TW201420853A - Steel pipe insertion work steel pipe strain detection structure - Google Patents

Abstract

A hollow sensor rod (5), which is alternately formed of narrow diameter parts (7), and large diameter parts (8) which form a tiny gap with respect to the inner face of a cylindrical iron pipe (1), is inserted into the cylindrical iron pipe (1), and both ends thereof are anchored in the cylindrical iron pipe (1). Strain gauges (13) are adhered to the outer circumference faces of the narrow diameter parts (7) of the sensor rod, the lead lines whereof being inserted in the sensor rod (5) from lead line insertion holes (7a) which are opened in the narrow diameter parts (7) said lead lines being extruded from the top part of the cylindrical iron pipe (1). If the cylindrical iron pipe (1) bends and deforms due to earth movement, the sensor rod (5) bends and deforms in line with the bending and deformation of the cylindrical iron pipe (1) by the effect of the large diameter parts (8) which form the tiny gap with respect to the inner face of the cylindrical iron pipe (1). In such a circumstance, strain arises in the outer circumference faces of the narrow diameter parts (7) which is greater than the outer circumference faces of the large diameter faces (8), and it is possible to sense bending and deformation of the cylindrical iron pipes (1) with high sensitivity by the strain gauges (13) which are adhered to the outer circumferences of the narrow diameter parts (7).

Description

Steel bar strain detection structure for steel bar insertion

The present invention relates to a steel bar strain detecting structure for a steel bar insertion work in which a steel bar inserter is incorporated in a steel bar inserting work to detect the movement of a clod.

Since the previous, for the unstable slope which must consider the possibility of the collapse of the slope, a sensor having a movement for detecting the slope of the slope is performed.

For example, the bending force sensor of Patent Document 1 inserts the detecting rod into the inclined surface, and when the clod is moved and the detecting rod is bent, the condition is detected. Referring to Patent Document 1, Figure 1, Figure 2, Figure 4, and Figure 5 [0021], [0022], etc., and using the symbols of the above, the detecting rod 3 described in Patent Document 1 is attached to the cylindrical casing 9, and is disposed at the center of the center wire 29 and surrounds the center wire 29. The conductive coil 31 detects the contact of the center wire 29 with the conductive coil 31 when the detecting rod 3 is bent due to the movement of the soil block, thereby detecting the movement of the soil block.

Specifically, the center wire 29 and the conductive coil 31 are connected via the capacitor 45, and thus an alternating current circuit is formed, but a direct current circuit is not formed. Therefore, normally, only the AC detection signal detected by the PLL (phase locked loop) F/O circuit 67 is transmitted to the CPU (Central Processing Unit) 55. However, when the ground slip occurs, the detecting rod 3 is bent, and the inner center wire 29 is in contact with the conductive coil 31. Therefore, a DC circuit is formed between the center wire 29 and the conductive coil 31, and a direct current flows, and the DC current is sensed. The detector current detecting circuit (photo-coupler) 71 detects that the DC detecting signal is transmitted to the CPU 55. In this way, the detection rod 3 is bent When the center wire 29 is in contact with the conductive coil 31, the occurrence of ground slip (movement of the clods) is detected. As described above, the bending force sensor detects the ground slip only when a certain amount of ground slip is generated.

Patent Document 2 describes a pipe strain gauge for measuring the strain of the foundation (movement of the soil block) in order to prevent the rock from collapsing or the slip of the surface. Further, as shown in FIG. 11, a tip end portion 23 having a sharp distal end is attached to the front end of the measuring tube 21 which is formed by rivet connecting a plurality of short steel tubes 21a via a joint pipe 22, and is required at the position of the measuring tube 21 The strain gauge 24 is attached to the outer surface, and the measuring cable 25 of the strain gauge 24 is inserted into the inside of the measuring tube 21 to be taken out from the outside. The strain gauge 24 is protected by the protective material 26.

The above-mentioned bending force sensor and tube strain gauge are separately detected separately from the measures for reinforcing the inclined surface, but the movement of the soil block can be detected by the countermeasure of incorporating the reinforcing inclined surface, for example, the state of the steel bar inserting worker. , it is more efficient.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-148081

[Patent Document 2] Japanese Patent Publication No. 04-29806

The bending force sensor of Patent Document 1 detects the slip of the ground only when a certain amount of slippage is generated, and cannot detect the slight ground movement of the pre-sliding stage. Also, the construction is extremely complicated. Further, the bending force sensor is separately provided to the foundation separately from the countermeasure for reinforcing the slope, and therefore is not efficient, and it is preferable to detect the movement of the soil block in a state in which the reinforcing bar inserter is incorporated.

The tube strain gauge of Patent Document 2 is separately provided on the foundation separately from the countermeasure for reinforcing the slope as in Patent Document 1, but it seems that the reinforcing slope can be obtained by inserting the structure into the cylindrical reinforcement of the steel bar inserter. The effect of the movement of the clods on both sides.

