Effect of temperature variation on a rock salt deformation – a case study

Abstract

In situ deformation measurements using extensometers installed in bedded rock salt at 650 m below the surface at the Waste Isolation Pilot Plant (WIPP) were analysed extensively. The strain rate curves varied periodically suggesting that seasonal temperature variation affects the deformational behaviour of the underground excavations. The effect of different parameters including opening's geometry, stand-up time, and distance from the opening on the strain rate changes due to a temperature variation were investigated with a new approach using a curve-fitting equation. For understanding the measured deformational behaviour of the underground excavations at WIPP, a temperature analysis was carried out using the Heating 7.2 program. The actual temperature variation with time in the rock mass around the underground excavation could be successfully simulated with the program.