JPH02311616A - Damping method and pile thereof - Google Patents

Abstract

PURPOSE:To prevent a damping pile from coming to a hindrance to use of a structure by setting up a weight, supporting it with an elastic body, thereby forming the damping pile, and building it into the ground. CONSTITUTION:Concrete is hardened in a hollow pile body consisting of a steel pipe, forming a weight 2. Next, each elastic body 3 consisting of a compression coil spring is set up at both ends of the weight 2, forming a damping pile P. Then, a fundamental structure 8 is set up on the ground 7, and a damping generating machine 6 is installed on a top face of this structure 8, while the damping pile P is buried in a lower surface of the structure 8. In this state, upward reaction force (f) is generated in the weight 2 in relation to downward exciting force F being produced out of this damping generating machine 6, thereby abating vibration in the structure 8, and such a possibility that this exciting force F might be transmitted to the ground 7 is prevented. In addition, when the exciting force F is upward, the reaction force (f) comes to downwardness as in antiphase.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration damping method between a structure and the ground, and a vibration damping resistor used therein.

[Conventional technology]

Conventionally, as a vibration damping means between a structure and the ground, there is one shown in FIG. 10, for example. That is, A is a vibration generating machine, and a weight E is attached via a spring D to the upper surface of a foundation structure C on which this is mounted and installed on the ground B. The dynamic damper generates a reaction force f on the weight E against the excitation force F generated from the vibration-generating machine A, thereby reducing the vibration of the foundation structure C, and the excitation force F is applied to the ground. This prevents the information from being transmitted to B.

[Problems to be Solved by the Invention] However, in the conventional vibration damping means, a dynamic damper is installed on the foundation structure C and around the vibration-generating machine A. There was a problem in that it interfered with work and other tasks when using it.

Therefore, the present invention aims to solve the problems of the prior art by building a vibration damping mechanism into the ground on which a structure is constructed.

[Means to solve the problem]

The invention of the vibration damping method involves arranging a weight inside a hollow antibody so as to be able to move forward and backward in the axial direction of the antibody, and supporting the weight with an elastic body against the antibody. A damping pile is constructed by setting the natural frequency of the mass-spring system to match the frequency of the vibration to be damped, and this damping pile is built into the ground on which the structure will be built, and the structure and ground are The vibration transmitted from one side to the other causes a reaction force on the weight to reduce the vibration.

In addition, the invention of a vibration damping resistor that is directly used to carry out the invention of the method is to arrange a weight inside a hollow antibody so as to be able to move forward and backward in the axial direction of the antibody, and to attach the weight to an elastic body relative to the antibody. The natural frequency of the mass-spring system of the weight and the elastic body is set to match the frequency of the vibration to be damped.

Furthermore, in the invention of the vibration damping pile, it is preferable that a vibration damper is interposed between the weight and the antibody. As a vibration damper, a cylinder tube containing a fluid is connected to one of the weight and the antibody, a piston connected to the other is inserted into the cylinder tube to divide the inside of the cylinder tube into two, and a cylinder tube is opened in the piston. It is preferable that the damping effect be produced by utilizing the fluid throttling action of a closed orifice or choke.

[Effect]

In the invention of the vibration damping pile, when the vibration of the frequency to be damped is input to the antibody, the mass consisting of the weight and the elastic body
In order to overcome the natural frequency of the spring system, the weight vibrates with the elastic deformation of the elastic body, and the vibration of the weight appears in the opposite phase to the input vibration. On the other hand, the vibration of the weight acts as a reaction force. Therefore, the vibration input to the antibody is reduced by the reaction force of the weight. When the weight vibrates, the weight vibrates while being guided in the axial direction of the antibody inside the antibody, so that the direction of vibration is only in the axial direction of the antibody.

By interposing a vibration region "decrease" between the weight and the antibody in the damping pile, the kinetic energy of the weight that continues to vibrate even when the vibration input to the antibody stops,
The vibration damper dampens and stops the vibration of the weight.

Therefore, the antibody is prevented from being excited by the vibration of the weight after the input vibration has stopped.

