DRILL STRING FOR ERECTION OF BORED PILE IN SOIL-CEMENT CLADDING Russian patent published in 2020 - IPC E02D5/34 

FIELD: construction.

SUBSTANCE: invention relates to construction, namely to erection of bored piles in close proximity to standing buildings and structures, and can be used in formation of pile foundations in weak soils, jetting technology can also be used for strengthening weak soils with erection of bored piles. Drilling string for construction of bored piles in soil-cement shell, consisting of a set of in-series hermetically connected to each other collapsible hollow screws, in which from below the first hollow auger there is a drillable tool, above which there is a releasable dispensing element with jet forming nozzles for cementation, a drill string drive spindle, equipped with a system of sensors detecting change in drilling strength depending on strength characteristics of the drilled rocks, signal from which is supplied to control unit of complex of equipment for preparation and supply under high pressure of water-cement solution from pump unit to dispensing element with jet-forming nozzles. Dispensing element is installed in mounting seats of second bottom of hollow screw, in which there are side windows for jet-forming nozzles of dispensing element, which is mechanically connected for extraction of drilling tool. Along the axis of the drill string inside the hollow augers there is a central pipeline for supply of cement solution to the dispensing element, the central pipeline is rigidly fixed from above on the dispensing element for possibility of its extraction and the drilling tool from the drilling column, value of pressure P of the water-cement solution from the pump unit to the dispensing element with jet-forming Nozzles are determined by the given relationship. Time reserve required for processing information on properties of soils, detecting the extent of areas of low mechanical properties of the massif, formation of a command solution for correcting the carburising mode and switching to carburizing in the new mode, which is calculated in the complex of equipment control unit, is determined from the given relationship. Time for determination of length of areas with reduced or increased mechanical properties of massif T₁ is determined by the given relationship. Time for formation of command solution for correction of cementation mode and transition to cementation in new mode T₂, depending on length of located inside the hollow auger supply lines of high-pressure water-cement solution from pump unit to dispensing element, is determined by the given relationship.

EFFECT: technical result consists in reduction of construction time of bored pile in soil-cement cladding with improvement of its strength and bearing properties in weak soils.

1 cl, 6 dwg