JP2016102695A - Displacement measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a durable displacement measurement device capable of highly accurately measuring a displacement even in the case of being installed at a point affected by striking of a structure.SOLUTION: A displacement measurement device 1 for measuring a displacement generated when a pile P driven in a ground G is struck comprises: a support base part 2 installed at a distance from the pile P; a spring part 3 connected to the support base part; a weight part 4 oscillatably supported by the spring part; and a laser type displacement meter 6 for measuring a relative displacement generated between a side face 43 of the weight part and a side face P2 of the pile.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a displacement measuring apparatus used when a supporting body or the like is confirmed by hitting a structure such as a pile with a weight or a hammer that has been freely dropped.

  A pile stop management method that determines whether or not the tip of the pile has reached the support layer by measuring the displacement of the pile when the pile head is hit with a weight or a hydraulic hammer is known. (Refer patent documents 1-3 etc.).

  In addition, pile loading test methods such as rapid loading tests that measure the bearing capacity of piles by measuring the loading load and pile displacement when the pile head is hit with a weight are known (patents) Reference 4).

  In the pile stop management method and loading test method disclosed in these documents, the displacement amount of the pile at the time of impact is measured, but when using a device that measures the relative displacement amount, It is necessary to secure a fixed point that is not affected by the impact.

Japanese Patent No. 2700377 Japanese Utility Model Publication No. 4-30410 JP-A-5-25826 JP 2002-303570 A

  However, as described in Patent Documents 1-3, it is difficult to install a pile displacement measuring device at a fixed point at the site where the pile is placed due to restrictions such as the narrowness of the site and the presence of obstacles. The fact is that there are many.

  For this reason, in patent document 1, the displacement measuring device using the inertial force of the weight is attached to the side surface of the pile to measure the displacement. In this displacement measuring apparatus, a weight is suspended by a combination of a spring and a dashpot in the interior of the case fixed to the side surface of the pile.

  And while measuring the relative displacement of a weight and a pile (case) with a potentiometer, the absolute displacement of weight itself is calculated from the detected value of an acceleration sensor.

  That is, when a pile head is hit with a hydraulic hammer or the like, the pile moves in a high frequency range, but the weight suspended by the spring and the dashpot tries to stop at its original position due to inertial force, and even if it moves, the high frequency range It does not follow the movement of, but vibrates at a low frequency period (1 / several seconds).

  For this reason, in Cited Document 1, the movement of the weight is detected by an acceleration sensor, and the amount of displacement of the weight is calculated by integrating the acceleration twice, and added or subtracted to the measured value by the potentiometer of the pile.

  As described above, the displacement measuring device of the cited document 1 has a fast movement of the weight (1 / several seconds) because the weight is attached to the side surface of the pile, and two potentiometers and an accelerometer are also susceptible to impact. There is a risk of malfunction because it is placed in the environment.

  Therefore, an object of the present invention is to provide a displacement measuring device capable of measuring a displacement amount with high accuracy and being unlikely to fail even when installed at a point affected by the hitting of a structure. It is said.

  In order to achieve the above object, a displacement measuring device of the present invention is a displacement measuring device that measures the amount of displacement generated when a structure to be driven into the ground is hit, and is installed separately from the structure. A support base part, a spring part connected to the support base part, a weight part supported by the spring part in a freely swingable manner, and a relative generated between a side surface of the weight part and a side surface of the structure A displacement meter for measuring the displacement is provided.

  Here, it is preferable that the spring portion and the weight portion are adjusted so that the time until the movement starts due to vibration generated in the surrounding ground when the structure to be driven into the ground is hit is increased. For example, the time until the movement starts due to the vibration is adjusted to be 0.5 seconds or longer.

  Further, the support base part includes a flat base part and a columnar part that stands on the flat base part, and the spring part has a lower end fixed to the flat base part and an upper end connected to a bottom surface of the weight part, The weight portion may be provided with a guide portion that is movable in the vertical direction with respect to the columnar portion.

  On the other hand, the support base includes a support column extending upward and a projecting portion projecting from the upper part of the support unit toward the structure, and the upper end of the spring unit is fixed to the projecting unit. In addition, the lower end may be connected to the upper surface of the weight portion.

