Table 4.

Orthogonal test conditions and results.

Operating condition number	Filling wall strength /MPa	Support density/K	Floor tensile strength /MPa	Deformation of surrounding rock /mm
1	30	1.0	1	86.2
2	30	1.25	2	68.5
3	30	1.50	3	55.0
4	40	1.0	2	52.3
5	40	1.25	3	42.1
6	40	1.50	1	65.8
7	50	1.0	3	34.7
8	50	1.25	1	49.5
9	50	1.50	2	39.6