JPH0557370B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is characterized in that the roots made of concrete reinforced with reinforcing bars extend from the peripheral surface of the pile like the roots of a tree, thereby increasing the pile bearing capacity. Alternatively, the present invention relates to a pile device that is expected to significantly improve pile pull-out resistance.

(Prior Art and Problems 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 underground layer, 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 with no solid strata below, the bearing capacity of the pile driven into the ground is
This is mainly achieved by the frictional force generated between the soil and the surrounding surface of the pile, but when relying on the supporting force due to such frictional force, it is necessary to line up a large number of piles to prevent excessive settlement over a long period of time. There was a problem similar to that of the support pile mentioned above.

In addition, as a type of pile that tries to obtain pile-supporting capacity through frictional force, there is also a flanged pile, which has a flange protruding around the pile to improve its bearing capacity. In order to avoid problems, the amount of protrusion of the flanges has to be relatively small, and therefore there is a certain limit to the improvement of the pile supporting capacity by flanged piles.

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, the pile device 1 according to the present invention employs the following configuration.

That is, in the pile device 1 of the present invention, a through hole 3 is bored at an appropriate location on the circumferential surface of a pile base body 2 having an open upper end and a hollow portion 7 continuous in the length direction. The part 16 is formed into a tapered shape and is closed from the outside by a cap member 6 which can be pushed into the ground layer by the pressure of the filling concrete filled into the hollow part 7 with pressure. , an appropriate number of reinforcing bars 5 each having an engaging portion 23 at its tip that can protrude into the hollow portion 7 and engage with the inner peripheral edge 22 of the through hole 3 when the cap member 6 closes the through hole 3; is fixed at its proximal end portion 25 (a reinforcing bar having no engaging portion may also be fixed).

In addition, when the pile device 1 of the present invention is used for the purpose of improving the pile supporting capacity, the through hole 3 is
It is preferable to drill the pile so that the root portion 29 (to be described later) is directed downward and is inclined outwardly and downwardly, and the pile device 1 of the present invention is used for the purpose of improving pile pull-out resistance. If this is the case, it is preferable to make the holes so as to be inclined outwardly and upwardly so that the root-like portions 29 are formed upwardly.

(Function) When the hollow portion 7 is filled with concrete 30 under pressure while the pile base 2, in which the through hole 3 is closed by the cap member 6, is sunk in the ground layer 27 as required, the cap member 6 Under the pressure of the filled concrete, the cap member 6 is pushed diagonally downward into the ground layer 27, but at that time, the cap member 6 is pushed into the ground layer 27 with the reinforcing bar 5 guided by the peripheral surface 13 of the through hole 3. The cap member 6 enters the ground layer 27 and stops when the engaging portion 23 at the tip of the reinforcing bar 5 engages with the inner peripheral edge 22 of the through hole 3. Then, the hole formed by the penetration of the cap member 6 is filled with concrete. The root portion 29 made of concrete reinforced with reinforcing bars thus formed is formed as if a root of a tree extends from the through hole 3 portion of the sunken pile peripheral surface. The root-like part 29
The length varies depending on the condition of the ground layer in which the pile base 2 is deposited, the diameter of the pile base 2, etc., and may be, for example, about 30 cm. In addition, in the above, "sinking the pile base into the ground layer" means burying the pile base in a hole drilled in the ground layer with an earth drill and sinking it, as well as sinking the pile base by driving the pile base into the ground layer. It means to do. The technical meaning of "sinking" is the same below.

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

1 to 6, the pile device 1 of the present invention is constructed by attaching a cap member 6 provided with reinforcing bars 5 to a through hole 3 provided at an appropriate location on the circumferential surface of a pile base 2.

The pile base 2 is formed, for example, as a concrete pile having a hollow part 7 that is open at the top and continuous in the length direction, and has a step 10 in a large-diameter outer circular hole 9 on the peripheral surface part 8. A stepped through hole 3a formed by connecting small-diameter inner circular holes 11 is bored outwardly and downwardly inclined. Note that the direction of inclination is preferably set to 45 degrees, for example.
In addition, the drilled portion of the through-hole 3 is, for example, if the through-hole 3 is in a state where it does not intersect with the reinforcing bars 5 fixed to each cap member 6 when the through-hole 3 is closed with the cap member 6. This is optional as shown in FIG. In addition, when the length of the reinforcing bars 5 is long, the through holes 3 in the circumferential direction are set in a staggered manner, as shown in FIG. 1, for example.

