Coupled flow network and discrete element modeling of injection-induced crack propagation and coalescence in brittle rock

We present a numerical analysis on injection-induced crack propagation and coalescence in brittle rock. The DEM network coupling model in PFC is modified to capture the evolution of fracture geometry. An improved fluid flow model for fractured porous media is proposed and coupled with a bond-based D...

Full description

Saved in:
Bibliographic Details
Published in:Acta geotechnica 2019-06, Vol.14 (3), p.843-868
Main Authors: Liu, Guang, Sun, WaiChing, Lowinger, Steven M., Zhang, ZhenHua, Huang, Ming, Peng, Jun
Format: Article
Language:English
Subjects:
Coalescence
Coalescing
Complex Fluids and Microfluidics
Compressive strength
Computational fluid dynamics
Computer simulation
Crack propagation
Cracks
Direction
Discrete element method
Engineering
Fluid flow
Fluid injection
Foundations
Fracture mechanics
Fractures
Geoengineering
Geotechnical Engineering & Applied Earth Sciences
Grain
Granite
Graph theory
Hydraulics
Injection
Interactions
Mathematical models
Modelling
Numerical analysis
Parameter identification
Parameters
Porous media
Research Paper
Rocks
Soft and Granular Matter
Soil Science & Conservation
Solid Mechanics
Stone
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present a numerical analysis on injection-induced crack propagation and coalescence in brittle rock. The DEM network coupling model in PFC is modified to capture the evolution of fracture geometry. An improved fluid flow model for fractured porous media is proposed and coupled with a bond-based DEM model to simulate the interactions among cracks induced by injecting fluid in two nearby flaws at identical injection rates. The material parameters are calibrated based on the macro-properties of Lac du Bonnet granite and KGD solution. A grain-based model, which generates larger grains from assembles of particles bonded together, is calibrated to identify the microscopic mechanical and hydraulic parameters of Lac du Bonnet granite such that the DEM model yields a ratio between the compressive and tensile strength consistent with experiments. The simulations of fluid injection reveal that the initial flaw direction plays a crucial role in crack interaction and coalescence pattern. When two initial flaws are aligned, cracks generally propagate faster. Some geometrical measures from graph theory are used to analyze the geometry and connectivity of the crack network. The results reveal that initial flaws in the same direction may lead to a well-connected crack network with higher global efficiency.
ISSN:1861-1125
1861-1133
DOI:10.1007/s11440-018-0682-1