Table 1 Calculation results of pressure relief zone parameters of different borehole diameters.

From: Study on the pressure relief energy dissipation law of variable-diameter boreholes in roadway surrounding rock

Borehole diameter/mm

The maximum radius of borehole pressure relief area/m

The angle between the maximum radius direction and the horizontal direction of the pressure relief zone/°

100

0.13

0

150

0.19

0

200

0.26

0

250

0.32

0

300

0.39

0

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