Slope Stability Reference Guide

2y ago
37 Views
3 Downloads
8.94 MB
338 Pages
Last View : 21d ago
Last Download : 6m ago
Upload by : Mya Leung
Transcription

United StatesDepartment ofAgricultureForest ServiceEngineerlng StaffSlope Stability Reference Guidefor National Forestsin the United StatesWashington, DCVolume IAugust 1994

While reasonable efforts have been made to assure the accuracy of this publication, in no event will theauthors, the editors, or the USDA Forest Service be liable for direct, indirect, incidental, or consequentialdamages resulting from any defect in, or the use or misuse of, this publications.Cover Photo Ca tion:EYESEE DEBRIS SLIDE, Klamath National Forest, Region 5, Yreka, CAThe photo shows the toe of a massive earth flow which is part of a large landslide complex that occupies about onesquare mile on the west side of the Klamath River, four air miles NNW of the community of Somes Bar, California. Theactive debris slide is a classic example of a natural slope failure occurring where an inner gorge cuts the toe of a largeslumplearthflow complex. This photo point is located at milepost 9.63 on California State Highway 96.Photo by Gordon Keller, Plumas National Forest, Quincy, CA.The United States Department of Agriculture (USDA) prohibits discrimination in its programs on the basis of race, color,national origin, sex, religion, age, disability, political beliefs and marital or familial status. (Not all prohibited basesapply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact the USDA M i c e of Communications at 202-720-5881(voice) or202-720-7808(TDD).To file a complaint, write the Secretary of Agriculture, U.S. Department of Agriculture. Washington, D.C. 20250 or call202-720-7327(voice) or 202-720-1127(TDD). USDA is an equal employment opportunity employer.

United StatesDepartment ofAgricultureForest ServiceEngineering StaffSlope Stability Reference Guidefor National Forestsin the United StatesVolume IAugust 1994Coordinators:Rodney W. PrellwitzThomas E. KolerJohn E. StewardEditors:David E. HallMichael T. LongMichael D. Remboldt

Dedication to Rod PrellwitzCourtrtey Cloyd, Engineering Geologist, Siuslaw National ForestThe rugged terrain of America's national forests presents engineering geologists andgeotechnical engineers with many challenges. Small budgets and staffs encourageinnovative exploration techniques, while high design standards are necessary forcompliance with Federal resource protection regulations. These sometimesconflicting conditions have fostered the development of skilled professionals, whooften rely on the experiences of their colleagues for help with difficult problems. Inthis spirit of cooperation the Slope Stability Reference Guide was developed, a spiritthat characterizes the career of the guide's instigator, Rod Prellwitz. In recognitionof his years of guidance and support as a mentor and friend to geotechnicalspecialists in the Northwest, we dedicate these volumes, a summary of what we havelearned together.Rod Prellwitz's career as a geotechnical engineer is the result of his love of themountains and forests of the West and his love for the process of solvinggeotechnical problems. The symboIs of these two loves are his continuingenthusiasm for field work and the license plate on his four-wheel-drive pickup,GEOTECH.Rod's professional training began in 1957 arthe Montana Schoo) o r n i n e s (nowMontana College of MineraI Sciences and Technology), where h'e &died geologicalengineering with a petroleum option. After graduating in 1961' he,worked for 3years as a seismic geophysicist in Wyoming, Utah, and olor o Gith Texaco, Inc.During that time he realized that career advancement in the petroleum industry meantspending long periods of time in such "God-forsaken places" as Houston, Tulsa, andDenver-a depressing prospect for a young man who loved the big, empty country ofthe West.In 1964, Rod heard that the USDA Forest Service was looking for a civil engineeron the Apache National Forest, and soon he was on his way to Springerville,Arizona, leaving the oil business behind forever. In 1965, he moved on to a positionin preconstruction engineering in the regional office at Missoula, Montana, seizing achance to return to the State he had grown to love. By 1966, he had moved on toHamilton, Montana, and the Bitterroot National Forest, where he eventually becamean assistant forest engineer. Rod later found that he was spending far too much timemanaging the motor pool and not enough time on engineering; so, in 1969 hetransferred to the Northern Region Materials Investigation Unit back in Missoula as ageotechnical engineer.His role as a regional office geotechnical engineer gave him an opportunity to seemuch of Idaho and Montana and a full range of geotechnicd problems. Rod tookgraduate courses at the University of Idaho in the early 1970's, graduating with anDedicationiii

