Control Mechanism of Rock Burst in the Floor of Roadway Driven along Next Goaf in Thick Coal Seam with Large Obliquity Angle in Deep Well

Table 2

Strata underlying the coal seam and its physical and mechanical parameters.

Lithology	Thickness/m	Internal friction angle/°	Uniaxial tensile strength/MPa	Uniaxial compressive strength/MPa	Protodyakonov coefficient/f
Siltstone	1.7	—	—	50.4	3.5
Medium-grained sandstone	4.2	35.8	10.07	113.7	5.0
Siltstone	4.8	45.8	5.06	35.6	3.5
Coarse-grained sandstone	3.5	41.8	6.73	85.5	5.0
Siltstone	4.8	51.8	6.47	62.1	5.5
Medium-grained sandstone	5.2	47.8	8.27	128.3	5.0