KR20210009509A - Cast-in-place pile using reinforced grouting and construction method - Google Patents

Abstract

The present invention relates to a construction method of an in-situ pile using reinforcing grouting. The construction method of an in-situ pile using reinforcing grouting comprises: a first step of excavating ground in a longitudinal direction which is a vertical direction with or without insertion of a casing; a second step of inserting a reinforcing bar cage including a reinforcing bar mesh including axial bars circumferentially separated from each other and installed in the longitudinal direction and stirrups binding the axial bars in a lateral direction which is a horizontal direction, and injection pipes coupled to the axial bars and the stirrups and installed in the longitudinal direction, wherein lower portions thereof are connected to each other, into an excavation portion of the ground; a third step of depositing concrete on the excavation portion of the ground by using a tremie pipe; and a fourth step of pressurizing and injecting grout into the ground by using the injection pipes after a prescribed time elapses from the concrete deposition. The steps are performed in the order listed above. The grout is pressurized and injected into the ground by using the injection pipes and injection rings after depositing concrete on the excavation portion of the ground by using the tremie pipe to carry out reinforcing grouting on loss end surfaces of concrete occurring in a sand gravel layer and a ground layer with running water flow to additionally reinforce the loss end surfaces to increase the bearing power of an in-situ pile, particularly the skin friction force of the pile.

Description

Cast-in-place pile using reinforced grouting and construction method}

The present invention relates to an on-site pile using reinforcing grouting and a construction method thereof, and in detail, by additionally pressurizing reinforcing grouting after the first concrete pouring, reinforcement for cross-sectional loss that may occur in the first concrete pouring and surrounding soft ground It relates to an in-situ pile using reinforcing grouting that can obtain a reinforcing effect for and its construction method.

In general, for the foundation work of a bridge, the direct foundation method, which installs the foundation by placing concrete directly on the bedrock, and the pile foundation method, in which a pile is mounted and installed to the bedrock are used.

In addition to the direct construction cost, the foundation work requires a large amount of construction cost and construction period, as the order wall construction in the groundwater eluting area and earth wall construction in the soft ground must be accompanied.

Therefore, in order to reduce construction costs and shorten construction period, installation work of order and earth walls, which are auxiliary works, during foundation construction, the application of the cast-in-place pile construction method is increasing.

The cast-in-place pile construction method includes a pull-out construction method in which a steel pipe casing is inserted up to the planned depth, excavated inside the casing, reinforced mesh is built, and concrete is poured using a tremi pipe, and the casing is pulled out to form a pile at the site. Using the casing as a permanent member, a reinforcing bar is installed inside the casing, and concrete is poured using a tremi pipe to form a pile, and the steel pipe casing is inserted to the planned depth and then the geo tube is included. There is a Geo tube method in which concrete is poured using a tremi pipe after reinforcing the reinforcing bar network to form a pile at the site.

All of the above methods are methods of pouring concrete using a tremi pipe, and a laitance layer is piled up at the top of the pile, so the laitance layer is removed after the concrete is poured and cured, and a subsequent process is carried out. This work is called "tofu cleaning". do.

Among the above construction methods, the pull-out construction method is carried out in the basement because the concrete can only be poured to the ground. If the head preparation is carried out underground, in the case of a groundwater elution area or soft ground, in order to secure the stability of the excavation surface There is a problem that it takes a lot of construction cost and construction period because the head should be rearranged after installing the order wall.

In order to solve the above problems, Korean Patent Registration No. 10-1664368 "Method of constructing by grounding the head trimming part of a cast-in-place pile using a geotube" is disclosed. This prior art is a method of constructing by making the head tidying part of the pile on the ground.The geotube is fixed and tied to a reinforcing bar network, and when concrete is poured, the geotube is used as a formwork, and concrete is poured so that the head tidying part is exposed on the ground. It is a technology that can reduce construction cost and construction period requirements by performing head trimming on the ground.

However, the prior art has a problem in that the structural stability of the cast-in-place pile is deteriorated due to the loss of the concrete cross section in the case of a stratum section in which flowing water flows through a sand gravel layer as concrete is placed inside the excavated ground by a tremi pipe.

Therefore, there is a need to develop a technique for constructing a cast-in-place pile that can reinforce the loss section of the concrete poured in the stratum section with flowing water through the sand and gravel layer and reinforce the surrounding soft ground.

