Experimental Investigation of Small Scale Lined and Unlined Cylindrical Cavities in Rock-Like Materials.
Abstract
The behavior of rock-like model structures simulating lined and unlined tunnels was determined experimentally by use of strain and displacement gages. Primary interest was in the response of the composite rock-liner structure rather than the interaction between the two elements. Tests were made of two liner thicknesses of two different Young's moduli in plane stress and plane strain. The liner had little effect until certain values of thickness, stiffness, and strength were obtained. Theoretically, thick, stiff liners should prevent tension at the top and bottom of the tunnel, but this condition was difficult to obtain experimentally. Major problems solved were the design of rock-like materials and embedment of strain gages. Early tensile failure caused deviation of strain readings from the theoretical elastic solution depending upon the gage position. Other gages registered approximate theoretical values after initial fracture. Initial fracture and consequent alteration of stress and strain distribution resulted in an overall response which approaches that of natural rock. Models tested in the centrifuge responded in a similar manner, although the gage readings were less consistent. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1970
- Accession Number
- AD0877724
Entities
People
- Charles J. Haas
- George B. Clark