Soil exploration in a 500 m deep fjord, Western Norway

Abstract

Abstract A number of engineering organizations and individuals have contributed toward a comprehensive feasibility study made in 1973–1974 in connection with a submerged floating tunnel project in Norway. The tunnel is planned to cross the 500 m deep Eidfjord in Hardanger over a length of about 1.3 km. The main findings from geophysical explorations, subsoil sampling operations, and an extensive laboratory testing program on extracted soil samples are described here. A main part of this paper is devoted to the study of a full‐scale field test with a gravity anchor block weighing 180 tonne. This study reports on the behavior of the block during launching from its sloping construction ground, the sinking operation, and the behavior of the block after it reached the bottom at 450 m depth. Observations of settlement and tilt are available, and a comparison is made between the observed and computed behavior. Broadly speaking, a fairly good agreement was found.