HR: 08:30h
AN: H51B-03    [PDF]
TI: Hydraulic Fracturing in Cohesionless Particulate Materials
AU: * Chang, H
EM: gte004k@prism.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332-0355 United States
AU: Germanovich, L N
EM: leonid@ce.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332-0355 United States
AU: Wu, R
EM: gte755q@prism.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332-0355 United States
AU: Santamarina, J C
EM: carlos@ce.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332-0355 United States
AU: Dijk, P E
EM: peter.dijk@ce.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332-0355 United States
AB: This work examines the mechanisms of hydraulic fracturing in cohesionless particulate materials. The fracturing liquid is injected into dry particulate materials, which are practically cohesionless. The liquid flow is localized in thin self-propagating crack-like conduits (Figure 1). By analogy we call them `cracks' or `hydraulic fractures.' When a fracture propagates in a solid, new surfaces are created by breaking material bonds. Consequently, the material is in tension at the fracture tip. Because the particulate material is already `fractured,' no new surface is created and no fracturing process per se is involved. Moreover, all material parts are in compression since the material cannot bear any tension. Therefore, the conventional fracture mechanics principles cannot be directly applied. Based on the laboratory observations, performed on three dry particulate materials (Georgia Red Clay, silica flour, and fine sand), this study offers a physical concept to explain the observed phenomenon. The goal of this study is to determine the controlling parameters of fracture behavior and to quantify their effects. The presented model is based on fracture propagation due to unloading caused by the opening of the propagating fracture. The sufficiently unloaded particulate material yields in the fracture process zone, creating inclined slip planes (shear bands) that are kinematically associated with mode I fracture opening near the process zone. This creates space for continued liquid flow.
UR: http://www.ce.gatech.edu/~leonid/rockmechgroup/research.html
DE: 1719 Hydrology
DE: 3210 Modeling
DE: 5104 Fracture and flow
SC: Hydrology [H]
MN: 2003 Fall Meeting