RU166517U1 - SCREW PILES - Google Patents

Abstract

1. A screw pile, including a cylindrical shaft, a tip with a spiral, characterized in that the cylindrical shaft of the pile is made with a length of 3001 mm to 4000 mm, the cylindrical shaft of the pile is made stepped, consisting of at least two sections made with decreasing to the tip with diameters from 325 mm to 141 mm, the tip with a spiral is made from 1001 mm to 1500 mm long, the spiral is made with a spiral pitch of 41 mm to 50 mm and the width of the spiral blade is from 11 mm to 20 mm, the thickness of the tip cone end is from 31 mm to 65 mm. 2. A screw pile according to claim 1, characterized in that at least two parts of the cylindrical shaft are provided with a spiral. A screw pile according to claim 1, characterized in that it is provided with a flange with a thickness of 11 mm to 20 mm with holes with a diameter of 16 mm to 50 mm. 4. A screw pile according to claim 1, characterized in that the flange is made in the form of a ring with round or oval holes. A screw pile according to claim 1, characterized in that the flange is made in the form of a disk with diametrically located holes and a central hole.

Description

The utility model relates to the construction, in particular, to the construction of pile foundations, and can be used for the construction of low-rise houses, modular buildings, bathhouses, terraces, greenhouses, hangars, pipelines, advertising structures, road signs and signs, noise screens, line supports lighting and communications, garden furniture, fences and fences, the bases of solar panels and wind generators.

A device for mounting an object in the ground is known. The device is hollow, contains a cylindrical part in which an object is installed (rod, pole, mast), an anchor part for fastening in the ground. The anchor part is formed in one piece with the cylindrical part, made cone-shaped, has at least two conical parts with different taper angles. The conical part of the anchor is provided with a spiral. At the top of the cylindrical part, a hole is made for mounting the fastener. (German Patent No. 9313258, IPC Е04Н 12/22, publ. 24.03.1994).

Known screw pile, including a cylindrical barrel 76 mm and a tip with a spiral. There is also known an embodiment of a screw pile, including a cylindrical shaft of the pile, made stepped, consisting of at least two sections made with decreasing diameters to the tip. There is also a known embodiment of a screw pile provided with a flange 8 or 10 mm thick with 12 mm holes. (Screw supports, http://glavzabor.ru/category3.php)

The closest technical solution to the claimed utility model is a screw pile includes a cylindrical shaft with a length of 700 mm to 3000 mm, a tip with a spiral with a length of 300 to 1000 mm, the spiral is made with a spiral pitch of 35-40 mm and a spiral blade width of 10 mm, end thickness tip cone is 25-30 mm. The cylindrical barrel can be made stepped, consisting of at least two sections with diameters decreasing towards the tip from 140 mm to 66 mm, and part of the barrel is equipped with an additional spiral. The pile can be equipped with a flange with a thickness of 8 mm to 10 mm with holes with a diameter of 10 mm to 15 mm, made in the form of a ring with holes or a disk with diametrically located holes and a central hole. (RF patent No. 117933, IPC E02D 5/56, publ. 10.07.2012)

A disadvantage of the known structures is the lack of adhesion to the base (soil), a narrow range of applications, i.e. An object can only be immersed in a pile; only one type of fastener can be used to immerse a pile.

The technical problem to which the claimed utility model is directed is to increase the reliability of the pile foundation by increasing the adhesion strength of the screw pile to the ground to create a stronger anchor effect.

The stated technical problem is solved in that in a screw pile, including a cylindrical shaft, a tip with a spiral, according to the proposed utility model, the cylindrical shaft of the pile is made with a length of 3001 mm to 4000 mm, the cylindrical shaft of the pile is made stepped, consisting of at least two sections made with diameters decreasing towards the tip from 325 mm to 141 mm, the tip with a spiral is made from 1001 mm to 1500 mm long, the spiral is made with a spiral pitch from 41 mm to 50 mm and the spiral blade width is from 11 mm to 20 mm, thickness The tip cone end is between 31 mm and 65 mm.

