JP2006519327A - Method and apparatus for driving an element - Google Patents

Abstract

  Method and apparatus for driving by simultaneously striking and vibrating a mass of material, in particular an element in contact with or surrounded by a formation, said element being in surface contact with that for compressing the mass of material It consists of a stamping plate or an elongated object such as a pile or pile that is driven or pulled axially into the mass of material. An energy source, such as a striking hammer or vibrator, applies an impact directly or indirectly to drive the stamping plate toward or away from the mass of material. The vibration device is adjustable to the desired vibration frequency that is close to the natural frequency for the element, the area of the mass of material engaged by the element, and the system defined by the vibration device. When driving an elongate element into a mass of material, the resonant frequency can be lowered to the natural frequency or above it to compress the mass of material around the elongate element in the final drive stage of the elongate element.

Description

  The present invention relates to a method for driving an element in contact with a mass of material such as a formation, the element comprising a stamping plate in surface contact with the mass of material to compress the material or It includes a pile driven into the mass of material of the type described in the introduction of paragraph 1, or an elongated object such as a pile or compression tool.

  The invention also relates to a corresponding device of the type described in the preamble of claim 11.

  One identical facility is known for applying both striking and vibration forces to an area of ground to compress the volume of soil engaged. For example, Dutch patent application no. 7415157 discloses a stamping plate that contacts the ground and receives high energy thrust from a hammer. A ring-shaped vibrating plate is in contact with the ground around the stamping plate and includes an eccentric weight that is rotationally driven and supports an active vibrator that supports an inertial mass via a spring device.

  EP 0299118 A1 discloses a deformation in which a hammer hits down to come into direct contact with the ground as if it were controlled on a vertical column with the lower end lowered into the ground and an active vibrator at the upper end.

  When building a foundation, it may be necessary to improve the geotechnical properties of the formation, or to reinforce the formation by laying piles or piles. The best method of laying depends on the nature of the soil and the load caused by the planned structure. In certain soil layers, for example clay soils such as clay, optimal penetration of the object is achieved by a short impact (striking hammer). In other conditions, such as non-viscous soils such as sand and gravel, pile and pile vibration drive or vibrator soil compression is the most efficient method. It is desirable to generate both blow and vibration using the same equipment. There is currently no such facility. Directly active active vibrators are expensive and have a short life due to bearing failure due to eccentric weights. Striking hammers have a limited effect, especially on non-viscous soils.

  It is therefore an object of the present invention to strike an element by striking or vibrating in an efficient and thus power saving manner to drive an element into the material or to pull the element out of the material and to compress the material. Is to make available the technology that is driven.

  Another object of the invention is that the resonant frequency is such that, for example, the resonant frequency substantially corresponds to or is at a suitable distance from the natural frequency of the element and the material area engaged thereby. It is to provide a vibration device that is adjustable.

  These objects are achieved in whole or in part by the present invention.

  The present invention is defined in claim 1.

  The present invention is defined in claim 11.

  Specific examples of the invention are defined in the dependent claims.

  The present invention can be advantageously used to compress formations such as non-viscous materials with the help of a stamping plate that lies on the ground and is struck by a hammer or vibrator. Alternatively, the present invention can be used to drive a pile or pile into the formation, the hammer hitting the pile or pile, and the pile or pile comprising a passive vibration device. By dynamic adjustment using a passive vibration device (mass / spring system attached to the object), the impacted object (plate or elongate element) can be set to a strong and extended vibration motion. The added drive energy is thus utilized in an optimal manner. In order to achieve effective penetration, it is preferred that the passive vibrator has a resonant vibration frequency that corresponds to the natural frequency of the pile / pile. When compressing, it is preferred that the resonant vibration frequency of the vibration device be close to the natural vibration frequency of the entire vibration system. The entire vibration system includes an engaged mass and a compression device (plate, pile or compression tool). The elongate object can also be in the form of a compression device, in which case it can be used to set the soil.

  The vibration device utilizes a resonance effect that reinforces the applied drive energy and extends the vibration duration and gives the drive a very long useful life. In accordance with the present invention, the passive energy transferred from the active energy source towards the plate or elongated element is reused and amplified.

  The spring device naturally constitutes part of the mass of the vibration device. The spring members of the spring device can be designed in coil springs, flexure springs, torsion springs, or other suitable and known shapes for generating the described motion of mass. Further, the spring can comprise a suitable link arm or mechanism for generating the desired motion described.

