Main factors that control roadway damage when a steeply dipping coal seam crosses a fault

Figures & data

Table 1. The columnar and mechanical parameters of coal and rock strata.

Rock layers	Columnar	Thickness (m)	Tensile strength (MPa)	Friction angle (°)	Cohesion (MPa)	Elastic modulus (GPa)	Density (kN/m^3)
Siltstone		3.88	2.3	45	2.3	5.5	2530
14# coal seam		0.82	0.27	35	1.3	1.0	1350
Silty shale		2.33	2.2	41	2.5	3.6	2300
Fine sandstone		4.51	3.4	29	13.1	6.0	2540
Carbonaceous shale		2.36	2.2	41	2.5	3.6	2500
Coarse sandstone		14.8	4.2	30	13.1	19.0	2530
Siltstone		4.00	2.3	45	2.3	5.5	2530
Argillaceous siltstone		0.50	2.2	41	2.5	3.6	2600
15# coal seam		4.91	0.44	45	2.3	1.0	1350
Argillaceous siltstone		2.30	2.2	41	2.5	3.6	2600
Siltstone		0.56	2.3	45	2.3	5.5	2530
16# coal seam		0.60	0.27	35	1.3	1.0	1350
Fine sandstone		7.00	3.4	29	13.1	6.0	2540
Coarse sandstone		28.0	4.2	30	13.1	19.0	2530

Figure 1. Layout and support section of the roadway: (a) relationship between the roadway layout and fault location and (b) roadway position and support section.

Figure 2. Physical similarity simulation experimental model and monitoring equipment.

Figure 3. Mining load transfer law of the working face: (a) roof caving form of the working face crossing a fault and (b) distribution characteristics of the abutment pressure in the working face.

Table 2. Characteristic parameters of ground pressure behaviour in working face.

Phenomenon	Distance from fault (m)	Advance distance (m)	Front of the working face			Behind the working face
			Peak value (MPa)	Distance from coal wall (m)	Stress concentration factor	Peak value (MPa)	Distance from coal wall (m)	Stress concentration factor
First weighting	75	65	16.36	5.3	1.86	11.87	6.7	1.36
1st periodic weighting	53	87	19.67	7.2	2.25	13.65	6.5	1.56
2nd periodic weighting	33	107	22.87	6.1	2.61	16.97	5.4	1.94
3rd periodic weighting	9	131	29.37	8.5	3.36	27.45	7.4	3.14
4th periodic weighting	−6	146	19.45	7.6	2.22	18.65	6.2	2.13
5th periodic weighting	−24	164	20.34	5.7	2.32	19.45	6.5	2.22

Figure 4. Load transfer path of the working face crossing a fault: (a) working face away from the fault and (b) working face near the fault.

Figure 5. Characteristic impacts of mining load strength.

Figure 6. 3D numerical calculation model.

Figure 7. Stress distribution characteristics of roadway surrounding rock at different fault locations: (a) no fault, (b) fault 1 m from the left side, (c) fault 1 m from the right side, (d) fault located on the left side, (e) fault located in the middle of the roadway, and (f) fault located on the right side.

Figure 8. Deflection characteristics of the first principal stress in the roadway surrounding rock at different fault positions: (a) no fault, (b) fault 1 m from the left side, (c) fault 1 m from the right side, (d) fault located on the left side, (e) fault located in the middle of the roadway, and (f) fault located on the right side.

Table 3. The maximum deflection angle (θ_max) of the first principal stress in surrounding rock at different fault locations.

Fault location	Roof	Floor	Right side	Left side
No fault	95.3°	109°	58°	42.5°
Fault 1 m from the left side	120°	108°	58.4°	72.3°
Fault 1 m from the right side	117°	106°	80.7°	55.2°
Fault located on the left side	130°	121°	45°	49.4°
Fault located in the middle of roadway	86.5°	72.6°	51.3°	43.4°
Fault located on the right side	108°	125°	55.5°	46.5°

Figure 9. Roadway surrounding rock displacement distribution at different fault positions: (a) no fault, (b) fault 1 m from left side, (c) fault 1 m from right side, (d) fault located on left side, (e) fault located in the middle of roadway, and (f) fault located on the right side.

Table 4. Surface deformation of roadway surrounding rock at different fault locations. (unit: mm).

Fault location	Roof	Floor	Right side	Left side
No fault	46	48	40	26
Fault 1 m from the left side	93	108	66	110
Fault 1 m from the right side	87	65	81	41
Fault located on the left side	121	101	79	75
Fault located in the middle of roadway	85	74	46	26
Fault located on the right side	100	61	19	46

Figure 10. Stress distribution characteristics of roadway surrounding rock under different load strengths: (a) load strength coefficient of 2.61, (b) load strength coefficient of 3.36, (c) load strength coefficient of 1.87, and (d) load strength coefficient of 2.22.

Figure 11. Deflection characteristics of the first principal stress of the roadway surrounding rock under different load strengths: (a) load strength coefficient of 2.61, (b) load strength coefficient of 3.36, (c) load strength coefficient of 1.87, and (d) load strength coefficient of 2.22.

Table 5. The maximum deflection angle (θ_max) of the first principal stress in surrounding rock with different load strength.

Load strength coefficient	Roof	Floor	Right side	Left side
2.61	89.7°	129°	59.4°	37°
3.36	92.8°	132°	59.1°	41°
1.87	98.4°	107°	58°	31.3°
2.22	95.3°	112°	58°	34.3°

Figure 12. Roadway surrounding rock displacement distribution under different load strengths: (a) load strength coefficient of 2.61, (b) load strength coefficient of 3.36, (c) load strength coefficient of 1.87, and (d) load strength coefficient of 2.22.

Table 6. Surface deformation of roadway surrounding rock with different load strength. (unit: mm).

Load strength coefficient	Roof	Floor	Right side	Left side
2.61	106	52	64	44
3.36	147	62	105	57
1.87	84	45	39	18
2.22	94	51	48	40

Data availability statement

Relevant data are listed in the paper.