JP2000204552A - Pollution-free pile-driving method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pollution-free pile-driving method and device capable of exhibition the maximum working efficiency within a regulated value while keeping vibration and noise in a pollution control target place in the vicinity of a piling construction position within regulated values. SOLUTION: In a vibration exciter 2 giving vibration to a pile 1, the Amplitude and the frequency of the vibration can be mutually independently adjusted. A vibration pickup 8 and a microphone 9 are installed at a pollution control target place in order to detect from moment to moment vibration a-d continuously varying in accordance with the settlement of the pile 1 and input the vibration into a controller 10. The controller 10 controls separately the amplitude and the frequency of the vibration generated from the vibration exciter 2 lest that the vibration caught by the vibration pickup 8 should exceed a regulated value and further the noise caught by the microphone 9 should exceed a regulated value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of preventing vibration and noise pollution in a vibratory pile driving work in which a vibration exciter is attached to a pile and the pile penetrates into the ground.
And the apparatus.

[0002]

2. Description of the Related Art Vibratory pile driving methods and press-fitting pile driving methods which are most frequently used at present are methods of penetrating ready-made piles into the ground and driving them. There are other methods such as a drop hammer method and a diesel hammer method. However, since a great deal of vibration and noise are generated, the construction is significantly restricted. Focusing on the fact that the above-mentioned techniques of the press-fitting pile driving method and the vibrating pile driving method are almost directly applied to pulling out piles, they are often referred to as a press-fitting pile punching method and a vibrating pile punching method. Although the pile driving method according to the present invention was created for the non-polluting driving of a pile, it can be easily applied to the pulling of the pile, and belongs to the technical scope of the present invention. is there. That is, the term “pile driving” in the present invention is a broad concept and includes a concept of pulling out. The press-fitting pile driving method and the vibrating pile driving method have respective lengths and shortnesses.However, from a general viewpoint, the vibrating pile driving method is stronger than the press-fitting pile driving method, and the pile driving method is carried out in a relatively hard ground. Can be cast. Instead, the vibration pile driving method generates more vibration and noise than the press-fitting pile driving method.

[0003] In the above-mentioned vibration pile driving method, a vibration exciter is attached to a pile (usually at the upper end of the pile), and a longitudinal vibration is applied to the pile to cause the pile to penetrate the ground. The above-mentioned exciters can be roughly classified into an eccentric weight type (also known as a pendulum type) and a cylinder type (also known as a hydraulic type or a piston type). The basic structural function of the eccentric weight type vibration exciter is to rotate a pair of eccentric weights in opposite directions at a constant speed to each other,
The centrifugal force in the horizontal direction of the pair of eccentric weights is cancelled, and the centrifugal force in the vertical direction is superimposed on the pair of eccentric weights to take out the vibration (specifically, the rotation axis of the rotating shaft supporting the eccentric weights). Vibrating the casing through the bearings). Further, the cylinder type vibrator is provided with cylinder means between a reaction force weight for supporting a reaction force by inertia force and a chuck for holding a pile, and supplies fluid energy via a servo valve to supply the cylinder means. Vibrates the pile by repeatedly expanding and contracting.

[0004]

The choice between the press-fitting pile driving method and the vibrating pile driving method, which have been compared and described above, requires the consideration of the construction designer and the decision of the construction manager. Although it is a serious problem, in principle, it is extremely difficult to perform the press-fitting method on hard ground, and in many cases, the vibration pile driving method must be used. However, when a vibrating pile is driven in a place such as near a hospital or near a railway having automatic control equipment, it is important and difficult to prevent vibration and noise generated during the vibrating pile driving method. In order to solve such a problem, there has been proposed a technique capable of increasing and decreasing the vibrating force without stopping the operation when constructing a vibrating pile. Japanese Patent Application Laid-Open No. 7-1995 describes an example of a technique for adjusting the vibrating force of an eccentric weight type vibrator.
Japanese Patent Application Laid-Open No. 141035 is known, and as an example of a technique for adjusting the vibrating force of a cylinder type vibrator, see Japanese Unexamined Patent Publication No.
No. 9514 is known, but this known technique does not disclose a technical idea of controlling the vibration so as to be within a regulation value.

[0005] For example, when an attempt is made to perform a vibratory pile driving work in an area where noise and vibration regulations are extremely severe, such as in the vicinity of a hospital or a school or near a railway line of an automatic control system, a vibration exciter according to the above-mentioned known technique is used. Adjust the vibrating force of
If the vibration and noise are suppressed within the regulation values, the penetrating force for sinking the pile into the ground decreases with the decrease in the vibrating force, and the pile driving work may not proceed. Further, in many cases, the sinking speed is significantly reduced, and the working efficiency is reduced. In such a case, even if an attempt is made to use a press-fitting pile driving method with less vibration and noise, the pile cannot be driven by the press-fitting pile driving machine if the ground is relatively hard.

[0006]

In view of the above-mentioned circumstances, it is possible to suppress vibration and noise within regulated values by using a vibrating pile driving method having a relatively large force for penetrating a pile into the ground as a base. The present inventors first clarified the mechanism of the generation of vibration pollution in order to increase the working efficiency by generating the maximum vibrating force within a proper range. FIG. 3 is a schematic vertical cross-sectional view of a vibrating pile driving work shown to explain the appearance of the vibration pollution generation. FIG. 3 (A) shows the lower end of the pile at the initial stage of the driving in the clay layer of the surface layer. (B) depicts a state in which the lower end of the pile at the middle of the driving is in the silt layer, and (C) shows a state in which the lower end of the pile at the end of the driving penetrates the gravel layer, which is the main support layer. The state and the crane boom are depicted. The vibration is generated by the exciter 2 and transmitted to the pile 1, but the vibration transmitted to the pile 1 does not reach the person on the ground as it is, and the vibration is also generated by friction between the pile and the ground 5, Vibration occurs when the lower end of the pile crushes or consolidates the formation. In addition, the clay layer 5a, the silt layer 5b, and the sand layer 5 forming the ground 5
The situation differs depending on each of the c and the gravel layer 5d. A part of the vibration generated by the exciter 2 is
Through the crane boom 3 and causes various troubles when it resonates.

FIG. 4 is a view for explaining a state in which the pile vibration changes depending on the stratum. FIG. 4 (A) is a vibration waveform chart in a state where the lower end of the pile faces relatively soft ground. (B) is a vibration waveform chart in a state where the lower end of the pile faces the relatively hard ground (gravel layer). Pile vibration when penetrating into relatively soft ground (Figure A)
Is a waveform close to a sine wave, but it is in a state close to free vibration at the point where the pile turns from rising to falling,
The waveform shows that the pile has undergone a considerable amount of repulsion at the point where it turned from descending to ascending. As described above, the repulsion that the pile receives from the ground is more remarkable in the hard ground as shown in FIG. 6B, and in this example, the harmonics are clearly shown. When comparing the vibration waveform of FIG. 7A and the vibration waveform of FIG. 6B, there is no significant difference in the amplitude, but when the maximum value of the acceleration is compared, when the ground is hard as shown in FIG. It is clearly increasing. As described above, when focusing on the fact that the vibration characteristics change in accordance with the soil change in the ground, even if one pile is driven into the same spot, a harmful level corresponding to the vertical geological change is obtained. It is necessary to control the exciter so as not to generate vibrations and to improve efficiency as much as possible within a range not exceeding the limit value.

