GUIDELINES FOR CONSTRUCTING NATURAL GAS AND LIQUID HYDROCARBON PIPELINES THROUGH AREAS PRONE TO LANDSLIDE AND SUBSIDENCE HAZARDS FINAL REPORT Prepared for the Design, Materials, and Construction Committee of Pipeline Research Council International, Inc. Prepared by: C-CORE D.G. Honegger Consulting SSD, Inc. January 2009 This report is furnished to the Pipeline Research Council International, Inc. (PRCI) as a final deliverable for PRCI project ENV-1, “Pipeline Integrity Management for Geohazards.” The report is the product of tasks carried out by ENV-1 Contractors; C-CORE, D.G. Honegger Consulting, and SSD, Inc. The contents of this report are published as received from the Contractors. The opinions, findings, and conclusions expressed in the report are those of the authors and not necessarily those of PRCI, its member companies, or their representatives. Publication and dissemination of this report by PRCI should not be considered an endorsement by PRCI or the Contractors, or the accuracy or validity of any opinions, findings, or conclusions expressed herein. The material presented in this guideline has been prepared in accordance with the standard of care for technical engineering reports. The recommendations and processes in this guideline should not be adopted without first securing competent advice with respect to the suitability for a specific application. In publishing this report, PRCI makes no warranty or representation, expressed or implied, with respect to the accuracy, completeness, usefulness, or fitness for purpose of the information contained herein, or that the use of any information, method, process, or apparatus disclosed in this report may not infringe on privately owned rights. PRCI assumes no liability with respect to the use of, or for damages resulting from the use of, any information, method, process, or apparatus disclosed in this report. The text of this publication, or any part thereof, may not be reproduced or transmitted in any form by any means, electronic or mechanical, including photocopying, recording, storage in an information retrieval system, or otherwise, without the prior written approval of PRCI.” Acknowledgements This report was prepared for PRCI as a deliverable under a project with the U.S. Department of Transportation Pipeline Hazardous Materials Safety Administration (PHMSA). In addition to the contributions by the three contractors, C-CORE, D.G. Honegger Consulting, and SSD, Inc., this report benefited from the contributions of several individuals and organizations. The most significant contribution was provided by Rex L. Baum, Devin L. Galloway, and Edwin L. Harp at the U.S Geological Survey (USGS). Under a cooperative research and development agreement, the USGS provided a summary of the state-of-practice on landslide and subsidence hazard identification and published their summary as Open-File Report 2008-1164. Much of the material in this document related to hazard definition was extracted from the USGS Open-File Report. Dr. James Merritt, the PHMSA Organization Program Coordinator for this project, participated in the initial project meetings and provided suggestions that assisted in defining level of detail and areas of emphasis for this document. D.G. Honegger Consulting was responsible preparation of this report, with input from C- CORE and SSD, Inc., for review by the other PRCI Contractors on this project. This effort was assisted by the suggestions and input provided by the following individuals with expertise in geotechnical engineering, landslide hazard evaluation and risk assessment, pipeline geohazards risk assessment, and techniques and methods for general monitoring of pipeline alignments and location-specific landslide monitoring: Mr. Raymond Boivin, Plateau Engineering Ltd. Mr. Richard Butler, Golder Associates Ltd. Mr. Moness Rizkalla, Visitless Integrity Assessment Ltd. An ad hoc steering group for this project was established by PRCI. This steering group provided technical review and PRCI approval of the final report. Members of the ad hoc steering group are provided below: Richard Gailing, Steering Group Chair Scott Baumgardner Southern California Gas Company Marathon Pipe Line LLC Roger Bergman Guillaume L’Henoret Chevron Texaco E&P Technology Company Gaz de France Dave Katz Joe Zhou Williams Companies TransCanada PipeLines Ltd. The project is indebted to the following individuals contracted to serve as expert reviewers during the development of these guidelines. Their comments and suggestions were valuable in refining the content and organization of these guidelines. Dr. Jeffrey R. Keaton, MACTEC Engineering and Consulting, Inc. Mr. Mark E. Schmoll, URS Corporation i Table of Contents 1.0 INTRODUCTION TO THE GUIDELINES ............................................................. 1 1.1 Scope ............................................................................................................... 2 1.2 Problem Statement........................................................................................... 2 1.3 OVERVIEW OF PROCESS ................................................................................. 3 1.3.1 Defining Performance Requirements ........................................................... 3 1.3.2 Overview of Landslide Hazards Assessment and Mitigation........................ 9 1.3.3 Overview of Subsidence Hazards Assessment and Mitigation................... 15 2.0 LANDSLIDE HAZARD........................................................................................ 17 2.1 Regional Landslide Hazard Analysis .............................................................. 17 2.1.2 Qualitative Methods of Analysis ................................................................. 20 2.1.3 Quantitative Methods of Analysis ............................................................... 21 2.1.4 Shallow Landslide Analyses....................................................................... 25 2.1.5 Deep-Seated Landslide Analyses .............................................................. 26 2.1.6 Advantages and Disadvantages of the Various Susceptibility or Hazard Assessment Methods .................................................................... 27 2.2 Engineering Geologic Mapping and Related Field Studies............................. 29 2.2.1 Small-Scale Mapping ................................................................................. 30 2.2.2 Large-Scale Mapping ................................................................................. 32 2.3 Landslide History ............................................................................................ 35 2.4 Landslide Movement Rates ............................................................................ 35 2.5 Methods of Estimating Displacement.............................................................. 37 2.5.1 Estimating Total Displacement................................................................... 37 2.5.2 Prediction of Time to Failure ...................................................................... 38 2.5.3 Movement thresholds................................................................................. 39 2.5.4 Note on Effects of Seismic Events ............................................................. 39 2.6 Methods of Stability, Stress, and Deformation Analysis.................................. 40 2.6.1 Limit Equilibrium Analysis........................................................................... 40 2.6.2 Continuum Stress and Deformation Analysis ............................................. 44 2.7 Cautions Regarding Slope Stability Analyses................................................. 46 2.8 Data Requirements......................................................................................... 48 2.9 Challenges, Dilemmas and Reliability............................................................. 48 ii 2.9.1 Cost............................................................................................................ 50 2.9.2 Reliability.................................................................................................... 51 2.10 Subsurface Exploration................................................................................... 52 2.10.1 Sampling .................................................................................................... 58 2.10.2 Testing ....................................................................................................... 59 3.0 SUBSIDENCE HAZARD .................................................................................... 61 3.1 Recognition..................................................................................................... 64 3.1.1 Known Subsidence Areas .......................................................................... 65 3.1.2 Identifying Subsidence Susceptible Areas ................................................. 72 3.2 Measurement, Mapping and Monitoring ......................................................... 76 3.3 Analysis and Simulation.................................................................................. 78 3.3.1 Fluid Withdrawal......................................................................................... 78 3.3.2 Mining......................................................................................................... 78 3.3.3 Hydrocompaction ....................................................................................... 79 3.3.4 Thawing Permafrost ..................................................................................