JP2006162511A - System for detecting ground anchor tensile force - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for detecting ground anchor tensile force which can reduce the cost and labor required for tensile force detection of tightly-drawn wire. <P>SOLUTION: An anchor plate 33 which receives the tensile force of the tense wire 23 is provided with a strain sensor 41 for detecting the amount of bending strain of the anchor plate 33. A tensile force monitoring device is provided, which is electrically connected to the strain sensor 41 and calculates the decrease in the tensile force of the tense wire 23 from the amount of bending strain detected by the strain sensor 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ground anchor tension detection system for monitoring tension force acting on a tension wire of a ground anchor used for imparting tension force in prestressed concrete, retaining earth on slopes, and the like.

FIG. 19 shows a general structure of a ground anchor used for applying tension in prestressed concrete, retaining earth on an inclined ground, or the like.
In the illustrated ground anchor 10, reference numeral 1 is a concrete member created on the ground slope, and reference numeral 2 is an anchor plate 2 installed on the surface of the concrete member 1. The concrete member 1 and the anchor plate 2 are formed with through holes formed substantially coaxially, and a tension wire 6 housed in a resin sheath 4 is inserted through the through holes.

Although not shown in FIG. 19, the proximal end of the tension wire 6 is fixed to an anchor body embedded in a stable ground below the concrete member 1. In addition, an anchor head 8 is fixed to a distal end portion of the tension wire 6 led out from the insertion hole of the concrete member 1 and the anchor plate 2 to the ground side.
The anchor head 8 is fixed to the tensioned wire 6 that has been tensioned by pulling the tip of the tensioned wire 6 with a jack or the like, and is pressed and fixed to the anchor plate 2 by the tension that acts via the tensioned wire 6. Has been.
Reference numeral 9 in FIG. 19 denotes an oil cap 9 that is fitted and attached to the distal end portion of the tension wire 6 to which the anchor head 8 is attached, and serves to prevent corrosion of the installed tension wire 6.

In such a ground anchor 10, the tension force applied to the tension wire 6 is loosened due to secular change, which may reduce the initial support strength of the tension wire 6. Therefore, it is necessary to periodically check the tension of the tension wire 6.
Conventionally, the following two methods are known as the ground anchor tension detection method for detecting the tension of the tension wire 6 in the installed ground anchor 10.
One is to remove the oil cap 9 at the time of inspection and connect the tension jack used when installing the ground anchor 10 to the tip of the exposed tension wire 6, and measure the remaining tension with the tension jack. It is a method to do.
The other is the method shown in FIG. This is because a hydraulic or electric load cell 12 is incorporated between the anchor plate 2 and the anchor head 8 in the ground anchor 10 described above, and at the time of inspection, a measurement circuit is connected to the load cell 12 and the load cell 12 is supplied at a specified pressure. The tension | tensile_strength fall of the tension | tensile_strength wire 6 is detected by the output value of the load cell 12 when operating (for example, refer patent document 1).

JP 2002-257654 A

  However, in the case of the ground anchor tension detection method using a tension jack, the tension jack is a heavy machine, and there is a problem that it takes a lot of labor to bring it into the field at the time of inspection.

On the other hand, in the case of the ground anchor tension detection method using the hydraulic or electric load cell 12, the hydraulic or electric load cell 12 itself is expensive, and further, the output signal from the load cell 12 is measured at the time of inspection. Therefore, an expensive measurement circuit is required, so that the cost required for detecting the tension of the tension wire 6 becomes high.
In order to assemble the hydraulic or electric load cell 12, a gap corresponding to the height dimension h of the load cell 12 must be secured between the anchor plate 2 and the anchor head 8. This height dimension h Therefore, it is difficult to form a gap for adding the load cell 12 to the existing ground anchor 10 later, and there is a problem that it cannot be used other than the ground anchor in which the load cell 12 is installed in advance.

  Even if the gap can be secured, the existing ground anchor 10 has a short extra length at the tip of the tension wire 6, so that the tension wire 6 is pulled by a tension jack or the like to form the gap. It was difficult.

  The present invention aims to solve the above-mentioned problems, can reduce the cost and labor required for tension detection of the tension wire in the ground anchor, and can be used for an existing ground anchor that has not been dealt with in advance. Another object of the present invention is to provide a ground anchor tension detection system capable of detecting tension.

