Table 1 Rock mechanics parameters of working face.
From: Static expansion fracturing mechanism for enhancing gas permeability in low permeability coal seams
Parameters/unit | Value | Unit |
|---|---|---|
Elastic modulus of coal seam | 3.0 | GPa |
Roof elastic modulus | 5.0 | GPa |
Elastic modulus of base plate | 6.5 | GPa |
Langmuir pressure constant | 3.08 | |
Drainage negative pressure | 20 | kPa |
Initial gas pressure | 20 | kPa |
Tensile strength of coal seam | 0.3 | MPa |
Roof tensile strength | 0.58 | MPa |
Tensile strength of floor | 1.29 | MPa |
Density of seam | 1400 | kg/m3 |
Roof density | 2300 | kg/m3 |
Bottom plate density | 2600 | kg/m3 |
Internal friction angle | 25 | ° |
Roof internal friction angle | 32 | ° |
Internal friction angle of floor | 37 | ° |
Poisson’’s ratio of coal seam | 0.35 | |
Initial permeability | 0.2×e-14 | m2 |
Initial porosity | 4.3 | % |
Gas dynamic viscosity | 1.08×e-5 | Pa·s |
Langmuir volume constant | 0.023 | m3/kg |
Coal matrix size | 1.88 | m |
Single-hole diffusion coefficient | 5.61×e-10 | m2/s |
Geothermal temperature | 296 | K |
