Ground Modification Methods Reference Manual – Volume I NOTICE
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U.S. Department of Transportation Publication No. FHWA-NHI-16-027 Federal Highway Administration FHWA GEC 013 April 2017 NHI Course No. 132034 Ground Modification Methods Reference Manual – Volume I NOTICE The contents of this document reflect the views of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect policy of the Department of Transportation. This document does not constitute a standard, specification, or regulation. The United States Government does not endorse products or manufacturers. Trade or manufacturer’s names appear herein only because they are considered essential to the objective of this document. COVER PHOTO CREDITS Upper left: Massachusetts Department of Transportation Upper middle: MixOnSite USA, Inc. Upper right: Bob Lukas, Ground Engineering Consultants, Inc. Lower left: Menard Group USA Lower middle: Subsurface Constructors Lower right: Hayward Baker Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FHWA-NHI-16-027 4. Title and Subtitle 5. Report Date GEOTECHNICAL ENGINEERING CIRCULAR NO. 13 December 2016 GROUND MODIFICATION METHODS - REFERENCE MANUAL 6. Performing Organization Code VOLUME I 7. Author(s) 8. Performing Organization Report No. Vernon R. Schaefer, Ryan R. Berg, James G. Collin, Barry R. Christopher, Jerome A. DiMaggio, George M. Filz, Donald A. Bruce, and Dinesh Ayala 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Ryan R. Berg & Associates, Inc. 2190 Leyland Alcove 11. Contract or Grant No. Woodbury, MN 55125 DTFH61-11-D-00049/0009 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered National Highway Institute U.S. Department of Transportation 14. Sponsoring Agency Code Federal Highway Administration, Washington, DC 20590 15. Supplementary Notes FHWA COTR: Heather Shelsta FHWA Technical Working Group Leader: Barry Siel, PE; Silas Nichols, PE; Scott Anderson, PhD, PE; and Brian Lawrence, PE. Contractor Technical Consultants: Jie Han, PhD, PE This manual is the updated version of FHWA NHI-06-019/20, prepared by Ryan R. Berg & Associates, Inc.; authored by V. Elias, J. Welsh, J. Warren, R. Lukas, J. Collin, and R. Berg; FHWA Technical Consultants J. DiMaggio and S. Nichols. 16. Abstract This FHWA Geotechnical Engineering Circular No. 13 provides guidance on Ground Modification Methods, and also serves as the reference manual for FHWA NHI courses No. 132034, 132034A, and 132034B on Ground Modification Methods. The purpose of this manual is to introduce available ground modification methods and applications to design generalists, design specialists, construction engineers, and specification and contracting specialists involved with projects having problematic site conditions. An introductory chapter provides a description, history, functions, and categories of ground modification. A description of the web-based GeoTechTools (http://www.geotechtools.org) technology selection guidance system and geotechnology catalog is also provided in the first chapter. The introductory chapter is followed by stand-alone technical category chapters. Each category chapter includes a broad introduction to the technical category including typical applications, a listing of common technologies used in the U.S., and summaries for specific technologies in the category. Each technology summary includes: description; advantages and limitations; applicability; complementary technologies; construction methods and materials; photographs; design guidance; quality assurance methods; costs; specifications; and reference list. Each technical category and the technology summaries therein reflect current practice in design, construction, contracting methods, and quality procedures. This publication was prepared with the practicing transportation specialist in mind and with the benefit of extensive industry review. 17. Key Words compaction, deep and mass soil mixing, 18. Distribution Statement dynamic column supported embankments, grouting, lightweight fills, pavement subgrade stabilization, No restrictions. reinforced soil structures, stone columns, vertical drains, vibro-compaction 19. Security Classification (of this report) 20. Security Classification (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 386 Form DOT F 1700.7 Reproduction of completed page authorized SI* (MODERN METRIC) CONVERSION FACTORS APPROXIMATE CONVERSIONS TO SI UNITS Symbol When You Know Multiply By To Find Symbol LENGTH in inches 25.4 millimeters mm ft feet 0.305 meters m yd yards 0.914 meters m mi miles 1.61 kilometers km AREA in2 square inches 645.2 square millimeters mm2 ft2 square feet 0.093 square meters m2 yd2 