Grouting Methods in Manhole Rehabilitations at Coastal Areas: Case Study

Abstract

For underground structures at coastal areas, inflow/infiltration (I/I) control is a critical procedure to guarantee their quality, especially for manholes, which are more likely to have structural problems and I/I problems. There are several methods that could address these problems, including spraying, grouting, and in situ lining. In this case study, a combined grouting method is proposed for a deep-buried double-walled manhole rehabilitation project, the Diyar Al Muharraq (DAM) project in Bahrain. This case study involves I/I investigation, rehabilitation design, construction management, and evaluation of rehabilitation according to the monitoring data. The 4-step grouting method shows an excellent rehabilitation performance, the monitoring data show that the water level in manholes lowered by 21.35%, and the brine pressure at the bottom of manholes decreased by 78.26%, which means the combined grouting method is effective for manhole rehabilitation at coastal areas.