“…In the past, the stress-dilatancy relationship was broadly examined by many researchers, including Matsuoka [19], Tatsuoka [28], [29], Cornforth [6], Bolton [2], De Josselin de Jong [9], Coop [3], Cuccovillo and Coop [8], Coop and Wilson [4], Wanatowski [33], and others [1], [11], [14], [30], [31]. Cotecchia and Chandler [7] showed that the stress-dilatancy relationship for triaxial compression tests is different for drained and undrained conditions; this phenomenon has not been investigated until now.…”