JP6528037B2 - Displacement measuring device - Google Patents

Description

  The present invention relates to a displacement measurement apparatus used when striking a supporting force or the like by striking a structure such as a pile with a freely dropped weight or hammer.

  There is known a strikeout control method of a pile to determine whether or not the tip of the pile reaches the support layer by measuring the displacement amount of the pile when striking the pile head with a weight or hydraulic hammer or the like. (Refer to patent documents 1-3 etc.).

  Moreover, the load test method of piles, such as a rapid load test which measures the bearing capacity of a pile, is known by measuring the load and the displacement of a pile at the time of hitting a pile head with a weight (patented patent) Reference 4).

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

Patent No. 2700397 gazette Japanese Utility Model Application Publication No. 4-30410 Unexamined-Japanese-Patent No. 5-25826 JP 2002-303570 A

  However, as described in Patent Literature 1-3, when it is difficult to install a pile displacement measuring device at a fixed point at a pile driving site due to limitations such as the narrowness of a site and the presence of an obstacle, etc. The reality is that there are many.

  For this reason, in patent document 1, the displacement is measured by attaching a displacement measuring device utilizing the inertia force of the weight to the side surface of the pile. In this displacement measuring device, a weight is suspended by a combination of a spring and a dashpot in the inside of a case fixed to the side of a pile.

  Then, the relative displacement between the weight and the pile (case) is measured by the potentiometer, and the absolute displacement of the weight itself is calculated from the detection value of the acceleration sensor.

  That is, when the 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 stay in its original position by inertia force and moves even in a high frequency range. Vibrates at a low frequency cycle (1 / several seconds) without following the movement of.

  For this reason, in the cited reference 1, the movement of the weight is detected by the acceleration sensor, and the acceleration is integrated twice to calculate the amount of displacement of the weight and add or subtract to or from the measurement value of the potion meter.

  Thus, in the displacement measuring device of Patent Document 1, since the weight is attached to the side of the pile, the movement of the weight is quick (1 / several seconds), and the two measuring instruments of the potentiometer and the accelerometer are also susceptible to shocks. There is a risk of failure as it is placed under the environment.

  Therefore, it is an object of the present invention to provide a displacement measuring device capable of measuring a displacement amount with high accuracy and being hard to break even when installed at a point affected by the impact of a structure. And

  In order to achieve the above object, the displacement measuring device of the present invention is a displacement measuring device for measuring a displacement amount generated when striking a structure driven into the ground, and is installed apart from the structure. Supporting portion, a spring portion connected to the supporting portion, a weight portion supported by the spring portion so as to be capable of swinging, and a relative position generated between the side surface of the weight portion and the side surface of the structure And a displacement gauge for measuring displacement.

  Here, it is preferable that the spring portion and the weight portion be adjusted such that the time until the movement due to the vibration generated in the surrounding ground becomes long when the structure driven into the ground is hit. For example, the time until the movement due to the vibration is adjusted to be 0.5 seconds or more.

  Further, the support base portion includes a flat base portion and a columnar portion erected on the flat base portion, and a lower end of the spring portion is fixed to the flat base portion and an upper end is connected to a bottom surface of the weight portion. The weight portion may be provided with a guide portion which can freely move in the vertical direction with respect to the columnar portion.

  On the other hand, the support base portion includes a support portion extending upward, and an overhang portion extending toward the structure from an upper portion of the support portion, and an upper end of the spring portion is fixed to the overhang portion. And 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 laser beam is irradiated in any one direction in the vertical direction as the displacement meter, and the laser beam is attached from the side surface of the structure. It can be set as the structure by which the reflecting plate to reflect is projected.

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

  Furthermore, an accelerometer may be attached to the weight portion. Moreover, it is a displacement measuring device which measures the displacement amount which generate | occur | produces when striking the structure driven into the ground, Comprising: It is connected to the support stand part spaced apart from the said structure, and the said support stand. An actuator unit, a weight unit supported by the actuator unit, a displacement gauge for measuring a relative displacement generated between a side surface of the weight unit and a side surface of the structure, and an accelerometer mounted on the weight unit The weight portion may be fixed in a fixed position by the actuator portion controlled based on a signal detected by the accelerometer.

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

  Here, since the weight portion supported on the support base portion via the spring portion so as to be able to oscillate is trying to stay at the original position by the inertial force even if the support base portion vibrates, the start of movement is delayed compared to the structure. Therefore, the relative displacement measured by the displacement gauge before the weight starts moving can be regarded as the absolute displacement of the structure.

