Excerpts

Preface The United States produces about 300 million tons of solid waste per year. Up to 75 percent of the solid waste continues to be landfilled--in spite of vigorous efforts aimed at waste reduction, recycling, and re-use. A modern, well-constructed landfill can be characterized as an engineered structure that consists primarily of a composite liner, leachate collection and removal system, gas collection and control system, and final cover. A landfill also behaves as a giant in-situ bioreactor whose contents undergo complex biochemical reactions. The production of landfill gas is a major byproduct of waste decomposition processes. The adoption of suitable design and construction methods is essential not only to reduce design and construction costs, but also to minimize long term operation, maintenance, and monitoring expenses. Geotechnical Aspects of Landfill Design and Construction addresses landfill siting, design, and construction issues in a comprehensive manner. The characteristics of landfill containment envelopes and their design/construction are treated in detail. The attributes and advantages of composite liners relative to conventional compacted clay liners are examined carefully. The book discusses both the material properties and engineering design of geosynthetic components (e.g., geomembranes, geotextiles, geocomposites, and geosynthetic clay liners) that are used in modern landfill construction. Methods of estimating landfill leachate quantities and gas generation in addition to the design of leachate and gas collection systems are also described in detail. We include other important topics as well--such as vertical expansion and bioreactor concepts--that are ways of increasing capacity at existing landfills. Several chapters in the book are devoted to the measurement and determination of landfill performance. These performance considerations include settlement estimates, mass stability, liner leakage rates (by both hydraulic convection and chemical diffusion), envelope durability, leachate and gas collection, and drainage efficiency. Final cover design to limit rainfall infiltration, frost problems, and erosion is addressed as well. Geotechnical Aspects of Landfill Design and Construction focuses on actual design and construction procedures, as opposed to a discussion of solid waste management issues and to general descriptions and/or conceptual designs. We present the reader with a complete, integrated package of analytical tools, design equations, and construction procedures for all elements of a landfill. The purpose of the book is to show the reader how to design and construct a real landfill step by step. To this end, we provide in the book not only design equations, but also specific guidelines and procedures, and calculation examples for constructing various elements of a modern landfill. Since landfill design and construction in the United States uses English Computational units almost exclusively (and there is no end in sight of this practice), we have complied by using these units as primary. Worldwide, however, SI units are the norm and we have accompanied the U.S. units with SI computational units in parentheses. The conversion to SI units is "soft." The notable exception to this is hydraulic conductivity where we have used in the traditional metric unit of "cm/sec." Geotechnical Aspects of Landfill Design and Construction is intended as (i) a reference book for practicing professionals, (ii) an agency training manual, and (iii) university textbook. A draft manuscript of the book has been used and tested by the principal author in a geoenvironmental graduate course at the University of Michigan since 1995. Carefully selected design examples, diagrams, and tables are incorporated into the book. These give the reader a better sense of the necessary site investigation, planning, analysis, and organization that go into a landfill design and construction project. In addition to worked design examples we have also included homework problems and an extensive reference list at the end of every chapter. The authors wish to express their appreciation to the following individuals for their encouragement and support throughout the preparation of the manuscript: Professors Richard D. Woods and E. Benjamin Wylie, University of Michigan; and Jim J. Sygo, Kenneth J. Burda, Delores M. Montgomery, and Elizabeth M. Browne, Michigan Department of Environmental Quality. The authors also would like to acknowledge and thank the following individuals for sharing their knowledge and ideas during the course of many discussions about the book: Stephen R. Blayer, V Wesley Sherman, Jr., and Carolyn B. Parker, Michigan Department of Environmental Quality; Dr. Gary R. Schmertmann, Geosyntec Consultants; Dr. Te-Yang Soong, Earth Tech, Inc.; Dr. Jengwa Lyang, NTH Consultants, Ltd.; and Scott R Lockhart, Hull and Associates, Inc. XUEDE (DAN) QIAN ROBERT M. KOERNER DONALD H. GRAY Excerpted from Geotechnical Aspects of Landfill Design and Construction by Xuede Qian, Donald H. Gray, Robert M. Koerner All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.