Abstract:
New metros are being built or existing lines are being extended all over the world. Bauer is involved worldwide in the realization of these projects. For example, Berlin and Munich (Germany), Panama City, Manila (Philippines). In Cairo, Bauer has been involved in the construction of excavation pits since 2008. In Cairo, BAUER is engaged as a subcontractor for a French-Egyptian JV. So far, 17 numbers of excavation pits for various stations, Launching Shafts for the installation of Tunnel Boring Machine (TBM), mutliple Ventilation shafts and cut-and-cover entrances at MetroLine 3 are completed. The excavation levels for the stations are upto 32m below the groundwater table and the required diaphragm walls and soft gel bottoms are upto 86m deep. Soil conditions at given sites are investigated being cultural refill (Stones, concrete) and sand with silt or clay layers.
As stations are located along under existing roads, depending on traffic roads are closed completely or diverted as required. Stations are executed as nearly watertight construction with diaphragm-walls and soft gel plug. After enclosing of a complete box by d-walls, the permeation grouting activities starts. Execution can be separated in two phases: drilling to the required depth and grouting with soft gel having thickness ranging from 4.5 to 12.0m.
The paper discusses the construction challenges and engineering techniques adopted in executing the works of Diaphragm wall shafts upto 100m deep, followed by horizontal drilling and ground freezing to recover the TBM.
Abstract: Theme 1