Utilization of Rice Husk Ash for Mitigating Settlement and Excess Pore Water Pressure in Black Cotton Soil: A Plaxis 2D Analysis

This study investigates the use of rice husk ash (RHA) as a sustainable ground improvement technique to address settlement and excess pore water pressure in black cotton soil using Plaxis 2D, focusing on a standard embankment model. Black cotton soil, with its expansive behavior and poor load-bearing capacity, often poses significant challenges in geotechnical engineering, especially under loading conditions where swelling and high pore pressures are prevalent. RHA, characterized by its low porosity, was selected to improve these challenging soil properties due to its eco-friendly nature and effectiveness as a stabilizer. The results from laboratory unconfined compressive strength (UCS) tests showed that the addition of RHA enhanced the soil’s cohesion values, indicating a significant improvement in soil strength. These laboratory cohesion values were incorporated into the Plaxis 2D analysis. The simulation revealed that the inclusion of RHA reduced settlement by 80% and lowered excess pore water pressure by 56%, based on the pore pressure distribution in the embankment model. The improved cohesion led to an increase in soil stiffness, enhancing its load-bearing capacity and reducing deformation under load. By reducing both the settlement and excess pore pressure, RHA provided a viable solution for improving the performance of BCS. The use of RHA not only addresses the problematic swelling behavior but also promotes sustainability by utilizing agricultural waste. This study demonstrates the practical application of RHA in enhancing soil stability, particularly for embankment constructions and similar geotechnical applications.