JP5369027B2 - Safety evaluation method for earth retaining structures - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety evaluation method of an earth retaining structure, by which a simple and prompt inspection of the earth retaining structure can be performed. <P>SOLUTION: The safety evaluation method of the earth retaining structure which is constructed by a reinforced earth construction method with a concrete panel and a panel anchor. The method comprises at least: a step for setting a concrete sensor for detecting strain in the concrete panel; a step for setting a soil pressure sensor for detecting a soil pressure upon the panel anchor connected to the concrete panel; a step for setting on the concrete panel an RFID tag which collects information from the concrete sensor, and soil pressure sensor and outputs data by an RFID (Radio Frequency Identification) method; and a step for obtaining a measured value from the RFID tag by the RFID method. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a safety evaluation method for a soil retaining structure constructed by a reinforced earth method using a concrete panel and a panel anchor.

  Conventionally, a reinforced earth construction method is known in which soil is piled up and concrete panels are sequentially piled up to construct a retaining structure while preventing soil near the surface from spilling. The retaining structure constructed by such a reinforced earth method is considered to have no significant change in strain or load under normal use conditions. However, after natural disasters such as earthquakes and torrential rains, it is expected that the ground will deform and the strain and load values of the retaining structure will change greatly.

  Also, during operation, there is a risk that a load is generated on the concrete panel and the panel anchor due to an overload of an automobile or a building, frost heaving in which expansion pressure is generated due to freezing of the soil behind the concrete panel, and crustal movement.

  Therefore, by periodically measuring the strain of concrete panels and panel anchors due to these external factors, it is possible to take measures such as refurbishment before the reinforced soil is severely damaged, which is effective for preventive maintenance. It is believed that there is.

JP 2009-281104 A JP 2003-336261 A

  However, conventionally, when carrying out daily inspections, since cracks and steps between concrete panels were visually observed, a size that can be discerned visually, for example, a width of 0.2 mm to 1 mm Only the above cracks could be detected, and cracks below that could not be detected. Moreover, when carrying out an emergency check, it was time-consuming and time-consuming because it was confirmed whether there was any outflow of soil from the joints or whether the entire wall surface was deformed.

  Also, with regard to grasping the usage limit state, the conventional technology can grasp only changes that can be visually confirmed, so quantitative data cannot be obtained, and inspection records are efficiently used for maintenance management. I couldn't. Here, in the method of attaching a wired strain gauge, since the cable is exposed from the concrete panel, the appearance of the structure is extremely impaired. Furthermore, since cables deteriorate over time, measurement over a long period of time is difficult.

  In addition, the recording method of the measurement result is generally output to a medium such as paper. For example, RC structures such as bridges are regularly inspected every five years. Meanwhile, the inspection records may be lost due to changes in the person in charge.

  Further, regarding the rapidity of emergency inspection, visual detection requires time and it is not easy to appropriately evaluate the risk of the structure.

  This invention is made | formed in view of the above situations, and it aims at providing the safety evaluation method of a retaining structure which can check a retaining structure easily and rapidly.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the safety evaluation method for a retaining structure according to the present invention is a safety evaluation method for a retaining structure constructed by a reinforced soil construction method using a concrete panel and a panel anchor, and detects strain in the concrete panel. A step of installing a concrete sensor, a step of installing an earth pressure sensor for detecting earth pressure on a panel anchor connected to the concrete panel, collecting information on the concrete sensor and the earth pressure sensor, and collecting RFID (Radio Frequency Identification) ) Method for installing the RFID tag for outputting data on the concrete panel, and at least a step for obtaining a measurement value from the RFID tag by the RFID method.

  As described above, since the measurement value is acquired from the RFID tag by the RFID method, work such as connection is not required at the time of measurement, work efficiency is improved, and the aesthetic appearance of the concrete panel can be maintained. Furthermore, measurements can be performed over a long period of time.

  (2) Moreover, in the safety evaluation method of the earth retaining structure of the present invention, the RFID tag can communicate with a plurality of channels, and the step of electrically connecting the concrete sensor and the RFID tag; A step of electrically connecting the earth pressure sensor and the RFID tag, and collecting information on the concrete sensor and the earth pressure sensor by an RFID method using different channels. .

  In this way, the RFID tag can communicate with a plurality of channels, electrically connect the concrete sensor and the RFID tag, electrically connect the earth pressure sensor and the RFID tag, and use different channels. Since the information of the concrete sensor and earth pressure sensor is collected by the RFID method, interference between channels can be prevented and information of both the concrete sensor and earth pressure sensor can be obtained in one measurement operation. It becomes possible to collect. This makes it possible to improve the efficiency of measurement work. Also, in the concrete panel installation work, it is only necessary to perform cable connection and waterproof treatment without carrying out mortar burying work, so that the work efficiency can be improved.

