Method of drilled pile manufacturing

FIELD: construction.

SUBSTANCE: method of drilled pile manufacturing includes well arrangement in soil. Supply of material into it. Compaction of soil under lower end of formed pile. In process of soil compaction, in the base of formed drilled pile with parametres equivalent to driven pile, its conventional camouflet cavity is arranged with diametre Dkp equal to diametre of dzs equivalent to driven pile, where: dzs - diametre (m) of equivalent driven pile. DkP - diametre (m) of conventional camouflet cavity produced in soil as it is displaced under lower end of formed drilled pile, by means of supply of controlled material volume to fill conventional camouflet cavity according to the following dependence : where V is controlled volume (m3) of material spent for filling of conventional camouflet cavity produced in soil due to its displacement into pile foundation. As well is filled with material in the form of hardening mix, preferably plastic concrete mix, diametre of equivalent driven pile is identified according to dependence , where dzs - diametre (m) of equivalent driven pile. Dskw - diametre (m) of well; Δh - measured value of subsidence (m) of plastic concrete mix in well as conventional camouflet cavity produced due to displacement of soil under lower end of formed pile is being filled. And in order to produce drilled pile with parametres of driven one of the same diametre, soil is treated in the lower end of pile till material subsides, preferably concrete mix, in well by value, which is compared with the one defined from the following ratio: Δh/Dskw=0.4. Besides in the lower end of well soil is exposed to forces, and their sufficiency is controlled (assessed) by flow of material additionally supplied to well in process of soil treatment, and its volume is identified according to formula , where Dskw - diametre (m) of formed pile. Besides in well reinforced with casing pipe, dynamic actions at soil are carried out until material subsidence value in casing pipe makes at least the following: , where Δhtr is subsidence (m) of material in casing pipe. Dskw - diametre (m) of well. Dfr - inner diametre (m) of casing pipe. Dynamic actions at soil in lower end of formed pile are carried out to achieve conventional failure, which is represented by material subsidence of not more than 2 mm in process of the last action, and when soils are compacted by electric explosions in pile foundation with application of electrode system, dynamic treatment is interrupted provided that electrode system freely installed on bottomhole in process of electric explosion sinks by not more than 1-2 cm, and in process of soil dynamic treatment at least one additional camouflet expansion is created along pile length, preferably, in zones of well opening of soils that are most pliant to compaction, which is detected by reaction of soil to test dynamic actions performed along pile length.

EFFECT: development of drilled piles with bearing capacity by soil, same as for driven piles, with minimum possible usage of resources and maximum possible usage of properties inherent in massif of soil that contains pile.

7 cl

 

The invention relates to the field of construction, namely the manufacture of bored piles.

It is known that the specific load-bearing capacity of driven piles, cast to a unit volume of the pile, significantly (several times) higher than that of bored piles. The bearing capacity of driven piles and drilling piles on the ground is calculated as the sum of the carrying capacity of the soil below the bottom end of the pile and on its lateral surface by friction of the pile in the soil. The calculated resistance of the soil on the side surface of the drilling piles SNiP 2.02.03-85 (clause 4.6) recommends that in table 2, compiled for driven piles. This difference in bearing capacity of the soil on the side of the knock-in and drilling of piles is taken into account by setting the corresponding coefficients of the conditions of the soil on the side of the pile, depending on how the device works. The values of these coefficients differ by several tens of percent and cannot account for the multiple differences in specific load-carrying capacity of drilling and driven piles. A significant proportion of the carrying capacity of driven piles is provided by the resistance of the soil beneath its lower end, thickened when submerged piles, and relevant to this seal, the modified stress-strain state of soil at the base of the driven piles.

SNiP 2.02.03-85 (item 2.4, a or b) set the s classification of driven piles. According to this classification to driven piles are as follows:

drilled piles, arranged by immersing inventory of pipe, the lower end of which is closed reserve in the soil Shoe or concrete tube, with subsequent extraction of these pipes as filling the wells with concrete;

- printed vibratorroundo piles arranged in a punched wells by filling wells hard concrete mixture, sealing vibrostanok in the form of a pipe with a pointed lower end and fixed thereto vibro.

The calculated resistance of the soil below the bottom end of such piles is taken from table 1 SNiP 2.02.03-85, i.e. for driven piles.

In the manufacture of bored piles in dry soils SNiP 3.02.01-87 (p) requires, after the sinking of wells, the soil in the bottom of the drill hole to be sealed to failure by dropping it tamping mass not less than 3-5 tons to achieve total faults for not less than the diameter of the piles. However SNiP 2.02.03-85, entered into force with 1.01.87 as JV 50-102-2003, published 18 years later, in the calculations of the bearing capacity of ramming and drilling of piles does not take into account the effect of soil compaction under the lower end of the drill piles.

Some exception SNiP 2.02.03-85 provides piles with camouflage by the broadening due to the introduction in the calculations of the bearing capacity for the soil factor s is Vij of the soil under the lower end of such piles γ Rrecommending to take γR=1,3. For all printed and drilling of piles, including piles with camouflage by the broadening of the calculated ground resistance R under the lower end of the pile, according to the requirements of SNiP 2.02.03-85 should be taken in accordance with paragraph 4.7. This item refers to table 7 [SNiP 2.02.03-85] when calculating the piles, the lower end of which is located in clay soils. The calculated resistance R for Sands should be calculated by the formulas given in paragraph 4.7 [SNiP 2.02.03-85]. The calculated resistance R Sands beneath the lower ends of bored piles, calculated under paragraph 4.7, often exceeded the value of the calculated resistance of Sands under the lower ends of the driven piles are shown in table 1 [SNiP 2.02.03-85]what can not be in principle. In 2003, this bug was fixed in SP 50-102-2003, where note to paragraph 7.2.7 was supplemented by a paragraph that sets the upper limit on R for drilling of piles, which may not exceed the values of R, for driven piles in table 7.1 SP 50-102-2003 for similar accommodation piles.

The calculated resistance of the soil beneath the lower ends of driven piles SNiP 2.02.03-85 requires to take in table 1, SP 50-102-2003 - in table 7.1, are absolutely identical table 1 SNiP 2.02.03-85.