However, the tube strain gauge of Patent Document 2 is originally a strain gauge that separately detects the strain of the foundation. As shown in Fig. 11, the strain gauge 24 system strain gauges are all attached to the joint pipe 22 as a large diameter portion, and thus cannot be directly Insert into the cylindrical reinforcement of the steel inserter. The reason for this is that when the cylindrical reinforcing bar is deformed accompanying the change of the foundation, in order to accurately measure the deformation, it is preferable to make the cylindrical reinforcing bar in such a manner that the deformation of the cylindrical reinforcing bar is synchronized with the deformation of the measuring instrument inside thereof. The gap between the inner surface and the measuring instrument is small, and if the strain gauge contacts the inner surface of the cylindrical reinforcing bar, accurate measurement results cannot be obtained, so the strain gauge is not required to contact the inside of the cylindrical reinforcing bar. That is, in order not to measure the noise of the friction in contact with the cylindrical reinforcing bar, the gage is required to be located away from the inner surface of the cylindrical reinforcing bar, and the deformation of the cylindrical reinforcing bar is accurately measured. Therefore, when the tube strain gauge of Patent Document 2 is simply inserted into the tubular reinforcing bar of the steel bar inserter, the strain gauge 24 is attached to the joint pipe 22 of the large diameter portion, and if the pipe strain gauge is inserted into the inside of the cylindrical steel bar Then the strain gauge 24 will contact the inner surface of the cylindrical steel bar and is not ideal. Further, the strain gauge 24 is prevented from being able to reduce the gap between the inner surface of the tubular reinforcing bar and the tube strain gauge, and the tubular reinforcing bar is deformed even if the foundation is changed, and the tube strain gauge of Patent Document 2 cannot be accurately measured. The deformation.

Further, in Patent Document 2, the strain gauge 24 is attached to the outer surface of the joint pipe 22. Therefore, when the pipe strain gauge of Patent Document 2 is inserted into the cylindrical steel bar of the steel bar inserter, the cylinder is changed due to the change of the foundation. When the steel bar is deformed, the strain gauge 24 is damaged by the inner surface of the cylindrical steel bar.

The present invention has been made in view of the above-described background, and an object thereof is to form a steel bar strain detecting structure capable of detecting a movement of a clod that can detect a bevel with a high degree of sensitivity in the above-described cylindrical reinforcing bar in which a steel bar is inserted into a steel bar. Moreover, a steel bar strain detecting structure for a steel bar insertion work with less strain gauge damage is provided.

The steel bar strain detecting structure for the steel bar insertion work of the invention of the first aspect of the present invention is characterized in that: the steel bar using the cylindrical steel bar is inserted into the tubular steel bar in the work a hollow sensor rod alternately formed with a small diameter portion and a large diameter portion, and the both ends of the sensor rod are fixed to the cylindrical reinforcing bar. The sensor rod has an outer diameter that can be bent and deformed following the bending deformation of the cylindrical steel bar. The large diameter portion of the sensor rod has a slight gap with respect to the inner surface of the cylindrical reinforcing bar when the tubular reinforcing bar is straight, and contacts the inner surface of the cylindrical reinforcing bar when the cylindrical reinforcing bar is bent. a strain gauge is attached to an outer surface of the small diameter portion of at least a portion of the sensor rod, and The wire of the strain gauge is inserted into the inside of the cylindrical reinforcing bar by being introduced into the inside of the sensor bar from a hole opened in the small diameter portion.

The second aspect of the invention is the steel strain detecting structure according to the first aspect, wherein the strain gauge is attached to a small diameter portion located in an area of 40 to 100 mm above the upper side of the design sliding surface.

The technical solution 3 is characterized in that: the steel bar strain detecting structure according to the first aspect, wherein the strain gauge is attached to a small diameter portion located in an area of 40 to 100 mm from the upper side of the design sliding surface, and a higher side portion on the upper side of the design sliding surface. The small diameter portion of the area ~200mm.

The invention of claim 2 is characterized in that the steel pipe strain detecting structure according to claim 2, wherein the small diameter portion to which the strain gauge is attached is located on the upper side of the design sliding surface and closest to the position of the design sliding surface.

The technical solution 5 is characterized in that, in the steel strain detecting structure of the third aspect, the small diameter portion to which the strain gauge is attached is located on the upper side of the design sliding surface and closest to the position of the design sliding surface, and is located at The other small diameter portion of the upper side of the small diameter portion.

The present invention is characterized in that the steel strain detecting structure according to any one of claims 1 to 5, wherein the small diameter portion to which the strain gauge is attached is provided with a waterproof coating.

The invention of claim 7 is characterized in that the steel bar strain detecting structure according to any one of claims 1 to 6, wherein the cylindrical reinforcing bar is formed by joining a plurality of short strip-shaped tubular reinforcing bars, and the short strip-shaped reinforcing bar in the part Inserting a sensor rod that is the same length as the short tubular steel bar and Fix the two ends of the sensor rod to both ends of the short tubular steel bar.

In the steel bar strain detecting structure of the present invention, both ends of the sensor rod in the cylindrical reinforcing bar are fixed to the cylindrical reinforcing bar, so that the sensor bar is also bent and deformed when the cylindrical reinforcing bar is bent and deformed. Further, the sensor rod is alternately formed with a small diameter portion and a large diameter portion, and the large diameter portion has a slight gap with respect to the inner surface of the cylindrical reinforcing bar when the tubular reinforcing bar is straight, but contacts the barrel when the cylindrical reinforcing bar is bent The inner surface of the steel bar, so that the sensor bar has an outer diameter that can be bent and deformed following the bending deformation of the cylindrical steel bar, so that the sensor bar bends when the tubular steel bar is bent, mimicking the bending deformation of the cylindrical steel bar Deformation (bending deformation of the same curvature).

