Behavior of Marine Sand-Clay Mixtures under Static and Cyclic Triaxial Shear

Influence of gradation and proportion of sand on stress–strain behavior of clay–sand mixtures

“…Similar influencing behavior of clay in the soil mixtures containing coarse particles mixed with clay in varying proportions has been reported by other researchers [19][20][21][22][23]. Prakasha and Chandrasekaran [8] reported that inclusion of sand grains in a clay matrix leads to an increase in pore pressure resulting in a decrease in undrained shear strength. Khan et al [15] opined that because of increased material heterogeneity and loss of sand grains from the sides during shearing there was a reduction of strength with an increase in proportion of sand beyond a certain optimum.…”

“…sand) float inside the matrix of fine particles, and hence, the fines dominate the mechanical behavior of the clay-sand mixture, and the coarse grains may or may not contribute to shear resistance as a reinforcing element. The threshold value for the soil mixture to reach this condition depends on the specific mixture, but is usually in the range of 25-45% fines in most cases [8,10,11,15,17,18]. Similar influencing behavior of clay in the soil mixtures containing coarse particles mixed with clay in varying proportions has been reported by other researchers [19][20][21][22][23].…”

“…An exception to this behavior is only kaolinite-sand series, where clay-coarse sand series has shown higher strength when compared to medium and fine sand series. This may be explained based on the observations reported by Prakasha and Chandrasekaran [8], that inclusion of sand grains in a clay matrix leads to an increase in pore pressure resulting in a decrease in undrained shear strength. Probably, in the presence of lesser quantity coarse sand fractions in pure kaolinite clay, the pore pressures developed may be less compared that of medium sand and fine sand.…”

“…To meet the various practical applications of soils, a need was felt for proper understanding of the interactions of clay and coarse fractions like sand or gravel present in the soil, and hence research focus changed from ideal soils to clay-sand mixtures. In this direction, many researchers have reported the findings of the interactions of clay-granular matrix and their influence on the engineering behaviour depending on the proportion of each component (sand/gravel or clay being present in the soil [8][9][10] to name a few). A review of the literature indicates that though various attempts have been made by various researchers to understand the interactions of granular aggregates with clay for different engineering applications like slope stability [9], for understanding the stability of foundations for offshore oil platforms and jack up rigs [8], for understanding of earth quake liquefaction [11] and the like, in most of the studies reported in the literature the focus was mainly on understanding the relative proportions of the clay and granular fractions on the strength behaviour without considering their gradation effect.…”

Behaviour of normally consolidated clay containing isolated solid inclusions

“…Holtz and Willard, 1956;Muir-Wood and Kumar, 2000;Vallejo and Mawby, 2000;Ni et.al. 2004;Jafari and Shafiee, 2004;Prakasha and Chandrasekaran, 2005;Long and Menkiti, 2007;Cabalar and Hasan, 2013;Ruggeri et.al. 2016).…”