  For this reason, even when the displacement measuring device is installed at a point affected by the impact of the structure, the impact force due to the impact is not received. Can.

  Further, by adjusting the spring constant of the spring portion and the mass of the weight portion, it is possible to easily lengthen the time until the movement of the weight portion due to the vibration generated at the time of striking. In particular, if the time until the start of movement by 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, a rapid loading test, or the like.

  In such a displacement measuring device, the lower end of the spring portion is fixed to the flat base portion of the support base portion and the weight portion is connected thereon, and vertical movement is possible with respect to the columnar portion erected on the flat base portion. It can manufacture easily by providing the following guide part in a weight part.

  Further, even if the support base portion is provided with the post portion extending upward and the overhang portion projecting from the upper portion, the weight portion can be easily manufactured even if the weight portion is suspended by the spring portion from the overhang portion. .

  Furthermore, using a noncontact laser displacement meter to measure the relative displacement generated between the side surface of the weight portion and the side surface of the structure damages even a large impact or repeated impact It is possible to make a device with high accuracy and high accuracy.

  Moreover, a displacement measuring device can be easily manufactured also by using a contact-type displacement gauge which measures relative displacement generated between the side surface of the weight portion and the side surface of the structure as the displacement gauge.

  Then, by attaching an accelerometer to the weight portion so as to detect the acceleration, the absolute displacement of the structure can be calculated by correction even after the weight portion starts moving. As a result, it becomes unnecessary to adjust the weight portion and the spring portion, and it becomes possible to measure the absolute displacement of the time zone which can not be dealt with only by the adjustment.

  Furthermore, the configuration of the weight portion or the support base portion, as long as the weight portion is supported by the actuator portion and the actuator portion is controlled to be fixed at a fixed position based on a signal detected by the accelerometer. Can be miniaturized. In addition, it is also possible to fix the weight portion at the initial position (fixed position) for a long time.

It is an explanatory view showing composition of a displacement measuring device of an embodiment of the invention. It is the graph which showed the relation of displacement and time, in order to explain the gap of the movement start of a pile and a weight part. FIG. 2 is an explanatory view showing a configuration of a displacement measuring device of Example 1. FIG. 7 is an explanatory view showing a configuration of a displacement measuring device of Example 2.

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

  In the present embodiment, a case will be described where the pile head P1 of the pile P as a structural body is hit with a freely dropped weight W or hydraulic hammer or the like. Such a strike of the pile head P1 is performed not only at the time of driving the pile P, but also at the time of a rapid loading test, an impact loading test, and the like.

  The rapid loading test is a test method for pile P devised to eliminate the drawbacks of static loading test and impact loading test, and according to this method, the loading time is about 10 times that of impact loading test, 0.05 to 0.2 seconds By setting the degree, it is possible to eliminate the influence of elastic wave propagation and to obtain highly reliable test results close to the static loading test.

  In the rapid loading test, a shock absorber (not shown) such as rubber is placed on the pile head P1 via a load meter (not shown), and the weight W is allowed to freely fall on the pile P to be hit. By interposing the buffer material between the weight W and the pile head P1 as described above, the loading time can be extended.

  On the other hand, when the weight W is dropped directly on the pile head P1, an 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 supporting force of the pile P based on the one-dimensional wave theory from the strain and acceleration generated in the pile head P1 in a short time.

  In these tests, the magnitude of the 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 at the pile head P1.

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

  The displacement measuring device 1 includes a support base 2 installed apart from the pile P, a spring 3 connected to the support base 2, and a weight 4 supported by the spring 3 in a swingable manner. It is mainly comprised by the laser type displacement gauge 6 as a displacement gauge which measures the relative displacement generate | occur | produced between the side 43 of the weight part 4, and the side P2 of the pile P. As shown in FIG.

  Further, an accelerometer 8 is attached to a side surface 43 of the weight portion 4 which is the periphery of the laser displacement meter 6.

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

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

  For the spring portion 3, for example, a helical 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, for the weight portion 4, a member having a known mass (m) is used. The weight 4 is made of a member having such a weight that it can stay in the initial position more than a desired time according to the law of inertia even if the support base 2 vibrates.

  The weight 4 is formed in, for example, a square pole shape or a cylindrical shape. The guide portion 5 is provided on the side surface 44 on the side of the rail portion 23 of the weight portion 4. 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. Then, the guide portion 5 is assembled such that movement in the vertical direction (vertical direction) is free with respect to the rail portion 23.

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

  Furthermore, the laser displacement meter 6 is attached to the side surface 43 on the pile P side of the weight portion 4. The laser displacement meter 6 is mounted such that the laser light is directed downward.

