focus on the evaluation of stiffness parameters of contaminated road base and railway ballast. The abstracts of these two studies are provided in the following two paragraphs.

The performance of a flexible pavement depends on the mechanical characteristics of its unbound granular base layer. The mechanical characteristics such as stiffness and deformation resistance depend on many factors such as the material gradation, fines content, moisture content, physical properties of coarse aggregate and more. The base materials are often contaminated by the excessive fines that is caused by improper …