JP6785587B2 - Consolidation material filling status detection method and consolidation material filling status detection system - Google Patents

Description

The present invention relates to a ground improvement detection method and a ground improvement detection system.

When excavating a tunnel, various auxiliary construction methods such as AGF method, side pile, leg pile, etc. are known, in which a long pipe is placed in the ground around the tunnel and injection is performed from inside the long pipe to improve the ground. ing. For example, the AGF method is a method of reinforcing the outer peripheral ground of the tunnel excavation portion in front of the face in advance (see, for example, Patent Documents 1 and 2). In this construction method, a plurality of long steel pipes of about 10 to 20 m are produced in the ground by connecting a plurality of steel pipes of about 3 m, and these are cast using a general-purpose drill jumbo. At this time, the plurality of long steel pipes are driven in an umbrella shape with respect to the reinforcing area on the outer circumference in front of the face. That is, a plurality of long steel pipes are driven so as to spread toward the excavation direction of the tunnel. Then, after placing the long steel pipe, a chemical solution such as urethane or silica resin or a solidifying material such as a cement-based injection material is injected into each long steel pipe. The solidifying material injected in this way seeps out of each long steel pipe, reinforces the ground around the long steel pipe, and as a result, suppresses loosening of the ground. At this time, the properties and the degree of reinforcement of the ground in front of the face were predicted by analysis and the like, and it was confirmed in the implementation work that the reinforcement area was constructed by controlling the injection amount and injection pressure.

Japanese Patent No. 3882118 Japanese Patent No. 3101550 Japanese Unexamined Patent Publication No. 2015-158437

However, for example, as shown in FIG. 15, when a brittle region with many cracks D exists in the ground, even if an appropriate amount of the binder is injected, the injected binder is reinforced by the cracks in the reinforcing region C. There is a possibility that the binder will not be sufficiently injected into the reinforcing region C due to the outflow to the outside. Therefore, Patent Document 3 proposes a method using a dedicated exploration device or blasting as a method for exploring the condition of the ground in front of the face. However, if this is done, there is a problem that the equipment required for exploration becomes very large. In addition, since it takes time to analyze the data and estimate the change in rock quality in such exploration, it is not easy to incorporate it into the long steel pipe driving cycle when the AGF method is used. These problems are also a problem in the side pile and leg pile that improve the ground around the tunnel by using the casting and injection of long steel pipes as in the AGF method.

The present invention has been made to solve the above problems, and it is possible to easily and surely monitor the filling state of the binder injected into the ground around the tunnel when excavating the tunnel. It is an object of the present invention to provide an improved detection method and a ground improvement detection system.

The ground improvement detection method according to the present invention includes a step of preparing a plurality of long pipes having at least one through hole formed on the outer peripheral surface, and placing the plurality of long pipes in the ground around the tunnel. A step, a step of forming at least one detection hole in the vicinity of at least one of the plurality of long tubes, and at least one detection sensor having a light emitting portion and a light receiving portion in the detection drill. A step of inserting, a step of injecting a binder into each of the long pipes, and a step of reinforcing the ground around the long pipe with the binder flowing out from the through hole of the long pipe. The light receiving unit receives the light emitted from the light emitting unit of the detection sensor, and the light receiving unit includes a step of measuring the intensity of the light received by the light receiving unit.

According to this configuration, when the solidifying material is injected into the long pipe, the solidifying material that has flowed out from the through hole of the long pipe permeates the ground around the long pipe, and in this process, The solidifying material also flows into the detection holes formed near the long tube. At this time, in the detection drilling, the light emitted from the light emitting portion of the detection sensor is received by the light receiving portion, but as the detection drilling hole is filled with the solidifying material, the light is received by the light receiving portion. When the intensity of light decreases and the holes for detection are completely filled with the solidifying material, the light receiving part and the light emitting part are blocked by the solidifying material, so that the intensity of the light received by the light receiving part is reduced. It becomes almost zero. This makes it possible to confirm that the binder has penetrated into the ground around the long pipe. On the other hand, if there are voids or cracks in the ground around the long pipe, the solidifying material that has flowed out of the long pipe will flow into the cracks, so there is sufficient solidifying material in the holes for detection. It does not flow. In such a state, the intensity of the light received by the light receiving portion of the detection sensor does not become zero, or the intensity of the light does not decrease, so that there may be cracks or the like around the long tube. I understand.

