Differences between the Geotechnical Campaigns at Front-End Engineering Design (FEED) and Detailed Design—A Case Study

This paper presents a case study of the geotechnical conditions encountered within a project at Saudi Arabia at both the Front-End Engineering Design (FEED) and Detailed Design geotechnical campaigns. The soil formations were considerably varied between the two investigations resulted in extensive ground improvement activities that have not been anticipated within the FEED stage. The overall objectives of such study are to explore the soil formations found, and to evaluate/summarize the soil treatment measures necessary for each of the two different campaigns in order for the project specifications in relation to settlement, bearing capacity, and liquefaction potential to be achieved. Moreover, the potential factors that may have affected the differences on the strength/density of the soils within the two different geotechnical campaigns that have been carried out at nearby locations are also explored. Based on the analysis conducted, it is concluded that soil strength on the FEED data ismuch higher compared to the strength on the Detailed Design soil data resulted on shifting the soil mitigation measures from light to severe, hence, leading to project both excessive cost and considerable increase on time schedule.