[0008] The basic principle of the present invention created based on the above-described elucidation of the mechanism of generating vibration pollution is as follows.
Brief description with reference to FIG. 1 corresponding to the embodiment is as follows. That is, vibration and noise at the point of pollution prevention near the pile driving point are controlled within the regulation value, and the pile 1 is vibrated to exert the maximum working efficiency within the regulation value. The machine 2 has a structure capable of adjusting the amplitude and frequency of the vibration independently of each other. On the other hand, the vibration pickup 8 and the microphone 9 are installed at the pollution prevention target, and the vibration a changes as the pile 1 sinks.
Ｄd are detected every moment and input to the control device 10. The control device 10 controls the amplitude of the vibration generated by the vibration exciter 2 so that the vibration captured by the vibration pickup 8 does not exceed the regulation value and the noise captured by the microphone 9 does not exceed the regulation value. And the frequency are individually controlled.

In order to achieve the above-mentioned object based on the above-described principle, the construction method according to the first aspect of the present invention is to mount an exciter of a type of generating vibration by rotating an eccentric weight on a pile, In the pile driving method in which the above-mentioned pile is given its longitudinal vibration to penetrate the ground, the vibrating force is controlled by changing the effective rotational moment of the eccentric weight while rotating the eccentric weight. A vibration exciter having a structure that can be used is used, and a vibration pickup is installed by separating the pile from the setting point of the pile and in contact with the ground, and the vibration exciter is operated to apply vibration to the pile. While penetrating the pile into the ground, the vibration propagating to the vibration pickup is measured, so that the physical quantity representing the measured vibration intensity does not exceed a predetermined limit value, and Within the range of the value, Adjust the effective rotational moment to approach the value, and controlling the vibratory force of the exciter. According to the invention method of the first aspect described above, the frequency of the vibration generated by the vibration exciter matches the rotation speed of the eccentric weight. Therefore, by adjusting the effective rotational moment of the eccentric weight while rotating the eccentric weight at the same rotation speed, the amplitude can be changed while the frequency of the generated vibration is kept constant. Regulation of vibration intensity to prevent pollution may be indicated by amplitude, vibration acceleration, or decibel, but in any case, the effective eccentric moment Can be varied to change the physical quantity representing the vibration intensity independently of the vibration frequency. Thus, it is extremely important in practical use to be able to change the vibration frequency and the amplitude strength independently of each other. The reason is that, for example, when the vibration intensity is adjusted by changing the rotation speed to change the vibration acceleration, if the amplitude is changed to the desired strength, the frequency changes involuntarily. As a result, the frequency of the vibration generated by the exciter resonates with the natural frequency of the ground to amplify the vibration pollution, or resonates with the boom of the crane that holds the exciter, and This is because there is a great risk of damaging the device. According to the construction method of the present invention, the intensity of vibration is suppressed without fear of inducing an unexpected serious trouble,
Not only can the pollution control value not be exceeded, but also when a single pile is made to penetrate into the ground, the stratum in contact with the pile changes as the penetration progresses, The exciter should be controlled so as to generate as strong vibration as possible within the limit (pollution regulation value) that does not cause pollution, in accordance with the vibration engineering characteristics of the partner stratum that is changing to Can be. As a result, it is possible to improve the efficiency of the pile driving work while preventing vibration and noise pollution. The excellent practical effects described above are:
From the conventional technology of simply detecting vibration / noise and controlling the vibrating force of the vibration exciter, the vibration frequency (rotational speed of the eccentric weight) and amplitude (effective eccentric moment of the eccentric weight) are further advanced. This was achieved for the first time by controlling them individually.

[0010] In the pollution-free pile driving method according to the second aspect of the present invention, an exciter of a type that generates vibration by repeatedly expanding and contracting a cylinder or repeatedly returning a piston is mounted on the pile, and the pile is mounted on the pile. On the other hand, in the pile driving method in which the vibration in the longitudinal direction is applied to penetrate into the ground, the amplitude and frequency of the vibration are made independent from each other by changing the hydrodynamic value of the energy source supplied to the cylinder or piston. A vibration exciter that can be controlled is used, and a vibration pick-up is installed by separating the pile from the pile setting point and in contact with the ground, and operating the above-described vibration exciter to apply vibration to the pile. While making the pile penetrate into the ground, measure the vibration propagating to the vibration pickup, and make sure that the physical quantity representing the measured vibration intensity does not exceed the limit value specified in advance. The energy source supplied to the cylinder or the piston is adjusted so as to approach the limit value within the limit value as much as possible, so that the frequency of the vibration generated by the exciter is not changed, and the penetration speed of the pile is It is characterized in that the amplitude is controlled independently of the amplitude. According to the construction method of the invention described above, the frequency of the vibration generated by the vibration exciter is determined by the expansion and contraction of the cylinder or the number of reciprocations of the piston. The amplitude of the generated vibration is determined by the amount of supplied energy per one stroke (pressure × flow rate). Therefore, the amplitude can be changed while keeping the vibration frequency constant. Regulation of vibration intensity to prevent pollution is sometimes expressed by amplitude, sometimes by vibration acceleration, and sometimes by decibels. On the other hand, it is possible to independently increase or decrease the physical quantity representing the vibration intensity. Thus, it is extremely important in practical use to be able to change the vibration frequency and the vibration intensity independently of each other. The reason is that, for example, when the vibration intensity is adjusted by changing the rotation speed to change the vibration acceleration, if the amplitude is changed to the desired strength, the frequency changes involuntarily. As a result, the frequency of the vibration generated by the exciter resonates with the natural frequency of the ground to amplify the vibration pollution, or resonates with the boom of the crane that holds the exciter, and This is because there is a great risk of damaging the device. According to the construction method of the second aspect, not only can the strength of vibration be suppressed without fear of inducing an unexpected serious trouble, so that it does not exceed the regulation value of pollution, but also one pile can be used. When the rocks penetrate into the ground, the stratum in contact with the pile changes as the penetration progresses, so pollution is generated in response to the vibration engineering characteristics of the opposing stratum, which is constantly changing. The exciter can be controlled so as to generate as strong a vibration as possible within a limit (pollution regulation value) that is not allowed. As a result, it is possible to improve the efficiency of the pile driving work while preventing vibration and noise pollution. The excellent practical effects described above are based on the conventional technology of simply detecting vibration and noise and controlling the vibrating force of the vibration exciter, and by further controlling the frequency and amplitude of vibration separately. This is the first time I played.

According to the construction of the invention method according to claim 3, in addition to the constituent features of claim 1 or claim 3, a microphone is installed at a distance from a driving point of a pile and propagates to the microphone. Measure the noise level, suppress the vibrating force of the vibrator so that the value of the noise level measured by the microphone does not exceed a predetermined noise limit value, the noise level measured Is set within a range where the value does not exceed the noise limit value, and the pile is driven by approaching the physical quantity representing the vibration intensity to the vibration limit value. According to the invention method of the third aspect described above, the vibration that occurs along with the penetration of the pile and propagates through the ground to the regulation target point within the limit value is suppressed, and mainly from the vibration exciter. The total amount of the generated construction noise and the background noise that is not caused by the pile driving work is within the noise limit value, and within the range of the condition that each of the vibration and the noise is suppressed within the limit value as described above. It is possible to maximize the efficiency of pile driving work. That is, when the invention method of claim 3 is applied, the unique effect obtained by individually controlling the vibration frequency and the amplitude of the exciter which is the ground vibration source in claim 1 or 2 is obtained. Without impairing, noise regulations can be cleared, and a decrease in work efficiency can be minimized (work efficiency can be improved as much as possible).