Patent 1: Korean Patent Registration No. 10-1664368

In order to solve the above problem, the present invention is a concrete generated in a stratum with flowing water through a sand gravel layer by additionally pressurizing grout into the ground using an injection pipe after concrete is poured into the excavated part of the ground. By reinforcing the loss section of the pile, it is intended to provide an on-site pile using reinforcing grouting and its construction method, which increases the bearing capacity of the pile pile and the main surface friction of the pile.

In the in-place pile construction method using reinforcing grouting according to an example of the present invention, in the method for constructing an in-place pile using reinforcing grouting, the first step of excavating the ground in a vertical direction in a vertical direction without inserting a casing or inserting a casing ; Shaft reinforcing bars installed in the longitudinal direction while being spaced apart from each other in the circumferential direction, band reinforcing bars that bind the axial reinforcing bars in a horizontal direction in a horizontal direction, and injection pipes installed in the longitudinal direction by being coupled to the shaft reinforcing bar or the band A second step of inserting a reinforced cage containing into the excavated portion of the ground; A third step of pouring concrete into the excavated part of the ground; And a fourth step of pressurizing grout into the ground using the injection pipe after a certain period of time has elapsed from the concrete pouring; construction in order, and the lower portions of the injection pipes may be connected to each other.

In addition, the excavation of the ground in the first step may be characterized by excavating a part of the rock layer through the soil layer.

In addition, in the pressurized injection of grout in step 4, the grout is pressurized into the remaining injection pipes except for any one of the injection pipes, and when the grout overflows to any of the injection pipes, the grout is sealed, and the remaining injection pipes It may be characterized in that the grout is continuously pressurized through the pipe to pressurize the grout into the ground.

In addition, injection rings having a cylindrical shape are installed to be spaced apart from each other in the longitudinal direction, the injection rings communicate with the injection pipes, and the injection rings are provided with injection holes through which the grout is injected into the ground. can do.

In addition, it includes a connection T elbow for communicating the injection ring and the injection tube with each other,

The connection T elbow may include a vertical pipe coupled to the injection pipe on the upper and lower sides, and a pair of horizontal pipes protruding laterally from the vertical pipe and coupled to the injection ring.

In addition, it includes a non-return valve that is installed in the injection port to block the inflow of the concrete and enables pressure injection of the grout, and the non-return valve is inserted into the injection port and has a pipe-shaped body, an inner circumference of the body An inner locking jaw installed along the direction and caught on the inside of the injection hole, an outer locking jaw installed along the outer circumferential direction of the body and caught on the outside of the injection hole, a blocking plate blocking the body, and a part of the surface of the blocking plate It may be characterized in that it includes a cut-out portion that is cut in a cross shape to make it well cut.

In addition, it includes a tape that is installed at the injection port to block the inflow of the concrete and enables pressure injection of the grout, and the tape is overlapped and attached at the injection port, and then the overlapped area when the grout is pressed and injected It may be characterized by being injected while opening.

In addition, it includes a fiber cover that is installed to cover the injection port so as to be sealed to block the inflow of the concrete and enable the pressure injection of the grout,

The fiber cover may be installed on the injection ring by a pair of binding materials, and the fiber cover may be overlapped at the injection port and then injected while the overlapped portion is opened when the grout is pressed and injected.

Through the present invention, after concrete is poured into the excavated part of the ground, grout is additionally injected into the ground using an injection pipe to reinforce the loss section of the concrete generated in the strata with flowing water through the sand and gravel layer. It can provide an effect of increasing the bearing capacity of the cast pile and the main surface friction of the pile.

1A is a view showing a state in which a casing is installed and ground is excavated through a hammer grab or an auger.
1B is a view showing a state in which the ground, especially rock, is excavated using RCD or T4 equipment.
1C is a view showing a state in which a reinforcing bar cage and a reinforcing bar cage equipped with a grouting injection ring are inserted into the excavated ground.
1D is a view showing a state in which concrete is poured into the ground using a tremi tube while drawing a casing inserted in the ground.
1E is a view showing a state in which grout is pressed and injected through an injection pipe after a certain time has elapsed from concrete pouring.
1F is a view showing a state in which a post process is constructed by installing a column part and a coping part above the cast-in-place pile.
2A is a view showing a state in which grout is pressed into the ground through a configuration of an injection pipe, an injection ring, and a connection T elbow after concrete is poured.
2B is a three-dimensional view showing in detail a state in which an injection tube, an injection ring, and a connection T elbow are coupled to each other.
2C is a cross-sectional view showing AA in FIG. 2A.
2D is a view showing in detail the connection T elbow.
3A is a cross-sectional view and a detailed view showing a state of an injection ring equipped with a non-return valve according to an example of the present invention.
3B is a cross-sectional view and a detailed view showing a state of an injection ring with a tape installed as another embodiment.
3C is a cross-sectional view and a detailed view showing a state of an injection ring equipped with a fiber cover as another embodiment.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to elements of each drawing, the same elements are assigned the same numerals as possible even if they are indicated on different drawings. In addition, in describing an embodiment of the present invention, when it is determined that a detailed description of a related known configuration or function interferes with an understanding of the embodiment of the present invention, the detailed description thereof will be omitted.