A screw pile is characterized by the following additional essential features:

- at least two parts of the cylindrical barrel are provided with a spiral;

- the screw pile is equipped with a flange with a thickness of 11 mm to 20 mm with holes with a diameter of 16 mm to 50 mm;

- the flange is made in the form of a ring with round or oval holes;

- the flange is made in the form of a disk with diametrically located holes and a central hole.

The technical result, the achievement of which is ensured by the implementation of the claimed combination of essential features, is to increase the adhesion strength of a screw pile with soil to create a stronger anchor effect.

The essence of the claimed utility model is illustrated by drawings, where

in FIG. 1 shows the graphs of the dependence "load-sediment piles" S = f (P) at sites No. 1, 2, 3, respectively (Appendix 1);

in FIG. 2 shows the graphs of the dependence “load-output piles” DV = f (PV) at sites No. 1, 2, 3, respectively (Appendix 1);

in FIG. Figure 3 shows in a graphical form the result of graphic processing of the data of excesses and deformations of the BAU Screw Foundations and soil (Appendix 1);

in FIG. 4, 5, 6, 7 are graphs of the dependence of the deformation of piles No. 1, 2, 3, 4 with a length of 2 m from the action of the horizontal load (Appendix 2);

in FIG. 8, 9, 10, 11 graphs of the dependence of the deformation of piles No. 1, 2, 3, 4 with a length of 2.5 m from the action of the horizontal load are presented (Appendix 2);

in FIG. 12, 13, 14, 15 are graphs of the dependence of the deformation of piles No. 1, 2, 3, 4 with a length of 3 m from the action of the horizontal load (Appendix 2).

A screw pile includes a cylindrical barrel and a tip with a spiral, which are hollow.

The cylindrical shaft of the screw pile is made with a length of 3001 mm to 4000 mm. Moreover, the cylindrical shaft of the screw pile consists of at least two sections made with diameters decreasing towards the tip from 325 mm to 141 mm. The proposed implementation makes it possible to use pipes with a diameter of 141 mm to 325 mm for the manufacture of a pile foundation; pipes with a diameter of 219, 325 mm are preferred, which allows installing on it from road signs and signs, advertising structures to baths, greenhouses and low-rise buildings. At least two parts of the cylindrical barrel are additionally provided with a spiral.

The tip of the screw pile is made in lengths from 1001 mm to 1500 mm. The length of the tip is selected depending on the reinforced structure in accordance with the requirements of reliability of fastening in operation. The thickness of the tip cone end is from 31 mm to 65 mm, which reduces the complexity of its immersion in the ground.

The spiral is made with a spiral pitch of 41 mm to 50 mm and a spiral blade width of 11 mm to 20 mm.

For different types of soils, a wider range of pile shaft lengths is needed. The proposed implementation of a screw pile with the indicated intervals of the geometric dimensions of the structural elements increases the true area of adhesion of the pile with the ground, which increases the anchor effect, thereby increasing the reliability of the pile foundation.

For fixing supports in a screw pile, known fixing means are used. For example, nuts for fastening bolts are welded to the pile. And the support, for example a pipe, when installed in a pile, is fastened in it with the help of bolts.

The pile is additionally equipped with a flange from 11 mm to 20 mm thick with holes for bolts or studs. The holes are made with a diameter of 16 mm to 50 mm. The flange can be made in the form of a ring with round or oval holes or in the form of a disk with diametrically located holes and a central hole. For example, the flange can be made with a diameter of 220 mm with a distance between the centers of diametrically located holes 167 mm. The diameter of the central hole can be made 24 mm for a bolt with a thread of 24 mm. The presence of a flange simplifies and facilitates maintenance work on the installation of the foundation, ensures the stability of the structure. The various flange options available expand the range of application of piles.

When carrying out calculations and experimental work, the applicant concluded that the proposed size range of piles provides a reliable installation of the structure on various soils.

Reliability (bearing capacity) of the pile foundation

depends on a number of factors that are taken into account when choosing the size of screw piles and the depth of immersion of piles, in particular on the total mass of the structure as the sum of all the loads acting on the foundation, snow and payload depending on the purpose and location, strength and deformation characteristics of soils and other factors.

