ORCID Profile
0000-0002-6114-5866
Current Organisation
Deakin University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Hydrogeology | Quaternary Environments | Geochemistry | Geomechanics and Resources Geotechnical Engineering | Resources Engineering and Extractive Metallurgy | Physical Geography and Environmental Geoscience | Mining Engineering | Isotope Geochemistry
ANZSRC Socio-Economic Objective (SEO)
Ecosystem Assessment and Management of Fresh, Ground and Surface Water Environments | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Urban Water Evaluation (incl. Water Quality) | Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use) | Coal Mining and Extraction | Mining and Extraction of Precious (Noble) Metal Ores | Workplace Safety | Rural Water Evaluation (incl. Water Quality) |
Related Links
Publications
Quantifying Compressible Groundwater Storage by Combining Cross‐Hole Seismic Surveys and Head Response to Atmospheric Tides
Publisher: American Geophysical Union (AGU)
Date: 08-2018
DOI: 10.1029/2018JF004660
Abstract: Groundwater specific storage varies by orders of magnitude, is difficult to quantify, and prone to significant uncertainty. Estimating specific storage using aquifer testing is h ered by the nonuniqueness in the inversion of head data and the assumptions of the underlying conceptual model. We revisit confined poroelastic theory and reveal that the uniaxial specific storage can be calculated mainly from undrained poroelastic properties, namely, uniaxial bulk modulus, loading efficiency, and the Biot‐Willis coefficient. In addition, literature estimates of the solid grain compressibility enables quantification of subsurface poroelastic parameters using field techniques such as cross‐hole seismic surveys and loading efficiency from the groundwater responses to atmospheric tides. We quantify and compare specific storage depth profiles for two field sites, one with deep aeolian sands and another with smectitic clays. Our new results require bulk density and agree well when compared to previous approaches that rely on porosity estimates. While water in clays responds to stress, detailed sediment characterization from a core illustrates that the majority of water is adsorbed onto minerals leaving only a small fraction free to drain. This, in conjunction with a thorough analysis using our new method, demonstrates that specific storage has a physical upper limit of m −1 . Consequently, if larger values are derived using aquifer hydraulic testing, then the conceptual model that has been used needs reappraisal. Our method can be used to improve confined groundwater storage estimates and refine the conceptual models used to interpret hydraulic aquifer tests.
Technical Note: The use of an interrupted-flow centrifugation method to characterise preferential flow in low permeability media
Publisher: Copernicus GmbH
Date: 07-01-2015
Abstract: Abstract. We present an interrupted-flow centrifugation technique to characterise preferential flow in low permeability media. The method entails a minimum of three phases: centrifuge induced flow, no flow and centrifuge induced flow, which may be repeated several times in order to most effectively characterise multi-rate mass transfer behaviour. In addition, the method enables accurate simulation of relevant in situ total stress conditions during flow by selecting an appropriate centrifugal force level. We demonstrate the utility of the technique for characterising the hydraulic properties of smectite clay dominated core s les. All s les exhibited a non-Fickian tracer breakthrough (early tracer arrival), combined with a decrease in tracer concentration immediately after each period of interrupted-flow. This is indicative of dual (or multi) porosity behaviour, with solute migration predominately via advection during induced flow, and via molecular diffusion (between the preferential flow network(s) and the low hydraulic conductivity domain) during interrupted-flow. Tracer breakthrough curves were simulated using a bespoke dual porosity model with excellent agreement between the data and model output (Nash–Sutcliffe model efficiency coefficient was .97 for all s les). In combination interrupted-flow centrifuge experiments and dual porosity transport modelling are shown to be a powerful method to characterise preferential flow in low permeability media.