The cap member 6 has a cylindrical body 15 that is inserted through the through hole 3 so as to be in close contact with the circumferential surface of the inner circular hole 11.
A conical head 20 whose distal end portion 16 has a tapered shape and whose peripheral edge portion 19 of the proximal end surface portion 17 can come into contact with the step 10 is continuously provided at the central portion of the proximal end surface portion 17, For example, the entire structure is manufactured as a single piece of casting. The cap member 6 opens the through hole 3 in a state in which the peripheral edge portion 19 of the proximal end surface portion 17 of the conical head portion 20 is in contact with the step 10.
(see Fig. 1) to prevent soil from entering the hollow part 7 from the through hole 3 when the pile base 2 is sunk into the ground layer. Note that in this example, the through hole 3
The reason why the hole 3a is formed as a stepped through hole 3a is so that the head 20 of the cap member 6 can be accommodated in the outer circular hole 9, so that the pile can be more smoothly set down. Further, the inner circumferential surface 21 of the cylindrical body 15 of the cap member 6 has a structure that can protrude into the hollow portion 7 and engage with the inner circumferential edge 22 of the through hole 3 when the cap member 6 closes the through hole 3 ( For example, an appropriate number of reinforcing bars 5 each having an engaging part 23 as a hook part at the tip are welded or screwed together at the proximal end part 25 so as to form an annular shape. It is fixed by means. In order to close the through hole 3 from the outside using the cap member 6 equipped with the reinforcing bars 5, the entire reinforcing bars 5 are made in a narrowed state so that the engaging portion 23 does not come into contact with the through hole 3. The tips of the reinforcing bars 5 in the narrowed state are positioned in the hollow part 7 through the through hole 3, and the head 20 of the cap member 6 is housed in the outer circular hole 9. If there is a risk that the cap member 6 will come off the through hole 3 during the sinking of the pile, for example, as shown by the dashed line in FIG. The cap member 6 may be fixed to the outer peripheral portion of the proximal end of the cylindrical body 15, as shown in FIG. .

The pile device 1 having such a configuration is installed in the ground layer 27.
In order to form the root part 29 in a state where the root of a tree extends from the perforated part of the pile peripheral surface part 8, after the pile device 1 is deposited in the ground layer 27,
The hollow portion 7 is filled with concrete 30 under pressure. To illustrate the concrete filling method, first, the hollow portion 7 of the pile base 2 is filled with concrete. Thereafter, as shown in FIG. 7, for example, the cylinder 36 is placed on the pile base 2 while ensuring the close contact of the joint 33 so that the cylinder opening 31 is in communication with the upper end 32 of the hollow part of the pile base 2. The pile base 2 and the cylinder 36 are integrated by a fixing member 35. After that, a required amount of concrete 30 is poured into the cylinder 36 from the injection port until the required height of the cylinder 36 is reached.
The concrete 30 in 6 is pressed by a piston 39 driven by a hydraulic cylinder 37.
Due to this pressing, the cap member 6 including the conical head 20 receives the pressure of the filling concrete and forms a hole corresponding to the diameter of the base end of the head 20 in the direction of inclination of the through hole 3. The reinforcing bars 5 penetrate into the ground layer 27, thereby forming roots 29 in which the reinforcing bars 5 are wrapped with concrete of a required thickness. If the roots are formed with the roots facing downward, there is a risk that the pile base 2 will float up due to the reaction caused by the penetration of the cap member in each through hole when the piston 39 presses. The piston 39 is preferably pressed while pressing the pile base 2 downward using the weight of a pile driver, for example. Also, the number of times concrete is poured into the cylinder 36, and therefore the number of times the piston 39 is pressed, is such that a sufficient amount of concrete is poured into each through hole 30 to form a root-shaped portion 29 of a required length in each through hole 3 portion. It is set up so that it can be supplied. As shown in FIG. 7, the fixing tool 33 fixes a locking ring 41 having a V-shaped groove 40 to the upper end portion of the pile P, and also has a connection that can engage with the V-shaped groove 40 at the tip. The upper end of the rod 42 can be fixed to the outer peripheral surface 43 of the cylinder 36 using a bolt 45, and the connecting rod 42 is fixed to the cylinder 36 with the bolt while the tip is engaged with the V-shaped groove 40. The joint portion 35 with the base body 2 can be closely integrated with the base body 2.

