Design Process

Determining Foundation Strength Parameters

Methods of Analysis

Analytical Techniques for Multi-wedge Systems

Design Considerations - ETL-1110-2-2560007

Figure 1. Sign Convention for Geometry

Figure 2. Geometry of the Typical ith Wedge and Adjacent Wedges

Figure 3. Distribution of Pressures and Resultant Forces Acting on a Typical Wedge

Figure 4. Free Body Diagram of the ith Wedge

Figure 5. Derivation of the General Equation

Figure 6. Derivation of the General Equation

Figure 7. Derivation of the General Equation (cont)

Figure 8. Force Polygon for a Typical Wedge

Figure 9. Force Polygons for Upward and Downward Sliding

Notes for Figure 8 and 9

The effects of seepage froces should be included in the sliding analysis

Seismic Sliding Stability

Figure 10. Uplift Pressures

Required Factors of Safety

Figure 11. Seismically Loaded Gravity Dam

List of Symbols

List of Symbols (cont)

General - ETL-1110-2-2560025

Background - ETL-1110-2-2560026

Problems with Previous Design Criteria

Shear-Friction

List of Symbols for Inclosure 1

Examples

Example 1: Single Wedge

Example 2: Multiple Wedges

Free Body Diagram of Wedges

Sign Convention for General Equation

Example : Five Wedge System

Example : Five Wedge System (cont)

Example : Five Wedge System (cont)

Summary: Wedge Forces for Trial Safety Factors

Graphical Solution for Safety Factor

Alternate Method of Analysis

Case 1: Single-Plane Failure Surface

Use of Equations and Limitations of Analytical Techniques

Case Two: Multiple-Plane Failure Surface

Figure 3-1. Single Plane Failure Mode

Figure 3-2. Multiple Plane Failure Mode in the Simplist Form of Two Planes

Figure 3-3. Plot of nα and α for Values of tanφ/FS

ETL 1110-2-256

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