GEOCISA has extensive experience in the use of hydromills for diaphragm wall construction. It was one of the pioneering companies in Spain to work with hydromill rigs, and has been using the technique since 1992, taking on ever-more ambitious projects. Over the years our workforce has acquired a wealth of expertise, meeting every challenge. At present, we hold the Spanish record for depth in reinforced concrete diaphragm wall construction, having built a 71-metre deep diaphragm wall at the Collbanc station on Line 9 of the Barcelona Metro.
Hydromill technology is very clean, as the bentonite slurry is always pumped through a closed circuit, even when extracting the cuttings from panel excavation. The suspended solids are extracted using desanders, and once dry are transported for disposal. GEOCISA always incorporates a high-capacity filter press to treat the bentonite slurry waste, since large volumes are produced, particularly in clayey ground. The filter press separates the slurry into dry waste and water. The dry waste is dry enough to be transported to any inert waste disposal site; and the water can be reused or, once the pH has been corrected to comply with local authority regulations, can be disposed of directly into any nearby drainage system.