Analysis of Strata Behavior Process Characteristics of Gob-Side Entry Retaining with Roof Cutting and Pressure Releasing Based on Composite Roof Structure

Table 1

Modeling parameters of each rock layer.

Lithology	Bulk density (kN/m^3)	Tensile strength (MPa)	Internal friction angle (°)	Cohesion (MPa)	Bulk modulus (GPa)	Shear modulus (GPa)
Mudstone	23	3.2	28	0.2	0.20	0.15
Fine sandstone	24	7.3	32	1.0	3.81	3.05
Siltstone	23	4.3	32	0.8	2.11	1.86
Medium sandstone	25	8.4	33	2.6	11.49	7.26