Article
Transportation Science & Technology
Haydn Hunt, Buddhima Indraratna, Yujie Qi
Summary: This study evaluates the ductility and energy absorbing capacity of coal wash-rubber crumb mixtures subjected to triaxial shearing. The results show that the addition of rubber crumb improves the ductility and energy absorbing capacity of the waste mixture, making it a promising development for future rail design. Empirical models for the shear strength and strain energy density based on the rubber crumb content are proposed to approximate the properties of these mixtures before extensive testing.
INTERNATIONAL JOURNAL OF RAIL TRANSPORTATION
(2023)
Article
Construction & Building Technology
Miriam Tawk, Yujie Qi, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Ana Heitor
Summary: This study investigates a potential composite of coal wash and rubber crumbs as a capping material for railways, with a series of cyclic triaxial tests providing insight into the deformation mechanism of rubber particles. The inclusion of rubber crumbs is found to increase axial permanent strain and volumetric strain, while decreasing resilient and shear modulus. Moreover, the mixture with rubber crumbs shows improved energy dissipation efficiency after rest periods, reducing the breakage index even with increased load cycles.
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
(2021)
Article
Multidisciplinary Sciences
Beifang Wang, Duo Zhou, Jing Zhang, Bing Liang
Summary: In this study, the spontaneous combustion problem of coal relics caused by the overburden fracture network was investigated. Physical similar simulation tests were conducted using the 31114 working face of Lijiahao coal mine as the research background. Fractal dimension and image processing techniques were used to analyze the characteristics of overburden transport and fracture development. The results revealed that stress changes in the upper and lower rock seams during key seam fracture and the fractal dimension and area of fissures changed accordingly. Moreover, the mechanical models of solid support beam and masonry beam were used to analyze the reasons behind fracture dynamic evolution.
SCIENTIFIC REPORTS
(2023)
Article
Engineering, Geological
Yujie Qi, Buddhima Indraratna
Summary: Many studies have focused on the effect of rubber crumbs content on damping ratio, shear modulus, and total deformation in rubber crumbs-soil/waste mixtures; however, research on the influence of rubber crumbs content on the permanent strain rate and deformation mechanism under repeated loading is limited. This study analyzes the cyclic deformation response of mixtures containing steel furnace slag, coal wash, and rubber crumbs and finds that rubber crumbs content significantly affects the initial permanent strain rate and the slope of the permanent axial strain rate line, while cyclic deviator stress mainly affects the initial permanent strain rate. An empirical model is developed to predict the permanent deformation mechanism of the mixtures with varying amounts of rubber crumbs and higher cyclic deviator stresses.
Article
Green & Sustainable Science & Technology
Gang Xu, Tingting Ma, Chaofeng Wang, Hongwei Jin, Yunlong Wang
Summary: The prediction and prevention of mine disasters are crucial for identifying the stress and strain state of coal using ultrasonic response characteristics. This study conducted ultrasonic testing experiments on coal samples under uniaxial loading and focused on analyzing the relationship between the stress-strain state of coal samples and the ultrasonic velocity and quality factor. The results demonstrated significant differences in ultrasonic response characteristics of coal under various stress and strain states.
Article
Engineering, Civil
Yangping Yao, Kui Zhang
Summary: This paper discusses a fundamental issue in geotechnical engineering, deformation calculation, and proposes a new concept of stress-strain chain for the analysis of the computational process of plastic strain. The inadequacies of previous research on plastic strain computation are evaluated using the stress-strain chain. The innovations of the UH model and their enhancement of deformation calculations are also introduced.
TRANSPORTATION GEOTECHNICS
(2022)
Article
Geochemistry & Geophysics
Yan Chen, Gaofei Wang, Lei Zhou, Guolong Zhang, Jiangfan Yang, Meiheng Li
Summary: This study investigates the effect of cyclic loading and unloading on the deformation and damage characteristics of sandstone underneath the Bohai Sea. The results show that under cyclic loading and unloading compression, the stress-strain curves of sandstone form a hysteresis loop. The deformation and damage parameters of sandstone exhibit different trends with the change of cycle number and unloading stress level.
Review
Energy & Fuels
Qi Gao, Jishan Liu, Yifan Huang, Wai Li, Rui Shi, Yee-Kwong Leong, Derek Elsworth
Summary: The evolution of coal permeability is complex and has led to the development of numerous models. Despite efforts to evaluate these models, the reasons for discrepancies between observations and predictions have not been identified. This study examines the models and concludes that they can be categorized into equilibrium and non-equilibrium models based on the internal structure of coal, boundary conditions, and equilibrium state. It is found that the exclusion of equilibration process is the root cause of discrepancies and suggests future research should integrate rock structure, boundary conditions, and equilibration process in coal permeability models.
