Fabrication of a small-scale laminar shear box and low-cost data acquisition system to determine dynamic properties of soil

Geotechnical earthquake engineering requires a comprehensive understanding of soil-structure interaction response to seismic activity. Shaking table and centrifuge tests using rigid and flexible soil box are carried out for physical modeling experiments to understand the soil-structure interaction response to seismic activity. In this study, a laminar shear box of 720 mm in length, 390 mm in width, and 720 mm in height was designed using 15 horizontal laminas of aluminum C-section for a small shake table instrument. The soil bed acceleration and nonlinearity were measured using a newly designed low-cost data acquisition (DAQ) system developed using the Arduino Uno board and the ADXL345 accelerometer sensor. The serial peripheral interface (SPI) protocol was utilized to collect output data from DAQ for data transfer. The calibration of the laminar shear box for boundary effect, inertia effect, and soil densification was determined for the flawless working of the box. Stress-strain behavior, acceleration, damping ratio, and strain-dependent modulus, such dynamic response parameters of the soil bed, are being studied. During the shaking table test, considerable strain and subsequent inelasticity are observed. Increased excitation energy in soil reduces shear modulus, and flatter loops indicate more nonlinearity and a higher damping ratio, meaning increased energy dissipation. The laminar shear box integrated with the developed DAQ system demonstrated reliable performance in recording soil response data and analyzing dynamic soil properties, providing insights into soil-structure interactions. The findings offer a cost-effective solution for dynamic soil testing, crucial for understanding soil behavior during earthquakes and other dynamic events and improving engineering practices.