Comparable installed SNiP 2.02.03-85 and is required for unconditional acceptance in the practice of design values calculated resistivity is of tyuleniy R under the lower ends of driven piles and bored piles applying (table 1 and table 7 SNiP 2.02.03-85), below for convenience and clarity of comparison in the following United table 1:

Notes:

1. For driven piles, the values of R written in normal font (14200).

2. For drilling piles values of R recordeditalics(3300).

When the depth of the piles, for example, length 15 m, clayey soils with a turnover of IL=0.1, the calculated resistance under the lower end of driven piles (7500 kPa) 4.5 times the estimated resistance under the lower end of the drill piles(1650 kPa).

At a depth of 10 m, the calculated values in the same soils differ in 6 times. In fine Sands at a depth of 15 m, the difference is 2.6 times, and at a depth of 10 m - 3.25 times. As you can see, the calculated resistance of the soil beneath the lower ends of driven piles at times exceed the estimated resistance under drilling piles equal to the depth in the same soil.

The present invention aims to eliminate contradictions, legalized in many regulations. The obviousness of the claimed technical solution is that which existed decades of conflict have not noticed any designers or inventors or scientists-geotechnical.

Natural stress-strain state (SSS) of the soil when immersed driven piles under its lower end changes in the soil which is to be the new VAT, determining, in the end, the increased resistance of the soil below the bottom end of the pile. Creating under the lower end of the drill piles VAT soil, similar to VAT soil under the lower end of driven piles, it is possible to provide the bearing capacity of soil beneath the lower end of the drilling piles, comparable with the bearing capacity of soil under the bottom end knock, and preliminary calculations of the bearing capacity of such drilling piles to use the values of R, set for driven piles. While the present invention sets a criterion to compare the equivalence of (specified values) VAT soil under the lower end of the drill piles after dynamic sealing impacts on the ground with a VAT of soil below the bottom end of the driven piles.

The known method of producing piles, including education in the soil pioneer wells, which is the area of formation of piles, which serves hardening material, and feeding hardening of the material in it excite high-voltage electrical discharges. Moreover, the feeding zone of the hardening material and excitation of digits to be moved along the depth of the zone of formation of the pile shaft. Allocated to high-voltage electric discharge energy increases the diameter of the corresponding zone of the well to a given diameter piles at this depth (WO No. 91/00941, SDA is published 1991). In the manufacture of piles according to the method of hardening the material is fed to the forming piles of implementation in the area of high-voltage electrical discharges. The flow of material and excitation of digits to be moved along the depth of the zone of formation of piles.

In this way it is possible to make drilling pile high load bearing capacity, comparable with the carrying capacity of driven piles.

However, in the known invention is not resolved the question of control over the creation and achievement under the lower end of a pile of stress-strain state of soil, equivalent stress-strain state of soil below the bottom end of the driven piles. In this case, the values of the calculated resistance of the soil R under the lower end of driven piles for calculating the carrying capacity of the drilling piles manufactured by a known method, can lead to disaster consequences.

A known method of manufacturing a drilling piles with camouflage widening, including education in the soil well, placing on the bottom of the hole charge explosives (he), filling wells hardening material and the initiation of charge [SNiP 3.02.01-87 (p); Manual on the construction of bases and foundations (to SNiP 3.02.01-83)/nyiop them. Nemertinea. - M.: stroiizdat, 1986. - 567 S.; Technical PRA the sludge of blasting in the energy construction. - M.: Energy, 1972, s].

Classification SNiP 2.02.03-85 describes the type of piles (p.2.5. g) related to piles, the estimated resistance of the soil below the bottom end of which SNiP 2.02.03-85 (clause 4.6) requires to adopt, in accordance with the provisions of paragraph 4.7 or table 7, i.e. as for drilling of piles.

Despite additional, very difficult and unsafe operations CENTURIES, in the calculations of the bearing capacity of the pile in the soil, the effect is reduced only to take into account the following factors: increase in the area of the piles, in the area of camouflage broadening, and the introduction of the factor values of the operating conditions of the soil under the lower end of a conventional drill piles, increased by 30% (according to SNiP 2.02.03-85, paragraph 4.6, γc=1,3). Very careful consideration in the calculation of the bearing capacity of the ground camouflage piles actually achieved from the explosion of the explosive effect, due to the fact that this technical solution is not resolved the issue management creating and controlling the achievement of the stress-strain state of soil below the bottom end of the camouflet piles, the equivalent stress-strain state of soil below the bottom end of the driven piles.

A known method of manufacturing bored piles, received in Russia called "pile-ostrich", and in European countries similar piles called "pile-Franks". This method includes:

- education in soil wells;/p>

- fastening of the wall of the well casing pipe;

- portions flow into the well casing material (concrete mixture);

- knocking out concrete mixture from the casing Baba discharged inside the pipe;

- utrambovyvaya in ground concrete mixture, with formation of a broadening of the pile shaft;

- reinforcement of the pile shaft above ening;

- concreting of this part of the pile shaft [Klein G.K., Smirenkin P.P. "Bases and foundations", M.: Higher school, 1961, s (see str)].

In this way we obtain a pile with a high load capacity on the ground, close to the carrying capacity for driven piles.

However, the issue of control over the change of the stress-strain state of the soil and not the degree of his seal, which guarantees the stress-strain state of soil, equivalent stress-strain state of soil below the bottom end of the driven piles.

A known method of manufacturing a drilling piles in Newtonian soils, according to which after drilling a well loosened by the drilling tool, the soil in the bottom of a well compacted by dropping into the well tamping weight 3-5 tons. Plugging of the soil in the bottom of a well produced until the value of no greater than 2 cm over the last 5 strokes, the total amount of failures tamping should sostavlenie less than the diameter of the hole (SNiP 3.02.01-87, paragraph 11.20).

In this way you can receive drilling piles with high load capacity on the ground.

However, in this method also does not resolve the issues of management and control of the collateral under the lower end of manufactured drilling piles of stress-strain state of soil, equivalent stress-strain state of soil below the bottom end of the driven piles. Therefore, the very high complexity of the compaction of soil in the bottom hole (to achieve a total failure not less than the diameter of the hole) and an unreasonably large number of cycles stamp regardless of soil conditions is actually not taken into account in the calculation of the bearing capacity of the drilling piles. Due to the lack of solutions, permitting to establish modified stress-strain state of soil in the drop tamping, the carrying capacity of the drilling piles even after sealing the bottom of the borehole as described in the SNiP 3.02.01-87 (p) method expects as usual drilling pile. In other words, this method of making piles has the disadvantages for other drilling of piles.

