Abstract: The development status of tunnel grouting technology recently is summarized as follows. (1) Tunnel grouting technology develops rapidly with engineering construction, and its relevance continuously increases. The application scenarios have extended from water blocking and ground improvement to engineering emergency rescue, disease control, gas prevention and control, thermal insulation, etc. (2) Significant breakthroughs have been made in grouting theory, materials, equipment, and effect inspection methods, thereby promoting the development of tunnel grouting technology and realizing highly efficient and controllable grouting. (3) The tunnel grouting technology has overcome the construction limitations of various extremely complex strata, such as underwater weathered groove, (high pressure) waterrich fault fracture zone/dense joint zone, and waterrich fine sand layer. The Chinese tunnel grouting technology has reached an international advanced level. With the construction and planning of the SichuanTibet railway and the straitcrossing tunnels, tunnel construction has further penetrated the once restricted areas of engineering geology and problems such as extremely highwater pressure, highpermeable strata, highground stress, highground temperature, and highactive faults are becoming prominent. Thus, further deepening of grouting theory study, innovation and optimization of grouting technology, research and development of new grouting materials, customized matching drilling equipment, and quantitative determination of grouting effect are required to promote the continuous development of tunnel grouting technology.

Key words: tunnel with complex geologies, development of grouting technology, deep weathered groove, high ground temperature, high water pressure