A chart-based seismic stability analysis method for rock slopes using Hoek-Brown failure criterion

Abstract

The parameters of rock mass structures, strength and seismic effect are critical factors for the seismic stability analysis of rock slopes. This paper demonstrates the use of a new form of a chart-based slope stability method that satisfies the Hoek-Brown (HB) criterion. The limit equivalent method is used to assess the stability of rock slopes subjected to seismic inertial force. First, stability charts for calculating the factors of safety (FoS) with a slope angle of β=30° in static and pseudo-static states were proposed by using Slide 6.0 software. Next, scaling factors of the horizontal seismic acceleration coefficient (fKh) and slope angle (fβ) were established to illustrate the influence of the horizontal seismic load and slope angle on the stability of rock slopes, respectively. Using regression analyses of fKh and fβ, a fast calculation model was proposed to solve the slope safety factors based on the stability charts. Finally, the stability charts analysis method (SCAM) was verified against the numerical solutions; the results showed that 70.63% of the data had discrepancies of less than ±10%, and the data with discrepancies greater than ±10% were associated with high values of geological strength index (GSI) and horizontal seismic acceleration coefficient (Kh). The proposed model calculating the FoS of rock slopes is simple and straightforward to use for seismic rock slope design and stability evaluation.