Rock Pressurization: A Method for Stress Control in Underground Structures.
Oudenhoven MS; Vandergrift TL
Proc Int'l Symp on Unique Underground Structures Csm Press 1990 :76-1to76-13
Active stress control is an important technique not currently used in the design of underground structures. Current opening designs leave overburden stresses to be redistributed around the opening naturally. Stress concentrations then occur near the opening surface, where there is minimal confinement. Structural stability would be improved if stress control methods could be developed to concentrate the overburden stresses deeper in the wall rock, where confinement gives the rock added strength. The U.S. Bureau of Mines compared active and passive stress control methods for their potential to control the redistribution of underground stress. Rock pressurization, an active method, is shown to have a greater potential for stress control than destressing, a passive method. Computer results from a rock pressurization model show that the tangential stress on an opening surface can be reduced by an order of magnitude when stress is redistributed to a stiffened zone away from the opening. Creating stiffened zones around an opening to form a pressure arch would both shield the opening from the field stress and take advantage of the confined rock strength.
Proc. Int'l Symp. on Unique Underground Structures; Csm Press, 1990, PP. 76-1 to 76-13