Abstract: For underground roadway surface irregularities, bolts tail tension, torsion, bending combination of stress rupture phenomenon, theoretical analysis and numerical simulation methods used to study the effects of different spherical washers on bolts tail of the force. Analysis of the impact of the angle θ, the coefficient of friction between the tray and the spherical washer on bolt tail stress and deformation, air obtained spherical washers can be a good improvement in the force bolt tail. Obtain spherical washers can be well optimized force bolt tail. Preload force 30kN, bolts tail force reduced by 66% by used spherical washers; the larger of the angle θ, the smaller of friction coefficient, bolts tail bending angle is smaller; when the angle θ take 30 °, ball pad aligning Range Max.

Key words: coefficient of friction &mu