According to a fourth aspect of the present invention, in addition to the constituent features of the first to third aspects, the exciter employs an exciter capable of increasing and decreasing the frequency of vibration. While operating the exciter to make the pile penetrate into the ground, test the vibration frequency, and measure the vibration with the vibration pickup while changing it continuously or stepwise.
To determine the frequency range in which the physical quantity representing the measured vibration intensity increases due to the resonance of the ground or the structure, and to operate the vibration exciter to avoid the above resonance frequency range to perform the vibration pile driving work. It is characterized by. According to the invention method of claim 4 described above, even when one pile is vibrated, the other stratum changes as the penetration of the one pile into the ground progresses. In order to avoid the resonance frequency by experimentally grasping the change of the resonance characteristic due to the geological change every moment, it is necessary to prevent the occurrence of troubles due to resonance at the time of pile driving. Can be. As described above, the reason for avoiding the resonance frequency and performing the practical pile driving operation is that the amplitude and the vibration frequency are controlled independently of each other with respect to the vibration control of the exciter. It can be established on the premise of the configuration described above. The reason is that when the vibration frequency generated by the vibration exciter is increased or decreased in order to avoid the resonance frequency, the pile driving work is extremely difficult if the amplitude is involuntarily changed.

According to a fifth aspect of the present invention, in addition to the constituent features of the first to fourth aspects, the resonance of one or a plurality of buildings or structures adjacent to the piling site is determined in advance. Investigating the frequency and performing the vibratory pile driving operation by activating the exciter avoiding the resonance frequency obtained by the investigation and / or a frequency that is a fraction of the resonance frequency obtained by the investigation. Features. According to the invention method of claim 5 described above, it is possible to prevent a building or a structure adjacent to a pile driving point from being unexpectedly damaged. In the fourth aspect of the present invention, the ground vibration is prevented from being unnecessarily amplified harmlessly due to the resonance of a natural object. In contrast, the fifth aspect of the present invention mainly comprises an artificial structure (for example, To prevent houses, bridges, columns, retaining walls, etc.) from being damaged by resonance. In addition, preventing resonance of the construct
In addition to preventing damage to the structure itself, it is possible to indirectly prevent the harm of vibration to the people in it and the easily damaged items installed therein. The practical value of being able to indirectly protect easily damaged items is significant. For example, when a pile driving work is performed near a hospital, even if the vibration of the ground supporting the hospital building is insensitive vibration (acceleration 0.8 gal (about 55 dB) or less), the building resonates. Patients lying in the room receive significant irritation. The fifth aspect of the present invention prevents such an unexpected situation completely and completely, and makes it possible to perform pollution-free pile driving.

According to a sixth aspect of the present invention, in addition to the constituent features of the third to fifth aspects, a plurality or a plurality of piles are cast in an area where there is no significant difference in geological structure. In this case, one or more piles are experimentally driven into the area by the method according to claim 1 or 2 and are defined as a function of the penetration depth of the pile or unambiguous with the penetration depth. The optimal amplitude and / or optimal frequency is determined as a function of the corresponding numerical value, and for piles other than those piled experimentally, the exciter is operated at the optimal amplitude and / or optimal frequency to drive the pile. For piles other than piles that have been constructed or that have been experimentally driven, the vibration is measured by the vibration pickup and the exciter is operated at the optimum amplitude and / or frequency to drive the pile. And shake When the actual measurement value measured by the pickup has reached a pre-specified limit value, which comprises suppressing the vibratory force of the exciter so as not to exceed the limit value. According to the invention method of claim 6 described above, the vibration engineering characteristics of the geological structure in the area are grasped by using the “optimal amplitude and / or optimal frequency” as a parameter by driving a test pile. For most piles other than test piles, precise control for each pile can be omitted, and the piles can be driven without pollution. The invention method of claim 6 is desirably applied when the stratum is substantially parallel. If, after predicting that the stratum structure is simple and parallel and applying the present claim 6 and starting pile driving work, the measured value by the vibration pickup is likely to exceed the vibration limit value, the present claim is made. It is also possible to easily cancel the application of the item 6 and switch to the control of each one.

According to a seventh aspect of the present invention, in addition to the constituent features of the third to fifth aspects, a plurality or a plurality of piles are driven into one or a plurality of sections by a vibrator. In this case, for each pile, the installation work is performed while actually measuring the vibration by the vibration pickup and / or the noise level by the microphone, and generating vibration and noise due to the change in the penetration depth of the pile. -In response to a change in the propagation situation, the exciter is controlled so that the vibration and / or noise level does not exceed the limit value. According to the invention method of claim 7 described above, even if the stratum structure is complex, the construction area is vast, or a plurality of construction areas are dispersed, the pile control can be performed without violating the pollution control. Vibration pile driving work can be performed while minimizing the drop in driving efficiency.
The construction method according to claim 7 can be applied to a case where a plurality of piles are simultaneously driven in parallel by arranging a vibration exciter for each of the plurality of construction sections, and The present invention can also be applied to a case where the exciter is moved and a plurality of construction sections are sequentially traversed while the excavator is driven one by one.

According to an eighth aspect of the present invention, at least one pair of eccentric weights, a drive motor for adjusting the rotation speed for rotating the eccentric weights, and the at least one pair of eccentric weights are provided. Means for adjusting the total eccentric moment by changing the mutual rotational phase difference, in a pile driving device having a vibration exciter, a vibration pickup capable of measuring ground vibration, and an output signal of the vibration pickup being input. And an automatic control device for controlling the total eccentric moment of the eccentric weight and the rotation speed thereof, and the automatic control device has a function of frequency-analyzing the inputted vibration. The value of the physical quantity representing the magnitude of the measured vibration is equal to or less than a predetermined value, and the value of the physical quantity representing the magnitude of the vibration at a predetermined frequency or frequency range is As a serial or less different from previously given value, characterized in that it has a function of automatically controlling the overall eccentric moment and / or rotational speed. According to the apparatus of the eighth aspect described above, the frequency of the generated vibration can be controlled by adjusting the rotation speed of the eccentric weight, and the total eccentric moment of the eccentric weight can be adjusted. Thus, the amplitude of the generated vibration can be controlled, and the frequency and the amplitude of the generated vibration can be individually controlled as described above. For one, the amplitude can be controlled without changing the frequency. Thus, the amplitude can be suppressed to within the regulation value of the vibration pollution. For the same reason, the regulation value of vibration pollution can be cleared whether the regulation value is given by vibration acceleration or decibel. On the other hand, the frequency can be changed while keeping the amplitude or the vibration acceleration at a desired value. Since the frequency can be arbitrarily controlled in this manner, vibration of a desired depth can be generated avoiding the resonance frequency of the ground, and vibration of a desired strength can be generated avoiding the resonance frequency of the building. Applying the present claim, as an overall effect of the above-described operation, the vibration pollution regulation is cleared corresponding to various geological structures, and the work efficiency is maximized within a range that does not conflict with the vibration pollution regulation. Can be improved.

