JPH0280711A - Pipe device for forming board-like bearing member around bottom and its usage - Google Patents

Abstract

PURPOSE:To greatly increase bearing capacity of a pile even in soft ground by making a bottom member provided at the lower opening of a pile base body descend to a certain extent, and by making concrete grouted therein protrude to form a bearing member. CONSTITUTION:A pile base body 2, with its upper and lower ends opened and having a hollow part 6, is planted deep into the ground G with its lower end opening 3 blocked up with a bottom member 5. Then the hollow part 6 is filled with concrete C that is grouted, and the bottom member 5 then gradually descend being guided by a guide member 9 with pressure applied by the grouting. When the descend reaches its maximum as previously fixed, the concrete C at the inside of the hollow part 6 protrudes. As the downward flow of the concrete is deterred by the bottom member 5, the concrete moves toward the lateral sides of the lower end opening 3 of the pile base body 2 and forms a concrete bearing member 28 extending radially around the opening.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to forming a concrete plate-shaped supporting part extending outward from the pile at its lower end. The present invention relates to a pile device which is expected to significantly improve pile supporting capacity by means of a support portion, and a method of using the same.

(Prior art and problem to be solved by the invention) When the ground is soft and difficult to support the structure above, the load of the structure is transferred to the hard stratum through support piles that penetrate the soft stratum and reach the hard stratum. This construction method is generally adopted. In this construction method, the maximum length of each support pile is about 15 m, so if there is a deep layer of solid soil, it is necessary to connect several support piles one after another and sink them into the ground layer. In addition to the problem of increasing the construction cost of the support pile foundation, there was also the problem of poor work efficiency.

In addition, in the case of soft ground where there is no solid stratum below, the supporting force of the pile driven into the ground is mainly obtained from the frictional force generated between the soil and the surrounding surface of the pile. However, when considering the bearing capacity due to such frictional force, it was necessary to lay a large number of piles side by side to prevent excessive settlement over a long period of time, which caused the same problem as with the support piles mentioned above. .

An object of the present invention is to provide a pile device that can solve these problems.

(Means for Solving the Problems) In order to achieve the above object, a pile device according to the present invention has the following configuration.

That is, the pile device 1 according to the present invention includes a pile base 2 having a hollow portion 6 that is open at the upper and lower ends and continuous in the length direction, and the hollow portion 6 is filled with concrete.
The lower end opening 3 can be closed by the bottom member 5, and the bottom member 5 in the state where the lower end opening 3 is closed has a hollow portion 6 after the pile base 2 is deposited in the ground layer as required.
The pile base 2 is characterized by being guided by a guide portion 7 provided at the lower end of the pile base 2 and lowered by a required amount by filling the concrete with inward pressure.

In the pile device according to the present invention, the bottom member 5 is formed as a cone that becomes thinner toward the bottom, and the guide shaft 15 is implanted at approximately the center of the upper surface of the bottom member 5, while the lower end of the hollow portion 6 It is preferable that the pile base 2 supports a guide portion 9 as a guide pipe 9a that extends in the direction of the central axis of the pile base 2 and into which the guide shaft 15 can be inserted.

Further, in the pile device according to the present invention, the bottom member 5 is formed as a cone that becomes narrower toward the bottom, and a plurality of guide shafts 36 are planted at a required interval on the peripheral edge of the upper surface of the bottom member 5. On the other hand, at the lower end portion of the hollow portion 6, a guide portion 9 serving as a guide pipe 9b extending in the length direction of the pile base 2 and into which the guide shaft 36 can be inserted is provided in the hollow portion 6 in correspondence with each guide shaft. It is preferable to fix it to the inner circumferential surface portion 37 of.

The method of using the pile device according to the present invention is to deposit the pile device according to claim (1) in the ground layer as required in a state where the bottom member 5 closes the lower end opening 3 of the pile base 2. Concrete C is filled with pressure into the hollow part 6 from the upper end opening of 2, and the bottom member 5 is lowered by the pressure of the filled concrete C while being guided by the guide part 9, and by this lowering, the pile base 2 is The lower end opening 3 is left open over its entire periphery or substantially over its entire periphery, and concrete is forced outward from the open area into the ground layer.

(Function) When the pile base 2 is sunk into the ground layer G as required with the lower end opening 3 of the pile base 2 closed by the bottom member 5, and then the hollow part 6 is filled with concrete C under pressure, The bottom member 5 receives the pressure of the filled concrete and is guided by the guide portion 9 and gradually moves downward away from the lower end opening 3 of the pile base 2. After the bottom member 5 has descended by a preset amount, the concrete pushed out from the lower end opening 3 of the pile base 2 is prevented from moving downward by the bottom member 5. The pile base 2 is pushed outward from the opening formed between the lower end opening 3 and the bottom member 5, and as shown in FIG. A concrete support portion 28 is formed in a state that extends around the portion.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 to 4, a pile device 1 according to the present invention has a pile base 2
The lower end opening 3 can be closed by the bottom member 5.

