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2020

Science and Technology Studies

Laboratory

Articles 1 - 3 of 3

Full-Text Articles in Engineering

Performance Of Ballast Influenced By Deformation And Degradation: Laboratory Testing And Numerical Modeling, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn Jan 2020

Performance Of Ballast Influenced By Deformation And Degradation: Laboratory Testing And Numerical Modeling, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part B

This paper presents a study on the deformation and degradation responses of railway ballast using large-scale laboratory testing and computational modeling approaches. A series of large-scale triaxial tests were carried out to investigate the ballast breakage responses under cyclic train loading subjected to varying frequencies, f=10-40  Hz. The role of recycled rubber energy-absorbing mats (REAMs) on reducing ballast breakage was also examined. Laboratory test results show that the ballast experiences significant degradation (breakage) and deformation, while the inclusion of REAMs can reduce the ballast breakage up to about 35%. Numerical modeling using the coupled discrete-continuum approach [coupled discrete-element method-finite-difference method …


Biodegradable Prefabricated Vertical Drains: From Laboratory To Field Studies, Thanh Trung Nguyen, Buddhima Indraratna, Pankaj Baral Jan 2020

Biodegradable Prefabricated Vertical Drains: From Laboratory To Field Studies, Thanh Trung Nguyen, Buddhima Indraratna, Pankaj Baral

Faculty of Engineering and Information Sciences - Papers: Part B

Biodegradable prefabricated vertical drains (BPVDs) made from natural fibres have been in use for several decades to improve soft soil, especially in East and Southeast Asia despite the fact that this type of drain has still not been fully addressed and evaluated. This study presents a series of laboratory tests where a drain made from coconut cores wrapped in Indian jute sheath filters is compared to conventional synthetic prefabricated vertical drains (SPVDs). Discharge volume tests are carried out with and without soil clogging to understand how jute drains can resist soil clogging under increasing confining pressure. Along with these macro-hydraulic …


A Laboratory Study On Fluidization Of Subgrade Under Cyclic Train Loading, Buddhima Indraratna, Mandeep Singh, Thanh Trung Nguyen, Serge Leroueil, Aruni Lakmali Abeywickrama Bamunusing Kankanamge, Richard B. Kelly, Tim Neville Jan 2020

A Laboratory Study On Fluidization Of Subgrade Under Cyclic Train Loading, Buddhima Indraratna, Mandeep Singh, Thanh Trung Nguyen, Serge Leroueil, Aruni Lakmali Abeywickrama Bamunusing Kankanamge, Richard B. Kelly, Tim Neville

Faculty of Engineering and Information Sciences - Papers: Part B

A long term issue that has hampered the efficient operation of heavy haul tracks is the migration of fluidized fines from the shallow soft subgrade to the overlying ballast, i.e., mud pumping. This paper presents a series of undrained cyclic triaxial tests, where realistic cyclic loading conditions were simulated at low confining pressure that is typical of shallow subgrade beneath a ballast track. Subgrade soil specimens with a low plasticity index collected from a field site with recent history of mud pumping were tested at frequencies from 1.0 to 5.0 Hz and a cyclic stress ratio (CSR) from 0.1 to …