Rock pressure calculation for rocky and disperse soils

Abstract

The paper discusses the classical problem of determining rock pressure on a mine working support. In this problem, the authors differentiate two cases – rock pressure in rocky soils and rock pressure in dispersed soils. This division is due to the significant differences observed in the rocky and dispersed soils in their ultimate states. In particular, while the strength of dispersed soils can be described by the Coulomb line, for rocky soils the envelope of the Mohr circles has a pronounced nonlinear character. It was found as a result of calculations that there exist three supporting schemes for any soil depending on the width of excavation: self-restraining arch (or ceiling), pressure arch, and caving column. The paper introduces the concept of two critical spans of a mine working that differentiates the said schemes. A hypothesis has been proposed and verified that the process of rock pressure formation is quite similar to that for active pressure on retaining structures.