Compaction risk assessment of excavation, construction and demolition waste for land reclamation, Malta

Abstract

Land reclamation, an essential process in the development of urban areas and infrastructure projects, often necessitates the use of fill material to increase land area and elevate terrain. In the past two decades, Malta has been utilising excavation, construction, and demolition waste as fill material due to the abundant amount of waste generated as a result of the construction and infrastructure boom. However, the successful application of excavation, construction and demolition waste for land reclamation relies on effective compaction techniques to ensure the stability and long-term performance of the reclaimed land. This research investigates the main compaction risks encountered in utilising excavation, construction and demolition waste as fill material for land reclamation at sea or on land, in Malta. It aims to address critical knowledge gaps and provide a comprehensive understanding of the compaction process, potential risks, and mitigation strategies. The research employs a multidisciplinary approach, integrating geotechnical engineering principles, and construction management practices. The literature review, encompasses the properties and characteristics of excavation construction and demolition waste generated locally, land reclamation developments in Malta, existing compaction techniques, and risk management. Subsequently, the methodology used was a qualitative technique by means of semi-structured interviews, done with experts in this field. This enabled to fill literature gaps and extracting key thematic components, followed by a thematic analysis that served as a foundational step in identifying relevant compaction risks. The findings of this dissertation provided two valuable insights. Firstly, it provided a clear picture of the process that this type of waste undergoes to ensure that it is adequate for the land reclamation project and suitable for compaction. Secondly, this research identified the compaction risks that are mostly encountered and offered practical recommendations to mitigate these risks. The research concludes that the most important factors to achieve a well-compacted fill are; characterisation of material, analysis of the underlying material, and lastly have good quality control, quality assurance and a multidisciplinary team to mitigate the obtained compaction risks.