RU2241098C1 - Method for increasing load-bearing capacity of cast-in-place pile - Google Patents

Abstract

FIELD: building, particularly building foundations of cast-in-place piles in powder-like clay ground.

SUBSTANCE: method involves drilling well, placing explosive charge in well, forming camouflet cavity and filling thereof with concrete. Installed in well is metal cylinder having annular groove with inclined sides. Explosive charge is located between groove sides to direct explosion products towards well wall and, as a result, to create sealed annular cavity in ground.

EFFECT: increased load-bearing capacity.

2 cl, 2 dwg

Description

The invention relates to the construction of pile foundations from bored piles and can be used in their construction in dusty clay soils in a refractory or soft plastic consistency.

When driving piles into the soil as a result of its displacement from under the edge of the pile, the surrounding area is compacted. In bored piles this area is absent. Therefore, to increase bored piles, additional measures are carried out in order to increase their bearing capacity.

Known methods for enhancing the bearing capacity of piles largely depend on the bearing capacity of the soil under the lower end of the pile. In some cases, crushed stone or hard concrete with a thickness of 15-20 cm is poured to the bottom of the wells, which is compacted using a bit or a vibratory stamp (Metelyuk N.S., Shishko G.V., Solovyova A.B., Gruzintsev V.V. Piles and pile foundations, Kiev: “Budivelnik, 1977, p.204-205, fig. 4-4).

There is a method of erecting a stuffed pile with compaction of the base (ed. No. 165243, 5 E 02 B 5/38), which is the formation of a well, filling it with separate layers of soil material and ramming it into the bottom of the well and filling the well with concrete.

A known method of enhancing the bearing capacity of piles by increasing the compaction zone along the entire length of the pile with a directed explosion (RF patent No. 2081240), IPC 7 E 21 D 1/00.

An increase in the load-bearing capacity of the piles is achieved by forming camouflage broadening under the lower end of the pile using a mechanical expander, the use of which is possible only in soils of a refractory consistency (Kosterin E.M. fig. 7.22; 7.25).

The disadvantages of the considered methods are:

- the inability to control the quality of work performed;

- the use of sophisticated equipment;

- in the presence of weak soils with a disturbed structure, before the filling of wells with concrete, their walls will collapse;

- with a high level of groundwater it is necessary to organize a water reduction.

Closest to the proposed invention is a method of creating camouflage broadening by means of an explosive charge explosion (Shtol T.M., Telichenko V.I., Feklin V.I. Technology of construction of the underground part of buildings and structures. M: Stroyizdat 1990, p.172 -176, Fig.7.63a), including well drilling, placement of a concentrated explosive charge at the bottom of the well. After the explosion, a spherical camouflage broadening forms at the bottom of the well. The disadvantages of this method are:

- low utilization of the energy of the explosion due to the free exit of the explosion products through the borehole into the atmosphere, therefore, an intense shock wave does not have time to fully form in the soil. Such parameters of shock waves as the maximum pressure at its front and its momentum are insufficient for complete compaction of the base soil;

- significant seismic effects in the explosion on the surface of the day, since the charge is concentrated, not flat;

- if the center of charge does not coincide with the axis of the well, then the spherical camouflage broadening is shifted from the axis of the well, which reduces the bearing capacity of the piles;

- complicates the creation of several broadening along the length of the well.

The objective of the invention is to increase the bearing capacity of a bored pile by increasing the size of the area of bearing on camouflage broadening, located along the length of the well.

This goal is achieved in that in a method of enhancing the bearing capacity of a bored pile, including drilling a well, installing an explosive charge in it, forming a camouflage cavity and filling it with concrete, according to the invention, a metal cylinder is installed in the well, having an annular recess with inclined faces between which are placed explosive charge to direct the explosion products towards the walls of the well and create a compacted annular cavity in the ground.

The required number of camouflage cavities can be performed along the length of the well.

The essence of the method of increasing the bearing capacity of piles in dusty clay soils is illustrated by drawings, where:

figure 1 shows a longitudinal section of a cylinder with a explosive charge;

figure 2 - arrangement of camouflage cavities along the length of the well.

In the well 1, a metal cylinder 2 is placed, having an annular recess 3 with inclined faces 4, between which an annular charge BB 5 is placed. The lateral inclined faces 4 of the cylinder 2 are guides of the explosion products towards the walls of the well 1, creating a compacted annular cavity 6 in the soil 7.

The proposed method is implemented in the following way.

A well 1 is drilled, in which a charge BB 5 is placed between the inclined shelves 4 of the annular recess 3, which, when the charge 5 explodes, is the guide of the explosion products towards the side of the well 1, creating a compacted annular cavity 6 in the soil 7.

After creating the required number of cavities along the length of the well 1, it is filled with concrete 8.

The effectiveness of the construction of bored piles is achieved by reducing seismic impact, increasing the bearing capacity of piles, reducing the number of piles and explosive consumption, which allows to increase the load on the foundation and increase the stability of buildings and structures.

Claims (2)

1. A method of enhancing the bearing capacity of a bored pile, including drilling a well, installing an explosive charge in it, forming a camouflage cavity and filling it with concrete, characterized in that a metal cylinder is installed in the well having an annular recess with inclined faces between which an explosive charge is placed to direct the products of the explosion towards the walls of the borehole and create a compacted annular cavity in the ground. 2. The method according to claim 1, characterized in that the required number of camouflage cavities is performed along the length of the well.

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