Prof. Ranjith Pathegama Gamage

Professor Ranjith Pathegama Gamage

Head of Geomechanics Engineering, Professor in Geomechanics Engineering
Department of Civil Engineering
Room 140, 23 College Walk (B60), Clayton Campus

Professor Ranjith from the Department of Civil Engineering has been awarded the ARC Future Fellowship (2009) for his research work to combat climate change.

Prof.Ranjith, P.G. joined the Monash university group in 2003. Before joining to Monash, he worked as an Assistant Professor in Geo technical and Rock Engineering at Nanyang Technological University, Singapore. His PhD was on the “Stress-strain and permeability characteristics of Two-phase (water+gas) flow through fractured rocks”.

Cracking one of the deepest of problems Professor Ranjith PG is among leading researchers trying to assemble hard numbers and facts that will make geo-sequestration possible. His explanation is that, If you try to force too much water down a small plughole, it ends up going everywhere.

Professor Ranjith Gamage has found the same principle holds true when pumping liquid carbon dioxide into rock deep underground. ‘After you inject for a certain period, say six months, then you have to stop for a period of time – a few months to a few years – because the carbon dioxide needs time to diffuse and equilibrate. Otherwise you risk cracking the rock due to the pressure build up.’ What he’s talking about has significant implications for geo-sequestration – preventing carbon dioxide from escaping into the atmosphere by storing it underground. This strategy has become a key topic of consideration for governments around the world as they prepare to cope with climate change.

Ranjith has become one of the leading researchers trying to assemble hard numbers and facts on what geo-sequestration would involve. The concept is simple: capture flue gas from a coal-fired power station or cement plant; liquefy it; transport it to a hole drilled one or two kilometres into the earth; and inject it into a coal seam or saline aquifer that can store it and hold it for thousands upon thousands of years. If only it were so easy, says Ranjith, who is an expert in the movement of fluids through rock. First, you have to ensure that the gas stays put. The low density of carbon dioxide means that it will always rise, putting pressure on the rock above – the cap or sealing rock – which must have very low permeability and must not crack. Then, there’s a question of economics. At a depth of one or two kilometres, each well costs between $20 and $50 million depending on the geological conditions. ‘You cannot drill an infinite number of holes. So how much can you inject down any one hole becomes an important question. And that’ where I’m focusing my work.’ Ranjith’s approach is a mix of experimental work and modelling. To assist, he has assembled the latest equipment into one of the most sophisticated testing facilities in the world.

He needs to work at pressures which are several hundred times higher than those close to the surface, with rock samples 20 times larger than most existing pressure chambers can handle, and in temperatures of around of 50 degrees Celsius. He began by looking at unminable coal seams, which can absorb carbon dioxide while displacing methane. Now, with the help of the Future Fellowship he is broadening that work to study saline aquifers in sandstone. ‘The fellowship has allowed me to work full-time on my research, which has accelerated my progress.’ It has also enhanced his ability to collaborate with colleagues.


  • Doctor of Philosophy (Ph.D.)


Shale Gas: Stimulation methodologies for enhancement of recoveries.
Stability of wellbore analysis.
Characterization of weathered rocks.
Tunneling in soft and hard ground.
Slope Stability of large deep, open cut mines.
Underground longwall mining.
Enhanced coal bed methane recovery, ECBM.
Hydro-fracturing and other simulation methods for depleted and tight reservoirs.
Two-phase and multiphase flow in fractured rock media.
Coupled Hydro-mechanical behaviour of fractured and porous rocks.
Gas outbursts and groundwater inundation in mines.
Research into Geosequestration of Carbon Dioxide (CO2), including geomechanical behaviour due to the stored supercritical CO2, Formation and swelling behaviour of rock media, Migration of CO2 due to change in insitu stresses.
Activation of faults due to the injection of high fluid pressures.
Rock physics under high pressure conditions.
Contaminant transport through rock.
Storage of chemical/nuclear waste in underground cavern.
Deep Geothermal works.

Professional Appointments:

2013 to Present: Professor, Dept. of Civil Engineering, Monash University, Australia.
2010 to 2014: ARC Future Fellow, Dept. of Civil Engineering, Monash University, Australia.
2010 to 2014: Associate Professor Dept. of Civil Engineering, Monash University, Australia.
2006 to Present: Senior Lecturer, Dept. of Civil Engineering, Monash University, Australia.
2003 to 2005: Lecturer, Dept. of Civil Engineering, Monash University, Australia.
2001 to 2003 : Assistant Professor, School of Civil and Environmental Eng., Nanyang Technological University, Singapore.
2000 to 2001: Research Fellow, Dept. of Civil Engineering, University of Wollongong, Australia.
1997 to 2000: PhD student, Dept. of Civil Engineering, Wollongong University.
1996 to 1997: Lecturer, Dept. of Civil Engineering, University of Moratuwa, Sri Lanka.