FIG. 8 shows a case in which the pile base 2 is formed as a steel pile, and a state in which the proximal peripheral edge portion 19 of the head 20 of the cap member 6 is partially in contact with the outer peripheral edge of the through-hole of the pile base 2. A cylindrical body 15 connected to the head 20 closes the through hole 3. The action of the pile device 1 having such a configuration is the same as in the case of the above embodiment, but when the pile base 2 is made of steel in this way, corrosion of the pile base 2 is difficult to avoid. As shown in part in the figure, after each cap member 6 is pushed into the ground layer 27,
While the filling concrete is still soft, vertically long reinforcing bars 46 woven into a circular cylindrical shape, for example, are placed in the hollow part 7 of the pile base 2 over the entire length of the hollow part 7, and the reinforcement is reinforced by the reinforcing bars 46. It is preferable to form a concrete pile portion 47 with a solid shape.

(Effects of the Invention) The pile device of the present invention has a configuration in which a cap member provided with reinforcing bars is attached to a through hole provided at an appropriate location on the circumferential surface of a pile base having a hollow portion. It is possible to expect a significant improvement in resistance, reduce construction costs and improve work efficiency, and furthermore, it can be manufactured at a relatively low cost with a simple structure.

This will be specifically explained below in accordance with the order of operation of the pile device of the present invention.

After the pile is sunk as required with the through hole closed by the cap member (when sinking the pile, the cap member in the closed state reliably prevents soil from entering the hollow part from the through hole). ), when the hollow part is filled with concrete under pressure, the reinforcing bars of the cap member are guided to the periphery of the hole by the concrete pressure applied to the cap member, and the cap member is naturally pushed into the ground layer as required.

Since the cap member can be pushed in easily in this way without requiring a special actuating device or energy source, the pile device according to the present invention can be provided at a relatively low cost with a simple structure. It is.

The hole formed by the intrusion of the cap member will be reinforced with reinforcing bars and filled with concrete, so tree roots will be able to seep through the hole drilled on the surrounding surface of the sunken pile. The root-like part is formed in an elongated manner, and even when the lower end of the sunken pile does not reach a solid stratum, it exerts an extremely large bearing capacity.
Therefore, unlike conventional piles, many piles must be successively deposited until they reach a solid stratum, or a large number of friction piles must be sunk in groups (friction piles are often used as flanged piles). Even if it were adopted, there was a limit to the improvement of the bearing capacity by flanges, so the inconvenience of having to sink several piles with flanges was eliminated, reducing construction costs and improving work. It is possible to improve efficiency.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing an embodiment of a pile device according to the present invention constructed with a concrete pile base; FIG. 2 is a perspective view showing a cap member with reinforcing bars attached to the pile base; Fig. 3 is a cross-sectional view showing a root-shaped portion formed by a cap member with reinforcing bars, Fig. 4 is a cross-sectional view illustrating a manner of drilling a through hole in a pile base, and Fig. 5 is a locking band. Figure 6 is a cross-sectional view showing the root-like part extending from the peripheral surface of the pile like a tree root, and Figure 7 is a concrete filling device that fills the hollow part of the pile base with concrete using pressure. 8 is a partial sectional view showing another embodiment of the present invention constructed with a steel pile base, and FIG. 9 is a sectional view showing a reinforced concrete portion formed in the pile device according to FIG. 8. It is a diagram. 1...Pile device, 2...Pile base, 3...Through hole, 5
... Reinforcement bar, 6 ... Cap member, 7 ... Hollow part, 23 ... Engagement part.

Claims (1)

[Claims] 1 A through hole 3 is bored at an appropriate position on the circumference of the pile base 2 which has an open upper end and a hollow portion 7 continuous in the length direction, and the through hole 3 has a tip 16 formed in a tapered shape and The hollow part 7 is closed from the outside by a cap member 6 which can be pushed into the ground layer by the pressure of the filling concrete filled with pressure into the hollow part 7. An appropriate number of reinforcing bars 5 each having an engaging part 23 at the tip thereof that protrudes into the hollow part 7 and can engage with the inner circumferential edge 22 of the through hole 3 when the lid is closed is fixed at the proximal end part 25 thereof. A pile device characterized by: