GB755977A - Improvements in or relating to the plugging of tubular shafts in pile constructions - Google Patents

Abstract

755,977. Piles. BRITISH STEEL PILING CO., Ltd., and COX, B. C. A. Dec. 21, 1954 [Jan. 14, 1954], No. 1147/54. Class 68(2) A method of plugging the lower end of a tubular shaft in the sinking thereof consists in positioning a mass of chain or the like together with or without an aggregate such as sand or ballast with or without cement in the tubular shaft and withdrawing the chain during formation of the pile. The tubular shaft 1 with a shoe 2 closing the end is driven in the normal manner to the required depth as shown in Fig. 1 and a quantity of concrete 3 placed in the bottom sufficient to form an enlarged bulbous foot to the finished pile. A length of chain 4 is then fed into the shaft 1, through a guide 5, to lie on the top of the concrete 3 in an evenly distributed mass 6 and a further quantity of concrete 7 is then introduced on top of the mass 6. The lower part of shaft 1 has internal projections 8 to. assist jamming action of the chain mass 6, and the shaft is withdrawn till the mass 6 lies under the projections 8, the amount of concrete 3 and chain mass 6 being suitably arranged. The shaft 1 is then redriven through the concrete 3, as shown in Fig. 3, the mass 6 forming a rigid plug preventing rising of the concrete in the shaft 1. The chain 4 may then be withdrawn, the concrete 7 replacing the chain mass 6, and the pile completed in the normal manner. For use in bottom or base driving cased piles or tubes for cast-in-situ piles, the chains is fitted into the bottom of the casing tube and is tamped down by an internal drop hammer. Ledges may be provided, but facing upwards instead of downwards.