Professional Association:

Fellow Member, American Society of Civil Engineers, USA.
Fellow Member, Engineers Australia.
Member, American Rock Mechanics Association (Life Member), USA.
Member, American Society of Civil Engineers (Geo Institute).
Member, Society of Petroleum Engineering (USA).
Member of the American Geophysical Union , USA.
Member of International Society of Rock Mechanics, UK.
Member of Tunneling and Underground Construction Society of Singapore (2000-2003).
Working Group member – ITA (International Tunnelling Association).
Environmental Commission in Underground Activities- Represented Singapore (2002 to 2003).

Awards, honors and scholarships:

2017:  Excellence in Sustainability Research Award, Elsevier (Scopus)

2014: Vice Chancellors’ Award for the Excellence in Postgraduate Research Supervision.
2014: Dean’s Award for the best Postgraduate Research Supervision.
2013: Australian –China Group Mission Award, 2013(only one received to Monash University).
2012: Australian Leadership Awards 2012.
2011: Vice Chancellors’ Award for Excellence in Research – Early Career Researcher.
2011: Australia-China Fellowship Award.
2010: Australian Future Fellowship Award, ARC, Australia.
2010: Dean’s Award for Excellence in Research- Faculty of Engineering at Monash University.
2007: Australian Academy of Science Award.

Research Projects

Not started projects

Development of new technologies for deep coal-seam gas recovery.

Current projects

National Drop Weight Impact Testing Facility.

The seven Australian universities named in this proposal aim to develop a ‘national drop weight impact testing
facility’ for dynamic tests on geo- and construction materials and systems. This facility will provide state-of-the art
technology to observe the real time behaviour of elements and sub-assemblies under combined quasi-static and
impact loading. The large capacity and unique configuration of the facility make it feasible to carry out innovative
research in impact engineering. Applications include, but are not limited to, the structural safety of high impact risk
infrastructure including railway networks, tunnels and bridges, and also the development of cost-effective and
environmentally friendly building and construction materials.

An Advanced, Macro-scale, hydro-thermo-mechanical Testing Chamber for sustainable deep geological applications.

The deep Earth offers significant promise for enhanced sustainability, including novel options for resource
development and pollutant storage. A firm understanding of expected engineering behaviour is key to
successful ultilisation of the deep Earth. Engineers and geologists from nine leading Australian universities
are developing a new large-scale device capable of recreating ground conditions at depths up to 13km. The
Advanced Macro-scale Testing Chamber (AMTC) will be used to study hydro-thermo-mechanical aspects of
deep geological applications, including carbon dioxide storage, enhanced geothermal energy and
unconventional hydrocarbon reservoir development. The AMTC will also have capacity to study mechanisms
leading to earthquakes.

Geological sequestration of carbon dioxide in deep saline aquifers: coupled flow-mechanical considerations.

This project aims to evaluate the feasibility of large scale storage of carbon dioxide (CO2) in deep saline aquifers. Currently the ease with which CO2 can be pumped into these rock strata, and their storage capacity are uncertain because there is limited data on the effects of CO2 on the geo-mechanical properties of the rocks. Through performing experiments to quantify the physical and chemical changes that occur, a new model will be developed that can account for the interactions between the flow and mechanical response. This model will be used to study the response of reservoirs during CO2 sequestration and to provide guidance on optimum injection and storage strategies.

Multi-functional nano-modified cementitious materials for well cementing.

The integrity and longevity of well cement are paramount for the safe, efficient, environmentally sustainable
production of oil and natural gas resources. Cementing problems are the main factor contributing to incidents
during drilling and completion of wells. By incorporating different nano-materials in well cements, this project aims to develop multi-functional nano-modified cementitious materials with self-sensing properties and greater strength and durability under extreme conditions including high/low temperatures, high pressure and corrosive environments. It is expected that the novel cement developed will produce safer wells with fewer (gas) environmental emission risks, reducing the need for costly and wasteful remedial squeezes.The integrity and longevity of well cement are paramount for the safe, efficient, environmentally sustainable
production of oil and natural gas resources. Cementing problems are the main factor contributing to incidents
during drilling and completion of wells. By incorporating different nano-materials in well cements, this project aims to develop multi-functional nano-modified cementitious materials with self-sensing properties and greater strength and durability under extreme conditions including high/low temperatures, high pressure and corrosive environments. It is expected that the novel cement developed will produce safer wells with fewer (gas) environmental emission risks, reducing the need for costly and wasteful remedial squeezes.