The above object is achieved by the following configuration.
(1) An anchor plate that receives a tension force of a tension wire is equipped with a strain sensor, and a tension state of the tension wire is detected from a bending strain amount of the anchor plate detected by the strain sensor. Tension detection system.

(2) In (1) above, the amount of bending strain output from the strain sensor can be displayed and stored in a storage medium while being electrically connected to and disconnected from the strain sensor of the anchor plate. A ground anchor tension detecting system comprising a tension monitoring device for memorizing.

(3) The ground anchor tension detection system according to (2), wherein the storage medium is mounted on the anchor plate.

(4) In the above (2) or (3), the bending strain amount stored in advance in the storage medium is compared with the bending strain amount detected by the strain sensor, and the tension force in the tension wire is reduced. A ground anchor tension detection system characterized by detecting presence or absence.

(5) In the above (3) or (4), the strain sensor and the storage medium provided in the anchor plate and the tension monitoring device are connected by wireless communication. Tension detection system.

(6) In any one of the above (1) to (5), a spacer that floats the pressure-receiving area on the anchor plate on which the tension of the tension wire acts from a concrete member formed on the ground slope or the like. A ground anchor tension detection system characterized by comprising.

(7) In any one of the above (1) to (6), at least the anchor head locked by the tension wire is placed on the anchor head in order to float from the concrete member formed on the ground slope or the like. A ram chair to be covered, and an attachment arranged in the ram chair and capable of gripping the anchor head are attached, and the anchor head coupled to the ram chair and gripped by the attachment by hydraulic pressure is lifted by a reaction force of the ram chair A ground anchor tension detection system characterized by enabling the use of hall jacks.

In the ground anchor tension detection system described in the above (1), the sensor equipped for measuring the tension of the tension wire is compared with a conventional large-sized hydraulic or electric load cell or a heavy jack. It is a small, lightweight and inexpensive strain sensor. Further, the strain sensor output signal is a weak electrical signal, and the tension monitoring device that processes the output signal is also compared with a measurement circuit that operates a hydraulic or electrical load cell, for example, a portable personal computer (notebook). Small, lightweight and inexpensive equipment using a personal computer) is sufficient.
Therefore, it is possible to reduce the cost and labor required for detecting the tension of the tension wire in the ground anchor.
In addition, since the anchor plate of the present invention has a smaller thickness (height) than a hydraulic or electric load cell, the anchor head is pulled by a tension jack or the like, and the anchor head is pulled. By slightly floating from the anchor plate, replacement with the existing anchor plate can be performed relatively easily.
Therefore, it is possible to detect the tension of the tension wire even with respect to the existing ground anchor, and the versatility is high.

  In the ground anchor tension detection system described in (2) above, the tension monitor is not stationary with respect to the strain sensor mounted on the anchor plate, but only when necessary (when measuring tension). Since a single tension monitoring device can be shared by many ground anchors and the number of tension monitoring devices can be reduced, the tension force can be reduced. Equipment costs necessary for detection can be greatly saved.

  In the ground anchor tension detection system described in (3) above, the reference tension initially set for the tension wire and the amount of bending strain of the anchor plate detected by the strain sensor at that time are stored in the storage medium equipped on the anchor plate. As described in (4) above, the amount of bending strain detected by the strain sensor at the time of inspection is compared with the initial amount of bending strain of the storage medium. The presence or absence of can be easily detected.

  In the ground anchor tension detection system described in (5) above, the electrical connection between the storage medium and the strain sensor equipped on the anchor plate and the tension monitor is made wireless by RFID (Radio Frequency Identification) or the like. By doing so, it is possible to eliminate the trouble of connecting the tension monitoring device to the anchor plate when checking the tension, etc., so that the tension checking operation can be performed quickly and smoothly.

  In the ground anchor tension detection system described in (6) above, the tension of the tension wire acting on the anchor plate even when the diameters of the insertion holes of the anchor plate and the concrete member with which the anchor plate abuts are the same. With the force, the anchor plate surely generates a bending strain, and the presence or absence of a decrease in the tension force in the tension wire can be reliably detected.

  In the ground anchor tension detection system according to the above (7), since the center hole jack that holds and lifts the anchor head locked by the tension wire can be applied, the tip of the tension wire in the existing ground anchor Even if the surplus length is short, the anchor head gripped by the attachment is lifted to form a gap between the anchor plate and the concrete member, so that the anchor plate of the present invention can be inserted.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a ground anchor tension detection system according to the present invention will be described in detail with reference to the drawings.