  (3) Moreover, the safety evaluation method of the earth retaining structure of the present invention includes a step of previously providing an embedded space for the RFID tag in the concrete panel, and a step of connecting the concrete sensor or the earth pressure sensor to the RFID tag. And a step of embedding the RFID tag in the embedding space after completion of the concrete panel.

  In this way, an embedded space for the RFID tag is provided in advance in the concrete panel, and the concrete sensor or earth pressure sensor is connected to the RFID tag. After the concrete panel is completed, the RFID tag is embedded in the embedded space. When connecting a panel anchor provided with a pressure sensor, an RFID tag connected in advance to the earth pressure sensor via a cable can be installed in the embedded space, and the RFID tag can be embedded using a non-shrink mortar or the like. . This eliminates the need for on-site connection work and prevents problems such as signal attenuation due to incomplete connection.

  (3) Moreover, the safety evaluation method of the earth retaining structure of the present invention includes a step of installing the concrete sensor on a concrete panel having a height at which the earth pressure is maximized, and a concrete having a height at which the earth pressure is maximized. And a step of installing the earth pressure sensor on a panel anchor connected to the panel.

  In this way, the concrete sensor is installed on the concrete panel with the highest earth pressure, and the earth pressure sensor is installed on the panel anchor connected to the concrete panel with the highest earth pressure. You can grasp the safety of concrete panels well.

  (4) Further, in the safety evaluation method for a retaining structure according to the present invention, any two adjacent concrete sensors may be installed apart by a maximum distance at which stress generated in the concrete panel is transmitted. Features.

  In this way, any two adjacent concrete sensors are installed apart from each other by the maximum distance at which the stress generated in the concrete panel is transmitted, so that the concrete sensors are installed on all concrete panels. This contributes to cost reduction and secures detection accuracy.

  (5) Moreover, in the safety evaluation method of the earth retaining structure of this invention, the said concrete sensor is installed in the connection part vicinity of the said concrete panel and the said panel anchor, It is characterized by the above-mentioned.

  In this way, the concrete sensor is installed in the vicinity of the connecting portion between the concrete panel and the panel anchor, so that the safety of the concrete panel can be grasped efficiently. That is, since the tensile stress generated in the concrete panel concentrates on the connecting portion of the panel anchor, it is possible to improve the detection efficiency by installing a concrete sensor in the vicinity thereof.

  According to the present invention, when measuring strain data, the measurement value is acquired from the RFID tag by the RFID method, so that work such as connection is not required, work efficiency is improved, and the aesthetic appearance of the concrete panel can be maintained. it can.

It is a figure which shows the concept of this embodiment. It is a figure which shows the earth pressure distribution in the earth retaining structure which consists of clay ground. It is a figure which shows an example of the attachment position of a concrete sensor. It is a figure which shows an example of the plane and cross section which show a mode that the concrete panel was connected. (A) It is a top view which shows the stress distribution in a concrete panel. (B) It is sectional drawing which shows the stress distribution in a concrete panel. It is a figure which shows the installation method of the RFID tag. It is a figure which shows the installation method of the RFID tag. It is a figure which shows the installation method of the RFID tag. It is a flowchart which shows the safety evaluation method of a earth retaining structure.

  Next, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating the concept of the present embodiment. The earth retaining structure 1 is constructed by a reinforced earth method. That is, the soil 10 is raised, and the concrete panel 3 prevents the soil near the surface from spilling down, and the panel anchor 2 is connected to the concrete panel 3 and these are sequentially stacked. A concrete sensor SP is provided inside the concrete panel 3. The panel anchor 2 is provided with an earth pressure sensor SD. Information detected by the concrete sensor SP and the earth pressure sensor SD is collected in the RFID tag 5. The earth retaining structure 1 is subjected to an upper load such as an automobile or a building. As a result, the main earth pressure P is applied to the concrete panel 3. Due to such external factors, preventive maintenance is achieved by periodically measuring the strain in the concrete panel 3 and the panel anchor 2.