M S . in civil engineering with a geotechnical option in 1975. In 1979, he became aresearch geotechnical engineer at the Intermountain Research Station in Missoula,continuing there until his retirement in early 1993.Slope stability analysis and ground water monitoring have been Rod's primaryprofessional interests as a researcher. Since 1975, he has written more than a dozenprofessional papers, made numerous presentations before professional societies ongeotechnical topics, and developed several practical guides and handbooks for use byForest Service field specialists. Among his papers "SSMOS-Slope StabilityAnalysis by Three Methods of Slices with the HP-41 Programmable Calculator in1985 and "SSIS and "SSCHKS-Preliminary Slope Stability Analysis with theHP-41 Programmable Calculator in 1988 were instantly popular with Forest Servicegeotechnical engineers and engineering geologists in the Northern and PacificNorthwest Regions.Through the development of those publications, the Pacific Southwest and PacificNorthwest Region geotechnical specialists learned what their Northern Regioncolleagues had known for some years: Rod was a research scientist who understoodthe field conditions they faced every day, and he was interested in helping them findthe answers to their technical problems. He routinely provided technical support tonational forest engineers, geologists, and soil scientists who were trying to applytextbook soil mechanics and ground water principles to steep forested terrainconditions and finding that the two were not always compatible.Rod is probably best known in the Forest Service for developing what is commonlycalled the three-level slope stability analysis concept. The three-level system grewout of his understanding that engineering geologists and geotechnical engineers couldcontribute their knowledge of soil mechanics and physical processes to forestplanning and decision making. His 1983 presentation to the Transportation ResearchBoard 62nd Annual Meeting, Landslide Analysis Concepts for Management of ForestLands on Residual and Colluvial Soils (T.R. Howard and W.D. Wilson, co-authors),summarizes the three-level system and sets the stage for his later work on Level IStability Analysis (LISA), Stability Analysis for Road Access (SARA, the level I1program), and XSTABL (the level 111 program). LISA and XSTABL have becomestandard analysis tools for resource planning level and site-specific slope stabilityassessments, respectively, on national forests in the westem United States.As helpful as these tools have been, Rod's willingness to teach others what he haslearned is his greatest contribution to the profession. He has always been more thangenerous with his time when people ask for help, prefening a field trip to look at theproblem to talking about it on the phone. His informal style and ever-present sketchpad frequently turn simple questions into impromptu tutoring sessions, where gainingknowledge and understanding are as important as finding the answer to the problem.Over the years, Rod has been a frequent contributor to technical workshops held bythe Forest Service, the Oregon and Washington Departments of Transportation, andthe Federal Highway Administration. In the last 5 years, he has been a principalinstructor at more than half a dozen Forest Service-sponsored workshops focused onthe LISA computer model, demonstrating his belief that technical information is mosteffectively exchanged through discussion and shared experience.Even though we won't see the familiar Montana GEOTECH license plates as oftenin our office parking lots, Rod has left us a rich legacy of his knowledge andDedication

experience and a promise to be available occasionally for a look at an interestingproblem. In thanks for his many gifts, we dedicate the Slope Stabiliry ReferenceGuide to Rod Prellwitz.Dedication

