Figure 4Rock-soil aggregate slope distribution in the dam site region of the Gushui Hydropower Station.As shown in Figure 4, there are CC-5013 numerous rock-soil aggregate slopes at different elevations. The slope scale ranges from small to extremely large, and the volume of each rock-soil aggregate slope and its impact on the hydropower station are different. In the dam site region of the Gushui Hydropower Station, the safety of the station at the construction and operation stages is influenced by 4 very large rock-soil aggregate slopes: the Gendakan slope, the Bahou slope, the Baqian slope, and the Zhenggang slope. In this paper, the Gendakan slope is selected as an example for study. Figure 5 shows the Gendakan slope at the Gushui Hydropower Station, located at the middle of reservoir, is approximately 4km away from the dam site and is distributed at an elevation of 2,060m�C2,800m.

The terrain slope is approximately 20��C30��, and there are three tablelands at elevation of 2,550m, 2,400m, and 2,250m. The Gendakan slope is mainly composed of outwash deposits with a layered structure, and the main particles are rock block, broken stone, and silt. The thickness of the outwash accumulation is approximately 70m�C80m, the maximum thickness is approximately 230m, and the volume is greater than 3,000��104m3.Figure 5The Gendakan slope at the Gushui Hydropower Station: (a) photograph of the Gendakan slope; (b) three-dimensional visualization.3.2. Layered Characteristics of Outwash AccumulationIn the Gushui Hydropower Station region, the outwash accumulation is well developed below 4,000m, especially below the 3,000m.

The main reason for the formation of the rock-soil aggregate is the melting of the glaciers, which generates surface water. An enormous amount of rock and soil particles are carried by the outwash, and they flow downward and are deposited. The rock-soil aggregate is mostly composed of rock block, broken stone, and clay or sandy soil. Because the geological history of the rock-soil aggregate formation is long, the slope evolution can be divided into many stages, and the layered characteristic of outwash accumulation is obvious. Figure 6 shows the layered rock-soil aggregate in the PD 33 (PD is a horizontal Carfilzomib exploration tunnel).Figure 6Layered rock-soil aggregate in the PD 33: (a) and (c) are the small size particle rock-soil aggregates; (b) and (d) are the large size particle rock-soil aggregates.As shown in Figure 6, the particle size of each rock-soil aggregate layer is different, and there exist nonuniform distribution characteristics.