According to a ninth aspect of the present invention, there is provided a pile driving device having a vibration exciter including a cylinder means for generating vibration and a servo valve for adjusting fluid energy supplied to the cylinder means. A vibration pickup capable of measuring ground vibration; and an automatic control device that receives an output signal of the vibration pickup and controls operation of the cylinder means through the servo valve. Has a function of performing frequency analysis with the input vibration, the value of the physical quantity representing the intensity of the measured vibration is equal to or less than a predetermined value, and the frequency or frequency range specified in advance Exciting force via the servo valve, so that the value of the physical quantity representing the vibration intensity is equal to or less than a predetermined value different from the above,
It has a function to control regardless of the penetration speed of the pile. According to the apparatus of the ninth aspect described above, the cylinder means is used (so-called piston type).
Improved vibration pile driver to prevent vibration and noise pollution,
In addition, highly efficient work can be performed within a possible range. In particular, because it has a frequency analysis function, it can operate at the maximum amplitude within the possible range while suppressing vibration in response to the vibration engineering characteristics of the ground, so that pollution regulations can be cleared and work efficiency can be improved. It is possible to achieve both improvement and improvement. The vibration characteristics of the ground are not invariable, and the area of the stratum in contact with the pile increases as the pile penetrates, and the stratum crushed and consolidated by the lower end of the pile changes. Therefore, the device according to the present invention corresponds to the “geologically related to the pile due to vibration engineering” which changes every moment, within a range that does not violate the vibration pollution regulation and the noise pollution regulation in real time. It is possible to carry out the vibration pile driving work with maximum efficiency.

According to a tenth aspect of the present invention, in addition to the constituent features of the eighth and ninth aspects of the present invention, the automatic control device senses sound propagating in the air to perform electrical A microphone that outputs a signal, and a function of suppressing the vibrating force of the eccentric weight or the cylinder means so that the noise level of the acoustic signal input from the microphone does not exceed a predetermined limit value. It is characterized by having. According to the apparatus of the tenth aspect described above, the noise pollution regulation can be cleared while the vibration pollution regulation is cleared. The microphone according to the present invention is particularly adapted to sense airborne sound, so that the sound generated by the pile rubbing against the ground and the sound generated by the crushing of the stratum by the pile are hardly detected. Instead, it exclusively detects the noise generated by ground equipment,
Sound that is close to the sensation of a person on the ground is captured, and practical and effective noise control can be performed based on the sound.

According to an eleventh aspect of the present invention, in addition to the constituent features of the tenth aspect of the present invention, the exciter includes a power unit having an engine as a power source. The vibration pickup is mounted on the casing of the power unit so as to be in contact with the ground, and the microphone attenuates sound transmitted from the engine and propagates through the air from the exciter. In order not to attenuate the incoming sound as much as possible,
It is mounted directly or indirectly on the casing of the power unit in a state "semi-enclosed by the sound insulating material".

According to the eleventh aspect of the present invention described above, it is possible to eliminate the need for the worker involved in the pile driving work to install, withdraw, or store the vibration pickup and the microphone. The invention of claim 11 was born from the actual situation of the construction work site, and in view of the trend of the industry in which "skilled technicians having advanced knowledge and site management ability" became rare, simple labor Created so that pollution prevention work can be made possible by people
This is a very practical invention. From a construction machine manufacturer's point of view, this can stimulate demand by reducing the administrative burden on the user, and can contribute to the development of the vibratory pile driver industry. Furthermore, as described above, by alleviating the burden of on-site management, there are many ways to contribute to the promotion of exports to developing countries where the industry technical level is not high.

[0021]

FIG. 1 is a schematic vertical sectional view showing one embodiment of a pollution-free pile driving method using a pollution-free pile driving device according to the present invention. However, since it is drawn as a principle diagram, it is not necessarily a realistic projection diagram. Exciter 2
Holds the upper end of the pile 1. The vibration exciter 2 of this embodiment includes a pair of eccentric weights 2a, and is rotated by a drive motor 2b. The pair of eccentric weights rotate in opposite directions in synchronization with each other, and the phase difference thereof is adjusted to be increased or decreased by the vibration controller 2c. Considering one eccentric weight,
The eccentric moment is constant and invariable, but when the two eccentric weights rotate synchronously, the total eccentric moment of the two eccentric moments generates an exciting force, and the two rotational phase differences are If it changes, the above total eccentric moment changes.
As a result, the excitation force changes, and as a result, the amplitude of the vibration changes. In this way, even when the motor is rotating at the same rotational speed, the effective eccentric moment is changed, and the vibrating force is increased or decreased. Although an eccentric weight type vibrator having such a function is known, in the present invention, as described above, it is an important component to change the vibration intensity while keeping the rotation speed constant. . In other words, a function that can adjust the intensity of vibration independently of the frequency of vibration is required. However, the regulation value of the vibration pollution may be represented by an amplitude, a vibration acceleration (gal), or a decibel (dB) under an assumed condition. In other words, independent of frequency,
An eccentric weight type vibration exciter of a type capable of adjusting a physical quantity representing the intensity of vibration is used.

In this type of eccentric weight type vibrator, the frequency can be adjusted independently of the physical quantity representing the vibration intensity. The details of this function are as follows. Effective rotational moment (same as total eccentric moment)
If the rotational speed of the eccentric weight is changed without changing the value, the intensity of the vibration also changes accordingly. However, it is easily possible to adjust the effective rotational moment and not change the strength of the vibration. In the present invention, the frequency is controlled independently with respect to (the physical quantity representing) the vibration intensity, including the case where the frequency is changed while compensating for the vibration intensity to be constant. .

The power unit 6 is installed at a position away from the point where the pile 1 is set. The power unit includes an engine as a power source, and supplies motive energy to the exciter 2 via a cable or a hose 7. The vibration pickup 8 is installed near the ground away from the pile driving point and in contact with the ground. Here, "contact with the ground" means that the sensor element is in a state where vibration of the ground can be detected, and it is not always necessary to make contact with the appearance. Further, a microphone 9 is installed in the vicinity thereof so as to capture sound propagating in the air, and an output signal of the microphone 9 and an output signal of the vibration pickup 8 are input to the control device 10.

When the pile 1 is erected on the ground and starts to penetrate into the ground, the generated vibration propagates through the ground as indicated by an arrow a, reaches the vibration pickup 8 and is detected. As the penetration depth of the pile 1 increases, vibration is generated from a wide range as indicated by arrows b, c, and d. FIG. 1 shows a to d
However, the vibration is generated from all the points of the area L where the pile 1 is in contact with the ground 5 and propagates in all directions. -D schematically illustrate that some of them reach the vibration pickup 8. The noise generated by the exciter 2 travels through the air as shown by the arrow e and reaches the microphone 9. Background noise (arrow g) also enters this microphone 9. Here, the constructor of the vibration pile driving work,
It is required that the total amount of not only the noise generated by itself but also the background noise be below the noise pollution regulation value. Therefore, in the present embodiment, the microphone 9 does not distinguish between the sound (arrow e) from the exciter 2 and the background noise (arrow g).
And outputs the output signal to the control device 10. The output signal of the vibration pickup 8 and the microphone 9
The control device 10 which has received the output signal of (1) performs the control calculation as described below, gives a command signal f to the vibration controller 2c of the exciter 2, and outputs the total eccentricity of the eccentric weight 2a. Increase or decrease the moment.

In this embodiment, the main purpose of the control is vibration, and the sub purpose is noise. The reason is as follows. That is, with respect to the noise generated from the vibration exciter 2, there are a method of covering the vibration exciter with a soundproof cover and a method of providing a soundproof wall around the pile driving section, but the pile and the ground come into contact with each other. This is because, as a practical problem, it is impossible to cut off the middle of the propagation path of a vibration generated from a certain point, and it is only effective to control the source of the vibration.

