Ground mountain reinforcement method

Abstract

To provide a natural ground reinforcing method of high safety and allowing mouth caulking of high work efficiency.SOLUTION: In a natural ground reinforcing method, reinforcing pipes 10 are serially connected to form long reinforcing pipes 20, which are driven into the front natural ground of a cutting face when excavating a tunnel, and consolidation materials 41, 43 are injected to surrounding natural ground of the long reinforcing pipes 20 to reinforce the front natural ground. The method comprises: a first step of driving a terminal reinforcing pipe 10a having circular protrusions 103a capable of closing between an outer peripheral surface and a boring wall 54 at the rear part, at the terminal of the long reinforcing pipe 20; a second step of arranging a packer 33 at a hole deep side position from the circular protrusions 103a inside the terminal reinforcing pipe 10a; a third step of forming a mouth caulking region 42 by injecting the consolidation material 41 into the packer 33 inside and exuding the consolidation material 41 to a mouth side of the boring wall 54 from the packer 33; and a fourth step of injecting the consolidation material 43 to the hole deep side from the packer 33.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a ground reinforcement method in which a long reinforcing pipe is driven into the ground in front of the face during tunnel excavation, and a consolidating material is injected from the long reinforcing pipe into the surrounding ground to reinforce the ground in front.

Background Art

[0002] Conventionally, when performing ground reinforcement, a method is known in which a plurality of steel pipes, which are ground reinforcement pipes, are connected in series and driven into the ground. For example, in the reinforcement in front of the face of a tunnel excavation work, as shown in FIG. 7, a plurality of steel pipes 220 are connected in series and driven into the ground 201 in front of or on the outer periphery of the upper part of the ground 201 to form a long steel pipe 202, and a consolidating material is injected from the driven long steel pipe 202 to form a consolidation region 203, and a long tip-receiving method 204 for improving the ground of the ground 201, or a plurality of steel pipes 220 are connected in series and a long steel pipe 205 is driven from the face into the ground 201 in front, and a long mirror reinforcement method 206 for improving the ground of the ground by injecting a consolidating material from the driven long steel pipe 205 is performed.

[0003] When constructing the long tip-receiving method 204 or the long mirror reinforcement method 206, for example, in the tunnel space T, a steel pipe 220 with a drilling rod 211 inserted therein is mounted on the guide cell 209 of the drilling arm 208 of the drill jumbo 207, and the drilling machine 210 with the drilling rod 211 connected on the guide cell 209 is advanced to drive the steel pipe 220 into the ground 201 while drilling. Then, when the first steel pipe 220 (220a) and the first drilling rod are driven into the ground 201 near the root, an operation of connecting the subsequent second steel pipe 220 (220b) and the second drilling rod is performed. In many cases, steel pipes 220 of about 3 m are connected about 4 times to drive the long steel pipes 202 and 205 (see FIGS. 7 and 8). After driving the long steel pipes 202 and 205, the drilling rod 211 is withdrawn and recovered, an injection pipe is inserted into the long steel pipes 202 and 205, and a consolidating material such as silica resin, urethane, or cement-based material is injected inside and outside the long steel pipes 202 and 205 to perform ground reinforcement.

[0004] In such ground reinforcement construction, since workers have to manually connect steel pipes at high places near the face, in order to reduce the labor required, a method of connecting subsequent steel pipes on the guide cell by simply pushing them in using steel pipes that can be connected by just pushing, as in Patent Documents 1 to 3, has also been considered.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, when driving a long steel pipe into the ground, the reaming bit provided at the tip of the leading steel pipe has a slightly larger diameter than the steel pipe in order to pull the steel pipe in and drive it, so there is a gap between the outer periphery of the steel pipe and the reaming wall. And if the gap at the mouth of the reaming is left as it is, the consolidating material will leak into the tunnel space on the front side of the reaming during the injection operation of the consolidating material from the gap at the mouth, so it is necessary to apply caulking to the mouth.

[0007] In fact, such mouth caulking treatment is carried out by workers climbing to high places for each reaming and manually pushing a wes or a caulking capsule (capsule-type adhesive) into the hole opening, which is a dangerous and time-consuming operation. Therefore, a ground reinforcement method that can perform mouth caulking treatment with high safety and high construction efficiency is desired.

[0008] The present invention is proposed in view of the above problems, and an object thereof is to provide a ground reinforcement method that can perform mouth caulking treatment with high safety and high construction efficiency.

