Deep Excavations in Soil

The book describes the theory and current practices for design of earth lateral support for deep excavations in soil. It addresses basic principles of soil mechanics and explains how these principles are embodied in design methods including hand calculations. It then introduces the use of numerical methods including the fundamental “beam on springs” models, and then more sophisticated computer programmes which can model soil as a continuum in two or three dimensions. Constitutive relationships are introduced that are in use for representing the behaviour of soil including a strain hardening model, and a Cam Clay model including groundwater flow and coupled consolidation. These methods are illustrated by reference to practical applications and case histories from the author’s direct experience, and some of the pitfalls that can occur are discussed. Theory and design are strongly tied to construction practice, with emphasis on monitoring the retaining structures and movement of surrounding ground and structures, in the context of safety and the Observational Method. Examples are presented for conventional “Bottom-up” and “Top-down” sequences, along with hybrid sequences giving tips on how to optimise the design and effect economies of cost and time for construction. It is written for practising geotechnical, civil and structural engineers, and especially for senior and MSc students.

1. Introduction 2. How are deep excavations created 3. Design 4. Contracts 5. Practice

John Endicott is an AECOM Fellow. Since receiving his PhD in modeling slope deformation in 1970 he has have worked on a wide range of Civil Engineering projects. Most of his career has been based in Hong Kong. He was Design Director for the Hong Kong Airport 1240 ha site preparation and other land reclamations, and he has worked on over a hundred underground railway stations and has extensive experience on many, water, road and rail tunnels, basements, foundations, slopes. He pioneered the use of numerical modelling for deep excavations with the first diaphragm wall computer programme for Maunsell in 1976, and the first use of FLAC for a Private Building in Hong Kong in 1986. He is a past Lumb lecturer at University of Hong Kong, and is also an Adjunct Professor running part-time MSc programmes at Hong Kong University of Science and Technology and at University of Hong Kong, and is a Fellow Commoner at St Catharine's College Cambridge.