  1 to 5 show an embodiment of a ground anchor tension detecting system according to the present invention. FIG. 1 is a longitudinal sectional view of a ground anchor applied to the ground anchor tension detecting system according to the present invention. 2 is a block diagram of the ground anchor tension detection system shown in FIG. 1, FIG. 3 is a bottom view of the anchor plate shown in FIG. 1, FIG. 4 is a side view of the anchor plate shown in FIG. It is explanatory drawing of the form which connected the tension force monitoring apparatus to the anchor plate shown in FIG.

  The ground anchor tension detection system 100 according to this embodiment monitors the tension acting on the tension wire 23 of the ground anchor 21 used for tension application in prestressed concrete, earth retaining on an inclined ground, or the like.

  The ground anchor 21 includes an anchor body 27 embedded in a stable ground 25 in the ground, a concrete member 31 formed on a surface slope 29 above the ground 25, and an anchor plate installed on the surface of the concrete member 31. 33, a tension wire 23 having a proximal end fixed to the anchor body 27 and a distal end inserted through insertion holes 31a and 33a formed through the concrete member 31 and the anchor plate 33 and led out to the ground side, and a tension jack An anchor head 35 that is fixed to the distal end side of the tension wire 23 that has been tensioned by pulling or the like and that is pressed and fixed to the anchor plate 33 by a tension force applied to the tension wire 23, and a tension wire that is fixed to the anchor head 35 23, and an oil cap 36 fitted and attached to the tip end portion.

The anchor body 27 is formed into a predetermined size and shape by injecting a cement grout material. The tension wire 23 is laid in a form inserted through a resin sheath 37 having predetermined elastic characteristics.
The tension wire 23 and the anchor head 35 are fixed by driving a tapered tubular wedge 39 into a wire insertion hole formed in the anchor head 35 in order to insert the tension wire 23.

  As shown in FIGS. 1 and 2, the ground anchor tension detecting system 100 according to the present embodiment includes an anchor plate 33 on which a strain sensor 41 and a storage medium 43 described later are fixedly mounted, and the strain sensor 41 and the storage. The medium 43 is composed of a tension monitoring device 45 that can be electrically connected and disconnected freely via a connector 44 provided on the anchor plate 33.

The strain sensor 41 is embedded in an anchor plate 33 formed of a rust-proof steel plate, converts a bending strain generated in the anchor plate 33 into an electrical signal, and outputs the electrical signal. As shown in FIGS. The sensor mounting recess 47 formed on the back surface of the anchor plate 33 is fixedly installed. A commercially available strain gauge can be used for the strain sensor 41.
The anchor plate 33 has a first strain sensor 41a for measuring the amount of bending strain of the anchor plate 33 as a strain sensor 41, and a second for correcting the measured value with respect to fluctuations in the outside air temperature. And a strain sensor (temperature correction sensor) 41b.

The storage medium 43 is a storage element that can rewrite data, and for example, E ² PROM or the like is used. This storage medium 43 is also attached and fixed to a recess 49 for mounting a storage element formed on the back surface of the anchor plate 33.

  The first and second strain sensors 41a and 41b, the storage medium 43, and the like described above need to be provided with high weather resistance (waterproofness) in order to prevent contamination due to outside air or moisture. In the case of the embodiment, as shown in FIG. 4, after mounting these sensors or the like in the recesses 47 and 49, potting is filled with waterproof resin around the recesses 47, 49, and A waterproofing treatment 51 such as a waterproof lid covering the opening is provided.

The connection connector 44 is a waterproof connector attached to the surface side of the anchor plate 33, and is connected to a connection cable 46 of the tension monitoring device 45 as shown in FIG.
The connection connector 44 and the strain sensor 41 or the connection connector 44 and the storage medium 43 are connected by a communication cable 53 inserted through a cable passage formed in the anchor plate 33.