Editorial Material
Engineering, Ocean
Abdellah Cherif Taiba, Youcef Mahmoudi, Mostefa Belkhatir
Summary: The purpose of this paper is to provide a detailed summary of the published paper titled "Stress-strain behavior of marine calcareous soil-tire mixtures" in the journal of Marine Georesources and Geotechnology. The aim of this article is to enhance the content's coherence and present it as a discussion paper by Shariatmadari et al. (2022).
MARINE GEORESOURCES & GEOTECHNOLOGY
(2023)
Article
Engineering, Geological
Ching S. Chang, Yibing Deng
Summary: The energy equation, based on the first law of thermodynamics, includes the dissipation energy and Helmholtz free energy of a system. Current stress-dilatancy relationships often overlook the role of Helmholtz free energy, but recent observations suggest the importance of including it in order to accurately model stress-dilatancy behavior. Additional terms in the energy equation are necessary to address this issue.
Article
Mechanics
Yugui Cao, Longlong Li, Muyu Liu, Yufei Wu
Summary: The study found that under CFRP confinement, the compressive strength and ultimate strain of rubber concrete decrease with increasing rubber volume replacement ratio, while the stiffness of confinement also decreases with increasing rubber content.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Geological
P. K. Triantafyllos, V. N. Georgiannou, Y. F. Dafalias, I. -O. Georgopoulos
Summary: Sand exhibits weak or strong non-coaxiality under different loading conditions, influenced by stress and shear direction. As the stress ratio increases, sand ultimately reaches a steady state, showing distinct non-coaxiality patterns.
Article
Chemistry, Physical
Dazi Li, Jianxun Liu, Zhiyu Zhang, Mingjie Yan, Yining Dong, Jun Liu
Summary: In this paper, a F-LSTM neural network prediction model is proposed to quickly obtain the tensile stress values under experimental strain rate. The experiment results show that the model can effectively extrapolate the results of MD simulations. The introduction of fractional calculus improves the prediction accuracy of the LSTM model.
MOLECULAR SIMULATION
(2022)
Article
Chemistry, Physical
Zenon Szypcio, Katarzyna Dolzyk-Szypcio
Summary: This study analyzed the results of triaxial compression tests on naturally and artificially bonded soils from the literature. It was found that there are three characteristic stages of plastic flow during shear. The stress-dilatancy behavior in all stages can be approximated by the general linear stress-dilatancy equation of the Frictional State Concept. The failure states and newly defined dilatant failure states are not the same for many shear tests. The points representing dilatant failure states form a straight line, with its position and slope depending on the soil type and amount of cement admixture.
Article
Engineering, Geological
A. Lashkari, S. R. Falsafizadeh, Md M. Rahman
Summary: This paper investigates the impact of volume change boundary conditions on the instability and post-peak softening of sand, revealing that volumetric expansion intensifies instability susceptibility while volumetric contraction reduces vulnerability. Experimental data analysis using Hill's second-order work criterion predicts relational trends for instability lines, normalized peak shear strengths, and maximum pore-water pressure ratios depending on the coupling between volumetric and shear strain rates. A simple state-dependent constitutive model is found to accurately predict relational trends in sand specimens experiencing instability and post-peak softening under different degrees of linear coupling between volumetric and shear strains.
Article
Engineering, Geological
Buddhima Indraratna, Subhani Kanchanamala Medawela, Senura Athuraliya, Ana Heitor, Pankaj Baral
Summary: The generation of acidic groundwater from pyrite oxidation in low-lying acid sulfate soil has caused significant damage to the soil-water environment and infrastructure in coastal Australia. This study focuses on using limestone aggregates as the primary reactive material in permeable reactive barriers (PRBs) to neutralize acid and remove heavy metal contaminants. The laboratory experiments showed that limestone had a significant capacity for removing contaminants. However, the formation of secondary mineral precipitates within the PRB's granular media caused clogging and reduced the reactivity rate, particularly at the entrance zone.
ENVIRONMENTAL GEOTECHNICS
(2022)
Review
Green & Sustainable Science & Technology
A. S. M. Riyad, Fernanda Bessa Ferreira, Buddhima Indraratna, Trung Ngo
Summary: This study investigates the state-of-the-art literature on numerical modeling methods for assessing the performance of pile-supported rail embankments subjected to cyclic loading, highlighting the main results from various numerical methods in explaining load deformation response mechanisms. It also identifies key issues and drawbacks of these numerical methods in rail embankment development while outlining specific shortcomings and research gaps relevant to enhanced future design and analysis.