On the other hand, when the same bending moment acts on the large-diameter portion and the small-diameter portion, strain (tensile strain and compressive strain) larger than the outer peripheral surface of the large-diameter portion is generated on the outer peripheral surface of the small-diameter portion. The strain signal of the strain gauge attached to the outer circumference of the small diameter portion becomes larger than the strain signal attached to the strain gauge outside the large diameter portion. In other words, by attaching the strain gauge to the small-diameter portion of the sensor rod in which the large-diameter portion and the small-diameter portion are alternately formed, it is possible to detect the bending deformation of the cylindrical reinforcing bar with a high degree of sensitivity.

As described above, the steel bar strain detecting structure of the present invention is not provided separately from the countermeasures for reinforcing the slope as disclosed in Patent Document 1 or Patent Document 2, and can detect the movement of the soil block by incorporating the steel bar inserting work, and thus Aspects are more efficient.

In addition, the bending force sensor of Patent Document 1 does not detect the slipper when the slip is generated, and the crest of the inclined foundation can be grasped based on the amount of bending deformation of the detected tubular reinforcing bar 1. The movement condition can also grasp the danger of slipping and the like.

Further, the strain gauge is present inside the cylindrical steel bar and is attached to the small diameter portion which is not in contact with the inner surface of the cylindrical steel bar, so that the gage is less damaged. Therefore, even if a protective coating is applied to the portion to which the strain gauge is attached, it is only necessary to implement a simple protective coating.

The bending deformation of the steel bar when the movement of the soil block is generated is mostly close to the sliding surface. A pattern in which a large bending deformation is generated, but according to the experimental results, it can be considered that the maximum bending deformation occurs in a region 40 to 100 mm higher than the design sliding surface, so if the strain gauge is attached as in the second embodiment, Attached to the small-diameter portion located 40 to 100 mm above the upper side of the design sliding surface, the strain gauge can detect the bending deformation of the portion of the cylindrical steel bar where the bending deformation is the greatest, so that the movement of the clod can be detected with a high sensitivity.

The design sliding surface can be set, for example, according to the result of a simple penetration test, etc., but it is impossible to strictly agree with the actual sliding surface, and it is considered that the portion where the maximum bending deformation occurs varies depending on each condition, The strain gage is attached to two parts, and the position where the cylindrical steel bar is most deformed due to the movement of the clods is not missed. According to the experimental results, as the two parts, it is preferable that the area is approximately 40 to 100 mm from the design sliding surface and approximately 140 to 200 mm from the design sliding surface.

In the case where the strain gauge is attached to one portion as in the second aspect, as in the fourth aspect, the attachment position is defined as the upper side of the design sliding surface in the foundation and the position closest to the design sliding surface. In the small diameter portion, the attachment position of the strain gauge is clarified or even standardized, and it is preferable in various aspects such as design of the attachment position of the strain gauge or work in construction.

In the case where the strain gauges are attached to two locations as in the third aspect, the strain gauge attachment positions of the two portions are preferably defined in the same sense as described above.

The reinforcing bar inserter usually connects a plurality of short strips of steel bars for construction. Therefore, it is preferable to set the sensor rods to have the same length as the short strip-shaped reinforcing bars as in the seventh aspect, and fix the both ends thereof to It is composed of two ends of short strip-shaped steel bars. In this case, the sensor rod is attached to one of the plurality of short strip-shaped reinforcing bars constituting the cylindrical reinforcing bar, and it is more efficient to position the short strip-shaped reinforcing bar of the portion on the design sliding surface.

1‧‧‧ tubular reinforcement

2‧‧‧ bearing plate

3‧‧‧ Short strip of steel bars

3‧‧‧Detector

3a‧‧‧Threaded Department

4‧‧‧ Coupler

5‧‧‧Sensor rod

5a‧‧‧ Hollow

5b‧‧‧External thread

6‧‧‧ Short strip-shaped steel bars with sensors

7‧‧‧Small diameter department

7a‧‧‧Wire insertion hole

8‧‧‧Great Path Department

9‧‧‧ Shell

12‧‧‧Fixed screw members

12a‧‧‧Wire extraction hole

12b‧‧‧Threaded Department

12c‧‧‧External thread

13‧‧‧ strain gauge

13a‧‧‧Wire

21‧‧‧Measurement tube

21a‧‧‧ Short steel pipe

22‧‧‧Connector

23‧‧‧Top cover

24‧‧‧ strain gauge

25‧‧‧ Cable

26‧‧‧Protective materials

30‧‧‧Experimental device

31‧‧‧ Lower soil trough

31‧‧‧Electrical coil

32‧‧‧Upper soil trough

33‧‧‧ pedestal

34‧‧‧Rotary axis

35‧‧‧Support material

36‧‧‧ hook

45‧‧‧ capacitor

55‧‧‧CPU

67‧‧‧F/O circuit

71‧‧‧Sensor current detection circuit

A‧‧‧ Short strip-shaped steel bars with sensors

a‧‧‧Dimensions of the long side of the rod

B‧‧‧ Short strip-shaped steel bars with sensors

P‧‧‧ Attached to the position of the strain gauge

S, S1~S5‧‧‧ Design sliding surface

Fig. 1 is a schematic cross-sectional view showing a reinforcing bar insertion portion in a reinforcing bar insertion work in which a steel bar strain detecting structure according to the first embodiment is applied to a slope.

