SU1260449A1 - Pile - Google Patents

Description

The invention relates to construction and is intended for use when driving the foundations of buildings and structures from driven piles in areas composed of subsiding soils of the second type by subsidence.

The purpose of the invention is to reduce the energy intensity of the pile.

FIG. 1 shows, in an isometric view, a general view of a pile with a round bore, the cylindrical shell is shown for clarity in a disassembled form; in fig. 2, a pile submerged in the ground in a position prior to the appearance of subsidence in the layer of translucent soil, a vertical section; in fig. 3 - the same, upon completion of the subsidence deformation of the soil; in fig. 4 - top of the pile, vertical section; position A - after immersion in the ground before the appearance of subsidence, position B - the same, after subsidence of the soil and settlement of the shell by the amount of maximum subsidence of the soil of its own weight Snp.rp; in fig. 5 is a sectional view BB in FIG. four.

The SVA includes a barrel 1 and an outer cylindrical shell consisting of axially arranged sections, each of which is assembled from two semi-cylindrical elements 2.

On the section of the trunk 1 surrounded by the shell, protrusions are made in the form of solid clips 3 arranged in light-brown hairs, and the semi-cylindrical elements 2 forming the casing 2 are provided with ends with embedded parts 4.

The length of the trunk is assigned based on the calculation of the pile for the limiting states of the two groups, based on the need to immerse the lower end of the trunk into the layer of non-subsiding soils 5 to a depth that provides the required load-bearing capacity of the pile to the ground (without taking into account additional load by the loading friction forces), and limitation of pile draft to acceptable limits. The distance a between adjacent clips is not less than the total value, consisting of the size of the maximum soil subsidence of its own weight Snp.rp, thickness in the clips 3 and two thicknesses 2d, protruding ends of the embedded parts 4, i.e. .p -f bt -2d.

The length of the semi-cylindrical elements 2 is chosen for reasons of convenience of their manufacture, transportation and assembly; the size must be a multiple of a, that is, where n is an integer.

The full length of the shell L is assigned from the condition where H is the difference between two marks: the design mark of the bottom of the end cap or grillage on the pile and the elevation of the roof of the layer of non-subsurface soils, am is an integer. Accordingly, the size of L is also a multiple of a, since m-n-a.

0

Q 5

five

0

0

five

The outer diameter of the yoke 3 is greater than the clear distance between the protruding ends of the inserts 4, and between the yoke 3 and the inner surface of the shell there remains a minimum mounting clearance K, equal to 2-3 mm.

All parts of the pile — the barrel and the semi-cylindrical elements forming the shell — are prefabricated prefabricated products.

It is advisable to assemble the shell sections around the barrel and connect them together at the factory by welding the embedded parts of the semi-cylindrical elements it is possible to perform the pile assembly on the construction site.

The immersion of the collected pile is carried out in one technological cycle using standard piling equipment (not shown).

The pile is immersed in a leader well 7 pre-drilled in a layer of subsiding soil 6, the diameter of which is equal (with a tolerance downwards) to the outer diameter of the shell. The depth of the leader well is taken not less than L + 5lr.gr Under these conditions, it is possible to immerse the shell into the ground unhindered and facilitate its movement along the trunk when the soil subsides.

Leading the borehole lead installation of rotary drilling (not shown). The fastening of the borehole walls is not required, since the subsurface soils in their natural state (before soaking), have low humidity, high strength and cohesion, and hold vertical walls well.

Although the immersion resistance of the shell running along the leader well is insignificant, it is not zero. Therefore, the shell in the process of immersion under the action of the resistance of the soil on the lateral surface takes the upper position relative to the trunk. In this case, the embedded parts 4 are engaged with the holders 3 of the barrel, and the barrel, which is hammered. With blows of the hammer, it carries away the shell. The clips provide coaxial immersion of the barrel and shell.

The possible collapse of soil particles from the walls of the leader well in the process of piling does not matter for this design, since the bearing capacity of the pile is determined by the section of its bore submerged below the bottom of the well.

Lead until the tip of the barrel reaches the design mark, i.e. the barrel will be immersed in the non-subsurface soil to the design depth, and the shell will be entirely in the subsurface layer. At the end of the piling, a gap C is formed between the barrel clips and the inserts, the value of which is equal to the magnitude of the elastic failure of the pile.

