JPH0610344A - Confirmation and increase method for support force of cast-in-place pile - Google Patents

Abstract

PURPOSE:To achieve confirmation of the support force of a cast-in-place pipe and the increase of the support force of a tip ground through a low-cost device. CONSTITUTION:A cylindrical auxiliary device 10 is installed to the bottom part of a pile hole H, the lower end of a press-in pipe 30 is positioned in the middle of the internal height of the auxiliary device 10, and concrete is placed in the pile hole H to build a cast-in-place pile 40. After curing of the pile 40, curable fluid 50 is pressed in through the press-in pipe 30 to divide the tip part of the pile into upper and lower sections. The tip ground is consolidated through peripheral surface friction of the pile 40 serving as a reaction force to increase a support force, and the support force is confirmed by means of the current press-in force of fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cast-in-place pile, and more particularly to a method for confirming the supporting force of a cast-in-place pile to be constructed and increasing the tip supporting force.

[0002]

2. Description of the Related Art As is well known, cast-in-place piles are constructed by excavating a pile hole in advance, inserting a reinforcing bar cage into this pile hole, and then placing concrete to support it. It is difficult to confirm the force. In addition, when excavating a pile hole, earth pressure is released and the tip ground loosens, and sediment easily accumulates, and the pile after construction will sink over time, that is, the quality of the constructed pile is high. There was a risk of defects.

Conventionally, as a method of confirming the supporting force of the constructed pile, a load test is known in which a plurality of piles are used as reaction piles and a load to be tested is applied with a hydraulic jack or the like (hereinafter, referred to as a load test). "Conventional loading test"). On the other hand, as a simple loading test, a jack device is installed at the tip of the test pile, that is, the bottom of the pile hole, and the jack device is driven after the pile is constructed, and the tip supporting force and the pile peripheral surface friction force are measured. It is known that a load test can be easily performed without using a reaction force pile (for example, JP-A-61-225628,
Hereinafter, such as JP-A-62-291333, "simple loading test").

On the other hand, as a means for strengthening the ground at the tip of the pile to increase the bearing capacity of the pile after construction and preventing settlement, for example, a reaction force is taken by a hole wall or a casing pipe before construction of the pile. A method is known in which a large number of rod-shaped rigid bodies or cone blocks divided into concentric circles are pushed into the bottom of the hole with a jack or the like to improve the tip supporting force (for example, JP-A 1-223214, JP-A 2-23214). No. 24415).

Further, after a rubber bag or a jack housed in a restraint container is installed at the bottom of the hole, a cast-in-place pile is formed, and a pressure fluid is injected into the rubber bag or jack from the ground to inflate it, and the peripheral surface of the pile is A method is known in which friction is used as a reaction force to consolidate the tip ground and improve the supporting force (for example, Japanese Patent Laid-Open No.
125015, JP-A-3-90706, etc.). In addition, multiple pipes are installed over the entire length of the pile hole, and after the pile is constructed, a hardening agent is pressed into the hole bottom through the multiple pipes to harden the hole bottom ground and slime and improve the bearing capacity. A method of doing this is known (for example, JP-A No. 2-4724).

[0006]

However, in the above-mentioned conventional load test, in addition to the need for a plurality of reaction force piles, it is necessary to attach a load beam or a jack to the reaction force piles.
Since preparation and removal require time and effort and cost is high, it is the current practice that the certification method is not used to check the bearing capacity or only one of the many methods is checked. Is.

Further, the simple loading test is effective in that it takes less time and labor as compared with the conventional loading test described above, but the expensive jack device cannot be recovered, and the supporting force of all the piles constructed is high. It is still unreasonable in terms of cost to confirm the above, and at present, it is regarded as a promising alternative technique to the conventional loading test. On the other hand, in the conventional method of pushing in the rigid body or the cone block (for example, JP-A 1-223214, JP-A 2-24415, etc.), a large-scale device for pushing in the rigid body or the cone block is required, and before the construction of the pile. Since the piles will be created after going to, there is a risk that the number of steps will increase and the cost will increase.