MEMS technology and applications in geotechnical monitoring: a review
Publisher: IOP Publishing
Date: 11-02-2022
Abstract: In-situ monitoring is an important aspect of geotechnical projects to ensure safety and optimise design measures. However, existing conventional monitoring instruments are limited in their accuracy, durability, complex and high cost of installation and requirement for ongoing real time measurement. Advancements in sensing technology in recent years have created a unique prospect for geotechnical monitoring to overcome some of those limitations. For this reason, micro-electro-mechanical system (MEMS) technology has gained popularity for geotechnical monitoring. MEMS devices combine both mechanical and electrical components to convert environment system stimuli to electrical signals. MEMS-based sensors provide advantages to traditional sensors in that they are millimetre to micron sized and sufficiently inexpensive to be ubiquitously distributed within an environment or structure. This ensures that the monitoring of the in-situ system goes beyond discrete point data but provides an accurate assessment of the entire structures response. The capability to operate with wireless technology makes MEMS microsensors even more desirable in geotechnical monitoring where dynamic changes in heterogeneous materials at great depth and over large areas are expected. Many of these locations are remote or hazardous to access directly and are thus a target for MEMS development. This paper provides a review of current applications of existing MEMS technology to the field/s of geotechnical engineering and provides a path forward for the expansion of this research and commercialisation of products.
A review of specific storage values from pore pressure response to passive in situ stresses: Implications for sustainable groundwater management
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-11002
Abstract: & & Specific storage (S& sub& s& /sub& ) values are important for analyzing the quantity of stored groundwater and for predicting drawdown to ensure sustainable pumping. This research compiled S& sub& s& /sub& values from multiple available studies based on pore pressure responses to passive stresses, for comparison and discussion with relevant poroelastic theory and groundwater applications. We find that S& sub& s& /sub& values from pore pressure responses to passive in situ stresses ranged from 1.3x10& sup& -7& /sup& to 3.7x10& sup& -5& /sup& m& sup& -1& /sup& (geomean 2.0x10& sup& -6& /sup& m-1, n=64 from 24 studies). This large S& sub& s& /sub& dataset for confined aquifers included both consolidated and unconsolidated strata by extending two recent literature reviews. The dataset included several passive methods: In idual strains from Earth tides and atmospheric loading, their combined effect, and values derived from soil moisture loading due to rainfall events. The range of S& sub& s& /sub& values spans approx. 2 orders of magnitude, far less than for hydraulic conductivity, a finding that has important implications for sustainable groundwater management. Both the range of values and maximum S& sub& s& /sub& values in this large dataset were significantly smaller than S& sub& s& /sub& values commonly applied including laboratory testing of cores, aquifer pump testing and numerical groundwater modelling.& & & & & Results confirm that S& sub& s& /sub& is overestimated by assuming incompressible grains, particularly for consolidated rocks. It was also evident that Ss that commonly assumes uniaxial conditions underestimate S& sub& s& /sub& that accounts for areal or volumetric conditions. & Further research is required to ensure that S& sub& s& /sub& is not underestimated by assuming instantaneous pore pressure response to strains, particularly in low permeability strata. However, in low permeability strata S& sub& s& /sub& could also be overestimated if based on total porosity (or moisture content) rather than a smaller free water content, due to water adsorbed by clay minerals. Further evaluation is also required for influences on S& sub& s& /sub& from monitoring bore construction (ie. screen and casing or grouting), and S& sub& s& /sub& derived from tidal stresses (undrained or constant mass conditions) that could underestimate S& sub& s& /sub& applicable to groundwater pumping (drained or changing mass conditions). In summary, poroelastic effects that are often neglected in groundwater studies are clearly important for quantifying water flow and storage in strata with changing hydraulic stress and loading conditions.& & &
Personal Use of Handheld Fetal Doppler Monitors by Women in New Zealand
Publisher: Victoria University of Wellington Library