The technical task of the present invention is to provide drilling (drilling) of piles bearing capacity of the ground, as driven piles, at the lowest possible use of resources and maximize the prob is the author using the array properties of the soil, capacity of the pile.

To solve this problem in the method of manufacturing bored piles, including education in the soil wells, supply of material, soil compaction under the lower end of the formed piles, compaction of the soil at the base generated bored piles to the parameters of the equivalent parameters of driven piles, conventional camouflage cavity comply with a diameter of Dkpequal to the diameter dzsequivalent to driven piles, where:

dzs- diameter (m) is equivalent to driven piles;

Dkp- diameter (m) conditional camouflage cavity formed in the soil during its displacement under the lower end formed by drilling piles, by filing for filling conventional camouflage cavity of a controlled volume of material following dependencies:

,

where V is controlled volume (m3material used for filling conventional camouflage cavity formed in the ground due to its displacement in the Foundation piles. When filling the well material in the form of hardening of the mixture, preferably plastic concrete mixture, the equivalent diameter driven piles is determined by dependencies

,

where dzs- diameter (m) is equivalent to driven piles;

Dskw- diameter (m) of the borehole;

Δh is the measured value, precipitation(m) plastic concrete mix in the hole when filling conditional camouflage cavity, obtained due to displacement of soil beneath the lower end of the forming piles. And for the drilling of piles with knock-in options of the same diameter affect the soil in the lower end of the pile to the precipitation material, preferably concrete mix in the hole on the value, which is compared with a certain ratio

In addition, at the lower end of the well carry out impact on the ground, and the adequacy of control (evaluate) flow additionally submitted into the well in the process impacts on the soil material, the amount of which is determined by the formula

,

where Dskw- diameter (m) formed piles.

In addition, in the borehole, fixed casing pipe, dynamic impact on the ground make before reaching the settling of the material in the casing pipe, not less than

,

where Δhtr- draught (m) of the material in the casing pipe;

Dskw- diameter (m) of the borehole;

Dtr- inner diameter (m) casing pipe.

The dynamic effects on the soil at the lower end of the formed piles carry out to achieve conditional refusal to take a draught of material is not more than 2 mm over the last impact, while soil compaction electric explosions at the base of the pile using the a W of the electrode system, dynamic effects cease, provided that the electrode system, freely mounted on the bottom with an electrical explosion, falls no more than 1-2 cm And during dynamic impact on the ground create at least one additional camouflage broadening along the length of the pile, preferably in the areas of intrusion borehole soil, the most easy to seal, installing on ground reaction test dynamic action carried out by the length of the piles.

The achievement of the technical result is confirmed by the following reasoning. It is known that immersion driven piles or piles device according to the technology described in SNiP 2.02.03-85 (item 2.4 a, b) [beholden BV "Experimental and theoretical studies of the process of interaction of the soil with driven piles and creation on their basis of practical methods of calculation of piles", abstract of thesis for obtaining the title of doctor of technical Sciences, - M, VNIIKP, 1987, p.472; Malyshev, M.V., Boldyrev, "soil Mechanics. Bases and foundations", M: "DIA", 2001, s; instruction on the design and installation of pile foundations of buildings and structures in Moscow. - M.: state unitary enterprise "NIAC", 2001, s] under its lower end to a depth of 1,5dzs(dzs- diameter (m) driven piles) is soil compaction with subsequent displacement in his hand, through which it around the piles formed a zone of compacted soil with a diameter of D zu

From theory of camouflage explosions known that around camouflage cavity formed area of the compacted soil, the diameter Dzuwhich reaches

where Dkp- diameter (m) camouflage cavity [Smirnov V.I., Golitsyn D.M., Melnikov L.L. "Construction of underground structures using camouflage explosions", M.: Nedra. 1981, s]. Camouflage believe the cavity, obtained by an underground explosion without the formation of craters on the earth's surface. Experimental studies proved that the set ratio is almost independent of the scale and depth of the explosion, and depends only on the characteristics of the soil.

When immersed driven piles is internal vapor soil in the level of its lower end, on the depth of immersion. Internal vapor soil can be roughly thought of as the formation of "camouflage cavity", that simultaneously with its formation is filled with a body (material) submerged piles. Moreover, the diameter of this "camouflage cavity" always corresponds to the diameter submersible pile dzs(m).

The compaction of soil in the bottom hole is necessary in the soil surrounding the lower end formed by drilling piles, to create a zone of deformation of soil, equivalent to the area of ground deformation at the base of the driven piles and the area, which which have changed the voltage in the ground, equivalent to the area of the changed voltage at the base of the driven piles. In this case, the ground under the lower end of the drill piles will provide a carrying capacity equal to the bearing capacity of the soil at the base of driven piles with the same diameter, at the same depth, i.e. can be equated formula (1) and (2)

and,

where it is easy to find the diameter of the camouflet cavity

or

For drilling piles with a diameter of Dskwequal to the diameter driven piles dzsyou can burn

Then camouflage the cavity of the minimum required diameter to ensure the establishment under the lower end of the bored piles VAT soil, equivalent to VAT soil under the lower end of driven piles should be determined by the formula

In this case, the carrying capacity of the drilling piles underneath its bottom end can be calculated (and therefore load) as a driven pile, immersed in the same soil at the same depth.

In the well, filled with plastic concrete mixture, it is possible to form a camouflage cavity in the drop tamping, the explosion of the explosive or series of electrotribal. Received during each stroke of the tamping or electrical explosion camouflage cavity immediately ispolnjaetsja plastic concrete mixture, therefore, the amount of camouflage cavity, the resulting series of dynamic effects, controlling for total sediment concrete mix in the hole. The diameter of the camouflet cavity is calculated by the well-known formulas recommended in [Manual work when the device of the bases and foundations (to SNiP 3.02.01-83)/nyiop them. Nemertinea. - M.: stroiizdat, 1986. - 567 S.]

or [Technical rules for blasting in the energy construction. - M.: Energy, 1972, - 208 S.]

where V is the volume (m3) concrete mix, housed in a camouflage cavity is determined by the size of its precipitation in the well multiplied by the cross sectional area of the bore in the measured cross section

where Dskw- diameter (m) borehole; Δh value (m), which settled the concrete mix in the hole when forming the camouflet cavity.

