Over the last 20 years or so, I have witnessed and grown to appreciate the difficulty undergraduate students sometimes have in grasping geotechnical courses. Geotechnical courses have many new concepts and indigestible expressions to initially be memorized. The expressions, which generally originate from advanced elastic mechanics, plastic mechanics, and numerical approaches, are technical and not easily accessible to students.
To resolve the problem, our research resolution has been to minimize the number of methods and input parameters for each method and to resolve as many problems as possible. We believe this will allow easier access to learning, practice, and integration into further research. Piles, as a popular foundation type, are frequently used to transfer superstructure load into subsoil and stiff-bearing layer and to transfer impact of surcharge owing to soil movement and/or lateral force into underlying layers. .
They are conventionally made of steel, concrete, timber, and synthetic materials (Fleming et al. 2009) and have been used since the Neolithic Age (6,000~7,000 years ago) (Shi et al. 2006). Their use is rather extensive and diverse. For instance, in 2006, ~50 million piles were installed in China, ranging (in sequence of high to low proportion) from steel pipe piles, bored cast-in-place piles, hand-dug piles, precast reinforced concrete piles, pre-stressed concrete pipe piles, and driven cast-in-place piles to squeezed branch piles.
It is critical that any method of design should allow reliable design parameters to be gained in a cost-effective manner. More parameters often mean more difficulty in warranting a verified and expeditious design. We attempt to devise design methods that require fewer parameters but resolve more problems. This has yielded a systematic approach to model pile response in the context of load transfer models. This is summarized in this book of 13 chapters.
Chapter 2 provides a succinct summary of typical methods for estimating bearing capacity (including negative skin friction) of single piles and pile groups. Chapter 3 recaptures pile–soil interaction models under vertical, lateral, or torsional loading. Chapters 4 and 5 model the response of vertically loaded piles under static and cyclic loading and time-dependent behavior, respectively. The model is developed to estimate settlement of large pile groups in Chapter 6. A variational approach is employed to deduce an elastic model of lateral piles in Chapter 7, incorporating typical base and head constraints.
The pu-based model is further developed to mimic a nonlinear response of laterally loaded pile groups (see Chapter 11) and to design passive piles in Chapter 12. The mechanism about passive piles is revealed in Chapter 13 using 1-g model tests. Overall, Chapter 3 provides a time-dependent load transfer model that captures pile–soil interaction under vertical loading in Chapters 4 through 6.
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