Hydraulic-Mechanical Coupling Model with Dual-Porosity Dual-Permeability for Anisotropy Coal Seams and Its Application in Mine Gas Extraction

Table 1

Related parameters for simulation of underground gas extraction.

Parameter	Value	Source
Initial porosity of the matrix,	0.045	Experiments
Gas dynamic viscosity, μ (Pa·s)	1.84 × 10^−5	[38]
Langmuir volume constants, a (m^3·kg^−1)	2.45	Experiments
Langmuir pressure constants, b (MPa^−1)	0.018	Experiments
Width of the coal matrix, an (m)	2 × 10^−2	Estimation
Initial fracture porosity,	0.015	Experiments
Desorption time, τ (days)	9.2	[12]
Poisson’s ratio, ν	0.28	Experiments
Klinkenberg factor, m (MPa)	0.76	[26]
Coal seam temperature, T (K)	305.15	Field test
Strain constant, εl	0.0083	[27]
Coal skeleton density, ρs (kg·m^−3)	1420	Experiments
Pressure constant, (MPa)	3.55	[27]
Initial gas pressure, (MPa)	1.52	Field test