Geomechanical Model Study of the Behavior of Underground Openings in Rock Subjected to Static Loads: Report 1. Development of Modeling Techniques

摘要

Model laws governing the design of geomechanical model studies of underground openings in rock subjected to static loads are developed using dimensional analysis and the theory of models. The significant variables influencing the prototype which are considered in this study are free-field stresses, intact rock properties, rock mass discontinuity properties, and the opening geometry. Body forces are considered insignificant as a first approximation. The prototype chosen for study is a short section of a long circular tunnel which is underground at a depth of more than 4 tunnel diameters. The development of a modeling material which successfully models the intact properties of rock is described. The development of an instrumentation system for the model is described. Of particular interest is the development of techniques for imbedding electrical resistance strain gages within the model material to measure radial abd circumferential strains at points within the model around the tunnel. Some tentative observations are made concerning the feasibility of utilizing relatively large scale models to study the behavior of underground openings. (Author)