In addition, in describing the constituent elements of an embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but another component between each component May be “connected”, “coupled” or “connected”.

With reference to FIGS. 1 to 3, a cast-in-place pile using reinforcing grouting according to an example of the present invention and a construction method thereof will be described in detail.

Referring to Figures 1 to 3, in the construction method for piles placed on site using reinforcing grouting according to an example of the present invention, in the construction method for piles placed on site using reinforcing grouting, inserting the casing 10 or inserting the casing 10 A first step of excavating the ground in a vertical direction in a vertical direction without; Shaft reinforcing bars 22 that are spaced apart from each other in the circumferential direction and band reinforcing bars that bind the shaft reinforcing bars 22 in the horizontal direction in the horizontal direction, and the shaft reinforcing bars 22 or the band reinforcing bars are coupled to the A second step of inserting the reinforced cage 20 including the injection pipes 24 installed in the longitudinal direction into the excavation portion of the ground; A third step of pouring concrete into the excavated portion of the ground using a tremi pipe; And a fourth step of pressurizing grout into the ground using the injection pipe 24 after a certain period of time has elapsed from the concrete pouring; it is constructed in order, and the lower injection pipes 24 may be connected to each other.

The first step is to excavate the ground. Step 1 is a step of inserting the casing 10 or excavating the ground in a vertical direction in a vertical direction without inserting the casing 10 to form an excavation hole for constructing an in-situ pile. In this step, excavation can be carried out using a hammer grab or auger. In this case, the casing 10 may be installed in order to prevent the collapse of the inner void wall. In addition, if there is no need, excavation may be performed without inserting the casing 10.

Referring to FIG. 1B, the excavation of the ground may be carried out to a part of the rock layer through the soil layer. The excavation of rock mass can also be carried out using RCD or T4 equipment. In this case, the lower part of the cast-in-place pile is supported by the rock layer, so that the support power of the pile can be improved.

Step 2 is a step of inserting the reinforced cage 20 into the excavated part of the ground. That is, this step is a step of preparing the construction of the cast-in-place piles as reinforced concrete piles by inserting the reinforced cage 20 into the excavation part of the ground. The reinforced cage 20 may be constructed as a reinforced concrete pile by being synthesized with concrete poured by a tremi pipe in the third step.

The reinforcing bar cage 20 includes axial reinforcing bars 22 installed in the longitudinal direction while being spaced apart from each other in the circumferential direction, and band reinforcing bars (including spiral reinforcing bars) that bind the axial reinforcing bars 22 in a horizontal direction in a horizontal direction, and It may include injection tubes 24 coupled to the reinforcing bar 22 or the band reinforcing bar. The injection tubes 24 may be installed in a longitudinal direction and have lower portions connected to each other.

Step 3 is a step of pouring concrete into the excavated part of the ground into which the reinforced cage 20 is inserted. At this stage, the concrete can be poured using a tremi tube or the like. Through this step, the concrete to be poured and the reinforced cage 20 inserted into the excavation portion of the ground may be synthesized and constructed as a reinforced concrete pile. Concrete pouring can proceed from the bottom to the top.

When the casing 10 is inserted, concrete can be poured while drawing the casing 10. That is, by allowing the concrete to be poured in the place where the casing 10 is drawn, the empty wall inside the ground may not collapse and the concrete can be easily poured. It is preferable that the drawing of the casing 10 follows the concrete to be poured.

Step 4 is a step of pressurizing grout into the ground. This step is a step of pouring the grout into the ground using the shaft reinforcement 22 or the injection pipe 24 coupled to the belt reinforcement after a certain period of time has elapsed after pouring concrete in the third step. In this embodiment, after 20 to 24 hours of concrete placement, that is, after the poured concrete has been hardened to some extent, grout may be injected. This is to ensure that the injected grout is not mixed with the poured concrete, but penetrates the concrete and is injected into the ground.