  FIG. 2 is an example showing the earth pressure distribution in the earth retaining structure made of clay ground. The earth pressure applied to the concrete panel 3 varies greatly depending on the geology (sand, clay, etc.), soil constants (adhesive strength c, shear resistance angle φ, density γ), and overlay load (residential land, vehicle, embankment, etc.). For this reason, when designing a retaining structure (such as a vertical embankment wall), the panel thickness, the number of reinforcing bars, and the type and length of the anchor are determined in consideration of these conditions. In the earth pressure distribution shown in FIG. 2, the magnitude of the earth pressure and the height indicating the maximum earth pressure differ depending on the state of the embankment. The concrete panel 3 disposed at a position where the earth pressure is large has design requirements such as increasing the thickness, thickening the anchor, and using a high strength product as the anchor steel type. Then, referring to these, the mounting position of the concrete sensor is selected.

  FIG. 3 is a diagram illustrating an example of an attachment position of the concrete sensor. If a concrete sensor is attached to every concrete panel, a lot of data can be obtained. However, on the other hand, the measurement takes time and the cost increases. For this reason, it is not easy to perform efficient maintenance. In order to efficiently grasp the safety of the wall surface, as described above, it is preferable to measure around the height at which the earth pressure becomes the largest.

  Furthermore, the stability of the entire wall surface can be grasped by performing measurements in the vertical and horizontal directions at an appropriate interval. Here, an appropriate interval means a limit distance at which the stress of the concrete panels on both sides to be measured is transmitted.

  FIG. 4 is a plan view and a cross-sectional view showing a state in which concrete panels are connected. As shown in FIG. 4, when the connecting surface of the concrete panel is uneven, stress is transmitted to adjacent concrete panels, and the stress transmission is gradually attenuated. For example, the upper limit of the horizontal interval is about 4 rows. However, in actuality, since the mounted load is rarely uniform, it is necessary to determine the measurement position in consideration of on-site conditions.

  FIG. 5A is a plan view showing the stress distribution in the concrete panel. FIG. 5B is a cross-sectional view showing the stress distribution in the concrete panel. The tensile stress in the concrete panel is concentrated on the joint portions 2a and 3a. Therefore, a concrete sensor is installed in the vicinity of the joint portions 2a and 3a. Thereby, the safety | security of a concrete panel can be grasped | ascertained efficiently.

  Next, an installation method of the RFID tag 5 connected to the concrete sensor SP and the earth pressure sensor SD will be described. 6 to 8 are diagrams showing a method of installing the RFID tag 5. As shown in FIG. 6, the RFID tag 5 to be connected to the concrete sensor SP is fixed in place at the time of manufacturing the concrete panel 3 in advance by tightening to a reinforcing bar, an insert or the like or using a spacer. Is embedded at a predetermined position in the concrete panel 3. The RFID tag 5 is preferably installed at a position closer to the front side of the concrete panel 3 than the reinforcing bar, or at a portion where the reinforcing bar in the concrete panel 3 is not arranged. This is because the antenna in the RFID tag 5 is not affected by the reinforcing bars.

  The installation method of the RFID tag 5 connected to the earth pressure sensor SD can be selected from the following two methods. That is, (1) as shown in FIG. 7, an embedded space is provided in a predetermined position in the concrete panel 3 in an open state on the back side of the concrete panel 3, and the earth pressure sensor SD is provided on the concrete panel 3. When the panel anchor 2 is connected, the RFID tag 5 connected to the earth pressure sensor SD via a cable is placed in the buried space and buried using a non-shrink mortar, etc. (2) in FIG. As shown, a sensor connection cable terminal extended from the RFID tag 5 embedded at a predetermined position in the concrete panel 3 is provided from the back side of the concrete panel 3, and the earth pressure sensor SD is provided on the concrete panel 3. When connecting the panel anchor 2, the cable terminal for the RFID tag connection extended from the earth pressure sensor SD and the sensor connection A terminal of the cable is a method of applying a waterproofing treatment by connecting.

  By the method of (1), the embedded space can be easily formed by installing a highly elastic material such as polystyrene foam or rubber before placing the concrete and removing it after manufacturing the concrete panel 3. it can. In the method (1), the concrete sensor SP and the earth pressure sensor SD are respectively connected to different RFID tags 5. Therefore, it is preferable that each RFID tag 5 is installed at a position away from the concrete panel 3 in order to prevent interference between the antennas.

  In the method (2), the concrete sensor SP and the earth pressure sensor SD can be connected to the common RFID tag 5 by using the RFID tag 5 of a plurality of channels. According to this method, the interference of the antenna can be prevented, and at the same time, the data of both sensors can be read in one measurement operation, so that the measurement operation can be made more efficient. Also in the panel installation work, only the cable connection and waterproofing are performed, which is preferable in terms of efficiency compared to the method (1) that requires the mortar burying work. On the other hand, the method (1) is excellent in that it does not involve connection work, and therefore does not cause problems such as signal attenuation due to incomplete connection.