Can (6) and (7) to write in a generic form

After substituting (8) into (9) we get

We substitute (5) into (10) and after transformations will receive the value of Δh, which should settle the concrete mix in the hole and controlled during the formation of the camouflet cavity of the minimum required diameter to create under the lower end of the drill is ramming piles VAT soil, equivalent to VAT soil under the lower end of driven piles

Rounding in the safety margin, we get

To get bored piles high bearing capacity of the ground corresponding to the bearing capacity of driven pile with the same diameter, rather at the lower end of the pile to form a broadening when filling in which the concrete mix in the hole will settle on an amount equal to(m), the value of precipitation is controlled in the process impacts on the soil under the lower end of the drill piles. When the soil surrounding the lower end of the drill piles shall be established in the zone of compaction of soil, areas of altered stress and strain, equivalent areas of soil compaction, areas of altered stress and strain at the base of driven piles with a diameter of dzs(m), design load-carrying capacity of the drilling of the pile in the soil beneath its lower end can be calculated using the calculated resistance of the soil, determined according to table 1 SNiP 2.02.03-85, as for driven piles. Such drilling pile can be loaded as driven with the same diameter, immersed in the same soil at the same depth.

In loose Sands or other soft soils containing legkoobratimy zone, due to the sealing of the latter, camouflage cavity can be mean is the super large sizes. In this case, in the calculation of the bearing capacity of the drilling piles should be taken diameter mapped driven piles, which is calculated by the formula

where dzs- diameter (m) is equivalent to driven piles.

In other words, for the manufacture of piles by the present invention in the soil to perform well. Fill the borehole, at least in the area of energy conversion hardening material such as concrete or other material. And then compacted soil in the bottom of the borehole to the formation below the lower end of the drill piles of stress-strain state (SSS) of soil, equivalent stress-strain state of soil at the base is equivalent to driven piles. Achieving the required degree of compaction and the creation of zones in which the natural stresses in the deformation of the soil at the base of the drilling piles reached the stresses and strains corresponding to the stresses and deformations under the lower end of driven piles in areas equivalent to the area under the lower end of driven piles, control (evaluate) the sediment material (concrete mixture) in the well to a value of 0.4 of the diameter of the hole

where Dskw- diameter (m) wells in the level mirrors the concrete mixture in the wellbore, where the measured reduction and compare the diameter driven piles d zs(m).

When using a casing for mounting on the well walls is controlled subsidence of the concrete mix at the mouth of the casing, the amount of precipitation is determined by the formula

where Δhtr- draught (m) concrete mix at the mouth of the casing; Δhskw- imputation (m) precipitation concrete mixture in loose well; Dskw- diameter (m) wells; Dtr- inner diameter (m) casing pipe.

After substituting (12) into (14) we get

If you do not perform the recalculation, calculation of load-carrying capacity of the drilling piles in the lower end of which was compacted soil and casing pipe material level decreased by the amount Δhtrthat should take estimated resistance of the soil as under the lower end of driven piles, and the equivalent diameter driven piles is calculated by the formula

Monitoring can be done not only by upsetting the concrete mix in the hole, but also by the volume of material is additionally supplied into the well, the main thing is that this provides a line formed under the lower end of the bored piles VAT soil VAT soil at the base of the driven piles. Appreciate this under VAT by the amount of material (concrete mixture) in a dense body, utrambovannogo in the soil under the bottom to the CMA drilling piles, namely, by volume additionally submitted into the well in the process of compaction of soil at the base of the drilling piles, this volume should exceed the amount, which is calculated by the formula

,

where Dskw- diameter (m) generated piles, equivalent to knock.

Concrete mix, despite its mobility, good fixation of residual deformations of the soil is reached during each cycle of its seal.

For the manufacture of bored piles using electrical discharges used cast concrete mixtures, which are freely pumped through hoses and pipes, these compounds are liquid density of 1.73...2,35 t/m3. The mobility of the concrete mixtures with low water-cement ratio (0.3 to 0.5) is provided through the use of effective super - and hyperplasticity additives, for example: C-3; NN(FM) and other

Dynamic effects on the soil at the lower end of the formed piles can be made to achieve conditional refusal to take a draught of material is not more than 2 mm over the last impact.

Implementing dynamic impact on the ground, you can, in addition to the impacts on the level of the lower end of the drilling piles, to obtain at least one additional camouflage broadening along the length of the piles. The greatest effect is achieved if osushestvlyaetsya impact on the soil and provide additional camouflage for the broadening of the zones (the substratum), where the excavation of the borehole between the solid substrates were dissected thin inclusions (interlayer) weak soils, the most easy to seal, installing on ground reaction test dynamic action carried out on the well depth.

When soil compaction at the base of the piles by electrical explosions it is necessary to examine the degree of soil compaction, which is recognized as sufficient, if the electrode system, loosely mounted on the rock by electrical explosion, falls no more than 1-2 cm, scan “on the rebound”. After reaching a sufficient degree of compaction of the soil below the bottom end of the drill piles as a result of implementation of a series of electrotribal, which provides the minimum sludge piles, it is found experimentally that when an electrical discharge (the explosion) between the electrodes, mounted freely on the soil in the bottom of a well, there is a rebound, like the recoil of the weapon when fired. This effect is reliably detected by the operator at the well treatment.

The essence of the invention is expressed by the set of essential features, sufficient to achieve the claimed invention technical result, which is to control the guaranteed supply of bearing capacity under the lower end is m the drilling of the pile in the ground, which was achieved under the lower ends only of driven piles by applying managed, controlled deep soil compaction, which is formed pile.

Almost 30 years of experience designing and device for drilling piles showed that the bearing capacity of soil at the base of these piles were underutilized due to the lack of valid, reliable methods of controlling the degree of compaction of soil, comparable with the parameters of the seals under the lower end of driven piles. The inventive control method helped to make the process of soil compaction, managed, every time receiving a result corresponding to the bearing capacity of the ground knock the pile of the appropriate diameter.

Thus, for the first time had the opportunity in the manufacture of drilling piles safely control the provision of the bearing capacity of the ground under its lower end, is equivalent to the carrying capacity below the lower end of driven piles corresponding diameter. This is made possible by known techniques to perform preliminary calculations of the bearing capacity of bored piles, using the data of table 1 SNiP 2.02.03-85, as in the calculation of driven piles, with subsequent verification of the calculation results of the tests with a pressing load according to GOST 5686-94.

