National Exams — 18-Geol-A5, Rock Mechanics. Closed-book, 3-hour exam; 5 questions
of 20 marks each (80 marks total); candidates were instructed to answer only 4 of the 5 — all 5 are answered below. Every page footer of the paper reads “May 2019”.
Reference texts:
- Bieniawski, Z.T. (1989), Engineering Rock Mass Classifications, Wiley.
- Barton, N., Lien, R. & Lunde, J. (1974), “Engineering Classification of Rock Masses for the
Design of Tunnel Support” (the NGI Q-system).
- Brady, B.H.G. & Brown, E.T., Rock Mechanics for Underground Mining, 3rd ed. (Kirsch
solution, pillar/tributary-area interaction).
- Hoek, E. (2007), Practical Rock Engineering, Rocscience (open-access course notes; EDZ,
Mohr–Coulomb design).
- Wyllie, D.C. & Mah, C.W., Rock Slope Engineering, 5th ed. (groundwater/vibration effects on
slope stability).
page-1 NOTES
items (1–8), the Additional-Reference-Material section's own numbered Table/Figure captions (e.g. “1. Strength of intact rock material…”, “5. Groundwater…”, “Figure
6…”), and stray numbered lines bled from inside a question's own paragraph. It does not affect the solutions
below, which are worked from the real printed question text (verified against the printed paper pages).
A few words of Question 5 are assumed from context. Page 8's thick-wall-cylinder formula prints “$P_r$” where the algebra requires a tangential stress; the standard thick-wall tangential-stress form is used below. The RMR discontinuity-spacing rating chart on page 12 is not used, because Table 1 (page 9) gives the same information in exact numeric form.
