Influence of loading area on subsoil deformation moduli and structure settlements : Mazurkiewicz, B K Ground Engng, V10, N5, July 1977, P13–16

Abstract

When constructing a dry dock it is sometimes necessary, because of its dimensions and the geological and hydrogeological conditions, to carry out a number of tests to obtain the best available data for use in determining settlements of the dock for the different stages of loading. The construction adopted for the dry dock took the form of a concrete slab founded directly on the subsoil and connected rigidly to the side walls. To reduce possible stresses rising from unequal settlements and to elminate the influence of shrinkage, placing of the concrete was divided into two stages. To determine the input data for the calculations of the dry dock structure, a large number of test borings was carried out. The most important layer to be taken into consideration in determining the settlements of the structure was the layer of stiff silty varved clays. Loading tests were carried out covering all the basic layers--sandy, clayey and gravel strata. Taking into consideration the moduli of deformation obtained from the loading tests, the calculations of settlements of the structure were performed by the stress method. Measurements of the dry dock settlements in the initial period of its operation showed the existence of elastic deformations of the subsoil, the magnitude of which depended on the actual state of the dry dock loading. Further measurements were made over a period of six years and indicated no increase of the permanent settlements of the subsoil. Also, the interaction between the structure and subsoil during the dock's construction period and the period of action of the installation for the hydrostatic lift reduction, caused a stabilization of the subsoil sufficient for the safe operation of the dry dock.