Introduction in the known method of manufacturing brown who's piles significant, not previously known method of making piles of trait - method of controlling dynamic impact and its results, which helped to create a new way of controlled influence on the soil under the lower end of the drill piles to create in the lower end of the formed drill piles of stress-strain state of soil and soil density corresponding to the density and stress-strain state of soil below the bottom end is equivalent to driven piles, the diameter of which is determined by the formula

where dzs- diameter (m) is equivalent to driven piles;

Dskw- diameter (m) of the borehole;

Δh value (m) precipitation of material in the borehole due to soil compaction in the lower end of the formed piles, which control the degree of approximation of the bearing capacity of the ground drilling piles to the relevant parameters driven piles.

Introduction in the known method of manufacture of drilling piles significant, previously unknown in the method of making piles characteristic, namely, constant control over the volume of the generated conditional camouflage cavity, which is filled automatically fed into the well material, and the volume of the material filling the cavity, determine at any point in time cross-section equivalent to driven piles, which, in itsturn, evaluate the bearing capacity of the soil. This data is used for rapid calculation of the bearing capacity under the lower end of the drilling piles, as under the lower end of driven piles equivalent section in the preliminary design calculations.

This has revealed a new and unexpected function, and less soil compaction in the local area, at the lower end formed by the drilling of piles, ensure its carrying capacity as driven piles. Controlling the change of the stress-strain state of soil, up to levels equivalent stress-strain state of soil beneath the lower end of driven piles, get sverhsummarny a positive effect. Without increasing costs (on the contrary, even at a lower cost) produce qualitatively new drilling pile, bearing capacity of soil under the lower end of which is several times higher than the carrying capacity below the lower end of a conventional drill piles and corresponds to the bearing capacity of soil beneath the lower end of driven piles, the diameter of which is determined by the formula

,

where dzs- diameter (m) is equivalent to conventional driven piles, which can be in dense soils is less than the cross-section of the drill piles and loose Sands may exceed the cross-section of the drill piles;

V - volume (m3material filling the camouflet cavity, define or upsetting him in the well, or by volume, measured when electric current is applied to the well to fill the camouflet cavity.

If you control the amount of material filled camouflage cavity, upsetting the concrete mix in the hole, the cross section is equivalent to driven piles is determined by the formula

,

where dzs- diameter (m) is equivalent to driven piles.

Such zones can be created in many places along the length (depth) of the pile shaft. The advantage should be given to areas where they were exposed weak, easily compactable soils, for example, to create a seal above the roof stronger ground. In this case, each shaped seal, taken on the roof stronger ground, will ensure a solid ground as under the lower end of driven piles at the depth of the soil with increased strength characteristics. Areas of weak soils is determined during the test seal the borehole. Thus, most fully use the capabilities of the Foundation soil.

Examples of practical implementation of the invention.

For example, when drilling piles with a diameter of 600 mm length 10 m borehole bottom at this depth (10 m) were dissected semi-loam with IL=0,1. When soil compaction at the base of this rig St. and, the result is a streamlined, according to the invention, control, it was recorded that under the lower end of the drill piles tramboline in the soil 0.02 m3filed additional material.

To account for the degree of compaction of the soil and formed a VAT of soil, equivalent to knock the pile, the diameter of which can be determined by the formula

.

We can say that the soil is submerged driven pile section 35×35 cm, the cross-sectional area of 0.12 m2. The calculated resistance of the soil below the bottom end of which is, according to table 1 SNiP 2.02.03-85, 7300 kPa (730 t/m2), and soil bearing capacity under the lower end of the drill piles that had tramboline in the soil 0.02 m3that is 0.12 m2×730 t/m2=87,6 so

For drilling piles with a diameter of 0.6 m, the area of 0.28 m2the estimated resistance of the soil below the bottom end is, according to table 7 SNiP 2.02.03-85, 1200 kPa (120 t/m2), and soil bearing capacity under the lower end of the drill piles is to 0.28 m2×120 t/m2=33,6 tamahagane control soil compaction under the lower end of the drill piles according to the claimed invention, without application of additional installed cost objective the carrying capacity of the drilling piles after compaction under its lower end, exceeding the 2.6 times defined by existing rules.

Another example: when drilling piles with a diameter of 400 mm length 10 m borehole bottom at this depth (10 m) were dissected makoplasty loam with IL=0,5. When soil compaction at the base of this drilling piles, due to the well organized, according to the invention, control, it was recorded that managed to trampovat in the soil below the bottom end of the pile 0.08 m3gravel lodged in the well.

The degree of compaction of the soil and formed a VAT of soil, equivalent to knock the pile, the diameter of which is determined by the formula

,

We can say that the soil is submerged driven pile section 50×50 cm, the calculated resistance of the soil below the bottom end of which is, according to table 1 SNiP 2.02.03-85, 1500 kPa (150 t/m2), and soil bearing capacity 0,50 x 0,50 m2× 150 t/m2=37,5 so

For drilling piles with a diameter of 0.4 m, an area of 0.125 m2the estimated resistance of the soil below the bottom end is, according to table 7 SNiP 2.02.03-85, 700 kPa (70 t/m2), and soil bearing capacity under the lower end of the drill piles of 0.125 m2×70 t/m2=8,7 so by controlling the compaction of soil under the lower end of the drill piles according to the claimed invention, without additional costs derived objectively set the current carrying capacity of the drilling of the pile in the soil beneath its lower end (37.5 tons), which exceeds a certain existing rules (8.7 t) 4.3 times.

1. A method of manufacturing bored piles, including education in the soil wells, supply of material, soil compaction under the lower end of the formed piles with the formation of the camouflet cavity, characterized in that the compaction of the soil at the base generated bored piles with parameters equivalent to driven piles, conventional camouflage cavity comply with a diameter of Dkpequal to the diameter dzsequivalent to driven piles, where
dzs- equivalent diameter driven piles;
Dkp- diameter camouflage cavity formed in the soil during its displacement under the lower end formed by drilling piles, by filing for filling conventional camouflage cavity of a controlled volume of material following dependencies:
,
where V is controlled amount of material used for filling conventional camouflage cavity formed in the ground due to its displacement in the base of the piles.

2. The method according to claim 1, characterized in that during the filling of the well material in the form of hardening of the mixture, preferably plastic concrete mixture, the equivalent diameter driven piles is determined by dependence
,
where dzsthe equivalent diameter is driven piles;
Dzs- the diameter of the borehole;
Δh is the measured value, precipitation plastic concrete mix in the hole when filling conditional camouflage cavity obtained by displacement of the soil under the lower end of the formed piles.