Further, in the conventional method using a rubber bag or a jack (for example, Japanese Patent Laid-Open Nos. 2-125015 and 3-90706), the number of steps can be reduced, but an expensive device such as a jack is required. There are drawbacks. Furthermore, a conventional method of press-fitting a curing agent with a pipe into the hole bottom ground and slime (for example, Japanese Patent Laid-Open No.
2-4724, etc.), the structure is extremely simple, so it can be expected to be inexpensive, but if there is a sand layer or water vein near the tip ground, the hardened agent injected will flow out to the sand layer or water vein with low pressure. It is considered that the tip ground cannot be strengthened.

Although the above-described method for confirming the supporting force of the pile and the method for increasing the supporting force of the pile each have their own characteristics, the purpose is to still require an expensive device or to achieve only one of them. Many of them cannot be used as a series of methods to confirm the bearing capacity of all or most of the piles constructed and to increase the bearing capacity. Therefore, the method of confirming and increasing the bearing capacity of the cast-in-place pile according to claims 1 to 5 is made in view of the problems of the above-mentioned conventional techniques, and the supporting force of the cast-in-place pile can be easily and inexpensively. By providing a confirmation method and an increasing method, it is possible to confirm the bearing capacity of all or most of the cast-in-place piles to be formed, and at the same time to increase the tip-end supporting force, thereby creating a high-quality cast-in-place pile. And

That is, in the method according to claim 1, a simple and inexpensive device is simply installed in the pile hole before forming the cast-in-place pile, and after the pile is hardened, the support force can be easily confirmed and the tip support force can be confirmed. The purpose is to increase. The method according to claim 2 is
In addition to the object of the method according to claim 1 described above, in particular, when the tip of the pile is fractured and divided up and down by the pressure of fluid in the tubular auxiliary device, the tip of the pile can be divided easily and horizontally. Is to

According to the method of claim 3, in addition to the object of the method of claim 1 or 2, the auxiliary device and the reinforcing bar are fixed to the lower end portion of the reinforcing bar cage by means such as welding in advance. The basket can be installed in the pile hole at the same time.
The purpose is to reduce labor and the number of steps. In addition to the object of the method according to claim 1 or 2, the method according to claim 4 is intended to be provided at low cost by using the press-fitting pipe as a part or all of the main bars of the reinforcing bar cage.

According to the method of claim 5, in addition to the object of the method of claim 2, the partition plate is provided with an opening which communicates with the upper and lower sides, so that at the time of pouring concrete, the concrete also passes through the opening to the lower part of the partition plate. The purpose is to make it possible to drive and to prevent the formation of cavities below the partition plate.

[0013]

The present invention is to achieve the above-mentioned object, and the contents thereof will be described below with reference to the embodiments shown in the drawings. The method according to claim 1, wherein a tubular auxiliary device (10) having substantially the same diameter as the pile hole (H) is installed at the bottom of the pile hole (H), and the lower end of the press-fitting pipe (30) is an auxiliary device.
It is located in the middle of the internal height of (10), concrete is placed in the pile hole (H) to form the pile (40), and after the pile (40) hardens, it hardens through the press-fit pipe (30). Fluid (50) of the pile is pressed at the required pressure and the tip of the pile in the auxiliary device (10) is divided into upper and lower parts by the pressure input, and the tip ground is compacted by using the peripheral friction of the pile (40) as a reaction force. It is characterized by increasing the supporting force and confirming the supporting force by the pressure input of the fluid (50).

According to the method of claim 2, a cylindrical auxiliary device (10) having substantially the same diameter as the pile hole (H) is installed at the bottom of the pile hole (H), and the diameter is smaller than the inner diameter of the auxiliary device (10). Position the press-in pipe (30) with the partition plate (70) at the lower end of the partition plate (70) in the middle of the internal height of the auxiliary device (10), and place concrete in the pile hole (H) to mount the pile (40). After building and hardening the pile (40), a hardening fluid (50) is pressed in at a required pressure through the press-fitting pipe (30), and the pressure input causes the tip of the pile to be a partition plate inside the auxiliary device (10). It is divided into upper and lower parts at the position, and by using the friction of the peripheral surface of the pile (40) as a reaction force to consolidate the tip ground and increase the supporting force, the supporting force can be confirmed by the pressure input of the fluid (50). To do.