Abstract: This qualitative descriptive study explores what factors are driving women in New Zealand to use handheld fetal Doppler monitors during their pregnancy. This is a little explored phenomenon in the literature, and consensus among health professional bodies is that pregnant women should be discouraged from using a handheld fetal Doppler. One concern health professionals hold is that a pregnant woman may be falsely reassured about the condition of her unborn baby and would delay presentation to her lead maternity carer, culminating in stillbirth or neonatal morbidity and mortality that potentially could have been avoided. / br / Six women from a major New Zealand city who were between 20- and 39-weeks’ gestation participated in semi-structured interviews. Thematic analysis, as described by Braun and Clarke, was used to generate five main themes and six subthemes. Control was a strong overarching / theme with subthemes of Fertility and Pregnancy Loss, Ultrasound and Doppler anxieties. Fetal feedback with the subtheme of Bonding was another strong theme. The third and fourth themes were Peer-to-peer education and support and Lay knowledge versus professional knowledge with a / subtheme of Lack of research. The final theme was the Woman-Midwife relationship with a subtheme of More support. / br / Women’s reasons for using a handheld fetal Doppler is for control of their response to the potential of miscarriage. This response is largely one of anxiety, particularly prior to the quickening of the fetus when there is little feedback to prove ongoing fetal life outside of symptoms such as morning sickness. Whilst women gain their information to underpin use of a handheld fetal Doppler via their peer groups in online forums and other internet-based repositories, they are / wanting to enact partnership and shared decision-making with their lead maternity carer (LMC) regarding their use of handheld fetal Doppler monitors in pregnancy. / br / As technologies advance and become more available to non-health professionals, further exploration of use of handheld fetal Doppler monitors by pregnant women is needed in order to better inform women and midwives around the potential benefits and risks. /
Disentangling the groundwater response to Earth and atmospheric tides reveals subsurface processes and properties
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-8665
Abstract: & & In situ quantification of subsurface hydro-geomechanical properties is challenging and requires significant effort. Evolving research illustrates that subtle harmonic components in groundwater head measurements caused by Earth and atmospheric tides can be utilised to explore groundwater systems with little effort compared to traditional investigations. One long standing problem has been that, for dominant tidal components, Earth and atmospheric tides occur at the same frequency which prevents the use of the groundwater response to their in idual forcing to infer subsurface properties. While Acworth et al. (2016) offered a way forward, their approach has assumptions that limit the applicability. Here, we illustrate an extended method that disentangles the borehole water level response and attributes magnitude and phase to their in idual drivers. As a result, we obtain in idual changes in harmonic properties of the drivers and their groundwater response ( litude ratio and phase shift) using borehole water level records from different locations. In conjunction with groundwater flow and poroelastic theory, these properties can be used to infer the state of confinement, quantify specific storage and hydraulic conductivity as well as barometric efficiency of the formation. Further, because the stresses imposed by Earth and atmospheric tides are volumetric and uniaxial, respectively, their in idual responses can be used to reveal strain anisotropy. Our new approach is passive, i.e. it only requires the measurements of atmospheric and groundwater pressure records, and can provide further insight into subsurface processes and properties using information hidden in standard pressure records.& & & & & & & & & Acworth, R. I., Halloran, L. J. S., Rau, G. C., Cuthbert, M. O., and Bernardi, T. L. ( 2016), An objective frequency domain method for quantifying confined aquifer compressible storage using Earth and atmospheric tides, Geophys. Res. Lett., 43, 11,671& #8211 ,678, doi:10.1002/2016GL071328.& &
Supplementary material to "Application of pore water stable isotope method to characterise a wetland system"
Publisher: Copernicus GmbH
Date: 14-05-2018
Application of pore water stable isotope method to characterise a wetland system
Publisher: Copernicus GmbH
Date: 14-05-2018
