JP4885791B2 - Pile dynamic horizontal loading test equipment - Google Patents

Description

The present invention relates to horizontal loading test equipment pile which gives the horizontal dynamic loads to the pile head.

  As a horizontal loading test method for piles, there is a test method for applying a static load to the pile head, and ground parameters such as ground resistance are obtained from the relationship between load and displacement. In addition, this test method is classified into positive and negative alternating loading and one-way loading depending on the loading direction, and is classified into stage loading and continuous loading depending on the loading time.

  FIG. 6 shows an example of a static horizontal loading test (positive and negative alternating loading). A hydraulic jack 91 is arranged as a force device on both sides of the test pile 90 and a reaction force is applied to the reaction force pile 92. A horizontal static load is applied to the test pile 90. A hydraulic jack 91 is connected to two reaction force piles 92 through a reaction force device composed of an H-shaped steel member 93 and a PC steel rod 94. A load cell 95 is disposed between the test pile 90 and the hydraulic jack 91. (For example, refer to Patent Document 1).

JP 2005-315611 A

  In a conventional static horizontal load test, a hydraulic jack is used as a force application device, and thus a reaction force device is necessary, and this reaction force device has been a problem. That is, (a) the influence of the reaction force device is inevitably mixed in the test results, (b) the reaction force device is necessary, the test device becomes large, and it takes days to prepare for the test, There were problems such as high costs.

  As a method for solving such problems of the static horizontal loading test, a bell-position dynamic horizontal vibration method has been considered, but the weight is removed from the upper horizontal beam material of a simple support frame with a wire or the like. It is a simple device that suspends and swings a weight that is swung up and collides with a pile head via a cushioning material such as foamed polyurethane, and is applied to thin piles and wooden piles.

  In addition, in order to solve the problems of the static horizontal loading test described above, the applicant can perform a highly accurate horizontal loading test at a low cost without a reaction force device and with a short experiment time. In addition, a dynamic horizontal loading test method for piles that can perform dynamic horizontal loading tests such as large-diameter steel pipe piles and concrete piles with a relatively simple test device in the weight horizontal dynamic horizontal loading test And a dynamic horizontal loading test apparatus has already been filed (Japanese Patent Application No. 2005-335844). In this dynamic horizontal loading test, the weight is moved by human power or power along a rail installed on the ground or installed on the ground, and the weight is made to collide with the pile head to cause a horizontal dynamic load. Is added.

  However, even in such a dynamic horizontal loading test method and apparatus, when a person pushes the weight and moves it along the rail, there are the following problems. That is, (1) A large number of people are required for the test, (2) A long rail is required to obtain a large vibration, (3) A large vibration cannot be obtained, (4) A wide test place Space is required, and the area for excavating the ground becomes large. (5) Fine adjustment of the impact force is difficult. (6) Because the person pushes the weight, there is a risk of injury. (7) The person is a pile. Since it runs near the ground, the ground vibrates and noise enters the measuring instrument (accelerometer, etc.). (8) Since people are placed on the ground near the pile, the pile is restrained, affecting the vibration of the pile. , (9) Large equipment, (10) High transportation costs, (11) Time required for assembly, (12) Bad appearance.

The present invention has been made to solve such a problem. In a dynamic horizontal loading test using a weight and a rail, the test can be performed by a small number of people, and a large amount is added by a low-priced and compact device. force is obtained, there is provided also capable of dynamic horizontal loading test equipment adjustment of the striking force.

  In the horizontal loading test of piles (steel pipe pile, H steel pile, concrete pile, steel concrete composite pile, etc.), the present invention is a dynamic horizontal loading test using a weight instead of a static horizontal loading test using a conventional hydraulic jack. In addition, the weight is supported by the ground rail system or the suspension type monorail system instead of the bell thrust system, the traveling carriage with a driving device is run along the rail, and the weight mounted on the traveling carriage is horizontally moved, It is made to collide with a pile head and vibrate (see FIG. 1).

  The reaction force device in the conventional static horizontal loading test is no longer required, the influence of the reaction force device is not mixed in the test results, and the test device can be simplified, so the experiment preparation is easy and the test is short. It can be performed in a timely manner, and an accurate horizontal loading test can be performed at low cost.