The method according to claim 3 is characterized in that the auxiliary device (10) comprises:
It is characterized in that it is fixed to the lower end of the rebar cage (20). In the method according to claim 4, the press-fitting pipe (30) is a rebar cage.
It is characterized in that it also serves as the main line (21) of (20). The method according to claim 5 is characterized in that the partition plate (70) has an opening (71) communicating with the upper and lower sides.

[0016]

According to the method of claim 1, the tip of the pile is broken up and down by the pressure of the fluid (50) in the cylindrical auxiliary device (10) without the need for an expensive jack or the like. The auxiliary device (10) acts as a cylinder, and the divided pile tip end upper part (41) or lower part (42) acts as a piston, and a hardening fluid (50) such as cement mortar is pressed into the gap. Then, using the peripheral friction of the pile (40) as a reaction force, the lower part (4
2) is lowered by the pressure of the fluid (50), and the tip ground can be consolidated to increase the supporting force. If the pressure of the fluid (50) reaches or exceeds the predetermined pressure, it can be estimated that the required tip resistance has been obtained. In other words, the bearing capacity of the pile (40) can be confirmed.

In most cases, the peripheral friction is larger than the tip resistance, so that the tip ground can be compacted within the reaction force of the peripheral friction of the pile (40) to obtain the required tip resistance. However, it is conceivable that the pile head is lifted up by the pile (40) itself being pushed up before the pressure of the fluid (50) reaches a predetermined pressure because the pile length is short or the surrounding ground is soft. In such a case, once measure the floating displacement of the pile (40) and the pressure input and press-fit amount of the fluid (50), calculate the bearing capacity and sinkage of the pile (40), and re-evaluate the bearing capacity. It is advisable to carry out or use a plurality of piles in the vicinity as reaction force piles and press-in the fluid (50) again until the pressure of the fluid (50) reaches a predetermined pressure.

The object and the means of the method according to claim 2 are substantially the same as the method according to claim 1 described above, but vertical cracks are generated when the tip of the pile is broken by the pressure of the fluid (50). A partition plate (70) with a diameter smaller than the inner diameter of the auxiliary device (10) is used as a means to easily and horizontally divide the pile tip into upper and lower parts without causing it, and at the lower end of the press-fit pipe (30). It is attached. That is, the tip of the pile is gradually destroyed by the press-fitting of the fluid (50) from the press-fitting pipe (30), and finally a crack is generated and the partition plate (70) is divided.
By attaching the, the partition plate (70) becomes the starting point of the crack, the crack spreads along this partition plate (70), and at the end, the tip of the pile can be easily split up and down without waste. is there. Therefore, the partition plate (70) may be of any material, shape, and size as long as it serves as a starting point for causing a crack in the pile tip portion, but is preferably deformable like a polystyrene foam plate or a rubber plate. Partition plate (7
0) It is good to stack on the lower surface. In other words, the press-fitting of the fluid (50) causes the Styrofoam plate, etc. to shrink and deform,
Since the flow path of the fluid (50) is formed, cracks can be caused more smoothly in the tip portion of the pile.

Here, the auxiliary device (10) is a device that does not easily undergo deformation such as expansion due to the planned pressurization of the hardening fluid (50), for example, a tough steel pipe, Its size is such that it can be easily inserted and installed in the pile hole (H),
In other words, the diameter should be slightly smaller than the pile hole (H), and its length must be at least the stroke of the upper part (41) or the lower part (42) of the pile tip that acts as a piston, but is not limited to 50- About 150 cm is preferable. Furthermore, auxiliary equipment (10)
The inner surface of the pile slides the upper part (41) or the lower part (42) of the pile tip as a piston, so it needs to be smooth, and in order to facilitate separation from concrete, a release agent or It is advisable to apply a resin paint or attach a thin film resin. Further, when only the lower portion (42) of the pile tip portion is made to act as a piston, the lower portion of the lower end of the press-fitting pipe (30) may be made smooth and the upper portion may be made into a concavo-convex surface so that the concrete adheres thereto.

