Behavior of Lined Openings in Jointed and Unjointed Model Rock Masses.

摘要

The objective of this investigation was to study experimentally the behavior of horizontally oriented,steel-lined cylindrical openings in jointed and unjointed model rock masses subjected to static surface overpressures. The results of six model tests are presented and discussed herein. Three of the tests were conducted on virgin jointed model rock masses containing steel-lined cylindrical openings. The other three tests were repeated loadings of an unjointed model rock mass containing a steel-lined opening. The boundary conditions were approximately plane stress conditions in all cases. The development of jointed model rock masses and the required instrumentation are also described herein. The behavior of the steel liners was measured with circumferential strain gages and diametric extensometers. The free-field response was measured with SE-type stress gages. Test results indicated that even widely spaced joints drastically influence the moments and diametrical movements of the tunnel liner,but that the thrust is not so grossly affected. (Author)