Acta Geotechnica

, Volume 11, Issue 5, pp 969–986

Stress-dependent hydraulic properties of clayey-silt aquitards in eastern Australia

  • S. Bouzalakos
  • R. A. Crane
  • D. McGeeney
  • W. A. Timms
Research Paper

DOI: 10.1007/s11440-016-0455-7

Cite this article as:
Bouzalakos, S., Crane, R.A., McGeeney, D. et al. Acta Geotech. (2016) 11: 969. doi:10.1007/s11440-016-0455-7
  • 291 Downloads

Abstract

Clayey-silt aquitards account for 60 % of the ~100-m-thick alluvial sediment sequence in the Gunnedah area of eastern Australia. To better understand the stress-dependent hydraulic properties of these low-permeability units, oedometer test data presented for the first time in this study have been integrated with geotechnical centrifuge permeameter tests. Estimates of vertical pre-consolidation effective stress (\(\sigma_{\text{p}}^{'}\)), vertical in situ effective stress (\(\sigma_{\text{i}}^{'}\)), and over-consolidation ratio (OCR) were used to determine whether centrifugation stresses caused compression of core samples, and the degree to which vertical hydraulic conductivity (Kv) assessments were representative of the core samples tested. Results suggest that minimally disturbed drill core from semi-consolidated sediments (e.g., alluvial, colluvial, and eolian deposits) evaluated in this study should have target centrifugation stress less than \(\sigma_{\text{p}}^{'}, \) where OCR < 1 and \(\sigma_{\text{i}}^{'}\) where OCR > 1 to avoid significant changes in hydraulic properties during plastic straining. The results also imply that the stress-dependent response of aquitards is critical to understand the sensitivity of groundwater resources in areas with multiple stakeholders such as mining, coal seam gas, and agriculture developments. Groundwater in alluvial sediments that is essential for irrigation, water supply, and base flows to rivers must be sufficiently disconnected from groundwater in coal seams that are depressurized for extraction of energy resources.

Keywords

Aquitards Consolidation Geotechnical centrifuge Groundwater drawdown Hydraulic conductivity Stress history 

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • S. Bouzalakos
    • 1
    • 2
  • R. A. Crane
    • 1
    • 3
  • D. McGeeney
    • 1
    • 3
  • W. A. Timms
    • 1
    • 2
  1. 1.UNSW Connected Waters InitiativeNational Centre for Groundwater Research and TrainingSydneyAustralia
  2. 2.Australian Centre for Sustainable Mining Practices, School of Mining EngineeringThe University of New South WalesSydneyAustralia
  3. 3.Water Research Laboratory, School of Civil and Environmental EngineeringThe University of New South WalesManly ValeAustralia

Personalised recommendations