JPH0291317A - Pile driving method - Google Patents

Abstract

PURPOSE:To prevent impossibility of driving a pile and unexpected breakages as well as ensure sealing at the tip of a soil pressing tool to intend more smooth and efficient construction by having the balloon-like soil pressing tool provided in a steel-pipe pile so as to permit relief action on excessive press-down reaction. CONSTITUTION:A soil pressing tool 2, which comprises a balloon-like structure 5 to effect press-down action on sediment 3a entering into a steel-pipe pile 1 as it is driven and to perform relief action upward inside the pile by means of press-down reaction N when it is at a set value or more, is provided in the pile. As pile driving is kept on, the soil pressing tool 2 is put into press-down action on the sediment 3a while being involved in relief action upward at every time when the reaction N from the sediment 3a exceeds a set value. Also, in the set value or less of the reaction N, pressurized fluid is supplied to the balloon-like structure 5 via a hose 4, expanded and pressed in contact with the inner periphery of the pile, so that the soil pressing tool 2 is kept in position inside the steel-pipe pile 1 against the reaction N.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a pile driving method.

[Conventional technology]

Conventionally, when driving cylindrical piles such as steel pipe piles, in order to increase the end-blocking effect and obtain a large end-bearing capacity, a hole was placed inside the pile end as shown in Figures 4 (A) and (Ill). The cylindrical pile (1) was driven in with the ribs (7) as shown in FIG.

[Problem to be solved by the invention]

However, in the above-mentioned conventional construction method, the effect of the ribs to hold down the soil that has entered the pile is insufficient, and the expected end-closing effect cannot be obtained sufficiently, or conversely, the reaction force acting on the ribs to hold down the earth and sand becomes excessive. This sometimes made it impossible to drive the cylindrical piles or caused unexpected damage.

The object of the invention is to solve the above-mentioned problems.

[Means to solve the problem]

The characteristic configuration of the pile driving method according to the present invention is that inside the cylindrical pile, a portion near the pile tip acts to suppress earth and sand that enters the pile as the cylindrical pile is driven into the ground, and also acts to counteract the pressing action. The purpose of driving the cylindrical pile is to perform the driving work of the above-mentioned cylindrical pile with the earth-pushing tool attached, which moves upward inside the pile due to the reaction force when the force exceeds the set value. That's right.

[For production]

In other words, when the pressing reaction force from the soil entering the pile exceeds the set value, the earth pushing tool escapes upward inside the pile due to the pressing reaction force, so the pressing reaction force does not become larger than necessary. Thereby, it is possible to prevent the inability to drive piles and unexpected damage during construction due to excessive pressing reaction force.

In addition, since it is possible to reliably prevent the push-down reaction force from increasing in this way, the pushing area of the earth pushing tool against the earth and sand that has entered into the pile is made sufficiently large with a margin, and the earth pressing tool can be used against the earth and sand that has entered into the pile. can be reliably pressed until the pressing reaction force reaches a set value, and thereby the desired tip closing effect can be reliably obtained.

〔Effect of the invention〕

As a result of the above, it has become possible to prevent pile driving failure and unexpected damage during construction, making it possible to perform pile driving work more stably and efficiently than before, and to achieve the desired tip closure effect. By reliably obtaining this, it is possible to ensure that the driven pile has a large tip bearing capacity, and the reliability of pile driving construction in terms of construction quality can be greatly improved compared to the conventional method.

〔Example〕

Next, an example will be described.