From this moment on, the working function of embedded parts, 4, which is the only non-durable component of the structure, ends. Their further state does not affect the work of the pile during its entire service life. This achieves equal to the durability of all structural elements on which its reliable operation during the operation period depends.

The essence of the design operation is as follows.

The payload from the building or structure is transferred to the bearing non-deposit soil 5 through the trunk 1. In this case, the upper part of the trunk, which is within the subsiding depth of the soil 6 and surrounded by a shell, serves only to transport the specified load to the lower part, immersed in non-sinking ground.

When developing subsidence causing sedimentation of the near-thawed soil mass and the emergence of a loading (negative) friction force on the soil contact with the side surface of the shell, these forces act only on the shell that settles, freely moving down along the pile shaft. This eliminates the effect of loading friction forces on the pile shaft and eliminates the harmful effect of subsidence on the bearing capacity of the pile on the ground.

The maximum sediment of the shell under the action of the forces of the loading friction cannot exceed the value of Zlr.gr, since in the lower layers of the subsidence, where the absolute values of the vertical deformations of the soil are small, the soil resists the immersion of the shell. For this reason, compliance with the designation of the dimensions of the structural elements of the pile condition .ri). + b-f2d guarantees the free running of the shell along the trunk in the most unfavorable cases of slump soil deformations possible in a given area, for example, during long-term intensive soaking of the entire subsidence stratum from above with hot water (in case of an accident). raising the level of groundwater (as a result of filling the nearby reservoir).

At the same time, the maximum carrying capacity of the pile on the material of the trunk is maintained, since the clips, resting on the shell, and through it on the surrounding soil mass, prevent the loss of longitudinal stability of the trunk in the area surrounded by the shell.

The penetration of soil from below or from above into the gap between the barrel and the shell is excluded both during the pile immersion process and during the operational period, due to the shape of the clips completely covering the gap. Soil ingress from the side is also impossible even after corrosion damage to the welds connecting the inserts 4, since the opening of the joints between the semi-cylindrical elements prevents the shell from being compressed by the surrounding ground in the horizontal plane, and the compressive forces in the shell body created by the opposite action of the loading force in the vertical plane friction in the upper zone of the subsidence and the resistance of the soil to the immersion of the shell in its lower zone.

For large strata of subsiding soils, the pile shaft can be made composite - either of the same diameter along the entire length, or with the lower part of a larger diameter (not shown). Docking of the upper and lower parts of the barrel can be carried out by any of the known methods, for example, using a welded, bolted, collet, stakannogo and glue joint (not shown).

It is also possible to make the barrel not round, but square, while preserving the shape of the clips and the shell. The most expedient technology for the manufacture of pile elements is centrifugation (this also applies to a square barrel).

A variant of constructive making of the pile can also be used, in which the lower part of the trunk is made of monolithic concrete directly in the ground by free dropping the concrete mix into the leader well, drilled in this case to the design mark of the lower pile shaft in the non-subsurface soil layer, and the upper part The barrel assembly with the shell is immersed in the well before the bottom of the barrel is sunk into the monolithic concrete of the lower part (not shown).

WIG

FIG. if

FIG. five

Compiled by G. Lutsenko

Editor A. GulkeTechred I. VeresKorrektor M. Demchik

Order 51197/25 Circulation 641 Subscription

VNIIPI USSR State Committee

for inventions and discoveries

113035, Moscow, Zh-35, Raushsk nab. 4/5

Branch PPP "Patent, Uzhgorod, st. Project, 4

Claims (1)

PILET, immersed in subsiding soils of the second type, including a trunk with protrusions on the side surface, arranged in tiers, and an outer cylindrical shell placed around the trunk with the possibility of free movement along it, characterized in that, in order to reduce the energy intensity of immersion, the protrusions of the trunk in each the tier forms a continuous cage, and the shell is made up of composite sections located one above the other, each of which consists of two semi-cylindrical elements with embedded parts on the upper and lower m the ends facing the axis of the barrel and protruding beyond the inner surface of the semi-cylindrical elements, the outer diameter of each continuous cage exceeds the distance in the light between the protruding ends of the opposite embedded parts of each section, and the distance between adjacent cages is not less than the total maximum subsidence of the soil from its own weight, the thickness of the cage and the two thicknesses of the protruding ends of the embedded parts, and the length of each <jg of the semicylindrical element and the total length of the shell are multiples of this value no. SU ,,,, 1260449