SCEC Award Number 24168 View PDF
Proposal Category Individual Research Project (Single Investigator / Institution)
Proposal Title Laboratory calibration of visco-elasto-plastic damage model
Investigator(s)
Name Organization
Roman Makhnenko University of Illinois at Urbana-Champaign
SCEC Milestones D1-1, D2-2, B2-2, B3-3 SCEC Groups SDOT, FARM, EFP
Report Due Date 03/15/2025 Date Report Submitted 04/07/2025
Project Abstract
 Experiments on brittle creep behavior of fluid-saturated rock are conducted in order to investigate the laboratory-scale analog for earthquake nucleation process. The impact of time-dependent deformation on fluid transport properties and microseismic activity in Berea sandstone under triaxial loading condition is investigated. During a stress-stepping test, subcritical crack growth appears to lead to progressive damage, which is monitored through accumulation of volume and shear strain. The results demonstrate an exponential decrease in both bulk and shear viscosities as deviatoric stress increases, highlighting the role of time-dependent deformation in subcritical stress regime. Notably, intrinsic permeability decreases despite the formation of microcracks, suggesting that crack closure due to external confinement outweighed any pore network connectivity enhancements. This study highlights the importance of incorporating subcritical time-dependent deformation in geomechanical models, as it significantly influences fluid flow through rock.
Intellectual Merit This laboratory study is aimed at characterizing the earthquake nucleation processes in fluid-saturated rock and directly contributes to Fault and Rupture Mechanics (FARM) working group research objectives. In addition, it is concerned with the issues pertaining to the role of pore fluids in time-dependent deformation, as well as the sensitivity of rock rheology and failure to applied stresses and pore pressures thus directly addressing the research priorities of Stress and Deformation Over Time (SDOT) working group.
Broader Impacts The project allowed establishing testing procedures for fluid-saturated rock with registration of fluid flow and acoustic emission under representative conditions. The obtained results will be disseminated at the upcoming SCEC annual meeting and ARMA Symposium. Some of the datasets will be used by the students in rock mechanics and geoenergy courses taught by the PI. On the large scale, development of the constitutive laws for the inelastic time-dependent response of fluid-saturated rock should improve the predictability of hydromechanical models dealing with earthquake nucleation and precursory processes. The future work will involve establishing relationships for fractured tight rock.
Project Participants Investigator: Roman Y. Makhnenko
Graduate students: Nikita Bondarenko, Ph.D., and Shirui Ding, M.S.
All the experiments were performed in the rock mechanics laboratory at the University of Illinois at Urbana-Champaign.
Exemplary Figure Figure 1. Summary of explored rock-fluid interaction mechanisms that are involved in the earthquake nucleation process and significantly affecting rock properties.
Linked Publications

Add missing publication or edit citation shown. Enter the SCEC project ID to link publication.