Means for Solving the Problems

[0009] The ground reinforcement method of the present invention is a ground reinforcement method in which reinforcement pipes are connected in series to the ground in front of the face during tunnel excavation to drive a long reinforcement pipe, and a solidifying material is injected into the surrounding ground of the long reinforcement pipe to reinforce the ground in front. The method includes: a first step of driving a terminal reinforcement pipe provided with a circumferential protrusion capable of closing the gap between the outer peripheral surface and the drilled hole wall at the terminal of the long reinforcement pipe; a second step of arranging a packer at a position on the inner side of the terminal reinforcement pipe deeper than the circumferential protrusion; a third step of injecting a solidifying material into the packer and allowing the solidifying material to ooze out from the packer to the mouth side of the drilled hole to form a mouth caulking region; and a fourth step of injecting a solidifying material deeper than the packer from the packer. According to this, the gap between the outer peripheral surface of the terminal reinforcement pipe and the drilled hole wall can be closed by the circumferential protrusion by driving the terminal reinforcement pipe, and the work of workers climbing to a high place and manually stuffing a waste cloth or a caulking capsule into the mouth for each drilled hole can be eliminated. Therefore, it is possible to perform mouth caulking treatment with high safety and high construction efficiency.

[0010] In the first step of the ground reinforcement method of the present invention, with the terminal reinforcement pipe driven halfway, a centralizer provided in the guide cell and supporting the terminal reinforcement pipe is lowered, and the centralizer is moved to the rear side of the circumferential protrusion and raised so as not to interfere with the circumferential protrusion, and the centralizer supports the position of the terminal reinforcement pipe behind the circumferential protrusion, and the driving work of the terminal reinforcement pipe is restarted. According to this, interference between the circumferential protrusion of the terminal reinforcement pipe and the centralizer, and damage to the circumferential protrusion or the centralizer due to the interference can be prevented. Also, centering of the terminal reinforcement pipe by the centralizer can be ensured.

[0011] The ground reinforcement method of the present invention is characterized in that a plurality of the circumferential protrusions of the terminal reinforcement pipe are provided at intervals in the axial direction. According to this, the gap between the outer peripheral surface of the terminal reinforcement pipe and the bored wall can be made more surely in a closed state by the partition wall formed by a plurality of circumferential protrusions arranged at intervals in the axial direction. Since the plurality of circumferential protrusions are provided at intervals in the axial direction, when the consolidating material gets into the space between the circumferential protrusions, it is firmly and limitedly injected there, and the mouth edge caulking is surely performed.

[0012] The ground reinforcement method of the present invention is characterized in that the circumferential protrusion of the terminal reinforcement pipe is formed in a tapered shape whose diameter gradually increases toward the rear end. According to this, the circumferential protrusion can be smoothly inserted into the bored hole, and the gap between the outer peripheral surface of the terminal reinforcement pipe and the bored wall can be surely made in a closed state.

Effects of the Invention

[0013] According to the ground reinforcement method of the present invention, it is possible to perform a mouth edge caulking process with high safety and high construction efficiency.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

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Figure 4

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Figure 7

Figure 8

Embodiment for Carrying Out the Invention

[0015] 〔Ground Reinforcement Method of the Embodiment〕 The ground reinforcement method of the embodiment according to the present invention is a ground reinforcement method in which reinforcement pipes 10 and 10a are connected in series to the ground in front of the face during tunnel excavation to drive a long reinforcement pipe 20, and a solidifying material is injected into the ground around the long reinforcement pipe 20 to reinforce the ground in front. During the construction, for example, as shown in Fig. 1(a), the reinforcement pipe 10, which is a ground reinforcement pipe, is driven into the ground 51 from the face of the ground 51 provided with shotcrete 52. The reinforcement pipe 10, which is a ground reinforcement pipe, is preferably made of a steel pipe, but it is also possible to use a reinforcement pipe made of other materials such as resin.

[0016] For driving the reinforcement pipe 10, for example, a drilling device having a guide cell 11 attached to the arm of a drill jumbo and a boring machine 12 mounted on the guide cell 11 so as to be movable forward and backward is used (see Fig. 1). A centralizer for supporting the reinforcement pipe 10 attached to the boring machine 12 from below is provided on the guide cell 11. In the illustrated example, a fixed centralizer 13 is fixed at the leading position of the guide cell 11, and a movable centralizer 14 is provided so as to move forward and backward in a predetermined area on the guide cell 11.

