Ground improvement concept and selection for an onshore gas supply facilities in Malaysia

Abstract

An onshore natural gas supply facility is proposed to be constructed in Bintulu, Sarawak to meet the local industrial demand. The project site is mostly flat, with compressible layer identified at several locations. To mitigate the risk of uneven settlement, RC piled foundation is selected to support facilities on the soft ground. However, for infrastructure such as roads, drains, and underground firewater lines, fully piled foundations will drastically increase the project duration and cost. Alternative mitigation measures to address the issues shall not hinder the access for other activities and construction sequence. In this paper, the approach taken to mitigate site-specific subsurface conditions is explained. Readers will be guided through the stages of ground improvement, from the inception of the project, the methodology used, analysis conducted, assessment and the way forward. Several options were explored considering factors such as estimated consolidation period, depth and rate of settlement, and stability analysis etc. The Remove and Replace, was selected as most suitable solution. Preliminary field results show that the targeted settlement at some areas were achieved earlier than anticipated. This enable the field installations such as firewater pipe to be laid earlier, contributed to the good project progress. Monitoring program is continued to ensure all identified areas met the accepted criteria.