Therefore, the condition of the ground can be confirmed without using a large-scale device. Further, since it can be incorporated into the construction of the long tip receiving method, it is possible to prevent the construction time from increasing excessively even though the detection is performed in parallel.

In the step of measuring the light intensity, the circumference of the long tube is determined from the relationship between the injection amount of the binder injected into the long tube and the intensity of the light received by the light receiving portion of the detection sensor. You can check the reinforcement status of the ground.

According to this configuration, for example, when there are no cracks in the ground around the long tube, the injection amount of the binder to be injected into the long tube and the light received by the light receiving portion of the detection sensor. If the relationship with the light intensity is measured in advance, compared to this relationship, when the light intensity received is low with respect to the injection amount of the binder, cracks or the like will occur in the ground around the long tube. It can be easily determined that it may exist.

Further, in the step of inserting the detection sensor, a plurality of detection sensors are inserted into the detection holes, and the light emitting portion and the light receiving portion of each detection sensor are arranged at different positions in the hole forming direction. Can be done.

According to this configuration, by measuring the intensity of the light received by the plurality of detection sensors, it is possible to confirm at which position in the hole forming direction of the detection hole the crack exists.

Further, the step of inserting the detection sensor includes a step of inserting an auxiliary long tube into the detection hole, a step of inserting at least one detection sensor into the auxiliary long tube, and the detection sensor. A step of extracting the auxiliary long tube from the detection hole while leaving the auxiliary long tube in the detection hole can be provided.

According to this configuration, since the detection sensor is inserted inside the auxiliary long tube, the detection sensor can be easily inserted at a desired position of the hole for detection.

Further, in the above-mentioned ground improvement detection method, the detection sensor is formed in a long shape having the light emitting portion and the light receiving portion at the tip, and the auxiliary long tube connects a plurality of tube members in the axial direction. The outer peripheral surface of each pipe member is formed with a slit communicating with the rear end opening of each pipe member, and the detection sensor can pass through the slit. it can.

This configuration has the following advantages: First, the auxiliary long tube is pulled out from the hole for detection by a drifter or the like. At this time, the drifter is attached to the rear end opening of the auxiliary long tube. Therefore, if a slit is formed on the outer peripheral surface of the steel pipe as described above, the rear end portion of the detection sensor can be pulled out from the slit even when the auxiliary long pipe is connected to the drifter. Then, when the auxiliary long tube is pulled out by the drifter, the detection sensor may be pulled out at the same time. In order to prevent this, if the end of the detection sensor pulled out from the slit is pushed toward the inner end of the drilling hole, it is possible to prevent the detection sensor from being pulled out together with the long tube for inserting the sensor. ..

In the above-mentioned ground improvement detection method, various substances can be used as the detection sensor. For example, an optical fiber sensor formed in a long shape having the light emitting portion and the light receiving portion at the tip can be used.

The ground improvement detection system according to the present invention is a plurality of long pipes having at least one through hole formed on the outer peripheral surface, and includes a plurality of long pipes cast in the ground around the tunnel. An at least one detection sensor inserted into at least one detection hole formed in the vicinity of at least one of a plurality of long tubes placed in the ground and having a light emitting portion and a light receiving portion. It has.

According to the present invention, when excavating a tunnel, it is possible to easily and surely monitor the filling state of the solidifying material injected into the ground around the tunnel.

It is sectional drawing which shows the schematic structure of the long tip receiving method to which the ground improvement detection method of this invention was applied. It is a vertical sectional view of FIG. It is an assembly drawing of a long steel pipe. It is a side view of a drilling bit and a bit adapter. It is sectional drawing which shows the driving of the long steel pipe of FIG. It is sectional drawing which shows an example of the method of injecting a solidifying material into a long steel pipe. It is sectional drawing which shows an example of the method of injecting a solidifying material into a long steel pipe. It is a side view of the auxiliary steel pipe. It is a perspective view which shows the optical fiber sensor. It is sectional drawing which shows the installation method of the optical fiber sensor of FIG. It is sectional drawing which shows the installation method of the optical fiber sensor of FIG. It is a cross-sectional view of the ground where a long steel pipe and an optical fiber sensor are placed. This is an example of a monitor that graphs the relationship between the intensity of light received by an optical fiber sensor and the elapsed time. It is sectional drawing which shows the construction example of a long steel pipe. It is sectional drawing of the ground where a long steel pipe was placed.