Abstract: Abstract. Three naturally intact wetland systems (sw s) were characterized based on sediment cores, analysis of surface water, groundwater and porewater stable isotopes. These sw s are classified as temperate highland peat sw s on sandstone (THPSS) and in Australia they are listed as threatened ecological communities. This study is the first application of the stable isotope direct vapour equilibration method in a wetland, enabling quantification of the contributions of evaporation, rainfall and groundwater to sw water balance. This technique enables understanding of the depth of evaporative losses and the relative importance of groundwater flow within the sw environment without the need for intrusive piezometer installation at multiple locations and depths. Additional advantages of the stable isotope direct vapour equilibration technique include detailed spatial and vertical depth profiles of δ18O and δ2H, with good accuracy comparable to the porewater compression technique. Depletion of δ18O and δ2H in porewater with increasing depth (to around 40–60 cm depth) was observed in two sw s, but remained uniform with depth in the third sw . Within the upper surficial zone, the measurements respond to seasonal trends and are subject to evaporation in the capillary zone. Below this depth the pore water δ18O and δ2H signature approaches that of groundwater indicating lateral groundwater contribution. Significant differences were found in stable pore water isotopes for s les collected after dry weather period compared to wet periods where recharge of depleted rainfall was apparent. The organic rich soil in the upper 40–60 cm retains significant saturation following precipitation events and maintains moisture necessary for ecosystem functioning. An important finding for wetland and ecosystem response to changing groundwater conditions (and potential ground movement) are the observations that basal sands underlay the sw s, allowing relatively rapid drainage at the base of the sw and interaction with lateral groundwater contribution. Based on the novel stable isotope direct vapour equilibration analysis of sw sediment, our study identified the following important processes: rapid infiltration of rainfall to the water table with longer retention of moisture in the upper 40–60 cm and lateral groundwater flow contribution at the base. This study also found, that evaporation estimated using stable isotope direct vapour equilibration method is more realistic compared to reference evapotranspiration (ET). Importantly, if sw discharge data were available in combination with pore water isotope profiles, an appropriate transpiration could be determined for these sw s. Based on the results, the groundwater contribution to the sw is a significant component of the water balance during dry period. Our methods could complement other monitoring studies and numerical water balance models to improve prediction of the hydrological response of the sw to changes in water conditions due to natural or anthropogenic influences.
Accelerated gravity testing of aquitard core permeability and implications at formation and regional scale
Publisher: Copernicus GmbH
Date: 15-01-2016
Abstract: Abstract. Evaluating the possibility of leakage through low-permeability geological strata is critically important for sustainable water supplies, the extraction of fuels from coal and other strata, and the confinement of waste within the earth. The current work demonstrates that relatively rapid and realistic vertical hydraulic conductivity (Kv) measurements of aquitard cores using accelerated gravity can constrain and compliment larger-scale assessments of hydraulic connectivity. Steady-state fluid velocity through a low-K porous s le is linearly related to accelerated gravity (g level) in a centrifuge permeameter (CP) unless consolidation or geochemical reactions occur. A CP module was custom designed to fit a standard 2 m diameter geotechnical centrifuge (550 g maximum) with a capacity for s le dimensions up to 100 mm diameter and 200 mm length, and a total stress of ∼ 2 MPa at the base of the core. Formation fluids were used as influent to limit any shrink–swell phenomena, which may alter the permeability. Kv results from CP testing of minimally disturbed cores from three sites within a clayey-silt formation varied from 10−10 to 10−7 m s−1 (number of s les, n = 18). Additional tests were focussed on the Cattle Lane (CL) site, where Kv within the 99 % confidence interval (n = 9) was 1.1 × 10−9 to 2.0 × 10−9 m s−1. These Kv results were very similar to an independent in situ Kv method based on pore pressure propagation though the sequence. However, there was less certainty at two other core sites due to limited and variable Kv data. Blind standard 1 g column tests underestimated Kv compared to CP and in situ Kv data, possibly due to deionised water interactions with clay, and were more time-consuming than CP tests. Our Kv results were compared with the set-up of a flow model for the region, and considered in the context of heterogeneity and preferential flow paths at site and formation scale. Reasonable assessments of leakage and solute transport through aquitards over multi-decadal timescales can be achieved by accelerated core testing together with complimentary hydrogeological monitoring, analysis, and modelling.