In the pile driving work, a physical quantity representing an allowable vibration intensity is given in advance. For example, in the case of a hospital, the seismic intensity level in seismic engineering is in the “insensitive” stage (0
8 gal or less) is one standard. The frequency of the vibration generated by the vibration exciter 2 is determined by the rotation speed of the drive motor 2b, and the frequency does not change even if only the total eccentric moment is changed. When the total eccentric moment is increased or decreased, the intensity of the vibration changes proportionally. Therefore, the control device 10 outputs the command signal f and activates the vibration controller 2c, so that the physical quantity representing the vibration intensity does not exceed a predetermined value (vibration pollution regulation value). Control the eccentric moment. The control of the above total eccentric moment
The control is performed so that the physical quantity representing the vibration intensity does not exceed the vibration pollution regulation value, and as close as possible to the vibration pollution regulation value within a range not exceeding the vibration pollution regulation value. Thereby, the working efficiency can be improved as much as possible without generating the vibration pollution and within the range where the vibration pollution does not occur.

The embodiment described above with reference to FIG. 1 is an example in which the present invention is applied to an eccentric weight exciter and is improved. Next, referring to FIG. An embodiment in which the present invention is applied to a vibration exciter of another name (also called a piston type or a cylinder type) will be described. The hydraulic exciter does not include the eccentric weight 2a or the drive motor 2b, but instead has a reaction force weight and hydraulic cylinder means (both not shown).
It has. The hydraulic cylinder means is not limited to hydraulic pressure, but may be any hydraulic cylinder means. As mentioned above,
When FIG. 1 is viewed as a hydraulic exciter, the power unit 6
Is provided with an engine-driven hydraulic pump (not shown), and a member denoted by reference numeral 7 in the drawing is a hydraulic hose,
The vibration controller 2c is composed of a servo valve. The servo valve controls the hydraulic cylinder means to perform a reciprocating operation to generate vibration. In this case, the vibration frequency and the vibration intensity are determined by the command signal f of the control device 10. In this embodiment, the frequency of the generated vibration is controlled independently of each other by the number of switching operations of the servo valve, and the strength of the vibration is controlled by (oil pressure × flow rate). If the intensity and frequency of vibration are controlled independently of each other, the vibration emission regulation value should not be exceeded, and the vibration emission regulation value should not be exceeded, as in the case of the eccentric weight type vibrator described above. By controlling the physical quantity representing the strength of the vibration so as to be close to each other, the same effect as in the eccentric weight type vibrator can be obtained.

(See FIG. 1.) In both the eccentric weight type vibration exciter and the hydraulic type vibration exciter, the control of the physical quantity representing the vibration intensity is as follows. Do not exceed the regulation value "as the first condition without exception. Further, as described above, under the first condition, the control is performed so as to be as close as possible to the above-mentioned vibration pollution regulation value. The constraint of not occurring is added. The control corresponding to the noise pollution regulation is performed by the control device 10 so as to limit the vibration output of the vibration exciter 2 so that the sound level sensed by the microphone 9 is within the noise pollution regulation value.

(A) Even if the vibration generated by the vibration exciter 2 is the same, the intensity of the vibration reaching the vibration pickup 8 often changes significantly due to the resonance phenomenon due to the difference in the stratum structure. (Rather, it usually changes.) (B) Even if the intensity of the vibration reaching the vibration pickup 8 is the same, the vibration generated in a building (not shown) near the vibration pickup significantly changes due to the resonance phenomenon. Therefore, the problem of resonance cannot be ignored in pile driving. Similarly, even if it is caused by the resonance phenomenon, the above-mentioned (a) and (b) are essentially different problems, and the measures for this must be different. Hereinafter, description will be made sequentially. In order to deal with the problem until the vibration of the ground reaches the vibration pickup 8, prior to hitting a plurality of piles or a large number of piles, or prior to moving the pile driving point, a test is performed as described below. Pile one pile in In this case, “experimentally” means that data to be used is being collected, and it is not enough to use extra piles.

The test casting is performed continuously or stepwise while changing the frequency of the vibration generated by the vibrator, and the intensity (for example, amplitude) of the vibration reaching the vibration pickup 8 is detected and recorded. I do. Then, even if the amplitude of the vibration generated by the vibration exciter 2 is constant, a frequency at which the amplitude of the vibration detected by the vibration pickup 8 shows a peak value is found. There are cases where the peaks are sharp and unclear,
Since the ground and underground structures generally have a natural frequency, a resonance frequency or a resonance frequency range (also called a resonance frequency band) is found almost without exception. In full-scale driving after the test driving, the driving is performed while avoiding the above-described resonance frequency or resonance frequency band. In this case, the resonance frequency of the crane that holds the exciter must be avoided, but the resonance frequency of the crane boom is usually known. It is desirable to avoid this.

In the case where there is a building or the like which is contra-indicated by vibrations near the pile driving site, the vibration must not be transmitted to people or objects in the building such as a hospital or a museum. For example, there is a case where the building itself has a risk of collapse such as a brick building. In such a case, the construction designer naturally knows such circumstances, or issues a construction specification after conducting an investigation.
Also, the generated vibration frequency of the exciter may be set so as to avoid a frequency that is a fraction of the integer. The reason for avoiding the frequency of the integer ratio also includes preventing resonance due to harmonics of the frequency generated by the exciter. As described with reference to FIG. 3 described above, when driving a pile, it is customary that a plurality of strata exist between the driving depths. If the stratum and the geology are different, the vibration characteristics are also different.

Considering an extremely simplified example (see FIG. 3C), if the magnitude of the vibration generated by the vibration exciter 2 is constant, the gravel layer 5d in which the lower end of the pile 1 is solidified is When it reaches, the vibration (arrow d in FIG. 1) propagating through the ground increases. Since this vibration increase is detected by the vibration pickup 8, the vibration output of the vibration exciter 2 may be controlled so that the detected vibration is slightly smaller than the regulation value.

In practice, as shown in FIG. 3, the vibration (arrow a) or the vibration (arrow a) shown in FIG. 1 passes through the various formations 5a, 5b, 5c and reaches the formation 5d serving as the support layer. Since the arrow d) changes, the optimum exciter amplitude can be obtained as the penetration depth of the pile increases. As described above, the optimum amplitude (meaning the optimum vibration force) as a function of the penetration depth of the pile is experimentally determined. Since the vibration frequency to be avoided has already been determined, the above-mentioned test should be performed according to the penetration depth while driving the pile at a frequency other than the vibration frequency to be avoided during full-scale pile driving work. The output of the exciter is controlled so as to have the optimal amplitude (optimal excitation force) (a function of the penetration depth) determined in a specific manner. This method is suitable when the stratum structure consists of parallel strata. The “pile penetration depth” may be measured indirectly. That is, the physical quantity (for example, the extension length of the clean rope 4) that uniquely corresponds to the penetration depth of the pile can be changed.

