RU2582530C2 - Drive pile device in punched well with wider base - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction. Method for driving piles comprises formation of well filled without sealing with sealing soil and immersion into concrete pipe. Well is formed by punching with pile with a shoe-punch at bottom, over which then form a broadened base of layered backfilled and compacted hard soil material on top of which some sleep without compacting soil material, followed by immersion in it drop reinforced concrete piles and final formation of broadened a base in an upper portion thereof and compacted zone in lower part, and on side surface of a driven pile.

EFFECT: technical result is increasing load-carrying capacity, reducing time and increasing efficiency of use of pile foundations in punched holes.

7 cl, 6 dwg

Description

The invention relates to the field of construction, in particular to the construction of deep foundations from prefabricated (factory ready) driven piles in punched wells with a broadened fifth base, i.e. of the most common prismatic, circular sections, etc., in the practice of building construction, mainly reinforced concrete piles in subsiding soils with type I soil conditions, bulk, highly porous clay, sand, and other weak soils with reduced bearing capacity in their natural or technogenic composition.

Currently, driven prismatic, less often pyramidal, diamond-shaped and other piles are widely used in various ground conditions (SP 50-102-2003. Design and installation of pile foundations. Gosstroy of Russia. M., 2004; SP 24.13330.2011. Pile foundations. M., 2011).

However, these piles have the following disadvantages, the main of which are:

low bearing capacity of piles in weak and other soils and especially when resting them on soils with high compressibility;

the impossibility of immersing piles in strong and dense - poorly compacting soils without leader wells, i.e. without pre-drilled (with drilling holes) wells and which are characterized by a significant (up to 2 times) reduction in bearing capacity along their lateral surface.

Known and widely used in various soil conditions, pile foundations from rammed in punched wells, as well as drilling piles, performed:

a) using a pneumatic punch followed by filling the well with a rigid concrete mixture and re-immersing a pneumatic punch into it with the formation of piles with a diameter of up to 14-26 cm (Kazakov Yu.N., Bulankin NF, Stoyan Yu.F. Technology of packing piles with pneumatic punchers // Foundations, foundations and soil mechanics. - 1995, No. 1);

b) by immersing in the soil with a piling installation of a conical inventory pipe-punching core with a diameter on top of 0.4-0.6 m, down 0.05-0.15 m using piling equipment (Krutov V.I., Sorochan EA , V. Kovalev. Foundations of shallow laying. M.: Publishing house ASV, 2009); IN AND. Krutov, A.S. Kovalev, V.A. Kovalev. Design and construction of foundations and foundations on subsidence soils. - M .: DIA Publishing House, 2013). In loose clay soils, wells are filled with a rigid concrete mixture, followed by immersion of an inventory core pipe into it;

c) by arranging an enlarged base from hard soil compacted into the bottom of the well using special attachments for hoisting mechanisms or piling installations (STO 36554501-018-2009. Organization standard. Design and construction of pile foundations and compacted bases from rammed piles in punched wells Research and Development Center "Building", 2010; Krutov V.I., Kagay V.K., Glukhov BC Foundations of rammed piles in punched wells // Foundations, Foundations and Soil Mechanics, 2011, No. 2);

d) by hammering the casing on a cast-iron or reinforced concrete cone-lost shoe (Vibro piles and their modifications) to the required depth or design failure, installing the reinforcing cage and filling the pipe with plastic concrete mixture with the casing removed from the well using a towing device and a rope block or vibrator (Ganichev IA "The device of artificial foundations and foundations" - 3rd ed., revised and additional - M .: Stroyizdat, 1981);

e) by drilling wells to a predetermined depth and, as a rule, by not less than 1 m deepening into the underlying layer with increased strength and bearing capacity, camouflage broadening devices under a layer of cast concrete mixture, lowering a precast concrete pile into the well through broadening from the concrete mixture pressing it into the underlying bearing layer, filling the gaps between the pile and the walls of the well with soil, cast concrete mixture or other setting mortar (SP 50-102-2003. Design and construction of pile foundations. Gosstroy Ross II. 2004).