As an example, table 1 with the physico-mechanical properties of the inventive screw piles. Table 1 shows the static loads obtained as a result of field tests performed according to GOST 5686-94, SNiP 2.02.03-85, SP 50-102-2003, as well as SP 50-102-2010.

To convert from ton-force (CU) to kilonewtons (kN), a coefficient of 9.80665 (or 10) must be applied.

As evidence of the reliability of the inventive screw piles, Appendices 1 and 2 present the results of research tests of screw piles for pulling and horizontal loads in natural (field) conditions, which were carried out in conjunction with Altigov State Technical University Department of Engineering and Construction Engineering ("Foundations, foundations, engineering geology and geodesy") Barnaul and GeoProektStroyAltay LLC in accordance with the recommendations for the design of BAU screw piles for civil, industrial and engineering structures.

The implementation of a pile tip equipped with a spiral from 1001 mm to 1500 mm long with a spiral pitch of 41 mm to 50 mm and a spiral blade width of 11 mm to 20 mm is optimal to ensure high bearing capacity of the screw foundation, which is due to the fact that when immersed in the ground of the tip, the inter-turn gaps of the soil are not loosened, but on the contrary, are compacted by a spiral of a screw pile, increasing the reliability of the foundation, especially for complex soils.

The small area of contact with the soil (the thickness of the tip cone end is from 31 mm to 65 mm) and the presence of a spiral with the proposed geometric dimensions do not create critical pressure even on soft peat and sandy soils and do not allow the foundation to move even with deep freezing of the soil and at the same time reduce the complexity its immersion in the ground. Installation time takes only a few minutes.

The inventive screw pile is installed strictly vertically using special improvised means or machines. Installation time takes only a few minutes. Moreover, the contact area of the proposed screw pile foundation with the soil is insignificant compared to conventional foundations, due to this, such a foundation is much less susceptible to various kinds of movements, seasonal variations in the soil and distortions.

The foundation on the basis of such screw piles does not create critical pressure on soft and unstable soils, therefore, it can be installed without preliminary exploration. The use of this foundation is possible not only on complex soils, but also in earthquake-prone areas where ordinary concrete foundations can be damaged or destroyed, in addition, it is environmentally friendly and economical.

Annex 1

to the description of the utility model "Screw pile".

The results of research tests of screw piles for pulling in natural (field) conditions

Tests of screw piles in natural (field) conditions were carried out in the city of Barnaul at four experimental sites with soil bases, composed of sandy loam, sand and loam, i.e. most typical for southwestern Siberia. 37 tests were conducted. Control tests of piles during construction with static pressing, pulling and horizontal loads are regulated by GOST 5686-94 “Soils. Field test methods for piles. " For testing, piles of two sizes were selected: 2000 mm long, 76 mm in diameter (FM24 76 * 2000) and 2000 mm long, with a variable diameter of 76-114 mm (FM24 114 * 2000). An installation for testing piles in natural (field) conditions of UU-VSK, designed for loads up to 300 kN, was used as a test bench.

At each experimental site, three experimental piles of each size for static pressing loads and two experimental piles for static pulling loads were tested — a total of 21 tests.

When testing in solid sandy loam (site No. 1): up to a load (0.6-0.8) Fu, strains increase linearly with a small total pile upset; after which a pronounced shear zone is formed with a significant increase in the total draft (up to 15 mm); when Fu is exceeded, a continuous increase in pile upset occurs.

When testing in sands, fine medium density (site No. 2): deformations increase linearly to a load (0.4-0.5) Fu, the sediment during WF operation in the shear zone is decaying even with a total settlement of more than 20 mm.

When testing in hard loams (site No. 3): up to a load (0.6-0.7) Fu, the strains increase linearly with a small total pile settlement; then there is a sharp increase in precipitation, while the increase in precipitation is also almost linear (up to 10 mm); when Fu is exceeded, a continuous increase in the WF precipitation occurs. When tested by pulling loads, an increase in the output of WF from the soil is linear for most of the types of soils studied for the most part.

