JPH0526893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a method for driving and pulling out underground penetrating members such as piles, and more particularly to a method for driving and pulling out underground penetrating members using complex vibration.

<<Prior Art and Problems>> As is well known, there is a vibration method as a construction method for driving underground penetrating members such as piles made of steel pipes, H steel, concrete, etc., or steel sheet piles into the ground.

In this type of construction method, a vertical oscillator is generally used, which applies the vertical and reciprocating vibrations generated by the vertical oscillator to the underground penetrating member, reducing the peripheral surface friction force of the penetrating member as much as possible, and using the excitation force. The inertial force generated in the oscillator and the penetrating member is used to penetrate into the ground.

However, when a vertical oscillator is used to drive an underground member into the ground, it is easy to penetrate the ground and can be driven in a short time when the ground is soft, sticky or sandy.

However, if the ground is hard, or if the ground is of the above geology but has a relatively hard layer in the middle, it will be difficult to penetrate and it will take a significant amount of time.

Conventionally, the solution to this problem was to use auxiliary methods such as pre-boring with a water jet or auger, or to drive the penetrating member to a predetermined depth using a large vertical oscillator. This method requires a larger casting machine, and
Economic disadvantage increases.

Therefore, the applicant has already filed a patent application filed in 1983-
Publication No. 86645 discloses a construction method that makes it possible to easily drive and pull out underground penetrating members even in difficult ground by applying a compound vibration that is a combination of vertical vibration and torsional vibration. .

However, this method also had the following problems.

In other words, the oscillator used in this construction method is
Since the oscillation shafts with eccentric weights are arranged in two stages, upper and lower, the vertical length is increased by one stage, and the pile length is sacrificed by an amount corresponding to this length.

<Object of the invention> This invention has been made in view of the above-mentioned conventional problems, and its object is to:
By placing the oscillation axis of the oscillator in the same plane,
It is an object of the present invention to provide a method for driving and pulling out underground penetrating members, which solves the problem of pile length, facilitates remote control, and improves construction ability.

<Structure of the Invention> In order to achieve the above object, the method for driving and pulling out underground members of the present invention is applicable to driving and pulling out members for underground penetrating members such as piles such as steel pipes and H steel, and steel sheet piles. At the upper end of the underground penetrating member, four oscillation shafts each having an eccentric weight and rotatably supported are installed. The oscillation axes of each front and rear pair are rotated in the same direction and at the same number of rotations, and the oscillation axes of each front and rear pair are rotated in the same direction and at the same rotation speed. These phase angles are adjusted so that the secondary oscillation axis at one diagonal position has the same phase difference in the rotational direction of each front and rear pair with respect to the main oscillation axis at the other diagonal position. A compound vibration oscillator that changes the
When driving or pulling out the underground penetrating member becomes difficult due to changes in the strata, the phase difference between the secondary oscillation axis and the main oscillation axis is changed by remote control without stopping the driving of the compound vibration oscillator. Accordingly, the penetrating member is driven into the ground or pulled out from the ground while changing and adjusting the direction of the composite vibration in the vertical direction and the torsional direction.

<<Example>> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a method for driving an underground penetrating member according to the present invention into the ground where it is difficult to drive.

The ground 10 has a hard ground layer 12 in the middle part, and a support layer 14 exists below the hard ground layer 12.

In the same figure, reference numeral 16 is a mobile base machine for suspending underground penetrating members, etc., and a hanging wire 1
8. A composite vibration oscillator 22 is suspended via a buffer 20.

In this embodiment, a cylindrical steel pipe pile 24 is used as the underground penetration member, and the lower end is formed to have a slightly larger diameter than the pile 24, and has a cross shape with a sharp tip, which protrudes outward from the pile. A cone 26 having ribs is fitted, and its upper end is connected to the compound vibration oscillator 22 via a connector 28.

The above-mentioned compound vibration oscillator 22 is disclosed in Japanese Patent Application No. 136481/1983 by the applicant of the present application, and has a general configuration of four vibration oscillators each having an eccentric weight and each rotatably supported. The oscillation axes are arranged in a plane in the front, back, left and right so that each pair of oscillation axes arranged in the front and back direction are in the same direction and their respective axes are parallel, and any one of these oscillation axes is As a drive shaft, the oscillation shafts of the front and rear pairs are rotated in the same direction, and one of the front and rear pairs is rotated in the opposite direction, and the number of rotations of each oscillation shaft is the same. The system transmits rotational force to the middle of the four oscillation shafts arranged on the front, rear, left and right sides, and also remotely controls the pair of oscillation shafts located on one diagonal while the oscillation shafts are in operation. The phase angles of these oscillation axes with respect to a pair of oscillation axes located on the other diagonal can be adjusted by simultaneously rotating the oscillation axes by an angle. It is characterized by the interposition of a power transmission section composed of a plurality of spur gears.