Hereinafter, an embodiment in the case where the ground improvement detection method according to the present invention is applied to the long tunnel receiving method (so-called AGF method) will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of a long tip receiving method according to the present embodiment, and FIG. 2 is a cross-sectional view of the vicinity of the tunnel face of FIG. In the following, for convenience of explanation, the back end side of the hole into which the long steel pipe is inserted is the "tip side" or "leading side", and the opposite side is the "base end side" or "rear end". Sometimes referred to as "side". Further, the extending direction of the drilled hole and the corresponding extending direction of the long steel pipe may be referred to as an axial direction. In addition, the direction may be indicated by the wording of the radial direction or the circumferential direction around this axial direction. In the following, an example of constructing a long steel pipe on the inner wall surface of a new tunnel will be described.

<1. Outline of long tunnel construction method>
First, a general tunnel long tip receiving method will be described. As shown in FIGS. 1 and 2, in the general long tip receiving method, first, the mirror surface sprayed concrete 11 is applied to the mirror surface 12 of the tunnel face 1 to temporarily press the mirror surface 12. Then, a long steel pipe 48 is driven into the mirror surface 12. Similarly, a plurality of long steel pipes 2 are driven along the outer edge of the face 1. These plurality of long steel pipes 2 are cast along the outer edge of the face 1 in an arch shape and so as to form a predetermined elevation angle θ with the tunnel axial direction X. Moreover, this point will be described in more detail.

The long steel pipe 2 is formed as follows. FIG. 3 is an assembly drawing of a long steel pipe. As shown in the figure, the long steel pipe is formed by connecting a plurality of steel pipes 21 formed in a cylindrical shape. Female threads are formed at both ends of each steel pipe 21 in the axial direction, and a plurality of steel pipes 21 are connected in the axial direction by a screw type coupler 23 or the like. However, the configuration of the long steel pipe 2 is not limited to this. For example, a female screw is formed at the tip of each steel pipe 21, a male screw is formed at the rear end, and the male screw and the female screw are screwed together. By combining them, a plurality of steel pipes 21 can be connected. Further, a plurality of discharge holes 22 are formed in each steel pipe 21, and the internal space of the steel pipe 21 and the outside communicate with each other through the discharge holes 22.

The long steel pipe 2 thus formed is driven into the ground as described below. This point will be described with reference to FIG. FIG. 4 is a side view of the drilling bit and the bit adapter.

As shown in FIG. 4, a tubular casing shoe 62 is attached to the tip of the long steel pipe 2 by screw tightening or welding, and a bit adapter 41 is formed inside the casing shoe 62 due to drilling vibration. It fits in a form that allows axial movement. A drilling bit 3 for excavating the ground is attached to the tip of the bit adapter 41 and protrudes from the casing shoe 62. A plurality of blades 31 are provided at the tip of the drilling bit 3, and the ground is excavated by the blades 31. Further, a rope screw-shaped female screw is formed at the rear portion of the bit adapter 41, and a drilling rod 61 is screwed into the female screw. Then, the drilling rod 61 passes through the inside of the long steel pipe 2 and is connected to a drilling machine 6 such as a drill jumbo arranged behind the long steel pipe 2 (see FIG. 5).

Further, the drilling bit 3 and the bit adapter 41 are engaged with each other by a dead end fitting keyway, and when the drilling rod 61 is driven in the forward rotation together with the bit adapter 41 by the drilling machine 6, the engaged state is maintained. , When reversed, the bit adapter 4 is separated from this keyway.

Next, a method of placing the long steel pipe 2 configured as described above will be described with reference to FIG. First, the drilling bit 3 and the bit adapter 4 are connected, and the drilling bit 3 is arranged at the tip of the steel pipe 21 constituting the leading portion of the long steel pipe 2. Further, a known drilling machine 6 as shown in FIGS. 1 and 5 is prepared. A drilling rod 61 is attached to the drilling machine 6 via a shank rod (not shown), and the tip of the drilling rod 61 is connected to the drilling bit 3 via a bit adapter 4. A spline shaft is attached to the rear end of the shank rod, and this spline shaft is connected to the drive shaft of the drilling machine 6. That is, the drilling bit 3 is spline-coupled to the drive shaft of the drilling machine 6 via the drilling rod 61 inserted into the long steel pipe 2 and the bit adapter 4, and the rotational force, striking force, and thrust are transmitted. ..