The pile base 2 is formed as a cylindrical body made of concrete, for example, with a hollow part 6 that is open at the upper and lower ends and continuous in the length direction, and an annular member 7 is fixed to the lower end and the hollow part 6 A guide portion 9 is provided at the lower end portion of the portion 6. The guide portion 9 is formed as a guide pipe 9a extending in the direction of the central axis of the hollow portion 6, and the guide pipe 9a is connected to a plurality of plate-shaped support members 1) fixed to the annular member 7 of the pile base 2. Supported by

As shown in FIG. 1, for example, the bottom member 5 is formed as a conical concrete block that tapers downward and has an outer diameter of the upper end surface 12 equal to the outer diameter of the pile base 2; A guide shaft 15 having a threaded shaft portion 13 inserted into the guide pipe 9a is implanted in the center portion of the guide pipe 12. Note that the reference numeral 14 shown in FIGS. 1 to 4 is a reinforcing reinforcing bar provided so as to protrude into the hollow portion 6 at a peripheral portion of the upper surface of the bottom member 5.

The bottom member 5 having such a configuration has its guide shaft 15
is inserted into the guide pipe 9a, and the guide pipe 9
An engagement nut member 17 that can be engaged with the upper end 16 is provided at the upper end portion of the guide shaft 15 that projects upward from the upper end 16 of a.
are screwed together. However, the bottom member 5 closes the lower end opening 3 of the pile base 2 when its upper end surface 12 comes into contact with the lower end surface 18 of the pile base 2, and the retaining NAND member 17
can be lowered until it engages with the upper end 16 of the guide pipe 9a. The amount of subsidence is set to about 15 cm, for example. Note that the bottom member 5 is kept in a state in which the lower end opening 3 of the pile base 2 is closed until the pile base 2 is sunk into the ground layer G as required, for example by using an adhesive tape 19 (see FIG. 3). be held.

In order to form a concrete plate support part at the lower end of a submerged pile using a pile device having such a configuration, the lower end opening 3 of the pile base 2 is closed by the bottom member 5. 2 is deposited in the ground layer G as required, and then the hollow part 6 is filled with concrete C. Thereafter, the cylinder opening 20 is inserted into the upper end of the pile base 2 at the hollow upper end 21 of the pile base 2.
The cylinder 23 is mounted while ensuring the close contact of the joint 22 so as to be in communication with the pile base 2 and the cylinder 23 using a fixture 25, which will be described later.

After that, a required amount of concrete is injected into the cylinder 23 from its injection port 26, and the concrete in the cylinder 23 is poured into the cylinder 23 by a piston 29 driven by a hydraulic cylinder 27.
Press by. Due to this pressing, the bottom member 5 receives the pressure of the filling concrete (the adhesive tape 19 integrates the bottom member 5 with the pile base 2 until the bottom member 5 receives the pressure of the filling concrete). The guide pipe 9a gradually descends while pressing the soil at its tip until the engaging nut member 17 engages with the upper end 16 of the guide pipe 9a (see FIGS. 2 and 4). After the bottom member 5 sinks by a predetermined amount, the concrete C extruded from the open lower end of the pile base 2 is prevented from moving downward by the bottom member 5, so that it subsequently moves laterally. trying to expand. In this example, since the lower end opening of the pile base 2 formed by lowering the bottom member 5 is open all around, the concrete C extruded from the hollow part 6 is 2 in the radial direction of the pile base 2, thereby forming a concrete plate-shaped support portion 28 at the lower end of the pile base 2. The extent to which this support portion 28 is required to spread in the lateral direction is set in advance according to the geology of the ground and the required pile support capacity, and a support portion of a desired size is formed. Therefore, the pressure of the hydraulic cylinder 27 and the number of injections of concrete into the cylinder 23 (i.e., the piston 29
(number of presses) to the required value.

As shown in FIG. 5, for example, the fixture 25 fixes a locking ring 31 having a V-shaped groove 30 to the upper end portion of the pile base 2, and has a connecting rod that can engage with the V-shaped groove 30 at its tip. The upper end of the connecting rod 32 can be fixed to the outer circumferential surface 33 of the cylinder 23 using a bolt 35, and the connecting rod 32 is fixed to the cylinder 23 with the bolt while the tip is engaged with the V-shaped groove 30, so that the cylinder 23 and the pile base are fixed. Joint part 2 with 2
2 can be closely integrated.

