RU2637002C1 - Method of arranging injection pile - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method for arranging an injection pile, according to which the well arrangement is carried out without excavation by means of pressing an injector pipe with a conical tip consisting of a disk and cutting plates, with simultaneously cutting longitudinal grooves on the well walls and forming a gap between the walls of a well to be made and the injector pipe. After immersing the injector pipe to the design mark, a hardening grout is injected under pressure into it, filling the arranged well with the grout, the soil area around the well and below being compacted. An unperforated injector pipe with a cylindrical widening at the bottom, the ends of which are chamfered towards the injection tube, forming the upper and the lower cones, is pressed into the soil. After immersing to the design mark, the injector pipe is removed from the well, leaving a tip in the well. Injecting the hardening grout is carried out simultaneously with extracting the injector pipe, filling the well with the hardening grout bottom-up. The soil area around the well is compacted while pressing and removing the injection pipe from the well with the surfaces of the lower and the upper cones of the injector pipe widening, respectively. After extracting the injector pipe, a reinforcement framework is immersed into the hardening grout.

EFFECT: increasing the carrying capacity of the foundation, manufacturability of its production in weak soils.

3 cl, 8 dwg

Description

The invention relates to the construction, in particular, to methods for constructing pile foundations mainly in soft soils, and can be used in industrial and civil construction both in strengthening the foundations of old, damaged or requiring reconstruction of buildings, and in the construction of new buildings and structures.

A known method of device injection piles, in which the device wells are produced without extracting soil. According to this method, the device of the well is carried out by pressing with the rotation of the tip, rigidly mounted on the rod of the drilling rig and having a diameter equal to the diameter of the borehole, while on the rod of the drilling rig is installed a hammer to which the tip is attached. Then fittings are installed in the well and hardened material is injected (Application RU No.2000117934 / 03, MKI 7 E02D 5/34, 5/44).

The advantage of this method is that the well is arranged without soil extraction - the tip mounted on the rod of the drilling rig is pressed into the soil with rotation, providing compaction of the soil at the base of the well. However, preliminary well formation is not excluded. This additional technological operation leads to an increase in the construction time of the injection pile and, as a result, to an increase in its cost. Moreover, in weak water-saturated soils, the stability of the walls of the well after its construction is not ensured. In addition, the compaction of the soil around the pile arranged in this way is not large enough, which affects the bearing capacity of the pile - it, in turn, is also not large.

There are other two methods of erecting a stuffed pile (ed. St. SU No. 1280084, E02D 5/34, publ. 12/30/86; ed. St. SU No. 1656928, E02D 5/34, publ. 12/15/93), in which the formation the pile shaft is carried out by first pressing a pipe with an annular extension tip while filling the resulting annular space between the pipe and the borehole wall with concrete. Then the pipe rises and the annular space inside the pipe is additionally filled with concrete mix according to ed. St. No. 1656928 and sand by bus. St. No. 1280084. Thus, the entire annular cross section of the pile is filled. The disadvantages of these two methods are the lack of subsequent expansion of the pile shaft (increase in diameter) along its length, as well as the formation of piles of annular cross-section with internal inclusion of soil, which does not provide high load-bearing capacity of the pile on the ground and on the material. The advantage is that the stability of the walls of the well is ensured by the simultaneous filling of the annular space around the pipe formed by pressing concrete mixture.

Two variants of the method for erecting injection piles according to patent RU 2263745, IPC E02D 5/34, E02D 5/46, publ. 11/10/2005. The method is used mainly for soft soils and includes immersion of casing with a lost tip and an injector pipe installed inside it. According to this method, the hardened mortar is injected stepwise along the length of the pile from bottom to top, first into the well zone between the tip and the lower stop installed in the casing. Then the casing together with the injector pipe is lifted and fixed. At the same time, an additional stop is installed on the injector pipe above the lower stop and, between the stops, this part of the injector pipe is perforated in one embodiment. A new zone is injected by injecting a hardening solution under pressure, and the operations are repeated until the casing is removed from the ground. The injection zone is set within a homogeneous soil, and the hardening mixture is supplied with a pressure determined for the soil of this zone. When the surface of the soil is additionally emphasized, the casing is removed and the perforated part of the injector pipe is left in the well. It performs the function of reinforcement. In the second embodiment, the injection pipe is performed without perforation and is removed completely from the well. The hardening solution is supplied only through the end hole of the injection pipe. In this embodiment, the reinforcing cage is placed between the stops and as the casing and injector pipes are removed, they are left in the well at the design level. The supply of a hardening mixture with a pressure that takes into account the characteristics of the soil, allows you to get a dense, uniform throughout the height of the pile and thereby increase its bearing capacity.