Then, the tip surface of the drilling bit 3 is brought into contact with the ground surface, and the drilling machine 6 is driven to excavate the ground. At this time, as described above, the long steel pipe 2 is driven so as to form a predetermined elevation angle θ with the tunnel axial direction X. In this way, the drilling is formed, but since the drilling bit 3 is connected to the long steel pipe 2, the long steel pipe 2 also enters the ground together with the drilling bit 3. At this time, since the outer diameter of the drilling bit 3 and the outer diameter of the long steel pipe 2 are substantially the same, the long steel pipe 2 moves forward while being in contact with the inner wall surface of the drilling. In this way, when the leading steel pipe 21 is brought into the ground, the second steel pipe 21 is connected to the leading steel pipe 21 by the coupler 23, and the drilling rod 61 is similarly connected to the second steel pipe to drill and punch. Continue the installation work. In this way, as shown in FIG. 1, when the rear end of the long steel pipe 2 having a predetermined length reaches the surface of the ground, the drilling machine 6 is stopped. Following this, the drilling machine 6 is reversed, the bit adapter 4 is removed from the drilling bit 3, and the bit adapter 4 and the drilling rod 61 are pulled out from the long steel pipe 2. That is, the drilling bit 3 and the long steel pipe 2 are left behind in the ground.

Subsequently, the binder is injected into the long steel pipe 2. At this time, various binders such as cement-based binders, urethane-based binders, and water glass-based binders can be used as the binder. First, a case where a cement-based solidifying material is used will be described. In this case, for example, as shown in FIG. 6, the rear end portion of the long steel pipe 2 is sealed with the mouth valve 27, and a plurality of injection pipes 29 penetrating the mouth valve 27 are connected to the long steel pipe 2. insert. The plurality of injection pipes 29 have different lengths, and the tip openings of the respective injection pipes 29 are arranged at different positions in the axial direction of the long steel pipe 2. Then, when the binder is injected into each injection pipe 29, the long steel pipe 2 is filled with the binder. At this time, since the tip openings of the plurality of injection pipes 29 are arranged at different positions in the axial direction, the binder is filled at a plurality of places inside the long steel pipe 2. However, the water glass-based binder can also be used in the same manner as the cement-based binder.

On the other hand, when a urethane-based binder is used, for example, as shown in FIG. 7, a plurality of packers 45 are arranged inside the long steel pipe 2. Each packer 45 is arranged at a plurality of positions in the axial direction of the long steel pipe 2 and is in close contact with the inner wall surface of the long steel pipe 2. As a result, the internal space of the long steel pipe 2 is partitioned into a plurality of regions 20 along the axial direction. Then, a plurality of injection pipes 29 are inserted from the mouth valve 27 so that the tip openings of each injection pipe 29 are arranged in each of the partitioned regions 20, and then the binder is injected. As a result, the binder is uniformly filled in each region 20. However, the above-mentioned cement-based binder and water glass-based binder can also be used together with the packer.

As described above, the long steel pipe 2 is filled with the solidifying material regardless of which method is used, but when the solidifying material is further injected, the solidifying material is discharged from the discharge holes 22 formed in each steel pipe 21. It flows out to the outside of the long steel pipe 2. As shown in FIG. 1, the solidifying material S that has flowed out permeates the ground around the long steel pipe 2 to reinforce the ground. After that, the mirror surface 12 is excavated, and the long steel pipe 48 that appears in the tunnel is blasted or mechanically excavated while crushing the tunnel in sequence. Then, after constructing the support 5 on the inner wall surface of the excavated tunnel, the sprayed concrete 7 is placed. In this way, the excavation of the tunnel is advanced while repeating the driving of the long steel pipe 2 and the excavation of the mirror surface 12.

By the way, if the solidifying material is injected as described above and the solidifying material is infiltrated into the ground around the long steel pipe 2, the ground is reinforced, but there are voids and cracks in the ground. In this case, the solidifying material may flow into the voids or cracks, and the solidifying material may be dispersed in a place away from the periphery of the long steel pipe 2. As a result, the circumference of the long steel pipe 2 may not be sufficiently reinforced by the binder. Therefore, in the present embodiment, it is confirmed whether or not the solidifying material is filled around the long steel pipe 2 by the following method.

<2. How to check the filling of the binder>
In the method for confirming the filling of the solidifying material according to the present embodiment, the auxiliary long steel pipe 8 and the long optical fiber sensor 9 are placed in the ground prior to the injection of the solidifying material described above, and then. When the binder is injected, the optical fiber sensor 9 is used to confirm the filling of the binder. In the following, the auxiliary long steel pipe 8 and the optical fiber sensor 9 will be described first, and then the confirmation method will be described.