Application of the pore water stable isotope method and hydrogeological approaches to characterise a wetland system
Publisher: Copernicus GmbH
Date: 26-11-2018
DOI: 10.5194/HESS-22-6023-2018
Abstract: Abstract. Three naturally intact wetland systems (sw s) were characterised based on sediment cores, analysis of surface water, sw groundwater, regional groundwater and pore water stable isotopes. These sw s are classified as temperate highland peat sw s on sandstone (THPSS) and in Australia they are listed as threatened endangered ecological communities under state and federal legislation. This study applies the stable isotope direct vapour equilibration method in a wetland, aiming at quantification of the contributions of evaporation, rainfall and groundwater to sw water balance. This technique potentially enables understanding of the depth of evaporative losses and the relative importance of groundwater flow within the sw environment without the need for intrusive piezometer installation at multiple locations and depths. Additional advantages of the stable isotope direct vapour equilibration technique include detailed spatial and vertical depth profiles of δ18O and δ2H, with good accuracy comparable to other physical and chemical extraction methods. Depletion of δ18O and δ2H in pore water with increasing depth (to around 40–60 cm depth) was observed in two sw s but remained uniform with depth in the third sw . Within the upper surficial zone, the measurements respond to seasonal trends and are subject to evaporation in the capillary zone. Below this depth the pore water δ18O and δ2H signature approaches that of regional groundwater, indicating lateral groundwater contribution. Significant differences were found in stable pore water isotope s les collected after the dry weather period compared to wet periods where recharge of depleted rainfall (with low δ18O and δ2H values) was apparent. The organic-rich soil in the upper 40 to 60 cm retains significant saturation following precipitation events and maintains moisture necessary for ecosystem functioning. An important finding for wetland and ecosystem response to changing sw groundwater conditions (and potential ground movement) is that basal sands are observed to underlay these sw s, allowing relatively rapid drainage at the base of the sw and lateral groundwater contribution. Based on the novel stable isotope direct vapour equilibration analysis of sw sediment, our study identified the following important processes: rapid infiltration of rainfall to the water table with longer retention of moisture in the upper 40–60 cm and lateral groundwater flow contribution at the base. This study also found that evaporation estimated using the stable isotope direct vapour equilibration method is more realistic compared to reference evapotranspiration (ET). Importantly, if sw discharge data were available in combination with pore water isotope profiles, an appropriate transpiration rate could be determined for these sw s. Based on the results, the groundwater contribution to the sw is a significant and perhaps dominant component of the water balance. Our methods could complement other monitoring studies and numerical water balance models to improve prediction of the hydrological response of the sw to changes in water conditions due to natural or anthropogenic influences.
Accelerated gravity testing of aquitard core permeability and implications at formation and regional scale
Publisher: Copernicus GmbH
Date: 09-03-2015
DOI: 10.5194/HESSD-12-2799-2015
Abstract: Abstract. Evaluating the possibility of leakage through low permeability geological strata is critically important for sustainable water supplies, the extraction of fuels from strata such as coal beds, and the confinement of waste within the earth. The current work demonstrates that relatively rapid and reliable hydraulic conductivity (K) measurement of aquitard cores using accelerated gravity can inform and constrain larger scale assessments of hydraulic connectivity. Steady state fluid velocity through a low K porous s le is linearly related to accelerated gravity (g-level) in a centrifuge permeameter (CP) unless consolidation or geochemical reactions occur. The CP module was custom designed to fit a standard 2 m diameter geotechnical centrifuge (550 g maximum) with a capacity for s le dimensions of 30 to 100 mm diameter and 30 to 200 mm in length, and a maximum total stress of ~2 MPa at the base of the core. Formation fluids were used as influent to limit any shrink–swell phenomena which may alter the permeability. Vertical hydraulic conductivity (Kv) results from CP testing of cores from three sites within the same regional clayey silt formation varied (10−7 to 10−9 m s−1, n = 14). Results at one of these sites (1.1 × 10−10 to 3.5 × 10−9 m s−1, n = 5) that were obtained in 24 h were similar to in situ Kv values (3 × 10−9 m s−1) from pore pressure responses over several weeks within a 30 m clayey sequence. Core scale and in situ Kv results were compared with vertical connectivity within a regional flow model, and considered in the context of heterogeneity and preferential flow paths at site and formation scale. More reliable assessments of leakage and solute transport though aquitards over multi-decadal timescales can be achieved by accelerated core testing together with advanced geostatistical and numerical methods.