Fig. 2 is an enlarged cross-sectional view showing the details of a short strip-shaped reinforcing bar portion of Fig. 1.

Fig. 3 is a view showing only the sensor rod of Fig. 2, (a) front view, and (b) sectional view.

Fig. 4 is a view showing the main part of Fig. 2 in an enlarged manner.

Fig. 5(a) is an enlarged cross-sectional view taken along line A-A of Fig. 4, and Fig. 5(b) is an enlarged cross-sectional view taken along line B-B of Fig. 4.

Fig. 6 is a view for explaining the action of the steel bar strain detecting structure when the movement of the soil block is generated in Fig. 1, (a) shows the state before the movement of the soil block, and (b) shows the movement of the soil block to cause the bending of the cylindrical steel bar. The state at the time of deformation.

Fig. 7 is a plan view showing a model test for confirming the performance of the steel bar strain detecting structure of the first embodiment, (a) is a side view, and (b) is a plan view.

Fig. 8 is a view showing a state in which the apparatus is tilted in an experiment using the experimental apparatus of Fig. 7.

Fig. 9 is a graph showing an experimental result of obtaining a bending deformation of a sensor bar in accordance with a bending deformation of a cylindrical steel bar by using a model test of the above experimental apparatus.

Fig. 10 is a view showing an example in which a plurality of short strip-shaped steel bars and sensor rods are prepared to correspond to the depth of the sliding surface, and (a) to (e) show examples of each combination. .

Figure 11 is a diagram illustrating a prior art, showing a tube strain gauge measuring the strain of the foundation.

Hereinafter, an embodiment of the steel bar strain detecting structure of the present invention will be described with reference to the drawings.

(First embodiment)

Fig. 1 is a schematic cross-sectional view showing a reinforcing bar insertion portion in a reinforcing bar insertion work in which a steel bar strain detecting structure according to the first embodiment is applied to a slope. In the first embodiment, the reinforcing bar insertion work is constructed as a slope stable chemical method, that is, the front end reaches a stable foundation and is solidified. In a fixed manner, a plurality of reinforcing bars 1 are inserted into the inclined surface, and the bearing plate 2 is attached to the head of each of the inserted reinforcing bars 1 to stabilize the inclined surface.

In the present embodiment, the tubular reinforcing bars are used as the reinforcing bars, and the short cylindrical reinforcing bars 3 are connected by the coupler 4 to form the cylindrical reinforcing bars 1 having a desired length. Further, the sensor rod 5 is inserted inside the cylindrical reinforcing bar 1, and both ends of the sensor rod 5 are fixed to the cylindrical reinforcing bar 1. In the first embodiment, one sensor bar 5 is inserted into one short cylindrical reinforcing bar 3, and both ends of the respective sensor bars 5 are fixed to both ends of the short cylindrical reinforcing bar 3. .

In Fig. 1, a design sliding surface (or assuming a sliding surface) of a sloped foundation is indicated by S. The design sliding surface S can be obtained by performing, for example, a simple penetration test on the slope. The simple penetration test or other test system for setting the sliding surface S may be carried out by a commonly used test method.

In the example of the figure, the two short strip-shaped reinforcing bars 3 on the surface side of the cylindrical reinforcing bar 1 are used for the short strip-shaped reinforcing bars 3 in which the sensor bars 5 are mounted, and the lower side of the short strips are cylindrical The reinforcing bar 3 is located on the sliding surface S. In the illustrated example, the sensor bar 5 is not mounted on the other short cylindrical reinforcing bar 3. The short strip-shaped reinforcing bars 3 to which the sensor rods 5 are to be mounted are referred to as short strip-shaped reinforcing bars 6 with sensors.

Figure 2 is an enlarged cross-sectional view showing the details of the short cylindrical steel bar 6 with the sensor of Figure 1, and Figure 3 is an enlarged view of the main part of the sensor bar 5 of Figure 2, (a Fig. 4 is a front view, (b) is a cross-sectional view, and Fig. 4 is an enlarged view of the main part of Fig. 2.

As the short strip-shaped steel bar 3 as an example of the figure, a so-called lock bolt can be used, and the outer diameter (screw nominal diameter) of the short strip-shaped steel bar 3 is 28.5 mm, and the short strip-shaped steel bar 3 is inside. The diameter is 13mm.

The sensor lever 5 of the illustrated example is formed with a hollow rod-shaped body having a small diameter portion 7 and a large diameter portion 8 alternately, the outer diameter of the small diameter portion 7 is 8 mm, and the outer diameter of the large diameter portion 8 is 12 mm, thin. The inner diameter of the diameter portion 7 and the inner diameter of the large diameter portion 8 are 6 mm over the entire length. Therefore, the large diameter portion 8 of the sensor rod 5 forms a small 0.5 mm (0.5 mm on one side) with respect to the inner surface of the short cylindrical steel bar 3. gap. In the present embodiment, the length of the small-diameter portion 7 in the longitudinal direction of the rod is 40 mm, and the length of the large-diameter portion 8 in the longitudinal direction of the rod is 60 mm, and the small-diameter portion 7 and the large-diameter portion 8 are repeated at intervals of 100 mm. The material of the sensor rod 5 of the present embodiment is SS (Stainless Steel) (rolled steel for general structure).