3. The method according to claim 2, characterized in that for obtaining drilling piles with parameters driven piles with the same diameter affect the soil in the lower end of the pile to the precipitation material, preferably concrete mix in the hole on the value, which is compared with a certain ratio

4. The method according to claim 1, characterized in that the lower end of the borehole perform dynamic pulse effects on the soil, and the adequacy of control (evaluate) flow additionally submitted into the well in the process impacts on the soil material, the amount of which is determined by the formula

where Dskwthe diameter of the formed piles.

5. The method according to claim 1, characterized in that hole fixed casing pipe, dynamic impact on the ground make before reaching the settling of the material in the casing pipe, not less,
than,
where Δhtr- sediment material in the casing pipe;
Dskw- the diameter of the borehole;
Dtr- inner diameter of the casing pipe.

6. The method according to claim 1 or 5, otlichuy is the, the dynamic effects on the soil at the lower end of the formed piles carry out to achieve conditional refusal to take a draught of material is not more than 2 mm over the last impact, while soil compaction electric explosions at the base of the pile using the electrode system dynamic effects cease, provided that the electrode system, freely mounted on the bottom, in the electric explosion of falls by no more than 1-2 cm

7. The method according to claim 1 or 5, characterized in that during a dynamic impact on the ground create at least one additional camouflage broadening along the length of the pile, preferably in the areas of intrusion borehole soil, the most easy to seal, installing on ground reaction test dynamic action carried out by the length of the piles.



 

Same patents:

Driven pile // 2386748

FIELD: construction.

SUBSTANCE: invention is related to construction, in particular to pile foundations. Driven pile consists of shaft with axial hole, sharpened tip with circular base and conusoidal shell with spike, cavities inside shell filled with hardening solution. There is a threaded hole in tip base, which is closed with threaded plug with stem. Tip shell is rumpled with submergence force after removal of threaded plug and additional submersion of pile. For additional increase of bearing capacity there is an elastic shell on lower part of shaft with facilities for fixation of its upper and lower ends; cavity between elastic shell and shaft surface; protective jacket with facilities of its fixation of shaft, which slides in radial direction and embraces elastic shell. There is a radial hole in shaft, which connects longitudinal hole with specified cavity transformed into support belt after the pile has been submerged at the specified depth, the cavity has been filled with hardening solution via holes in shaft and the solution has hardened.

EFFECT: improved bearing capacity of hollow piles.

4 cl, 7 dwg

FIELD: oil-and-gas.

SUBSTANCE: invention related to construction, particularly can be used for bored piles with enlarged base arrangement. The method includes hole boring, hole opening with mechanical clampshell enlarger, reinforced cage installation and filling in the hole with concrete mixture. Developing enlargement with ration of enlargement diametre to hole diametre, equal de/dh≥2 with rotation velocity equal n=20-100 revolution per minute, dependant on ground conditions. After covering distance 0.8 h, where h - height of enlargement, stop axial supply of boring media and at that level, during 3-5 revolutions execute enlargement base cleaning, and ground collector and voids between enlarger blades complete filling. Turn on axial supply and execute boring till enlargement total height and enlargement blades closure. Take away enlarger, then concrete enlarged base, install reinforced cage and complete bored piles arrangement with concreting its core.

EFFECT: method of bored pile arrangement efficiency increase and hole enlarger design improvement, hole enlarger reliability increase, easing of ground withdrawal out form ground collector and better quality of constructed bore pile.

4 cl, 3 dwg

FIELD: construction industry.

SUBSTANCE: invention refers to construction industry and namely to construction of bearing piles in ground rock. Device for making multi-layer sealed pile in ground rock includes, in the combination, elongated hollow tube having longitudinal axis, upper inlet end for material, open lower discharge end for material and diametre of the first external surface and common formed lower head element at open discharge end, which has diametre of the second external surface, which is more than diametre of the first external surface and made with the possibility of transmitting combination from axial and transverse stress components when hollow tube is lowered. Head element consists of common attachment to hollow tube; at that, head element includes lower driving end which in general has configuration of flattened cone between head element of external surface and lower discharge hole made in the lower driving end, and back end having in general the configuration of flattened cone, and cap of the head element covering lower discharge hole. Lower head element with the cap and hollow tube are formed for being introduced into ground rock and for displacing the earth when hollow tube with lower head element and the above cap is lowered into ground rock so that a cavity is formed in ground rock. The cap is at least partially removed from lower discharge hole when hollow tube is then lifted from the formed cavity in order to perform passage of material through lower discharge hole to the cavity section released with hollow tube and lower head element. The latter has the form of cross section and the sizes which are more than the shape of cross section and sizes of hollow tube in order to decrease friction forces on hollow tube when penetrating into ground rock and being removed from it.

EFFECT: improving reliability of the pile and capacity and production effectiveness of piles.

34 cl, 26 dwg

FIELD: construction.

SUBSTANCE: invention is related to methods for arrangement of pile foundations for structures, to pile foundations and shell structure for creation of widened foot for pile foundations. Method for creation of pile foundation for structures, according to which the following stages are executed on site to arrange the mentioned foundation - well for installation of foundation pipe is drilled with the help of the first auger drill. The following section is drilled under lower end of installed foundation pipe. Cavity is arranged in the specified section by means of scraper and pressure of water jet. Loose soil is removed from specified cavity by mentioned first drill. Pipe for set of tools and accessories with the second auger drill and flexible shell that envelopes the lower part of the second specified drill is lowered through foundation pipe into lower part of specified section. Excess pressure is built up in specified shell, and moulding material is injected into specified cavity, surplus of which is then removed by the second auger drill. After mentioned material hardens, the specified shell is blown off and removed via specified foundation pipe. Reinforcing device is lowered into foundation pipe. Concrete material is poured into foundation pipe, at that specified cavity is filled, and specified reinforcing device is embedded into concrete, thus creating widened foot for foundation pipe. Versions of method and pile foundation are also stated.

EFFECT: higher stability and resistance to compressing and stretching forces, lower material intensity.

5 cl, 26 dwg

FIELD: building.

SUBSTANCE: invention refers to building, in particular, to strengthening of the bases under the basements. The way of strengthening of the basement erected on waterlogged priming coats and near to the located constructions includes supply of early strength concrete in the metal tubing established in driven wells, drilled through a basic part of the basement and a ground. Pipes are made with the welded boots, in pipes lower explosive charges and fill with early strength concrete, then the explosive charges are detonated, remaining hollownesses of driven wells and pipes are filled with early strength concrete.