  Moreover, since it is a rail system, there exist the following advantages compared with a bell-butt system. (A) Because it moves along the rail, a heavy weight can be easily applied. (B) By using potential energy, elastic energy, or pressure energy, the impact speed of the weight can be easily increased. (C) The weight of the weight can be easily increased by increasing the cross section of the rail, (d) The reaction after the collision of the weight can be controlled with a simple device, etc. (e) Since it is only necessary to install rails, it is easy to be mobile.

  Furthermore, there are the following advantages compared with the case where the weight is moved manually by the rail method. (1) The test can be done with a small number of people, (2) A large vibration can be obtained with a short rail, (3) A large vibration can be obtained, (4) A test even in a small test area It is possible to reduce the area for excavating the ground to expose the pile head embedded in the construction, (5) Fine adjustment of the striking force is possible, (6) Human weight It is safe because it doesn't push down. (7) Since people do not get close to the pile, the ground does not vibrate when people run, and noise (such as accelerometers) does not enter. (8) People Does not rest on the ground near the pile, so the pile is not restrained and does not affect the vibration of the pile, (9) the equipment is compact, (10) transportation costs are low, (11) time to assemble Does not take, (12) Good-looking, etc.

The invention according to claim 1 of the present invention, the dynamic horizontal loading test of piles by weight to pile head projecting ground pouring been piles added horizontal dynamic loads seek deformation characteristics of pile It is a device, and comprises a rail installed on the head of the pile or installed on the ground, a traveling carriage with a driving device installed movably along the rail, and a weight mounted on the traveling carriage. In the dynamic horizontal loading test device for piles, the weight is supported on the traveling carriage so as to be movable in the movement direction of the carriage, the rear surface opposite to the front surface that collides with the pile head of the weight, and the rear frame of the traveling carriage A dynamic horizontal loading test apparatus for piles, in which a shock absorbing member for absorbing an impact is provided between the two.

The invention according to claim 2 of the present invention is the pile dynamic horizontal loading test apparatus according to claim 1 , wherein the driving device of the traveling carriage rotates the wheels of the traveling carriage, and the weight is the pile head. It is the dynamic horizontal loading test apparatus of the pile characterized by being comprised so that the power supply of an electric motor may be turned off before colliding with a part.

  In the present invention, since the weight is placed on the traveling carriage and collides with the pile head, it is necessary to protect the drive unit from the impact caused by the impact. Therefore, the weight is mounted on the traveling carriage by a leaf spring or the like, the weight is supported so as to be movable in the traveling direction, and the shock is absorbed by a buffer member such as rubber.

  The invention according to claim 6 of the present invention is the electric horizontal loading test apparatus for piles according to claim 4 or claim 5, wherein the driving device of the traveling carriage rotates the wheels of the traveling carriage, A dynamic horizontal loading test device for a pile, wherein the electric motor is turned off before the weight collides with the pile head.

  In a traveling system using wheels and an electric motor, a sensor such as a limit switch is placed in front of the pile head of the rail. When this sensor is activated, the electric motor is turned off, and when the weight collides with the pile head, the motor In addition, the electric motor operates as a generator when the electric motor rotates backward when the vehicle returns after a collision, and the movement of the weight in the rebound direction is attenuated due to energy consumption.

  In the present invention, a ground rail system that moves on the rail with a moving jig attached to the lower part of the weight, or a suspended monorail system that suspends the weight from the rail via a moving jig that moves on the rail. Can be adopted. One rail may be sufficient and two or more rails may be sufficient. As the moving jig, a wheel system that rolls on the rail, a slider system that slides on the rail, or the like can be used.

  When a wheel system is used for the moving jig, if a reverse rotation prevention mechanism such as a ratchet and a ratchet claw is provided on the wheel, the weight can be prevented from returning in a reaction after the collision. As a result, it is possible to extend the dynamic loading time due to the weight, increase the dynamic load, and prevent danger during the test.

  Since the present invention is configured as described above, the following effects can be obtained.

 (1) Since the weight is moved horizontally along the rail, and the pile head collides with the pile head and vibrates, there is no need for a reaction force device in the conventional static horizontal loading test, and the influence of the reaction force device on the test results is eliminated. Since it does not mix and can be a simple test apparatus, the preparation for the experiment is easy, the test can be performed in a short time, and a precise horizontal loading test can be performed at a low cost.

 (2) Since the rail system is used, it is possible to easily apply a heavy weight, and the weight self-propelled system using a traveling carriage with a drive unit can easily increase the impact speed of the weight. The weight of the weight can be easily increased by increasing the cross section of the weight, and the recoil after the collision of the weight can be controlled with a simple device, etc. Dynamic horizontal loading test can be carried out.