A female screw portion 3a is formed on an inner surface of both end portions of the short cylindrical reinforcing steel 3, and a male screw portion 5b is formed at both end portions of the sensor rod 5. Further, the threaded portion 12a is provided, the inner threaded portion 12b of the threaded portion 5b which is screwed to the outer surface of the sensor rod 5, and the outer surface are screwed to the internal thread portion 3a of the short cylindrical reinforcing bar 3 The screw member 12 for fixing the male screw portion 12c fixes both end portions of the sensor lever 5 to both end portions of the short cylindrical reinforcing bar 3.

Further, the method of fixing both end portions of the sensor rod 5 to both end portions of the cylindrical reinforcing bar 1 is not limited to the fixing screw member 12, and may be a bolt-nut or Then wait for various fixing methods.

The symbol p in FIGS. 2 to 6 is a position at which the respective small-diameter portions 7 of the sensor rod 5 are attached to the strain gauge 13, or a position to be attached. In particular, the symbol p in FIG. 2 indicates that the position p of the strain gauge 13 is attached to the small-diameter portion 7 at intervals of the dimension a (100 mm in the present embodiment) in the longitudinal direction of the rod.

Further, as shown in FIG. 3, a wire insertion hole 7a through which the lead wire 13a attached to the strain gauge 13 of the small diameter portion 7 is inserted into the hollow portion 5a of the sensor rod 5 is opened in each of the small diameter portions 7. The lead wire 13a inserted into the wire insertion hole 7a passes through the inside (hollow portion) 5a of the sensor lever 5, and is taken out from the top to the outside to be connected to a terminal of a strain detecting device not shown.

In order to prevent deterioration, the strain gauge attaching portion of the small-diameter portion 7 can be made of a waterproof coating formed of a resin or the like. The portion of the strain gauge 13 on the lower side of Fig. 4 is indicated by reference numeral 14 as a waterproof coating (the portion of the strain gauge 13 on the upper side is omitted from illustration). Further, a waterproof coating may be applied also including a portion of the wire 13a.

In this embodiment, the sensor rod 5 is located inside the cylindrical steel bar 1, and therefore should The water repellent treatment of the variable portion may be simpler than, for example, the protective material in Patent Document 2.

In the portion where the strain gauge 13 is actually attached to the sensor rod 5, if the strain gauge 13 is attached to only one portion, it is attached to the small diameter portion located 40 to 100 mm above the design sliding surface S. 7 can be.

The bending deformation of the steel bar when the movement of the soil block is generated is mostly in the mode of generating a large bending deformation near the sliding surface S. However, according to the experimental results, it can be considered that the upper surface of the design sliding surface S is 40 to 100 mm. Since the maximum bending deformation is performed, it is preferable to design a region in which the sliding surface S is 40 to 100 mm higher than the upper side as described above.

When the strain gauges 13 are attached to the two locations, the small diameter portions 7 that are attached to the upper side of the design sliding surface S by 40 to 100 mm and the upper side of the design sliding surface S are 140 to 200 mm. The two small portions of the small diameter portion 7 of the region may be used. In this case, the strain gauges 13 on the lower side are mainly, and the strain gauges 13 on the upper side are attached in the sense of auxiliary.

In the present embodiment, as shown in FIG. 6(a), the strain gauges 13 are attached to the two locations which are 50 mm above the design sliding surface S and 150 mm above the design sliding surface S.

The design sliding surface S can be set according to the result of, for example, a simple penetration test, but it is impossible to strictly agree with the actually generated sliding surface, and it is considered that the portion where the maximum bending deformation occurs varies depending on each condition. The strain gauge 13 is attached to two parts, and the position where the maximum deformation of the cylindrical steel bar is the largest due to the movement of the soil block can be omitted.

However, the portion to which the strain gauge 13 is attached is not limited to the above two portions. It may be one part or may be attached to the position of the strain gauge 13 which is more than the above two parts, and may be further upper side. Further, it is also conceivable to attach the strain gauge 13 to the lower side of the sliding surface S.

As described above, the relationship between the shape and the size of the short cylindrical reinforcing bars 3 and the sensor bars 5 is a proper relationship, that is, the sensor bars 5 are alternately formed in the shape of the small diameter portion 7 and the large diameter portion 8, and The large diameter portion 8 forms 0.5 mm (0.5 mm on one side) with respect to the inner surface of the short cylindrical steel bar 3 A tiny gap. Therefore, when the short cylindrical reinforcing bar 3 is bent, the sensor bar 5 smoothly follows the bending of the short cylindrical reinforcing bar 3, and is deformed in accordance with the bending deformation of the short cylindrical reinforcing bar 3 (becomes substantially the same curvature). Bending deformation.

