New criteria for defining slope failure using the strength reduction method

• An energy balance equation is derived when the SRM is employed.
• The relationship between the energy change and the slope failure is analyzed.
• Several new criteria are presented to define slope failure based on energy change.
• The reliability of the proposed criteria is verified.
• The proposed criteria have some advantages over the conventional criteria.

The success of the strength reduction method (SRM), which is one of the dominant methods for quantifying slope stability, is substantially dependent on the definition of slope failure. The criteria that have been developed to define slope failure are based on changes in the stress, strain and displacement distributions in the slope. However, these distributions are usually complicated. To skip the complex distributions, this paper develops several new slope failure criteria that are based on energy change, which is closely related to the slope failure driven by energy. First, an energy balance equation that can express the energy change is derived from the conservation of energy principle when the SRM is used to analyze slope stability. The relationship between the energy change and slope failure is then analyzed, and charts with regard to the new slope failure criteria based on the substantial changes in energy are developed. The reliability of the proposed criteria is verified using 2D and 3D slope cases. Defined by the energy change, which is a scalar quantity, the new criteria possess accurateness and physical meaning, and are recommended for the 3D slope.