DESIGN OF RETAINING WALLS EMBEDDED IN STIFF CLAY

Abstract

This report covers the design of signly propped or cantilever walls embedded in stiff overconsolidated clay. It is applicable to a wide range of soils in Britain and overseas. The structural form considered is that installed by the diaphragm wall technique or equivalent process, or by the driving of sheet piles. An introduction to simple earth pressure theory relevant to stiff clays is given, and the selection of appropriate design soil parameters is discussed, with particular reference to laboratory tests. Formulae and charts are presented for use in calculating lateral earth pressures, and the important influence of water pressures is described. Special considerations which apply to temporary works design are also discussed. Various methods of assessing the factor of safety against overall stability are compared, and four of these are recommended. Each method is illustrated by worked examples. Appropriate values of factor of safety are given in each case. Several alternatives for calculating working loads on the wall are discussed. Some practical aspects of wall construction influencing design are highlighted, and current areas of uncertainty are identified. (Author/TRRL)