In the method according to claim 3, the fixing means is not particularly limited, but for example, the auxiliary device (10) is formed to have substantially the same diameter as the rebar cage (20), and the lower end number of the rebar cage (20). It is advisable that one centimeter to several tens of centimeters are placed along the inner surface or outer surface of the auxiliary device (10), welded and fixed, and both are integrated. When the auxiliary device (10) and the reinforcing bar cage (20) are integrated as described above, only the lower portion (42) of the pile tip portion acts as a piston.

The method according to claim 4 is the press-fitting pipe (3
As long as 0) can withstand the pressure input of the fluid (50), it can be used regardless of the material, such as metal pipes and vinyl chloride pipes. Especially when a metal pipe is used, it can also be used as a part or all of the main bar (21) of the reinforcing bar cage (20). The method according to claim 5 is characterized in that the partition plate (70) has an opening that vertically communicates with the partition plate (70) such as a mesh shape or a cage shape, and the concrete to be placed passes through the opening to form the partition plate. It can be set so that it can be placed below (70).

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the method for confirming and increasing the bearing capacity of a cast-in-place pile according to the present invention will be described below with reference to the embodiments shown in the drawings. 1 to 3 show a first embodiment of the present invention, and FIG. 1 (a) shows an auxiliary device used in the method of the present invention,
FIG. 2 (b) is an explanatory view showing the construction of a pile, and FIG. 3 is an explanatory view showing a press-fitted state of a fluid. Is.

In FIGS. 1 (a) and 1 (b) to 2, reference numeral 10 denotes an auxiliary device used in this method.
It is formed of a steel pipe having a diameter slightly smaller than the diameter of the pile hole H and is fixed to the lower end portion of the reinforcing bar cage 20. As shown in FIGS. 1 (a) and 1 (b), the rebar cage 20 is composed of a longitudinal main bar 21 and a hoop bar 22. The outer diameter of the rebar cage 20 is the auxiliary device 10
Is smaller than the inner diameter of, the lower end of the rebar cage 20 is several centimeters to several tens of centimeters, is inserted into the auxiliary device 10, the main bar 21 is welded to the inner peripheral surface of the auxiliary device 10, the reinforcing bar cage 20 and the auxiliary device.
10 and 10 are fixed together.

Further, the rebar cage 20 is shown in FIGS. 1 (a) and 1 (b).
As shown in, the press-fitting pipe 30 is fixed. The press-fitting pipe 30 is formed of a metal pipe, a vinyl chloride pipe, or the like. For example, the tips of the four press-fitting pipes 30 are positioned at the middle of the internal height of the auxiliary device 10 and the inner surface of the rebar cage 20 is 90 degrees. Along each corner, it is fixed to the longitudinal main bar 21 or hoop bar 22 of the reinforcing bar cage 20 by binding with a wire or the like.

Incidentally, the auxiliary device 10, the press-fitting pipe 30, and the rebar cage 20
Can be individually supported without being integrated, but if they are integrated as in this example, the lifting work can be done once and the mutual alignment etc. is unnecessary,
Labor saving on site can be achieved. Although not shown, the press-fitting pipe 30 can also be used as the vertical main bar 21 of the reinforcing bar cage 20.

Now, as shown in FIG. 2, a pile hole H having a required radius and depth is excavated in the ground G, a slime treatment is applied to the bottom of the hole H, and a rooting mortar M is placed, and the auxiliary device 10 is used. The reinforced basket 20 to which the press-in pipe 30 and the press-fitting pipe 30 are fixed is hung in the pile hole H, the lower part of the auxiliary device 10 is solidified by its own weight and installed in the mortar M, and the tremie pipe T is used for concrete. Is cast in the pile hole H to form the cast-in-place pile 40.