It is assumed that if the gap between the large diameter portion 8 of the sensor rod 5 and the inner surface of the short cylindrical steel bar 3 is too small, the large diameter portion 8 may be due to the friction with the inner surface of the short cylindrical steel bar 3. When it is in the fixed state, the movement to the long side direction is restrained, so that the bending deformation of the sensor rod 5 does not mimic the possibility of bending deformation (not the same curvature) of the short cylindrical steel bars 3 or the strain gauge 13 The output signal does not reflect the possibility of bending deformation. Further, in the case where the gap is excessively large, the possibility that the bending deformation of the sensor lever 5 does not follow the bending deformation of the short cylindrical reinforcing bar 3 is also high. However, since the relationship between the shape and the size of the short cylindrical reinforcing bar 3 and the sensor bar 5 is as described above, when the short cylindrical reinforcing bar 3 is bent, the sensor bar 5 follows the bending of the short cylindrical reinforcing bar 3. Deformation and bending deformation.

Furthermore, the followability of the above-described bending deformation is described as the relationship between the sensor rod 5 and the short cylindrical reinforcing bars 3, but it is also the relationship between the sensor rod 5 and the cylindrical reinforcing bars 1.

In the above-described reinforcing steel strain detecting structure, both ends of the sensor rod 5 in the short cylindrical steel bar 3 of the cylindrical reinforcing bar 1 are fixed to both ends of the short cylindrical reinforcing steel 3, so when the cylindrical reinforcing bar 1 When the bending deformation causes the short cylindrical reinforcing bar 3 to be bent and deformed, the sensor bar 5 is also bent and deformed. Further, the small diameter portion 7 and the large diameter portion 8 are alternately formed in the sensor rod 5, and the large diameter portion 8 has a small inner surface with respect to the inner surface of the short cylindrical steel bar 3 when the short cylindrical steel bar 3 is straight. The gap is in contact with the inner surface of the short cylindrical reinforcing bar 3 when the short cylindrical reinforcing bar 3 is bent, so that the sensor bar 5 has an outer diameter which can be bent and deformed following the bending deformation of the short cylindrical reinforcing bar 3. . Therefore, when the short cylindrical steel bar 3 is bent, the sensor bar 5 is bent and deformed (bending deformation of the same curvature) in accordance with the bending deformation of the short cylindrical steel bar 3. In other words, when the cylindrical reinforcing bar 1 is bent, the sensor bar 5 is bent and deformed (bending deformation of the same curvature) in accordance with the bending deformation of the cylindrical reinforcing bar 1.

On the other hand, in the case where the same bending moment acts on the small diameter portion 7 and the large diameter portion 8 In the outer peripheral surface of the small-diameter portion 7, the strain (tensile strain and compressive strain) larger than the outer peripheral surface of the large-diameter portion 8 is generated. Therefore, the strain signal of the strain gauge 13 attached to the outer periphery of the small-diameter portion 7 is larger than the assumption. The strain signal of the strain gauge when attached to the outer circumference of the large diameter portion 8. In other words, since the strain gauge 13 is attached to the small-diameter portion 7 of the sensor rod 5 in which the small-diameter portion 7 and the large-diameter portion 8 are alternately formed, the bending deformation of the cylindrical reinforcing bar 1 can be detected with high sensitivity. .

As described above, the steel bar strain detecting structure of the present embodiment is not provided separately from the countermeasure for reinforcing the slope as in Patent Document 1 or Patent Document 2, and the movement of the clods can be detected by the state in which the reinforcing bar inserts are incorporated. It is more efficient in all aspects.

Moreover, unlike the bending force sensor of Patent Document 1, the slider is detected only when a certain amount of ground slip is generated, and the clods of the inclined foundation can be grasped based on the amount of bending deformation of the detected tubular reinforcing bar 1. The movement condition can also grasp the danger of slipping and the like.

The action of the above-described reinforcing steel strain detecting structure in the case where the unstable layer of the inclined soil foundation is moved. Fig. 6(a) shows a state in which there is no movement of the soil block, and Fig. 6(b) shows a state in which the movement of the soil block is generated. When the clod is moved, the cylindrical reinforcing bar 1 is subjected to bending deformation, but it is assumed that the portion in the stable foundation deeper than the sliding surface S of the cylindrical reinforcing bar 1 is not moved at all, in this case, the cylindrical reinforcing bar 1 is from Fig. 6 The state of (a) produces, for example, a bending deformation as shown in Fig. 6(b). In other words, the portion that is higher on the sliding surface S and closer to the sliding surface S has a larger bending deformation, and if it is sufficiently away from the sliding surface S, it moves in a substantially straight state.

In the case of the bending deformation as shown in the figure, the strain gauge 13 attached to the position 50 mm from the upper side of the sliding surface S substantially corresponds to the largest bending deformation portion of the cylindrical reinforcing bar 1, and the strain gauge 13 outputs a large strain. The signal, so that the movement of the clods can be detected with high precision. However, it is assumed that the sliding surface S is unlikely to be rigorously agreed with the actually produced sliding surface, and that the maximum bending deformation portion is slightly offset depending on each condition, and therefore is also provided on the upper side for the purpose of auxiliary assistance. The strain gauge 13 is such that the movement of the clods can be more reliably detected by the strain signals from the two strain gauges 13.

