 If it had originally been in a very loose state, then contraction may occur before the shearing begins or in conjunction with the shearing.Sometimes, testing of cohesive samples is done with no confining pressure, in an unconfined compression test.This requires much simpler and less expensive apparatus and sample preparation, though the applicability is limited to samples that the sides won't crumble when exposed, and the confining stress being lower than the in-situ stress gives results which may be overly conservative.