Abstract: Upward floating and dislocation often occur to shield segments during construction. Therefore, a physical property test is conducted on doublecomponent grout with different mixing proportions of strengthpromoting dry powder (material A) and liquid activator (material B). On this basis, a novel synchronous doublecomponent grout with adjustable initial setting time is developed. The results indicate the following: (1) The initial setting time of synchronous doublecomponent grout can be controlled within 30~60 min by a reasonable mixing ratio of materials A and B. (2) The initial setting time and fluidity of the novel doublecomponent grout are principally controlled by material B. With the increase of the mixing proportion of material B, the initial setting time and fluidity decrease significantly and tend to be stable when the mixing proportion of material B is more than 3%. (3) The strength of the novel doublecomponent grout stone body is controlled by materials A and B. When the mixing proportions of materials A and B are 1.5% and 3.5%, respectively, the strength of the stone body basically reaches the maximum value. (4) The optimum mixing proportions of materials A and B are 1.5%~3.71% and 1%~2.2%, respectively. The novel synchronous doublecomponent grout has been applied in the underground utility tunnel project in the central urban area of Guangzhou, China, and the assembly quality of segments has been greatly improved. This indicates that the novel doublecomponent grout has good filling and pumping performance, and it addresses the construction problem of synchronous grouting of singlecomponent and traditional doublecomponent grout in the fullsection surrounding rock stratum.

Key words: shield tunnel, synchronous double , component grout, initial setting time, fluidity, stone body strength, property test