square yard 0.836 square meters m2 ac acres 0.405 hectares ha mi2 square miles 2.59 square kilometers km2 VOLUME fl oz fluid ounces 29.57 milliliters mL gal gallons 3.785 liters L ft3 cubic feet 0.028 cubic meters m3 yd3 cubic yards 0.765 cubic meters m3 NOTE: volumes greater than 1000 L shall be shown in m3 MASS oz ounces 28.35 grams g lb pounds 0.454 kilograms kg T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t") TEMPERATURE (exact degrees) oF Fahrenheit 5 (F-32)/9 Celsius oC or (F-32)/1.8 ILLUMINATION fc foot-candles 10.76 lux lx fl foot-Lamberts 3.426 candela/m2 cd/m2 FORCE and PRESSURE or STRESS lbf poundforce 4.45 newtons N lbf/in2 poundforce per square inch 6.89 kilopascals kPa APPROXIMATE CONVERSIONS FROM SI UNITS Symbol When You Know Multiply By To Find Symbol LENGTH mm millimeters 0.039 inches in m meters 3.28 feet ft m meters 1.09 yards yd km kilometers 0.621 miles mi AREA mm2 square millimeters 0.0016 square inches in2 m2 square meters 10.764 square feet ft2 m2 square meters 1.195 square yards yd2 ha hectares 2.47 acres ac km2 square kilometers 0.386 square miles mi2 VOLUME mL milliliters 0.034 fluid ounces fl oz L liters 0.264 gallons gal m3 cubic meters 35.314 cubic feet ft3 m3 cubic meters 1.307 cubic yards yd3 MASS g grams 0.035 ounces oz kg kilograms 2.202 pounds lb Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T TEMPERATURE (exact degrees) oC Celsius 1.8C+32 Fahrenheit oF ILLUMINATION lx lux 0.0929 foot-candles fc cd/m2 candela/m2 0.2919 foot-Lamberts fl FORCE and PRESSURE or STRESS N newtons 0.225 poundforce lbf kPa kilopascals 0.145 poundforce per square inch lbf/in2 * SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 2003) PREFACE One of the major tasks within geotechnical engineering is to design, implement and evaluate ground modification schemes for infrastructure projects. During the last forty years significant new technologies and methods have been developed and implemented to assist the geotechnical specialist in providing cost-effective solutions for construction on marginal or difficult sites. The impetus for ground modification has been both the increasing need to use marginal sites for new construction purposes and to mitigate risk of failure or of poor performance. During the past several decades, ground modification has come of age and reached a high level of acceptance in the geotechnical community. Its use is now routinely considered on most projects where poor or unstable soils are encountered. From the geotechnical engineer's point of view, ground modification means the modification of one or more of the relevant design engineering properties (e.g., increase in soil shear strength, reduction of soil compressibility, and reduction of soil permeability) – or the transfer of load to more competent support layers. From the contractor’s point of view, ground modification may mean a reduction in construction time and/or a reduction in construction costs. Both points of view are valid reasons to consider the use of ground modification techniques and are often mutually inclusive. Herein, ground modification is defined as the alteration of site foundation conditions or project earth structures to provide better performance under design and/or operational loading conditions. Ground modification objectives can be achieved using a large variety of geotechnical construction methods or technologies that alter and improve poor ground conditions where traditional over-excavation and replacement is not feasible for environmental, technical or economic reasons. Ground modification has one or more of the following primary functions, to: • increase shear strength and bearing resistance, • increase density, • decrease permeability, • control deformations (settlement, heave, distortions), • improve drainage, • accelerate consolidation, • decrease imposed loads, • provide lateral stability, I-i • increase resistance to liquefaction, and/or • transfer embankment loads to more competent subsurface layers. The purpose of GEC 13 is to introduce available ground modification methods and applications to design generalists (i.e., project planners, roadway designers, consultant reviewers, etc.), design specialists (i.e., geotechnical, structural, pavement, etc.), construction engineers, specification writers, and contracting specialists involved with projects having problematic site conditions. This publication was prepared with practicing transportation specialists and generalists in mind. The introductory chapter provides a description, history, functions, and categories of ground modification. Additionally, the role of ground modification in addressing project risks and constraints and risk mitigation,