Sliding Stability

Learn from the failure of Bayless Dam due to instability at DamFailures.org

"Stability must be assessed on selected surfaces within the structure... Sliding safety must also be assessed at/or near the foundation-structure interface. This surface may be either level or sloping. Generally, it may by assumed that a surface that slopes upward (in the direction of possible sliding) will have a beneficial effect, while one that slopes downward will increase the possibility for sliding... Where a shallow weak seam exists below a structure's contact with the foundation, or a structure is imbedded below the top of the foundation, two possible failure modes are present. One mode involves slippage along the weak plane directly under the structure plus slippage along a plane through the foundation above the weak seam (crossbed shear for rock or passive resistance for soil). When the weak seam extends a large distance past the toe of the structure without daylighting, the second mode will usually be critical."^[1]