  Further, a laser displacement meter is attached to the side surface of the weight portion so that the displacement meter is irradiated with laser light in any one of the vertical directions, and the laser light is transmitted from the side surface of the structure. A reflection plate to be reflected can be projected.

  In addition, a contact-type displacement meter that measures a relative displacement generated between the side surface of the weight portion and the side surface of the structure is attached to the side surface of the weight portion or the side surface of the structure as the displacement meter. It can also be.

  Further, an accelerometer can be attached to the weight portion. Further, the displacement measuring device measures the amount of displacement generated when striking a structure to be driven into the ground, and is connected to the support base and the support base installed separately from the structure. An actuator part; a weight part supported by the actuator part; a displacement meter for measuring a relative displacement generated between a side surface of the weight part and a side surface of the structure; and an accelerometer attached to the weight part; The weight portion is fixed at a fixed position by the actuator portion that is controlled based on a signal detected by the accelerometer.

  The displacement measuring apparatus of the present invention configured as described above includes a support base part that is installed separately from the structure, and a spring part and a weight part connected thereto. And the relative displacement which generate | occur | produces between a weight part and a structure is measured with a displacement meter.

  Here, since the weight portion supported by the support base portion through the spring portion so as to be freely swingable tends to stop at the original position by the inertia force even when the support base portion vibrates, the start of movement is delayed as compared with the structure. Therefore, the relative displacement measured by the displacement meter before the weight portion starts to move can be regarded as the absolute displacement of the structure.

  For this reason, even if a displacement measuring device is installed at a point affected by the impact of the structure, it is not subject to impact force due to the impact, so it is difficult to break down and measure the displacement with high accuracy. Can do.

  Further, by adjusting the spring constant of the spring portion and the mass of the weight portion, it is possible to easily increase the time until the weight portion starts to move due to vibration generated at the time of impact. In particular, if the time until the movement starts due to vibration is set to 0.5 seconds or more, the displacement amount of the structure can be sufficiently measured before the weight portion starts moving in an impact loading test or a rapid loading test.

  Such a displacement measuring device is such that the lower end of the spring part is fixed to the flat base part of the support base part and the weight part is connected thereon, and the vertical movement with respect to the columnar part standing on the flat base part is possible. By providing the guide portion on the weight portion, it can be easily manufactured.

  Further, even if the support base part is provided with a column part extending upward and an overhang part projecting from the upper part and the weight part is suspended from the overhang part by a spring part, it can be easily manufactured. .

  In addition, a non-contact laser displacement meter is used to measure the relative displacement that occurs between the side of the weight and the side of the structure, so that damage can occur even if a large or repeated hit is made. It is possible to make a high-accuracy device.

  Also, a displacement measuring device can be easily manufactured by using a contact displacement meter that measures the relative displacement generated between the side surface of the weight portion and the side surface of the structure as the displacement meter.

  And by attaching an accelerometer to the weight part so that the acceleration can be detected, the absolute displacement of the structure can be calculated by correction even after the weight part starts moving. As a result, it becomes unnecessary to adjust the weight portion and the spring portion, or it is possible to measure an absolute displacement in a time zone that cannot be dealt with only by adjustment.

  Further, if the weight part is supported by the actuator part and the actuator part is controlled so that the weight part is fixed at a fixed position based on the signal detected by the accelerometer, the weight part and the support base part are configured. Can be miniaturized. It is also possible to fix the weight portion at the initial position (fixed position) for a long time.

It is explanatory drawing which showed the structure of the displacement measuring apparatus of embodiment of this invention. It is the graph which showed the relationship between a displacement and time, in order to demonstrate the shift | offset | difference of movement start with a pile and a weight part. It is explanatory drawing which showed the structure of the displacement measuring apparatus of Example 1. FIG. It is explanatory drawing which showed the structure of the displacement measuring apparatus of Example 2. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing the configuration of the displacement measuring apparatus 1 of the present embodiment. The displacement measuring device 1 is used to measure the amount of displacement generated when a structure to be driven into the ground G is hit.

