Abstract: Backfill grouting is a critical step in the process of shield tunneling construction. In order to explore the development of slurry strength, we obtained sands of three different fineness modulus(1.652,1.096,0.773) by using different sieving methods and prepared inert slurry and rigid slurry by using the sands. Through setting time test, direct shear test and cubic compressive test, we observed the effect of fineness modulus of sand on the setting time and strength of inert slurry and rigid slurry. Results show that strengths of the two slurries decrease with the increasing of fineness modulus of sand. Moreover, cement hydration in rigid slurry mainly promotes the increase of cohesion and the decrease of internal friction; while the action of fly ash in inert slurry can be ignored.

Key words: slurry shield, backfill grouting, fineness modulus of sand, inert slurry, rigid slurry, compressive strength, triaxial test