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An Investigation of the Interaction of Rock and Types of Rock Bolts for Selected Loading Conditions. First Annual Report.

Authors
Haas-CJ; Clark-GB; Nitzsche-RN
Source
NTIS: PB/267-673 Available for Reference At Bureau Libraries :342 pages
Link
NIOSHTIC No.
10001024
Abstract
The investigation was to determine the effectiveness of grouted bolts in resisting lateral displacement and axial separation along fracture planes, and also to determine if grouted bolts eliminate the axial tensile stress near the anchor and the resulting rock fracture. A finite-element analysis showed that if the rock and resin grout behave in an elastic manner, the post tensioning of a grouted bar will affect mine roof stability only if movement occurs near the collar. An experimental shear test program revealed that both conventional bolts and resin-grouted reinforcing bars significantly increase shear resistance along fracture or bedding plane when the average normal compressive stress on that plane is low (in the order of 25 psi) and when the bolt is oriented so that the shear displacement tends to lengthen the bolt. An increase in shear resistance is also noted at the higher normal pressure of 250 psi; however, the increase is small compared with the corresponding shear resistance without a bolt. Conventional bolts oriented so that they tended to loosen with shear displacement added no significant shear resistance.
Publication Date
19740101
Document Type
CP; Final Contract Report;
Fiscal Year
1974
NTIS Accession No.
PB-267673
NTIS Price
A16
Identifying No.
OFR 2-77
NIOSH Division
SRC;
Source Name
NTIS: PB/267-673 Available for Reference At Bureau Libraries
State
MO;
Performing Organization
University of Missouri
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