Innovative Control Technique for the Floor Heave in Goaf-Side Entry Retaining Based on Pressure Relief by Roof Cutting

Table 1

Physicomechanical parameters of strata.

Lithology	Density/(kg/m^3)	Bulk modulus/(GPa)	Tensile strength/(MPa)	Shear modulus/(GPa)	Angle of internal friction/(°)	Cohesion/(MPa)
Argillaceous siltstone	2,350	3.36	4.21	2.3	35	1.8
Fine sandstone	2,570	6.25	9.5	3.57	31	2.4
Silty mudstone	2,400	10.76	1.64	3.2	30	1.4
Coal seam	1,370	2.8	0.4	1.2	27	0.6
Mudstone	2,463	3.94	1.68	2.6	30	1.2
C30 concrete block	2,350	7.6	2.5	11.2	32	2.1