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The Use of Rock Bolts or Wire Rope to Increase the Strength of Fractured Model Pillars.

Authors
Horino-FG; Duvall-WI; Brady-BT
Source
NTIS: PB 205 153 :24 pages
Link
NIOSHTIC No.
10000978
Abstract
The Bureau of Mines conducted compressive strength tests on model pillars of selected rock types with each pillar containing a critically oriented plane of weakness. The objective of these tests was to determine if a significant increase in the strength of the model pillar could be obtained by either (1) installing tensioned rock bolts through the pillar and normal to the plane of weakness, or (2) wrapping tensioned steel wire ropes around the pillar at uniformly spaced intervals along the pillar. Equations based on coulomb's failure criterion are developed to predict uniaxial compressive strength of model pillars that are either rock-bolted or wire-roped. Laboratory compressive strength tests on unbolted and bolted model pillars of sandstone, marble, Indiana limestone, and oil shale containing a plane of weakness oriented at 45 deg showed that the bolted pillars are stronger than the unbolted pillars by 84, 31, 52, and 28 percent, respectively. Laboratory compressive strength tests on nonroped and roped model pillars of Texas limestone, sandstone, and granite containing planes of weakness showed that the roped pillars were stronger than the nonroped pillars by factors ranging from 1.01 to 2.41, Depending upon the angle of the plane of weakness and the rock type. Rocks with a low young's modulus benefited most by the wire-roping technique.
Publication Date
19710101
Document Type
IH; Report of Investigations
Fiscal Year
1971
NTIS Accession No.
PB-205153
NTIS Price
A03
Identifying No.
RI 7568
NIOSH Division
SRC;
Source Name
NTIS: PB 205 153
State
IN; TX;
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