New Method to Design Coal Pillar for Lateral Roof Roadway Based on Mining-Induced Stress: A Case Study

Table 2

Mixture material ratio and the physical and mechanical parameters of the strata.

No.	Lithology	Material (kg)				Bulk density (kN/m^3)		Elastic modules (GPa)		Uniaxial compressive strength (Mpa)		Poisson’s ratio
		Sand	CaCO3	Gypsum	Water	Prototype	Model	Prototype	Model	Prototype	Model	Prototype	Model
1	Loose bed	Sand : sawdust = 10 : 1				18∼22.5	12.2	0.1∼5.0	0.00093	5∼13	0.0033	0.35∼0.40	0.35
2	Hard rock	63.36	3.80	8.87	8.45	24.7	15	22	0.13174	37	0.2220	0.20	0.20
3	Soft rock	126.72	17.74	7.60	16.90	20.2	15	8	0.04790	15	0.0900	0.28	0.28
4	Coal seam	44.35	4.44	1.90	5.63	13.5	15	3	0.01796	12	0.0700	0.28	0.28