Foaming composition
AssigneeMBT Holding AG
InventorPeter Ellenberger
Life of this patent
Estimating the term…
Abstract
A method of boring a tunnel through a stratum utilizing a shield tunneling apparatus, the process comprising the injection into the stratum at the cutting face of an aqueous material comprising (a) from 0.005-0.05% by weight of a polyethylene oxide of weight-average molecular weight from 2,000,000 to 8,000,000 (b) from 0.05-0.5% by weight of a sulphate-containing anionic surfactant. The method is effective even in difficult soils.
Claims14
A method of boring a tunnel through a stratum by means of a shield tunneling apparatus, the process comprising the steps of:
- boring a tunnel, and
- the injection into the stratum at the cutting face of an aqueous material comprising
- (a) from 0.005-0.05% by weight of a polyethylene oxide of weight-average molecular weight from 2,000,000 to 8,000,000
- (b) from 0.05-0.5% by weight of a polyoxyalkylene alkyl ether sulphate, where the polyalkyleneoxide chain has an average chain length of 2-3 alkylene oxide units.
A foaming material adapted to assist the conveyance of soil from the cutting face of a shield tunneling apparatus, comprising
- (a) from 0.005-0.05% by weight of a polyethylene oxide of weight-average molecular weight from 2,000,000 to 8,000,000
- (b) from 0.05-0.5% by weight of a polyoxyalkylene alkyl ether sulphate, where the polyalkyleneoxide chain has an average chain length of 2-3 alkylene oxide units.
A method of boring a tunnel through a stratum by means of a shield tunnelling apparatus the process comprising the steps of:
- boring a tunnel and,
- injection into the stratum of an aqueous material comprising:
- (a) from 0.005-0.05% by weight of a polyethylene oxide of weight-average molecular weight from 2,000,000 to 8,000,000 and having an average chain length of 2-3 alkylene oxide units;
- and,
- (b) from 0.05-0.5% by weight of a polyoxyalkylene alkyl ether sulphate surfactant.
Dependencies are inferred from the claim text.