Kirsch Fabian - Ground improvement by deep vibratory methods

Ground Improvement by Deep Vibratory Methods

SECOND EDITION

Ground Improvement by Deep Vibratory Methods

SECOND EDITION

Klaus Kirsch

Fabian Kirsch

CRC Press

Taylor & Francis Group

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Boca Raton, FL 33487-2742

2017 by Taylor & Francis Group, LLC

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Printed on acid-free paper

Version Date: 20160531

International Standard Book Number-13: 978-1-4822-5756-4 (Hardback)

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Library of Congress Cataloging-in-Publication Data

Names: Kirsch, Klaus, author. | Kirsch, Fabian, author.

Title: Ground improvement by deep vibratory methods / authors: Klaus Kirsch and Fabian Kirsch.

Description: Second edition. | Boca Raton : Taylor & Francis, CRC Press, 2017. | Includes bibliographical references and index.

Identifiers: LCCN 2016024076 | ISBN 9781482257564 (alk. paper)

Subjects: LCSH: Soil stabilization. | Vibratory compacting. | Foundations.

Classification: LCC TA749 .K57 2017 | DDC 624.1/51363--dc23

LC record available at https://lccn.loc.gov/2016024076

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Contents

Ground improvement by deep vibratory methods continues to be the most used in situ dynamic soil improvement method today, representing well over 10% of all special foundation work. Its versatility in improving the soil conditions in difficult site conditionsbe it in view of the treatment depth, over water, or with restricted head roomand its economical and ecological advantages in comparison with other foundation solutions are recognized and form the basis for further development.

Our publishers proposed this second edition that encompasses the content of the first edition, dealing with a number of corrections and necessary clarifications. In addition, it provides a new on the use of depth vibrators in constructing so-called vibro concrete columns. Although this method improves the soil characteristics only marginally, these small diameter in situ concrete piles are increasingly used for moderately loaded large spread foundations.

All chapters were updated with equipment improvements and have also received new additional case histories highlighting new method applications or special features and advantages. The increasing productivity as a result of the progress made with efficient special plant and effective data acquisition systems has led to a considerable growth of the special foundation market.

In , the partial security concept for slope stability and bearing capacity calculations with stone columns are presented in addition to the conventional safety concept.

, also includes comments on the Carbon Calculator for Foundations, which was published in 2013 by the European Federation of Foundation Contractors and the Deep Foundations Institute, providing a simple and efficient procedure to calculate CO2 emissions of various foundation methods. It is hoped that this tool helps promote those methods that are characterized by high sustainability and low greenhouse gas emissions. Unfortunately, experience tells us that the lowest price of a project is still the decisive factor for the contract award, and as long as the CO2 emissions of construction works are not considered a price worthy item, you should think that the society is prepared to pay the price for a clean environment these considerations remain just an idealistic exercise.

It is nevertheless hoped that this book will help to appreciate not only the economical and technical advantages of ground improvement by deep vibratory methods, but also to recognize their ecological advantages.

This book is written for civil and geotechnical engineers and for the contractors who are engaged in foundation and ground engineering. Students will find this book helpful in their advanced and postgraduate studies.

March 2016

Klaus Kirsch (Retired)

Keller Group plc

Fabian Kirsch

GuD Consult GmbH

The use of depth vibrators for the improvement of soils that are unsuitable as foundations for structures in their original state dates back to more than 70 years. Over the course of time, the deep vibratory methods have become probably the most used dynamic in situ soil improvement methods today. They have not only experienced a continuous development of plant and equipment to carry it out in practice, but also design methods have been proposed and refined to predict the degree of soil improvement that can be achieved.

Today the importance of deep vibratory soil improvement is unrivalled among modern foundation measures; the demand for in situ deep treatment of soils that introduces, if any, only environmentally harmless materials into the ground continues to increase with the rising level of awareness for the environment. Continued development of plant and process controls has resulted in considerable increase in production rates.

When looking at the design concepts in use today, the reader will realize that experience with the system in different soil conditions still plays an important role. Sand compaction, because of the relative simplicity and convincing economy of the system, and the familiar testing methods for the estimation of settlements have probably inhibited the development of theories that would allow the calculation of the improved properties of granular material based upon the fundamentals of soil dynamics. Recent developments show encouraging attempts to correlate the characteristic motion of the depth vibrator working in the ground with the achieved soil properties. The composite system of vibro stone columns and the surrounding cohesive soil has become a challenging field for engineers to apply finite element analyses particularly to the foundation of more complex structures and single foundations. This computational tool supports the designer in his endeavor to find the most economical solution by optimizing the foundation system.