The principle of generation of complex vibrations of this oscillator 22 is shown in FIG.

In the figure, four oscillation axes A, A', B, and B, each having an eccentric weight W of the same weight, are connected to the axes of a pair (A and B', B and A') disposed in the front-rear direction. The oscillation axes A, A', B, and B' rotate at the same rotation speed in the direction of the arrows. Rotate.

That is, the oscillation axes of the front and rear pairs (A and B', B and A') rotate in the same direction, and the left and right oscillation axes (A and B,
A′ and B′) have opposite directions of rotation.

Here, the oscillation axes A and A' located diagonally are called the main oscillation axes, and B and B' are called the auxiliary oscillation axes. It is assumed that these phase angles can be changed simultaneously so that the phase difference is the same in the pair of rotation directions.

First, when the phase angles of the main oscillation axes A, A' and the sub oscillation axes B, B' are the same (the phase difference is zero), each oscillation axis A,
A', B, B' are Figure 1 a-1, a-2, a-3,
It rotates in the state shown in a-4.

At this time, the excitation force due to the centrifugal force of the eccentric weight W is caused by the excitation force in the torsional direction acting in the opposite direction and becoming zero, as shown in Figure a-2 and a-4. Acts only in the direction.

Next, when the phase difference between the main oscillation axes A and A' and the reverse oscillation axes B and B' is π (180°), each eccentric weight W is , c-4.

In this case, the excitation force in the vertical direction is c-
As shown in 1 and c-3, since the directions are opposite and the magnitudes fluctuate equally, they cancel each other out and become zero.

However, the excitation force in the torsional direction is c-2 in the same figure,
As shown in c-4, they are in the same direction and become the resultant force of the left and right oscillation axes (A and B, A' and B').

Furthermore, when the phase difference between the main oscillation axes A, A' and the sub oscillation axes B, B' is π/2 (90°), each eccentric weight W is -3, rotates in the state shown in b-4.

In this case, the amplitude of the excitation force in the vertical direction and the excitation force in the torsional direction is smaller than when the phase difference is zero or π, but the excitation force in the vertical direction has the same period. When it reaches its maximum, the excitation force in the torsional direction also changes to its maximum.

Furthermore, when the phase difference is 0 < θ < π/2, the excitation force in the vertical direction becomes the main force, while when π/2 < θ < π, the excitation force in the torsional direction A complex vibration mainly caused by force occurs.

This complex vibration mode can be set arbitrarily by selecting the phase difference θ, and an appropriate vibration mode can be obtained depending on the properties of the ground.

To drive the steel pipe pile 24, up and down reciprocating vibration X is used as in the conventional construction method until the cone 26 of the steel pipe pile 24 reaches the hard ground layer 12.

When the tip end 26 of the steel pipe pile 24 hits the hard ground layer 12 and driving becomes difficult, the drive of the compound vibration oscillator 22 is stopped by the control device 30 installed on the ground. By changing the relative position of the eccentric weight of the oscillation shaft on one diagonal of the oscillator 22, the vertical reciprocating vibration X,
A composite vibration Z, which is a combination of the torsional reciprocating vibration Y and the torsional reciprocating vibration Y, is applied to the steel pipe pile 24.

Here, the vibration mode of the compound vibration Z is set to be suitable for the hard ground layer 12, so that the vertical reciprocating vibration X transmits the inertia of the oscillator 22 and the steel pipe pile 24 to the tip cone 26, ground layer 1
2 is destroyed and the pile 24 is penetrated, and the peripheral surface frictional resistance of the pile 24 is significantly reduced by the vertical reciprocating vibration X.

At the same time, the torsional reciprocating vibration Y is caused by the pile 2
The four tip cones 26 act to shear and fracture the ground layer 12, and their synergistic action allows the steel pipe pile 24 to penetrate even the hard ground layer 12 easily and in a short time.

Then, when the steel pipe pile 24 reaches the predetermined support layer 14, the driving ends.

In addition, as in the above-mentioned embodiment, if there is a hard ground layer 12 in the middle of the ground 10 in the depth direction, it may be confirmed by conducting a geological survey before driving the piles 24. The amount of penetration of the pile 24 is continuously measured, and when the pile 24 reaches the hard ground layer 12, the amount of penetration changes, so this may be detected and the control device 30 may be operated as described above.

