Design of Underground Structures Under Geotechnical Uncertainties

Underground structures are one of the essential design elements in mineral extraction, public transportation, oil storage, deep geological repository, and other public infrastructure facilities. Examples of underground structures are protective pillars, roadways, tunnels, storage space, caverns, shafts, adit, ramps, crosscuts, barrier pillars, stook, and others. Designing stable designs of underground structures is a challenging task due to inherent variability in the relevant geotechnical parameters. The conventional design process considers the static and absolute values of the design parameters and ignores uncertainties and time-dependent changes. This practice usually leads to failures of the underground structures which incur incalculable losses in terms of accidents and downtime in underground activities. The shortcomings of the deterministic design process to ignore the design uncertainties can be resolved by the reliability-based design process which includes the uncertainties in the design process. This chapter describes the design process based on reliability principles and presents some practical examples to apply this method in designing stable underground pillars in coal mines.