AcknowledgmentsThe authors, editors, and coordinators thank the following individuals for their reviewefforts and comments that helped to make this publication more user-friendly--quiteoften sparing the authors some embarrassment. We especially acknowledge Dr.Robert L. Schuster of the US. Geological Survey and Peter Jones of the Rogue RiverNational Forest for their extremely detailed reviews. In addition to the internalreview by the authors themselves, the following group of professionals made atremendous contribution:Matt Brunengo, Washington Department of Natural ResourcesTom DeRoo, Mt. Hood National ForestCarol Hammond, Shannon and WilsonRichard Kennedy, Bridger-Teton National ForestAllen King, Plumas National ForestDavid Knott, GAI AssociatesMargaret McHugh, Gifford Pinchot National ForestJim McKean, USFS Pacific Southwest RegionDan Miller, University of WashingtonStan Miller, University of IdahoKen Neal, Neal and AssociatesAnn O'Leary, Naval Facilities CommandBill Powell, USFS Pacific Northwest RegionBruce Vandre, USFS Intermountain RegionRichard Watanabe, Oregon Department of TransportationChester F. ("Skip") Watts, Radford University.AcknowledgmentsviiL

AbstractSlope stability studies in the USDA Forest Service have been conducted successfullyin accordance with a three-level concept.Level ILevel I, the most general, is conducted for watershed analyses, ecosystemmanagement support, and timber sale area planning. Level I slope stability studiesinclude reviews of air photo coverage and geologic and geotechnical reports; a briefreconnaissance to verify slope processes and to map soil and rock units andlandforms; and development of geomorphic zones based on slope form, soil and rockcharacteristics, and geologic processes. Each geomorphic zone is assigned soil androck units for analysis and evaluation for potential failure due to natural processesand forest management activities. The LISA (Level I Stability Analysis) and DLISA(Deterministic Level I Stability Analysis) programs are often used in the process.Level IILevel 11, an intermediate level used for evaluation of slope stability along roadcorridors and other route studies, consists of the office elements of a level I study, areconnaissance (including sketches of slope characteristics of each alternativetransportation corridor), and defining geomorphic and road design segments based onslope, rock, soil, and drainage characteristics and geologic processes. These analysesare often completed using slope stability charts and the DSARA (DeterministicStability Analysis for Road Access) slope stability program. The probabalistic SARA(Stability Analysis for Road Access) program is still under development.Level IllLevel 111, the most detailed (site-specific) level, is intended for design of stabilizationmeasures. In addition to the elements identified under level I1 for the transportationroute evaluation, the level I11 study includes measurement of field-developed crosssections and installation of site-specific monitoring instrumentation, as appropriate.Level 111 analyses are often completed using the XSTABL (method of slices)interactive program for soil and the Federal Highway Administration's rock slopestability analysis method for rock slopes.In addition to the three-level method, this guide discusses the forest planning process,geomorphology, channel processes and sediment budgets, climatology, soil and rockmechanics, hydrogeology, exploration and testing methods, and risk analysis as theyapply to slope stability. The guide also contains sample problems for analysis,remediation design, and specifications for construction.Abstract

Table of ContentsPageVOLUME I.Dedication to Rod Prellwitz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii.Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .viiAbstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ix.Section I . Introduction and Suggestions for Use1A GuidetotheGuide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.1B Introduction to the Three-Level Stability Analysis Concept . . . . . . . . . . . . . . . . . . . . . . . .9.References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Section 2. Initial Slope Stability Assessment in Resource Planning2A2B2C2D2E2FIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.Climatic. Geologic. and Hydrologic Influences on Slope Stability . . . . . . . . . . . . . . . . . . . 39Basin-Scale Assessment of Geologic Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47Considerations for Rock Slope Stability in Reconnaissance-Level Projects . . . . . . . . . . . . . 53Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55Watershed Analysis Case Histories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77.Section 3. Site Investigation3A3B3C3D3EProblem Definition and Application of the Scientific Method . . . . . . . . . . . . . . . . . . . . . 131Soil and Rock Classification for Engineering Analysis and Design . . . . . . . . . . . . . . . . . 135Surface Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139.Subsurface Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177.Geotechnical Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201.References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205.Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1Section 4. Parameters for Stability Analysis4A484C4D4E4FFundamental Stress-Strain Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .331Soil WeightNolume Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .345.Strength and Behavior of Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .377.Strength and Behavior of Rock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427Ground Water Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477.Root Strength and Tree Surcharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .543.References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .551Table of Contents

