Investigation and Prevention of Cut Toe Layout of Hydraulic Structures on Steep, Hard and Soft Slopes

Large water conservancy and hydropower projects in China are mostly located in the high mountains and canyons of southwest provinces. The layout of various hydraulic structures needs to be excavated to form large-scale high and steep engineering slopes. For the stability of high slopes, China has formed rich research results and basically mature engineering cognition, but most of the research results focus on one or two unfavorable engineering geological problems. At the same time, there are relatively few studies on the stability analysis of a number of complex adverse geological problems and excavation conditions. This paper takes the excavation slope of the power station building on the right bank of the Hanshan Gushan Navigation Power Junction under construction as an example, aiming at the high and steep slope formed after the excavation of the foundation pit of the power station building, and at the same time, the slope has many complex geological conditions and excavation schemes that adversely affect the stability of the slope (Song et al. in J Eng Geol 20:123–130, 2012), such as “hard rock above and soft rock below”, “interlayer shear zone”, “bedding rock slope”, “slope excavation and toe cutting”. In combination with a large number of early investigation and numerical simulation scientific research achievements of the slope, the main engineering geological characteristics and key technical problems of the slope are summarized, the deformation and failure mode, failure characteristics and deformation and failure mechanism of the slope are deeply studied, and the slope is divided into three governance areas according to different geological conditions of the slope. Different control measures are taken in different governance areas, which not only ensure the prevention effect of the slope (Xiao et al. in China Energy Environ Prot 42(3):54–60, 2020), but also save investment. The successful treatment cases of the high and steep slope of the hydraulic structure under a number of complex adverse geological conditions and excavation conditions have a good reference significance for the stability analysis and prevention measures research of the high and steep slope of similar projects in the western region.