<2-1. Auxiliary long steel pipe ＞
As shown in FIG. 8, the auxiliary long steel pipe 8 is formed by connecting a plurality of cylindrical steel pipes 81 in the axial direction (three in this embodiment). The method of connecting the plurality of steel pipes 81 is not particularly limited, but can be configured in the same manner as in the case of forming the long steel pipe 2 described above.

However, at least one slit 82 is formed at the rear end of each steel pipe 81. Each slit 82 extends forward in the axial direction from the opening at the rear end of the steel pipe 81. Further, since the optical fiber sensor 9 or a bundle thereof, which will be described later, is passed through the slit 82, the width needs to be larger than the outer diameter of the sensor 9 or the bundle thereof.

A cone member 83 is attached to the tip of the auxiliary long steel pipe 8. The cone member 83 is composed of a conical main body 831 and a shaft member 832 attached to the lower surface of the main body 831, and the shaft member 832 is detachably attached to and detachable from the tip opening of the auxiliary long steel pipe 8. Will be inserted.

<2-2. Optical fiber sensor ＞
Next, the optical fiber sensor 9 will be described. As the optical fiber sensor used in the present embodiment, a known one can be used. For example, as shown in FIG. 9A, a long two-core plastic optical fiber sensor can be used. That is, this sensor 9 integrally fixes the long light-receiving optical fiber 91 and the light-emitting optical fiber 92, and receives the light emitted from the light-emitting portion 921 at the tip of the light-emitting optical fiber 92. The light receiving unit 911 at the tip of the optical fiber 91 receives light, and the intensity of the received light is measured. Further, as will be described later, in the present embodiment, a plurality of optical fiber sensors 9 having different lengths are used. That is, as will be described later, a bundle of a plurality of optical fiber sensors 9 is used so that the tip portions are arranged at different positions along the axial direction of the detection drilling hole 15 (for example, FIG. 10C). reference).

Further, the optical fiber sensor 9 can be configured as shown in FIG. 9B. That is, the tip surface of the light receiving optical fiber 91 and the tip portion of the light emitting optical fiber may be cut diagonally so that the light emitting portion 921 and the light receiving portion 911 face each other more. With this configuration, the optical fiber sensor 9 can measure the intensity of the light received more sensitively even when there is turbid water in the bore hole due to spring water or the like.

Next, a method for confirming the filling of the binder will be described. First, as shown in FIG. 10A, a hole for detection 15 is formed around the long steel pipe 2. The detection drilling hole 15 selects some of the long steel pipes 2 that have been cast and is formed in parallel with the long steel pipe 2 in the vicinity of them, preferably at an intermediate position between the adjacent long steel pipes 2 and 2. Therefore, it is not necessary to form the detection holes 15 in the vicinity of all the long steel pipes 2, and it is possible to appropriately select between the adjacent long steel pipes 2. Further, the distance between the long steel pipe 2 and the hole 15 for detection is preferably about 225 mm if the casting pitch of the long steel pipe 2 is 450 mm, and the casting pitch of the long steel pipe 2 is If it is 600 mm, it is desirable that the position is near the center, that is, about 300 mm from the long steel pipe 2. Further, in the field test, when the casting pitch of the long steel pipe 2 was 900 mm, a detection hole 15 was formed near the center of the long steel pipe 2, that is, at a position 450 mm from the long steel pipe 2, and the detection was performed accurately. It has been confirmed that the filling of the solidifying material could be confirmed by the detection. The detection hole 15 can be formed before the long steel pipe 2 is driven and before the solidifying material is injected, or before the long steel pipe 2 is driven.

Subsequently, as shown in FIG. 10B, the auxiliary long steel pipe 8 is inserted into the detection hole 15 by the drifter 68. At this time, a cone member 83 is attached to the tip of the auxiliary long steel pipe 8. Further, the auxiliary long steel pipe 8 can be inserted into the detection hole 15 at once, or the auxiliary long steel pipe 8 can be inserted into the detection hole 15 while being connected to the steel pipe 81. That is, after inserting one steel pipe 81 with the drifter 68, connecting the other steel pipe 81 to the rear end of the steel pipe 81, the other steel pipe 81 can be inserted into the detection drilling hole 15.