In the pressurized injection of grout, grout is pressurized into the remaining injection pipes 24 except one of the injection pipes 24, and overflowed when the grout overflows through any of the injection pipes 24 except for The pipe 24 is sealed, and the grout is continuously injected into the remaining injection pipes 24 to inject the grout into the ground.

That is, when the grout overflows so that no air is left inside the injection tube 24, the injection tube 24 is sealed and the pressure inside the injection tube 24 increases when the grout is injected under pressure. ), the inner grout is pressurized into the ground through an inlet to be described later. Injection holes may be formed in the injection tubes 24 to inject grout.

The injection tubes 24 may be provided with injection rings 26 having a cylindrical shape to be spaced apart from each other in the longitudinal direction. The injection rings 26 may be connected to each other in communication with the injection tubes 24. The injection rings 26 facilitate the movement of the grout by allowing the injection tubes 24 to communicate with each other, and the grout may be uniformly injected into the ground.

The injection ring 26 and the injection tube 24 may be in communication with each other by a connection T elbow 28. The connection T elbow 28 may include a vertical pipe coupled to the upper and lower injection pipes 24, and a pair of horizontal pipes protruding from the vertical pipe in the transverse direction and coupled to the injection ring 26. That is, the connection T elbow 28 may be coupled to the injection pipe 24 in the longitudinal direction by a vertical pipe, and may be coupled to the injection ring 26 by a horizontal pipe. It is preferable that the horizontal pipe is formed in the same curved shape as the injection ring 26. The vertical pipe of the connection T elbow 28 may be a part of the injection pipe 24, and the horizontal pipe may be a part of the injection ring 26.

Referring to FIG. 3A, injection holes 26 may be provided in the injection rings 26. The injection ports are configured to allow grout to be injected into the ground, and a non-return valve 262 may be installed at the injection port. The non-return valve 262 is installed at the injection port to block the inflow of concrete or the like poured into the ground into the inside of the injection ring 26, and allow the grout to be pressurized into the ground.

The non-return valve 262 is inserted into the inlet, and is installed in a pipe shape, along the inner circumferential direction of the body, and is installed along the inner circumferential direction of the inlet, and is installed along the outer circumferential direction of the body to the outer side. It may include a locking jaw, a blocking plate that blocks the body, and a cutout portion that cuts a portion of the surface of the blocking plate in a cross shape so as to be easily cut. That is, the non-return valve 262 is installed to be fixed to the injection port by the inner and outer locking jaws, and the concrete is blocked from entering the injection ring 26 by the blocking plate blocking the body, and the blocking plate When the grout is pressed, the cross-shaped cutout formed on the grout can be cut and opened easily, so that the grout can be pressed into the ground and injected. In addition, a plurality of cut lines may be formed inside the body of the non-return valve 262. This cut line can allow the non-return valve 262 to be easily inserted into the injection port. In addition, the inner locking jaw of the non-return valve 262 is formed to have a thin inner thickness so that it can be easily inserted into the injection port.

Referring to FIG. 3B, a tape 264 may be installed in the injection hole instead of a non-return belt. The tape 264 may be installed on the outside of the injection port to block the inflow of concrete and enable pressure injection of grout.

The tape 264 may be partially overlapped and attached to the injection port, and then, when the grout is pressurized, the overlapped and attached portions are opened and the grout may be pressurized into the ground. That is, it is preferable that the tape 264 has fewer overlapping portions so that the attachment portion can be opened. Also, the tape 264 may be attached and installed so that one of the tapes 264 blocks the injection hole. In this case, one side is thickly attached and the other side is thinly attached, so that the thinly attached side may fall and be injected under pressure.

Referring to Figure 3c, it is possible to install the fiber cover 266 so that the inlet is sealed. The fiber cover 266 may allow the injection port to be sealed, thereby enabling the pressure injection of grout while blocking the inflow of concrete.

The fiber cover 266 may be installed on the injection ring 26 by a pair of binding materials. The fiber cover 266 may be overlapped and installed at the injection port, and then, when the grout is pressed and injected, the overlapped portion is opened, and the grout may be pressurized into the ground.

The tape 264 or the fiber cover 266 can block the inflow of concrete inexpensively and conveniently, and at the same time enable pressure injection of grout.

