Productivity analysis for Boulac's wastewater microtunnels in Egypt

The need for utility service line replacement or repairs with minimum disruption to the surface has increased the demand for trenchless excavation methods like microtunneling. Microtunneling is a trenchless technique that is used in installation of new pipelines. Microtunneling can be applied in gravity and pressure lines, permanent ducts for cables, and crossings under rails or roads. In order to give a better view of the microtunneling method, a successful case study of a microtunneling project is presented. This project was one of the projects to construct a new sewer system supplementary to the old sewer system in Cairo, Egypt. Boulac is a very crowded district of Cairo, Egypt, with about 4 million people. The contractor was a consortium of five specialized international companies. The engineer was a consortium of four American and British companies. Boulac's microtunneling project value was about $300 million and lasted for about 5 years. The length of microtunneling drives in Boulac was about 6.0 km. Microtunneling machines of 600 and 1,000 mm diameters were used. The productivity of the machines has been analyzed including consideration of factors such as the operator's experience in different soils for different microtunneling machines.