[0017] A boring rod is inserted into the inside of the reinforcing pipe 10 (not shown in the figure). At the leading reinforcing pipe 10, a boring bit at the leading end of the boring rod is engaged via a casing shoe at the tip of the leading reinforcing pipe 10. This engagement is configured to engage by the forward rotation of the boring machine 12 and disengage by the reverse rotation. That is, when the reinforcing pipe 10 already driven into the ground 51 is the leading pipe, the boring bit is engaged at the tip of the reinforcing pipe 10 of the leading pipe, and the boring rod is inserted into the reinforcing pipe 10. Fig. 1(a) shows a state where a plurality of reinforcing pipes 10 composed of a leading pipe and intermediate pipes are already connected and driven into the ground 51, and the terminal portion of the reinforcing pipe 10 of the intermediate pipe protrudes from the boring 53 to the outside of the ground 51.

[0018] Further, the reinforcing pipe 10 has a structure in which the subsequent reinforcing pipe 10 is pushed into and connected to the preceding reinforcing pipe 10. This reinforcing pipe 10 is configured, for example, by externally fitting an engaging member formed in a substantially C shape on the outer periphery of the rear end portion, and forming an engaging groove into which the engaging member is fitted from the inside on the inner periphery of the tip portion. Then, the tip portion of the subsequent reinforcing pipe 10 is pushed into the outside of the rear end portion of the preceding reinforcing pipe 10 so as to be fitted, the engaging member is slightly reduced in diameter, and the engaging member is elastically restored to the original diameter at the groove position of the subsequent reinforcing pipe 10 and fitted into the engaging groove, thereby connecting the preceding reinforcing pipe 10 and the subsequent reinforcing pipe 10.

[0019] In Figs. 1(a) and 1(b), a terminal reinforcing pipe 10a having the same structure of being pushed in and connected as that of the reinforcing pipe 10 is centered and brought closer to the reinforcing pipe 10 of the preceding intermediate pipe already driven into the ground 51 by a fixed centering device 13 and a movable centering device 14, and the subsequent terminal reinforcing pipe 10a is pushed into and connected to the reinforcing pipe 10 of the intermediate pipe. The terminal reinforcing pipe 10a connected to the intermediate pipe is driven into the deeper side of the ground 51 by the boring of the boring bit together with the reinforcing pipe 10 of the leading pipe and the reinforcing pipe 10 of the intermediate pipe.

[0020] Similar to the reinforcing pipes 10 of the leading pipe and the intermediate pipes, the terminal reinforcing pipe 10a has discharge holes 102a for the solidifying material formed in the peripheral wall 101a, and a circumferential protrusion 103a capable of closing the space between the outer peripheral surface of the peripheral wall 101a and the boring wall 54 of the boring 53 is provided at the rear portion (see Figs. 1 to 4).

[0021] The circumferential protrusions 103a in FIGS. 1 to 4 are formed by ridges protruding in a flange shape from the circumferential wall 101a, and a plurality of them are provided at intervals in the axial direction. In the illustrated example, three circumferential protrusions 103a are provided at intervals from each other. The circumferential protrusions 103a of these ridges are provided, for example, by welding or the like to the circumferential wall 101a. Further, it is preferable that the tip of the circumferential protrusion 103a on the hole bottom side is provided at a distance of about 80 cm from the rear end of the terminal reinforcing pipe 10a. Since the terminal reinforcing pipe 10a is placed in a state where it protrudes about 15 to 30 cm outward from the sprayed concrete 52 when the placement is completed, it is preferable to provide a plurality of circumferential protrusions 103a, such as three, in the range of about 40 to 80 cm from the rear end of the terminal reinforcing pipe 10a.

[0022] When the placement of the terminal reinforcing pipe 10a progresses and the circumferential protrusion 103a of the terminal reinforcing pipe 10a reaches near the centralizer, with the terminal reinforcing pipe 10a placed halfway, the centralizer supporting the terminal reinforcing pipe 10a, in this example, the fixed centralizer 13 and the movable centralizer 14 are lowered, and the centralizer is moved to the rear side of the circumferential protrusion 103a and raised so as not to interfere with the circumferential protrusion 103a, and the centralizer supports the position behind the circumferential protrusion 103a of the terminal reinforcing pipe 10a, and the placement work of the terminal reinforcing pipe 10a is resumed (see FIGS. 1(c) to (e)).

