RU2602535C1 - Method of making rubbly ramming pile - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction, in particular, to methods of bored piles arrangement. Method consists in formation of well, its layer by layer filling with crushed stone with further compaction of each layer by immersion of rotating cylindrical-conical die with axial force, defined by enclosed formula.

EFFECT: technical result is increase of soil bearing capacity.

1 cl, 1 dwg

Description

The invention relates to the construction, in particular, to methods for bored piles.

A known method for the manufacture of injection piles in seasonally frozen ground (Patent for the invention of the Russian Federation No. 2150550), including the formation of a well, filling the well with cement-sand mortar to the level of freezing of the soil.

The disadvantage of this method is significantly lower bearing capacity of drilling piles compared to bored.

A known method of manufacturing a gravelly stuffed pile, selected as a prototype (Patent for the invention of the Russian Federation No. 2338032). The method consists in the formation of a well without excavation, layer-by-layer filling of the well with a rigid loose mixture, followed by compaction of each layer. Compaction is performed with full longitudinal force on the breech. The saturation of the bulk mixture is carried out until equilibrium occurs between the axial force on the pickup and the repulsion of the soil saturated with the mixture.

The disadvantage of this method is the uncertainty of the relationship between the diameter of the roll and the longitudinal force on it. With a small longitudinal force, compaction of the granular mixture may not be sufficient to transfer axial loads from the building to the ground, which will lead to excessive subsidence of the foundation. With an overestimated longitudinal force in the surrounding soil, decompression zones (cracks) may occur, which can also lead to a decrease in the bearing capacity of the base of the building.

The objective of the invention is to stabilize the properties of reinforced soil foundations with subsidence, swelling, quicksand and other properties, with a change in the diameter of the roll or axial load on it.

The problem is solved by well formation, saturation of the well with crushed stone with its layer-by-layer compaction. The well can be obtained by methods of excavation, for example by auger method, or without excavation, for example by rolling. Then the well is portioned saturated with crushed stone. The volume of each portion of the mixture is determined from the ratio

V _mixture = (0.5 ÷ 1.5) · V _stamp · k,

where V of the _mixture is the volume of the portion of the hard loose mixture;

V _stamp - the volume of a cylindrical-conical stamp;

k is the coefficient of compaction of the mixture.

Crushed stone is compacted by immersion of a rotating conical stamp with an axial force at which the specific resistance to immersion of the cone will be in the range from 1 to 4 MPa. The axial force is calculated by the formula

where F _axial - axial force, N;

R _beats - specific resistance to immersion of the cone in the range from 1 to 4 MPa;

d _stamp - the diameter of the cylindrical part of the stamp, m

The saturation of the bulk mixture is produced to the design level. Piles made by the proposed method provide a stable increase in the bearing capacity of soils due to the correspondence of the diameters of the dies to the axial loads transferred to them.

The proposed technical solution is illustrated by the drawing, where in FIG. 1 shows a structural diagram of a gravelly stuffed pile.

A method of manufacturing a crushed stone stuffed pile is shown as an example of a drilling machine based on an excavator weighing 18 tons with reinforcement of subsidence soil in the depth range from 3 to 5 m. First, the drilling machine passes the well by excavating, for example, by a screw method, with a diameter of 200 mm to a depth of 6 m. Then the screw is changed to a cylindrical-conical stamp (roll) with a diameter of 200 mm. After that, portionwise (from 30 to 40 l), 20–40 mm fractions of the bottom face and bottom section of the well are saturated with slag crushed stone. At the same time, each portion of crushed stone is compacted by immersion of a rotating stamp (rolling machine) with an axial load of 60 to 65 kN. Crushed stone is saturated to the surface during a period of 6 to 12 compaction cycles.

Claims (1)

A method of manufacturing a crushed stone stuffed pile, including the formation of a well by excavation or without excavation, filling the well with a stiff, loose granular mixture, followed by compaction of each layer, characterized in that the volume of the gravel is calculated by the formula
V _mixture = (0.5 ÷ 1.5) · V _stamp · k,
where V of the _mixture is the volume of the portion of the hard loose mixture;
V _stamp - the volume of a cylindrical-conical stamp;
k is the coefficient of compaction of the mixture,
compacted by immersion of a rotating cylindrical-conical stamp with an axial force selected from the calculation

where F _axial - axial force, N;
R _beats - specific resistance to immersion of the cone in the range from 1 to 4 MPa;
d _stamp - the diameter of the cylindrical part of the stamp, m,
and saturation with crushed stone is carried out to the design level.

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