Utilizing the Impact of Earth and Atmospheric Tides on Groundwater Systems: A Review Reveals the Future Potential
Publisher: American Geophysical Union (AGU)
Date: 28-05-2019
DOI: 10.1029/2018RG000630
Abstract: Groundwater extraction is increasing rapidly in many areas of the world, causing serious impacts such as falling water tables, ground surface subsidence, water quality degradation, and reduction of stream baseflow on which many ecosystems depend. Methods for understanding and predicting the impacts of groundwater extraction generally lack detailed spatial and temporal knowledge of the subsurface hydrogeomechanical properties. This review provides a comprehensive understanding of Earth and atmospheric tides and their impact on subsurface pore pressure. First, we evaluate the global occurrence of Earth and atmospheric tides. Then, we illustrate their impact on the groundwater response and connect this with the theory of poroelasticity, which underpins quantitative analyses. Finally, we review methods that utilize these impacts to characterize groundwater systems and to quantify their hydrogeomechanical properties. We conclude by highlighting their potential as passive and low‐cost investigation techniques and by outlining the research and developments required to progress and make analyses readily available. Thus, hydrogeomechanical properties of subsurface systems could be obtained at unprecedented spatial and temporal resolution, adding additional value to commonly acquired groundwater and atmospheric pressure data.
Development of IOT-based low-cost MEMS pressure sensor for groundwater level monitoring
Publisher: IOP Publishing
Date: 27-07-2023
Abstract: Groundwater level monitoring is critical to the protection and management of groundwater resources. Properly designed and executed instrumentation can play an important role in increasing the quality and reliability of collected data and reducing total monitoring costs. The efficiency of the instrumentation depends mainly on the accuracy and reliability of the installed sensors. This study presents the testing and application of a cost-effective pressure sensor (0–689 kPa range) for water level monitoring based on microelectromechanical system (MEMS) technology and the internet of things concept. The sensor performance, in terms of accuracy, precision, repeatability, and temperature, was investigated in laboratory columns (with constant water level, increasing and decreasing water levels at various rates) and in situ conditions in an observation bore (with natural groundwater level fluctuations). The results show that the MEMS sensor is capable of providing a reliable and adequate monitoring scheme with an accuracy of 0.31% full scale (FS) (2.13 kPa).
Supplementary material to "Accelerated gravity testing of aquitard core permeability and implications at formation and regional scale"
Publisher: Copernicus GmbH
Date: 09-03-2015
An underground drip water monitoring network to characterize rainfall recharge of groundwater at different geologies, environments, and climates across Australia
Publisher: Copernicus GmbH
Date: 19-09-2023
Hydrogeochemical modelling of corrosive environment contributing to premature failure of anchor bolts in underground coal mines
Publisher: Springer Science and Business Media LLC
Date: 05-2020
Vertical groundwater storage properties and changes in confinement determined using hydraulic head response to atmospheric tides
Publisher: American Geophysical Union (AGU)
Date: 04-2017
DOI: 10.1002/2016WR020311
Vertical hydraulic conductivity of a clayey-silt aquitard: accelerated fluid flow in a centrifuge permeameter compared with in situ conditions
Publisher: Copernicus GmbH
Date: 21-03-2014
DOI: 10.5194/HESSD-11-3155-2014
Abstract: Abstract. Evaluating the possibility of leakage through low permeability geological strata is critically important for sustainable water supplies, extraction of fuels from strata such as coal beds, and confinement of waste within the earth. Characterizing low or negligible flow rates and transport of solutes can require impractically long periods of field or laboratory testing, but is necessary for evaluations over regional areas and over multi-decadal timescales. The current work reports a custom designed centrifuge permeameter (CP) system, which can provide relatively rapid and reliable hydraulic conductivity (K) measurement compared to column permeameter tests at standard gravity (1g). Linear fluid velocity through a low K porous s le is linearly related to g-level during a CP flight unless consolidation or geochemical reactions occur. The CP module is designed to fit within a standard 2 m diameter, geotechnical centrifuge with a capacity for s le dimensions of 30 to 100 mm diameter and 30 to 200 mm in length. At maximum RPM the resultant centrifugal force is equivalent to 550g at base of s le or a total stress of ~2 MPa. K is calculated by measuring influent and effluent volumes. A custom designed mounting system allows minimal disturbance of drill core s les and a centrifugal force that represents realistic in situ stress conditions is applied. Formation fluids were used as influent to limit any shrink-swell phenomena which may alter the resultant K value. Vertical hydraulic conductivity (Kv) results from CP testing of core from the sites in the same clayey silt formation varied (10−7 to 10−9 m s−1, n = 14) but higher than 1g column permeameter tests of adjacent core using deionized water (10−9 to 10−11 m s−1, n = 7). Results at one site were similar to in situ Kv values (3 × 10−9 m s−1) from pore pressure responses within a 30 m clayey sequence in a homogenous area of the formation. Kv sensitivity to s le heterogeneity was observed, and anomalous flow via preferential pathways could be readily identified. Results demonstrate the utility of centrifuge testing for measuring minimum K values that can contribute to assessments of geological formations at large scale. The importance of using realistic stress conditions and influent geochemistry during hydraulic testing is also demonstrated.
