JP2005283361A - Method and apparatus for evaluating soundness degree of block-like structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for evaluating a soundness degree of a block-like structure, which can easily evaluate the soundness of a foundation when swelling. <P>SOLUTION: A sensor 7a is installed at the downstream side of the upper end of a bridge pier 1 and a sensor 7b is installed at the upstream side. The sensor 7 is connected to a computer 17 via a cable 15. The velocity, the acceleration, and so forth of the oscillation generated in the bridge pier 1 by a usual slight movement of the foundation 3 or the excitation force due to a stream of water are measured, using the sensor 7a and the sensor 7b. Next, a trajectory of the velocity of the bridge pier 1 in the vertical direction is displayed, and the soundness of the foundation degree of the bridge pier 1 is evaluated, from the shape of the trajectory. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a block structure soundness evaluation method and a block structure soundness evaluation apparatus.

  Block-like structures such as pier foundations may become unstable due to the influence of scouring due to water flow when the river is flooded. Conventionally, there has been a method in which a sensor is installed on a block-like structure such as a bridge pier and the soundness of the structure is determined based on a constant fine movement signal measured by the sensor.

  In order to determine the soundness level based on the continuous fine movement signal, values obtained as described in the following (1) to (3) were used. (1) The rocking depth and the amount of eccentricity of the pier are calculated from the Fourier spectrum values of the horizontal direction component and the vertical direction component of the microtremor signal (see, for example, Patent Document 1). (2) A numerical value indicating a correlation such as a correlation coefficient or a correlation contribution ratio of the vibration waveform of the horizontal direction component and the vertical direction component of the microtremor waveform at the same time is calculated (for example, see Patent Document 2). (3) The contribution ratio of the rocking vibration in the entire vibration is obtained from the horizontal component and the vertical component of the waveform of the fine movement, and the degree of the rocking vibration at an arbitrary position is determined by using the contribution ratio of the rocking vibration. (For example, refer to Patent Document 3).

Japanese Examined Patent Publication No. 7-1223 Japanese Patent No. 2731696 Japanese Patent No. 3078706

  However, the conventional method using constant tremor requires time and effort for data processing.

  The present invention has been made in view of such problems, and the object of the present invention is to provide a block-like structure soundness evaluation method and a block-like structure that can easily evaluate the soundness of the foundation during water increase. It is to provide a soundness evaluation device.

  The first invention for achieving the above-described object is the step (a) of acquiring behavior data of the block-like structure using sensors installed at two positions near the upper end of the block-like structure; A step (b) illustrating a trajectory of a specific vertical component based on behavior data, and a step (c) for evaluating the soundness of the foundation of the block-like structure from the shape of the trajectory. This is a method for evaluating the soundness of a block-like structure characterized by the following.

  A sensor is provided in the position which the upper end surface of a block-shaped structure opposes, for example. The block-like structure is, for example, a pier of a bridge built over a river. In this case, the opposing positions are the upstream side and the downstream side of the river. In the step (a), behavior data, that is, data such as the speed and acceleration of vibration generated in the structure due to the ground microtremor and the excitation force caused by the water flow are collected using a sensor. In the step (b), the trajectory of a specific vertical direction component (speed, acceleration, virtual displacement obtained from the speed, etc.) is illustrated based on the behavior data acquired by two sensors. Note that it is desirable to use the vertical velocity as the specific vertical component. At a process (c), the soundness degree at the time of the water increase of the foundation of a block-shaped structure is evaluated from the shape of a locus | trajectory.

  The second invention is installed at two locations near the upper end of the block-like structure, and the sensor for acquiring the behavior data of the block-like structure and the locus of the specific vertical component based on the behavior data are illustrated. And a means for evaluating the soundness of the foundation of the block-like structure based on the shape of the trajectory.

  A sensor is provided in the position which the upper end surface of a block-shaped structure opposes. The block-like structure is, for example, a pier of a bridge built over a river. In this case, the opposing positions are the upstream side and the downstream side of the river. The sensor collects behavior data, that is, data such as the speed and acceleration of vibration generated in the structure due to the microtremor of the ground or the excitation force caused by the water flow. The behavior data is sent to a computer or the like, and the computer displays a trajectory of a specific vertical component (speed, acceleration, virtual displacement obtained from the velocity, etc.) based on the behavior data, and from the shape of the trajectory, the structure Assess the soundness of the foundation of the water at the time of flooding. Note that it is desirable to use the vertical velocity as the specific vertical component.