Following this, as shown in FIG. 10C, a plurality of bundled optical fiber sensors 9 are inserted into the auxiliary long steel pipe 8 (three in this embodiment). Then, as shown in FIG. 10 (d), when the tip of the optical fiber sensor 9 reaches the tip of the auxiliary long steel pipe 8, as shown in FIG. 11 (a), the auxiliary long steel pipe 8 is drilled for detection. Pull out from 15. That is, the drifter 68 is attached to the rear end opening of the auxiliary long steel pipe 8 and pulled out from the detection hole 15. At this time, since the rear end opening of the auxiliary long steel pipe 8 is closed by the drifter 68, the optical fiber sensor 9 is pulled out from the slit 82 formed in the rearmost steel pipe 81.

Here, if the auxiliary long steel pipe 8 is pulled out, the optical fiber sensor 9 may be pulled out accordingly. Therefore, the optical fiber sensor 9 pulled out from the slit 82 is pressed toward the inner end of the drilled hole 15. Prevent it from being pulled out together with the auxiliary long steel pipe 8. When the auxiliary long steel pipe 8 is pulled out, the cone member 83 at the tip is separated from the auxiliary long steel pipe 8 and remains in the detection hole 15.

Then, when the rearmost steel pipe 81 is pulled out from the inspection hole 15, it is removed from the auxiliary long steel pipe 8 as shown in FIG. 11B. Following this, the drifter 68 is attached to the steel pipe 81 which is the last one, and the optical fiber sensor 9 is pulled out from the slit 82 of the steel pipe 81. In this way, the auxiliary long steel pipe 8 is pulled out, the optical fiber sensor 9 is pressed, the rearmost steel pipe 81 is removed, and the optical fiber sensor 9 is pulled out from the slit 82, and all the steel pipes 81 are pulled out from the detection holes 15. , As shown in FIG. 11C, the optical fiber sensor 9 remains in the detection hole 15.

In this state, the light emitted from the light emitting unit 921 of the optical fiber sensor 9 is reflected in the detection drilling hole 15 and is received by the light receiving unit 911.

Next, when the solidifying material is injected into the long steel pipe 2, the solidifying material is filled in the long steel pipe 2 and then flows out from the discharge hole 22 and permeates around the long steel pipe 2. To go. At this time, as shown in FIG. 12, the solidifying material also flows into the detection drilling hole 15 formed in the vicinity of the long steel pipe 2 and fills the detection drilling hole 15. In this process, in the optical fiber sensor 9, the light emitted from the light emitting unit 921 is reflected in the detection hole 15 and received in the light receiving unit 911, but the solidifying material flows into the detection hole 15. Therefore, the intensity of the light received by the light receiving unit 911 weakens, and when the detection hole 15 is filled with the solidifying material, the light emitting unit 921 and the light receiving unit 911 are blocked by the solidifying material, so that the light receiving unit 911 The intensity of the light received by is zero. When such a measurement of light intensity is monitored, for example, when the binder is cement-based, it becomes as shown in FIG. 13 (a). FIG. 13A shows the time change of the intensity of the light received by the three optical fiber sensors 9. As shown in the figure, the light intensity of each optical fiber sensor 9 decreases with the passage of time and finally becomes zero.

On the other hand, if the binder flows into the voids and cracks around the long steel pipe 2 and does not flow into the detection drilling hole 15 or sufficiently, the intensity of the light received by the light receiving unit 911 becomes zero. Must not be. Therefore, by observing the measured light intensity, it is possible to confirm whether or not a crack is generated around the long steel pipe 2. At this time, if the tips of the plurality of optical fiber sensors 9 are arranged at different positions in the axial direction of the detection drilling holes 15 as described above, it is considered that cracks are generated along the axial direction. You can check the position.

Further, FIG. 13B is a detection example of the optical fiber sensor 9 when a urethane system is used as the binder. As shown in FIG. 13B, when the urethane-based binder is used, the light intensity may increase with the passage of time after the light intensity received by the optical fiber sensor 9 becomes zero. This is because the urethane-based binder is a foam, so the liquid binder first penetrates into the detection hole 15 to block light, but then foams to allow light to pass through. Is assumed. Alternatively, it is assumed that the liquid urethane adheres to the light emitting portion 921 or the light receiving portion 911 of the optical fiber sensor 9 and the intensity of the received light becomes zero, and then the liquid foams to form a film. To. All of these are phenomena peculiar to the solidifying material such as urethane and silica resin, but if the light intensity changes in this way in the detection drilling hole 15 separated from the long steel pipe 2 by a predetermined distance, the solidifying material is filled. It is confirmed that the situation, that is, the ground improvement situation is sufficient. In addition, since the degree of foaming of the binder can be confirmed by the change in light intensity, reliable work and construction confirmation can be performed.

