Abstract: To promote the application of a fullface hard rock machine (TBM) in pumped storage power stations, a compact TBM with an ultrasmall turning radius is designed. First, based on the geological conditions and characteristics of the drainage gallery tunnel project of the pumped storage power station, the design characteristics of the compact TBM are analyzed. The major problems that must be addressed when a compact TBM is applied to the drainage gallery tunnel project of the pumped storage power station, such as cutterhead rock breaking capacity, smallradius curved tunneling, and station crossing construction technology, are proposed to improve the adaptability and tunneling efficiency of the compact TBM. Second, the targeted design and optimization improvement measures for the smallradius curved turning tunneling, rapid station crossing, and efficient rock breaking of the compact TBM are investigated, including a new thrust system, an automatic guidance system for an ultrasmall turning radius, integrated belt conveyor, and central and disc cutter structures. Finally, a selfdeveloped compact TBM with independent intellectual property rights is applied to the drainage gallery tunnel project of the Wendeng pumped storage power station. Results show good geological adaptability and positive mechanized construction advantages of the compact TBM.

Key words: tunnel, pumped storage power station, drainage gallery, compact TBM, smallradius curved tunneling, type selection and design