Table of Contents (continued)PageSection 5. Slope Stabil@ Analysis.5A Fundamentals and Derivations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .563I Analysis-Natural Slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .583.5C Soil Slopes-Level 11 Analysis onstructedSlopes . . . . . . . . . . . . . . . . . . . . . . . . . . 5955D Soil Slopes-Transition From Deterministic to Probabilistic Analyses . . . . . . . . . . . . . . . .633.5E Soil Slopes-Level I and I1 Probabilistic Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643.SF Soil Slopes-Level I11 Stability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6455G Soil SlopesSample Problem Including All Three Levels of Analysis . . . . . . . . . . . . . . .663.5H Rock Slopes-Fundamentals and Sample Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683.References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 723.Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15B Soil Slopes-LevelVOLUME III.Section 6 n Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .733.Modification of Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737.Surface and Subsurface Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .767.Horizontal Drains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783.Buttresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803.Soil Slope Stabilization-Reinforced Fills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 817Shear Trenches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 841.Rock Slope Stabilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .851Comparison of Alternatives and Decision Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .861.Construction Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 897Post-Construction Monitoring of the Technical Structures and Projects . . . . . . . . . . . . . . .913.References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 927Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1.Table of Contents

SECTION 1INTRODUCTION AND SUGGESTIONS FOR USEPrincipal contributors:Joe Bailey, Engineering Geologist (Section Leader)USDA Forest ServiceRegional Office EngineeringP.O. Box 3623Portland, OR 97208Tom Koler, Research Engineering GeologistUSDA Forest ServiceIntermountain Research Station1221 S. MainMoscow, ID 83843Ken Neal, Engineering GeologistKenneth Neal & Associates2014 Baker TerraceOlympia, WA 98501Rod Prellwitz, Geotechnical EngineerUSDA Forest ServiceIntermountain Research Station1221 S. MainMoscow, ID 83843

Page1A GuidetotheGuide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.lA.l Purpose of the Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1A.2 Contents and Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.1A.3 Suggested Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.1A.3.1 Land Managers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.1A.3.2 GeologistslEngineering Geologists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71A.3.3 Geotechnical Engineers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.1A.3.4 Non-Geotechnical Specialists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1B Introduction to the Three-Level Stability Analysis Concept . . . . . . . . . . . . . . . . . . . . . . . .9lB.l Role of Analysis in the Decision-Making Process . . . . . . . . . . . . . . . . . . . . . . . . . 9.1B.2 Land Management Decisions Requiring Stability Input . . . . . . . . . . . . . . . . . . . . . .91B.2.1 Level I: Resource Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1B.2.2 Level 11: Project Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111B.2.3 Level 111: Site Stabilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111B.3 Stability Analysis Applicable at the Three Levels . . . . . . . . . . . . . . . . . . . . . . . . . 111B.3.1 Level I: Infinite Slope Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121B.3.2 Level 11: Stability Number Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . .121B.3.3 Level 111: Method of Slices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Appendix1.1 Introduction to the Three-Level Stability Analysis Concept-Chestershireand Backdrop Timber Sales: Case Histories of the Practice of EngineeringGeology in the Olympic National Forest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

1A. Guide to the GuideDaniel Joe Bailey, Regional Engineering Geologist, Pacijc Northwest RegionThomas E. Koler, Research Engineering Geologist, Intermountain Research Station1A.1 Purposeof the GuideAll geotechnical specialists experience, at some time in their careers, the problem ofhow to provide an appropriate, accurate, understandable answer to a question posedby a land manager or project engineer. The specialist realizes that the managerprobably has little knowledge of the scientific complexity involved in answering aseemingly simple geotechnical question. Of several legitimate answers, which is"correct"? The anxiety level rises if a geotechnical mentor is not readily available toguide the specialist through the process of providing the correct answer. Of severalpossible ways to begin gathering and analyzing data, which is the most valid? Themost cost effective? The most truly useful? We have all gone through thisexperience, and continue to do so. Therefore, we have compiled this slope stabilityreference guide to help us and those who work with us to better understand howgeotechnical specialists get work done. We have included real-world examples ofcommon geotechnical problems, along with the reasons behind, and the methods of,the investigative techniques employed. The purpose of this guide is to provide apractical document that geologists and engineers can use in their work. We hope thatyour copy will become tattered and dog-eared as you use it to provide these answers.1A.2 ContentsandOrganizationThis guide can be viewed either as a textbook describing concepts and theories or asa laboratory workbook with practical problems. Each section contains both theoryand practical examples; we strongly recommend that both be understood and used.A knowledge of the theory behind the methods employed in a particular examplehelps you to recognize the differences between that example and your specific realworld problem. However, knowing the theories will not help much unless yourecognize which are relevant to your particular problem.Section 1 contains the introduction to the guide and an introduction to the three-levelstability analysis concept.Section 2 discusses the role of stability analysis in cumulative effects analysis andempirical analysis of an area.Sections 3 and 4 describe the concepts central to the analysis of slope stabilityaffecting both natural and constructed slopes.Sections 5 and 6 give detailed presentations on application of the three-level systemto typical field problems. Section 5 emphasizes analysis of slope stability, whilesection 6 emphasizes methods of stabilization.