  The energy for setting the vibration device in vibration motion can be supplied in various ways, for example by applying a hammer impact to the element or to the mass supported by the vibration device or by a vibrator connected to the mass of the vibration device Can do.

  The invention is not limited to applications in the field of foundation construction, i.e. compression and driving or pulling piles or piles into the ground, but in principle all types of material compression and all types of rigid objects It can be used to drive into a penetrable material.

  One of the important benefits of the present invention is that the technique according to the present invention can be combined with conventional equipment for soil compaction and pile / pile penetration and withdrawal. Furthermore, the technique according to the present invention requires little energy and has a robust or relatively long useful life. The vibration frequency of the vibration device can advantageously be changed by changing the characteristics of the spring device, for example by changing the effective length or mass size of the spring, or a combination thereof.

  The natural vibration frequency of the engaged material / soil volume can be sensed using a sensor (eg underground sounder or accelerometer), thereby setting the vibration device to the desired vibration frequency, As a result, the stamping plate or pile / pile can be given the optimum vibration frequency, or the pile and ground system is given a vibration property that is at a desired value with respect to the vibration properties of the volume of the engaged material.

  The spring device can of course have any shape and design. The spring device can be arranged to give a linear motion to the mass, for example with or without rotation about the axis of motion. If, for example, the mass is ring-shaped and surrounds a pile, pile, etc., or if the pile is tubular and the mass is housed in a cavity, the spring device will extend into the mass and element And the arms are oriented to acquire relative rotational motion about an axis parallel to the direction of motion of the striking device. In this case, the spring arm generally lies on the cylindrical surface and can form a substantial angle with respect to the axial plane relative to the direction of the oscillating movement (stroke direction of the striking device).

  The invention will now be described by way of example with reference to the accompanying drawings.

  FIG. 1 illustrates a drop hammer 1 arranged to transmit a high energy content impact to a central area 4 of a plate lying over an area of soil 5. A passive vibrator is disposed in the peripheral portion of the upper surface of the plate 4. These passive vibrators include an inertial mass 2 supported on a plate 4 via springs 3.

  The force transmitted to the soil by the plate 4 will engage the soil volume 5. The vibration movement of the engaged earth volume 5 can be recorded by the sensor 7. The vibratory motion of the passive vibrator can be recorded by the sensor 6. By changing the size of the mass 2 and / or the spring 3, the resonant vibration frequency of the plate can be adjusted to match the natural vibration frequency of the soil volume 5 engaged.

  With the present invention, the applied vibration can be brought to correspond to the natural vibration frequency of the system (or to the overtone or other desired vibration of the natural vibration frequency) so that a strong amplification of the vibration is obtained. This is usually controlled by suppression in an undesirable manner. However, in the present invention, the resonance effect is used to increase the amplitude of vibration of the object in question (stamping plate or pile / pile) and extend the duration of the oscillating motion. This means that the system can be set to extended oscillating motion within the desired frequency range with the aid of a short term impact (eg hammer or vibrator) in motion. This principle can be used, for example, during the driving and removal of piles and piles when the vibrations and soil are consolidated.

  In the example shown in FIG. 2, the pile 4 is driven directly into the formation by the sledge hammer 1. The pile 4 is surrounded by a mass (or mass unit) attached to the pile 4 via the spring element 3 so that the mass 2 can move axially relative to the pile 4. As shown in FIG. 2, sensors 6 and 7 can be attached to a passive vibrator or pile, corresponding to the natural vibration frequency of the object being struck to allow the pile 4 to penetrate the formation 5 effectively. Provide a vibration frequency (or other suitable frequency, eg, natural frequency overtones). Further, in some cases, for example, when the formation 5 is non-viscous soil, the natural frequency of the system can be lowered at the final hammering stage in order to generate a compressive effect of the soil material 5 surrounding the pile 4. It is recommended to use a suitably shaped compression device during consolidation.

  The invention is of course not limited to the specific examples used in areas of foundation laying, but in principle can be used to drive rigid objects into other materials or for the compression of all types of materials. it can. A prominent feature of the present invention is the efficient amplification of the energy applied by the hammer system, which results in energy savings and thus a long useful life.

