DYNAMIC-RESPONSE OF AN OPENING IN JOINTED ROCK

A large-scale test was performed on a 0.4 m diameter lined cylindrical opening in a 2 m cube of jointed limestone for the purpose of gatheri ng data to develop and validate computational models for the dynamic r esponse of structures in jointed rock, The limestone cube was assemble d from over four thousand 51 mm square x 0.6 to 1.2 m long limestone b ricks and was then embedded in a concrete test bed and loaded explosiv ely with a 100 MPa, cylindrically diverging stress,cave. The material velocity around the boundary of the jointed limestone cube was measure d with accelerometers and these data were used to generate a continuou s velocity boundary condition that can be used for computational simul ations, Additional instrumentation measured stress in the limestone, j oint slip and deformation of the opening. After the test, the limeston e cube was recovered and carefully disassembled to reveal fracture pat terns in the limestone bricks. Vertical fractures emanating from the s pringlines formed a chimney of bricks that slipped measurably relative to the rest of the rock mass above the opening and to a lesser degree below the opening. (C) 1998 Elsevier Science Ltd. All rights reserved .