Table 1 Physical and mechanical parameters of coal and rock.

From: Overburden structure fracture evolution and ground pressure behavior under oblique residual coal pillars in thick seam mining

Rock layers

Thickness/m

Buried depth (m)

Test weight (kg·m− 3)

Volume force (kN/m³)

Elastic modulus (MPa)

Internal friction angle (°)

Loess

39.50

39.50

1 600

16.00

300

15

Mudstone, conglomerate

169.30

178.85

2 220

22.20

2 790

38

Sandy mudstone

46.25

225.00

2 220

22.20

2 790

35

Conglomerate

8.47

233.47

2 220

22.20

2 790

35

Silty mudstone

14.77

248.24

2 530

25.30

1 740

28

Mudstone

14.52

262.76

2 530

24.20

1 400

31

Fine sandstone

16.45

279.21

2 420

26.40

4 130

26

Argillaceous siltstone

7.68

286.89

2 640

25.30

1 740

25

Silty mudstone

19.68

306.57

2 530

25.30

1 740

26

Argillaceous siltstone

14.35

320.92

2 530

25.30

1 740

36

Medium-grained sandstone

36.98

356.90

2 530

23.60

5 200

32

3# coal seam

0.88

357.78

1 300

13.00

800

35

Fine sandstone

10.43

368.21

2 640

26.40

4 130

35

Mudstone

2.76

372.42

2 420

24.20

1 400

36

Coarse sandstone

12.14

384.56

2 410

24.10

2 860

25

Fine sandstone

13.85

398.41

2 640

26.40

4 130

35

Silty mudstone

18.75

417.16

2 530

25.30

1 740

35

Fine sandstone

37.66

454.82

2 640

26.40

4 130

25

Siltstone

18.28

473.10

2 530

25.30

1 740

32

Silty mudstone

4.50

477.60

2 530

25.30

1 400

32

5# coal seam

33.48

507.60

1 300

13.00

800

35

Coarse sandstone

9.12

516.72

2 630

23.60

2 860

35

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