  By way of example, various conventional pile drive or ground compression machines must be used for striking or vibrating. There is no equipment that can combine striking and vibration in a simple and efficient manner. The drop hammer can have a mass of 4 to 20 t and a drop of 1 to 5 m. The drop hammer transmits its stroke energy to the pile as a short impact. In the case of vibrations, the pile is subjected to the oscillatory motion produced by the rotating eccentric mass. These produce centrifugal forces of about 500 to 2000 kN and operate at vibration frequencies in the range of 15 to 40 Hz. In order to increase penetration during vibration, it is desirable to be able to vibrate at a considerably higher frequency of 80 to 100 Hz, which corresponds to the natural frequency of the pile. At such high vibration frequencies, energy loss and therefore wear is very high in active vibration systems.

  According to the invention, the resonance frequency of the vibration device is preferably matched to the natural vibration frequency of the vibration system, or above it, ie at a distance from the natural frequency to zero, or a frequency that gives the desired amplification effect. Set to distance. Such an amplification effect is obtained within a certain frequency interval, so that even if the vibration device does not operate correctly at the natural frequency (or above it) of the vibration system, the amplification effect is selected or fixed. An amplification effect can be obtained.

  In the embodiment of driving (or removing) the pile, the inertial mass is shown arranged around the outside of the pile. However, it is clear that if the pile is tubular, the inertial mass can be placed in the cavity of this element. In this case, the arrangement must ensure that the elongate element is not subjected to any major bending buckling force.

  FIG. 3 illustrates how the hammer 1 strikes the mass 2 inside the hollow pile 4. Again the mass 2 is supported by the pile 4 via the spring device 3.

  FIG. 4 shows a variant of the object shown in FIG. 3, in which the mass 2 is arranged around the outside of the pile 4. The sledge hammer 1 comprises a stamping plate 11 for simultaneously transmitting the hammer stroke to the mass 2 via the protective element 12 on the mass 2. If the mass 2 is a link type, the stamping plate 11 is naturally a ring shape like the protective element 12.

  FIG. 5 shows a specific example similar to the object of FIG. 1, but here the vibration energy is not supplied via a sledge hammer, but is supplied via a vibrator 100. Vibrator 100 is supported by mass 2 of the vibrator and includes a stand 104 with two eccentric masses 105 rotating in opposite directions and preferably at the same speed about parallel axes. Vibrator 100 is arranged to move mass 2 in motion toward and away from compression plate 4. The frequency of the vibration device can be set by appropriate selection of the vibrator 100 vibration frequency.

  Vibrator stand 104 supports stabilizing mass 107 via suppressor 106. Since the vibrator 100 directly acts on the mass 2 of the vibration device supported from the compression plate 4 via the spring 3, the embodiment according to FIG. 5 releases high compression energy even with a relatively small vibrator 100 according to the discussion above. can do.

  FIG. 6 shows an embodiment based on the embodiment shown in FIG. 1, but supplemented to provide prestressing of the spring 3 supporting the mass 2. FIG. 6 illustrates two different embodiments of the prestressing member.

  On the left side of FIG. 6, a tension rod 201 is shown secured to mass 4 by a fixture 207. The rod 201 extends through the mass 2 in the direction of oscillating motion. The upper end of the rod 201 is provided with a nut 212 that cooperates with the thread on the upper end of the tension rod 201. The spring 3 can be compressed by the mass 2 being pushed down towards the plate 4 by any suitable equipment available on site such as loading a drop weight, after which the weight is removed from the mass 2. A nut 212 is applied to maintain the compression of the hour spring 3.

  On the plate 4 a locking device 209 is shown. Each locking device 209 is composed of a lever 206 having a lower end that is supported on the plate 4 through a universal bearing 203. At the lower end of the lever 206, there is a flange 204 extending from the lower surface of the drop weight 1. The upper end of lever 206 includes an angled end portion 208. The lever portion 208 grips the inner edge of the mass 2 when the lever 206 is tilted somewhat outward from a position perpendicular to the surface of the plate 4 passing through the bearing 203. The nut 212 can be removed so that the compression of the spring 3 is maintained by the locking device 209. The compression unit can now be arranged with a prestressed spring on a suitable ground 5. Now the sledgehammer can be dropped toward the center of the plate 4 to transmit its striking energy, at which time the falling weight 1 simultaneously releases the locking device 209 and releases the energy prestressing the spring, The resulting mass is set to oscillating motion with respect to the plate 4. The thrust energy from the falling weight 1 and the reflected energy from the soil volume 5 are returned to the mass 2 via the spring 3.

