RU2713822C1 - Installation method for a driving pile in a perforated mantle pipe - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the field of construction, in particular, to methods of construction of driven (pushed) piles in perforated tubes-shells with a broadened base, mainly in weak wet, waterlogged clay soils. Method of driving a driven pile in weak wet and waterlogged soils consists in the fact that a casing pipe with a lost shoe-punch is immersed into the ground with formation of a well with partial immersion into the bearing layer of soil. Widened base is formed by tamping of hard ground material in the lower part of the well formed in the bearing layer of soil. Perforated tube-shell is immersed, loose material is filled, casing is removed. Reinforced concrete pile is immersed into perforated pipe-shell so that local broadenings from loose material and possible compacted zones of soil on sections of holes location are formed on side surface of perforated pipe-shell in surrounding soil. Dipping of the perforated shell tube is performed outside the casing pipe. Bulk ground material backfilling is carried out in casing pipe with filling of loose soil material of perforated pipe-shell at extraction of casing pipe.

EFFECT: technical result consists in improvement of reliability to ensure maximum bearing capacity on side surface of pile within upper layer of weak wet and damp soil, reduced labor input and expanded field of application of proposed technical solution on soil conditions.

4 cl, 4 dwg

Description

The invention relates to the field of construction, in particular to methods for increasing the bearing capacity of driven (pressed) piles in punched (pushed) wells with a broadened base along their lateral surface, mainly in weak, moist and waterlogged clay soils.

Known methods of arranging rammed piles in weak moist and waterlogged soils, including punching (punching) wells with a casing with a lost shoe to the underlying bearing layer of the soil, filling the casing with cast concrete with reinforcement and its extraction (Ganichev I.A. Artificial foundation and foundation . - 3rd ed., Revised and enlarged. - M .: Stroyizdat, 1981; STO 36554501-018-2009. Organization standard. Design and construction of pile foundations and compacted foundations from rammed piles in punched wells. Research Center "Stroy telstvo ". - 2010; SP 24.13330.2011. Pile foundations. M. 2011; Guide for the design of pile foundations / NIIOSP named after N.M. Gersevanov Gosstroy of the USSR. - M: Stroyizdat, 1980 with additions in 2017).

The main disadvantages of the proposed technical solutions are the low bearing capacity (or even its additional reduction) of the piles along the lateral surface within the bedding of layers of weak (e.g. biogenic) moist and waterlogged clay soils, as well as the relatively high complexity and duration of the set strength of the cast concrete mixture used.

To one extent or another, an increase in the bearing capacity along the lateral surface is achieved by the method of pile construction according to patent RU 2186905, which includes the formation of a well, immersion in it at the same time of the external perforated left and internal continuous-stage extractable pipe, the supply of hardening material through the inner pipe, and the gradual formation by tamping of broadenings from the hardening material first under the lower edge of the outer pipe, and then the pile shaft with the simultaneous formation of local broadening along its lateral surface and in the region of the openings by moving or removing the inner tube.

The main disadvantages of the above method of pile construction are: some uncertainty in calculating the bearing capacity of the pile along its lateral surface in weak, waterlogged, and even more so saturated soils; low efficiency of the device for local broadening of hardening material by ramming with a flat bottom along the lateral surface of the outer perforated pipe; the duration of the set strength of the hardening material to the required strength, etc.

Pile foundations from driven prismatic, pyramidal, club-shaped and other piles are known and widely used in various soil conditions (SP 50-102-2003. Design and construction of pile foundations. Gosstroy of Russia. M. 2004; SP 24.13330.2011. Pile foundations. M 2011; Guidance on the design of pile foundations / NIIOSP named after N.M. Gersevanov Gosstroy of the USSR. - M .: Stroyizdat, 1980 with the latest additions in 2017).

The main disadvantages of foundations from driven piles are: the almost complete absence of bearing capacity or even its decrease along the lateral surface within the thickness of weak moist and waterlogged soils; relatively low bearing capacity when their ends are supported on underlying soils with a sufficiently high compressibility.