The disadvantage of this method is its low technology due to the many operations: immersion of the casing with the injector pipe installed inside it, their phased lifting, trimming the perforated part (1 option), installation of additional fittings (2 option). All this takes time and additional labor. In addition, in the cramped conditions of reconstruction, immersion and subsequent extraction of casing and injector pipes is an elusive, almost impossible task.

There is another method of injecting pile device, including the device of the well without removing the soil by pressing the injector pipe with a cone tip into the soil and injecting a hardening solution under pressure through the injection pipe after it reaches the design mark and plugging the wellhead. The injection tube is perforated with holes along the entire length with a conical tip fixed to the lower end, consisting of a disk, a diameter larger than the diameter of the injection pipe and cutting inserts, the edges of which protrude beyond the base of the disk. When an injector with a tip of this design is pressed in, longitudinal grooves are cut on the walls of the well and a gap is formed between the wall of the well and the injector pipe. The gap is necessary to reduce the force of the indentation when immersing the injection pipe and further uniform expansion of the walls of the well when injecting a hardening mixture. When injecting a hardening solution, the walls of the well become denser. The injection pipe after the injection of the hardening solution and the formation of the pile shaft remains in the pile body and acts as a reinforcement. Pile trunk during injection is formed in the form of a vertical rod with a wavy side surface (US Pat. RU No. 2238366, IPC E02D 5/34, publ. 20.10.04). The specified method is closest to the claimed and adopted as a prototype.

The disadvantage of this method is the ability to melt (collapse) the walls of the well in soft soils at the stage between the formation of the well and the injection of the hardening mixture, which negatively affects the formation of a continuous, uniform cross section of the constructed pile, its bearing capacity and manufacturability during execution. Another disadvantage is the need for plugging the wellhead, and the injection pipe, which remains in the body of the pile and acts as a reinforcement, greatly increases the cost of the device injection piles.

The technical problem solved by the invention is the formation of a continuous, uniform cross section of the pile shaft with an increase in its bearing capacity and manufacturability in soft soils.

The technical problem is solved by the invention as follows.

As in the method of injecting pile device adopted for the prototype, the device of the well according to the claimed method is produced without extracting soil by pressing an injector pipe with a conical tip consisting of a disk and cutting plates into the soil while cutting longitudinal grooves on the walls of the well and forming a gap between the walls of the well being formed and the injection pipe. After the injector pipe is immersed to the design level, a hardening solution is injected into it under pressure, filling the well constructed with the latter. As in the prototype, the soil area around the well is compacted.

Unlike the prototype according to the invention, an unperforated injector pipe with cylindrical broadening in the lower part is pressed into the ground. The ends of the broadening are beveled towards the injection pipe, forming the upper and lower cones. After the injection pipe is submerged to the design level, it is removed from the well, leaving a conical tip in the well. Unlike the prototype, the injection of the hardening solution is carried out simultaneously with the extraction of the injector pipe, filling the well with the hardening solution from bottom to top. The difference is also that the soil zone around the well is compacted when the injector pipe is pressed in and when the injector pipe is removed from the well by the surfaces of the lower and upper cones of its broadening, respectively. After removing the injector pipe, the reinforcing cage is immersed in the hardening solution.

Due to the use of widening of the injector pipe, in the manufacture of piles, the device of tamping and weights is not required to prevent the outflow (exit) of the hardening mortar to the surface, which increases the manufacturability of the method.

In special cases, an additional expansion of the sections of the pile shaft is carried out by increasing the pressure or time of injection of the hardening mortar in these areas, and also after the device is installed along the entire length of the pile, pressure testing of the near pile soil mass is carried out with high pressure.

Pile according to the claimed method is formed in the form of a vertical rod with a wave-like lateral surface with a broadening of the trunk in the area of soft soil. By adjusting the volume of injected hardening mortar by increasing pressure or injection time, it is possible to provide broadening of different diameters along the length of the pile shaft, taking into account the properties of soils.

The use of the totality of the declared features in the manufacture of injection piles provides a solution to the technical problem of ensuring the formation of a continuous section of the pile shaft, increasing its bearing capacity and manufacturability in weak soils.

