NIOSHTIC-2 Publications Search

Two-leg Longwall Shield Mechanics.

Barczak TM; Schwemmer DE
MISSING :34 pages
This Bureau of Mines report investigates shield mechanics by describing the elastic response and interaction of shield components to applied vertical and horizontal displacements for various canopy and base contact configurations. This research provides information on generalized shield mechanics, which is applicable in describing the behavior of all two-leg shield supports. Utilizing mechanics of materials concepts and known kinematic relationships for two-leg shield supports, free-body diagrams are constructed for shield component illustrating internal axial, shear, and bending moment responses required to maintain equilibrium for each load case evaluated. Predicted shield (component) responses are verified by controlled displacement of instrumented longwall shields in the Bureau's mine roof simulator. Conclusions drawn from these analyses indicate shield structural responses are significantly dependent upon canopy and base contact configurations. Applied displacements also significantly affect shield responses. Horizontal displacement produces different responses than those produced by vertical displacements. The direction of horizontal displacement is also significant in evaluating shield response. Applications of shield mechanics to in situ support monitoring are also discussed. An objective of this research program is to establish unique shield responses to identify in situ load conditions.
Publication Date
Document Type
IH; Report of Investigations;
Fiscal Year
Identifying No.
RI 9220
NIOSH Division
Source Name
Page last reviewed: November 19, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division