Closer to the proposed technical solution is a method of driving a driven pile in a drilled well in weak water-saturated soils (RU 2634912 C1, publ. November 28, 2017, paragraph 7 of the claims), including, with some interpretation, punching or forcing a well by a casing with a lost shoe - a punch in the lower part, having an internal cavity open at the top, into which, after the formation of the well, an expander shoe is installed, hard soil material is poured into the casing in its lower part, and the pipe is raised to a high at the proposed backfill, the formation of a broadened base is carried out by tamping hard soil material using an inventory pile equipped with a removable tip, and then bulk material is poured into the casing or loose and hard soil material alternately, the casing is removed to fill the casing with its entire height filled with material in the pipe, after which the reinforced concrete pile is immersed in the well with the formation of a possible additional compacted zone around the well.

The main disadvantage of this technical solution is the low efficiency of increasing the bearing capacity of piles within the upper layer of weak moist and waterlogged soils along its lateral surface, including due to an increase in the moisture content of the backfill material at the border with the pile material after removing the casing.

Closest to the proposed technical solution (prototype) is a method of driving a driven pile in a drilled well with a widened base (RU 2678172 C1, publ. 01/23/2019, paragraph 2 of the claims), including with some interpretation: phased formation of a widened base from rammed hard soil material (usually from rubble, gravel, hard concrete, etc.) in the bearing soil layer; installation in the casing of a perforated shell pipe into which loose or alternately loose and hard ground material is poured; the casing pipe is removed, and then the reinforced concrete pile is immersed in the filled perforated sheath pipe with the simultaneous formation of local broadening along its lateral surface at the locations of the holes and a possible additional compacted zone.

The main disadvantages of this technical solution are: low reliability of unhindered extraction of the casing due to the possible collapse of the backfill soil through the holes in the pipe and filling it with a space (gap) between the walls of the casing and the perforated sheath before immersion in it and therefore the need to carry out additional measures to eliminate the dumping of soil backfill; low efficiency of increasing the bearing capacity of piles within the upper layer of weak moist and waterlogged soils along the lateral surface of the shell pipe due to the formation of local broadening along its contour due to the presence of a gap gap between the walls of a punched (pushed) well and a perforated shell pipe and thereby increasing the complexity due to the implementation of additional measures related, for example, to the need for repeated immersion of the casing with a self-opening tip wipe the pipe with holes, fill it with loose ground material and remove it, in this connection, the scope of the method in question is also limited by the ground conditions.

The technical problem of the invention is the elimination of the above disadvantages of the prototype, namely: ensuring the unhindered extraction of the casing from the well; increasing the efficiency of increasing the bearing capacity of the pile along its lateral surface by eliminating the gap between the walls of the perforated shell pipe and the punched (pushed) well after removing the casing and, therefore, reducing the complexity by eliminating the need for additional measures to prevent filling of the gap and even in some cases, to eliminate and remove backfill soil from the gap, as well as expanding the scope of application on soil conditions and thereby increasing efficiency whole.

The indicated technical problem is solved by the method of driving a driven pile, which consists in immersing a casing pipe with a lost punch shoe into the soil to form a well with partial immersion in the bearing soil layer, forming a widened base by ramming hard soil material into the lower part of the well formed in the carrier layer of the soil, immersed in the perforated pipe-shell, fill in loose bulk material, remove the casing, immersed in a perforated pipe-shell reinforced concrete I pile with the formation on the lateral surface of the perforated sheath pipe in the surrounding soil of local broadening from bulk material and possible compacted soil zones at the hole locations, while, unlike the prototype, the perforated sheath pipe is immersed outside the casing, filling in loose soil the material is carried out into the casing with the filling of loose ground material perforated pipe shell when removing the casing.

In addition, the immersion of the perforated pipe-shell can be carried out with the completion of its end in a widened base, using a perforated pipe-shell equipped with a rim-nozzle with a cutting edge.

If necessary, to increase the bearing capacity of the piles after removing the casing pipe, the casing pipe with a self-expanding tip is immersed in the filled perforated shell pipe, filled with loose ground material and removed, and then clogged (immersed) in the perforated pipe shell of the reinforced concrete pile .

