# Development Pattern of Toppling Deformation Slopes in Western China
###### Abstract  
Controlled by regional geological background, and affected by human activity and weathering, toppling deformation slopes occur in different regions in China. Based on statistics about domestic toppling deformation slopes and their distribution, the regional geological susceptibility zonation area of toppling deformation slopes was determined. Firstly, a regional geological susceptibility evaluation was conducted according to these toppling deformation slopes, choosing landform, stratigraphic age, seismic intensity and tectonic stress distribution, and the study area was divided into very low, low, medium, high and very high susceptibility areas. Secondly, a geographic position susceptibility evaluation was conducted aimed at different sections of typical rivers in western China and the toppling deformation slopes related to them, and the study area was divided into upstream, midstream and downstream of 11 rivers that were respectively classified into very low, low, high and very high susceptibility areas. Thirdly, based on the results, associations between the toppling deformation factors (lithology, slope height, elevation, horizontal depth and vertical depth) and the distribution of deformation slopes were revealed. Finally, the development regularity was analyzed comprehensively. The results show that the toppling deformation slopes of hydropower projects are more developed in Sichuan, Qinghai and Yunnan provinces of China. With regard to regional geography, besides the Yellow River, both the Lancang River and the Yalong River flow through areas with toppling deformation that are classified as highly susceptible geological zones in all levels. The results of this study can be used as references for site selection plans in hydropower projects.  
toppling deformations; regional geology; western hydropower projects; geographical position; susceptibility; development regularity  
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Until now, most studies on toppling deformations, especially in hydropower projects, have focused on the evolutionary process [13; 14; 15; 16], deformation mechanisms [17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28] and development characteristics [29; 30; 31; 32] of single toppling deformation slopes. The development regularity and susceptibility of toppling deformations are rarely studied from the angle of regional geological conditions and geographic position. Less has been achieved aiming at connections between the development factors (lithology, slope height, slope angle, elevation, horizontal and vertical depth) and the regional development regularity.  
In this work, based on the above, the susceptibility of the toppling deformations in western China is analyzed from the aspect of regional geology and geographic position in China, helping us understand the regional development regularity and providing references for hydropower station site selection.