In Situ Strain Measurement around Shaft in Sedimentary Rock and its Numerical Analysis

Abstract

The main purpose of this study is to make clear the variation of strain induced by the excavation of a shaft with a diameter of 6m and a depth of 150m. Variation of strain around the shaft was measured using 8-element borehole guages embeded before excavation, and a numerical analysis was conducted for comparison with the results of in situ strain measurement.
The following conclusions were obtained:
(1) Strain variation around shaft is induced by the extraction force acting on the wall of the opening.
(2) Variation of strain in sedimentary rock with wide to moderately spaced joints can be simulated by the FEM analysis using an elastic model.