The main disadvantages of the above technical solutions, the above-named designs and methods of installation of pile foundations, respectively, in paragraphs "a" - "e" are:

- the limited scope of such piles due to the relatively small diameter of up to 0.14 and in some cases up to 0.26 m and the depth of the device up to 2-6 m, as well as the inability to perform in soils with interlayers or even lenses with increased density and strength and especially in the thickness of dense soils;

- incomplete use of the bearing capacity of soils under the pile end due to its small area not exceeding 0.002-0.018 m ² ; the need to use two types of concrete mix, namely, rigid concrete on a large aggregate to press it into the side surface of the well with the possible re-immersion of the punch core and cast on a small aggregate when concreting the pile shaft; the difficulty and often the impossibility of re-immersing the punch core in a well filled with a rigid concrete mixture in the presence of layers and lenses sufficiently strong and dense, including low-moisture clay soils; low bearing capacity of such piles in clay soils with high humidity, as well as in dense and low-moisture soils due to the lack of the ability to push hard concrete into the well walls;

- lack of special attachments for lifting and transport mechanisms and the need for its artisanal manufacture;

- relatively low bearing capacity on vertical and especially on moment and horizontal loads;

- almost complete exclusion in the transfer of load on the base soil along the lateral surface of the pile and along its entire length to vertical and horizontal loads, as a result of which these piles should be used only when cutting peat and other soils with peat layers in them, as well as in self-compacting from its own weight subsidence with type II soil conditions and unbreakable loose soils.

In addition, a common drawback of all the above foundations is a significant (up to 0.2-0.5 months) interruption in the work of the zero cycle, which is necessary to increase the strength of concrete of the printed piles to the required values, as a result of which the construction time is significantly increased.

The closest analogue to the claimed method is a method of constructing a pile foundation from driven piles on subsidence soils with type II subsidence, adopted as a prototype, from which it is known to arrange a pile foundation with the formation of wells, the axes of which coincide with the design position of the axes of the piles and filled with drainage material, while the piles are made with the possibility of soaking and immersion in wells, which form the entire depth of subsidence soil with deepening in the underlying non-subsidence soil. After filling the wells with drainage material, the area is surrounded around the perimeter of the structure, the area covered is covered with a layer of drainage material, soaking is carried out by pouring water on the surrounded area and holding for 15-30 days, after which the piles are immersed in the wells (SU 885446, 30. 11.1981 )

According to the method of construction of the pile foundation according to SU 885446, the following should be noted:

a) the foundation method under consideration applies only to subsidence soils with type II soil conditions in which subsidence of its own weight is possible, and the method according to the proposed application only to subsidence soils with type I by subsidence, i.e. in the absence of drawdown from its own weight;

b) in accordance with the previous ones (Guidelines for the production and acceptance of work when laying the foundations and foundations. NIIOSP named after N.M. Gersevanov. M: Stroyizdat. 1977; Krutov V.I., Galitsky V.G. Compaction of subsidence soils. M.: Stroyizdat, 1974) and the requirements that have been preserved to date (Manual on the design of foundations and foundations of buildings and structures (to SNiP 2.02.01-83). NIIOSPP named after NM Gersevanov. M: Stroyizdat , 1986) drainage wells should be performed by drilling with sampling of the soil without creating around and under them compacted ny zones. In cases of wells being drilled by punching and creation of densified zones around them, the filtration capacity of drainage wells is very significantly reduced, i.e. they will perform the function of reinforcing elements and restrain the intensity of soil compaction, therefore they are not effective;

c) in order to ensure the creation of compacted zones around and especially under the pile, in which an increase in the bearing capacity of the pile is achieved, it is necessary to reduce the soil moisture from full water saturation ω _s to a value close to the optimum humidity ω ₀ , usually equal to ω ₀ = ω _p ( ω _p - humidity at the boundary of plasticity). Such a decrease in humidity usually occurs within 10-20 days after the termination of soaking, i.e. only after this time should the submerged pile be immersed in the drainage well. In this connection, if the pile is immersed immediately after the soaking is stopped, when the soil is in a state of almost complete water saturation (degree of humidity S _r ≥0.8-0.9), then the pile will be immersed almost without compaction of the near-pile soil and mainly due to the expansion of the soil to the sides with a very significant rise of its surface around the well and partial softening of the soil around and under the pile.

Thus, from the time the drainage well is completed to the immersion of the driven pile according to SU 885446, it takes about 2-3 months. According to the proposed application, this time can be reduced, depending on soil conditions, to several (1-2) hours;

d) the implementation of drainage wells with their deepening into a non-subsiding underlying bearing layer according to SU 885446 inevitably leads to a decrease in the strength and deformation characteristics of these soils (especially with their clay composition) and thereby to a decrease in the bearing capacity of a pile to be driven in a subsequent one, as well as an increase in its length ;

d) SU 885446 does not indicate the limits of the change in the diameter of drainage wells, which can, to a greater extent than their depth, determine the effectiveness of increasing the bearing capacity of a driven pile.