[0023] In the examples of FIGS. 1(c) to 1(e), the guide cell 11 provided with a centering device composed of a fixed centering device 13 and a movable centering device 14 is lowered, the guide cell 11 is moved and raised so that the centering device is disposed on the rear side of the circumferential protrusion 103a, and the guide cell 11 is raised so that the centering device supports a position on the rear side of the circumferential protrusion 103a of the terminal reinforcing pipe 10a. In FIG. 1(d), for the sake of illustration, a state in which the guide cell 11 is sufficiently lowered is shown. However, when performing this step in actual construction, since there is a drilling rod inserted into the terminal reinforcing pipe 10a, it is sufficient to lower the guide cell 11 only slightly so that the circumferential protrusion 103a can pass through. If this is difficult, the drilling rod can be removed from the drilling machine 12 on the guide cell 11, and after arranging the centering device to support a position on the rear side of the circumferential protrusion 103a of the terminal reinforcing pipe 10a, the drilling rod can be attached to the drilling machine 12 again. Further, the centering devices 13 and 14 may be configured to descend with respect to the guide cell 11. Furthermore, for example, by devising the shape such that the circumferential protrusion 103a and the centering devices 13 and 14 can pass through without much interference, such as making the front surface of the circumferential protrusion 103a an inclined surface inclined forward, it is also possible to pass the centering devices 13 and 14 through without accompanying the descending and ascending steps.

[0024] After resuming the placing operation of the terminal reinforcing pipe 10a, the circumferential protrusion 103a of the terminal reinforcing pipe 10a enters the drilled hole 53, and the terminal reinforcing pipe 10a is placed up to a predetermined position where the circumferential protrusion 103a is arranged so as to close the space between the outer peripheral surface of the peripheral wall 101a and the drilled hole wall 54, thereby completing the placing operation of the terminal reinforcing pipe 10a. The placed terminal reinforcing pipe 10a constitutes the terminal of the long reinforcing pipe 20 (see FIG. 2(a)). Incidentally, the drilling rod inserted into the terminal reinforcing pipe 10a, the leading pipe, and the reinforcing pipes 10 of the intermediate pipes is withdrawn and recovered.

[0025] An injection device 30 for the consolidation material is attached to the installed terminal reinforcement pipe 10a (see Figs. 2(b) and (c)). The injection device 30 includes a terminal cap 31 that is detachably externally fitted and attached to the rear end of the terminal reinforcement pipe 10a, a packer injection hose 32 that is provided so as to penetrate the substrate 311 of the terminal cap 31 and is inserted into the terminal reinforcement pipe 10a, a packer 33 that is provided at the tip of the packer injection hose 32 and is disposed inside the terminal reinforcement pipe 10a, and a backside injection hose 34 that is provided so as to penetrate the substrate 311 of the terminal cap 31 and is inserted into the long reinforcement pipe 20. In the drawings, for the sake of simplicity, only one backside injection hose 34 is shown, but in actual construction, a plurality of backside injection hoses 34 having different lengths are used according to the length of the long reinforcement pipe 20, and they are often arranged so that stepwise injection can be performed for each injection area in the injection process on the backside of the packer 33.

[0026] Then, as shown in Figs. 2(c) and 4(a), the packer 33 is disposed at a position on the hole inner side of the circumferential protrusion 103a inside the terminal reinforcement pipe 10a, and preferably is spaced apart from the hole inner side tip of the circumferential protrusion 103a in the axial direction of the terminal reinforcement pipe 10a. For example, when three circumferential protrusions 103a are arranged in the range of 40 to 80 cm from the rear end of the terminal reinforcement pipe 10a, the packer 33 is arranged at a position about 1 m on the hole inner side from the rear end of the terminal reinforcement pipe 10a.

[0027] In this state, the consolidation material 41 is injected into the packer 33, and the consolidation material 41 is leached from the packer 33 to the mouth side of the drilled hole 53 to form a mouth coking region 42 (see Figs. 2(c), (d), and 4(b)). It is preferable to use a packer 33 in which the consolidation material 41 can only ooze out to the mouth side. For example, a packer 33 formed of a material such as nylon, vinyl, or rubber that does not allow the consolidation material 41 to ooze out on the hole inner side and a material such as cloth that allows the consolidation material 41 to ooze out on the mouth side is good.