Then, when the intensity of the light received by the light receiving unit 911 does not become zero and it is considered that a crack is generated around the long steel pipe 2, for example, as shown in FIG. 14, it can be dealt with. it can. In the example of FIG. 14, it is considered that voids and cracks are generated in the region near the tip of the long steel pipe 2 (hereinafter referred to as the fragile region 18), and the filling of the binder is not sufficient. In this case, as shown by the arrow in the figure, the casting position of the long steel pipe 2 is changed so that the pitch is shorter than that of the normal long tip receiving method, and the long steel pipe 2 becomes a fragile area. The long steel pipe 2 is driven so as to pass through 18. Alternatively, an additional binder can be injected with a short injection bolt. In this way, when the vulnerable area 18 is found, it is reinforced and the tunnel is dug.

<3. Features>
As described above, according to the present embodiment, in the detection drilling hole 15, the light emitted from the light emitting unit 921 of the optical fiber sensor 9 is received by the light receiving unit 911, and the intensity of the light received by the light receiving unit is changed. Therefore, it can be confirmed that the binder has penetrated into the ground around the long steel pipe 2. Therefore, it is possible to confirm the state of the ground, that is, the spring water and looseness of the ground around the tunnel and the degree of reinforcement against it without using a large-scale device. In particular, by starting the detection of the light intensity from the stage before the injection, it is possible to confirm in advance that there is spring water in the detection drilling hole 15. Further, since it can be incorporated into the construction of the long tip receiving method, it is possible to prevent the construction time from increasing excessively even though the detection is performed in parallel.

In the above construction method, for example, when there are no cracks in the ground around the long steel pipe 2, the injection amount of the binder to be injected into the long steel pipe 2 and the light receiving portion 911 of the optical fiber sensor 9 The relationship with the intensity of the light received in is measured in advance, and a database can be created as a relationship showing the normal state of the ground. In this way, as compared with the above normal relationship, for example, when the intensity of the received light is low with respect to the injection amount of the binder, there is a possibility that cracks or the like may exist in the ground around the long steel pipe 2. It can be easily determined that there is.

<4. Modification example>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. The following modifications can be combined as appropriate.

<4-1>
An auxiliary long steel pipe is used when inserting the optical fiber sensor into the hole for detection. However, if the optical fiber sensor can be easily inserted, for example, a short hole is always used. There is no need.

<4-2>
In the above embodiment, an optical fiber sensor is used as the detection sensor, but the present invention is not limited to this. That is, it is not particularly limited as long as it is provided with at least a light emitting unit that irradiates light and a light receiving unit that receives the light, and the intensity of the light received by the light receiving unit can be measured.

<4-3>
In the above embodiment, a long steel pipe is used as the long pipe of the present invention, but the configuration thereof is not particularly limited, and is not particularly limited as long as it can reinforce the ground, for example. An FRP pipe, a VP pipe made of hard vinyl chloride, or the like may be used. That is, when constructing the long pipe of the present invention, for example, the material, the length, the number of steel pipes to be connected, the connecting method, and the like can be appropriately changed. Further, the configuration of the drilling bit 3, the bit adapter 41, the drilling rod 61, etc. for drilling is not particularly limited, and the long pipe can be embedded in the ground after drilling. Just do it. This point also applies to the auxiliary long steel pipe.

<4-4>
Further, in the above embodiment, the present invention has been described as an AGF method in which a long pipe is driven along the outer periphery of the ground in front of the face of the tunnel, but the present invention also describes the ground around the tunnel. It can be applied to various auxiliary construction methods such as mirror reinforcement, side pile, and leg pile, in which a long pipe is placed in the tunnel.

