Table 2 Comparison of dense drilling angle.

From: Research on the pressure relief mechanism and application of roof dense drilling of gob side entry retaining by roadway-side filling

Scheme No.

Dense drilling angle/°

Invariant

A0

No dense drilling

Roadway section size,

Surrounding rock support strength,

Coal seam thickness,

Yieldable concrete parameters,

Dense drilling height

A1

0°

A2

5°

A3

10°

A4

15°

A5

20°

A6

25°

A7

30°

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