EFFECT: provision of reliable strengthening of the basements erected in waterlogged priming coats and near to located constructions; increase of load-carrying capacity.

2 dwg

FIELD: construction, particularly bored piles with enlarged footing or enlargements at the bottom of the pile.

SUBSTANCE: method involves drilling well; filling the well with concrete mix and non-detonating composition including fuel and oxidizer; igniting non-detonating composition by applying low-voltage pulse to electric igniter and combusting non-detonating composition in deflagration regime to create camouflet void with following concrete mix hardening. The fuel is solid hydrocarbon selected from polyethylene, polypropylene and polystyrene. The oxidizer is sodium or potassium chlorate. Non-detonating composition is supplied in well before well filling with concrete mix.

EFFECT: decreased pile production time due to accelerated concrete mix hardening and improved produced pile quality.

6 cl

FIELD: bulkheads, piles, or other structural elements specially adapted to foundation engineering, particularly concrete or concrete-like piles cast in position with enlarged footing or enlargements at the bottom of the pile.

SUBSTANCE: reinforcement device is used to erect pile foundation with the use of foundation pile having at least one longitudinal cavity. Reinforcing device comprises a number of joined reinforcement members hingedly connected with central annular member located so that reinforcement device may be collapsed during installation and erected during device usage. Reinforcement device is connected to pile by at least one member working in tension. Foundation pile reinforced with the use of said device and method for foundation pile driving and pile bottom reinforcement are also disclosed.

EFFECT: increased uniformity of reinforcement distribution over pile bottom, improved compression and stretching force damping, decreased labor inputs and material consumption.

36 cl, 25 dwg

Bearing pile // 2251609

FIELD: building, particularly for constructing foundations of various building structures.

SUBSTANCE: bearing pile comprises head, rod and tip fixed to embedded rod part by embedded member. The tip is formed of thermoplastic concrete and has electric heater located inside the tip. Electric heater heats the tip after driving thereof into ground as far as it will go to obtain softening temperature of 80-150°C. Then the pile is fully driven in ground. Electric heater wires are placed in tube in longitudinal rod direction and brought outside under pile head for connection thereof with electric power source.

EFFECT: increased load-bearing pile capacity due to provision of widened pile tip support area.

2 cl, 5 dwg

The invention relates to the construction of pile foundations of bored piles in silty-clay soils
The invention relates to the field of construction and can be used when creating the broadening of piles, mainly constructed in soft ground

Bearing pile // 2251609

FIELD: building, particularly for constructing foundations of various building structures.

SUBSTANCE: bearing pile comprises head, rod and tip fixed to embedded rod part by embedded member. The tip is formed of thermoplastic concrete and has electric heater located inside the tip. Electric heater heats the tip after driving thereof into ground as far as it will go to obtain softening temperature of 80-150°C. Then the pile is fully driven in ground. Electric heater wires are placed in tube in longitudinal rod direction and brought outside under pile head for connection thereof with electric power source.

EFFECT: increased load-bearing pile capacity due to provision of widened pile tip support area.

2 cl, 5 dwg

FIELD: bulkheads, piles, or other structural elements specially adapted to foundation engineering, particularly concrete or concrete-like piles cast in position with enlarged footing or enlargements at the bottom of the pile.

SUBSTANCE: reinforcement device is used to erect pile foundation with the use of foundation pile having at least one longitudinal cavity. Reinforcing device comprises a number of joined reinforcement members hingedly connected with central annular member located so that reinforcement device may be collapsed during installation and erected during device usage. Reinforcement device is connected to pile by at least one member working in tension. Foundation pile reinforced with the use of said device and method for foundation pile driving and pile bottom reinforcement are also disclosed.

EFFECT: increased uniformity of reinforcement distribution over pile bottom, improved compression and stretching force damping, decreased labor inputs and material consumption.

36 cl, 25 dwg

FIELD: construction, particularly bored piles with enlarged footing or enlargements at the bottom of the pile.

SUBSTANCE: method involves drilling well; filling the well with concrete mix and non-detonating composition including fuel and oxidizer; igniting non-detonating composition by applying low-voltage pulse to electric igniter and combusting non-detonating composition in deflagration regime to create camouflet void with following concrete mix hardening. The fuel is solid hydrocarbon selected from polyethylene, polypropylene and polystyrene. The oxidizer is sodium or potassium chlorate. Non-detonating composition is supplied in well before well filling with concrete mix.

EFFECT: decreased pile production time due to accelerated concrete mix hardening and improved produced pile quality.

6 cl

FIELD: building.

SUBSTANCE: invention refers to building, in particular, to strengthening of the bases under the basements. The way of strengthening of the basement erected on waterlogged priming coats and near to the located constructions includes supply of early strength concrete in the metal tubing established in driven wells, drilled through a basic part of the basement and a ground. Pipes are made with the welded boots, in pipes lower explosive charges and fill with early strength concrete, then the explosive charges are detonated, remaining hollownesses of driven wells and pipes are filled with early strength concrete.

EFFECT: provision of reliable strengthening of the basements erected in waterlogged priming coats and near to located constructions; increase of load-carrying capacity.

2 dwg

FIELD: construction.

SUBSTANCE: invention is related to methods for arrangement of pile foundations for structures, to pile foundations and shell structure for creation of widened foot for pile foundations. Method for creation of pile foundation for structures, according to which the following stages are executed on site to arrange the mentioned foundation - well for installation of foundation pipe is drilled with the help of the first auger drill. The following section is drilled under lower end of installed foundation pipe. Cavity is arranged in the specified section by means of scraper and pressure of water jet. Loose soil is removed from specified cavity by mentioned first drill. Pipe for set of tools and accessories with the second auger drill and flexible shell that envelopes the lower part of the second specified drill is lowered through foundation pipe into lower part of specified section. Excess pressure is built up in specified shell, and moulding material is injected into specified cavity, surplus of which is then removed by the second auger drill. After mentioned material hardens, the specified shell is blown off and removed via specified foundation pipe. Reinforcing device is lowered into foundation pipe. Concrete material is poured into foundation pipe, at that specified cavity is filled, and specified reinforcing device is embedded into concrete, thus creating widened foot for foundation pipe. Versions of method and pile foundation are also stated.

EFFECT: higher stability and resistance to compressing and stretching forces, lower material intensity.