  As shown in FIG. 2, the tension monitor device 45 includes a strain sensor operating circuit 61 having a balanced circuit that reads the output signal of the strain sensor 41 and an amplifier circuit that amplifies the received signal, and the strain sensor operating circuit 61. An analog signal to be output is converted into a digital signal, and an A / D conversion circuit 62 that outputs the digital signal. A bending strain amount of the anchor plate 33 is calculated from an output signal of the A / D conversion circuit 62, and data reading / An arithmetic processing circuit (MPU) 63 for performing a writing process, a display circuit 65 having a liquid crystal display for displaying data calculated by the arithmetic processing circuit 63 on a screen, and a keyboard for setting processing contents by the arithmetic processing circuit 63 A storage medium 68 for storing input data from the input operation circuit 66 and processing data by the arithmetic processing circuit 63; It is configured to include.

In the case of the present embodiment, it is assumed that a CF (compact flash) memory, which is a commercially available memory card, is used as the storage medium 68, but it may be changed to a form using other memory.
For example, a commercially available notebook computer or a smaller mobile computer can be used as the tension monitor 45.

When the ground anchor 21 is installed, the tension monitor device 45 is connected to the connection connector 44, and when the reference tension is applied to the tension wire 23 as shown in FIG. The measured value is stored in the storage medium 43 as the initial set voltage. The voltage stored in the storage medium 43 is not limited to that corresponding to the reference tension.
As shown in FIG. 7, the tension sensor 1, 2, and 3 in the middle of reaching the reference set tension force measures the output value of the strain sensor 41 and stores it in the storage medium 43. The correlation between the tension applied to the wire 23 and the bending strain generated in the anchor plate 33 can be recorded and used as reference data for subsequent inspection.

  When the tension monitoring device 45 of the present embodiment is connected to the connector for connection 44 at the time of inspection, the anchor plate 33 stored in the storage medium 43 in advance when the ground anchor 21 is installed as shown in FIG. The amount of bending strain is read, the amount of bending strain read is compared with the amount of bending strain detected by the strain sensor 41 at the time of inspection, and the presence or absence of a decrease in tension in the tension wire 23 is detected from the difference in the amount of each strain. (judge.

In the ground anchor tension detection system 100 according to the embodiment described above, a sensor provided on the ground anchor 21 side for measuring the tension of the tension wire 23 is a conventional large hydraulic or electric load cell, The strain sensor 41 is smaller and lighter and cheaper than a tension jack that is a heavy machine. Further, the output signal of the strain sensor 41 is a weak electric signal, and the tension monitoring device 45 that processes the output signal is also compared with a measurement circuit that operates a hydraulic or electric load cell, for example, a portable personal computer. A small, lightweight and inexpensive facility using a (notebook personal computer) or the like is sufficient.
Therefore, it is possible to reduce the cost and labor required for detecting the tension of the tension wire 23 in the ground anchor 21.

Further, when it is necessary to measure the tension with an existing ground anchor that has not been dealt with in advance (for example, the ground anchor 10 shown in FIG. 19), the anchor plate of the existing ground anchor is used as the anchor plate according to the present invention. It may be replaced with 33.
The anchor plate 33 according to the present invention has a small thickness (height) as compared with a hydraulic or electric load cell. Therefore, the anchor head 8 is slightly pulled by pulling the tip of the tension wire 6 with a tension jack or the like. In this state, it is relatively easy to replace the existing anchor plate with the anchor plate 33 according to the present invention.
Accordingly, the tension force of the tension wire 6 can be detected even for the existing ground anchor shown in FIG. 19, and the versatility is high.

  Further, in the ground anchor tension detection system 100 shown in the above embodiment, the tension monitor 45 is not stationary with respect to the strain sensor 41 mounted on the anchor plate 33 (when measuring tension). A single tension monitoring device 45 can be shared by a number of ground anchors 21, and the tension monitoring device 45 can be shared by a number of ground anchors 21. Since the number of equipment can be reduced, the equipment cost necessary for tension detection can be greatly saved.

  Further, in the ground anchor tension detection system 100 shown in the above embodiment, the reference tension set initially on the tension wire 23 and the strain sensor at that time are stored in the storage medium 43 mounted on the anchor plate 33 as described above. 41 is stored, and the strain amount detected from the strain sensor 41 at the time of inspection is compared with the initial strain amount stored in the storage medium 43, so that the tension wire 23 The presence or absence of tension reduction can be detected easily and in a short time.