  On the other hand, the reflection plate 61 of the laser type displacement gauge 6 is attached to the side surface P2 on the displacement measurement device 1 side of the pile P. The reflection 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 the laser light is emitted toward the lower reflection plate 61. The laser beam reflected by the reflection plate 61 is incident on a light receiving lens (not shown) of the laser displacement meter 6.

  The laser displacement meter 6 measures the amount of displacement by a triangular distance measurement method to which triangulation is applied. As described above, when the laser displacement meter 6 is installed, the amount of displacement of the reflection plate 61 in the vertical direction (vertical direction) can be measured.

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

  On the other hand, the accelerometer 8 incorporates an acceleration sensor. When the weight 4 starts to move, the acceleration sensor detects the acceleration. Then, the displacement amount of the weight 4 can be calculated by integrating the detected acceleration twice.

  Next, a method of 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. This position is a position at which the vibration generated when striking the pile P propagates through the ground G, and therefore is a position that does not normally become an immobile point.

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

  After installing the displacement measuring device 1 in this manner, 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 from immediately after the impact (t = 0), converges repeatedly by sinking and rebounding. On the other hand, as shown in the lower part of FIG. 2, the displacement of the weight portion 4 starts behind the displacement of the pile P by time t1.

  This is because, even if the vibration caused by the impact is transmitted to the support base 2, the weight 4 supported by the spring 3 so as to be able to swing freely tries to maintain the stationary state according to the law of inertia. 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 4 and the side P2 of the pile P, but before the displacement occurs in the weight 4 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. Therefore, it is sufficient if the weight 4 can be made stationary at least during this loading time.

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

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

  And it is thought that the time to the movement start of the weight part 4 becomes long, so that this period T becomes long. The time t1 is considered to be about T / 2.

  Therefore, if the period T of the amplitude of the weight 4 is made long by adjusting the mass m of the weight 4 and the spring constant k of the spring 3, the time until the movement of the weight 4 becomes long can be extended. Can.

  For example, by setting the cycle T to about 2 to 3 seconds, the weight 4 can be kept stationary within the loading time (1 second or less) of the rapid loading test and the shock loading test. The time for which the weight 4 is kept still (the time until the weight 4 starts to move) may be about 0.5 seconds.

  The period T can be set arbitrarily from the relationship with the ease of handling of the displacement measuring device 1 or the like. For example, in the case where the weight of the weight 4 may be increased, the displacement measurement device 1 in which the cycle T is about 10 seconds can be manufactured.

  The displacement measuring device 1 of this embodiment configured in this manner includes the support base 2 installed apart from the pile P, and the spring 3 and the weight 4 connected thereto. Then, the relative displacement generated between the weight 4 and the pile P is measured by the laser displacement meter 6.

  Here, the weight portion 4 supported by the support portion 2 via the spring portion 3 so as to be able to oscillate is intended to be stopped at the original position by the inertia force even if the support portion 2 vibrates. Movement is delayed. Therefore, the relative displacement measured by the laser displacement meter 6 before the weight 4 starts moving can be regarded as the absolute displacement of the pile P.

  Therefore, 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 struck with only the laser displacement meter 6 is measured. Can.

  Further, by adjusting the spring constant k of the spring portion 3 and the mass m of the weight portion 4, it is possible to easily set the cycle T of the weight portion 4 to a desired long period. In particular, if the time until the movement due to vibration is set to 0.5 seconds or more by setting the cycle T to a long period, the displacement of the structure is sufficiently performed before the weight portion 4 starts to move in the impact loading test or the rapid loading test. The quantity can be measured.

  Furthermore, if the oscillating cycle T of the weight 4 is set to a long cycle of 2 seconds or more, a time of 1 second or more can be secured before the weight 4 starts to move, so after loading such as rebound etc. The displacement amount of the pile P can be measured for a while.

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

  That is, the displacement of the weight 4 can be calculated by detecting the movement of the weight 4 by the accelerometer 8 and integrating the detected acceleration twice. The absolute displacement of the pile P can be obtained by adding or subtracting the calculated displacement amount of the weight 4 to or from the measurement value of the laser displacement meter 6.

  By attaching the accelerometer 8 to the weight 4 in this manner, it becomes unnecessary to adjust the mass m of the weight 4 and the spring constant k of the spring 3 or the time taken from the loading which can not be coped with by adjustment alone. It also becomes possible to calculate the absolute displacement of the pile P of the band (the time zone after the weight 4 has started to move).

  Furthermore, in the case of the displacement measurement device 1 installed on the ground G separately as a separate body rather than directly attached to the pile P, it is possible to easily enlarge the weight 4 and lengthen the cycle T.