  Next, a safety evaluation method for earth retaining structures constructed as described above. This will be described with reference to the flowchart shown in FIG. A earth retaining structure, for example, a vertical embankment wall is completed (step S1), and a completion inspection is performed (step S2). Here, the initial value of the strain of the concrete panel and the axial force of the panel anchor is measured. Next, it is determined whether the strain and axial force are less than the design load (step S3). If they are not less than the design value, cause investigation and countermeasure work are performed (step S4), and the process proceeds to step S2. On the other hand, when it is below the design value in step S3, it is in service (step S5).

  Next, when a natural disaster such as an earthquake or heavy rain occurs (step S6), an emergency inspection is performed (step S7). Here, the strain information of the concrete panel and the axial force information of the earth pressure sensor are measured. And it is judged whether it is below an allowable value (Step S8), and when it is below an allowable value, it changes to Step S14. On the other hand, if it is not less than the allowable value in step S8, traffic regulation and use restriction are performed (step S9), cause investigation and countermeasure work are performed (step S10), and the strain of the concrete panel and the axial force of the earth pressure sensor are again obtained. Is measured (step S11), and the process proceeds to step S14.

  On the other hand, in service in step S5, periodic inspection and daily management are performed (step S12), and the strain of the concrete panel and the axial force of the earth pressure sensor are measured (step S13). And it is judged whether it is below an allowable value (Step S14), and when not below an allowable value, it changes to Step S10. On the other hand, if it is equal to or less than the allowable value, a subsequent maintenance plan is formulated (step S15), data is recorded in the RFID tag (step S16), and the process proceeds to step S5. In step S15, investigations such as increase / decrease in inspection frequency and investigation of other deterioration factors are performed.

  As described above, according to the present embodiment, a concrete sensor for detecting strain is installed on a concrete panel having a height at which the calculated earth pressure is maximized, and the concrete having a height at which the calculated earth pressure is maximized. Since the earth pressure sensor that detects earth pressure is installed on the panel anchor connected to the panel, the safety of the concrete panel can be grasped efficiently. In addition, since the measurement value is acquired from the RFID tag by the RFID method, work such as connection for measurement is not required, work efficiency is improved, and the aesthetic appearance of the concrete panel can be maintained.

DESCRIPTION OF SYMBOLS 1 Earth retaining structure 2 Panel anchor 2a, 3a Joint part 3 Concrete panel 5 RFID tag

Claims (6)

A method for evaluating the safety of a retaining structure constructed by a reinforced earth method using concrete panels and panel anchors,
Installing a concrete sensor for detecting strain on the concrete panel;
Installing an earth pressure sensor for detecting earth pressure on a panel anchor connected to the concrete panel;
Collecting information of the concrete sensor and the earth pressure sensor, and installing an RFID tag on the concrete panel that outputs data by an RFID (Radio Frequency Identification) method;
A method for evaluating the safety of a soil retaining structure, comprising at least a step of acquiring a measurement value from the RFID tag by an RFID method. The RFID tag can communicate with a plurality of channels,
Electrically connecting the concrete sensor and the RFID tag;
A step of electrically connecting the earth pressure sensor and the RFID tag, and collecting information on the concrete sensor and the earth pressure sensor in an RFID system using different channels. The method for evaluating the safety of a retaining structure according to claim 1. A step of previously providing an embedded space for the RFID tag in the concrete panel;
Connecting the concrete sensor or the earth pressure sensor to the RFID tag;
The method for evaluating safety of a earth retaining structure according to claim 1, further comprising a step of embedding the RFID tag in the embedding space after the concrete panel is completed. A step of installing the concrete sensor on a concrete panel having a height at which earth pressure is maximized;
The earth retaining device according to any one of claims 1 to 3, further comprising a step of installing the earth pressure sensor on a panel anchor connected to a concrete panel having a height at which the earth pressure is maximized. Safety evaluation method for structures.   The earth retaining structure according to any one of claims 1 to 4, wherein any two of the adjacent concrete sensors are disposed apart by a maximum distance at which stress generated in the concrete panel is transmitted. Safety evaluation method for things. The said concrete sensor is installed in the connection part vicinity of the said concrete panel and the said panel anchor, The safety evaluation method of the earth retaining structure in any one of Claims 1-5 characterized by the above-mentioned.

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