On the other hand, the method shown in FIG. 3 is used to pull out the steel pipe pile 24 driven into the ground 10.

The state shown in the figure is a state in which the steel pipe pile 24 is driven into the ground 10, which is difficult to pull out, such as a clay layer. A composite vibration oscillator 22 suspended from the base machine 16 is connected to the base machine 16 by a coupling member 28.

Thereafter, by driving the composite vibration oscillator 22 and applying a composite vibration Z, which is a combination of the vertical reciprocating vibration X and the torsional reciprocating vibration Y, to the steel pipe pile 24 and pulling it upward, it can be easily pulled out.

Also in this case, the vibration mode of the complex vibration Z is set according to the properties of the ground 10 into which the pile 24 is driven.

Now, in the method of the present invention configured as described above, the driving and pulling out of the steel pipe pile 24 can be carried out easily and in a short time, and the vibration mode of the compound vibration Z generated by the compound vibration oscillator 22 while the pile 24 is being driven. can be set arbitrarily over a wide range without stopping the drive of the oscillator 22, so construction can be performed in a state where efficiency is most improved depending on construction conditions such as the penetration state of the piles 24 and changes in ground properties.

In addition, by attaching the cone 26 to the tip of the steel pipe pile 24 as described above, the amount of fracture penetration into the ground can be increased, and the friction force on the pile circumferential surface can be reduced due to the ground breaking of the outer circumferential rib of the cone 26. ,
The shear disturbance effect due to torsional reciprocating vibration Y increases,
The strength of the ground such as cohesive soil is reduced, and the driving performance of the compound vibration oscillator 22 is further improved.

In addition, although the steel pipe pile 24 was illustrated as an underground penetration member in the said Example, the Example of this invention is not limited to this, A concrete pile, a steel sheet pile, etc. may be sufficient.

In particular, when applied to driving and pulling out steel sheet piles, the following effects can be obtained.

In other words, in driving and pulling out steel sheet piles,
In addition to the properties of the ground, engagement with adjacent steel sheet piles is required, and if driving and pulling out is done only by vertical vibration However, these obstacles can be eliminated by the complex vibration Z that includes the torsional reciprocating vibration Y, and the work can be carried out smoothly.

<<Effects of the Invention>> As explained above in detail in the embodiments, according to the method of driving and pulling out underground penetrating members according to the present invention, four oscillation shafts arranged in a plane are used. Therefore, it is possible to reduce the height of the compound vibrator that generates compound vibrations, and by simultaneously rotating the slave oscillation shaft located at one diagonal position, the synchronization state of the oscillator shaft located at the diagonal position can be maintained at all times. It is possible to obtain special effects such as being able to easily hold and remotely control, and to quickly respond to changes in the strata and easily drive and pull out the underground penetrating member.

[Brief explanation of the drawing]

FIG. 1 shows the driving state of a pile according to the present invention, in which FIG. 1A is an overall view and FIG. FIG. 2 is a diagram explaining the principle of a compound vibration oscillator. FIG. 3 is an explanatory diagram when the pile according to the present invention is pulled out. 10... Ground, 12... Hard ground, 14... Support layer, 16... Base machine, 18... Hanging wire, 20... Buffer, 22... Complex vibration oscillator,
24... Steel pipe pile, 26... Cone, 28... Connector, 30... Control device.

Claims (1)

[Claims] 1. In the driving and pulling method of underground penetrating members such as steel pipes, H-steel piles, steel sheet piles, etc., four pieces each having an eccentric weight and rotatably supported at the upper end of the underground penetrating member are used. The oscillation axes are arranged in a plane in the front, rear, left and right so that the axes of each pair arranged in the front and back direction are in the same direction and the axes of each front and rear pair are parallel. They are rotated in the same direction and at the same number of rotations, and the other is rotated in the opposite direction and at the same number of rotations relative to one front and rear pair.
In addition, these phase angles are changed simultaneously so that the secondary oscillation axis located at one diagonal position has the same phase difference with respect to the main oscillation axis located at the other diagonal position in the rotation direction of each front and rear pair. removably attach the composite vibration oscillator, drive the underground penetration member,
When extraction becomes difficult due to changes in the strata, the phase difference between the secondary oscillation axis and the main oscillation axis can be changed by remote control without stopping the driving of the compound vibration oscillator. A method for driving and pulling out underground penetrating members, characterized by driving the penetrating member into the ground or pulling out the penetrating member from the ground while changing and adjusting the direction of the composite vibration in the up direction.