When forming the cast-in-place pile 40, the slime treatment of the bottom of the pile hole H and the placement of the root-hardening mortar M are not always necessary and can be omitted depending on the situation. Also,
Although not necessarily required, it is preferable to apply a release agent or a resin coating or attach a thin film resin to the inner surface of the auxiliary device 10 in advance to facilitate the release from the concrete. When the pile 40 hardens after the required curing period, as shown in FIG. 3, a press-fitting pump P is connected to the upper end of the press-fitting pipe 30, and a hardening fluid 50 such as cement mortar is press-fitted, and the pressure is applied to the pile tip. Part, the concrete in the auxiliary device 10, is broken and cracked and divided into upper and lower parts, namely an upper part 41 and a lower part 42.

Then, the inner surface of the auxiliary device 10 is a cylinder,
Further, the lower part 42 of the divided pile tip portion acts as a piston, and the lower part 42 of the pile tip portion is lowered by the pressure of the fluid 50,
Consolidate the tip ground to increase bearing capacity. At the same time, the tip resistance of the pile 40 is estimated by the pressure input at that time. Further, the amount of press fit can also estimate the amount of subsidence of the lower portion 42 at the tip of the pile.
When it is confirmed that the tip resistance is equal to or larger than the designed resistance value, the press-fitting of the fluid 50 is stopped, and the curable fluid 50 that has been press-fitted is cured until it hardens.

When a plurality of press-fitting pipes 30 are used for press-fitting the curable fluid 50, as in the above embodiment, one or two pipes 30 are initially released and the remaining pipes are left open.
The fluid 50 is press-fitted with 30 and the outflow of the fluid 50 from the released pipe 30 is confirmed, and the opening / closing valve 60 of these pipes 30 is closed, or these pipes 30 are also connected to the press-fitting pump P,
It is preferable to press-in the curable fluid 50. That is, the air and muddy water in the pipe 30 are expelled from the released pipe 30 so that no cavity or the like is created in the tip of the pile.

Further, FIG. 4 shows a second part of the press-fitting pipe described above.
The embodiment shows an embodiment, and the press-fitting pipe 30 has a U-shaped tubular shape as a whole, and a plurality of discharge ports are provided in a horizontal portion 31 therebelow.
32 have been opened. And, although not shown, the press-fitting pipe
A press-fitting pump is connected to one end of the 30 protruding above the ground, and an opening / closing valve is provided at the other end. Thus, when the curable fluid 50 is press-fitted, the fluid 50 is
From one end of 30 to horizontal section 31 and low pressure pipe
Since it goes through the inside of 30 to the other end, surely press fit pipe
The air and muddy water in 30 can be expelled. After that, similar to the above description, the on-off valve may be closed to increase the pressure input of the fluid 50 and the desired work may be performed.

Although not shown, it is also possible to use a double pipe or the like for the press-fitting pipe 30. On the other hand, FIGS. 5 to 8 show a third embodiment of the present invention, and FIG. 5 (a) shows a partially cut-away vertical cross section showing a configuration of an auxiliary device and a rebar cage used in the method of the present invention. Fig., Fig. 6 (b) is the same plan view, Fig. 6 (a) is a partially cutaway vertical sectional view showing the structure of a press-fitting pipe and a partition plate, Fig. 6 (b) is the same plan view, and Fig. 7 is a pile. And FIG. 8 is an explanatory view showing the press-fitted state of the fluid.

In the description of this embodiment, the same components as those in the above-mentioned first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Auxiliary device 10 according to the third embodiment
As shown in FIGS. 5 (a) and 5 (b), is fixed to the lower end portion of the rebar cage 20 as in the case of the first embodiment described above, and the inner surface height thereof is midway, for example, middle or Locking protrusion 11 slightly above
... are projected several times.