In addition, it is advisable to use environmentally friendly industrial wastes that are not prone to decay and are close in particle size distribution to sandy soils as loose ground filling material with appropriate justification.

The technical result achieved by the invention is to exclude the possibility of backfill soil falling into the gap between the casing and perforated pipes, as well as to eliminate or minimize the possibility of the formation of a cavity gap between the walls of a punched (pushed) well and a perforated shell pipe. This result is achieved due to the fact that the perforated pipe-shell is immersed not inside the casing, but outside. Thus, filling the gap between the casing and perforated pipes is excluded, and thus unhindered extraction of the casing is ensured. In addition, a cavity-gap is not formed between the perforated pipe and the walls of the well due to the possibility of immersing it close to the wall of the punched (pushed) well or minimizing it and thereby increasing reliability to ensure the required load-bearing capacity of the pile along the side surface.

Due to the immersion of the perforated shell pipe outside the casing, reliability significantly increases to ensure the maximum possible bearing capacity along the side surface of the pile within the upper layer of weak moist and waterlogged soils, labor intensity is reduced, and the scope of the proposed technical solution for soil conditions is expanded compared to the prototype for due to the exclusion of additional measures to exclude possible soil failure from the openings of the pipe-shell reliable involvement in joint work with local broadening from loose or hard soil material of the surrounding soil of natural composition, including in adverse soil conditions with low values of physical and mechanical characteristics.

As the pipe shells, as in the prototype, it is advisable to use used metal, polymer, etc. casing pipes, and as bulk material - environmentally friendly industrial waste not prone to decay and close in particle size distribution to sandy soils (burnt earth, steelmaking slags, etc.).

The proposed method is illustrated by drawings, which show the sequence of technological operations for the device of local broadening and possible sealing zones along the side surface of the pipe-shell in areas with holes.

In FIG. 1 shows a well in which a casing with a partial pinching of its end in the upper part of the formed broadened base from hard ground material in a supporting underlying soil layer of natural composition and loose ground material sprinkled into it.

In FIG. 2 - a well with a perforated shell pipe partially immersed in a broadened base outside the casing.

In FIG. 3 - a well with a reinforced concrete pile immersed in a perforated shell pipe filled with bulk material with a partial immersion of its end face in the broadened base after removing the casing with the formation of local broadening from bulk material and possible zones from compacted soil around the side surface of the shell pipe in sections with holes.

In FIG. 4 - section AA in FIG. 3 on an enlarged scale of a reinforced concrete pile immersed in the bulk material of the backfill of the perforated sheath pipe, with local broadening and possible compacted zones of natural soil along the outer contour of the sheath pipe (compacted soil zones are not shown conventionally).

In the drawings, the following notation:

1 - inventory casing;

2 - shoe punch;

3 - punched (pushed) well;

4 - the upper boundary of the bearing layer of soil;

5 - a possible compacted soil zone in the surrounding soil of natural composition;

6 - shoe expander;

7 - widened base of hard soil material;

8 - filling of granular soil material;

9 - perforated pipe-shell installed on the outside of the casing 1;

10 - holes in the pipe-shell 9;

11 - driven (pressed) precast reinforced concrete pile;

12 - local broadening of bulk material along the lateral surface of the perforated pipe-shell 9.

The method of driving a driven pile in a perforated pipe-shell with a widened base is as follows.

Submerge the casing 1 with the lost shoe punch 2 with the formation of the borehole 3 to a predetermined (calculated) depth with partial immersion in the carrier layer 4 of the soil and with the formation around the borehole 3 of a possible compacted zone 5 in the natural soil. Then, a broadened base 7 is formed over the expander shoe 6 from rammed (or compacted) gravel approximately to the upper boundary of the bearing soil layer 4. Formation of the broadened base 7 is carried out in a known manner by ramming hard soil material (gravel, gravel, concrete mix, etc. .) in the lower part of the well, punched (pushed) in the carrier layer 4 of the soil, for example, as described in patents RU 2634912, RU 2678172, RU 2685719. After that, pour into the raised casing 1 above the formed widened base 7 particulate precoat material (e.g., gravel dropout) 8 (FIG. 1).