When the other piles are driven in a fixed pattern according to the data obtained by one test driving, the control of the vibrating force of the vibrator is simple. In this case, the constant pattern is stored in the control device 10 and the appropriate vibrating force as a function of the penetration depth for each pile (without consideration of the penetration speed as in the prior art is unnecessary) is controlled. Accordingly, the non-polluting pile driving work can be performed for all the piles, and the maximum work efficiency can be exhibited for all the piles within a range that does not violate the pollution control. When a large number of piles are driven in a fixed pattern as described above, it is also useful to use the vibration pickup 8 and / or the microphone 9 in combination and to monitor to confirm that the pollution control does not conflict. When the ground structure is complicated and the stratum is not parallel, for each of a plurality of piles or a large number of piles to be driven in one or more construction sections, a vibration pickup is applied from the start to the end of the pile. Control to make the physical quantity representing the intensity of vibration detected by 8 smaller than the vibration pollution regulation value as close as possible to the regulation value, and / or control to make the sound detected by the microphone 9 within the noise pollution regulation value. Must be carried out for each pile.

As described above, data is recorded while changing the frequency of the vibration generated by the exciter, a test pile is driven, the resonance frequency of the ground or structure is obtained, and the obtained resonance frequency is obtained. It is effective to avoid serious accidents and perform a full-scale driving to prevent unexpected problems due to resonance.However, it takes a certain amount of time to record data by driving test piles. And cost, it is uneconomical if the number of castings is small. Therefore, the following expedient utilizing frequency analysis is also very useful depending on the working conditions. The control device 10 has a function of analyzing the frequency of the vibration waveform input from the vibration pickup 8. Various vibrations represented by arrows a to d arrive at the vibration pickup 8, and the vibration pickup 8 detects a composite vibration in which various vibrations are synthesized. If a skilled engineer looks at the result of analyzing the detected complex vibration with the control device 10, the outline of the vibration engineering characteristics of the ground and the building can be determined. Therefore, an appropriate (safe and efficient) vibration frequency for construction can be determined based on the above determination. For example, if a peak appears at a frequency that does not appear in normal work in the frequency analysis data when a pile is driven near a dam, it is assumed that the frequency is the natural frequency of the dam. Is done. Such a determination can be easily and immediately made by a person who has performed a pile driving operation under various operation conditions.

FIG. 1 is a principle explanatory diagram schematically drawn as described above.
Although the vibration pickup 8 and the microphone 9 are illustrated as being separated from each other, in actuality with such a structure,
At the time of stakeout work, the vibration pickup 8 and the microphone 9 must be installed and wired, and after the stakeout work, it must be withdrawn and stored. In addition, there is no danger of being damaged due to a collision of an external obstacle during the operation. FIG.
Indicates the relative positional relationship among the vibration pickup, the microphone, the automatic control device, and the power unit schematically illustrated in FIG. 1 described above, and also indicates the transmission of the output signals of the sensors and the like. FIG. 3 is a cross-sectional view illustrating an attached member of the microphone. Vibration pickup 8
Is the casing of the power unit 6 (including the frame)
And is brought into contact with the ground 5, and the output signal is input to the pollution-free operation unit 11 a in the automatic control device 11. The microphone 9 is installed directly or indirectly on the casing of the power unit 6, and is partially surrounded by a soundproof material 12 so as to cut off sound from the rotating device 6b. The sound insulating material 12
Is configured so that sound from outside the power unit is not attenuated as much as possible, and sound from the rotating device 6b is attenuated as much as possible. According to the structure shown in FIG. 2, advanced technical operations such as installation, withdrawal, and storage of the vibration pickup 8 and the microphone 9 are not required, and therefore, for developing countries in which inexperienced workers must be used. It is suitable. Also, even when migrant workers from developing countries are employed in Japan, no special teacher training is required, and there is no risk of troubles such as forgetting to connect the vibration pickup or microphone, incorrect connection, or misplacement. .

[0037]

As described above, according to the embodiment of the present invention, the structure and function thereof are clarified. According to the invention method of claim 1, the frequency of the vibration generated by the exciter is equal to the frequency of the eccentric weight. It matches the rotation speed. Therefore, while adjusting the effective rotational moment of the eccentric weight while rotating the eccentric weight at the same rotation speed, while maintaining the frequency of the generated vibration constant,
Its amplitude can be varied. Regulation of vibration intensity to prevent pollution may be indicated by amplitude, vibration acceleration, or decibel, but in any case, the effective eccentric moment Can be varied to change the physical quantity representing the vibration intensity independently of the vibration frequency. Thus, it is extremely important in practical use to be able to change the vibration frequency and the vibration intensity independently of each other. The reason is that, for example, when the vibration intensity is adjusted by changing the rotation speed to change the vibration acceleration, if the amplitude is changed to the desired strength, the frequency changes involuntarily. As a result, the frequency of the vibration generated by the exciter resonates with the natural frequency of the ground to amplify the vibration pollution, or resonates with the boom of the crane that holds the exciter, and This is because there is a great risk of damaging the device. According to the construction method of the present invention, it is possible not only to suppress the intensity of vibration without fear of inducing an unexpected serious trouble, to not exceed the regulation value of pollution, but also to use one pile. Even when penetrating into the ground, the stratum in contact with the pile changes as the penetration progresses, so that no pollution occurs in response to the vibration engineering characteristics of the partner stratum that is changing every moment. The exciter can be controlled so as to generate as strong a vibration as possible within a limit (a pollution regulation value). This allows
It is possible to improve the efficiency of vibration pile driving work while preventing vibration and noise pollution. The excellent practical effects described above are based on the conventional technology of simply detecting vibration / noise and controlling the vibrating force of the vibrator, and proceeding further with the frequency of vibration (rotational speed of the eccentric weight). This can be achieved for the first time by individually controlling the amplitude (effective rotational moment of the eccentric weight).

According to the construction method of the second aspect, the frequency of the vibration generated by the vibration exciter is determined by the expansion and contraction of the cylinder or the number of reciprocations of the piston. The amplitude of the generated vibration is determined by the amount of supplied energy per one stroke (pressure × flow rate). Therefore, the amplitude can be changed while keeping the vibration frequency constant. Regulation of vibration intensity to prevent pollution is sometimes expressed by amplitude, sometimes by vibration acceleration, and sometimes by decibels. On the other hand, it is possible to independently increase or decrease the physical quantity representing the vibration intensity. Thus, it is extremely important in practice to be able to change the vibration frequency and the vibration intensity independently of each other. The reason is that, for example, when the vibration intensity is adjusted by changing the rotation speed to change the vibration acceleration, if the amplitude is changed to the desired strength, the frequency changes involuntarily. As a result, the frequency of the vibration generated by the exciter resonates with the natural frequency of the ground to amplify the vibration pollution, or resonates with the clean boom that suspends the exciter, and This is because there is a great risk of damaging the device. According to the construction method of the present invention, it is possible not only to suppress the intensity of vibration without fear of inducing an unexpected serious trouble, to not exceed the regulation value of pollution, but also to use one pile. Even when penetrating into the ground, the stratum in contact with the pile changes as the penetration progresses, so that no pollution occurs in response to the vibration engineering characteristics of the partner stratum that is changing every moment. The exciter can be controlled so as to generate as strong a vibration as possible within a limit (a pollution regulation value). As a result, it is possible to improve the efficiency of the pile driving work while preventing vibration and noise pollution. The excellent practical effects described above are based on the conventional technology of simply detecting vibration and noise and controlling the vibrating force of the vibration exciter, and by further controlling the frequency and amplitude of vibration separately. This is the first time I played.