Further, the press-fitting pipe 30 according to the third embodiment.
As shown in FIGS. 6 (a) and 6 (b), is independent of the rebar cage 20, and a partition plate 70 having a diameter smaller than the inner diameter of the auxiliary device 10 is attached to the lower end thereof. There is. As shown in FIGS. 6 and 7, the partition plate 70 is a donut-shaped metal plate having an opening 71 of a size that allows the tremie tube T to be sufficiently inserted therethrough. The tips of the four press-fitting pipes 30 are arranged at 90 ° intervals and are welded vertically to integrate them.

Further, the four press-fitting pipes 30 are held in shape by bundling several places in the height direction thereof with ring ribs 33 having substantially the same diameter as the partition plate 70. Now, as shown in FIG. 7, the rebar cage 20 to which the auxiliary device 10 is fixed is hung in a previously drilled pile hole H and installed at the bottom of the hole, and then four press-fitted pipes to which partition plates 70 are attached. The 30 is hung so as to be inserted into the auxiliary device 10, the partition plate 70 is locked and set on the locking projection 11 projecting on the inner surface of the auxiliary device 10, and then the tremie tube T is inserted. The cast-in pile 40 is formed by reaching the bottom of the hole through the opening 71 of the partition plate 70 and sequentially pouring concrete.

When the pile 40 hardens after the required curing period,
Similar to the above-described embodiment, the press-fitting pipe 30 is connected to the press-fitting pump P, and the hardening fluid 50 such as cement mortar is press-fitted as shown in FIG. The concrete is broken and cracked to be divided into upper and lower parts, that is, an upper part 41 and a lower part 42. In such a case, cracks occur along the partition plate 70, so that the cracks can be easily and horizontally divided. Subsequent post-processes are the same as those in the above-described first embodiment, and will be omitted.

Even in the third embodiment, the press-fitting pipe is used.
30 is fixed to the rebar cage 20 by means such as binding, or the rebar cage
It can also be used as the vertical main bar 21 of 20. In this way, it is preferable that the respective devices are integrated and the materials are also used in terms of cost and the number of steps to be reduced to save labor on site. However, if it is better to respond freely according to the situation of the construction site, on the contrary, these auxiliary devices 10, press-fitting pipes 30, rebar cages 20 and the like are individually set and used freely in combination. You can also do it. Further, as described above, the partition plate 70 may be one that acts as a starting point of a crack when the pile tip portion in the auxiliary device 10 is vertically divided by the curable fluid 50 pressure, and therefore, As in this example, it does not necessarily have to be in a donut shape, and may be formed in a knitted shape or a childlike shape of a cage, or may be a plate shape without openings.

[0037]

Since the present invention is constituted as described above, it has the following effects. Claim 1
According to the method described in any one of 5 to 5, it is possible to inexpensively confirm the supporting force of the cast-in-place pile and increase the supporting force of the tip ground with a simple device that also serves as the cylindrical auxiliary device, the press-fitting pipe, and preferably the partition plate. There is an effect that can be.

Therefore, when high reliability is required,
By applying the method of the present invention to all or most of the piles constructed on site, the performance of each pile can be guaranteed. It is also possible to review the current cast-in-place piles that tend to be over-designed and design an appropriate cast-in-place pile to provide a high-quality and inexpensive foundation pile. That is, according to the method of claim 1, by simply installing a simple and inexpensive device in the pile hole before forming the cast-in-place pile, after the pile is hardened, the support force can be easily confirmed and the tip support force can be increased. Can be achieved.

According to the method described in claim 2, in addition to the effect of the method described in claim 1, in particular, when the tip of the pile is broken up and down by the pressure of the fluid in the cylindrical auxiliary device, The tip of the pile can be divided easily and horizontally. According to the method of claim 3, by fixing the auxiliary device to the lower end portion of the reinforcing bar cage in advance by means such as welding, the auxiliary device and the reinforcing bar cage can be installed in the pile hole at the same time. Therefore, the labor and the number of steps can be reduced.

