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Laboratory Studies of Yielding Rock Bolts.

Authors
Conway-JP; Dar-SM; Stears-JH; Mcwilliams-PC
Source
NTIS: PB 245 560 :40 pages
Link
NIOSHTIC No.
10000890
Abstract
The yielding-rock-bolt concept, as developed in South Africa, consists of a smooth-bore die or collar fitted to a standard rock bolt. Laboratory testing at the Bureau of Mines Spokane Mining Research Center under slow and fast strain rates showed that extrusion loads can be controlled by varying the configuration of the die bore and that theoretical analysis (using basically sachs' theory of wire drawing) predicts extrusion loads of the different die-bore configurations. A derived equation, based on this research, can be used for designed die-thread combinations for any desired extrusion load. Dynamic loading resulted in slightly higher loads (15 percent) than static loading. The strain hardening effect, which increases yield and ultimate strength, was partly offset by adiabatic heating of the threads, which decreases strength.
Publication Date
19750101
Document Type
IH; Report of Investigations
Fiscal Year
1975
NTIS Accession No.
PB-245560
NTIS Price
A04
Identifying No.
RI 8058
NIOSH Division
SRC;
Source Name
NTIS: PB 245 560
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