RU2023110C1 - Driven pile - Google Patents

Abstract

FIELD: construction. SUBSTANCE: average projection area on horizontal plane of driven pile overlying widened parts exceeds the area of projection on the horizontal plane of lower widened part by 1.2 times. Widened parts are spaced over pile height from one another at average distance equalling (10-60)b, where b is departure of overlying widened part, and departure of lower widened part does not exceed 1/2 of diameter of pile or width of face carrying widened part. Widened parts may be made on lower sections of one or two side faces of pile and faces may be inclined towards pile lateral axis. EFFECT: higher efficiency. 4 cl, 10 dwg

Description

 The invention relates to construction, namely to pile foundations and can be used in the construction of residential, public and industrial buildings and structures.

 Known driven piles with broadening at the lower end, the so-called club-shaped. Such short (3-5 m long) piles have increased bearing capacity in flooded weak clay soils with the lower end of the trunk resting on more solid base layers [1].

 However, the known piles have a number of significant drawbacks. It is known that short piles have a limited area of application for soil conditions due to the low bearing capacity from the conditions of permissible deformations of the bases and uneven settlement of foundations. And with an increase in the length of the club-shaped pile, its specific bearing capacity decreases, since with the increase in the length of its trunk, the lateral surface area increases. And in club-shaped piles, the load on the foundation soil is not transmitted through the lateral side from the broadening side, since voids form on the side of these faces.

 Subsequently, voids (sinuses) along the lateral surface of the trunk from the side of the broadening are filled with soil in a loosened state. Thus, the adhesion between the soil and the indicated lateral surface of the pile is practically absent, which leads to a decrease in the bearing capacity of the known pile.

 Since the club-shaped piles have a developed area along the lower end, it is advisable to base such a pile with its lower end on deeper, strong layers of the base. In this case, it is difficult to drive such piles, since with an increase in the area of the pile along the lower end, the resistance to penetration of the trunk sharply increases. This is due to the fact that when driving the foundation, the mass of soil displaced by the pile is pushed to the side outside the area of the polygon bounded by the lower end of the trunk. Significant force is required to drive the soil to the sides. The greater the distance from the center of the lower end to the lateral faces of the pile shaft or its broadening, the more intensively the resistance of the pile shaft to immersion increases, which leads to excessive energy consumption for pile immersion.

 In addition, often the destruction of the shaft of the club-shaped pile under the influence of the impact force necessary for its immersion is often observed. This also leads to a decrease in the bearing capacity of the known driven pile. To increase the strength of the barrel spend a significant amount of high-quality cement and steel.

 These shortcomings hinder the widespread use of known piles.

 The closest technical solution to the invention in terms of its technical nature and the achieved result is a driven pile, including a shaft with a tip with broadening located in tiers along its height at a distance from each other [2].

 However, the known pile has a number of significant drawbacks. When a known pile is immersed along its trunk, a leading well is formed with a cross-sectional area equal to the projection area onto the horizontal plane of the cross-section of the trunk in the lower broadening zone. With further immersion of a known pile, its trunk with overlying broadening plunges into the formed well. In this case, soil adhesion to the lateral surface of the pile trunk occurs only along the vertical faces of the broadening. And through the lower faces of the overlying broadening and through the lateral surface of the trunk in the areas between the broadening, the load from the pile to the foundation soil is practically not transmitted, which leads to a decrease in the bearing capacity of the known pile.

 Therefore, the use of such piles is sometimes appropriate in flooded clay soils in a fluid state. However, such base soils have low bearing capacity, especially based on deformations, which also reduces their bearing capacity and the scope of known piles.

 The disadvantages of the known piles during its operation in subsiding soils also appear. Since when they are soaking, their subsidence occurs, then in the sections of the trunk between the broadening, the walls of the well are destroyed and the soil is displaced to the side surface of this section of the trunk. In this case, the soil transfers an additional load (a load equal to the own weight of the near-pile soil) to the pile through the upper edges of the broadening, which also reduces the bearing capacity of the known pile.

 In addition, when a section of the trunk with broadening is buried in subsidence soil layers, a significant friction force develops along the lateral surface of the broadening, which prevents the pile from sinking, which leads to significant energy consumption during the sinking process.

 The purpose of the invention is to increase the specific bearing capacity and reduce energy consumption during the dive.

 In FIG. 1 shows a driven pile, general view; in FIG. 2 is a view along arrow A in FIG. 1; in FIG. 3 - general view of the pile, an embodiment; in FIG. 4 is a view along arrow B in FIG. 3; in FIG. 5 - general view of the pile, an embodiment; in FIG. 6 is a view along arrow B in FIG. 5; in FIG. 7 - General view of the piles, an embodiment; in FIG. 8 is a view along arrow D in FIG. 7; in FIG. 9 - General view of the piles, an embodiment; in FIG. 10 is a view along arrow D in FIG. 9.