According to the third aspect of the present invention, the vibration which occurs along with the penetration of the pile and propagates through the ground to the regulation target point within the limit value is suppressed, and is mainly generated from the vibration exciter. The total amount of the construction noise and the background noise not caused by the pile driving work within the noise limit value, and within the conditions of suppressing each of the vibration and noise within the limit value as described above, It is possible to improve the efficiency of pile driving work to the maximum value. That is, when the invention method of claim 3 is applied, the unique effect obtained by individually controlling the vibration frequency and the amplitude of the exciter which is the ground vibration source in claim 1 or 2 is obtained. Without impairing, noise regulations can be cleared, and a decrease in work efficiency can be minimized (work efficiency can be improved as much as possible).

According to the construction method of the fourth aspect of the present invention, even when one pile is vibrated, the other stratum changes as the one pile penetrates into the ground. Since the resonance frequency is avoided by experimentally grasping the change in the resonance characteristics due to the geological change every moment, it is possible to prevent the occurrence of troubles due to resonance when driving piles into vibration beforehand and surely. it can. As described above, the reason for avoiding the resonance frequency and performing the practical pile driving operation is that the amplitude and the vibration frequency are controlled independently of each other with respect to the vibration control of the exciter. It can be established on the premise of the configuration described above. The reason is that when the vibration frequency generated by the vibration exciter is increased or decreased in order to avoid the resonance frequency, the pile driving work is extremely difficult if the amplitude is involuntarily changed.

According to the construction method of the fifth aspect, it is possible to prevent unexpected damage to a building or a structure adjacent to the pile driving point. In the fourth aspect of the present invention, the ground vibration is prevented from being unnecessarily amplified harmlessly due to the resonance of a natural object. In contrast, the fifth aspect of the present invention mainly comprises an artificial structure (for example, Prevents houses, bridge dyes, pillars, retaining walls, etc.) from being damaged by resonance. Furthermore, preventing the resonance of the structure not only prevents the damage of the structure itself, but also indirectly prevents the harm of vibration to the people in the structure and the easily damaged items installed therein. As a practical matter, the practical value of indirectly protecting people and easily damaged items as described above is great. For example, when a pile driving work is performed near a hospital, even if the vibration of the ground supporting the hospital building is insensitive vibration (acceleration 0.8 gal (about 55 dB) or less), the building resonates. Patients lying in the room receive significant irritation. The fifth aspect of the present invention prevents such an unexpected situation completely and completely, and makes it possible to perform pollution-free pile driving.

According to the invention method of claim 6, the vibration engineering characteristics of the geological structure in the area are grasped by using the "optimum amplitude and / or the optimal frequency" as a parameter by driving a test pile to perform a test. For most piles other than piles, precise control for each pile can be omitted, and the piles can be driven without pollution, thus reducing the man-hours required for construction work. The invention method of claim 6 is desirably applied when the stratum is substantially parallel. If, after predicting that the stratum structure is simple and parallel and applying the present claim 6 and starting pile driving work, the measured value by the vibration pickup is likely to exceed the vibration limit value, the present claim is made. It is also possible to easily cancel the application of the item 6 and switch to the control of each one.

According to the construction method of the present invention, even if the stratum structure is complicated, the construction section is vast, or a plurality of construction sections are dispersed, the construction method is not violated by the pollution control and the pile driving is performed. Vibration pile driving work can be performed while minimizing the decrease in work efficiency. The construction method according to claim 7 can be applied to a case in which a plurality of piles are simultaneously driven in parallel by arranging a vibration exciter for each of the plurality of construction sections, and The present invention can also be applied to a case where the exciter is moved and a plurality of construction sections are sequentially traversed while the excavator is driven one by one.

According to the invention, the frequency of the generated vibration can be controlled by adjusting the rotation speed of the eccentric weight, and the total eccentric moment of the eccentric weight can be adjusted. Since the amplitude of the generated vibration can be controlled, and the frequency and the amplitude of the generated vibration can be individually controlled as described above, for one, the amplitude can be controlled without changing the frequency. The amplitude can be suppressed to within the regulation value of vibration pollution. For the same reason, the regulation value of vibration pollution can be cleared whether the regulation value is given by vibration acceleration or decibel. On the other hand, the frequency can be changed while keeping the amplitude or the vibration acceleration at a desired value. Since the frequency can be arbitrarily controlled in this way, it is possible to generate a vibration of a desired strength while avoiding the resonance frequency of the ground,
It is also possible to generate vibration of a desired strength while avoiding the resonance frequency of the building. Applying the present claim, as an overall effect of the above-described operation, the vibration pollution regulation is cleared corresponding to various geological structures, and the work efficiency is maximized within a range that does not conflict with the vibration pollution regulation. Can be improved.

According to the ninth aspect of the present invention, a vibration pile driving machine using a cylinder means (so-called piston type) is improved to prevent vibration pollution and noise pollution, and to provide a highly efficient device within a possible range. Can perform work. In particular, because it has a frequency analysis function, it can operate at the maximum amplitude within the possible range while suppressing vibration in response to the vibration engineering characteristics of the ground, so that pollution regulations can be cleared and work efficiency can be improved. It is possible to achieve both improvement and improvement. The vibration characteristics of the ground are not invariable. The area of the stratum in contact with the pile increases as the pile penetrates, and the stratum crushed and consolidated by the lower end of the pile changes. Therefore, the device according to the present invention corresponds to the “geologically related to the pile due to vibration engineering” which changes every moment, within a range that does not violate the vibration pollution regulation and the noise pollution regulation in real time. It is possible to carry out the most efficient vibration pile driving work.

According to the tenth aspect of the present invention, it is possible to clear the noise pollution regulation while clearing the vibration pollution regulation. The microphone according to the present invention is particularly adapted to sense airborne sound, so that the sound generated by the pile rubbing against the ground and the sound generated by the crushing of the stratum by the pile are hardly detected. Instead, since the noise generated by the ground equipment is sensed exclusively, it is possible to capture sound close to the sensation of a person on the ground and to perform practical and effective noise control based on the sound.

According to the eleventh aspect of the present invention, it is possible to eliminate the need for a worker involved in the pile driving work to install, withdraw, or store the vibration pickup and the microphone. The invention of claim 11 was born from the actual situation of the construction work site, and in view of the trend of the industry in which "skilled technicians having advanced knowledge and site management ability" became rare, simple labor It is an extremely practical invention created by a person to make pollution prevention work possible.

From the viewpoint of a construction machine maker, the demand can be stimulated by reducing the administrative burden on the user, which can contribute to the development of the vibratory pile driving machine industry. Furthermore, as described above, by alleviating the burden of on-site management, there are many ways to contribute to the promotion of exports to developing countries where the industry technical level is not high.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing one embodiment of a pollution-free pile driving method using a pollution-free pile driving device according to the present invention. However, since it is drawn as a principle diagram, it is not necessarily a realistic projection diagram.

FIG. 2 shows a relative positional relationship among a vibration pickup, a microphone, an automatic control device, and a power unit schematically drawn in FIG. 1 described above, and transmits an output signal of sensors and the like. FIG. 3 is a cross-sectional view illustrating an arrow and an attached member of the microphone.

FIG. 3 is a schematic vertical cross-sectional view of a vibrating pile driving work shown to explain aspects of occurrence of vibration pollution. FIG. 3 (A) shows the lower end of the pile at the initial stage of driving, within the clay layer of the surface layer. (B) depicts a state in which the lower end of the pile at the middle of the driving is in the silt layer, and (C) shows a state in which the lower end of the pile at the end of the driving penetrates the gravel layer, which is the main support layer. The state and the crane boom are depicted.