 (3) Although the reaction force device generally uses a pile, in the present invention, since the reaction force device is not required, it is possible to perform a horizontal loading test with only one pile, and a lower cost horizontal loading test is possible. Become.

 (4) Since the weight is moved horizontally by the self-propelled weight system using a traveling carriage with a drive unit, and it strikes the pile head and vibrates, it can be tested by a small number of people, and it is a low-priced and compact device. As a result, a greater excitation force can be obtained, and the impact force can be adjusted.

 (5) It is safe because a person does not push the weight, and by turning off the power of the electric motor before the pile head, the load on the electric motor at the time of collision is eliminated, and reverse rotation after the collision The consumption of energy can attenuate the movement of the weight in the rebound direction, and a safer horizontal placement test is possible.

(6) By configuring the load detector installed at the pile head collision point with a load cell and a buffering jig consisting of a coil spring, etc., the impact load due to the weight can be smoothly transmitted to the pile head. it can. Further, when the effect of the cushioning material is large, the dynamic loading time can be extended.

  Hereinafter, the present invention will be described based on the illustrated embodiments. This embodiment is a case where it is applied to a horizontal loading test of a steel pipe pile, and is an example of a dynamic horizontal loading test using a ground rail type weight. FIG. 1 is a plan view and a side view showing an example of a weight self-running type dynamic horizontal loading test using a traveling carriage with a driving device of the present invention. FIG. 2 is an elevation view, a plan view, and a side view showing the traveling carriage portion.

  As shown in FIG. 1, a plurality of steel pipe piles 1 are placed on the foundation ground of the structure at intervals in the vertical direction and the horizontal direction, and the pile head 2 protrudes on the ground at a predetermined height. Yes. In the present invention, a dynamic horizontal loading test is performed on such a pile head 2 by the weight self-propelled type using a traveling carriage with a driving device and a dynamic horizontal loading test device 10 of a weight method and a rail method. .

  In the embodiment of FIG. 1, the dynamic horizontal loading test apparatus 10 includes an apparatus base 11 made of a pair of left and right steel members and the like installed on the ground toward the pile 1, and a pair of left and right steel members of the apparatus base 11. It is composed of a rail 12 to be installed and a weight 13 that can move along the rail 12. The weight 13 is mounted on a traveling carriage 14 with a drive device, and is moved away from the pile head 2 of the rail 12. A dynamic horizontal loading test is performed in which the traveling carriage 14 travels from the rear side toward the pile head 2 along the rail 12 at a predetermined speed, and the weight 13 collides with the pile head 2 to vibrate.

  In the embodiment of FIGS. 1 and 2, the traveling carriage 14 is a traveling system using wheels and an electric motor. Wheels 16 with flanges that roll on the pair of left and right rails 12 are arranged on the left and right sides of the frame 15 of the traveling carriage 14 in the front and rear direction of the traveling direction.

  The electric motor 17 as a driving device is arranged in a pair of left and right so as to rotationally drive each of the pair of left and right wheels 16. In the illustrated example, the front wheel 16 on the pile head 2 side is driven. The driving wheel 16 and the electric motor 17 are connected by a belt and a pulley, for example.

  The weight 13 is disposed in the center on the bottom plate of the frame 15 of the traveling carriage 14 along the traveling direction, and the front surface of the weight 13 collides with the pile head 2. Moreover, in this apparatus, it is necessary to protect a drive part from the impact by a pile hit | damage. Therefore, the weight 13 runs with the movement jig | tool 18 arrange | positioned between the bottom face of the weight 13 and the baseplate of the flame | frame 15. A buffer member 19 is disposed between the rear surface of the weight 13 and the rear frame 15a of the frame 15 of the traveling carriage 14 so as to be movable in the direction.

  As shown in the figure, the moving jig 18 is a method of connecting the weight 13 and the bottom plate of the frame 15 with a leaf spring that can be deformed in the traveling direction, or a jump preventing device (not shown) using a roller, a pin, and a hook metal fitting. Etc. can be used. As shown in the figure, the buffer member 19 may be a member in which rubber is sandwiched between a pair of mounting steel plates. Other buffer members can also be used. Further, a hook (not shown) that engages the rail 12 can be provided on the traveling carriage 14 so that the traveling carriage 14 does not take off when the weight 13 collides.

