Thermo-Hydro-Mechanical Coupling in Fractured Rock

New findings regarding thermo-hydro-mechanical coupling in fractured rock. Twenty research articles, which were presented at a conference at Bad Honnef in 2000.

(4). The next three papers extend these views by taking a closer look on parameters that govern hydraulic diffusivity in sandstones and other types of rocks. Specific targets addressed are the influence of differential stress on permeability (5), imaging of the fracture geometry (6), and pressure induced variations in the pore geometry (7). Contributions no. 8 to 10 cover investigations of permeability-porosity relationships during rock evolution (8), of the formation, propagation, and roughness of fractures in a plexi-glass block (9), and pressure oscillation effects of two-phase flow under controlled conditions (10). The subsequent four articles focus on diverse modeling approaches. Issues considered are how the geometry and the mechanical behavior of fractures can be characterized by mathematical expressions (11), how the evolution of permeability in a microcracking rock can be expressed by an analytical model (12), deviations from the cubic law for a fracture of varying aperture (13), and the numerical simulation of scale effects in flow through fractures (14). Three further papers refer to in situ observations, being related to topics as the assessment of in situ permeability from the spatio temporal distribution of an aftershock sequence (15), to the scale dependence of hydraulic pathways in crystalline rock (16), and to the significance of pore pressure - stress coupling in deep tunnels and galleries (17).

New insights on rock physics and rock mechanics based on experiments and numerical modeling

Autorentext

mp;nbsp;the past five years or so, studies of rock physics and rock mechanics linked to coupling phenomena have received increased attention. In recognition of this, a Euroconference on thermo-hydro-mechanical coupling in fractured rock was held at Bad Honnef, Germany, in November 2000. Most of the twenty papers collected in this volume were presented at this meeting. The contributions lead to deeper insight in processes where such coupling is relevant.

Inhalt
Borehole Breakouts in Berea Sandstone Reveal a New Fracture Mechanism.- A Model for the Mechanical Behaviour of Bentheim Sandstone in the Brittle Regime.- Failure Model and Spatial Distribution of Damage in Rothbach Sandstone in the Brittle-ductile Transition.- Velocity Measurements and Crack Density Determination During Wet Triaxial Experiments on Oshima and Toki Granites.- Permeability of Triaxially Compressed Sandstone: Influence of Deformation and Strain-rate on Permeability.- Comparison of Measured and Modelled Hydraulic Conductivities of Factured Sandstone Cores.- An Integrated Study on Physical Properties of a KTB Gneiss Sample and Marble from Portugal: Pressure Dependence of the Permeability and Frequency Dependence of the Complex Electrical Impedance.- Permeability-porosity Relationships in Rocks Subjected to Various Evolution Processes.- Slow Crack Propagation and Slip Correlations.- Pressure Oscillation Effects on the Saffman-Taylor Instability.- A Unified Model for Characterisation and Mechanical Behaviour of Rock Fractures.- Analytical Model for Permeability Evolution in Microcracking Rock.- A Simple Model for Deviations from the Cubic Law for a Fracture Undergoing Dilation or Closure.- Scale Effects Related to Flow in Rough Fractures.- Triggering of Seismicity by Pore-pressure Perturbations: Permeability-related Signatures of the Phenomenon.- Scale Dependence of Hydraulic and Structural Parameters in the Crystalline Rock of the KTB.- Mechanisms of Pore Pressure-stress Coupling which Can Adversely Affect Stress Measurements Conducted in Deep Tunnels.- Role of Stress-controlled Flow Pathways in HDR Geothermal Reservoirs.- Porosity and Thermal Conductivity of the Soultz-sous-Forêts Granite.- Interrelations Between Thermal Conductivity and Other PhysicalProperties of Rocks: Experimental Data.