Scoops3D—Software to Analyze Three-Dimensional Slope Stability Throughout a Digital Landscape Chapter 1 of Section A, Modeling Methods Book 14, Landslide and Debris-Flow Assessment 1.0 1.4 F 1.8 2.2 Relative stability, Relative stability, 2.6 Techniques and Methods 14–A1 U.S. Department of the Interior U.S. Geological Survey Scoops3D—Software to Analyze Three-Dimensional Slope Stability Throughout a Digital Landscape By Mark E. Reid, Sarah B. Christian, Dianne L. Brien, and Scott T. Henderson Chapter 1 of Section A, Modeling Methods Book 14, Landslide and Debris-Flow Assessment Techniques and Methods 14–A1 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2015 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS (1–888–275–8747) For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Reid, M.E., Christian, S.B., Brien, D.L., and Henderson, S.T., 2015, Scoops3D—Software to analyze 3D slope stability throughout a digital landscape: U.S. Geological Survey Techniques and Methods, book 14, chap. A1, 218 p., http://dx.doi.org/10.3133/tm14A1. ISSN 2328-7055 (online) Contents Abstract ....................................................................................................................................................................... 1 Chapter 1. Introduction ........................................................................................................................................... 2 1.1. Purpose and Scope .......................................................................................................................................... 2 1.2. Capabilities and Limitations .............................................................................................................................. 5 Chapter 2. Basis of the Slope-Stability Analysis .................................................................................................... 7 2.1. Potential Failure Mass, Slip Direction, and Weight ........................................................................................... 9 2.2. Shear Strength ............................................................................................................................................... 14 2.3. General Moment Equilibrium .......................................................................................................................... 15 2.3.1. Ordinary (Fellenius) Method .................................................................................................................... 18 2.3.2. Bishop’s Simplified Method ...................................................................................................................... 20 2.4. Pore-Water Pressure Conditions .................................................................................................................... 22 2.5. Special Cases ................................................................................................................................................ 25 2.6. Slope Stability of 2D Slice .............................................................................................................................. 26 Chapter 3. Build and Search a 3D Domain............................................................................................................ 27 3.1. Construct a 3D Domain .................................................................................................................................. 27 3.1.1. Topography ............................................................................................................................................. 28 3.1.2. Material Properties in the Subsurface ...................................................................................................... 30 3.1.2.1. Homogeneous Properties ................................................................................................................. 30 3.1.2.2. Layered Material Properties .............................................................................................................. 32 3.1.2.3. 3D Properties .................................................................................................................................... 32 3.1.3. Groundwater Configuration ...................................................................................................................... 33 3.1.3.1. None ................................................................................................................................................. 33 3.1.3.2. Pore-Pressure Ratio, ru ..................................................................................................................... 33 3.1.3.3. Piezometric Surface .......................................................................................................................... 33 3.1.3.4. 3D Pressure Heads ........................................................................................................................... 34 3.1.3.5. 3D Variably Saturated Configurations ............................................................................................... 34 3.1.4. Earthquake Loading................................................................................................................................. 35 3.2. Search of the 3D Domain ............................................................................................................................... 35 3.2.1. Simple Box Search .................................................................................................................................. 38 3.2.2. Coarse-to-Fine Box Search ..................................................................................................................... 40 Chapter 4. Program Operation ............................................................................................................................... 43 4.1. System Requirements and Installation ........................................................................................................... 43 4.2. Running Scoops3D ........................................................................................................................................ 43 4.3. Using Scoops3D-i, the Graphical User Interface ............................................................................................ 46 4.3.1. Basic Tasks with Scoops3D-i .................................................................................................................. 46 4.3.2. Getting Started with Scoops3D-i .............................................................................................................. 46 4.3.3. Create a New Input File for Scoops3D .................................................................................................... 48 4.3.3.1. Description and Units ........................................................................................................................ 48 4.3.3.2. Topography ....................................................................................................................................... 49 4.3.3.3. Subsurface Conditions ...................................................................................................................... 49 4.3.3.4. Stability Analysis: Limit-Equilibrium Method ...................................................................................... 53 iii 4.3.3.5. Stability Analysis: Search Method ..................................................................................................... 53 4.3.3.5.1. Box Search ................................................................................................................................. 53 4.3.3.5.2. Single Trial Surface .................................................................................................................... 56 4.3.3.5.3. File Search ................................................................................................................................. 58 4.3.3.6. Additional Output Options ................................................................................................................. 60 4.3.3.7. Save a Scoops3D Input File .............................................................................................................. 61 4.3.4. View and/or Modify an Existing Scoops3D Input File ............................................................................... 61 4.3.5. Create a New Input File for Scoops3D Using a Single Trial Surface from a Previous Scoops3D Run .... 61 4.3.6. Check a Scoops3D Input File for Completeness ....................................................................................