Ontwikkeling en onderzoek ten behoeve van tunnelfundatie door middel van onderstromen

Abstract

During the preliminary investigations ordered by the Rijkswaterstaat for the crossing of the river Westerscheldt in the southern part of the Netherlands, the sand-flow-system for the foundation of a sunken tunnel was developed. Preformed openings in the bottom of the tunnel elements are connected at predetermined intervals to a central pipeline inside the tunnel, and a mixture of sand/water is then simply forced to flow under the temporarily supported and adjusted elements. In this manner a dense layer of sand is regularly built up underneath the tunnel irrespective of the weather conditions and the depth of the tunnel, without obstruction to shipping. The entire operation can be controlled from a central point in or outside the tunnel; this method is also suitable for the foundation of caissons in harbours or at sea. The article describes the system and the model tests, and gives figures for the upward forces and the quality of the sandlayer