ABSTRACT:

Hollow cylinder tests are intended to simulate borehole failure, under controllable and downscaled conditions. Upscaling from laboratory conditions to field conditions is not trivial, however. The finite size of the hollow cylinder and the downscaled hole diameter have impacts on the stress level and the borehole strength that have to be accounted for. Furthermore, the downscaled hole size also requires scaling of the loading rates in order to properly match pore pressure distribution and stress distribution. It is not possible for a hollow cylinder test to fully reproduce field conditions with respect to stress path, and in most cases not the stress geometry either. An additional complication is that borehole failure is not unambiguously defined in the field nor even in the laboratory test. These complications imply that upscaling of results from the HC test requires a relevant theoretical model, or at least careful design of the test. Nevertheless, the test is valuable for calibration of borehole stability models under specific conditions.

1. INTRODUCTION
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