Numerical Simulation of Gas-Solid Coupling in Pressure-Relief Gas Drainage of Short-Distance and Underprotective Steeply Inclined Coal Seam Mining

Table 1

The mechanical parameters coal and rock.

Lithology	Volume-weight/t/m^3	Poisson’s ratio	Internal friction angle /°	Cohesion/MPa	Strength of extension /MPa	Strength of compression /MPa	Elasticity modulus /GPa	Bulk modulus /GPa	Shear modulus /GPa
Medium-grain sandstone	2.55	0.27	36.00	5.88	3.43	40.27	10.87	7.88	4.28
Sandy mudstone	2.53	0.21	31.50	5.65	3.70	34.56	9.23	5.30	3.81
Mudstone, sandy mudstone	2.50	0.20	31.00	5.03	3.43	29.54	7.80	4.33	3.25
Quartz sandstone	2.59	0.23	37.50	7.23	4.45	47.04	12.85	7.93	5.22
Argillaceous siltstone	2.53	0.20	38.00	5.43	3.50	33.64	8.96	4.98	3.73
No. 2-1 coal	1.46	0.33	30.00	0.75	0.55	4.05	1.95	1.91	0.73
Mudstone	2.52	0.20	30.00	4.19	2.56	27.43	7.20	4.00	3.00
Siliceous mudstone, calcareous marl	2.61	0.20	33.00	7.84	4.95	49.65	13.62	7.57	5.67
No. 1-8 coal	1.42	0.30	32.00	1.16	0.87	6.20	1.48	1.23	0.57
Sandstone	2.58	0.21	40.50	6.54	4.00	42.71	11.58	6.66	4.79
Limestone	2.55	0.20	36.50	6.12	4.22	35.45	9.48	5.27	3.95
Aluminum mudstone	2.60	0.26	33.00	4.87	2.89	32.82	8.73	6.06	3.46
Limestone	2.60	0.22	40.50	7.58	5.56	41.32	11.18	6.65	4.58