Therefore, the grout can be pressurized into the ground through the injection rings 26 constituted by the above embodiments, and the grout injected into the ground reinforces the cross-sectional loss of the poured concrete, and at the same time reinforces the soft ground. By reinforcing it, the support force of the pile and the circumferential friction are increased, so that the structural stability of the cast-in-place pile can be increased.

After constructing the pillar part above the cast-in-place pile constructed through the above steps, and constructing the coping part above the pillar part, a subsequent process of the bridge construction may be performed.

In the end, through the above-described method of constructing a cast-in-place pile using reinforcing grouting, it is possible to firmly and easily install a cast-in-place pile on the ground with flowing water such as a sand gravel layer, so that the foundation work of a bridge can be constructed economically and efficiently. .

In the above, even if all the constituent elements constituting an embodiment of the present invention are described as being combined into one or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all the constituent elements may be configured or operated by selectively combining one or more. In addition, terms such as "include", "consist of" or "have" described above mean that the corresponding component may be present unless otherwise stated, excluding other components Rather, it should be interpreted as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined, to which the present invention belongs. Terms generally used, such as terms defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related technology, and are not interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

10: casing
20: rebar cage
22: shaft reinforcement
24: infusion tube
26: injection ring
262: non-return valve
264: tape
266; Fiber cover
28; Connection T elbow

Claims (9)

In the on-site pile construction method using reinforcing grouting,
Inserting the casing or excavating the ground in the vertical direction in the vertical direction without inserting the casing;
Shaft reinforcing bars installed in the longitudinal direction while being spaced apart from each other in the circumferential direction, band reinforcing bars that bind the axial reinforcing bars in a horizontal direction in a horizontal direction, and injection pipes installed in the longitudinal direction by being coupled to the shaft reinforcing bar or the band reinforcing bar. A second step of inserting a reinforced cage containing into the excavated portion of the ground;
A third step of pouring concrete into the excavated part of the ground; And
Step 4 of pressurizing grout into the ground using the injection pipe after a certain period of time has elapsed from the concrete pouring; construction in order,
The injection pipe is a method of constructing an on-site pile using reinforcing grouting in which the lower portions are connected to each other. The method according to claim 1,
The excavation of the ground in the first step is a method of constructing an on-site pile pile using reinforcing grouting, characterized in that the excavation of the ground passes through the soil layer to a part of the rock layer. The method according to claim 1,
In the pressurized injection of grout in step 4, the grout is pressurized into the remaining injection pipes except for any one of the injection pipes, and when the grout overflows to any one of the injection pipes, the grout is sealed, and the remaining injection pipes In-situ pile construction method using reinforced grouting, characterized in that the grout is continuously pressurized and the grout is pressurized into the ground. The method according to claim 1,
Reinforcement, characterized in that cylindrical injection rings are installed to be spaced apart from each other in the longitudinal direction, the injection rings communicate with the injection pipes, and injection holes through which the grout is injected into the ground are provided in the injection rings. Construction method for cast-in-place piles using grouting. The method of claim 4,
It includes a connection T elbow for communicating the injection ring and the injection tube with each other,
The connection T elbow includes a vertical pipe coupled to the injection pipe on the upper and lower sides, and a pair of horizontal pipes protruding in the transverse direction from the vertical pipe and coupled to the injection ring. How to construct piles. The method of claim 4,
And a non-return valve installed at the injection port to block the inflow of the concrete and enable pressure injection of the grout,
The non-return valve is inserted into the inlet and has a pipe-shaped body, an inner locking jaw that is installed along the inner circumferential direction of the body and caught on the inner side of the inlet, and is installed along the outer circumferential direction of the body to the outside of the inlet. An in-situ pile construction method using reinforcement grouting, characterized in that it comprises an outer stiffening jaw to hang on, a blocking plate that blocks the body, and a cutout that cuts a part of the surface of the blocking plate in a cross shape to make it well cut. The method of claim 4,
It is installed at the injection port and includes a tape that blocks the inflow of the concrete and enables pressure injection of the grout,
The tape is superimposed and attached at the injection port, and when the grout is pressurized and injected, the superimposed and attached areas are opened and injected. The method of claim 4,
It includes a fiber cover that is installed to cover the injection port to be sealed to block the inflow of the concrete and enable the pressure injection of the grout,
The fiber cover is installed on the injection ring by a pair of binding materials, and the fiber cover is installed overlapping at the injection hole and then injected while the overlapped portion is opened when the grout is pressed and injected. On-site pile construction method. In-place piles using reinforcing grouting constructed according to any one of claims 1 to 8.

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