A Numeric Analysis of the Effects Different Factors Have on Slotted Drilling
LIN Bai-quan
YANG Wei
WU Hai-jin
MENG Fan-wei
ZHAO Yan-xu
ZHAI Cheng
Abstract：The"stopper effect"was found to be the main factor limiting the range of pressure relief from stress-relief drillings.By studying the stress around a drilling it was determined that slotting the drilled hole can eliminate this negative effect.It was observed that the slot height had little effect on pressure relief in the coal above the drilling.Still,consideration of creep deformation and other factors suggests the slot height should be grater than 1 6 mm.On the other hand,slot depth greatly affects pressure relief in the coal above the drilling.Changing slot depth to 0.77 m from 0.227 m caused the stress in the coal measured 1.03 meters above the slot to drop to 0.31 MPa from 6.2 MPa.Hence it is possible to increase the effective range of the drilling by increasing the slot depth.The greater range of pressure relief allows the effect from adjacent drillings to overlap.Hence several drillings must be regarded together as a system.
Keywords：slotted drillingslot"stopper effect"stresseffected range
Publication Date：2010-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 153-157 )