Abstract: Aiming at the problem of excessive uplift of segment in full-section stable surrounding rock strata, a new type of synchronous two-component grout is developed and applied to a section of Nanjing metro line 6 through the combination of laboratory test and field test, which greatly reduces the uplift of segment and improves the quality of segment assembly. The single-liquid hard grout used in the field is used as liquid A, and the new coagulant is used as liquid B. The influence of liquid B on the properties of liquid A is determined by laboratory test. According to the requirements of slurry gel time, fluidity, compressive strength, and combined with the actual situation on site, the ratio of new synchronous two-component-liquid grout is determined. The grouting effect of the new synchronous two-component-liquid grout is verified by field test. The results show: (1) The gel time of the new synchronous two-component grout can be shortened to 10-30 minutes by mixing 1 %-2 % of the total mass of liquid A with liquid B. The slurry has good pumping performance and high early strength. (2) The fluidity of the new synchronous two-component grout can not be lost within 10 min after injection, and with good pumping perforrnance and not easy to block the pipe. (3) Monitoring data show that the new synchronous two-component grout has excellent field grouting effect. Compared with the single hard grout, the overall uplift of the segment ring is reduced by 50%, the maximum horizontal deviation of the segment ring is reduced by 57%, the number of leakage points of the segment ring is reduced by 50%, and the maximum surface settlement is reduced by 74.3%.

Key words: tunnel engineering, segment uplifting, field test, synchronous two-component grout, gel time