  The right side of FIG. 6 illustrates another embodiment of prestressing, in which the spring 3 is aided by a wire 210 that extends, for example, through an opening in the mass 2 around the return roller 211 on the plate 4 and from there back to the mass 2. Is prestressed. For example, the wire 210 rises through an opening in the mass 2 and joins the load distribution plate 212 seated on the upper surface of the mass 2. The tensile force of the wire 210 can be obtained prior to the next stroke with the help of hoist means for lifting the drop weight 1.

  FIGS. 7 and 8 illustrate a mass 5 supporting a vibrator stand 301 in which a pile and a plate 4 are connected to an inertial mass 2 via springs 3 respectively. The stand 301 also supports an additional mass 302 via a suppressor 303. Vibrator 300 is excited by a rotating eccentric weight 304.

  FIG. 9 illustrates a frame 401 mounted on a non-circular wheel 402 that travels on the ground 5. A drive means, for example a vehicle 403 such as a tractor, is shown for towing the frame 401 via a tow bar 404. The frame 401 contacts the ground 5 and supports a compression plate 405 parallel thereto. The frame 401 also supports the inertial mass 2 via a spring 3 that allows vertical vibration movement. When the tractor 406 pulls the compression machine 400 sideways, a vertical vibration motion is generated in the mass 2 via the spring 3 by the non-circular wheel 402 and this motion is transmitted to the compression plate 405 and resonates in the manner previously described. Amplified by effect. Oscillating motion is transmitted through the frame 401 to the compression plate 405 that is in contact with the underlying mass 5 when at least the frame 401 and the plate 405 assume their lowest position when the wheel 402 rotates. The frequency of this compression system is adjustable by changing the dynamic characteristics of the spring and mass. The radially protruding portion of the wheel 402 has a relatively limited carrying capacity and penetrates into the foundation 5. However, as the wheel continues to rotate, the circumferentially extending wheel protrusion can lift the trolley / frame.

  The plate 405 is preferably arranged so that it can be adjusted perpendicular to the wheels for adjustment to the ground of varying carrying capacity. The geometric shape of the wheel 402 is not limited to the shape shown and can be, for example, a triangle, hexagon, or handle wheel, or other shape that imparts a vibrating motion to the wheel when it rotates along the ground. The wheels 402 can be connected or steered together to provide a synchronous uniform vertical displacement motion.

1 is a vertical sectional view of an apparatus for ground compression according to the present invention. 1 is a schematic vertical sectional view of a pile driving device according to the present invention. Fig. 2 illustrates a pile drive device in which a hammer stroke is applied via a spring and to the mass supported inside the tubular pile. FIG. 4 illustrates a device corresponding to FIG. 3 but having a pile surrounded by mass. 1 illustrates an apparatus for supplying vibration energy to the mass of a vibration device with the aid of a vibrator cradle. Fig. 2 illustrates the device shown in Fig. 1 with the addition of a member for prestressing the spring of the vibration device. Fig. 4 illustrates a deformation device in which a vibrator stand supporting a vibrating member is directly supported by a vibrator mounted on a pile or compression plate. Fig. 4 illustrates a deformation device in which a vibrator stand supporting a vibrating member is directly supported by a vibrator mounted on a pile or compression plate. Fig. 4 illustrates another embodiment according to the present invention.

Claims (28)