In the pile device 1 according to the present invention, means for guiding the bottom member 5 to the guide portion 9 provided at the lower end of the pile base 2 include, for example, in addition to those shown in the above embodiments. Examples include those shown in FIGS. 6 and 7. That is, this means forms the bottom member 5 as a cone (for example, a cone) that becomes thinner toward the bottom, and implants a plurality of guide shafts 36 at a predetermined interval on the upper peripheral edge of the bottom member 5. On the other hand, at the lower end portion of the hollow portion 6, the pile base 2
A guide portion 9 serving as a guide pipe 9b extending in the length direction and into which the guide shaft 36 can be inserted is fixed to the inner circumferential surface portion 37 of the hollow portion 6 in correspondence with each guide shaft. As in the case of the previous embodiment, the upper threaded shaft portion 3 of the guide shaft 36 through which the guide pipe 9b is inserted
By screwing the engagement nut member 40 into the bottom member 9, the bottom member 5 can be lowered until the engagement nut member 40 engages with the upper end 41 of the guide pipe 9b (see FIG. 7).

The form of the bottom member 5 may be such that the bottom member 5 is lowered by filling concrete with pressure into the hollow part, thereby opening the lower end opening 3 of the pile base 2. can be set arbitrarily.

(Effects of the Invention) Since the present invention is configured as described above, the bottom member can be lowered as required by filling concrete with pressure into the pile base after it has been deposited in the ground layer as required. This allows the lower end of the pile base to
It is possible to form a concrete plate-shaped supporting part that extends laterally at the lower end of the pile base, and it is possible to expect a significant improvement in the pile supporting capacity based on the resistance force generated by the plate-shaped supporting part. Therefore, compared to the conventional method of connecting a number of piles one after another and sinking them into the ground layer, or laying a large number of piles side by side, it is possible to reduce construction costs and improve work efficiency.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing the pile device according to the present invention, Figs. 2 and 3 are sectional views explaining its operation, and Fig. 4 is a concrete plate-shaped support formed at the lower end of the pile. FIG. 5 is a cross-sectional view showing a concrete filling device for filling concrete into the hollow portion of a pile base with pressure, and FIG. 6 is a partially cutaway view showing another embodiment of the pile device according to the present invention. The cut perspective view and FIG. 7 are cross-sectional views for explaining the function. DESCRIPTION OF SYMBOLS 1... Pile device, 2... Pile base, 3... Lower end part 0 part of pile base, 5... Bottom member, 6... Hollow part, 9...
Guide part, 15.36...Guide shaft.

Claims (4)

[Claims] (1) Hollow part 6 that is open at the top and bottom ends and continuous in the length direction
The bottom opening 3 of the pile base 2, which has a hollow part 6 filled with concrete, can be closed by the bottom member 5, and the bottom opening 3 is closed. 5, after the pile base 2 has been sunk to the required level in the ground layer, the hollow part 6 is filled with concrete using pressure, and the pile base 2 is guided by the guide part 9 provided at the lower end of the pile base 2 and lowered by the required amount. A pile device characterized by being made to be able to. (2) The bottom member 5 is formed as a cone that becomes thinner toward the bottom, and the guide shaft 15 is implanted at approximately the center of the upper surface of the bottom member 5, while the pile base is installed at the lower end of the hollow portion 6. 2. The pile device according to claim 1, wherein the pile base body 2 supports a guide portion 9 serving as a guide pipe 9a extending in the central axis direction of the pile base body 2 and into which the guide shaft 15 can be inserted. (3) The bottom member 5 is formed as a cone that becomes narrower toward the bottom, and a plurality of guide shafts 36 are implanted at required intervals on the peripheral edge of the upper surface of the bottom member 5,
A guide pipe 9 that extends in the length direction of the pile base 2 and into which the guide shaft 36 can be inserted at the lower end portion of the hollow portion 6
Claim (1) wherein the guide portion 9 as b is fixed to the inner circumferential surface portion 37 of the hollow portion 6 in correspondence with each guide shaft.
Pile device as described. (4) After the pile device according to claim (1) is sunk in the ground layer as required with the bottom member 5 closing the lower end opening 3 of the pile base 2, the hollow portion is opened from the upper end opening of the pile base 2. 6 is filled with concrete C under pressure, and by the pressure of the filled concrete C, the bottom member 5 is lowered while being guided by the guide part 9, and by the lowering, the lower end opening 3 of the pile base 2 is opened all around the bottom member 5. 1. A method for using a pile device, characterized in that the entire area or substantially the entire periphery of the pile device is left open, and concrete is pushed outward from the open portion into the ground layer.