Using the Eq. (1), the limiting silt content of this studied sand and silt mixtures was calculated 30%.
Figure 20a and b shows excess pore water pressure response of sand silt mixtures of pre-consolidation relative density 78%.
Zone 4 (i.e., silt mixtures: clayey silt to silty clay), zone 5 (sand mixtures: silty sand to sandy silt), zone 6 (sands: clean sand to silty sand), and zone 8 (very stiff sand to clayey sand), with some scattered data points are located in zone 9 (very stiff, fine grained).
Zone 4 (i.e., silt mixtures: clayey silt to silty clay), zone 5 (sand mixtures: silty sand to sandy silt), zone 6 (sands: clean sand to silty sand), and zone 8 (very stiff sand to clayey sand), with some scattered data points are located in the zone 9 (very stiff, fine-grained).
As it can be observed from the figure that, the soil profile principally encompasses zone 4 (i.e., silt mixtures: clayey silt to silty clay), zone 5 (sand mixtures: silty sand to sandy silt), zone 6 (sands: clean sand to silty sand), and zone 8 (very stiff sand to clayey sand), with some scattered data points located in zone 9 (very stiff, fine-grained).
Table 1 Description of zones in Robertson's soil classification chart (after [29]) Zone Soil description 1 Sensitive, fine grained 2 Organic soils (peats) 3 Clays (clay to silty clay) 4 Silt mixtures (clayey silt to silty clay) 5 Sand mixtures (silty sand to sandy silt) 6 Sands (clean sand to silty sand) 7 Gravelly sand to sand 8 Very stiff sand to clayey sand 9 Very stiff, fine grained.
Furthermore, based on the extended mathematical model, the relationship between the maximum and the minimum void ratios of a sand-silt mixture can be derived.
The validity of the derived linear relationship between the maximum and the minimum void ratios of a sand-silt mixture is also verified by the measured results from experiments.
This study shows that the variation of maximum void ratio with respect to fines content of a sand-silt mixture is caused by the same mechanisms that influence the variation of minimum void ratio.
Open image in new window Fig. 25 Effect of silt content on undrained monotonic peak shear strength of sand-silt mixture at relative density of 30, 60 and 78% Open image in new window Fig. 26 Variation of dry density with silt content at constant relative density.
After the sand-silt mixtures are frozen at −5 °C, the direct shear tests are conducted.
