The Stress and the Earth Pressure Phenomena in the Rocks around Shaft Bottom Spaces

Abstract

In general, shaft bottom spaces in mines are large and of complex shape, and are the most important places for haulage and winding. Though it is essential to clear up the earth pressure phenomena around these spaces in order to plan rational linings, very few investigations have been carried out into this problem. The authors have, therefore, studied the stress and the earth pressure phenomena around shaft bottom spaces by means of barodynamics and three dimensional photoelastic experiments. In the latter experiments, special consideration has been given to the treatment of statically indeterminate stresses. It is found, from this study, that if the rock is not sufficiently strong, failure takes place on the roof, especially at the part of the roof between a shaft and a horizontal level, due to tensile stress, and in a few cases on the side walls due to compressive stress ; that the degree of stress concentration is not so high as expected ; and that these failures do not progress further once the corners of rock have been rounded off. Furthermore, there is a discussion of how to line the shaft bottom spaces.