  Further, a sensor such as a limit switch is disposed in front of the pile head 2 of the rail 12, and the electric motor 17 is turned off by the operation of this sensor. When the weight 13 collides with the pile head 2, it is possible to prevent the electric motor 17 from being loaded. Further, when the weight 13 collides with the pile head 2 and returns by reaction, the electric motor 17 rotates reversely and operates as a generator, and acts as a regenerative brake to attenuate the movement of the weight 13 in the rebound direction. be able to. In addition, a clutch and a brake can be provided. The power source is taken from a switchboard installed on the traveling carriage 14 or the like, and is remotely operated at a location away from the device.

  In the configuration as described above, the traveling carriage 14 is arranged on the rear side in the direction away from the pile head 2 by moving on the rail 12 to fix the traveling carriage 14. From this state, the electric motor 17 is driven to cause the traveling carriage 14 to travel toward the pile head 2, the weight 13 on the traveling carriage 14 collides with the pile head 2, and the pile head 2 is loaded. The traveling speed of the weight 13 can be adjusted by appropriately setting the rotation speed and traveling distance of the electric motor 17.

  When the weight 13 collides with the pile head 2, the impact is absorbed by the moving jig 18 and the buffer member 19, and damage to the drive unit is prevented. Further, derailment of the traveling carriage 14 is also prevented. Furthermore, when the electric motor 17 is turned off immediately before the collision, there is no load on the electric motor 17 at the time of the collision, and when the electric motor 17 reversely rotates after the collision, the electric motor 17 reversely rotates. Directional movement can be attenuated.

  As shown in FIG. 3, the pile head 2 is set with a working height H of a horizontal load, and a load detector 30 using a load cell is provided on the pile head 2 at this working height level. The dynamic load (impact load) due to the weight is measured. Displacement detectors 31 using displacement meters are arranged on both the left and right sides in the direction perpendicular to the movement, and the horizontal displacement of the pile is measured. In addition, accelerometers (horizontal acceleration) and strain gauges (shear) 32 are attached to the left and right side surfaces of the pile head 2 in the direction perpendicular to the movement, and the horizontal acceleration and shear strain of the pile are measured. In addition, accelerometers 33 are attached to the front (weight side) / rear surface (anti-weight side) and the left and right sides of the weight 13 in the moving direction of the pile head 2, and the horizontal acceleration / vertical acceleration of the pile, the weight The horizontal acceleration of is measured.

  The center axis of the cylinder of the weight 13 is adjusted so as to coincide with the action height level, and the center of the front surface of the weight 13 collides with the load detector 30. FIG. 4 is a plan view and a horizontal cross-sectional view showing an example of a load detector provided with a buffering jig. The load detector 30 includes a load cell 40 for measuring a dynamic load of the pile head 2. A shock-absorbing jig 41 having a built-in coil spring is provided on the weight side of the load cell 40 so as to adhere to the outer surface, so that an impact load caused by the weight 13 can be smoothly transmitted to the pile head 2.

  The buffer jig 41 has an inner tube 42 fitted on the outer periphery of the cylindrical casing of the load cell 40, and an outer tube 43 is fitted on the outer periphery of the inner tube 42 so as to be slidable in the axial direction, and the lid of the load cell 40 and the outer tube 43. A coil spring 45 is disposed between the coil spring 44 and the coil spring 45 so as to absorb an impact by compressive deformation. Further, load transmission members 46 and 47 serving as cushion materials and stoppers are respectively attached to the weight side of the load cell 40 and the anti-weight side of the lid body 44 so that a predetermined gap is formed therebetween. , 47 is arranged outside the coil spring 45. The load transmission members 46 and 47 are preferably made of a relatively cushioning material such as hard plastic rather than hard metal. Further, a steel plate 48 with rubber attached to the surface is attached to the surface of the lid 44 on the weight side. The rubber may be attached to the weight. A support fitting (not shown) such as a bracket is attached to the outer surface of the pile head 2, and the load detector 30 is placed thereon.

