GB882085A - Improvements in or relating to the production of concrete foundation piles - Google Patents

Abstract

882,085. Cast-in-situ piles. GRIMAUD, G. March 14, 1958 [March 14, 1957; April 10, 1957; June 4, 1957], No. 8181/58. Class 68(2). An excavating device for use in forming cast-in-situ concrete piles comprises a threaded preparatory tube and at least a soil removing conveyer and a concentric concrete-filling tube and/or a boring crown and is characterised in that the attachments are adapted to be interchangeably secured within the preparatory tube without removing said tube from a working point already reached in the ground. An outer tube T (Fig. 1) which has a thread 4 is screwed into the ground and has pins 17 projecting internally which engage with slots 16 in a soil removing tube C, which has teeth 14 and is weighted by blocks 6a and 6b which also define a central bore 12 through which water can pass. The tube is divided longitudinally to expedite removal of the contents. In use the tube is carried down by the cuter tube T until full of soil and is hauled out by a cable 18 for emptying. In a modification, Fig. 5, the slots 16 are extended in length and without the curved portion. In a further modification of the tube C, for use in free running soils it is provided with an internal helical member (not shown-see Fig. 6). In place of the tube C a screw-type boring crown 30 (Fig. 13) can be fitted which has slots 31 to engage the pins 17 and a central tube through which water can be pumped. When the outer tube T has been sunk to the required depth the tube C or boring crown 30 is removed and a filling tube 20 (Fig. 7) is inserted and maintained concentric with the outer tube by rings 20b. The upper end of the filling tube 20 has a flange 22 which is supported on the top edge of the outer tube T through a layer of resilient material. A clip 25 is provided for connection of a vibrator. In use the filling tube is let down to a point just above water-level and the lower end is made water-tight with a concrete plug before the tube is lowered to its final position just above the bottom of the bore Reinforcement A comprising a base-plate 28, to which are welded longitudinal rods, is then lowered through the filling tube and drives out the plug. The filling tube and outer tube are then raised simultaneously as concrete is fed in through the hopper 26.