 The pile includes head 1, trunk 2, lower broadening 3 and overlying broadening 4, 5, 6, located along the height of trunk 2 at an average distance from each other in the range (10-60) b, where b is the overhang of the overlying broadening, and the average area projections (the total area of the overlying broadening is divided by the number of broadening) on the horizontal plane of the broadening located above the lower broadening in the trunk section, not exceeding 2/3 of its height, exceeds not less than 1.2 times the projection area on the horizontal plane of the lower broadening. Broadening can be performed on the lower sections of one or two side faces of the trunk. At least two lateral faces 7 of the barrel 2 can be made inclined to the transverse axis of the barrel, while the broadening is located on the inclined faces of the barrel.

 The pile works as follows. When immersing the lower section of the pile trunk, a certain volume of soil is displaced equal to the volume of the immersed part of its trunk. Most of the soil mass from the space into which the trunk section has been embedded is forced out beyond the boundaries of the lower end face, i.e., to the side faces of the pile. In turn, the soil displaced outside the trunk transfers pressure to the soil particles surrounding the pile and receives some compaction. But at this moment, the bonds between the particles of soil surrounding the pile are broken.

 With further immersion of the pile into the array of near-pile soil, a section of the trunk with broadening 3 is introduced.

 Since the bonds between the soil particles in the near pile pile are destroyed, less effort is required to introduce broadening of 3 pile piles into the near pile pile. In turn, the broadening 3 is immersed in the soil, compacted by immersion of the lower section of the trunk. Therefore, the soil from the lower faces of the broadening and from the side of the lateral surface of the pile shaft receives additional compaction.

 With further immersion of the pile, the overlying broadening comes into contact with the soil 4. Since the projection area onto the horizontal plane of the overlying broadening is larger than the projecting area of the lower broadening, the overlying broadening is embedded in a compacted array of near pile soil. In the process of immersion of the overlying broadening in the near-pile soil, the soil is crushed into the well formed by the introduction of the underlying broadening. With further submersion of the pile, the degree of compaction of the near-pile soil in the area between the broadening increases, which leads to an increase in the adhesion force of the soil to the side surface of the pile and the soil reactive resistance to the lower faces of the broadening increases, which ensures an increase in the specific bearing capacity of the pile.

 At the last stage of pile immersion, the upper broadening overlaps in plan the space between the soil and the side faces of the trunk, which was formed as a result of the introduction of the underlying broadening into the ground. The soil displaced by the upper broadening fills this space. With further immersion in the soil of the upper broadening, compaction of the near-pile soil occurs.

 Due to the fact that the projection area on the horizontal plane of the overlying broadening exceeds the projection area on the horizontal plane of the lower broadening, the presence of compacted soil is ensured, both in the zone of its adhesion to the lateral surface of the trunk in the areas between the broadening, and in the contact zone of the lower and lateral faces of all broadening.

 Since the lower and lateral faces of all broadenings interact with compacted soil, transferring the load from the pile at different levels to the base soil, this increases the specific bearing capacity of the pile and the reliability of its operation.

 Since the broadening is located at a distance from each other, equal to (10-60) b, where b is the overhang of the overlying broadening, there is a dissipation in the near pile pile of soil transmitted through these broadening of the load on the base soil from the pile and thereby excluding the cut of the soil along the trunk within the projection area of the overlying broadening. In this case, the lower edges of the broadening interact with the base soil as the frontal surface of the pile (as the lower end of the pile).

 Thus, the specific bearing capacity of the pile increases and the rigidity of embedding the pile in the soil increases, which simultaneously provides an increase in the bearing capacity of the pile by the deformations of its base.

 The upper sections of piles operating in subsiding soils must be performed without broadening. In this case, a gap between the soil and the side surface of the pile is formed in the trunk section above the upper broadening when driving the pile. The presence of a gap between the soil and the side surface of the pile in the thickness of the subsiding soil layer reduces energy consumption when immersing the pile, since there is no friction on the side surface in this section of the trunk, which facilitates the immersion of the pile.

 In this case, at the same time, an increase in the bearing capacity of the pile is achieved, since there is practically no negative friction during subsidence of subsidence soil.

Claims (4)

 1. Piled pile, including a heading shaft with broadening, located in tiers along its height at a distance from each other, characterized in that in order to increase the specific bearing capacity by increasing the degree of compaction of near-pile soil along the pile shaft and reducing energy consumption in the process diving mainly in subsidence soils, the average projection area on the horizontal plane of the broadening located above the lower broadening in the trunk section, not exceeding 2/3 of its height, exceeds not less than 1 , 2 times the projection area on the horizontal plane of the lower broadening.  2. A pile according to claim 1, characterized in that the broadening is made in the lower sections of one or two side faces of the trunk.  3. A pile according to claims 1 and 2, characterized in that at least two lateral faces of the trunk are made oblique to the transverse axis of the trunk, and the broadening is located on the inclined faces of the trunk.  4. The pile according to paragraphs. 1 - 3, characterized in that the broadening is located along the height of the barrel at a distance from each other (10 - 60) b, where b is the overhang of the overlying broadening, and the overhang of the lower broadening does not exceed 1/2 of the trunk diameter or the width of the face on which broadening.

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