The formation of a continuous, uniform cross section of the pile shaft is ensured by the simultaneous filling of the formed well with a hardening mortar (concrete mix) as the injector pipe is removed. The broadening and the upper cone prevent soil from entering the hardening solution and condense the walls of the well when removing the injector pipe from the well. The increase in the bearing capacity of the piles is ensured by the formation of additional broadening of the trunk in the area of soft soil with simultaneous compaction of the soil. The combination of all operations on the device of the pile is made by one equipment, operations on its rearrangement and change are excluded, the operation on the device of tamping and weights is excluded, which increases the manufacturability of the manufacture of piles.

The applicant does not know the methods of device injection piles containing the totality of all the claimed features and characterizing the invention. This confirms the novelty of the invention. The prior art does not reveal the injection of a hardening solution through the injector pipe from the bottom up with the simultaneous extraction of the injector pipe and the compaction of the walls of the well with broadening and cones of the injector pipe. Explicitly, the method does not follow from the prior art, which confirms the presence of an inventive step.

Next, the method of device injection piles is illustrated by an example of a specific implementation.

In FIG. 1 shows the lower part of the injector pipe with broadening; in FIG. 2 shows a lost tip; in FIG. 3-7 - technological schemes of a phased device for injection piles according to the proposed method; in FIG. 8 shows an injection pile arranged by the proposed method with a plot of soft soil.

The method of device injection piles is as follows.

An injection pipe (1) is installed on the soil surface, consisting of a steel pipe with cylindrical broadening in the lower part (2) and bevels towards the injection pipe, which form cones in the lower and upper directions (3, 4), at the end of which there is a lost tip (5) having a lock (6), a disc (7) and cutting inserts (8). Then, the injector pipe (1) with the lost tip (5) is immersed in the ground with the help of pressing equipment or a vibration absorber (not shown) by pressing force N1 to a predetermined depth. During the dive, a well is formed. Due to the broadening (2) in the lower part of the injection pipe (1), friction along the lateral surface and, consequently, the indentation force are reduced. Due to the cone (3), the walls of the well (9) are compacted in the lower direction by extruded soil. With this method of the device, soil (10) can enter the gap between the borehole wall (9) and the injection pipe (1). Then, a hardening concrete mortar (11) is injected into the formed well under pressure P1 through the injection pipe (1). As the well is filled with solution (11), the injection pipe (1) is removed with a force of N2, while the tip (5) remains in the ground. This method is applicable when installing injection piles in weak (water-saturated) soils. It is also possible to increase the diameter of the well (12) in the weak pound area by increasing the supply pressure P1 of the hardening mixture (11). This increases the bearing capacity of piles in soft soils. When the injector pipe (1) is removed, the soil (10) caught in the gap is pressed into the borehole walls (9) with the cone (4) in the upper direction. After concreting and extraction of the injection pipe (1), the reinforcing cage (13) is immersed in the well. If necessary, crimping a near pile pile of soil with high pressure is performed.

The proposed method provides the formation of a continuous section of the pile shaft by filling the formed well with a hardening (concrete) mixture. The increase in the bearing capacity of the piles is ensured by the formation along the length of the shaft of the pile of additional broadening over the diameter of the well with soil compaction. The combination of all operations on the installation of piles is carried out by one equipment, the operations of its rearrangement and change are excluded, the need to plug the well (grouting) and the device of the load is excluded, which increases the manufacturability of the manufacture of piles.

Claims (3)

1. The method of device injection piles, according to which the device is produced without removing the soil by pressing into the soil of the injection pipe with a conical tip, consisting of a disk and cutting plates, while cutting longitudinal grooves on the walls of the well and forming a gap between the walls of the formed well and the injection pipe , after the injector pipe is immersed to the design level, a hardening solution is injected into it under pressure, filling the well constructed with the latter, and the soil zone around the wells the bottom is compacted, characterized in that an unperforated injection pipe with cylindrical broadening in the lower part is pressed into the ground, the ends of which are beveled towards the injection pipe, forming upper and lower cones, and after the injection pipe is submerged to the design mark, it is removed from the well, leaving the tip in the well, and injection of the hardening solution is carried out simultaneously with the extraction of the injection pipe, filling up the well with the hardening solution from bottom to top, while the soil zone around the well they are compacted by pressing and when removing the injector pipe from the well by the surfaces of the lower and upper cones of widening the injector pipe, respectively, in addition, after removing the injector pipe, the reinforcing cage is immersed in the hardening solution. 2. The method of injection piles according to claim 1, characterized in that they further expand the pile shaft in areas of soft soil by increasing the pressure or time of injection of the hardening solution in these areas. 3. The method of construction of an injection pile according to claim 1, characterized in that during the construction of the pile along its entire length, pressure testing of the near pile soil mass is carried out with high pressure.

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