1: Face 2: Long steel pipe (long pipe)
9: Optical fiber sensor (detection sensor)
15: Drilling holes for detection 8: Auxiliary long steel pipe (auxiliary long pipe)
81: Steel pipe (pipe member)
82: Slit 911: Light receiving part 921: Light emitting part S: Consolidating material

Claims (9)

A step of preparing a plurality of long tubes having at least one through hole formed on the outer peripheral surface, and
A step of placing the plurality of long pipes in the ground around the tunnel so as to form a predetermined elevation angle with the tunnel axial direction, and
A step of forming at least one detection hole in the vicinity of at least one of the plurality of long pipes in parallel with the long pipe .
A step of inserting at least one detection sensor having a light emitting portion and a light receiving portion into the detection drilling hole,
With the long tube left in the ground , a binder is injected into each of the long tubes, and the solidifying material flowing out from the through hole of the long tube causes the circumference of the long tube to flow. Steps to reinforce the ground and
A step of receiving the light emitted from the light emitting portion of the detection sensor by the light receiving unit and measuring the intensity of the light received by the light receiving unit.
The step of placing concrete on the inner wall surface of the tunnel and
A method for detecting the filling status of a consolidated material . A step of preparing a plurality of long tubes having at least one through hole formed on the outer peripheral surface, and
A step of placing the plurality of long pipes as side piles or leg piles in the radial direction from the inner wall surface of the tunnel in the ground around the tunnel.
A step of forming at least one detection hole in the vicinity of at least one of the plurality of long pipes in parallel with the long pipe.
A step of inserting at least one detection sensor having a light emitting portion and a light receiving portion into the detection drilling hole,
With the long tube left in the ground, a binder is injected into each of the long tubes, and the solidifying material flowing out from the through hole of the long tube causes the circumference of the long tube to flow. Steps to reinforce the ground and
A step of receiving the light emitted from the light emitting portion of the detection sensor by the light receiving unit and measuring the intensity of the light received by the light receiving unit.
The step of placing concrete on the inner wall surface of the tunnel and
A method for detecting the filling status of a consolidated material. A step of preparing a plurality of long tubes having at least one through hole formed on the outer peripheral surface, and
A step of placing the plurality of long pipes as a mirror reinforcement in the direction of the tunnel axis with respect to the mirror surface of the tunnel, and
A step of forming at least one detection hole in the vicinity of at least one of the plurality of long pipes in parallel with the long pipe.
A step of inserting at least one detection sensor having a light emitting portion and a light receiving portion into the detection drilling hole,
With the long tube left in the ground, a binder is injected into each of the long tubes, and the solidifying material flowing out from the through hole of the long tube causes the circumference of the long tube to flow. Steps to reinforce the ground and
A step of receiving the light emitted from the light emitting portion of the detection sensor by the light receiving unit and measuring the intensity of the light received by the light receiving unit.
A method for detecting the filling status of a consolidated material. In the step of measuring the light intensity,
From the relationship between the injection amount of the binder injected into the long tube and the intensity of the light received by the light receiving portion of the detection sensor, the reinforcement status of the ground around the long tube is confirmed. The method for detecting the filling status of a binder according to any one of claims 1 to 3 . Claims that in the step of inserting the detection sensor, a plurality of detection sensors are inserted into the detection holes, and the light emitting portion and the light receiving portion of each detection sensor are arranged at different positions in the hole forming direction. The method for detecting the filling status of a binder according to any one of 1 to 4 . The step of inserting the detection sensor is
The step of inserting an auxiliary long tube into the detection hole and
The step of inserting at least one detection sensor into the auxiliary long tube and
A step of extracting the auxiliary long tube from the detection hole while leaving the detection sensor in the detection hole.
The method for detecting the filling status of the binder according to any one of claims 1 to 5, further comprising . The detection sensor is formed in a long shape having the light emitting portion and the light receiving portion at the tip thereof.
The auxiliary long tube is formed by connecting a plurality of tube members in the axial direction.
The binder according to claim 6 , wherein a slit communicating with the rear end opening of each pipe member is formed on the outer peripheral surface of each pipe member, and the detection sensor can pass through the slit . Filling status detection method. The method for detecting the filling state of a consolidated material according to any one of claims 1 to 7 , wherein the detection sensor is an optical fiber sensor formed in a long shape having the light emitting portion and the light receiving portion at the tip. A solidifying material filling status detection system used in the solidifying material filling status detecting method according to any one of claims 1 to 8.
A plurality of long pipes having at least one through hole formed on the outer peripheral surface, and a plurality of long pipes cast in the ground around the tunnel.
An at least one detection sensor inserted into at least one detection hole formed in the vicinity of at least one of the plurality of long tubes placed in the ground and having a light emitting portion and a light receiving portion.
Equipped with a consolidation material filling status detection system.