  According to the soundness evaluation method for a block-like structure and the soundness evaluation apparatus for a block-like structure according to the present invention, the soundness of the foundation during water increase can be easily evaluated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an elevation view of a pier 1 in which a soundness evaluation device is installed. The pier 1 is supported by the ground 3 at the bottom of the river. A girder 9 is installed on the upper surface of the pier 1. When the pier 1 is of a railway bridge, a sleeper 11 is installed on the beam 9, and a bridge sidewalk 13 is provided on the side.

  The soundness evaluation apparatus includes two sensors 7, a cable 15, a computer 17, and the like. The cable 15 connects the sensor 7 and the computer 17. The sensors 7a and 7b are vibration sensors. When the river water 5 flows in the direction indicated by the arrow A, the sensor 7 a is installed on the downstream side of the upper end surface of the pier 1, and the sensor 7 b is installed on the upstream side of the upper end surface of the pier 1. The computer 17 is disposed on the bridge sidewalk 13.

  The soundness evaluation apparatus uses the sensor 7 to measure data relating to vibrations that occur in the pier 1 due to the constant fine movement of the ground 3 or the excitation force caused by the flow of water 5. The computer 17 acquires behavior data measured by the sensor 7 via the cable 15. Then, the trajectory of the vertical speed measured by the two sensors 7 is drawn, and the trajectory is displayed on the display device as necessary. Furthermore, from the shape of the trajectory, the soundness of the foundation of the pier 1 at the time of water increase is determined, and the determination result is displayed. In the determination using the trajectory, the angle, deflection width, and variation with respect to the trajectory axis are used as indices.

  FIG. 2 shows the result of a comparative experiment of vibration properties for a pier actually installed in a river. In the experiment shown in FIG. 2, the soundness evaluation apparatus as shown in FIG. 1 was installed on the pier, and the vibration properties were compared.

  Each figure in the upper part of Fig. 2 shows the situation around the foundation around the pier. FIG. 2A is an elevation view of a healthy pier 1a. FIG. 2B is an elevation view of the pier 1b in which the ground 3 is excavated so that the downstream side surface 19a and the upstream side surface 19b are exposed and the foundation is destabilized. FIG. 2C is an elevation view of the pier 1c in which the ground 3 is excavated so that the downstream side surface 19b is exposed and the foundation is destabilized.

  Each figure in the lower part of FIG. 2 is a locus for a predetermined time with the vertical speed of the upstream sensor 7b as the horizontal axis and the vertical speed of the downstream sensor 7a as the vertical axis. The trajectory 21a shown in FIG. 2D is that of the pier 1a shown in FIG. In a bridge pier 1a with a sufficiently sound foundation as shown in FIG. 2A, vibration as shown by an arrow B occurs due to the constant fine movement of the ground 3 and the flow of water 5 (FIG. 1). At this time, the top end of the bridge pier 1a vibrates substantially in the vertical direction at the same time, and as shown in FIG.

  The trajectory 21b shown in FIG. 2 (e) is that of the pier 1b shown in FIG. 2 (b). As shown in Fig. 2 (b), on the pier 1b where the upstream and downstream sides have been scoured and the foundation is destabilized, the ground 3 is constantly finely moved and the water 5 (Fig. 1) Vibration as shown by arrow C occurs. At this time, the rocking vibration is dominant, and as shown in FIG. 2 (e), a locus 21b centered on 45 degrees to the left is drawn.

  A trajectory 21c shown in FIG. 2 (f) is that of the pier 1c shown in FIG. 2 (c). In the pier 1c in which only the upstream side is scoured and the foundation is destabilized as shown in FIG. 2 (c), it is indicated by an arrow D due to the fine movement of the ground 3 and the flow of water 5 (FIG. 1). Such vibration occurs. At this time, as shown in FIG. 2F, a locus 21c substantially parallel to the horizontal axis is drawn.

  From the experimental results shown in FIG. 2, it was confirmed that the shape of the trajectory of the vertical speed varies depending on the state of the foundation of the pier 1.