A model experiment performed to confirm the performance of the steel bar strain detecting structure of the present embodiment will be described.

As shown in FIG. 7 and FIG. 8, the experiment is performed by: preparing an experimental device 30 formed with a soil groove 31 fixed to the lower portion of the pedestal 33 and slidable relative to the lower soil groove 31. The two steel box-shaped soil grooves of the upper soil tank 32 are stacked in two stages to form a simulated foundation; the pedestal 33 is inclined to generate simulated ground movement. The sand is placed so that the lower soil groove 31 is a dense foundation having a depth of 0.5 m, a width of 1 m, and a length of 1 m, and the upper soil groove 32 is a foundation having a depth of 1 m, a width of 1 m, and a length of 1 m, and is provided at the center of the soil tank. The test was carried out by attaching a pressure-receiving plate 2 to the head of the cylindrical steel bar 1 by a cylindrical steel bar 1 (a short-bar-shaped steel bar 6 with a sensor attached) to which the sensor rod 5 was attached.

The lower end of the cylindrical reinforcing bar 1 is fixed to the bottom of the lower soil groove 31. The moving portion (the interface between the lower soil groove 31 and the upper soil groove 32) is a Teflon (DuPont registered trademark) sheet and a flat roller in such a manner as to minimize friction.

The tubular reinforcing bar 1 and the sensor bar 5 are of the structure and shape described in FIGS. 2 to 5, but the strain gauge 13 is attached to the sliding surface S of each of the cylindrical reinforcing bar 1 and the sensor bar 5 (the interface between the lower soil groove 31 and the upper soil groove 32) is 55 mm above. The pedestal 33 on which the lower soil groove 31 is placed is horizontally supported by the rotating shaft 34 on one end side and the supporting material 35 on the other end side, and the other end side is lifted and lowered by the hook 36 of the crane to have a desired inclination. .

The graph of Fig. 9 is obtained by bending the cylindrical reinforcing bar 1 and the sensor bar 5 when the lower soil groove 31 and the upper soil groove 32 are inclined as shown in Fig. 8 in the experiment conducted using the above-described experimental device 30. The relationship of the strain. The horizontal axis is the strain ε of the cylindrical reinforcing bar 1 and the vertical axis is the strain ε of the sensor bar 5 .

As shown in the graph, it is understood that the bending strain of the cylindrical reinforcing bar 1 and the sensor bar 5 detected by the strain gauge 13 attached to the position 55 mm above the sliding surface S is almost the same, and both are bent and deformed in the same manner. That is, it is understood that the small diameter portion 7 and the large diameter portion 8 are alternately formed by the sensor rod 5, and there is a slight gap between the large diameter portion 8 and the inner surface of the cylindrical reinforcing bar 1 In the structure, when the cylindrical reinforcing bar 1 is bent, the sensor bar 5 is bent and deformed in accordance with the bending deformation of the cylindrical reinforcing bar 1 (bending deformation of the same curvature).

Furthermore, the specific shape and size of the sensor rod 5 of the present embodiment is not limited to the above-described shape size.

The shape of the sensor rod 5 is set such that the sensor rod 5 is bent as accurately as possible in accordance with the bending deformation of the cylindrical reinforcing bar 1, but in particular, the outer diameter portion of the sensor rod 5 and the cylindrical reinforcing bar The relationship of the inner diameter of 1 is a key element, and the gap between the outer peripheral surface of the large diameter portion and the inner surface of the cylindrical reinforcing bar should be appropriately set. Further, the relationship between the length of the large diameter portion and the length of the small diameter portion must also be appropriately set.

Further, the sensitivity for detecting the bending deformation is largely related to the difference between the outer diameter of the large diameter portion and the outer diameter of the small diameter portion.

In the present embodiment, the strain gauge 13 is attached only to the small-diameter portion 7 of two of the plurality of small-diameter portions 7 of the short cylindrical reinforcing bars 3 corresponding to the bending deformation portion, but the strain gauge 13 is attached. The site is not limited to two sites and can be appropriately selected. However, if the strain gauge 13 is attached to the left and right of the two portions in the vicinity of the sliding surface S, the bending deformation can be detected as appropriate, and the hollow portion 5a of the sensor rod 5 penetrating the wire 13a is also present. The case where the diameter is thinner is 6 mm, so that it is not necessary to uselessly increase the number of the strain gauges 13.

Further, in the present embodiment, the sensor rod 5 is attached to the surface side of the plurality of short cylindrical steel bars 3 of the cylindrical reinforcing bar 1, but may correspond to only the vicinity of the sliding surface S. A short strip-shaped reinforcing bar 3 is attached to the sensor rod 5. Further, the sensor rod 5 may be attached to all of the short cylindrical reinforcing bars 3 of the cylindrical reinforcing bar 1.

Further, the tubular reinforcing bars 1 are actually connected to a plurality of short cylindrical reinforcing bars 3 to have a desired length, but one cylindrical reinforcing bar having a desired length may be used.