Past projects

High precision ISSCO syringe pump.

Hot Dry Rock geothermal resources in Australia and India: opportunities for collaboration in the development of a new sustainable energy resource.

Long-term mechanical-flow performance of an enhanced geothermal reservoir.

Extraction of heat (geothermal energy) from deep earth is promising but inefficient so far. Heat is transferred when
huge quantities of water are pumped through; but recovery of heat is low and much water is lost. This Project
researches carbon dioxide (CO2) as an alternative to water. There are excellent prospects of relatively efficient
recovery. And any loss of CO2 as a working fluid in deep-earth geothermal reservoirs is beneficial: it is permanent
sequestration of carbon. The Project addresses fundamental questions on the evolution of fluid-flow systems,
recovery rate, long-term injectability, and mechanical-flow behaviour. Findings are expected to provide practical
information on the geomechanical viability of this green power option.

608517-TOPS in the Energy Call: FP7-ENGERY-2013-1.

Three dimensionally compressed and monitored Hopkinson bar.

Understanding material behavior under dynamic loading is essential in dealing with many engineering problems as excavation, fragmentation, earthquake, blasting, and structure design. In geo-technical and structure projects, materials are often subjected to existing confining stresses. The proposed 3 dimensional compressed and monitored Hopkinson bar allows determination of the dynamic mechanical properties and fracturing behavior of materials under such confinement. The full-field optical techniques with an ultra-high speed and resolution camera in the system will assist the quantitative measurement of deformation fields including small strain induced in brittle material’s failure and identification of constitutive parameters.

Australia-China Group Mission on the issue of Technology relating to Sustainable alternative Energy from the Deep Earth.

This group mission (GM) will seed collaboration between leading researchers in Australia and China, on the topic of fundamental and applied research on the use of the deep Earth for future energy sustainability. The GM will help facilitate working inter-institutional and inter-disciplinary relationships in the area of technical research on the development of: (1) new unconventional hydrocarbon energy resources; (2) underground coal gasification; (3) new geothermal energy resources, and (4) schemes for deep geological sequestration of carbon dioxide. Effective collaboration on the issue of deep Earth energy alternatives, between a coalition of leading Australian and Chinese researchers, will help build the research profiles of both countries in the area of energy technology and will provide new opportunities for export of ideas and technology. Australia and China’s early involvement in the development of creative energy solutions will help to secure the energy future of both countries.

Turning pile foundations into sources of renewable energy: addressing remaining geotechnical challenges.

Heat exchanger pile foundations are increasingly used to improve the energy efficiency of buildings and reduce their carbon footprint. However their geotechnical performance when subjected to heating and cooling processes is not well understood.
We aim to develop full understanding of the fundamental mechanisms controlling the thermo-mechanical behavior of heat exchanger piles using large scale field tests. The project will make a breakthrough in understanding the influence of temperature cycles on pile group behavior and shaft resistance. This will lead to improved design, greater confidence in heat exchanger pile systems by the engineering community and more reliable low carbon technology.

Hybrid Testing Facility for Structures under Extreme Loads.

The twelve Australian universities named in this proposal propose to develop a Hybrid Testing Facility (HTF)
for Structures under Extreme Loads. The LIEF proposal will facilitate the establishment of advanced testing
facility with access to the universities involved and to government and industry partners associated with
them. This next generation of structural testing will embrace hybrid testing in static, pseudo-dynamic and fast
modes and simulation of structures subjected to extreme loading events such as earthquakes, blast, impact,
fire, wind and ocean waves. Applications include structural safety of buildings, bridges, offshore structures,
mining structures and development of efficient renewable energy structures.

An assessment of carbon dioxide storage capacity of water bearing sedimentary basins.

Considerable urgency exists with respect to further developing the concept of CO2 storage in deep saline aquifers, which is the storage option with the largest capacity. However, one of the major uncertainties with this scheme is the poor knowledge of storage capacity assessment methods, coupled mechanical, flow and transport properties of such rocks under the influence of CO2. This project aims to reduce these uncertainties by experimental investigations of storage assessments of sandstone, the transport properties, and the effects this has on the mechanical properties. The data will be used to develop new storage models to investigate storage capacity of saline aquifers and identify suitable aquifers for large scale sequestration of CO2.

