Analysis of the Historic Bondi Pumping Chamber Case Study Using the Adjusted Voussoir Beam Analog.

Analytical methods in engineering design use simplifying assumptions to reduce the number of variables considered for a given problem. In rock engineering design, this reduction in complexity increases practical applicability but often must be applied with a degree of conservatism, as relevant mechanisms may remain unaccounted for in a given analytical solution. To date, the voussoir beam analog has seen relatively limited application to complex roof stability problems. Previous research by the authors has used numerical modeling to expand the voussoir beam analog by developing analytical solution adjustments to account for important factors such as horizontal bedding and passive bolts. This paper presents the application of the adjusted voussoir beam analytical solution in a case study of the historic Bondi Pumping Chamber. Discrete element method numerical models are also presented to elucidate the mechanisms governing stability and deflection of the supported roof beam. The results of this study provide a novel real-world validation of the adjusted voussoir beam analog and insight into its practical applicability and limitations. Highlights: Successful field application of a voussoir beam analytical solution that accounts for supported flat-roof excavations in discontinuous rockmasses Effects of roof support installation timing and variations in discontinuity strength and stiffness identified through numerical models Self-supporting capacity of flat-roof excavations explored through comparison of numerical and analytical results [ABSTRACT FROM AUTHOR]