9 and 10, when the size of the insertion hole 33a in the anchor plate 33 is substantially equal to the size of the insertion hole 31a in the concrete member 31, tension is applied to the anchor plate 33 via the anchor head 35. Even if a force is applied, the tension force acting on the anchor plate 33 is received by the concrete member 31 as it is, and the original bending strain is hardly generated in the anchor plate 33.
Therefore, in the present invention, in such a case, as shown in FIGS. 11 and 12, a spacer 71 is prepared to float the pressure receiving area on the anchor plate 33 to which the tension force acts from the anchor head 35 from the concrete member 31. ing.
By using this spacer 71, even when the diameters of the insertion holes 31a and 33a of the anchor plate 33 and the concrete member 31 coincide with each other, the anchor plate 33 that receives the tension force of the tension wire 23 is surely bent and distorted. Thus, it is possible to reliably detect the presence or absence of a decrease in tension in the tension wire 23.

The anchor plate 33 shown in the above embodiment is used when a ground anchor 21 is newly installed.
On the other hand, the anchor plate 73 shown in FIG. 13 can be replaced with the anchor plate 2 of the existing ground anchor 10 shown in FIG. is there.
The anchor plate 73 has an insertion hole 73a for inserting the tension wire 6 formed in a U-shaped cutout, and the other configuration is the same as that of the anchor plate 33 shown in FIG. is there. Therefore, the same parts are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 15, the anchor plate 73 in which the insertion hole 73a is formed in a U-shaped cutout is formed by pulling the tip of the tension wire 6 with a tension jack or the like in the existing ground anchor 10, and anchor plate 2 By inserting the anchor plate 73 into a slight gap 74 formed between the anchor head 8 and the anchor head 8, the tension monitor device 45 is connected as in the case of the ground anchor 21 shown in FIG. It becomes possible to measure the presence or absence of the decrease.

The position where the anchor plate 73 is inserted is not limited to between the existing anchor plate 2 and the anchor head 8.
For example, as shown in FIG. 16, it may be inserted between the existing anchor plate 2 and the concrete member 1.

However, in the existing ground anchor 10, since the extra length of the tip of the tension wire 6 is short, the anchor head 8 is slightly lifted by pulling the tip of the tension wire 6 with a tension jack or the like, and the anchor of the present invention. It is difficult to insert the plate 73.
Therefore, in the ground anchor tension detecting system 100 shown in the above embodiment, a center hole jack having the following configuration is applicable.

  As shown in FIG. 17, the center hole jack 80 can directly lift the anchor head 8 locked by the tension wire 6. The anchor head 8 is exposed by removing the oil cap (see reference numeral 36 in FIG. 1). A ram chair 81 that is placed on the surface of the concrete member 1 and is attached to the surface of the concrete member 1, and a yoke-like attachment 82 that is disposed in the ram chair 81 and that can hold the anchor head 8 is attached to the upper surface of the ram chair 81. The wire 83 connected to the attachment 82 is pulled by the joined jack portion 84. Note that a hydraulic pump 85 is connected to the jack portion 84.

In the center hole jack 80 having the above-described configuration, when the hydraulic pump 85 is operated to pull the wire 83 connected to the attachment 82 by the jack portion 84, the attachment 82 is caused by the reaction force of the ram chair 81 that presses the surface of the concrete member 1. The gripped anchor head 8 and anchor plate 2 are lifted from the concrete member 1 and lifted.
In this state, by inserting the anchor plate 73 of the present invention from the opening 81a formed at the lower end of the ram chair 81, the tension monitor device 45 is connected as in the case of the ground anchor 21 shown in FIG. Thus, it is possible to measure the presence or absence of a decrease in tension in the existing ground anchor 10.

  As described above, since the center hole jack 80 directly grips the anchor head 8 that locks the tension wire 6 instead of the tension wire 6, an existing length of the distal end portion of the tension wire 6 is short. The present invention can also be applied to the ground anchor 10, and the anchor plate 73 of the present invention can be inserted.

  In the above-described embodiment, the use example of the center hole jack 80 in the existing ground anchor 10 has been described. However, the center hole jack 80 is not limited to such a case, and a sufficient length is provided at the distal end portion of the tension wire 23. It can be used even when is secured.

In addition, the shape of the anchor plate with a sensor which can be easily attached to the existing ground anchor 10 is not limited to the shape shown in FIG.
FIG. 18 shows an anchor plate 76 to be inserted and attached to the existing ground anchor 10 later. In this case, the anchor plate 76 is divided into two half-split parts 76A and 76B. The insertion hole 76a has a semicircular arc shape. The anchor plate according to the present invention may have such a two-part structure.