The problem to which the proposed application is directed is to create a pile foundation device from driven piles in punched wells with a broadened fifth base, which would eliminate the above disadvantages.

The technical result achieved by the implementation of this method is to increase the load-bearing capacity of piles and the efficiency of pile foundations by using only one piling installation both when punching wells and by increasing the load-bearing capacity of piles by creating an expanded base from rammed-compacted hard ground material in the lower, and also, if necessary, in the upper part of the driven pile.

The specified technical result in the method of driving a driven pile, consisting in the formation of a well filled without compaction with compacting soil, and immersion in reinforced concrete piles, is achieved by forming a well by punching it using a pile with a punch shoe in the lower part, above which form a broadened base from layer-by-layer poured and compacted hard soil material, on top of which soil material is poured without compaction, followed by immersion in it with driven jelly reinforced concrete piles and the final formation of a broadened base in its upper part and compacted zone both in the lower part and along the lateral surface of the driven pile.

For punching a well, you can use an inventory pile with a tip having a lower cavity in which a punch shoe is located.

In addition, for punching a well, you can use a driven reinforced concrete pile with a removable tip having two cavities in its lower and upper parts, in which the upper part of the punch shoe and the lower end part of the driven pile are respectively located.

In order to maintain the integrity of a driven reinforced concrete pile in soils with dense or solid inclusions and a punch shoe during well formation, it is advisable to first punch the leader well.

In this case, the leader hole is punched with a steel inventory pile with a removable shoe of a smaller diameter than the diameter of the punch shoe.

To increase the bearing capacity of a driven reinforced concrete pile for horizontal and moment loads, a broadening of hard soil material is formed in the upper part of the driven concrete pile using a ramming template with an internal cavity, first by ramming the excavation pit with immersing the template around the pile head to the depth (1 -2) d of diameter d of the cross section of the punched well, followed by filling the pit pit with hard soil material and compacting it with the same template.

In addition, the well is punched in unstable water-saturated sand and clay soils with the casing, and after the formation of the broadened base, the well is filled with sand or loose ground material while the casing is removed from the well with vibration being applied to it if necessary.

The description of the proposed method is illustrated by drawings, where in FIG. 1 shows a well punched by a punch shoe inserted into the lower cavity, including a removable tip, an inventory pile immersed in the soil by a piling unit to a predetermined depth to form a compacted zone around the punched well; in FIG. 2 - a well punched by a driven reinforced concrete pile, for which a driven reinforced concrete pile in the lower part is equipped with a removable tip with two lower and upper cavities, into which respectively a shoe punch and a driven reinforced concrete pile fixed to the tip are inserted; in FIG. 3 - formed a broadened base from an indented pile of compacted hard ground material (crushed stone, gravel, hard concrete, etc.) rammed with the lower part of the tip after layer-by-layer filling and ramming (compaction) into the lower part of the well above the shoe punch of hard ground material a given volume to a given height; in FIG. 4 - a broadened base made of compacted hard compacted soil (crushed stone, gravel, hard concrete, etc.) formed by the lower part of the removable tip of the driven reinforced concrete pile after layer-by-layer filling and tamping-compaction into the lower part of the well above the hard ground punch shoe material of a given volume to a given height; in FIG. 5 - immersion of a reinforced concrete driven pile in a filled well without compaction of hard soil material (crushed stone, gravel, etc.) or local soil (sand, clay) on its entire upper part with the formation of additional zones of soil compaction at the widened base and along the lateral surface driven piles; in FIG. Figure 6 shows a broadening device made of compacted hard soil material in the upper part of a driven pile with a steel ramming template with an internal cavity to a depth of 1-2 diameters of a punched well after tamping the foundation pit, layer-by-layer filling and compaction in the resulting foundation pit-hard soil material.

Accepted designations:

1 - inventory pile;

2 - a tip with an internal cavity in the lower (end) part;

3 - shoe punch;

4 - punched well;

5 - compacted zone of soil around and under the punched well;

6 - broadened base of stamped-compacted hard ground material;

7 - compacted soil material along the lateral surface of a driven pile;

8 - additional compacted area after immersion-driving of reinforced concrete piles;

9 is a ramming template for forming a rammed foundation pit and compacting hard ground material 10 therein;

11 - driven reinforced concrete pile;

12 - removable tip with internal cavities in the lower (end) part and the upper part.

