SYMPOSIA PAPER Published: 01 January 1988

A Ground Support Prediction Concept: The Rock Structure Rating (RSR) Model


The Rock Structure Rating (RSR) for prediction of ground support requirements was developed under contract research by the Bureau of Mines. The RSR value index is on a numeric scale of 0 to 100 and is the sum of weighted numerical values determined by considering three basic parameters. Parameter A combines the generic rock type with an index value for rock strength along with the general appraisal of the geologic structure. Parameter B relates the joint pattern with respect to the direction of drive. Parameter C considers the overall rock quality determined by the sum of Parameters A and B along with the degree of joint weathering and alteration, and the anticipated amount of water inflow. Each parameter evaluates the relative support requirement for various geologic and construction factors. The RSR correlation with support further utilizes the “rib ratio” which relates the actual support installation to a theoretical support spacing. Support predictions were determined for steel ribs, shotcrete, and rock bolts. The RSR method of support analysis provides ground support requirements prior to excavation and effective control of ground support practices for project management and operating personnel.

Author Information

Skinner, Eugene, H.
U.S. Department of the Interior, Spokane, WA
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Developed by Committee: D18
Pages: 35–51
DOI: 10.1520/STP48462S
ISBN-EB: 978-0-8031-6775-9
ISBN-13: 978-0-8031-6663-9