Figures 1 (a), (b), and (c) show the process of driving a steel pipe pile (1) (an example of a cylindrical pile), and (2) in the figure shows the steel pipe pile (1) in the ground (3). ) is pressed against the soil (3a) that has entered the pile, and when the pressing reaction force (N) exceeds the set value, the pressing reaction force (N
) is an earth-pushing tool that escapes upward inside the pile, and as shown in Figure 1 (a), the earth-pushing tool (2) is connected to the steel pipe pile (1
), and as the pile driving work progresses, as shown in the order of (a), (b), and (viii) in Figure 1, Each time the pressing reaction force (N) from the soil entering the pile (3a) exceeds the set value, the earth pushing tool (2) is moved upward to release the soil pushing tool (2) from the soil entering the pile (3a). By applying pressure to the pile, it is possible to prevent the pile from being unable to drive during construction or from unexpected damage due to excessive pressure reaction force (N) from the soil (3a) that has entered the pile. A blocking effect is reliably obtained, and the driven steel pipe pile (1) is provided with a large tip supporting force.

As shown in Figures 2 and 3, the earth pushing tool (2) is used to pressurize the inside of the steel pipe pile (1) by supplying pressurized fluid from the connection hose (4) passed through the inside of the steel pipe pile (1). expands with
The expansion force (P) presses against the inner peripheral surface of the pile, and the steel pipe pile (1) maintains its position against the pressing reaction force (N) that is less than the set value and is received from the soil (3a) that has entered the pile. , a balloon-shaped body (5) that slides upward inside the pile is used when the holding reaction force (N) exceeds a set value, and a connecting hose (
Adjust the pressurized fluid supply pressure from 4) to create a balloon-shaped body (5).
By adjusting the pressing force against the inner circumferential surface of the pile, the set value of the pressing reaction force (N) that causes the earth pressing tool (2) to escape can be changed and adjusted as appropriate depending on the soil quality and the like.

In addition, after completing driving the steel pipe pile (1), a balloon-shaped body (5
) is released from the connection hose (4) and the balloon-shaped body (5) is deflated, and the balloon-shaped body (5) as the earth pushing tool (2) is placed on the driving steel pipe pile (1). Remove it from inside and collect it.

(6) is an inner shell tube as a core material of the balloon-shaped body (5).

The fluid to be pressurized and supplied to the balloon-shaped body (5) may be gas,
Various fluids can be applied regardless of liquid.

Furthermore, various types of devices can be used for supplying pressurized fluid to the balloon-shaped body (5) via the connecting hose (4).

[Another example]

Next, another embodiment will be described.

The target tubular piles are not limited to steel pipe piles,
The pile material does not matter.

In addition, the concrete structure of the earth pressing tool (2) that causes the inside of the pile to escape upward when the pressing reaction force (N) exceeds a set value,
The shape can be modified in various ways and is not limited to the balloon structure as shown in the above embodiments.

Note that although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structures and methods shown in the accompanying drawings.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, and FIG. 1 (
A), (0), and (C) are diagrams showing the pile driving process, Figure 2 is an enlarged sectional view, and Figure 3 is a sectional view taken along the line ■-■ in Figure 2. Figures 4(A) and 4(0) are a side view and a bottom view showing a conventional example. (1)...Tubular pile, (2)...Earth pushing tool, (3)...Ground, (3a)...Soil entering the pile , (4)...Hose, (5)...
...Balloon-shaped body, (N) ...Press reaction force, (F
)...Expansion force.

Claims (1)

[Claims] 1. Inside the tubular pile (1), the ground (3
) When the cylindrical pile (1) is driven into the pile, the earth and sand (3a) that have entered the pile are pressed down, and when the pressing reaction force (N) exceeds a set value, the pressing reaction force (N) is
) A pile driving method in which the cylindrical pile (1) is driven with an earth pushing tool (2) that moves upward inside the pile attached. 2. The earth pushing tool (2) expands inside the cylindrical pile (1) by supplying pressurized fluid from the connecting hose (4);
Due to the pressure applied to the inner peripheral surface of the pile due to the expansion force (F), the position is maintained inside the cylindrical pile (1) against the pressing reaction force (N) which is less than the set value and which is received from the soil (3a) that has entered the pile. The pile driving method according to claim 1, which uses a holding balloon-shaped body (5).