Abstract:

The effects of carboxymethycellulose (CMC),polyvinyl alcohol(PVA)and sodium polyacrylate(PNaAA)on the properties of the grouting material used in shield tunneling,such as the quantity of water seeping,the fluidity,the setting time and the rheology of cement paste,were investigated. In this investigation,a high-effi-ciency water reducer GCL1-3A was mixed into the grouting material.The results reveal that(1)CMC and PNaAA possess excellent water-property for the grouting material,while PVA does not display this property till six hours later;(2)with the usage of 3% (mass fraction)in the water reducer,CMC and PNaAA can enhance the flu-idity and stability of the grouting material;(3)CMC and PNaAA can accelerate the concreting of the grouting ma-terial while PVA is of the opposite efect;and(4)the original setting time of the grouting material with CMC or PNaAA being added is about 1 3 h,which is 1 h shorter than that of the grouting material without any polymer being added.

Key words: words, polymer, grouting material, property, shield tunneling