In each of the above embodiments, the electrical connection between the tension monitoring device 45, the strain sensor 41, and the storage medium 43 is a wired connection using a cable with a connector.
However, instead of the connection connector 44 provided on the anchor plate 33, for example, an IC tag is provided on the anchor plate 33 and RFID (Radio Frequency Identification) is used, so that the strain sensor and the tension monitoring device 45 can be connected to each other. The connection can be wireless.
And, when the connection between the strain sensor mounted on the anchor plate and the tension monitoring device 45 is wireless, it is possible to eliminate the trouble of connecting the tension monitoring device 45 to the connector when checking the tension. Therefore, the tension check operation can be performed quickly and smoothly.

It is a longitudinal cross-sectional view of the ground anchor applied to the ground anchor tension detection system which concerns on one embodiment of this invention. It is a block diagram of a ground anchor tension detection system. It is a bottom view of an anchor plate. FIG. 4 is a side view of the anchor plate shown in FIG. 3. It is explanatory drawing of the form which connected the tension force monitor apparatus to the anchor plate. It is explanatory drawing of the set tension | tensile_strength memorize | stored in a storage medium. It is explanatory drawing of another setting method of the set tension force memorize | stored in a storage medium. It is explanatory drawing of the determination method of the tension | tensile_strength fall in a tension | tensile_strength wire. It is a longitudinal cross-sectional view which shows a structure in case the penetration hole diameter of an anchor plate and a concrete member corresponds. It is an enlarged view of the anchor plate and concrete member shown in FIG. It is a longitudinal cross-sectional view which shows the structure which additionally equipped with the spacer of the ground anchor. It is a principal part enlarged view of the anchor plate shown in FIG. It is a bottom view of other embodiments of an anchor plate according to the present invention. It is a longitudinal cross-sectional view of the existing anchor plate. It is explanatory drawing of the method of incorporating the anchor plate of FIG. 13 in the existing anchor plate. It is explanatory drawing of another method of incorporating the anchor plate shown in FIG. 13 into the existing anchor plate. It is a longitudinal cross-sectional view of a center hole jack applicable to an existing ground anchor. It is a bottom view of other embodiment of the anchor plate which concerns on this invention. It is a longitudinal cross-sectional view which shows the structure of the conventional ground anchor. It is a longitudinal cross-sectional view which shows the conventional ground anchor tension detection method.

Explanation of symbols

21 Ground anchor 23 Tension wire 33, 73, 76 Anchor plate 35 Anchor head 36 Oil cap 41 Strain sensor 43, 68 Storage medium 44 Connector for connection (waterproof connector)
45 Tensile Force Monitor Device 46 Connection Cable 47, 49 Dent 51 Waterproofing Procedure 53 Communication Cable 71 Spacer 73a, 76a Insertion Hole 100 Ground Anchor Tensile Force Detection System

Claims (7)

  An anchor plate that receives a tension force of a tension wire is equipped with a strain sensor, and a tension state of the tension wire is detected from a bending strain amount of the anchor plate detected by the strain sensor. system.   The strain sensor of the anchor plate can be electrically connected to and disconnected from the strain sensor, and includes a tension monitoring device that displays the amount of bending strain output from the strain sensor and stores it in a storage medium while being electrically connected. The ground anchor tension detection system according to claim 1.   The ground anchor tension detection system according to claim 2, wherein the storage medium is mounted on the anchor plate.   The bending strain amount stored in advance in the storage medium and the bending strain amount detected by the strain sensor are compared to detect the presence or absence of a decrease in tension in the tension wire. 3. The ground anchor tension detection system according to 3.   5. The ground anchor tension detection system according to claim 3, wherein the strain sensor and the storage medium provided on the anchor plate and the tension monitor are connected by wireless communication.   6. The spacer according to claim 1, further comprising a spacer that floats a pressure receiving area on the anchor plate on which the tension of the tension wire acts, from a concrete member formed on a ground slope or the like. The described ground anchor tension detection system. In order to float at least the anchor head locked by the tension wire from the concrete member created on the ground slope, etc.
A ram chair over the anchor head;
An attachment arranged in the ram chair and capable of gripping the anchor head;
7. The center hole jack that is coupled to the ram chair and lifts the anchor head gripped by the attachment by hydraulic pressure by the reaction force of the ram chair can be applied. Ground anchor tension detection system.

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