  Moreover, if it is displacement measurement device 1 installed separately on ground G as a separate body, since it does not receive the impact force by a hit, it becomes difficult to break laser type displacement meter 6 and accelerometer 8 by the impact force by a hit etc. .

  Such a displacement measuring device 1 fixes the lower end 31 of the spring portion 3 to the flat base portion 22 of the support base portion 2 and connects the weight portion 4 thereon, with respect to the rail portion 23 erected on the flat base portion 22 By providing the weight portion 4 with the guide portion 5 which can freely move in the vertical direction, it can be easily manufactured.

  Moreover, in order to measure the relative displacement generated between the side surface 43 of the weight 4 and the side surface P2 of the pile P, a large impact or repeated impact is performed by using the noncontact laser displacement meter 6. Even if it does not damage, it can be set as the apparatus which can measure the amount of displacement with high precision.

  Hereinafter, a displacement measuring device 1A of a first embodiment different from the displacement measuring device 1 of the above-described embodiment will be described with reference to FIG. 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 portion 4 described in the above embodiment is configured to be placed on the spring portion 3, but in the first embodiment, the displacement measurement device 1A configured to suspend the weight portion 4 by the spring portion 3 will be described. .

  The displacement measuring device 1A includes a support base 2A installed separately from the pile P, a spring 3 suspended from the support base 2A, a weight 4 suspended from the spring 3, and a weight 4 Laser displacement meter 6 for measuring the relative displacement generated between the side surface 43 of the pile P and the side surface P2 of the pile P, and the accelerometer 8 attached to the side surface 43 of the weight 4 directly above the laser displacement meter 6 Mainly composed.

  The support base portion 2A includes a tripod portion 21 installed on the surface of the ground G, a flat base portion 22 provided on the upper portion of the tripod portion 21, a support portion 24 erected on the upper surface of the flat support portion 22 and extending upward It is mainly comprised by the overhang part 25 projected toward the pile P from the upper part of the part 24. As shown in FIG.

  The support 24 is erected perpendicular to the upper surface of the flat base 22. Further, an overhanging portion 25 is provided on the upper end of the support portion 24 so as to be orthogonal to the support portion 24 and parallel to the flat base portion 22.

  The upper end 32 of the spring portion 3 is fixed to the lower surface of the overhanging portion 25, and the lower end 31 is connected to the upper surface 42 of the weight portion 4. In the state where the weight 4 is at rest, a separation equal to or greater than the amplitude of the weight 4 is secured between the bottom surface 41 of the weight 4 and the upper surface of the flat base 22.

  As described above, the support base portion 2A is provided with the post portion 24 extending upward and the overhang portion 25 projecting from the upper portion, and the weight portion 4 is suspended from the overhang portion 25 by the spring portion 3 in an swingable manner. Even if there is, it can be easily manufactured.

  In addition, about another structure and an effect, since it is substantially the same as the said embodiment or another Example, description is abbreviate | 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 same thru | or equivalent part as the content demonstrated in the said embodiment or Example 1, the same term or the same code | symbol is attached | subjected and demonstrated.

  Although the case where the laser type displacement meter 6 was used as a displacement meter was described in the said embodiment and Example 1, in Example 2, the displacement measurement apparatus 1B which uses the contact type displacement meter 7 as a displacement meter is demonstrated. .

  The displacement measurement apparatus 1B of the second embodiment is the same as the displacement measurement apparatus 1 described in the above embodiment except for the configuration of the contact type displacement meter 7. Therefore, the redundant description will be omitted.

  Although the accelerometer 8 is attached to the upper surface 42 of the weight 4 in FIG. 4, the present invention is not limited to this, and the accelerometer 8 may be attached to an open position of the side surface 43.

  The contact type displacement meter 7 measures the relative displacement in the vertical direction (vertical direction) generated between the side surface 43 of the weight 4 and the side surface P2 of the pile P as a displacement amount. The contact type displacement meter 7 mainly includes a plurality of wheels 72,... For stably traveling the side surface P2 of the pile P in the vertical direction, and a measuring wheel 71 for measuring a movement distance.

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

  In FIG. 4, the contact type displacement meter 7 is attached to the side surface 43 on the pile P side of the weight 4, and the measuring wheel 71 and the wheels 72,... Are in contact with the side surface P2 of the pile P. Alternatively, the contact displacement meter 7 may be attached to the side surface P2 of the pile P on the weight 4 side, and the measuring wheel 71 and the wheels 72 may be in contact with the side surface 43 of the weight 4. .