According to the method of the fourth aspect, the press-fitting pipe can be provided at a low cost particularly by using the press-fitting pipe as a part or the whole of the main bar of the reinforcing bar cage. According to the method of claim 5, by providing the partition plate with an opening that communicates with the top and bottom, concrete can be poured through the opening below the partition plate when the concrete is poured.
Therefore, it is possible to prevent a cavity or the like from being formed below the partition plate.

[Brief description of drawings]

FIG. 1 (a) is a partially cutaway vertical sectional view showing the configuration of an auxiliary device, a press-fitting pipe, and a rebar cage according to the first embodiment of the present invention, and FIG. 1 (b) is a plan view thereof. is there.

FIG. 2 is an explanatory view showing construction of a pile according to the first embodiment.

FIG. 3 is an explanatory diagram showing a press-fitted state of a fluid according to the first embodiment.

FIG. 4 is an enlarged vertical cross-sectional view of a main part showing a press-fitting pipe according to a second embodiment of the present invention.

FIG. 5 (a) is a partially cutaway vertical sectional view showing a configuration of an auxiliary device and a reinforcing bar cage according to a third embodiment of the present invention.
(b) is a plan view of the same.

FIG. 6 (a) is a partially cutaway vertical sectional view showing the configuration of a press-fitting pipe and a partition plate according to the third embodiment, and FIG. 6 (b) is a plan view thereof.

FIG. 7 is an explanatory diagram showing construction of a pile according to a third embodiment.

FIG. 8 is an explanatory diagram showing a press-fitted state of a fluid according to the third embodiment.

[Explanation of symbols]

 G Ground H Pile hole M Root consolidation mortar T Tremy pipe P Press-fitting pump 10 Auxiliary device 11 Locking protrusion 20 Reinforcing bar basket 21 Vertical main bar 22 Hoop muscle 30 Press-fitting pipe 31 Horizontal part 32 Discharge port 33 Ring bar 40 Pile 41 Pile tip part Upper 42 Lower part of pile tip 50 Fluid 60 Open / close valve 70 Partition plate 71 Open

Claims (5)

[Claims] 1. A tubular auxiliary device having substantially the same diameter as the pile hole is installed at the bottom of the pile hole, and the lower end of the press-fitting pipe is positioned halfway inside the auxiliary device, and concrete is placed in the pile hole. After the pile is hardened, the hardenable fluid is press-fitted through the press-fitting pipe at the required pressure, and the force input causes the tip of the pile in the auxiliary device to be split up and down to reduce the friction of the peripheral surface of the pile. A method for confirming and increasing the bearing capacity of a cast-in-place pile, characterized by consolidating the tip ground as a reaction force to increase the bearing capacity and confirming the bearing capacity by the fluid pressure input. 2. A tubular auxiliary device having a diameter substantially the same as that of the pile hole is installed at the bottom of the pile hole, and a press-fitting pipe having a partition plate having a diameter smaller than the inner diameter of the auxiliary device is attached to the lower end portion of the auxiliary device. Situated midway, concrete is placed in the pile hole to create a pile, and after hardening the pile, a hardenable fluid is pressed in at a required pressure through the press-fitting pipe, and the press-in force assists the tip of the pile. It is characterized in that it is divided up and down at the partition plate position in the device, the tip ground is consolidated by using the peripheral friction of the pile as a reaction force to increase the supporting force, and the supporting force is confirmed by the fluid pressure input. How to check and increase bearing capacity of cast-in-place piles. 3. The method for confirming and increasing the support force of a cast-in-place pile according to claim 1 or 2, wherein the auxiliary device is fixed to the lower end portion of the rebar cage. 4. The method for confirming and increasing the bearing capacity of a cast-in-place pile according to claim 1, wherein the press-fitting pipe also serves as the main bar of the reinforcing bar cage. 5. The method for confirming and increasing the supporting force of a cast-in-place pile according to claim 2, wherein the partition plate has an opening that communicates vertically.