Outside the casing 1, it is immersed coaxially with the gap with the smallest possible gap from the borehole wall 3 or a closely perforated pipe-shell 9 with holes 10 located as shown in FIG. 2, staggered or otherwise. The casing pipe 9 has a cutting edge at the end or is provided with a rigid rim-nozzle at the end to ensure possible finishing (immersion) of the end of the casing pipe 9 into the upper part of the formed broadened base 7 to a depth of 10 cm or the state of “failure” with a smaller finishing depth , or by calculation, by analogy with the patent RU 2640467 (see Fig. 2).

The casing pipe 1 is removed while filling the perforated shell pipe 9 with the holes 10 with loose ground material 8, after which the precast reinforced concrete pile 11 is driven (immersed) into the shell pipe 9 filled with the loose ground material 8 with the simultaneous formation of local broadening at the locations of the openings 10 12 from compacted loose ground material 8 and a possible additional compacted zone 5 in the soil of natural composition (Fig. 3).

In FIG. 4 shows a section AA in FIG. 3 on an enlarged scale with the image of a perforated pipe-shell 9, a driven pile 11 in a compacted soil of a backfill 8 and local broadening 12 in the sections of the holes. The resulting compacted zone in the soil of natural addition along the outer contour of the pipe shell 9 in FIG. 4 conventionally not shown.

If necessary, to increase the bearing capacity of the piles 11 in the shell pipe 9 along its lateral surface after removing the casing 1, one or two times immersion in the soil of the backfill 8 of the casing with a self-opening tip (not shown conventionally in the drawings) is filled with similar material 8, removing it and then immersing it in the perforated pipe-shell 9 of the pile 11.

The perforated pipe-shell 9 is made of polymer, etc. materials, as well as metal, reinforced concrete, asbestos cement, etc. As an unrecoverable perforated sheath pipe 9, used casing pipes reinforced if necessary, for example, with steel bandages, which contributes to their disposal.

The minimum diameter of the pipe-shell 9, taking into account the holes 10 and the permissible deviations when immersing the piles 11, is taken to be at least 1.5-2 sizes (diameters) in the cross section of the driven or pressed piles 11, or is established experimentally, depending on the type of backfill material 8 .

The size and location of the holes 10 in the wall of the pipe-shell 9 is determined taking into account the optimum possible volume of pressed (compacted-compacted) into the surrounding soil of natural composition through the holes 10 of bulk material 8 when the pile 11 is immersed (driven), these and other parameters are established experimentally from due to the lack of such studies when installing driven piles in punched (pushed) wells with a widened base.

Claims (4)

1. The method of driving a driven pile in weak moist and waterlogged soils, which consists in immersing a casing pipe with a lost punch shoe into the soil to form a well with partial immersion in the bearing soil layer, forming a broadened base by ramming hard soil material into the lower part wells formed in the carrier layer of the soil are immersed in the perforated shell pipe, the bulk soil material is poured, the casing pipe is removed, and the submerged in the perforated pipe shell pile pile with the formation on the lateral surface of the perforated shell pipe in the surrounding soil of local broadening from bulk material and possible compacted soil zones at the hole locations, characterized in that the perforated shell pipe is immersed outside the casing, filling of the loose ground material is carried out in the casing pipe with ensuring the filling of loose ground material of the perforated pipe shell when removing the casing. 2. The method according to p. 1, characterized in that the immersion of the perforated pipe-shell is carried out with the completion of its end in a widened base, using a perforated pipe-shell equipped with a rim-nozzle with a cutting edge. 3. The method according to p. 1, characterized in that after removing the casing pipe, the casing pipe with a self-expanding tip is immersed in a filled perforated pipe-shell, filled with loose ground material and removed, and then immersed in a perforated pipe-shell of a reinforced concrete pile . 4. The method according to p. 1, characterized in that as bulk soil material use environmentally friendly, non-degradable industrial waste, close in particle size distribution to sandy soils.

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