RU2678251C2 - Method of creating broadening at end of screw pile - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the construction, in particular to the construction of pile foundations of buildings and structures, arranged in the ground, allowing for screwing. Method for creating an additional broadening at the end of a screw pile, screwed using a leader well, pre-filled with a fixing fluid, is proposed. Leader well is filled with a fluid that secures the soil around the screw pile after it is immersed in the soil and filled with a screw channel and then solidified.

EFFECT: technical result consists in increasing the bearing capacity of a screw pile, screwed up using the leader well, without increasing the diameter of the blade of the pile, reducing material consumption.

1 cl, 2 dwg

Description

The invention relates to the construction, namely: to the construction of pile foundations of buildings and structures arranged in soils that allow screwing.

In a screw pile, the function of the lower broadening is performed by a blade made of metal. A known method of increasing the bearing capacity of piles by increasing the diameter of its blades [1]. The main disadvantages of this method:

- sharply increase the effort required to screw the pile when immersing it in the ground (screwing force);

- sharply increases the volume of the screw channel, which is formed in the adjacent soil at the end of the screwing process and violates the continuity of the already compacted soil and through which soil moisture can reach the pile metal, accelerating its corrosion.

To reduce the screwing force at the place of immersion of the piles, a leader well is pre-drilled or punched with a diameter of 0.4-0.7 of the diameter of the pile and a length of 0.3-0.8 of the length of the pile [2]. A further increase in the diameter of such a well will lead to a decrease in the degree of compaction of the soil around the pile and the adhesion of the pile to the surrounding soil.

A known method of construction of a pile foundation, in which the leader well is pre-filled with a fixing solution [3]. When such a well is submerged, a fixed and sealed zone in the form of a hemisphere below and a truncated cone above it is formed under the fifth and around the pile shaft.

However, when a screw pile is immersed in this way in the region of the truncated cone, a spiral channel formed by the blade is also formed, which reduces the continuity and, consequently, both the total strength of the fixed and sealed zone and its adhesion to the pile shaft. It is necessary that the broadening at the end of the screw pile increases without the formation of a helical channel.

A known design of a screw screw pile [4], in which a screw channel formed by a screw blade located on the lower end side, is destroyed by the blades located above the pile shaft and made at an angle opposite to the angle of inclination of the screw blade. At the same time, these blades mix the soil around the table with a dry binder (formation of cement soil).

However, with this design, the blades made at an angle opposite to the angle of inclination of the helical plane sharply increase the screwing force. In this case, the already compacted soil structure around the wellbore is completely destroyed.

A method is needed to create broadening at the end of the screw pile, in which the screw channel is eliminated without destroying the structure of the compacted soil surrounding the pile shaft and increasing the screwing force. That is, in order to immerse the pile, a helical channel must be formed, and for continuous compaction of the soil around the shaft of the pile, it should not be formed.

Such a contradiction is resolved by self-service and phase transition techniques. That is, the liquid previously introduced into the leader well must have the volume necessary and sufficient not only to compact the soil around the pile shaft, but also to fill the screw channel. In this case, after solidification of the liquid, the screw channel should turn into a spiral anchor inside the compacted soil.

The purpose of the invention: to increase the bearing capacity of a screw pile, performed using a leader well pre-filled with a fixing fluid, without increasing the diameter of the pile blade, changing the structure of the pile, disrupting the compacted soil, and increasing the twisting force.

This goal is achieved by the fact that before immersion of the screw pile, the leader well is filled with liquid, which secures the soil around the screw pile, after immersing it in the soil and filling the screw channel with subsequent solidification of the liquid.

The proposed method of increasing broadening consists of the following stages:

- filling the leader well with liquid, in an amount necessary and sufficient to consolidate the surrounding soil and fill the helical channel;

- immersion of a screw pile into the soil, with a concomitant increase in fluid pressure in the leader's wellbore;

- injection of soil layers adjacent to the well leader with fixing fluid;

- filling with a fixing fluid of the screw channel formed by the blade of the screw pile;

- fixing the soil with liquid and hardening it in a screw channel.

The proposed method allows the use of substances that increase their volume after solidification.

The inventive method with its essential features can be repeatedly and in various ways, using various devices and materials, successfully implemented in practice to obtain the above result.

Example. A method of increasing broadening at the end of a screw pile is illustrated by the drawing in FIG. 1. Before immersion of the screw pile (1) with the blade (2), a concrete mixture based on expanding cement (4) is pumped into the leader well (3). Then the screw pile (1) is immersed in the ground (5) by screwing. At the same time, the pile itself and its blade play the role of a piston, which increases the pressure of the mixture in the leader well. Under the influence of such pressure, the mixture begins to penetrate (6) into adjacent soil layers (7).

At the end of the immersion process (Fig. 2) of the screw pile (1), the entire concrete mixture passes into the adjacent soil layers (7), and the screw channel (8) where the concrete mixture based on expanding cement:

- solidifying and expanding, compresses the soil particles, the body (1) and the pile blade (2) into a single broadening;

- fills the helical channel (8), formed in the thickness of the soil and solidifying additionally seals its walls due to its expansion;

- isolates the metal parts of the pile (1), including the blade (2), from the corrosive effects of soil moisture [5].

Information sources:

[1] Electronic resource: http://podomostroim.ru/svajnye-fundamenty-oblast-primeneniya/

[2] Electronic resource: http.//build.novosibdom.ru/book/export/html/391

[3] RF patent No. 2456408, IPC E02D 27/28

[4] Utility model of the Russian Federation No. 156641, IPC E02D 5/56

[5] RF Patent No. 2197668, IPC F16L 1/028

Claims (1)

A method of creating additional broadening at the end of a screw pile screwed using a leader well pre-filled with a fixing fluid, characterized in that the leader well is filled with a liquid that secures the soil around the screw pile after immersing it in the soil and filling the screw channel with subsequent solidification.

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