Zonation of the landslide hazards in the forereservoir region of the Three Gorges Project on the Yangtze River
Introduction
The Three Gorges Project (TGP) on the Yangtze River is now underway. Many geological studies relating to the project have been carried out for more than half a century, with a good deal of informative results (Du, 1990, Gao, 1992, Yuan et al., 1996, Wu et al., 1996, Tan et al., 1997). The most important problems concerning the geological environment of the area in question that are closely related to the resettlement of local residents and reconstruction of counties and towns involved are: (1) the stability of reservoir bank slope; (2) prediction of landslide occurrence; and (3) zonation of landslide hazards in the region. The present paper will focus on the zonation of landslide hazards using an integrated information model based on the statistics of landslides that have occurred in the forereservoir region (within 100 km of the Three Gorges dam site) over the last five years (Fig. 1).
Section snippets
Geological setting
The forereservoir region here referred to covers an area that will be inundated when the planned reservoir is filled with water at a level of 175 m i.e. within the range of 30°40′–31°10′N and 110°–111°E. It is double layered consisting of pre-Sinian crystalline basement and the supracrustal Sinian–Jurassic sedimentary cover. The former, outcropped only in the core of Huangling anticline (the Three Gorges dam is situated in the core) and Shennongjia anticline, is composed of pre-Sinian
Distribution of landslides and factors affecting the slope stability
There are altogether 16 large old landslides and landslide-prone masses along the river valley around the forereservoir area of the TGP. An overwhelming majority of them are concentrated in two sections. In the Xiangxi–Xingtan section, 10 km long, 4 landslides have occurred. In the Badong section, 30 km long, 10 landslides are distributed.
It is known from the statistical data and case studies of typical landslides that there are five major factors that contribute to the occurrences of landslides:
Zonation of landslide hazards area
Information models so far used for landslide danger assessment fall broadly into two categories — the integrated information model and the logic information model (Yan, 1988, Yan et al., 1989, Yin et al., 1991, Wu, 1995, Wu et al., 1997). An integrated information model is adopted in this paper.
What is most considered in the model is the amount of available information related to landslides in the study region. For any given slope, it is expressed as:where P(B/Ai
Conclusions
A zonation of landslide hazards areas for the forereservoir region of the TGP on the Yangtze River by the information model expressed by Eq. (2) is made based on the landslide investigations and engineering geological survey over the last five years. Of the five landslide-prone areas, the first two cover an area of less than 5% of the total region, and are at a distance of more than 20 km from the Three Gorges dam site, and so a landslide there will impose no direct impact to the TGP, but may
Acknowledgements
This work was supported by a grant (95-913-06-02-04) from the National ninth five year plan science project and of Laboratory of Geomechanics. The authors are most grateful to Prof. Chen Qingxuan, member of the Chinese Academy of sciences for his suggestions in the revision of the manuscript.
References (11)
Landslide and Debris Flow of the Reservoir Region of the Three Gorges Project on the Yangtze River
(1990)Crust Stress Field and Earthquake of the Three Gorges Area of the Yangtze River
(1992)- et al.
Assessment and zonation of regional crustal stability in and around the dam region of the Three Gorges project on the Yangtze River
Environ. Geol.
(1997) Engineering Geology of the Regional Crustal Stability in the Qingjiang River Basin of Western Hubei Province
(1995)- et al.
Structural Heterogeneity and Compatibility in the Three Gorges Area of the Yangtze River
Cited by (104)
Determination of shear failure regions of rock joints based on point clouds and image segmentation
2019, Engineering GeologyA comparative study of an expert knowledge-based model and two data-driven models for landslide susceptibility mapping
2018, CatenaCitation Excerpt :Two areas located in the middle-upper reach of the Yangtze River in China, the Kaixian and Three Gorges study areas (Fig. 1), were used to perform the expert knowledge-based model, the logistic regression model, and the artificial neural network model. The areas are recognized as having a high, natural risk for landslides (Wu et al., 2001; Liu et al., 2004; Zhu et al., 2004, 2014). The Kaixian study area, with a total area of about 250 km2, is located in Kaixian County (Fig. 1), Chongqing Municipality.
Towards a complete understanding of the triggering mechanism of a large reactivated landslide in the Three Gorges Reservoir
2018, Engineering GeologyCitation Excerpt :The Quchi landslide is located at a distance of around 11 km from Wushan County and situated at the mouth of Qutang Gorge, which is the first gorge of the well-known Three Gorges in the middle reaches of the Yangtze River (namely, Qutang Gorge, Wu Gorge and Xiling Gorge, as shown in Fig. 1a). The geology of the area consists of two major components: a pre-Sinian crystalline basement, and a supra-crustal Sinian-Jurassic sedimentary cover (Wu et al., 2001). The former, which is composed mainly of magmatic and metamorphic rocks, outcrops only sporadically in this area.
Displacement prediction of Baijiabao landslide based on empirical mode decomposition and long short-term memory neural network in Three Gorges area, China
2018, Computers and GeosciencesCitation Excerpt :The Three Gorges area is one of the most landslide-prone areas in China. This area is long and narrow and extends along the midstream of the Yangtze River, which flows between massive limestone mountains with steep slopes (Wu et al., 2001). The Xintan landslide, the most famous landslide in the Three Gorges area, resulted in the sinking of 64 wooden boats and 13 small motorboats and the deaths of 10 boatmen.