Method and apparatus for grouting of tunnel liners
OwnerPatrick J. Stephensinventor
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Abstract
A method and apparatus for filling cavities in underground excavations. Sodium silicate and aqueous foam are mixed with cement slurry to produce a quick-setting foamed cement grout having a meringue-like consistency. The high viscosity of the grout combines with the very fast initial set time to minimize the problem of grout flowing out of the cavity following injection. The method and apparatus are particularly suited to grouting of the annular cavity which is formed between the tail shield of a tunnel boring machine and a segmental tunnel liner which is assembled therein.
Claims8
A method for filling a cavity in an excavation, said method comprising the steps of:
- providing a cement slurry solution;
- mixing a sodium silicate solution with said cement slurry solution in an amount sufficient to accelerate hardening of a resulting cementitious mixture to a predetermined initial set time;
- mixing aqueous foam with said cementitious mixture so as to entrain air therein and thereby form a viscous, low shear-strength foamed cement grout, said aqueous foam being added to said cementitious mixture in an amount sufficient to provide said foamed cement grout with a viscosity which is sufficiently high to minimize flow of said grout through and out of said void prior to said initial set time;
- and
- flowing said grout into said cavity so that said cavity is filled thereby.
Dependencies are inferred from the claim text.