| 摘要 |
PROBLEM TO BE SOLVED: To obtain a notched pipe anchor, which displays high holding capacity even to a cracked foundation and can be installed simply and rapidly. SOLUTION: In the pipe anchor, which has a hollow anchor body 1 for usage on a mine working field and a tunnel excavation field and in which a screw contour 2 is formed on the surface of an external cylinder at least partially and the screw contour 2 is composed of a trapezoidal screw consisting of a bottom-section region 4 parallel with an axis and a back section 3 parallel with the axis, the gradeαof a side on the reverse side to at least the driving- direction side of a trapezoidal cross section is set in 10 deg.-45 deg., and size (a) in the axial direction of the bottom-section region 4 and/or size (b) in the axial direction of the back section region 3 is set at the 0.1-0.04 times of the diameter (d) of the anchor body 1. It is preferable that height (h) in the radial direction of the anchor body 1 of the screw contour 2 is set in size at the 0.25-0.75 times of the wall thickness of the anchor body 1, and the screw pitches of the screw contour 2 are set in 10-40 mm.
|
