Sustainable Use of Recycled Waste Plastic Material for Improvement of Granular Column Foundation in Soft Soil–Experimental and Numerical Investigations

The consistent population growth in the urban areas has caused a scarcity of suitable land for infrastructure development. This has challenged engineers to develop innovative techniques for improving the existing ground at the site. The use of granular columns is one such technique that is gaining prominence all over the world for the improvement of soft soils. Recent initiatives around infrastructure development have given impetus to the use of alternative or recycled materials for sustainable and inclusive utilization of resources. This study presents the results of laboratory tests to evaluate the effectiveness of recycled plastic granules used as aggregates in granular columns to improve the load settlement behavior of soft clay foundations. A series of laboratory model tests were performed to evaluate the effect of the undrained shear strength of soil, the length-to-diameter ratio of the granular column, and the geosynthetic encasement. The experimental results show that the vertical load-bearing capacity of the soil bed improved by the granular column and plastic granular column increased by 70–123% and 47–93%, respectively. The use of geosynthetic encasement further enhances the loading capacity of the soil bed with two-fold improvements for the end-bearing column over the floating one. A three-dimensional numerical analysis was done using Plaxis 3D to simulate the experimental conditions, and the results conform well with the model tests. The numerical results validate the bulging failure pattern of the granular column obtained from the experimental trials. The test results affirm the proposed application of recycled plastic granules as an alternative to conventional stone aggregates in granular columns. Kindly check and confirm the edit made in the title.The title has been checked for the aforementioned changes.