Estimation of in-situ hydro-geomechanical properties using the groundwater responses to natural cyclical forcing
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-3635
Abstract: & & Earth and atmospheric tides are prevalent across the land-surface and provide natural forcing to characterise the hydro-geomechanical confined subsurface by using their groundwater response. Since tides are harmonic, their in idual influences on the pressure head can be separated into complex components containing level or pressure magnitudes and phases. The approximated planar strain from Earth tides, and the uniaxial loading from atmospheric tides, allow the estimation of a wide range of values based on hydraulic and poroelastic relationships. With recent research advances, tidal analysis can be used to estimate hydro-geomechanical properties including specific storage, hydraulic conductivity, porosity, shear, Young& #8217 s and Bulk moduli, Skempton& #8217 s and Biot-Willis coefficients and undrained/drained Poisson& #8217 s ratios. This approach does not require any assumption on mineral grain compressibility for unconsolidated systems. However, consolidated materials currently require an a priori estimate of grain compressibility. We applied this method to pressure measurements from different geological settings. The estimated hydro-geomechanical properties comply with theoretically expected values except for Poisson& #8217 s ratio, which differs from laboratory values due to differing confining pressures, and comparatively low frequencies of the Earth and Atmospheric tide signals. However, these estimated values from in-situ data are likely more realistic of the natural hydrogeological response. We anticipate that, by developing methods that routinely can derive engineering geotechnical values through the monitoring of hydraulic head variations, the collection of groundwater pressures will become a priority for large civic excavations or construction, such as mining, in addition to environmental studies and regulatory compliance.& &
Technical Note: The use of an interrupted-flow centrifugation method to characterise preferential flow in low permeability media
Publisher: Copernicus GmbH
Date: 25-09-2015
DOI: 10.5194/HESS-19-3991-2015
Abstract: Abstract. We present an interrupted-flow centrifugation technique to characterise preferential flow in low permeability media. The method entails a minimum of three phases: centrifuge-induced flow, no flow and centrifuge-induced flow, which may be repeated several times in order to most effectively characterise multi-rate mass transfer behaviour. In addition, the method enables accurate simulation of relevant in situ total stress conditions during flow by selecting an appropriate centrifugal force. We demonstrate the utility of the technique for characterising the hydraulic properties of smectite-clay-dominated core s les. All core s les exhibited a non-Fickian tracer breakthrough (early tracer arrival), combined with a decrease in tracer concentration immediately after each period of interrupted flow. This is indicative of dual (or multi-)porosity behaviour, with solute migration predominately via advection during induced flow, and via molecular diffusion (between the preferential flow network(s) and the low hydraulic conductivity domain) during interrupted flow. Tracer breakthrough curves were simulated using a bespoke dual porosity model with excellent agreement between the data and model output (Nash–Sutcliffe model efficiency coefficient was 0.97 for all s les). In combination, interrupted-flow centrifuge experiments and dual porosity transport modelling are shown to be a powerful method to characterise preferential flow in low permeability media.