The method of driving a driven pile is as follows.

The well 4 is formed by punching an inventory pile 1 to a predetermined depth using a tip 2, including a removable one (nozzle), into the lower cavity of which a shoe punch 3 is inserted (Fig. 1).

In addition, under certain ground conditions, only one reinforced concrete pile can be used, for which a driven reinforced concrete pile 11 in FIG. 2 in the lower part is equipped with a removable tip 12 with two lower and upper cavities, into which respectively a shoe punch 3 and a driven reinforced concrete pile 11 attached to the tip 12 are inserted (Fig. 2). The cavities in the upper and lower parts of the removable tip 12 are performed respectively in shape and size of the upper part of the punch shoe 3 and the lower (end) part of the driven reinforced concrete pile 11. Moreover, the removable tip 12 is used only in the process of punching the well (see Fig. 2) and creating a widened base in the lower part of the well 4 from hard ground material (Fig. 4).

Well 4 is formed by punching it to a predetermined depth with an inventory pile 1 with a punch shoe 3 with taper angles of 25-90 ° inserted into the lower part of the tip 2 of an inventory pile 1 with a taper angle and shape similar to the upper part of the punch shoe 3, or driven reinforced concrete pile 11 with a tip 12, equipped with two cavities, in the lower part of which a piercing shoe 3 is inserted, and in the upper part - a driven reinforced concrete pile 11. After that, in the well 4 above the piercing shoe 3 they are poured layer by layer and rammed (compacted) ) hard soil material with the lower part of the tip 2 or 12 of inventory 1 or driven reinforced concrete 11 piles, respectively, to a height equal to at least 2-3 d - diameter d of the punched well 4 above the upper tip of the punch shoe 3 or to the state of failure with the formation of a widened base 6. Then, hard soil material or local soil (sand, clay, etc.) is poured into the borehole 4 to increase the bearing capacity along the side surface of the pile 11 without sand compaction, followed by immersion in the reinforced concrete borehole 4 hydrochloric piles 11 recessed in its hard soil material to a depth of at least 0.5 m (PO 50-102-2003. Design and construction of pile foundations. Gosstroy of Russia. 2004) or to the state of failure (at a shallower depth than 0.5 m) with the final formation of the lower broadened base 6 in its upper part and the compacted zone both in the lower part and along the side surface of the driven pile 11.

The sharpening angles of the punch shoe 3 are assigned to provide the greatest effect of compaction of the soil of the base in the lower part and the formation of a widened base 6 of rammed (compacted) hard soil material in the upper part, first with the tip 2 of the inventory pile 1 or the tip 12 of the driven reinforced concrete pile 11, and then in the process of immersion in it driven concrete piles 11.

To increase the bearing capacity of the driven reinforced concrete piles 11 for horizontal and moment loads, the compacted soil material 10 is broadened in its upper part (Fig. 6), for which a steel template-tamper 9 with an internal cavity is used when the foundation pit is tamped out (pit-pit) to a depth of 1-2 d of the diameter d of the well 4 (or according to calculation), then layer-by-layer hard soil material 10 is poured into it and compacted with a ramming tool 9 of the same piling unit to a compaction coefficient k _com ≥0.95 (V.I. Krugov, A. S. Kovalev, EI Shikhov. Experience in the application of rational structures and technologies in the construction of foundations and foundations in the city of Novorossiysk // Mechanization of construction. -1997, No. 12).

As the material of the punch shoe 3, for example, concrete (reinforced concrete), metal, or a combination of them with sharpening angles in the upper and lower parts within 25-90 °, diameter (cross section), taking into account the most common nomenclature of reinforced concrete piles, can be used. less than 35 cm, which, as experience shows, provides for punching wells depending on soil conditions with a diameter of 35-45 cm and the formation of a sealed zone with a diameter of up to 55 cm. A round or steel pipe can be used as a removable tip 2 or 12 a square shape in plan, which is provided with one lower cavity when using inventory piles 1 or two cavities in the lower and upper parts when using a driven reinforced concrete pile 11, made respectively in shape and size of the upper part of the punch shoe 3 and the lower part of the driven reinforced concrete pile 11, which are fastened in their lower part to the walls of the removable tip 2 or 12, for example, with bolts.

