Silty Essay

MODEL PARAMETERS
The silty sand used in this study was processed by mixing 40% quarry dust into the fine sand. The fine sand is collected from Cherthala, Kerala and quarry dust is procured from Blue Diamond M-sand manufacturers, Kattangal, Kerala. For preparing the soil combination, the ingredients were put into a container and mixed thoroughly to have a homogeneous soil mix until there was no noticeable colour difference and segregation. All the basic properties tests were performed on the soil combinations, and the properties are listed in Tables 1. A combined dry sieve and hydrometer analysis was carried out to obtain the particle size distribution. The gradation curve is shown in figure 1. Relative density tests were performed as per the

The limited eight numbers of hypoplastic model parameters (φc, hs, n, ei0, ed0, ec0, β and α) are determined based on the detailed procedure for the determination of model parameters explained by Herle and Gudehus (1999).
Critical State Friction Angle
The critical friction angle φc can be obtained from the angle of repose of dry granular material from cone pluviation tests. If the portion of grains with diameter < 0.1 mm is too large, conventional shear tests are recommended for determination of φc. Hence, for the present study, direct shear box tests were conducted on loose soil at different consolidation pressures to determine the critical friction angle φc. A series of direct shear box tests were conducted on silty sand samples of loosest and densest possible conditions at different consolidation pressures. The critical friction angle of each sample is determined from the slope of linear failure envelope in loosest possible state and is found to be 330.

Minimum, maximum and critical void ratios at zero pressure