Constructing structures on very soft soils poses significant geotechnical challenges, including bearing capacity failure, and excessive settlement due to the soil’s low shear strength and high compressibility. This case study outlines a comprehensive ground improvement strategy for the IOCL storage terminal proposed in North Chennai, addressing the site’s very soft soils with cone resistance (qc) ~ 0.2 MPa recorded up to 4–10 m depth. Higher settlements estimated after the vibro stone column installation necessitate the use of preloading technique to meet the stringent service stage settlement requirement of 100 mm. This combined solution serves as an alternative to pile foundations, aiming to achieve optimal ground improvement and fulfil the project’s performance criteria. The study includes a detailed analysis of site-specific geotechnical parameters, design considerations, and construction sequences tailored to address the unique challenges posed by the very soft soils. Additionally, settlements observed during preloading activities are compared with design-stage estimates to assess the actual ground behaviour for predicting the settlement due to future loads. Emphasizing sustainability and cost-effectiveness, the study’s findings provide practical insights into integrating vibro stone columns and preloading for reliable ground improvement in challenging geotechnical environments within the stipulated timeline.