Before driving-diving inventory 1 or driving 11 reinforced concrete piles, the punch shoe 3 is installed in place of the future well, then the inventory 1 (or driving 11) reinforced concrete pile with a tip 2 or 12 with a lower cavity is lowered and immersed, for example, with a rod diesel - ground into the soil with the formation of a punched well 4 and a compacted zone.

In addition to the above, to increase the bearing capacity and provide the device:

- in unstable water-saturated sandy and clay soils, the wells are punched with a casing (not shown), and after extraction of an inventory or reinforced concrete pile, the wells are filled with sandy soil or loose hard soil material while the casing is removed with a winch cable from the pile driving machine from the pile driving unit to the pile driving unit if necessary, vibration after the formation of the lower broadening;

- in the presence of solid inclusions, for example, in bulk soils, the leader hole (not shown) is first punched with a steel inventory pile with a removable shoe, for example, the design of NIIOSP (Smorodinov MI and other Machines and equipment for the construction of foundations and foundations. - M .: Stroyizdat, 1985) of a smaller diameter, and then a pile with a punch shoe according to the proposed method of a larger diameter;

- punching a well, forming a broadened base, driving a pile using a guide metal plate with a hole in the center for a driving pile, for example, partially by analogy with the equipment for building foundations from driven blocks (V.I. Krugov, A.S. Kovalev, V.A. Kovalev, Design and installation of foundations and foundations on subsiding soils, Moscow: Publishing House ASV, 2013).

The most significant differences and advantages of the proposed method is the ability to:

- punching the well 4, forming a broadened base 6, immersing the pile 11 in the soil poured without compaction into the punched well 4 — hard ground material or local soil with a significant reduction in the time for constructing the pile foundation and creating compacted soil zones around and below the well with increased strength and deformation characteristics of soils;

- increase the bearing capacity of piles 11 (pile foundation) due to the device broadened base 6 (broadening) of stamped-compacted hard ground material in its lower and upper parts, respectively;

- in soils with solid inclusions, first use the punching of the leader well, including inventory steel piles with a removable shoe of a smaller diameter, for example, the design of NIIOSP (Smorodinov MI and other Machines and equipment for the construction of foundations and foundations. - M .: Stroyizdat, 1985), and then punching the well according to the proposed method with a larger cross-sectional diameter.

It should also be noted that the above differences and advantages of the proposed method can significantly (in general, up to 1.5-2 times or more) to reduce material and labor costs, time for the construction of pile foundations in comparison with the application of the above known technical solutions, and also to increase the reliability of the installation-driving of the shoe-punch at the bottom of the punched well by ensuring tight contact of its walls with the soil of the base and thereby the quality of the device of the lower broadened base.

Claims (7)

1. The method of driving a driven pile, which consists in the formation of a well filled without compaction with compacting soil, and immersion in reinforced concrete piles, characterized in that the well is formed by punching it using piles with a shoe-punch in the lower part, above which an expanded a base made of layer-by-layer filled and compacted hard soil material, on top of which soil material is poured without compaction, followed by immersion of a driven reinforced concrete pile into it and final ormirovaniem broadened base in its upper part and densified zone in the lower part and on the lateral surface of the pile to the pile. 2. The method according to p. 1, characterized in that for punching the well using an inventory pile with a tip having a lower cavity in which the shoe punch is placed. 3. The method according to p. 2, characterized in that for punching a well, a driven reinforced concrete pile with a removable tip having two cavities in its lower and upper parts, in which the upper part of the punch shoe and the lower end part of the driven pile are located, respectively, is used. 4. The method according to p. 1, characterized in that when the well is formed, the leader is punched first. 5. The method according to p. 4, characterized in that the leader hole is punched with a steel inventory pile with a removable shoe of a smaller diameter than the diameter of the punch shoe. 6. The method according to p. 4, characterized in that in the upper part of the driven reinforced concrete pile, a broadening is made of hard soil material using a ramming template with an internal cavity, first by ramming the pit-ditch with immersion in the soil of the template around the pile head to a depth (1 -2) d of diameter d the cross section of the punched well, followed by filling the pit-pit with hard ground material and compacting it with the same template. 7. The method according to p. 1, characterized in that the punching of the well in unstable water-saturated sand and clay soils is performed with the casing, and after the formation of the broadened base fill the well with sandy soil or loose ground material simultaneously with the extraction of the casing from the well with the application to her in necessary cases of vibration.

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