5 cl, 26 dwg

FIELD: construction industry.

SUBSTANCE: invention refers to construction industry and namely to construction of bearing piles in ground rock. Device for making multi-layer sealed pile in ground rock includes, in the combination, elongated hollow tube having longitudinal axis, upper inlet end for material, open lower discharge end for material and diametre of the first external surface and common formed lower head element at open discharge end, which has diametre of the second external surface, which is more than diametre of the first external surface and made with the possibility of transmitting combination from axial and transverse stress components when hollow tube is lowered. Head element consists of common attachment to hollow tube; at that, head element includes lower driving end which in general has configuration of flattened cone between head element of external surface and lower discharge hole made in the lower driving end, and back end having in general the configuration of flattened cone, and cap of the head element covering lower discharge hole. Lower head element with the cap and hollow tube are formed for being introduced into ground rock and for displacing the earth when hollow tube with lower head element and the above cap is lowered into ground rock so that a cavity is formed in ground rock. The cap is at least partially removed from lower discharge hole when hollow tube is then lifted from the formed cavity in order to perform passage of material through lower discharge hole to the cavity section released with hollow tube and lower head element. The latter has the form of cross section and the sizes which are more than the shape of cross section and sizes of hollow tube in order to decrease friction forces on hollow tube when penetrating into ground rock and being removed from it.

EFFECT: improving reliability of the pile and capacity and production effectiveness of piles.

34 cl, 26 dwg

FIELD: oil-and-gas.

SUBSTANCE: invention related to construction, particularly can be used for bored piles with enlarged base arrangement. The method includes hole boring, hole opening with mechanical clampshell enlarger, reinforced cage installation and filling in the hole with concrete mixture. Developing enlargement with ration of enlargement diametre to hole diametre, equal de/dh≥2 with rotation velocity equal n=20-100 revolution per minute, dependant on ground conditions. After covering distance 0.8 h, where h - height of enlargement, stop axial supply of boring media and at that level, during 3-5 revolutions execute enlargement base cleaning, and ground collector and voids between enlarger blades complete filling. Turn on axial supply and execute boring till enlargement total height and enlargement blades closure. Take away enlarger, then concrete enlarged base, install reinforced cage and complete bored piles arrangement with concreting its core.

EFFECT: method of bored pile arrangement efficiency increase and hole enlarger design improvement, hole enlarger reliability increase, easing of ground withdrawal out form ground collector and better quality of constructed bore pile.

4 cl, 3 dwg

Driven pile // 2386748

FIELD: construction.

SUBSTANCE: invention is related to construction, in particular to pile foundations. Driven pile consists of shaft with axial hole, sharpened tip with circular base and conusoidal shell with spike, cavities inside shell filled with hardening solution. There is a threaded hole in tip base, which is closed with threaded plug with stem. Tip shell is rumpled with submergence force after removal of threaded plug and additional submersion of pile. For additional increase of bearing capacity there is an elastic shell on lower part of shaft with facilities for fixation of its upper and lower ends; cavity between elastic shell and shaft surface; protective jacket with facilities of its fixation of shaft, which slides in radial direction and embraces elastic shell. There is a radial hole in shaft, which connects longitudinal hole with specified cavity transformed into support belt after the pile has been submerged at the specified depth, the cavity has been filled with hardening solution via holes in shaft and the solution has hardened.

EFFECT: improved bearing capacity of hollow piles.

4 cl, 7 dwg

FIELD: construction.

SUBSTANCE: method of drilled pile manufacturing includes well arrangement in soil. Supply of material into it. Compaction of soil under lower end of formed pile. In process of soil compaction, in the base of formed drilled pile with parametres equivalent to driven pile, its conventional camouflet cavity is arranged with diametre Dkp equal to diametre of dzs equivalent to driven pile, where: dzs - diametre (m) of equivalent driven pile. DkP - diametre (m) of conventional camouflet cavity produced in soil as it is displaced under lower end of formed drilled pile, by means of supply of controlled material volume to fill conventional camouflet cavity according to the following dependence : where V is controlled volume (m3) of material spent for filling of conventional camouflet cavity produced in soil due to its displacement into pile foundation. As well is filled with material in the form of hardening mix, preferably plastic concrete mix, diametre of equivalent driven pile is identified according to dependence , where dzs - diametre (m) of equivalent driven pile. Dskw - diametre (m) of well; Δh - measured value of subsidence (m) of plastic concrete mix in well as conventional camouflet cavity produced due to displacement of soil under lower end of formed pile is being filled. And in order to produce drilled pile with parametres of driven one of the same diametre, soil is treated in the lower end of pile till material subsides, preferably concrete mix, in well by value, which is compared with the one defined from the following ratio: Δh/Dskw=0.4. Besides in the lower end of well soil is exposed to forces, and their sufficiency is controlled (assessed) by flow of material additionally supplied to well in process of soil treatment, and its volume is identified according to formula , where Dskw - diametre (m) of formed pile. Besides in well reinforced with casing pipe, dynamic actions at soil are carried out until material subsidence value in casing pipe makes at least the following: , where Δhtr is subsidence (m) of material in casing pipe. Dskw - diametre (m) of well. Dfr - inner diametre (m) of casing pipe. Dynamic actions at soil in lower end of formed pile are carried out to achieve conventional failure, which is represented by material subsidence of not more than 2 mm in process of the last action, and when soils are compacted by electric explosions in pile foundation with application of electrode system, dynamic treatment is interrupted provided that electrode system freely installed on bottomhole in process of electric explosion sinks by not more than 1-2 cm, and in process of soil dynamic treatment at least one additional camouflet expansion is created along pile length, preferably, in zones of well opening of soils that are most pliant to compaction, which is detected by reaction of soil to test dynamic actions performed along pile length.

EFFECT: development of drilled piles with bearing capacity by soil, same as for driven piles, with minimum possible usage of resources and maximum possible usage of properties inherent in massif of soil that contains pile.

7 cl

FIELD: construction.

SUBSTANCE: device for compaction of soil in drilled pile well bottomhole includes casing pipe, bushing fixed on it with working element pulled through it. Working element is arranged in the form of hollow pipe, at the lower end of which there is a thrust journal and sealing attachment, and at the upper end there are upper and lower supports and inertial mass, placed on hollow pipe between upper and lower supports with sliding fit.

EFFECT: improved bearing capacity of drilled piles erected in watered and soft soils.

4 dwg

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