FIG. 4 is a view for explaining a state in which the vibration of the pile changes depending on the stratum, and FIG. 4A is a vibration waveform chart in a state in which the lower end of the pile faces relatively soft ground; (B) is a vibration waveform chart in a state where the lower end of the pile faces the relatively hard ground (gravel layer).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pile, 2 ... Exciter, 2a ... Eccentric weight, 2b ... Drive motor, 2c ... Vibration controller, 3 ... Crane boom, 4 ... Crane rope, 5 ... Ground, 5a ... Clay layer, 5b ... Silt layer 5c: sand layer, 5d: gravel layer, 6: power unit, 6
a: operation panel, 6b: rotating device, 7: cable or hose, 8: vibration pickup, 9: microphone, 10
... Control device, 11 ... Automatic control device, 11a ... Non-polluting operation unit, 12 ... Sound insulation material.

Claims (11)

[Claims] 1. A pile driving method in which an exciter of a type that generates vibration by rotating an eccentric weight is attached to a pile, and the pile is vibrated in the longitudinal direction to penetrate the ground. While rotating the eccentric weight, while using an exciter having a structure capable of controlling the excitation force by changing the effective rotational moment of the eccentric weight, separated from the pile driving point, and A vibration pickup is installed in contact with the ground, a vibration is applied to the pile by operating the exciter, and the pile is penetrated into the ground, and the vibration propagating to the vibration pickup is measured, The physical quantity representing the intensity of the measured vibration is adjusted so as not to exceed the limit value specified in advance, and within the range of the limit value, so as to approach the limit value as much as possible, Control the excitation force of the exciter Characterized in that, pollution-free piling method. 2. A pile is provided with a vibrator that generates vibration by repeatedly expanding and contracting a cylinder or reciprocating a piston, and penetrates the ground by giving a vibration in the longitudinal direction to the pile. In a pile driving method, a hydraulic exciter having a structure capable of independently controlling the amplitude and frequency of vibration by changing a hydrodynamic value of an energy source supplied to the cylinder or the piston is used. A vibration pickup is installed by separating from the setting point and contacting with the ground, and activating the exciter to apply vibration to the pile and causing the pile to penetrate into the ground, Vibration that propagates up to the limit value is measured so that the physical quantity representing the measured vibration intensity does not exceed the pre-specified limit value and is within the limit value. Adjusting the energy source supplied to the cylinder or piston so as not to change the frequency of the vibration generated by the exciter, and to control the amplitude independently of the penetration speed of the pile, Non-polluting pile driving method. 3. A microphone is installed at a distance from a stake placement point to measure a level of noise propagating to the microphone, and a value of the noise level measured by the microphone is specified in advance. Suppressing the vibrating force of the vibration exciter so as not to exceed the noise limit value, and within the range where the value of the measured noise level does not exceed the noise limit value, a physical quantity representing the vibration intensity is calculated. The non-polluting pile driving method according to claim 1 or 2, wherein the pile is driven close to the vibration limit value. 4. The vibration exciter uses a vibration exciter capable of increasing and decreasing the frequency of vibration, and operates the vibration exciter to cause the pile to penetrate into the ground, while testing the vibration frequency. In addition, the vibration is measured by the vibration pickup while changing continuously or stepwise, and a physical range representing the measured vibration intensity is obtained in a frequency range in which the resonance of the ground or the structure increases, and the above resonance frequency range is obtained. The non-polluting pile driving method according to any one of claims 1 to 3, wherein the vibratory pile driving operation is performed by operating the exciter while avoiding the vibration. 5. A resonance frequency of one or a plurality of buildings or structures adjacent to a piling site, and the resonance frequency obtained by the survey and / or the resonance frequency obtained by the survey are obtained. 5. The non-polluting pile driving according to any one of claims 1 to 4, wherein the vibrating pile driving operation is performed by operating the vibration exciter while avoiding a frequency that is a fraction of the resonance frequency. Construction method. 6. When one or more piles are driven in an area where there is no significant difference in geological structure, one or more piles are experimentally placed in the area. Driving according to the method of claim 2 and determining the optimum amplitude and / or frequency as a function of the penetration depth of the pile or as a function of a numerical value which uniquely corresponds to the penetration depth, For piles other than the set pile, the exciter is operated at the above-mentioned optimum amplitude and / or optimum frequency to drive the pile, or for piles other than the test pile, the above-mentioned vibration pickup is used. When the vibration excavator is operated at the optimum amplitude and / or the optimum frequency to perform the driving while performing the actual measurement of the vibration by the vibration pickup, and the measured value by the vibration pickup reaches the predetermined limit value, Limit value Which comprises suppressing a vibratory force of the exciter so as not to exceed, pollution-free piling construction method according to either one of claims 3 to 5. 7. When a plurality of piles or a plurality of piles are driven into one or a plurality of construction sections by an exciter, actual measurement of vibration by the vibration pickup and / or noise by the microphone are performed for each pile. Perform the casting work while actually measuring the level, and make sure that the vibration and / or noise level does not exceed the limit value in response to changes in the generation and propagation of vibration and noise due to changes in the penetration depth of the pile. The pollution-free pile driving method according to any one of claims 3 to 5, further comprising controlling a vibrating force of a vibrator. 8. An at least one pair of eccentric weights, a drive motor capable of adjusting a rotation speed for rotating the eccentric weights, and changing a rotational phase difference between the at least one pair of eccentric weights. Means for adjusting a total eccentric moment, in a pile driving device having a vibration exciter, comprising: a vibration pickup capable of measuring ground vibration; and an output signal of the vibration pickup being input, and a total of the eccentric weight. An eccentric moment and an automatic control device for controlling the rotation speed thereof are provided. The automatic control device has a function of analyzing the frequency of the input vibration, and controls the intensity of the measured vibration. The value of the physical quantity representing the value is equal to or less than a predetermined value, and the value of the physical quantity representing the vibration intensity of a predetermined frequency or frequency range is a predetermined value different from the above. As it will be lower, characterized in that it has a function of automatically controlling the overall eccentric moment and / or rotational speed, no pollution piling device. 9. A pile driving device having a vibration exciter comprising a cylinder means for generating vibration and a servo valve for adjusting fluid energy supplied to the cylinder means, wherein a vibration pickup capable of measuring ground vibration is provided. And an automatic control device that receives the output signal of the vibration pickup and controls the operation of the cylinder means via the servo valve. The automatic control device performs frequency analysis on the input vibration. The value of the physical quantity representing the measured vibration intensity is equal to or less than a predetermined value, and the value of the physical quantity representing the vibration intensity at a predetermined frequency or frequency range. However, a function of controlling the vibrating force of the vibrator via the servo valve so as to be equal to or less than a predetermined value different from the above, regardless of the penetration speed of the pile. Characterized in that it is pollution-free piling device. 10. The automatic control device according to claim 1, further comprising: a microphone that senses sound propagating in the air and outputs an electric signal. The noise level of the sound signal input from the microphone is determined in advance. The non-polluting pile driver according to claim 8 or 9, characterized in that it has a function of suppressing the oscillating force of the eccentric weight or cylinder means so as not to exceed a given limit value. apparatus. 11. The vibration exciter includes a power unit having an engine as a power source, wherein the vibration pickup is mounted on a casing of the power unit and comes into contact with the ground. The microphone is a power unit that is `` attenuated sound transmitted from the engine and is half-enclosed by a sound insulating material so as to minimize the sound transmitted from the exciter through the air. '' The non-polluting pile driving device according to claim 10, wherein the non-polluting pile driving device is directly or indirectly attached to the casing.