RU1768706C - Drill-lowering pile - Google Patents

Abstract

Usage: in the field of foundation construction, mainly in frozen soils. The pile contains a barrel, a tip and an expanded cylindrical insert. The trunk has a section of a regular polygon. A cylindrical insert is located between the barrel and the tip and has a height equal to 1.1 - 1.2 of the width of the side of the barrel. The tip is made with channels radially located on the outer surface. The depth and width of the channels is 0.1 to 0.2 of the diameter of the cylindrical insert, 4 silt.

Description

The invention relates to the field of foundation construction, and in particular to piling structures that are submerged in wells previously drilled in frozen or thawed soils.

There is a known joint including a cylindrical barrel having a constant cross section along the entire length, and a conical tip in the lower part of the trunk. The pile is immersed in a well pre-drilled in the soil, the transverse dimension of which is greater than the diameter of the cylindrical shaft by at least 100 mm. Before installing the pile, the well is filled 1/3 of its height with a soil solution that, when the pile is immersed, is displaced and fills the space between the walls of the well and the body of the pile, ensuring the joint work of the surrounding soil and the body of the pile,

The bearing capacity of the pile over the ground in this case is defined as the sum of the bearing capacity along the side surface of the pile and at the end. In this case, the end face bearing capacity of a pile is defined as the product of the projection of the pile cross-sectional area by the calculated soil resistance to pressure. In the known solution, the bearing capacity of the pile depends on the length of the cylindrical part of the body of the pile without taking into account the length of the tip and its cross section. Therefore, the bearing capacity of this pile is small.

A disadvantage of this design is that the soil solution under the tip increases in volume during freezing and the heaving forces resulting from it push the pile out of the well and thereby reduce its bearing capacity.

A pile is known including a prismatic trunk having a section of a regular polygon, a conical pointed corner tip and a cylindrical insert above the tip.

The disadvantage of such a pile is reduced, compared with the claimed, I bear (L

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general ability, since the tip in the pile is made sharp, when resting it on the bottom of the well, a stress concentration is created under its tip. This causes deformation of frozen soil under the tip, which leads to its uncontrolled precipitation. This, of course, reduces its bearing capacity. Therefore, when determining the bearing capacity of a pile, the length of the acute-angled conical tip is thrown out of the calculations, therefore, the bearing properties of the frozen soil of the base are not fully used, which also reduces the bearing capacity of the pile as a whole.

The aim of the invention is to increase the bearing capacity of piles.

This is achieved in that in a pile including a prismatic trunk having a section of a regular polygon, a conical tip and a cylindrical insert above the tip, according to the invention, the height of the cylindrical insert is 1.1-1.2 of the width of the side of the pile shaft. The tip is provided on the outer surface with radial channels, the depth and width of which is 0.1-0.2 of the diameter of the cylindrical insert.

The height of the cylindrical insert should be 1.1-1.2 of the width of the side of the pile shaft in order to create an equal-strength pile body structure and ensure equal load-bearing capacity on the material. If the height is less than 1.1 the width of the side of the pile shaft, then destruction of the concrete insert occurs, as the principle of equal structural strength will be violated, and the insert will not be able to absorb the increased load, which can just be set due to the new pile design.

Increasing the height of the cylindrical insert more than 1.2 of the width of the side of the pile shaft will lead to an unnecessary increase in the consumption of materials for the insert, but will not increase the bearing capacity of the pile.

Radial channels located to the entire height of the lateral surface of the conical or spherical part of the tip allow the remnants of drill cuttings and the solution to be removed from the end of the pile, moving it into the bosoms of the well, which makes it possible to lower the pile to the bottom of the well under its own weight.

However, in order for the drill cuttings and the solution from under the end of the pile to move freely through the channels, ensuring that the excess mixture is squeezed out from the end, the dimensions of these channels must also be optimal. After all, if part of the sludge and solution

nevertheless, it will remain under the end of the pile; there will be no snug fit of the tip to the bottom. Thus, the length of the channels and their area should be such as to ensure that the entire volume of drill cuttings and mud is displaced from the bottom of the well, namely, the width and depth of the channels is not less than 0.1 of the diameter of the cylindrical insert. However too broad and

deep channels are also impractical to perform, since this can again lead to excess mortar under the end of the pile and to the disruption of the equal strength ™ design of the tip. It can be destroyed, which naturally will lead to a decrease in the bearing capacity of the pile. Thus, it is proposed that the depth and width of the channels be no more than 0.2 times the diameter of the cylindrical insert.

In FIG. 1 shows a General view of the proposed piles with a cylindrical head, axonometric; in Fig.2 - the pile shaft with a cylindrical insert; in FIG. 3, 4 - the same, cross section.

The pile contains a prismatic barrel 1 having a section of a regular polygon (square), a tip 2, for example, in the form of a truncated cone, and is provided with an insert 3 located between the tip 2 and

the lower end of the pile 4 of the trunk 1 coaxially with its vertical axis.

The insert 3 is cylindrical, the height of which is 1.1-1.2 a, where a is the smallest cross-sectional size

prismatic trunk piles.

The tip 2 is provided with radial channels 7, the projection length of which I on the vertical surface of the well must be at least the height of the bottom of the well h2.

The depth and width of the channels is 0.1-0.2 of the diameter of the cylindrical insert,

The installation of the drilling pile is carried out as follows.

A prismatic barrel 1 with a cylindrical insert 3 and a tip 2 is immersed in a borehole 5 into a soil solution or drill cuttings 8, which then moves from under the tip 2 through radial channels 7 and fills the sinuses 9 between the walls of the pile and the borehole 5.

Pile with insert 3 and tip 2 after complete extrusion of drill cuttings and mud 8 from under the end of the barrel 1

the bottom 6 settles to the bottom and at the same time the sinuses 9 are evenly filled with the soil solution between the tip and the walls of the well 5, which increases the reliability of the end face 4 of the pile and the bearing capacity of the pile on the ground.

Claims (1)

The claims A drill hole including a prismatic shaft having a section of a regular polygon, a tip and an expanded cylindrical insert located coaxially with it between the tip and the lower end of the shaft, characterized in that, in order to increase the bearing capacity of piles mainly when erected in permafrost soils, the cylindrical insert is made with a height equal to 1.1-1.2 of the width of the side of the trunk, and the tip with channels radially located on the outer surface, the depth and width of which is 0.1-0 , 2 diameters of the cylindrical insert rtth f / l fll // I in