Model to forecast risk in variation of geological and hydrological stratum in the expressway

Abstract

Expressway construction projects are susceptible to risks stemming from geological and hydrological variations along their routes, necessitating careful budgetary planning. Most of these unforeseen risks are encountered in the below the ground formation of the road base level. Especially in the existing ground geological and hydrological factors are varying along the road trace, causing this risk to become more complex and unforeseen nature. This research endeavors to address these challenges by developing a model for forecasting risks associated with geological and hydrological changes along expressway routes in Sri Lanka. Through a mixed-method approach comprising literature reviews, expert interviews, questionnaire surveys, and case studies, this study systematically investigates the identification, ranking, and analysis of risk factors. The research identified sixteen main geotechnical and hydrological risk factors through literature review and expert interviews. These factors were subsequently condensed into ten significant risk factors and further analyzed through questionnaire surveys. Expert evaluations were employed to assess the impact and frequency of occurrence of these risk factors, leading to the identification of two primary risk factors with the most severe impact on project cost overruns. Furthermore, a Risk Forecasting Model was developed based on case study data, allowing for the estimation of risk amounts during the preliminary estimation phase of future expressway projects. The model, validated against survey findings, aims to provide decision- makers with invaluable insights for budgetary allocations and risk management strategies. The findings of this research underscore the importance of proactive risk assessment and forecasting in expressway construction projects, offering a systematic approach to mitigate financial pressures and ensure project success.