Semester

Summer

Date of Graduation

2000

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Mining Engineering

Committee Chair

Syd S. Peng.

Abstract

Variability in the physical properties of coal/rock is a major source of uncertainty encountered around mining environment. It causes a considerable variation in strength/stress estimations of mining structures when the coal/rock properties are used. Therefore, the conventional safety factor method on stability assessment of mining structures is a special case of the more general probabilistic method in that it assumes the variability of coal/rock properties is zero. Although the use of probability and statistical methods in the analysis and design of geotechnical structures has grown rapidly in recent years, its application to mining structure design has been slow due to its relatively larger variation in the geological parameters and computation difficulty for analysis of mining structures.;The purpose of this study is to develop a reliability-based approach for designing and evaluating the stability of mine entry. To address the importance of this research, the conventional method of safety factor concept for mine entry design is reviewed first, then the variability of physical properties of coal/rock is analyzed. The effects of uncertainty due to coal/rock properties on stability design of mine entry are studied. A new approach of reliability-based method (PESM) for the design and evaluation of mine entry is developed. The key points of the PESM are to use the point estimation and safety margin methods for the purposes of parameter approximation and reliability measurement. Therefore, it is relatively easy in computation and yet takes the variability and uncertainties of coal/rock properties into consideration. After comparing the outcomes with the conventional methods, the results of the reliability approach show that the risk assessment by the PESM can be a valuable supplement and complementary to the exiting deterministic procedures such that an overly conservative approach with unknown degree of confidence when using the conventional method for the design and evaluation of mining structures can be greatly reduced.;Although this research focuses on a fundamental study, the results will have significant impacts on current academic researchers, mining operators and government regulators in terms of ground control and mine design. It is anticipated that, by using this approach, the stability assessment will be elevated to a higher level of confidence.

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