(Second embodiment)

In the first embodiment described above, two short-length tubular reinforcing bars 6 with the same length of the sensor are connected as a sliding surface (design sliding surface) S and extend upward from the sliding surface S. The strip-shaped steel bar 6 with the sensor is attached, but according to the depth position of the sliding surface S, a plurality of lengths of short strip-shaped steel bars with sensors are used, and the appropriate combination is used to constitute A short cylindrical steel bar 6 with a sensor attached to the sliding surface S and which is a portion higher than the sliding surface S.

For example, as shown in FIG. 10, if two types of short strip-shaped reinforcing bars A with sensors and 1.5 m short strip-shaped reinforcing bars B with sensors are prepared, the sliding surface can be used. The depth position corresponds to the sliding surface S of any depth position by the combination of the following (for example, any one of the sliding surfaces S1 to S5 of FIG. 10), that is, only one 1 m is used as in (a) Short strip-shaped reinforcing bar A with sensor, or as long as (b) only one 1.5m short strip-shaped reinforcing bar B with sensor, or as (c) connecting two 1m attached a short strip-shaped reinforcing bar A with a sensor, or a short strip-shaped reinforcing bar A with a sensor attached to a 1 m short strip-shaped reinforcing bar B with a sensor as in (d), Or, as in (e), connect two 1.5m short strip-shaped steel bars B with sensors.

Furthermore, the sensor bars 5 may not be mounted on all of the short cylindrical reinforcing bars 3 on the surface side of the sliding surface S, but only the short cylindrical steel bars 3 located on the sliding surface S may be mounted with the sensor bars. 5.

The embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit and scope of the invention.

For example, in the above embodiment, the pressure receiving plate 2 is attached to the head of the cylindrical reinforcing bar 1 to stabilize the inclined surface. However, the present invention can also be applied to inserting only the cylindrical reinforcing bar 1 without using the bearing plate. The situation of the construction law to the foundation.

Moreover, it is also applicable to the slope-stable chemical method in which the pressure receiving plate 2 is used as in the above embodiment, and the inclined surface between the heads of the adjacent cylindrical reinforcing bars 1 is connected by a cable or the like on the inclined surface.

[Industrial availability]

According to the present invention, it is possible to incorporate steel which can detect the movement of the clods with a high degree of sensitivity The rib strain detecting structure, in addition, can be used as a steel bar strain detecting structure for a steel bar insertion work which is less damaged by the installed strain gage.

1‧‧‧ tubular reinforcement

2‧‧‧ bearing plate

3‧‧‧ Short strip of steel bars

5‧‧‧Sensor rod

5b‧‧‧External thread

6‧‧‧ Short strip-shaped steel bars with sensors

7‧‧‧Small diameter department

7a‧‧‧Wire insertion hole

8‧‧‧Great Path Department

12‧‧‧Fixed screw members

13‧‧‧ strain gauge

S‧‧‧ Design sliding surface

P‧‧‧ Attached to the position of the strain gauge

Claims (7)

A steel bar strain detecting structure for steel bar insertion work, characterized in that: in the inside of the cylindrical steel bar in which a steel bar is inserted into a steel bar, a hollow sensing in which a small diameter portion and a large diameter portion are alternately formed is inserted a rod, and fixing both end portions of the sensor rod to the cylindrical reinforcing bar, wherein the sensor rod has an outer diameter that can be bent and deformed following a bending deformation of the cylindrical reinforcing bar, and the sensor rod The large diameter portion has a slight gap with respect to the inner surface of the cylindrical reinforcing bar when the tubular reinforcing bar is straight, and is in contact with the inner surface of the cylindrical reinforcing bar when the cylindrical reinforcing bar is bent, and the sensor rod is A strain gauge is attached to an outer surface of at least a part of the small diameter portion, and the wire of the strain gauge is inserted into the tube by being introduced into the inside of the sensor rod from a hole opened in the small diameter portion. The inside of the steel bar. The steel bar strain detecting structure for the reinforcing bar insertion work of claim 1, wherein the strain gauge is attached to the small diameter portion located in an area of 40 to 100 mm above the upper side of the design sliding surface. The steel bar strain detecting structure of the reinforcing bar insertion work of claim 1, wherein the strain gauge is attached to the small diameter portion located in an area of 40 to 100 mm above the upper side of the design sliding surface, and is located above the design sliding surface. The above-mentioned small diameter portion of the region of 140 to 200 mm. The steel bar strain detecting structure for reinforcing steel bar insertion according to claim 2, wherein the small diameter portion to which the strain gauge is attached is a small diameter portion located above the design sliding surface and closest to the design sliding surface. The steel bar strain detecting structure of the steel bar insertion work of claim 3, wherein the above is attached The small-diameter portion of the strain gauge is located on a larger diameter portion that is located above the design sliding surface and closest to the design sliding surface, and another small diameter portion that is located on the upper side of the smaller diameter portion. The steel bar strain detecting structure for reinforcing steel insertion work according to any one of claims 1 to 5, wherein the small diameter portion to which the strain gauge is attached is provided with a waterproof coating. The steel bar strain detecting structure for reinforcing steel insertion work according to any one of claims 1 to 6, wherein the cylindrical steel bar is formed by connecting a plurality of short strip-shaped steel bars, and the short strip-shaped steel bar in the part is The sensor rod is inserted into the length of the short cylindrical steel bar, and both ends of the sensor rod are fixed to both ends of the short cylindrical steel bar.