Improvement of the performance of water-sensitive geomaterials using hydrophobic additives.

Development of Leakage Resistant Well-Cements for Geo-Sequestration of Carbon Dioxide Application using Alkali Activated Slag and Geopolymer Cements.

Geo-sequestration is the most promising technology for disposing CO2 emissions. Currently, geo-sequestration uses Portland cement for sealing the wells after injecting the CO2 to underground reservoirs. The high pressure CO2-brine is acidic and is found to dissolve the Portland cement well-seals, and has been identified as one of the biggest risk factors of long term leakage of CO2. The project will study novel cements with superior acid resistance, containing no Portland cements. Leakage rates of all these cements will be studied in geo-sequestration simulating test facilities and numerical models will be developed for long term leakage rates. Leakage-proof well cements will be identified/developed for viable geo-sequestration technology.

Advanced Testing Facility for Geological Sequestration of Greenhouse Gases.

A facility for the analysis of geological materials and their geo-thermal-mechanical interactions with complex fluids (such as carbon dioxide CO2, water, methane) is required to support a large number of research projects in high priority areas including geological sequestration of greenhouse gases and oil/gas recovery at three different leading Universities. The unique features of the proposed facility are that it is capable of analysis large samples, under multiple forms of loading and over a range of high pressures and temperatures. This will enable us to do proper design, management, and optimization of subsurface CO2 sequestration operations for safe storage of CO2 in geological formations.

A laboratory investigation of the effects of gas adsorption on the fluid transport and geomechanical properties of coal with application to enhanced coalbed methane recovery and carbon dioxide sequest.

Investigation of permeability of fractured, steep and deep rock slopes with high groundwater pressures.

The investigation of influence of scale effects of strength failure modes of deep open cut slopes.

Investigation of strength deformability and failure mechanism of rock slopes in large open pit mines.

Hydro-mechanical interactions in coal geo-sequestration of carbon dioxide.

Geo-sequestration of carbon dioxide (CO2) is considered the most promising technology to reduce atmospheric release of CO2. The storage of CO2 in deep unmineable coal deposits has many advantages that include: a high storage capacity, high permeability, and the release of methane, a valuable resource. However, there is considerable uncertainty regarding the impact of CO2 on the mechanical properties of the coal. This project aims to reduce these uncertainties by experimental investigations of the transport of CO2 through coal, and the effects this has on the mechanical properties. The data will be used to develop new coupled numerical models that will be used to investigate the procedures required for successful sequestration.

Influence of scale effect on the strength of rock mass for the better prediction of slope stability in large open-cut mines.

The research project will concentrate primarily on understanding the mechanisms of slope failure in large and deep open cut mines with the goal of developing improved assessment criteria for designing rock slopes. Mechanisms governing shape, location and propagation of slope failure surfaces are highly dependent on insitu and induced stresses, strength of rock mass, and induced pore water pressure. Accurate determination of rock mass strength and their use in slope stability analysis will enable mining engineers to develop improved slope design methodologies which will enable them to enhance the safety of the mine workers and to reduce lost time and increase the production.

A laboratory investigation of the mechanisms of gas migration in coal seams with application to coalbed methane recovery and carbon dioxide sequestration.

A study of Cap rock integrity for CO2 storage projects.


Journals (Total 208 Journal papers)

Full publication list can be found in

De Silva R, *Ranjith PG*, Perera MSA (2017), An Alternative to Conventional Rock Fragmentation Methods Using SCDA: A Review , Energies, vol.9(11), 958; doi: 10.3390/en9110958 (*Selected as the cover page of the journal)*

Xue, Y., *Ranjith, PG*., Gao, F., Zhang, D., Cheng, H., Chong, Z. & Hou, P. (2017) Mechanical behaviour and permeability evolution of gas-containing coal from unloading confining pressure tests In : Journal of Natural Gas & Science Engineering. Vol. 40, 336-346.

Song R, Cui MC, Liu JJ, *Ranjith PG* (2017) A Pore-scale Simulation on Thermal-Hydro-Mechanical CouplingMechanism of Rock, Geofluids Volume 2017, Article ID 7510527, 12 pages

Huang, Y., Yang, S., *Ranjith*,* PG*. and Zhao, J (2017). Strength failure behavior and crack evolution mechanism of granite containing pre-existing non-coplanar holes: Experimental study and particle flow modelling, Computers and Geotechnics, Vol.88,182-198.