When such vibration damping piles are built into the ground on which a structure will be built,
Vibration transmission between the structure and the ground is prevented. In other words, if the structure is a foundation structure such as a vibrating machine or a railway, vibrations transmitted to this foundation structure are damped by damping piles to prevent the vibrations from being further transmitted to the ground. In addition, ground vibrations caused by civil engineering work, earthquakes, etc. are damped by damping resistors to prevent vibrations from being transmitted to foundation structures such as houses.

In either case, the damping piles are buried in the ground and do not protrude above the ground, so they do not interfere with the use of the structure or interfere with its appearance.

〔Example〕

FIG. 1.2 is a diagram showing an example of a damping pile P.

In the figure, 1 indicates a hollow antibody, which in this example is made of a steel pipe. Inside this pile body 1, a steel pipe 2
A weight 2 made of hardened concrete 2b is placed inside a. Elastic bodies 3 made of compression coil springs are arranged between both ends of the weight 2 and the lids 1a and lb at both ends of the pile body 1, and the weight 2 is elastically supported by the elastic bodies 3. There is. The elastic body 3 may be a tension spring that supports the weight 2, or may be a spring of another type instead of a coil, or may be a rubber spring. Of course, the weight 2 can be entirely made of steel or concrete.

A roller 4 is rotatably supported on the inner surface of the antibody 1, and this roller 4 contacts the outer circumferential surface of the weight 2 at three points in the circumferential direction, thereby allowing the weight 2 to freely move forward and backward in the axial direction of the antibody 1. being guided. In this embodiment, the rollers 4 guide the weight 2 in its forward and backward movement, but it may be guided not only by rotation like the rollers 4 but also by sliding like a rail.

Furthermore, a vibration damper 5 is installed between 1ila and Ib of the antibody 1 and the weight 2. This vibration damper 5 has a cylinder tube connected to one of the lids 1a and Ib and the weight 2 to contain a fluid, and a cylinder tube connected to the other and contained in the cylinder tube to divide the inside thereof into two parts. The damping effect is produced by utilizing the fluid throttling action of an orifice or choke provided in the piston. This vibration damper 5 is intended to prevent the vibration of the weight 2 from continuing even after the input vibration to the antibody 1 has stopped, and is not intended to dampen the vibration to the pile body 1. , the damping force is sufficient to damp the vibration of the weight 2.

The mass-spring system including the weight 2 and the elastic body 3 has its natural frequency set to match the frequency of the vibration to be damped by the damping pile P. The frequencies to be damped are shown in the attached table, for example.

Since the natural frequency of the mass-spring system is determined by the mass of the weight 2 and the spring constant of the elastic body 3, it is sufficient to determine these according to the vibration to be damped. When there is a range of frequencies as shown in the above table, it is sufficient to select the frequency that should be most damped within that range and then set the corresponding natural frequency of the mass-spring system.

Note that if a plurality of mass-spring systems as shown in FIG. 9, which will be described later, are provided, a plurality of frequencies to be damped can be selected.

When the vibration of the same frequency as the set natural frequency of the mass-spring system of the damping resistor P is input to the pile body 1, the weight 2 resonates without deforming the elastic body 3. , the vibration phase is opposite to the input vibration and damps the input vibration. The vibration of the weight 2 at this time is guided by the transfer of the roller 4 with respect to the outer peripheral surface of the weight 2. Furthermore, when the input vibration to the pile body 1 stops, the vibration of the weight 2 itself is damped and stopped by the action of the vibration damper 50 between the antibody 1 and the weight 2, so the weight continues to vibrate indefinitely. There isn't.

Although the void inside the pile body 1 is filled with air, it can also be filled with inert gas, liquid oil, etc. if necessary for internal rust prevention.

FIG. 3 shows a first embodiment of a vibration damping method using the vibration damping resistor P.

6 is a vibration generating machine, and a damping resistor P is buried in the underside of a foundation structure 8 on which this machine is mounted and installed on the ground 7, and a downward excitation force F generated by the vibration generating machine 6 is On the other hand, by generating an upward reaction force r in the weight 2, the vibration of the foundation structure 8 is reduced and the transmission of the excitation force F to the ground 7 is prevented. It goes without saying that when the excitation force F is upward, the reaction force f is downward with an opposite phase.

