Controlling the safety of geotechnical structures: a proposed approach

Summary

This paper considers the safety of geotechnical structures using various design philosophies which include the global safety method and a number of limit state design methods. The methods are considered individually and their treatment of uncertainties of design briefly discussed in terms of parameter and system uncertainty. Each method is not designed to produce a definitive measure of safety, but should be viewed as an aid in the process of controlling or managing safety. Crucial to all design methods is the idea of a design parameter. However, in certain instances it is often not clear whether a design parameter should be an upper or lower bound on its possible value. A proposed limit state design method for overcoming this problem is outlined, based on putting bounds on parameters. An example of a reinforced concrete cantilever retaining wall is used to demonstrate its advantages over current methods. The proposed method offers a more rational approach to the design of retaining structures.