The total output of the pile from the soil until the beginning of undamped deformations does not exceed 4 mm.

Tests at sites No. 1 and No. 2 showed the same operation of the WF of both sizes for pulling loads. At site No. 3, the value of the ultimate resistance of the WF turned out to be different.

Based on the foregoing, at site No. 3, it was decided to conduct additional tests of the WF for pulling loads already tested for pressing loads, after their "rest". The time of "rest" of the pile before the test with pulling loads was 12-14 days, when regulated by GOST 5686-94 "Soils. Field Test Methods by Piles ”for six days.

Results of summer static soil tests using the BAU Screw Foundations.

The results of static soil tests using the BAU Screw Foundations are shown in Table 2.

The plots of the draft / output of the BAU Screw Foundations versus the vertical load are shown in FIG. 1 and 2. In FIG. 1 shows graphs of the dependence “load-sediment piles” S = f (P) at sites respectively No. 1, 2, 3. In FIG. Figure 2 shows the graphs of the dependence "load-output piles" DV = f (PV) at sites No. 1, 2, 3, respectively.

Experimental studies were conducted to determine the effect of frost heaving forces on the operation of the BAU Screw Foundations. In accordance with the work program, on the fourth experimental site located in the suburbs of Barnaul, 16 piles were tested on a pilot site flooded with flood waters with a WF soil base made of loamy loam, plastic, highly fouled, with a standard freezing depth of 2.3 m.

The normative and calculated characteristics of the soils of the experimental site No. 4 are shown in table 3.

Piles were left in the ground without load, and throughout the entire observation period, readings of the deformations of piles from the effects of frost heaving were taken. Graphic processing of data on elevation and deformation of the BAU Screw Foundations and soil is shown in FIG. 3.

Results and conclusions:

During the experimental observations of the deformations of piles I, II, III and 1-13 from the action of the forces of frost heaving of the soil was practically not observed. The difference between the initial measurements (at minimum negative temperatures) and subsequent strain measurements (at maximum negative temperatures) is within the measurement error.

Appendix 2

to the description of the utility model "Screw pile".

The results of research tests of screw piles for horizontal loads in natural (field) conditions

Tests of piles for horizontal loads are carried out in accordance with GOST 5686-94 in order to determine the amount of movement of piles under the influence of horizontal loads.

The magnitude of the load stage is usually taken as a multiple of the calculated design resistance of the pile to bending and should be no more than 1 / 10-1 / 15 of the estimated normative horizontal load on the pile.

At each stage of loading of a full-scale pile, counts are taken for all instruments for measuring deformations in the following sequence: zero count - before loading the pile, the first count - immediately after application of the load, then four counts sequentially with an interval of 30 min and then every hour until the conditional deformation (attenuation of displacement).

When testing soils with a reference pile or pile probe, readings at each loading stage are taken in the following sequence: the first readout immediately after applying the load, then two readings with an interval of 15 minutes and then with an interval of 30 minutes to conditionally stabilize the deformation.

The horizontal movement of the pile head at a given load level is considered stabilized if its increment is not more than 0.01 mm when the pile is located (to the depth of its incorporation) in the sands - in the last hour, in clay soils - in the last 2 hours. Forced testing of piles is permitted in those cases when the horizontal loads provided for by the project are short-term (installation).

Horizontal load tests of piles are recommended in the following ways:

1 - after stabilization of movements at each stage of the load, they go directly to the next stage. At the end of loading, a complete unloading is performed;

2 - after stabilization of movements at each load stage, it performs partial unloading by one stage to the previous stage, setting the value of residual and elastic deformation, the load is increased by two stages at once, i.e. to the size of the next step.

At the end of loading, complete unloading is performed in steps equal to one or two load steps.

In accordance with GOST 5686-94, the load of piles during their testing should be brought to a value that causes a movement of not less than 40 mm - for hollow round piles, pile piles and rammed with a widened heel.