In the first embodiment, the excitation force is in the vertical direction, but in FIG. 4 showing the second embodiment, the excitation force is in the vertical direction Fv and the horizontal direction Fh. In this case, a damping resistor Pv installed long in the vertical direction is used for the excitation force in the vertical direction Fv, and a damping resistor installed long in the horizontal direction is used for the excitation force in the horizontal direction Fh. The piles PH are used to attenuate vibrations in all directions. Vibration damping resistance Pv
, Ph are the same as described above with respect to FIG. In addition, in the first and second embodiments, each damping resistance P
For some of them, if the natural frequency of the mass-spring system is made different from that of the others, it is possible to damp vibration inputs having a plurality of frequencies.

FIG. 5 shows a third embodiment of the damping method, in which a damping pile P is buried in the ground 7 as a foundation pile for a structure 9 such as an apartment complex. Two vibration damping piles P are connected to each other so that the lower end reaches the supporting ground, and a structure 9 is constructed on top of the vibration damping pile P. Thereby, vibrations from earthquakes and other earthquake sources are attenuated by the damping resistor P, and the structure 9 is prevented from vibrating.

Figure 6.7 shows a fourth embodiment, in which damping piles P are buried in a row in the ground between a factory 11, which is a source of vibration, and a house 12, so as to isolate the gap between the two. be. In this case as well, the vibrations generated and transmitted from the factory 11 are attenuated by the row of vibration damping piles P and are not transmitted to the house 12.

FIG. 8 is a diagram illustrating an example of the procedure for burying the damping pile P in the ground 7.

First, as shown in (a), a hole is drilled in the ground 7 using an excavating machine such as an earth auger 13, and after the drilling is completed, as shown in (b), a foot hardening solution is injected, and then, as shown in (C), The earth auger 13 is pulled out while discharging the cement milk 15 on top of the soil auger 14 and preventing the collapse of the hole wall. After that, as shown in (d), install the damping pile P into the hole,
Finish by hitting it lightly with a hammer 16 as shown in (e). The above is an example of the procedure for burying the damping pile P, and it goes without saying that the damping pile P can be buried using other procedures.

FIG. 9 shows another example of the damping resistor P, in which one pile body 1 is provided with two sets of mass-spring systems having different natural frequencies. In other words, the frequency of vibration to be damped is different for the upper pair of weight 2 and the elastic body 3 that supports it, and the lower pair of weight 2 and elastic body 3 that supports it. Two types of vibrations having different vibration frequencies can both be attenuated. For example, each vibration of machine A and machine B, which have different vibration frequencies, is damped, and
This will attenuate the vibrations of both the train running at 0knl and the train running at 100h per hour. By increasing the number of spring-mass system pairs, it is possible to attenuate three or more types of vibrations.

The inventor performed the following calculation to confirm the damping effect. The calculation model is shown in Figure 11.
FIG. 1(a) is a diagram corresponding to FIG. 3, in which a foundation structure 8 supporting a vibration generating machine 6 is supported by damping piles P built into the ground. There are two damping piles P in the illustration, but in this calculation there are five, and the outer diameter of each damping pile P is 40.
0 mm, cross-sectional area 0.28 n-r, volume 1.4
m', and the weight is 3.4 tons. FIG. 11(b) is a model of FIG. 11(a), in which the masses of the vibration generating machine 6 and the foundation structure 8 are set to M2. The total mass of the weights 2 of each vibration damping pile P is Ml, the spring constant of the elastic body of each vibration damping pile P is 1, and the spring constant of the ground is 2.

Furthermore, this is modeled for calculation as shown in FIG. 11(C).

The calculation conditions at this time are: ■ When the damping pile P is not used The vibration generating machine 6 and the foundation structure 8 have a weight of 78.1 t, a damping rate of 5%, a spring constant of 3141.7 t/cm, and a natural frequency of f0 was 31.6Hz.

■When using damping pile P, the weight of the damping pile is 17 tons, damping is 5% (Note 1), and spring constant is 6.
83.2 t/cm (Note 2), and the vibration generating machine 6
The weight of the foundation structure 8 is 78.1 as in the case of (■) above.
t, damping 5%, spring constant 3141, 7t 7cm.

