Research status and development trend of deep geological exploration techniques for hydraulic and hydropower engineering

With the advancement of national infrastructure construction and energy resource development strategies, hydraulic and hydropower development in Western China has exhibited a deeper and larger-scale trend. However, due to the complexities of deep geological environments and limitations in exploration techniques, deep engineering often faces challenges posed by high-energy geological conditions, such as elevated in-situ stress, high ground temperatures, and significant hydraulic pressures. Consequently, these factors present a series of challenges for the planning and implementation of major national projects, underscoring the necessity for the development of exploration and testing techniques tailored to deep conditions. This paper summarizes the current state of research on deep geological exploration and testing techniques, including ultra-deep directional drilling methods, deep geophysical exploration techniques, detection methods during tunneling or drilling, in-situ testing techniques, and the classification and parameter values of deep rock masses. It also identifies existing challenges within these areas. Furthermore, the paper discusses the development trends in deep geological exploration and testing techniques. The research findings will provide a foundation for deep engineering construction and the exploitation and utilization of deep resources.