SCEC Award Number 17157 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Thermal Pressurization in Dilatant Granular Materials: Investigations on Strength Evolution and Strain Localization
Investigator(s)
Name Organization
Ahmed Elbanna University of Illinois at Urbana-Champaign
Other Participants
SCEC Priorities 3c, 3d, 3f SCEC Groups FARM, CS, Geology
Report Due Date 11/30/2018 Date Report Submitted 11/14/2019
Project Abstract
 The scientific objective of this proposal is to make progress towards quantitatively addressing the
following question: How does dilatancy interplay with shear heating to control pore fluid pressure evolution
in sheared fluid infiltrated gouge layers? Thermal pressurization has been hypothesized to be a principal
mechanism for frictional weakening that may hold the keys for interpretation of many seismic observations
such as locking depth, ground motion frequency content and apparent fracture energy. This proposal addresses this critical challenge by numerically modeling shear heating in elastic-visco-plastic gouge layers, accounting for inelastic dilatancy,
under a wide range of pressure, slip rate and initial preparation conditions.
Intellectual Merit , this proposal introduces a set of novel features that go beyond the state of the art. These
include: (1) A rate dependent plasticity model coupled with temperature and pore pressure diffusion
resolving deformation throughout the gouge thickness, (2) A quantitative tool for investigating the competing
effects of dilatancy and shear heating and their implications for stability of sliding, strength evolution and
shear banding, (3) Nucleation and propagation of complex shear bands in extended fault zone models
accounting for both thermal and athermal fluid pressurization
Broader Impacts 1- Training of 1 PhD student: Xiao Ma who recently graduated and joined Exxon Mobile as a research scientist.
2- One journal publication: Ma, X., & Elbanna, A. E. (2018). Strain Localization in Dry Sheared Fault Gouge: A Compactivity based approach. Phys. Rev. E, 98(2), 022906
Exemplary Figure Figure 2