In situ estimation of subsurface hydro-geomechanical properties using the groundwater response to semi-diurnal Earth and atmospheric tides
Publisher: Copernicus GmbH
Date: 23-08-2022
DOI: 10.5194/HESS-26-4301-2022
Abstract: Abstract. Subsurface hydro-geomechanical properties crucially underpin the management of Earth's resources, yet they are predominantly measured on core s les in the laboratory while little is known about the representativeness of in situ conditions. The impact of Earth and atmospheric tides on borehole water levels is ubiquitous and can be used to characterise the subsurface. We illustrate that disentangling the groundwater response to Earth (M2) and atmospheric tidal (S2) forces in conjunction with established hydraulic and linear poroelastic theories leads to a complete determination of the whole hydro-geomechanical parameter space for unconsolidated systems. Further, the characterisation of consolidated systems is possible when using literature estimates of the grain compressibility. While previous field investigations have assumed a Poisson's ratio from literature values, our new approach allows for its estimation under in situ field conditions. We apply this method to water level and barometric pressure records from four field sites with contrasting hydrogeology. Estimated hydro-geomechanical properties (e.g. specific storage hydraulic conductivity porosity shear, Young's, and bulk moduli Skempton's and Biot–Willis coefficients and undrained or drained Poisson's ratios) are comparable to values reported in the literature, except for consistently negative drained Poisson's ratios, which is surprising. Our results reveal an anisotropic response to strain, which is expected for heterogeneous (layered) lithological profiles. Closer analysis reveals that negative Poisson's ratios can be explained by in situ conditions differing to those from typical laboratory core tests and the small strains generated by Earth and atmospheric tides. Our new approach can be used to passively, and therefore cost-effectively, estimate subsurface hydro-geomechanical properties representative of in situ conditions and it improves our understanding of the relationship between geological heterogeneity and geomechanical behaviour.
In-situ estimation of subsurface hydro-geomechanical properties using the groundwater response to Earth and atmospheric tides
Publisher: Copernicus GmbH
Date: 20-07-2021
Abstract: Abstract. Subsurface hydro-geomechanical properties crucially underpin the management of Earth's resources, yet they are predominantly measured on core-s les in the laboratory while little is known about the representativeness of in-situ conditions. The impact of Earth and atmospheric tides on borehole water levels are ubiquitous and can be used to characterise the subsurface. We illustrate that disentangling the groundwater response to Earth and atmospheric tidal forces in conjunction with hydraulic and linear poroelastic theories leads to a complete determination of the whole hydro-geomechanical parameter space for unconsolidated systems. Further, the characterisation of consolidated systems is possible when using literature estimates of the grain compressibility. While previous field investigations have assumed a Poisson's ratio from literature values, our new approach allows for its estimation under in-situ field conditions. We apply this method to water level and barometric pressure records from four field sites with contrasting hydrogeology. Estimated hydro-geomechanical properties (e.g. specific storage, hydraulic conductivity, porosity, shear-, Young's- and bulk- moduli, Skempton's and Biot-Willis coefficients and undrained/drained Poisson's ratios) are comparable to values reported in the literature, except for consistently negative drained Poisson's ratios which are surprising. Our results reveal an anisotropic response to strain, which is expected for a heterogeneous (layered) lithological profile. Closer analysis reveals that negative Poisson's ratios can be explained by differing in-situ conditions to those from typical laboratory core tests and the small strains generated by Earth and atmospheric tides. Our new approach can be used to passively, and therefore cost-effectively, estimate subsurface hydro-geomechanical properties representative of in-situ conditions. Our method can be used to improve our understanding of the relationship between geological heterogeneity and geomechanical behaviour.
In-situ estimation of subsurface hydro-geomechanical properties using the groundwater response to Earth and atmospheric tides
Publisher: Wiley
Date: 15-12-2020
The Influence of Syndepositional Macropores on the Hydraulic Integrity of Thick Alluvial Clay Aquitards
Publisher: American Geophysical Union (AGU)
Date: 04-0007
DOI: 10.1029/2017WR021681
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Start Date: 2022
End Date: 12-2023
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Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE140100088
Start Date: 2014
End Date: 12-2014
Amount: $150,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP140100153
Start Date: 04-2015
End Date: 12-2018
Amount: $210,000.00
Funder: Australian Research Council
View Funded ActivitySpecial Research Initiatives - Grant ID: NCGRT
Start Date: 07-2009
End Date: 12-2015
Amount: $14,999,996.00
Funder: Australian Research Council
View Funded Activity