Assessment of the risk of rockfalls in Wu Gorge, Three Gorges, China

Abstract

In 2007 and 2008, six big damaging rockfalls occurred at four sites in Wu Gorge, the second gorge of the Three Gorges, China. Detailed surveys and aerial-photographic interpretation identified 104 potentially dangerous rock masses. This paper reviews previous rock-mass risk ratings, examines dangerous rockmass structure and presents a new assessment system for rockfall risk (ASRFR) in the Wu Gorge area. The ASRFR considers 15 factors: seven factors for hazard and eight factors for consequence. Relative importance weights for these factors are ascertained using an analytic hierarchy process. Using an equation to calculate the risk, the 104 dangerous rock masses were divided into three risk groups: high risk (33 sites), medium risk (33 sites) and low risk (38 sites). The ASRFR analysis can be used to divide the shipping route through the Wu Gorge into seven courses each of one of three classes: safe-route regions, yellow-alarm regions and red-alarm regions. The system provides geological information and a rockfall-risk management tool for local government and the shipment-route department.

Analysis of waves generated by Gongjiafang landslide in Wu Gorge, three Gorges reservoir, on November 23, 2008

“…Kinematic characteristics of the landslide and wave According to previous study results, the landslide resulted from structural collapse and instability due to the loss of support (Bolin et al 2010), which resulted in rapid failure. The Gongjiafang landslide incidents were captured using a camera.…”

Quantification and Management of Rockfall Risk in Opencast Quarrying Activities

“…Risk assessment is a well-defined procedure that has been applied to the management of workers' safety (see, e.g., European Commission, 1996;Faina et al, 1996;and Ballestrazzi et al, 1996) and to geological risks using different approaches, but these approaches are all based on the same basic concepts (see, e.g., Cancelli and Crosta, 1993;Bunce et al, 1997;Guzzetti et al, 2003;Lateltin et al, 2005;Campus et al, 2007;Mö lk and Poisel, 2008;Wieczorek et al, 2008;and Bolin et al, 2009). The definition that is most commonly used by the previously mentioned authors is discussed hereafter, Figure 1.…”