Dynamic Behaviour Analysis of Barak River Sand Using Resonant Column Apparatus

The whole of the northeast region of India lies in the seismic zone V. Barak river flows through the Silchar town of Assam. Several construction projects associate themselves with the sand extracted from the Barak River for carrying out their operations; hence, its dynamic analysis becomes important. This study aims at analyzing the dynamic behaviour of Barak river sand in dry conditions by varying influencing parameters such as confining pressure and relative density, at a very low strain condition. The most important parameters in the dynamic analysis of soil include Shear modulus (G) and damping ratio (D), which are evaluated using resonant column apparatus in the torsional mode of vibration. The sand samples are prepared by compacting to relative densities of 30%, 50% and 65% and tested at confining pressures of 50, 100 and 200 kPa. From the results, it can be observed that with an increase in strain percentage, the shear modulus of the sand being tested decreased, but the damping ratio values increased. Shear modulus values obtained are found to be proportional to confining pressure and relative density, but the damping ratio decreased.