A method for driving an element in direct contact with a mass of material such as a formation, the element comprising a stamping plate in surface contact with it to compress the mass of material, or the mass of material Consisting of an elongate object such as a pile or pile driven or pulled axially, the element being essentially supported by the element via a spring device for movability in the compression direction or in the driving or withdrawal direction A vibration device comprising a mass, the method comprising:
The method wherein the vibration device is vibrated either by the mass or by a vibrator supported by the element or by a thrust from a striking device against the element or the mass of the vibration device.   The method of claim 1, wherein the vibrator is vibrated by a vibrator supported by the vibrator, and the vibrator has a variable frequency of vibration.   The method of claim 1, wherein the striking device applies thrust to either the element or the vibration device.   4. The method of claim 3, wherein the striking device applies its thrust through an intermediate plate.   The vibration device spring device is prestressed and unloaded when thrust is applied by the striking device to release the mass of the vibration device to the prestressed spring device for vibrational motion relative to the element. 5. A method according to any one of claims 1 to 4, characterized in that:   The vibration device is set to a resonance frequency that is at, or at a selected distance from, or above a natural vibration frequency for the mass of material engaged by the element. Any one of methods 1 to 5.   7. The element according to claim 1, wherein the element to be struck is an elongated object and the inertial mass surrounds the elongated object or is housed in a hollow cavity of the elongated object. Method.   8. A method according to claim 1, wherein the vibrational nature of the mass of material is sensed and the resonant frequency of the vibratory device is set in response to the sensed dynamic response of the system.   9. A method as claimed in any preceding claim, wherein the vibrator comprises a stand attached directly to the element and supporting the inertial mass via the spring.   The element is a stamping plate supported near the surface of the mass of material by a trolley mounted on a non-circular wheel, the wheel supports an inertial mass via a spring, and the trolley is attached to the surface of the mass of mass. 9. A method as claimed in any one of the preceding claims, characterized in that it is moved along, so that the non-circular wheel imparts a vertical oscillating movement to the trolley. An apparatus for driving an element in direct contact with a mass of material such as a formation, the element comprising a stamping plate in surface contact with that for compressing the mass of material, or the mass of material Comprising an elongate object such as a pile or pile driven or pulled axially, the element comprising a vibrating device comprising an inertial mass supported by the element via a spring device for mobility relative to the element ,
The vibration device is arranged to be vibrated by a striking device that applies thrust to the element or by a vibrator acting directly on the element or the mass of the vibration device.   12. The apparatus of claim 11, wherein the vibrator is arranged to set a mass of the vibration device with respect to the element in vibration, and the vibrator has a variable vibration frequency.   13. The apparatus of claim 12, wherein the vibrator supports a stabilizing mass via a suppressor.   12. The apparatus of claim 11, wherein the striking device is arranged to apply a thrust to the mass of the element or the vibration device.   15. The apparatus of claim 14, wherein the striking device is arranged to apply its thrust through an intermediate plate.   A member for pre-stressing the spring device of the vibration device, and the spring when the striking device applies thrust to the element to release the mass of the vibration device for vibrational movement relative to the element; 16. The device according to claim 14, further comprising a release member for releasing the device.   The vibration device is adjustable with respect to its resonance frequency so as to enable the resonance frequency, which is selected from the natural frequency for the system containing the appropriate material area of the element or a frequency above it. Device according to any of claims 11 to 16, characterized in that it is a distance.   18. The device of claim 17, wherein the resonance frequency for the passive vibration device is adjustable by changing the size of the mass and / or specific adjustment of the spring device.   The element to be struck is a pole, tube, stake or other elongate element that is driven down or pulled out of the mass of material and the mass surrounds or is struck by the element to be struck 19. The device according to claim 11, wherein the device is contained in a hollow cavity of the element.   The element to be struck is a stamping plate, the stamping plate being in surface contact with the mass of material to compress the material underneath and supporting the passive vibration device. The apparatus according to any one of 11 to 18.   Sensing a dynamic response from a mass of material engaged by the element and, for the vibration device, selection from natural frequencies or overtones for a system that includes the material area engaged by the element 21. A device according to any one of claims 11 to 20, further comprising a sensor device that enables the vibration frequency to be set to a specified frequency distance.   The apparatus of claim 21, wherein the vibration frequency is arranged to be essentially adjustable to the natural frequency of the system or its overtone or to a selected frequency distance therefrom.   The element to be struck is an elongated object such as a pole or stake, and the vibration frequency of the vibratory device is such that the mass of material is compressed in the area near the elongated object while the object is being driven or at the end of this process. 23. The device of claim 22, wherein the device is arranged to be reduced relative to the natural frequency of the mass of material engaged.   24. A device according to any one of claims 11 to 23, characterized in that the restraining means are arranged between the element to be struck and the vibration device in order to adjust the force transmission characteristics between them.   25. A device according to any of claims 11 to 24, wherein the spring device is arranged to establish a reciprocating motion substantially directly on the mass of the vibration device.   The spring device is arranged to impart a reciprocating rotational motion about the linear motion axis to the mass of the vibration device, the spring forming a substantial angle with respect to the axial plane of the rotational motion and a cylinder 26. Apparatus according to claim 25, characterized in that the surface, preferably its axis, is oriented substantially tangential to the cylindrical surface defined by the axis of rotational movement.   12. The apparatus of claim 11, wherein the vibrator includes a vibrator stand supported directly by the element and supporting the inertial mass via a spring.   The element is a stamping plate supported near the surface of the mass of material by a trolley mounted on a non-circular wheel, and the wheel supports an inertial mass via a spring, and the trolley 12. The apparatus of claim 11, wherein the apparatus is moved along a surface so that the non-circular wheel imparts a vertical oscillating motion to the trolley.

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