Publication Abstract

Proceedings - Fourth International Conference - Piling and Deep Foundations, 1991, Stresa, Italy, (DFI)

The Effect of Wall Stiffness on Bending Moments
D.M. Potts & R.A. Day Imperical College of Science, Technology & Medicine, University of London, UK

Many deep excavations in urban areas are currently being constructed using stiff concrete diaphragm or secant pile walls. Research has shown that as wall flexibility increases the stress imposed by the soil redistribute and reduce the structural forces in the wall. Unfortunately this beneficial effect is accompanied by greater wall and soil movements. In this paper the results of numerical analyses are used to quantify these effects. Three typical excavations in stiff clay are analyzed. For each case, analysis using a range of wall stiffness from a Frodingham 1N to a 1m thich concrete wall have been performed. Large reductions in maximum bending moment occurs as the flexibility is increased and this is accompanied by increased wall and soil movements. The magnitude of the increased movement depends on the number of propping levels. It is concluded that in many situations a flexible sheet pile wall solution can be both viable and more economical.

 article #503; publication #37 (IC-1991-IT)