ABSTRACT
The paper describes the stress-strain behaviour of micaceous sands. The presence of sand-size mica plates within a sand increases its void ratio, modifies its volume change characteristics and introduces a collapse potential. The effects depend on the quantity, distribution and orientation of the mica. The effect of the size of mica on the stress-strain response of granular mixes containing coarser and fine grains of mica was also derived from laboratory studies on a uniform and a well graded sand. It is shown that for the same size of mica the response of the host sand can be altered completely (i.e. from dilatant to contractant) due to the presence of mica, depending on the grading of the host sand. The effects of the mica can be appreciated if the packing in a clean sand and a sand with mica is compared. The test results imply that the importance of shape and location of additives in sand is not reflected in measures such as void ratio or granular void ratio.