Figure lA.l is an idealized three-level slope. stability analysis flowchart. This chartwill appear in the introduction to each section with the area of analysis discussed inthat section highlighted.LEVEL IllANALYSISILEVEL IllDATA BASESITE-Figure 1 A . I . S l o p e stabiliry analysisflowchart.We hope you find the guide to be useful. If you find portions of it unclear,debatable, or in error, we would like to hear from you. Names and addresses of theauthors for each section are listed at the beginning of the section.1A.3Suggested Use1A.3.1 LandManagersThe first two sections of the guide will serve land managers' needs by introducingthem to the three-level system and its use in resource planning. The remainder ofsection 1 describes the three-level system, its general methods of analysis, and itslimitations. In section 2 we discuss the use of slope stability assessment in resourceplanning. After reviewing these two sections, the manager should be able tocommunicate better with-and understand the degree of confidence communicatedby-the investigator.The details of investigative and analysis techniques (sections 3-5) may not be ofinterest to the land manager, but the methods of stabilization in section 6 may help inunderstanding alternative solutions.

1A.3.2 Geologists/EngineeringGeologistsGeologists and engineering geologists will have use for the entire design guide, butwill probably find the techniques for level I and I1 analyses the most useful. Thesetwo levels, for reconnaissance and project planning, respectively, describe a methodof predicting slope instability over large areas.Reconnaissance-level assessment refers to the analysis of large areas for relativelandslide-hazard potential. This level of analysis is used for input to forest planning,timber sale and resource allocations, environmental assessment reports, andtransportation planning. The LISA (Level I Stability Analysis Ver. 2.0 1991)computer model discussed in the guide can be used to delineate areas susceptible tolandslides on a broad scale to alert land managers to those areas where the risk isgreatest (Hammond et al., 1992).Project planning refers to the analysis of designs proposed to implement amanagement objective. For example, a proposed road corridor is analyzed forpreconstruction and postconstruction slope stability. This also includes a sensitivityanalysis for individual proposed road design segments that cross potentially unstableareas identified in LISA. DLISA (Deterministic Level I Stability Analysis Ver. 1.021991) works well for sensitivity analysis. An evaluation of road prism conditions(e.g., cut slope heights and angles, fill slope angles and depths, fill compaction, anddrainage) can be completed with the results from the sensitivity analysis. A level I1computer program, SARA (Stability Analysis for Road Access), is being developedand DSARA (Deterministic Stability Analysis for Road Access) is being perfected atthe Intermountain Research Station.Experienced geologists and engineering geologists will find level I and I1 analysesuseful when a proposed project may change soil physical properties, slopeconfiguration, or surface and subsurface water flow. Experienced engineeringgeologists understand the basic concepts contained in the guide. Those geologistswith little experience in the engineering arena may not be familiar with the analyticaltechniques used. Those freshly out of school with degrees in classical geologyshould seek additional training to gain a working knowledge in soil mechanics,strength of materials, and basic road design. For the less experienced practitioner, amentor assisting and verifying input data will help ensure accurate results.1A.3.3GeotechnicalEngineersGeotechnical engineers will have use for the entire guide, but will probably find thesections explaining design applications for level I1 (project planning analysis) andlevel I11 (site-specific analysis) the most useful. During a project design, efforts aregenerally made to minimize cost, which usually translates into the minimumfunctional design. However, site constraints or aesthetic considerations may require adeviation from the standard textbook procedure. This guide shows how to calculatefactors of safety for these minimal or unique solutions. It is also useful in answeringdesign questions where standard designs are inappropriate.During failure analysis, the guide is useful in leading one through the backcalculation process. By back-calculation, the failure parameters can be deduced.Designing a repair is then a matter of bringing the factor of safety up to a desiredlevel by buttressing, drainage, or other means. Usually, several alternatives forfailure correction are possible. The guide shows ways to analyze these alternativerepairs and calculate their factors of safety. Coupled with cost data, thesealternatives can be presented to management.