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

  In addition, about another structure and an effect, since it is substantially the same as the said embodiment or another Example, description is abbreviate | omitted.

  Hereinafter, a displacement measurement apparatus according to a third embodiment different from the displacement measurement apparatus 1 according to the above-described embodiment and the displacement measurement apparatuses 1A and 1B according to the first and second embodiments will be described. The same or equivalent parts as the contents described in the embodiment or the example will be described with the same terms or the same reference numerals.

  In the embodiment and Examples 1 and 2 described above, the case where the weight 4 is supported by the spring 3 so as to be able to swing freely is described. However, in the example 3, the weight 4 is supported by the actuator instead of the spring 3. The displacement measuring device to be used will be described.

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

  That is, when the weight 4 immediately after the strike of the stake P is stationary, the acceleration detected by the accelerometer 8 is zero, so the servomotor is not driven and the length of the actuator does not change.

  On the other hand, when the weight portion 4 tries to move for a while after impact, the accelerometer 8 detects the acceleration, so that the displacement amount of the weight portion 4 can be calculated. Therefore, by driving the servomotor and changing the length of the actuator portion in the direction in which the displacement amount of the weight portion 4 is offset, the weight portion 4 can be fixed at the position at which it initially stopped.

  With the configuration of the displacement measuring device according to the third embodiment, it is possible to miniaturize the configuration of the weight 4 and the support bases 2 and 2A. In addition, in the case of using the actuator unit, the weight 4 can be kept at the initial position (fixed position) even after the time for the weight 4 to move out has elapsed in the case of free amplitude.

  In addition, about another structure and an effect, since it is substantially the same as the said embodiment or another Example, description is abbreviate | omitted.

  As mentioned above, although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to the embodiment and the example, and a design change which does not deviate from the scope of the present invention. Is included in the present invention.

  For example, although the case where the structure is pile P was explained in the above-mentioned embodiment and an example, it is not limited to this, and even if a steel sheet pile and a pillar are structures, displacement measurement device 1 of the present invention , 1A, 1B can be used.

  In the embodiment and the first embodiment, the laser light of the laser displacement meter 6 is directed to the reflecting plate 61 to measure the displacement amount in the vertical direction, but the present invention is limited thereto. Instead, the tip of a dial gauge, which is a contact displacement meter, may be pressed against the reflection plate 61 to measure the displacement in the vertical direction.

Reference Signs List 1 displacement measuring device 2 support base 22 flat base 23 rail (columnar part)
Reference Signs List 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 Reflecting plate 1A displacement measuring device 2A support base portion 24 support portion 25 overhanging portion 1B displacement measuring device 7 contact displacement gauge (displacement gauge)
8 accelerometer G ground P pile (structure)
P2 Side surface T period δ displacement

Claims (8)

A displacement measuring device for measuring the amount of displacement generated when a structure driven into the ground is struck,
A support base installed apart from the structure;
A spring portion connected to the support portion;
A weight portion which is swingably supported by the spring portion;
A displacement measuring device comprising: a displacement gauge for measuring a relative displacement generated between a side surface of the weight portion and a side surface of the structure. The spring portion and the weight portion are adjusted such that a time taken to move due to a vibration generated in the surrounding ground when striking a structure driven into the ground is adjusted to be 0.5 seconds or more. The displacement measuring device described in. The support portion includes a flat portion and a columnar portion erected on the flat portion.
The lower end of the spring portion is fixed to the flat base portion and the upper end is connected to the bottom surface of the weight portion.
The displacement measuring device according to claim 1 or 2 , wherein the weight portion is provided with a guide portion which can move in the vertical direction with respect to the columnar portion. The support base includes an upwardly extending support column, and an overhang extending toward the structure from an upper portion of the support column.
The displacement measuring device according to claim 1 or 2 , wherein the upper end of the spring portion is fixed to the projecting portion and the lower end is connected to the upper surface of the weight portion. A laser displacement gauge 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 gauge, and the laser beam is reflected from the side surface of the structure. The displacement measuring device according to any one of claims 1 to 4, wherein a reflecting plate is projected. A contact-type displacement gauge for measuring 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. The displacement measuring device according to any one of claims 1 to 4 , wherein The displacement measuring device according to any one of claims 1 to 6 , wherein an accelerometer is attached to the weight portion. A displacement measuring device for measuring the amount of displacement generated when a structure driven into the ground is struck,
A support base installed apart from the structure;
An actuator unit connected to the support base;
A weight portion supported by the actuator portion;
A displacement gauge that measures relative displacement generated between the side surface of the weight portion and the 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.