  This Embodiment demonstrates the case where the pile head P1 of the pile P as a structure is hit | damaged with the weight W or the hydraulic hammer which were made to fall freely. The hitting of the pile head P1 is performed not only when the pile P is driven, but also during a rapid loading test, an impact loading test, and the like.

  The rapid loading test is a test method for piles P devised to eliminate the disadvantages of the static loading test and the impact loading test. According to this method, the loading time is 0.05 to 0.2 seconds, which is about 10 times the impact loading test. By setting the degree, it is possible to eliminate the influence of the propagation of elastic waves and obtain a highly reliable test result close to a static loading test.

  In the rapid loading test, a cushioning material (not shown) such as rubber is placed on the pile head P1 via a load meter (not shown), and the weight W is freely dropped thereon to hit the pile P. Thus, the loading time can be lengthened by interposing the cushioning material between the weight W and the pile head P1.

  On the other hand, when the weight W is dropped directly on the pile head P1, the impact load is loaded on the pile head P1 in a short time (about 0.01 to 0.02 seconds), and a wave phenomenon occurs in the pile P. The impact loading test is a test method for calculating the bearing capacity of the pile P based on the one-dimensional wave theory from the strain and acceleration generated in the pile head P1 in this short time.

  In these tests, the magnitude of the loaded load can be measured by a strain gauge (not shown) attached to the side surface P2 of the pile P or a hydraulic load cell installed on the pile head P1.

  And the displacement amount of the up-down direction (vertical direction) of the pile P is measured with the displacement measuring apparatus 1 of this Embodiment.

  The displacement measuring device 1 includes a support base 2 that is installed separately from the pile P, a spring part 3 connected to the support base 2, a weight part 4 that is supported by the spring part 3 so as to freely swing, It is mainly comprised by the laser type displacement meter 6 as a displacement meter which measures the relative displacement which generate | occur | produces between the side surface 43 of the weight part 4, and the side surface P2 of the pile P. FIG.

  An accelerometer 8 is attached to the side surface 43 of the weight portion 4 that is the periphery of the laser displacement meter 6.

  The support base part 2 is mainly composed of a tripod part 21 installed on the surface of the ground G, a flat base part 22 provided on the upper part of the tripod part 21, and a rail part 23 as a columnar part standing on the upper surface of the flat base part 22. Configured.

  The tripod portion 21 is configured such that the flat base portion 22 can be installed horizontally even when the ground surface is uneven. Further, the height of the flat platform 22 can be adjusted by the tripod 21.

  For the spring portion 3, for example, a spiral coil spring can be used. The lower end 31 of the spring portion 3 is fixed to the upper surface of the flat base portion 22, and the upper end 32 is connected to the bottom surface 41 of the weight portion 4.

  A coil spring having a known spring constant (k) is used for the spring portion 3. On the other hand, a member having a known mass (m) is used for the weight portion 4. The weight 4 is made of a member having such a weight that it can remain at the initial position for a desired time or longer by the law of inertia even when the support base 2 vibrates.

  The weight portion 4 is formed in, for example, a quadrangular prism shape or a cylindrical shape. A guide portion 5 is provided on the side surface 44 of the weight portion 4 on the rail portion 23 side. The guide portion 5 is combined with the rail portion 23.

  Specifically, the rail portion 23 is erected so as to be orthogonal to the upper surface of the flat base portion 22. And the guide part 5 which becomes movable in the up-down direction (vertical direction) with respect to this rail part 23 is assembled | attached.

  Moreover, the guide part 5 has a function which restrict | limits the weight part 4 swinging to the pile P side or the rail part 23 side. That is, the rail part 23 and the guide part 5 are provided so that the weight part 4 supported by the spring part 3 can move without receiving resistance only in the vertical direction (vertical direction).

  Further, a laser displacement meter 6 is attached to the side surface 43 of the weight portion 4 on the pile P side. The laser displacement meter 6 is attached so that the laser beam is irradiated downward.

  On the other hand, the reflection plate 61 of the laser displacement meter 6 is attached to the side surface P2 of the pile P on the displacement measuring device 1 side. The reflecting plate 61 projects in a direction substantially orthogonal to the side surface P2.