Note 1: The optimum damping of the damping pile is ζ0.05→
5% Note 2: When the spring constant of the damping pile is set to the natural frequency f6 of ■ above, = 683.2t/cm ■It An excitation force of 31.6Hz is applied to the foundation structure 8. I took it as a thing.

The calculation results in the above case are as follows.

This result is shown in FIGS. 12 and 13. Here, M is the total mass of the vibration generating machine and the foundation structure, C is the damping constant of the ground, and K is the spring constant of the ground. FIG. 12 shows the case where damping piles are not used, in which (a) shows the relationship between displacement and time, and (b) shows the relationship between acceleration and time. Also, Figure 13 shows the case where damping piles are used,
(a) shows the relationship between displacement and time, and (b) shows the relationship between acceleration and time.

In this way, based on the inventor's calculations, the use of vibration damping piles reduces vibration acceleration and displacement by one-fifth to one-sixth.
It is understandable that this is suppressed.

〔Effect of the invention〕

As explained above, in the invention of the vibration damping pile and vibration damping method, by configuring the vibration damping mechanism as a pile, this is built into the ground on which the structure is constructed. , the vibration damping mechanism does not protrude above or around the machine or structure, so it does not interfere in any way, and in addition to preventing vibrations from the structure from being transmitted to others,
Vibrations from other sources are also prevented from being transmitted to the structure.

Furthermore, by interposing a vibration damper between the weight and the antibody, the weight is prevented from continuing to vibrate even after the input vibration has stopped, thereby preventing the generation of secondary vibrations due to the weight. be able to.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the antibody, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a longitudinal sectional view showing the first embodiment of the vibration damping method.
4 is a vertical sectional view showing the second embodiment, FIG. 5 is a joint sectional view showing the third embodiment, FIG. 6 is a plan view showing the fourth embodiment, and FIG. Longitudinal cross-sectional view of FIG. 8(a) to (e)
is an explanatory diagram of an example of the procedure for burying a damping resistor in the ground, Fig. 9 is a joint cross-sectional view showing another example of a damping resistor, Fig. 10 is a vertical cross-sectional view showing a conventional example, and Fig. 11 is a calculation diagram. Figure 12 (a) is a waveform diagram showing the change in displacement with respect to time when no resistor is used, Figure 12 (b) is a waveform diagram showing the change in acceleration, and Figure 13 ( (a) is a waveform diagram showing a change in displacement amount with respect to time when a pile is used, and (b) is a waveform diagram showing a change in acceleration. P... Anti-vibration, ■... Antibody, 2... Weight, 3...
・Elastic body, 4... Roller, 5... Vibration damper, 6.
... Vibration generating machine, 7... Ground, 8... Foundation structure, 9... Structure. Figure 3 Figure 8 (G) (b) (C) (d) (e) 9th
times

Claims (3)

[Claims] (1) A weight is placed inside the hollow antibody so that it can move forward and backward in the axial direction of the antibody, and this weight is supported by an elastic body against the antibody, so that the weight and the elastic body form a mass-spring system. A damping pile is constructed by setting the natural frequency of the damping pile to match the frequency of the vibration to be damped, and this damping pile is built into the ground on which the structure will be built, and the vibration from one side of the structure and the ground is set. A vibration damping method characterized in that the vibrations are reduced by generating a reaction force in the weight due to the vibrations transmitted to the other weight. (2) A weight is placed inside the hollow antibody so that it can move forward and backward in the axial direction of the antibody, and this weight is supported by an elastic body against the antibody, so that the mass-spring system of the weight and the elastic body A vibration damping pile characterized in that its natural frequency is set to match the frequency of the vibration to be damped. (3) A weight is placed inside the hollow antibody so that it can move forward and backward in the axial direction of the antibody, and the weight is supported by an elastic body against the antibody, so that the mass-spring system of the weight and the elastic body A vibration damping pile characterized in that the natural frequency of the vibration damping pile is set to match the frequency of the vibration to be damped, and a vibration damper is interposed between the weight and the antibody.