During the control tests of working piles, tested up to the displacement specified in the design, but not more than 10 mm, the load capacity is taken to be the load corresponding to the given displacement on the graph, in the absence of restriction - the displacement equal to 10 mm

Field Experiment Results

A field experiment was conducted on the site located in the city of Barnaul, Zmeinogorsk tract 110 territory of the oncology center "Hope".

Geological structure of the site to a depth of 5 m:

1. The soil layer with a thickness of 0.4-0.6 m

2. Sand of medium size, physico-mechanical properties of which are shown in table 1.

Three groups of screw piles participated in the experiment: BAU FM24 76 × 2000, BAU FM24 76 × 2500, BAU FM24 76 × 3000, diameter 76 mm, length 2.0 m, 2.5 m and 3.0 m, respectively, 8 samples each.

General geometric characteristics of piles:

- outer diameter F76.1 mm;

- inner diameter F68.6 mm;

- thread diameter M24;

- flange thickness 8 mm.

According to the experimental procedure, samples of piles of the same type were tested in pairs.

Thus, 4 experiments were carried out for each type of pile.

Table 2 presents the bearing capacity of a screw pile 2.0 m. To the effect of horizontal load.

As a result of the field experiment, we obtained graphs of the dependence of the movement of the pile heads on the applied load.

In FIG. 4, 5, 6, 7 are graphs of the dependence of the deformation of piles No. 1, 2, 3, 4 with a length of 2 m from the action of horizontal load.

Table 3 presents the bearing capacity of a screw pile 2.5 m. To the effect of horizontal load.

In FIG. 8, 9, 10, 11 are graphs of the dependence of the deformation of piles No. 1, 2, 3, 4 with a length of 2.5 m from the action of the horizontal load.

Table 4 presents the bearing capacity of a screw pile 3.0 m. On the effect of horizontal load.

In FIG. 12, 13, 14, 15 are graphs of the dependence of the deformation of piles No. 1, 2, 3, 4 with a length of 3 m from the action of the horizontal load.

Table 5 shows the average values of the bearing capacities of screw piles for horizontal loads.

Table 6 shows the values of horizontal and vertical loads on multiblade screw piles "BAU"

findings

1. Analyzing the graphs of the dependence of pile deformations on the effect of horizontal load, we can conclude that the nature of the work of piles of all tested lengths in the soil is similar and at the moment of loss of stability is almost the same.

2. At intermediate points of displacement, a pile of 2.0 m in length has slightly higher load-bearing capacity due to greater rigidity.

3. In general, all piles operate according to the long flexible and short flexible rod scheme. In this regard, only the upper part of the pile, which is the same for all samples of tested piles, takes part in the work on the perception of horizontal load.

4. Screw blades do not participate in the work of piles, as they are in the lower section of piles.

5. Based on the field tests and their analysis, we can conclude that the bearing capacity of screw piles on the action of horizontal forces and moments for a length of 2 to 3 meters and a diameter of 76 mm does not depend on their length.

6. To increase the bearing capacity of piles, it is necessary to use piles of a larger diameter. It is also recommended to place screw blades in the upper section of the pile to enable them to work on the perception of horizontal loads.

Claims (5)

1. A screw pile, including a cylindrical shaft, a tip with a spiral, characterized in that the cylindrical shaft of the pile is made with a length of 3001 mm to 4000 mm, the cylindrical shaft of the pile is made stepped, consisting of at least two sections made with decreasing to the tip with diameters from 325 mm to 141 mm, the tip with a spiral is made from 1001 mm to 1500 mm long, the spiral is made with a spiral pitch of 41 mm to 50 mm and the width of the spiral blade is from 11 mm to 20 mm, the thickness of the tip cone end is from 31 mm to 65 mm. 2. A screw pile according to claim 1, characterized in that at least two parts of the cylindrical barrel are provided with a spiral. 3. A screw pile according to claim 1, characterized in that it is provided with a flange with a thickness of 11 mm to 20 mm with holes with a diameter of 16 mm to 50 mm. 4. A screw pile according to claim 1, characterized in that the flange is made in the form of a ring with round or oval holes. 5. A screw pile according to claim 1, characterized in that the flange is made in the form of a disk with diametrically located holes and a central hole.

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