  The laser displacement meter 6 is disposed above the reflection plate 61 and irradiates the lower reflection plate 61 with laser light. The laser light reflected by the reflecting plate 61 is incident on a light receiving lens (not shown) of the laser displacement meter 6.

  The laser displacement meter 6 measures the displacement amount by a triangulation method using triangulation. As described above, when the laser displacement meter 6 is installed, the amount of displacement of the reflector 61 in the vertical direction (vertical direction) can be measured.

  The amount of displacement of the reflector 61 in the vertical direction can be the amount of displacement of the pile P to which the reflector 61 is attached. When the laser displacement meter 6 is installed so that the laser beam is irradiated upward, the reflection plate 61 projects from the side surface P2 above the laser displacement meter 6.

  On the other hand, the accelerometer 8 includes an acceleration sensor. When the weight 4 starts moving, the acceleration is detected by the acceleration sensor. And the displacement amount of the weight part 4 is computable by integrating the detected acceleration twice.

  Next, a method for measuring the displacement of the pile P using the displacement measuring device 1 of the present embodiment will be described, and the operation of the displacement measuring device 1 will be described.

  First, as shown in FIG. 1, the displacement measuring device 1 is installed at a position adjacent to the pile P. Since this position is a position where vibration generated when the pile P is hit is propagated through the ground G, it is normally a position that does not become a fixed point.

  The displacement measuring device 1 is installed by adjusting the tripod portion 21 so that the flat base portion 22 is horizontal. Further, the height of the flat base portion 22 is adjusted by the tripod portion 21 so that the laser displacement meter 6 attached to the side surface 43 of the weight portion 4 is disposed directly above the reflecting plate 61.

  Thus, after installing the displacement measuring apparatus 1, the weight W is dropped toward the pile head P1. When the pile head P1 is hit by the dropped weight W, displacement (displacement amount δ) occurs in the pile P as shown in the upper part of FIG.

  The displacement (displacement amount δ) of the pile P starts immediately after hitting (t = 0) and converges by repeating subsidence and rebound. On the other hand, as shown in the lower part of FIG. 2, the displacement of the weight portion 4 starts after the displacement of the pile P by a time t1.

  This is because, even when vibration due to impact propagates to the support base part 2, the weight part 4 supported by the spring part 3 so as to be freely swingable tries to maintain a stationary state by the law of inertia, and thus starts to move with a delay of time t1. by.

  The laser displacement meter 6 measures the relative displacement in the vertical direction (vertical direction) generated between the side surface 43 of the weight portion 4 and the side surface P2 of the pile P, but before the displacement of the weight portion 4 occurs. The measured value can be regarded as the absolute displacement of the pile P.

  As described above, the loading time of the rapid loading test is about 0.05 to 0.2 seconds, and the loading time of the impact loading test is about 0.01 to 0.02 seconds. For this reason, it is only necessary that the weight 4 can be kept stationary for at least this loading time.

  The period T of the amplitude of the weight portion 4 can be calculated by the following equation.

T = 2π√ (m / k)
Here, m represents the mass of the weight portion 4, and k represents the spring constant of the spring portion 3.

  And it is thought that the time until the movement of the weight part 4 becomes longer as the period T becomes longer. The time t1 is considered to be about T / 2.

  For this reason, by adjusting the mass m of the weight part 4 and the spring constant k of the spring part 3, if the period T of the amplitude of the weight part 4 is set to a long period, the time until the movement of the weight part 4 is lengthened. Can do.

  For example, by setting the period T to about 2 to 3 seconds, the weight portion 4 can be kept stationary during the loading time (1 second or less) of the rapid loading test and the impact loading test. It should be noted that the time for which the weight portion 4 is kept stationary (the time until the weight portion 4 starts to move) may be about 0.5 seconds.

  The period T can be arbitrarily set from the relationship with the ease of handling of the displacement measuring apparatus 1 and the like. For example, when the weight of the weight portion 4 may be increased, the displacement measuring device 1 having a period T of about 10 seconds can be manufactured.

  The displacement measuring device 1 of the present embodiment configured as described above includes a support base 2 that is installed separately from the pile P, and a spring portion 3 and a weight portion 4 that are connected thereto. And the relative displacement which generate | occur | produces between the weight part 4 and the pile P is measured with the laser type displacement meter 6. FIG.

