Waikiki Public Bath Force Main Replacement Project consists of 1,037 m of 400 mm force main that carries the wastewater from the Public Bath pump station to a gravity sewer on the Kuhio Avenue. This force main transports wastewater underneath Kalakaua Ave, very close to some of the most expensive real state in the world. This area is the heart of Waikiki beach, and it is full of beach resorts, five star hotels, shopping, etc. The soil strata can be described as 2.50 to 3.00 m deep of beach sand on top of half a meter of a very hard coral ledge on top of a lagoon deposit layer (very soft gray fat clay). The NSPT values in this lagoon deposit layer range from zero to eight. The specified construction method for this project was microtunneling of 700 mm of Permalok steel casing with a 400 mm PVC carrier pipe inside the casing. The annular space between the two pipes was grouted with low density grout. Many problems were encountered during the construction phase of this project. This paper is a retrospective review of the project from the contractor’s point of view. It covers the design and construction aspects of this project in addition to the encountered problems and the lessons learned from that project.
Atalah, Alan, "Case History of Microtunneling through a Very Soft Soil Condition" (2013). Construction Management Faculty Publications. 4.
International Journal of Economics and Management Engineering