Article
Construction & Building Technology
Miriam Tawk, Yujie Qi, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Ana Heitor
Summary: This study investigates a potential composite of coal wash and rubber crumbs as a capping material for railways, with a series of cyclic triaxial tests providing insight into the deformation mechanism of rubber particles. The inclusion of rubber crumbs is found to increase axial permanent strain and volumetric strain, while decreasing resilient and shear modulus. Moreover, the mixture with rubber crumbs shows improved energy dissipation efficiency after rest periods, reducing the breakage index even with increased load cycles.
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
(2021)
Article
Engineering, Geological
Chathuri M. K. Arachchige, Buddhima Indraratna, Yujie Qi, Jayan S. Vinod, Cholachat Rujikiatkamjorn
Summary: This study focuses on the concept of using rubber granules from waste tyres as elastic aggregates blended with traditional ballast particles to improve the performance of rail tracks, forming a Rubber Intermixed Ballast System (RIBS). The research indicates that RIBS with over 10% rubber content consistently reduce dilation under changing confining pressures and effectively control ballast fouling within the granular matrix. The results also show that rubber particles ranging from 9.5 to 19 mm with similar angularity to ballast aggregates are advantageous in reducing the breakage of load-bearing larger aggregates.
Article
Engineering, Geological
Isabella Novais Silva, Buddhima Indraratna, Thanh Trung Nguyen, Cholachat Rujikiatkamjorn
Summary: This study investigates the influence of stress anisotropy and plasticity index on the shear behavior of soils and proposes empirical equations to estimate undrained shear strength.
Article
Engineering, Geological
Buddhima Indraratna, Yujie Qi, Miriam Tawk, Ana Heitor, Cholachat Rujikiatkamjorn, Sinniah K. Navaratnarajah
Summary: This paper presents recent research conducted at the University of Wollongong, Australia, focusing on the use of waste materials for transport infrastructure and the results of laboratory and field tests.
PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-GROUND IMPROVEMENT
(2022)
Article
Engineering, Geological
Rakesh Sai Malisetty, Buddhima Indraratna, Yujie Qi, Cholachat Rujikiatkamjorn
Summary: Understanding and quantifying the long-term deformation behaviour of granular materials under repeated loads is crucial for railway track longevity. Past research has investigated the shakedown response of rubber-granular waste mixtures, but a clear methodology for estimating shakedown yield limits has not been discussed. This study proposes a unified method of estimating the shakedown limit by analyzing permanent axial strains and normalized cyclic stress ratios.
Article
Engineering, Geological
Yujie Qi, Buddhima Indraratna
Summary: Many studies have focused on the effect of rubber crumbs content on damping ratio, shear modulus, and total deformation in rubber crumbs-soil/waste mixtures; however, research on the influence of rubber crumbs content on the permanent strain rate and deformation mechanism under repeated loading is limited. This study analyzes the cyclic deformation response of mixtures containing steel furnace slag, coal wash, and rubber crumbs and finds that rubber crumbs content significantly affects the initial permanent strain rate and the slope of the permanent axial strain rate line, while cyclic deviator stress mainly affects the initial permanent strain rate. An empirical model is developed to predict the permanent deformation mechanism of the mixtures with varying amounts of rubber crumbs and higher cyclic deviator stresses.
Article
Engineering, Geological
Subhani Medawela, Buddhima Indraratna, R. Kerry Rowe
Summary: This study demonstrates that the porosity of a permeable reactive barrier (PRB) material decreases significantly due to bio-geochemical clogging caused by acidic flow. Laboratory tests over 9 months show that chemical clogging accounts for 57% of the reduction in porosity, while biological clogging accounts for the rest. The proposed mathematical approach estimates that calcite dissolution and bio-geochemical clogging can reduce the surface area of limestone aggregates by over 70%.
CANADIAN GEOTECHNICAL JOURNAL
(2023)
Article
Engineering, Geological
Bin-Hua Xu, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Thanh T. Nguyen, Ning He
Summary: This study introduces a novel approach using the spectral method to analyze the nonlinear consolidation behavior of multilayered soil associated with coupled vertical-radial drainage. By incorporating time- and depth-dependent stress and soil properties into the model, the proposed method shows greater accuracy in predicting in-situ soil behavior. The parametric study indicates that the ratio between the compression and permeability indices has a significant impact on the consolidation rate.
Article
Engineering, Geological
Warantorn Korkitsuntornsan, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Thanh T. Nguyen
Summary: Previous studies have shown that shallow subgrade soil can transform into a slurry under unfavourable cyclic loading, but the depth-dependent behaviour of soil parameters during this process has not been properly understood. This study used a large-scale cylindrical test rig to observe soil behaviour along the depth of test specimens under cyclic loading, and quantified the onset of soil fluidization. The results showed that excess pore water pressure tends to rise more at the upper layers, causing zero-effective stress, while void ratio expands rapidly within the deteriorated soil fabric, making the water content approach the liquid limit of soil.
CANADIAN GEOTECHNICAL JOURNAL
(2023)
