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Preface
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Deep excavation is a crucial phase in the construction of superstructures and under-ground transportation system. In the congested urban area, the construction of braced excavation needs to ensure not only the stability of excavation itself, but also the integrity and serviceability of surrounding buildings. It has become the mainstream of deep braced excavation to design and construct with inspection of the induced deformation.
Incautious deep braced excavation can induce excessive soil displacement and consequent subsidence or uneven settlement of ground facilities behind the wall.Such deformation problems and control measures have been widely reported. The discussions of abundant completed projects can provide engineers guidance to raise more reliable designs and appropriate schemes for deep excavations. For deep exca-vations in soft soils, the matters of poor design and the consequent large defor-mation problem still exist due to the incomprehensible understanding of the soils' natural mechanical properties. Empirical observations or simulations using numer-ical methods such as finite-element or finite-difference procedures have been widely adopted to present excavation-induced displacement prediction. However, the design of deep excavation as well as the earth retaining system should comprise of the use of different methods such as the empirical methods, the observational approaches, the numerical simulation, the probabilistic and inverse analysis, the case report, and failure case analysis.
This book covers the scopes and methods mentioned above, including the basic flow chart for excavation design and construction; the basal heave stability check;estimation of excavation responses including the retaining wall deflection, ground surface settlement, as well as the strut forces; the reliability analysis and back anal-ysis; effect of excavation on adjacent infrastructures and some protection measures;
failure case reports; and causal analysis. It tries to cope with design practice, implemented via the recent publications from the authors in reputable journals.
This book comprises eleven chapters. Chapter 1 overviews the relevant topics.
Chapter 2 provides the overall stability analysis, in which the strength reduction technique was adopted for the calculation of factor of safety against basal heave.
Chapter 3 presents the determination of the lateral earth pressure as well as the strut forces. Chapters 4 and 5 focus on the estimation ofthe retaining wall defiection andthe ground surface settlements, respectively. Chapter 6 gives probabilistic analysis on excavation responses while Chap. 7 performs the analysis about one-strut failure, which directly triggers the Nicoll Highway collapse in Singapore and Xianghu Metro Station collapse in Hangzhou. Chapter 8 focuses on the jet grouting slabs and jet grouting piles as ground improvements for the control of ground deforma-tion. Chapter 9 shows the protection of adjacent infrastructures. Chapter 10 provides the case reports and back analysis while Chapter 11 summarizes some excavation failures worldwide.
I am pleased to witness the publication of this book and hope that the authors would bring us more findings in deep excavation and earth retaining system design when they reprint it.