  Here, the weight part 4 supported by the support base part 2 through the spring part 3 so as to be freely swingable tends to stop at the original position by inertia force even if the support base part 2 vibrates. Start of movement is delayed. Therefore, the relative displacement measured by the laser displacement meter 6 until the weight portion 4 starts to move can be regarded as the absolute displacement of the pile P.

  For this reason, even when the displacement measuring device 1 is installed at a point affected by the impact of the pile P, the displacement amount generated when the pile P is impacted only by the laser displacement meter 6 should be measured. Can do.

  Further, by adjusting the spring constant k of the spring part 3 and the mass m of the weight part 4, the period T with which the weight part 4 swings can be easily set to a desired long period. In particular, if the time until the start of movement due to vibration is set to 0.5 seconds or longer by setting the period T to be a long period, the displacement of the structure is sufficiently before the weight 4 starts moving in the impact loading test or the rapid loading test. The amount can be measured.

  Furthermore, if the period T in which the weight part 4 swings is set to a long period of 2 seconds or more, it is possible to secure a time of 1 second or more until the weight part 4 starts moving. The displacement amount of the pile P for a while can be measured.

  On the other hand, by attaching the accelerometer 8 to the weight part 4 so that the acceleration of the weight part 4 can be detected, the value measured by the laser displacement meter 6 after the weight part 4 starts moving can be used.

  That is, if the movement of the weight part 4 is detected by the accelerometer 8 and the detected acceleration is integrated twice, the displacement amount of the weight part 4 can be calculated. And the absolute displacement of the pile P can be calculated | required by adding or subtracting the calculated displacement amount of the weight part 4 to the measured value by the laser displacement meter 6. FIG.

  By attaching the accelerometer 8 to the weight part 4 in this way, it is not necessary to adjust the mass m of the weight part 4 or the spring constant k of the spring part 3, or the time taken from loading that cannot be dealt with only by adjustment. The absolute displacement of the pile P in the band (time period after the weight portion 4 starts to move) can also be calculated.

  Furthermore, if it is the displacement measuring apparatus 1 installed on the ground G as a separate body instead of being directly attached to the pile P, it is possible to easily increase the period T by increasing the weight 4.

  In addition, since the displacement measuring device 1 installed on the ground G as a separate body does not receive impact force due to impact, the laser displacement meter 6 and the accelerometer 8 are less likely to fail due to impact force due to impact. .

  Such a displacement measuring apparatus 1 has a lower end 31 of a spring portion 3 fixed to a flat base portion 22 of a support base portion 2 and a weight portion 4 connected to the lower end 31, and a rail portion 23 standing on the flat base portion 22. By providing the weight part 4 with the guide part 5 that can move in the vertical direction, it can be easily manufactured.

  Further, by using the non-contact type laser displacement meter 6 to measure the relative displacement generated between the side surface 43 of the weight part 4 and the side surface P2 of the pile P, a large impact or repeated impact is performed. However, the apparatus can measure the displacement with high accuracy without being damaged.

  Hereinafter, a displacement measuring apparatus 1A of Example 1 different from the displacement measuring apparatus 1 of the above-described embodiment will be described with reference to FIG. The description of the same or equivalent parts as the contents described in the above embodiment will be described with the same terms or the same reference numerals.

  The weight part 4 described in the above embodiment is configured to be placed on the spring part 3, but in Example 1, a displacement measuring device 1A having a structure in which the weight part 4 is suspended by the spring part 3 will be described. .

  This displacement measuring apparatus 1A includes a support base 2A installed separately from the pile P, a spring part 3 suspended from the support base 2A, a weight part 4 suspended from the spring part 3, and a weight part 4 A laser displacement meter 6 that measures the relative displacement generated between the side surface 43 of the pile P and the side surface P2 of the pile P, and an accelerometer 8 that is attached to the side surface 43 of the weight portion 4 directly above the laser displacement meter 6. Mainly composed.

  The support base 2A includes a tripod portion 21 installed on the surface of the ground G, a flat base portion 22 provided on the top of the tripod portion 21, a post portion 24 that stands on the upper surface of the flat base portion 22 and extends upward, It is mainly comprised by the overhang | projection part 25 projected toward the pile P from the upper part of the part 24. FIG.

