Geomechanical Model Study of the Behavior of Underground Openings in Rock Subjected to Static Loads. Report 2. Tests on Unlined Openings in Intack Rock.
ILLINOIS UNIV URBANA DEPT OF CIVIL ENGINEERING
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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 design and development of a loading apparatus which allows independent control of the three principal stresses on the block 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 sandplaster material to measure radial and circumferential strains at points within the model around the tunnel. Model behavior observed was analysed and compared to theoretical predictions and field observations. Author
- Geology, Geochemistry and Mineralogy
- Civil Engineering