Abstract:

Sequential supporting technology is proposed based on the quantitative design and the quality control standard of the whole construction process, in order to further improve the intelligent construction level of the tunnel and accelerate the construction advance rates. With the intelligent construction of the trial sections of tunnels on YichangXingshan highspeed railway as the research object, the design of the sequential supporting for different surrounding rocks, the safety during the construction and the advance rate improvement effect are comprehensively studied, and the following conclusions are drawn: (1) When the growing rate of the strength of the supporting structure is not lower than that of the pressure of the surrounding rock, it is feasible to construct sequential primary supporting and the construction safety can be ensured. (2) Sequence I primary supporting shall give full play to the selfbearing function of the surrounding rock and meet the requirements of the matching between the surrounding rock pressure growing and the support strength. The lag distance of Sequence Ⅱ reinforcing primary supporting shall be as short as possible while meeting the requirements of the space required by the construction equipment needed for multiprocess operation cycles, so as to give full play to the early loadbearing function of the primary support. (3) Sequential supporting is based on quantitative design and precise construction, so it is necessary to strictly control the tunnel construction quality and the supporting opportunity. (4) Sequential supporting is applied in the trial sections of tunnels on YichangXingshan highspeed railway, and the construction advance rates of Ⅲa Type A, Ⅲa Type B, and Ⅳa Type C sequential supporting are increased by 46.5 %, 14.7 %, and 9.36 % respectively.

Key words: highspeed railway tunnel, drillingandblasting method, intelligent construction, sequential supporting, safety factor, support design theory; construction efficiency