  The column part 24 is erected so as to be orthogonal to the upper surface of the flat table part 22. In addition, an overhang portion 25 is provided at the upper end of the column portion 24 so as to be orthogonal to the column portion 24 and parallel to the flat table portion 22.

  The upper end 32 of the spring portion 3 is fixed to the lower surface of the overhang portion 25, and the lower end 31 is connected to the upper surface 42 of the weight portion 4. In a state in which the weight portion 4 is stationary, a space larger than the amplitude of the weight portion 4 is secured between the bottom surface 41 of the weight portion 4 and the upper surface of the flat base portion 22.

  As described above, the support base 2A is provided with the support column 24 extending upward and the overhang 25 extending from the upper portion thereof, and the weight 4 is suspended from the overhang 25 by the spring 3 so as to freely swing. Even if it exists, it can be manufactured easily.

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Hereinafter, a displacement measuring device 1B according to a second embodiment different from the displacement measuring device 1 according to the above-described embodiment and the displacement measuring device 1A according to the first embodiment will be described with reference to FIG. In addition, about the description of the part same or equivalent to the content demonstrated in the said embodiment or Example 1, it attaches | subjects and demonstrates the same term or the same code | symbol.

  In the embodiment and Example 1, the case where the laser displacement meter 6 is used as the displacement meter has been described. In Example 2, a displacement measuring device 1B that uses the contact displacement meter 7 as the displacement meter will be described. .

  Since the displacement measuring device 1B of the second embodiment is the same as the displacement measuring device 1 described in the above embodiment except for the contact displacement meter 7, the overlapping description is omitted.

  In FIG. 4, the accelerometer 8 is attached to the upper surface 42 of the weight portion 4. However, the present invention is not limited to this, and the accelerometer 8 can also be attached to an empty position on the side surface 43.

  The contact displacement meter 7 measures the relative displacement in the vertical direction (vertical direction) generated between the side surface 43 of the weight portion 4 and the side surface P2 of the pile P as a displacement amount. The contact displacement meter 7 is mainly configured by a plurality of wheels 72,... For stably running the side surface P2 of the pile P in the vertical direction and measurement wheels 71 for measuring the moving distance.

  The measuring wheel 71 has a built-in sensor for measuring a rotation angle such as a rotary encoder, and the moving distance of the measuring wheel 71 calculated based on the measured rotation angle is a displacement amount.

  4, the contact-type displacement meter 7 is attached to the side surface 43 on the pile P side of the weight portion 4, and the measuring wheel 71 and the wheels 72,... Are in contact with the side surface P2 of the pile P. On the other hand, the contact-type displacement meter 7 can be attached to the side surface P2 on the side of the weight 4 of the pile P so that the measuring wheel 71 and the wheels 72,. .

  Thus, the displacement measuring device 1B can be easily manufactured by using the contact displacement meter 7 that measures the relative displacement generated between the side surface 43 of the weight part 4 and the side surface P2 of the pile P as a displacement meter. be able to.

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Hereinafter, a displacement measuring device according to a third embodiment different from the displacement measuring device 1 according to the above-described embodiment and the displacement measuring devices 1A and 1B according to the first and second embodiments will be described. Note that the description of the same or equivalent parts as those described in the embodiment or examples will be given with the same terms or the same reference numerals.

  In the embodiment and the first and second embodiments, the case where the weight portion 4 is supported by the spring portion 3 so as to freely swing is described. However, in the third embodiment, the weight portion 4 is supported by the actuator portion instead of the spring portion 3. A displacement measuring apparatus to be operated will be described.

  The actuator unit includes a servo motor, and the length can be adjusted by driving the servo motor. The servo motor is controlled based on a signal detected by the accelerometer 8.

  That is, when the weight portion 4 immediately after hitting the pile P is stationary, the acceleration detected by the accelerometer 8 is 0, so the servo motor is not driven and the length of the actuator portion does not change.

  On the other hand, if the weight 4 starts to move after a while, the accelerometer 8 detects the acceleration, so that the displacement amount of the weight 4 can be calculated. Therefore, by driving the servo motor and changing the length of the actuator portion in a direction that cancels out the displacement amount of the weight portion 4, the weight portion 4 can be fixed at a position where it was initially stationary.