Zhou ZQ, *Ranjith PG,* Li SC (2017). Criteria for assessment of internal stability of granular soil, Proceedings of the Institution of Civil Engineers – Geotechnical Engineering, vol.170, 73-83.

Chen S, Yang T, *Ranjith PG*,Wei C (2017). Mechanism of the Two-Phase Flow Model for Water and Gas Based on Adsorption and Desorption in Fractured Coal and Rock, Rock Mechanics and Rock Engineering, vol.50(3), 571-586.

De Silva GPD, *Ranjith PG*, Perera MSA, Dai ZX, Yang SQ (2017). An experimental evaluation of unique CO2 flow behaviour in loosely held fine particles rich sandstone under deep reservoir conditions and influencing factors, Energy, vol.119, 121-137.

Kumari WGP, *Ranjith PG*, Perera MSA, Shao S, Chen BK, Lashin A, Arifi NA, Rathnaweera TD (2017). Mechanical behaviour of Australian Strathbogie granite under in-situ stress and temperature conditions: An application to geothermal energy extraction, Geothermics, vol.65, 44-59.

Rathnaweera TD, *Ranjith PG*, Perera MSA, De Silva VRS (2017). Development of a laboratory-scale numerical model to simulate the mechanical behaviour of deep saline reservoir rocks under varying salinity conditions in uniaxial and triaxial test environments, Measurement: Journal of the international Measurement Confederation, vol.101, 126-137.

Ukwattage NL, *Ranjith PG*, Li X (2017). Steel-making slag for mineral sequestration of carbon dioxide by accelerated carbonation, Measurement: Journal of the international Measurement Confederation, vol.97, 15-22.

Wanniarachchi WAM, *Ranjith PG*, Perera MSA (2017). Shale gas fracturing using foam-based fracturing fluid: a review, Environmental Earth Sciences, vol.76(2).

Mahanta B, Tripathy A, Vishal V, Singh TN, *Ranjith PG* (2017). Effects of strain rate on fracture toughness and energy release rate of gas shales, Engineering Geology, vol.218, 39-49.

Ranathunga AS, Perera MSA, *Ranjith PG*, Wei CH (2017). An experimental investigation of applicability of CO2 enhanced coal bed methane recovery to low rank coal, Fuel, vol.189, 391-399.

Yang SQRanjith PGJing HWTian WLJu Y. (2017) An experimental investigation on thermal damage and failure mechanical behavior of granite after exposure to different high temperature treatments, Geothermics, vol. 65 (1),180-197

Hou R, Zhang K, Sun K, *Ranjith PG* (2017). Discussions on Correction of Goodman Jack Test, Geotechnical Testing Journal, vol. 40(2), 199-209.

Ranathunga AS, Perera MSA, *Ranjith PG* (2016). Influence of CO2 adsorption on the strength and elastic modulus of low rank Australian coal under confining pressure, International Journal of Coal Geology, vol.167, 148-156.

Rathnaweera TD, *Ranjith PG*, Perera MSA (2016). Experimental investigation of geochemical and mineralogical effects of CO2 sequestration on flow characteristics of reservoir rock in deep saline aquifers, Scientific Reports, vol.6(1).

Mahanta B, Singh TN, *Ranjith PG* (2016). Influence of thermal treatment on mode I fracture toughness of certain Indian rocks, Engineering Geology, vol.210, 103-114.

Khandelwal M, Armaghani DJ, Faradonbeh RS, *Ranjith PG*, Ghoraba S (2016). A new model based on gene expression programming to estimate air flow in a single rock joint, Environmental Earth Sciences, vol.75(9).

Rathnaweera TD, Romain L, *Ranjith PG*, Perera MSA (2016). Deformation Mechanics and Acoustic Propagation in Reservoir Rock Under Brine and Oil Saturation: An Experimental Study, Energy Procedia, vol.88, 544-551.

Sirdesai NN, Singh TN, *Ranjith PG*, Singh R (2016). Effect of Varied Durations of Thermal Treatment on the Tensile Strength of Red Sandstone, Rock Mechanics and Rock Engineering, vol.50(1), 205-213.

Refereed Conferences **(Total 89)


Teaching Commitments

  • CIV2242 - Goemechanics.
  • CIV5886 - Infrastructure Geo-mechanics (MSC).
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Last modified: January 2, 2018