  FIG. 3 shows the trajectory of the vertical velocity obtained by installing the soundness evaluation device on the three piers of the bridge in service. Each figure shown in FIG. 3 shows a trajectory drawn with the vertical speed of the upstream sensor 7b (FIG. 1) as the horizontal axis and the vertical speed of the downstream sensor 7a (FIG. 1) as the vertical axis.

  The trajectory 23a shown in FIG. 3 (a) is evaluated to be a sound pier that is not scoured and is centered on 45 degrees upward as in the trajectory 21a shown in FIG. 2 (d). . The locus 23b shown in FIG. 3 (b) is centered on 45 degrees to the left as in the locus 21b shown in FIG. 2 (e), and both the upstream side and the downstream side are scoured and unstable. It is evaluated as a pier that has become a pier. The trajectory 23c shown in FIG. 3C is substantially parallel to the horizontal axis like the trajectory 21c shown in FIG. 2F, and the pier that has been destabilized by scouring only the upstream side. It is evaluated.

  The soundness of the pier depicting the trajectory 23a shown in FIG. 3 (a) is high, and the health of the pier depicting the trajectory 23b shown in FIG. 3 (b) and the trajectory 23c shown in FIG. 3 (c). The evaluation result that is low coincides with the result of evaluation using the soundness determination method (3) described above.

  Thus, in this Embodiment, the soundness evaluation apparatus as shown in FIG. 1 is installed in the pier 1, the trajectory of a vertical direction speed is drawn, and the soundness of the foundation of the pier 1 is judged from the shape. By constantly monitoring using such a soundness evaluation device, the state of the pier can be easily evaluated even when the amount of water increases. The soundness evaluation device may be provided with an alarm function for generating a sound in addition to the display device corresponding to the determination result. Thereby, the change of the state of a pier can be detected more rapidly.

  As mentioned above, although preferred embodiment of the soundness evaluation method of the block-shaped structure concerning this invention and the soundness evaluation apparatus of a block-shaped structure concerning this invention was described, this invention is not limited to this example. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, in FIG. 2 and FIG. 3, the trajectory of the vertical speed is illustrated for determining the soundness level, but in addition to the vertical speed, the trajectory of the vertical acceleration and the virtual displacement calculated from the vertical speed is illustrated. You may judge the soundness. The configuration of the soundness evaluation apparatus is not limited to that shown in FIG. A device such as a computer that installs the sensor 7 and the measuring device on the pier 1 and performs trajectory illustration and soundness determination may be disposed in another location. The soundness evaluation device and the evaluation method can also be applied to block-like structures other than bridge piers.

Elevation view of pier 1 with soundness evaluation device Results of comparative experiments on vibration properties for piers actually installed in rivers Vertical velocity trajectory obtained by installing a soundness evaluation device on three piers of a bridge in service

Explanation of symbols

1 ......... Bridge pier 3 ......... Ground 7,7a, 7b ......... Sensor 17 ......... Computers 21a, 21b, 21c ......... Track 23a, 23b, 23c ......... Track

Claims (6)

Using the sensors installed at two locations near the upper end of the block-like structure, obtaining the behavior data of the block-like structure (a);
Step (b) illustrating the trajectory of a specific vertical component based on the behavior data;
A step (c) of evaluating the soundness of the foundation of the block-shaped structure from the shape of the trajectory;
A method for evaluating the degree of soundness of a block-like structure, comprising:   The soundness evaluation method for a block-shaped structure according to claim 1, wherein the specific vertical component is any one of a vertical velocity, a vertical acceleration, and a vertical displacement.   The soundness evaluation method for a block-shaped structure according to claim 1, wherein the sensor is provided at a position facing an upper end surface of the block-shaped structure. Sensors installed at two locations near the upper end of the block-shaped structure and acquiring behavior data of the block-shaped structure;
Means for illustrating a trajectory of a specific vertical component based on the behavior data;
Means for evaluating the foundation soundness of the block-like structure from the shape of the trajectory;
A block-structure soundness evaluation apparatus comprising:   The soundness evaluation apparatus for a block-shaped structure according to claim 4, wherein the specific vertical component is a vertical velocity.   The soundness evaluation apparatus for a block-shaped structure according to claim 4, wherein the sensor is provided at a position facing an upper end surface of the block-shaped structure.

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