The analysis and prediction of lateral instability in highly stressed, near-surface rock strata

Abstract

The potential for lateral instability of highly stressed, near-surface sedimentary rocks such as the Paleozoic deposits of southern Ontario and western New York State is investigated analytically. The minimum magnitude of the in-situ stress required for a pressure ridge to form is easily computed once values are obtained for the stratum thickness and short-term Young's Modulus, the weight of overburden, and the residual friction with the over- and underlying material. Consideration is also given to the increased likelihood of instability associated with excavations of different widths and depths. Keywords: rock, excavations, quarries, instability, pressure ridges, mechanisms.