Geotechnical engineers understand the concepts and analysis techniques contained inthe guide. Most civil engineers are familiar with these methods. Those who havenot worked a number of these problems in the past may want a peer review of theirmethods and nnel without formal geotechnical training-such as many hydrologists, soilscientists, foresters, and other specialists-may use the guide to gain anunderstanding of the types of slope stability problems that geotechnical personnel areable to analyze and solve. Non-geotechnical specialists having extensive exposure toand experience with the underlying concepts and analytical techniques of the guidewill find it useful in the understanding of slope stability problems.The reader must bear in mind that an understanding of the slope-movement processesbeing modeled, as well as how the model represents the processes, is nee

slope, rock, soil, and drainage characteristics and geologic processes. These analyses are often completed using slope stability charts and the DSARA (Deterministic Stability Analysis for Road Access) slope stability program. The probabalistic SARA (Stability Analysis for Road Access) program is still under development.

Related Documents:

Lesson 4-1 Chapter 4 5 Glencoe Algebra 1 Study Guide and Intervention Graphing Equations in Slope-Intercept Form Slope-Intercept Form Slope-Intercept Form y mx b, where m is the given slope and b is the y-intercept Write an equation in slope-intercept form for the line with a slope of -4 and a y-intercept of 3. y The mx b Slope .

FHWA NHI-06-088 6 – Slope Stability Soils and Foundations – Volume I 6 - 3 December 2006 6.1 EFFECTS OF WATER ON SLOPE STABILITY Very soft, saturated foundation soils or ground water generally play a prominent role in geotechnical failures in general. They are certainly major factors in cut slope stability and inFile Size: 1MBPage Count: 62

Characterization of slope failures is complicated, because the factors affecting slope stability can be difficult to discern and measure, particularly soil shear strength parameters. Extensive research has been conducted on slope stability investigations and

Reliability analysis of slope stability has attracted considerable research attention in the past few decades [6]-[10]. Reliability of slope stability is frequently measured by „„reliability index,‟‟ and slope failure probability, P f, which is defined as the probability that the minimum

A positive slope creates a line that goes up/right. A negative slope creates a line that goes down/right. Slope – steepness and direction of a line Section 4-1: Slope (Day 1) y x y x 1 2 . 133 SWBAT calculate the slope of a line base on a graph Example 1: Find the slope of the line. m 2/6 .

Write an equation of a line in slope-intercept form with the given slope and y-intercept.Then graph the equation. slope: 2, y-intercept: 4 62/87,21 The slope-intercept form of a line is y mx b, where m is the slope, and b is the y-intercept. Pl

Oct 24, 2011 · More Math Worksheets and Printables available at www.MathWorksheetsGo.com . The Slope Formula . . If a line has a positive slope, what is its general direction? C) Describe the direction of a line with a slope of zero. . Sketch a line with a negative slope . Part II. What is the slope

Modern Approaches to Management *Separated Bureaucracy from Classical School. Lawal (2012) 1. Classical School of Management 2. Organic or Neo-Classical School (Human Relations and Behavioural Theories) 3. System and Contingency School 4. Dynamic Engagement Era * Agreed with Stoner et al. (2004) by Identifying New School (No. 4) Robbins and Coulter (2009) 1. Classical Approach 2. Quantitative .