  With the configuration of the displacement measuring apparatus of Example 3 as described above, the configuration of the weight portion 4 and the support base portions 2 and 2A can be reduced in size. Further, when the free amplitude is used, the weight 4 can remain at the initial position (fixed position) even after the time that the weight 4 starts to move, if the actuator is used.

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to the embodiment and the example, and the design change is within a range not departing from the gist of the present invention. Are included in the present invention.

  For example, in the said embodiment and Example, although the case where the structure was the pile P was demonstrated, it is not limited to this, Even if a steel sheet pile or a support | pillar is a structure, the displacement measuring apparatus 1 of this invention , 1A, 1B can be used.

  Moreover, in the said embodiment and Example 1, although it was set as the structure which measures the amount of displacements of an up-down direction by irradiating the laser beam of the laser type displacement meter 6 toward the reflecting plate 61, it is limited to this. Instead, the tip of a dial gauge, which is a contact displacement meter, can be pressed against the reflecting plate 61 to measure the amount of displacement in the vertical direction.

DESCRIPTION OF SYMBOLS 1 Displacement measuring device 2 Support base part 22 Flat base part 23 Rail part (columnar part)
3 Spring portion 31 Lower end 32 Upper end 4 Weight portion 41 Bottom surface 42 Upper surface 43 Side surface 5 Guide portion 6 Laser displacement meter (displacement meter)
61 Reflector 1A Displacement measuring device 2A Support base 24 Support column 25 Overhang 1B Displacement measuring device 7 Contact displacement meter (displacement meter)
8 Accelerometer G Ground P Pile (Structure)
P2 Side T Period δ Displacement

Claims (9)

A displacement measuring device that measures the amount of displacement generated when striking a structure to be driven into the ground,
A support base installed separately from the structure;
A spring portion connected to the support base portion;
A weight portion that is supported by the spring portion so as to freely swing,
A displacement measuring apparatus comprising: a displacement meter that measures a relative displacement generated between a side surface of the weight portion and a side surface of the structure.   2. The displacement according to claim 1, wherein the spring portion and the weight portion are adjusted so that a time until the movement starts due to vibration generated in the surrounding ground when the structure to be driven into the ground is hit is increased. measuring device.   The displacement measuring apparatus according to claim 2, wherein a time until the movement starts due to the vibration is adjusted to be 0.5 seconds or longer. The support base part includes a flat base part and a columnar part that stands on the flat base part,
The spring part has a lower end fixed to the flat base part and an upper end connected to the bottom surface of the weight part,
The displacement measuring device according to any one of claims 1 to 3, wherein the weight portion is provided with a guide portion that can freely move in a vertical direction with respect to the columnar portion. The support base portion includes a support column portion that extends upward, and an overhang portion that protrudes from the upper portion of the support column portion toward the structure,
4. The displacement measuring device according to claim 1, wherein an upper end of the spring part is fixed to the projecting part and a lower end is connected to an upper surface of the weight part. 5.   A laser displacement meter is attached to the side surface of the weight portion so that the laser beam is irradiated in one of the vertical directions as the displacement meter, and the laser beam is reflected from the side surface of the structure. The displacement measuring apparatus according to claim 1, wherein the reflecting plate is projected.   A contact-type displacement meter that measures a relative displacement generated between the side surface of the weight portion and the side surface of the structure is attached to the side surface of the weight portion or the side surface of the structure as the displacement meter. The displacement measuring device according to any one of claims 1 to 5.   The displacement measuring device according to any one of claims 1 to 7, wherein an accelerometer is attached to the weight portion. A displacement measuring device that measures the amount of displacement generated when striking a structure to be driven into the ground,
A support base installed separately from the structure;
An actuator part connected to the support base part;
A weight portion supported by the actuator portion;
A displacement meter for measuring a relative displacement generated between a side surface of the weight part and a side surface of the structure;
An accelerometer attached to the weight,
The displacement measuring device, wherein the weight portion is fixed at a fixed position by the actuator portion controlled based on a signal detected by the accelerometer.