  As shown in FIG. 3, the displacement detector 31 includes a displacement meter 50 and a cylinder-type elastic member 51. A mounting piece 52 is fixed to the side surface of the pile head 2, and the distal end of the telescopic rod 51 a of the telescopic member 51 is attached to the mounting piece 52, and the base end portion of the cylinder main body 51 b is attached to the beam 27 orthogonal to the rail 11. Is fixed. The displacement meter 50 is horizontally disposed under the expansion / contraction member 51 disposed horizontally at the working height level, the rod tip of the displacement meter 50 is connected to the expansion / contraction rod 51a, and the displacement of the pile is measured. The displacement meter 50 is installed by installing the beam 27 for installing the displacement meter at a position sufficiently away from the test pile and supporting both ends with a large-section pile such as H-shaped steel or a beam between the piles. The beam 27 can be a stationary beam, and accurate displacement measurement can be performed.

  The displacement measurement of the test pile can be performed by the accelerometer 32 attached to the test pile in addition to the displacement meter 50 described above. Integrate acceleration twice to determine displacement. The displacement waveform obtained from the displacement meter 50 has high frequency noise over a wide band, while the displacement waveform obtained from the accelerometer 32 has no high frequency noise. This high frequency noise is presumed to be caused by the mounting structure of the displacement meter 50, the vibration of the fixing member, and the like, and the displacement waveform obtained from the accelerometer 32 is lower than the displacement waveform obtained from the displacement meter 50. Is underestimated. From the above two points, it is preferable to use a displacement meter 50 to remove high frequency components by a high cut filter. An optical non-contact displacement meter that does not require a stationary beam can also be used.

  Although the illustrated example shows a ground rail system that moves on the rail using a moving jig attached to the lower part of the weight, the weight is suspended from the rail via the moving jig that moves on the rail. It can also be applied to a suspended monorail system. In any system, the number of rails may be one, or two or more. Moreover, although the moving jig | tool showed the wheel system which rolls on a rail, the slider system etc. which slide on a rail can be used. Furthermore, the rail is not limited to being horizontal, and can be inclined with a downward slope toward the pile head, for example.

  In addition, although the above demonstrated the case where it applied to a steel pipe pile, it cannot be overemphasized that it can apply also to a concrete pile and another pile.

It is the top view and side view which show an example of the dynamic horizontal loading test of the self-propelled weight type by the traveling trolley with a drive unit of the present invention. FIG. 2 is an elevation view, a plan view, and a side view showing a traveling carriage portion of FIG. 1. It is an example of the displacement measuring device of the pile head used by this invention, (a) is a side view, (b) is a top view. It is an example of the load detector provided with the buffering jig used by this invention, (a) is a top view, (b) is a horizontal sectional view. It is an example of the conventional static horizontal loading test apparatus, (a) is a top view, (b) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steel pipe pile 2 ... Pile head 10 ... Dynamic horizontal loading test apparatus 11 ... Apparatus mount 12 ... Rail 13 ... Weight 14 ... Running carriage 15 ... Dolly frame 15a ... Rear frame 16 ... Wheel 17 ... Electric motor (drive device) )
DESCRIPTION OF SYMBOLS 18 ... Moving jig 19 ... Buffer member 27 ... Beam for installation of displacement meter 30 ... Load detector 31 ... Displacement detector 32 ... Accelerometer / strain gauge (shear)
DESCRIPTION OF SYMBOLS 33 ... Accelerometer 40 ... Load cell 41 ... Buffering jig 42 ... Inner tube 43 ... Outer tube 44 ... Lid body 45 ... Coil spring 46, 47 ... Load transmission member 48 ... Steel plate 50 ... Displacement meter 51 ... Stretch member 51a ... Stretch Rod 51b ... Cylinder body 52 ... Mounting piece

Claims (2)

It is a dynamic horizontal loading test device for piles that determines the deformation characteristics of a pile by applying a horizontal dynamic load to the pile head protruding above the ground of the driven pile by a weight.
A rail installed on the ground or toward the pile head, a traveling carriage with a driving device installed movably along the rail, and a weight mounted on the traveling carriage, on the traveling carriage The weight is supported so as to be movable in the movement direction of the carriage, and a shock absorbing member is provided between the rear face opposite to the front face that collides with the pile head of the weight and the rear frame of the traveling carriage. A dynamic horizontal loading test device for piles, characterized in that The dynamic horizontal loading test apparatus for a pile according to claim 1 , wherein the driving device of the traveling carriage is an electric motor that rotationally drives the wheels of the traveling carriage, and the power source of the electric motor before the weight collides with the pile head. A dynamic horizontal loading test apparatus for piles, characterized in that the pile is configured to cut through.

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