[0028] In the peripheral wall 101a of the terminal reinforcing pipe 10a between the packer 33 disposed inside the terminal reinforcing pipe 10a and the tip on the hole bottom side of the plurality of circumferential protrusions 103a, a discharge hole 102a for the consolidation material is formed. Then, when the consolidation material 41 is injected into the packer 33, after the packer 33 swells due to the filling of the consolidation material 41, the consolidation material 41 oozing out from the packer 33 is injected into the inside of the terminal reinforcing pipe 10a on the mouth side of the drilled hole 53, and at the same time, it is discharged to the outside of the terminal reinforcing pipe 10a from the discharge hole 102a of the peripheral wall 101a between the packer 33 and the tip on the hole bottom side of the circumferential protrusion 103a and injected into the drilled hole 53 and the natural ground 51, and the mouth calking region 42 is formed.

[0029] After the formation of the mouth calking region 42, the consolidation material 43 is injected from the inner injection hose 34 inserted inside the long reinforcing pipe 20. The consolidation material 43 is injected into the inside of the long reinforcing pipe 20 on the hole bottom side from the mouth calking region 42, and at the same time, it is discharged to the outside of the long reinforcing pipe 20 from the discharge hole 102a of the terminal reinforcing pipe 10a and the discharge holes formed in the reinforcing pipes 10 of the intermediate pipe and the head pipe constituting the long reinforcing pipe 20 and injected into the drilled hole 53 and the natural ground 51, and the consolidation region 44 is formed in a state where the leakage of the consolidation material 43 is prevented in the mouth calking region 42 (see Fig. 2(e)).

[0030] According to the ground reinforcement method of the present embodiment, the gap between the outer peripheral surface of the terminal reinforcing pipe 10a and the drilled hole wall 54 can be closed by the circumferential protrusion 103a when the terminal reinforcing pipe 10a is driven, and the operation of the worker climbing to a high place for each drilled hole and manually stuffing a waste cloth or a calking capsule into the mouth can be eliminated. Therefore, a mouth calking process with high safety and high construction efficiency can be performed.

[0031] In addition, the gap between the outer peripheral surface of the terminal reinforcing pipe 10a and the drilled hole wall 54 can be more reliably closed by a partition formed by a plurality of circumferential protrusions 103a arranged at intervals in the axial direction of the terminal reinforcing pipe 10a. Since the plurality of circumferential protrusions 103a are provided at intervals in the axial direction, when the consolidating material gets into the space between the circumferential protrusions 103a and the circumferential protrusions, it is firmly and limitedly injected there, and the mouth calking is surely performed. Incidentally, when there is only one circumferential protrusion 103a, by injecting an excessive amount of the consolidating material 41 into the packer 33, the mouth calking can be surely performed.

[0032] Further, by a process of lowering, moving backward and then raising the centering device, supporting a position behind the circumferential protrusion 103a of the terminal reinforcing pipe 10a with the centering device, and resuming the placing operation of the terminal reinforcing pipe 10a, interference between the circumferential protrusion 103a of the terminal reinforcing pipe 10a and the centering device, and damage to the circumferential protrusion 103a or the centering device due to the interference can be prevented. Also, centering of the terminal reinforcing pipe 10a by the centering device can be ensured.

[0033] 〔Scope of the Invention Disclosed in this Specification〕 The invention disclosed in this specification includes, in addition to each invention, embodiment, and each example listed as the invention, within the applicable range, those obtained by changing some of these partial contents to other contents disclosed in this specification, or those obtained by adding other contents disclosed in this specification to these contents, or those obtained by deleting some of these partial contents to the extent that partial operational effects can be obtained and generalizing them to a higher concept. And the invention disclosed in this specification also includes the following contents and the following further modified examples.

[0034] For example, the configuration of the terminal reinforcement pipe used in the ground reinforcement method of the present invention is not limited to the terminal reinforcement pipe 10a of the above embodiment and can be appropriately selected within the scope of the gist of the present invention. For example, it is also suitable to use the terminal reinforcement pipe 10b shown in FIGS. 5 and 6. The terminal reinforcement pipe 10b has the same structure of being pushed in and connected as the reinforcement pipe 10 and the terminal reinforcement pipe 10a. Discharge holes 102b for the solidifying material are formed in the peripheral wall 101b, and a circumferential protrusion 103b capable of closing the space between the outer peripheral surface of the peripheral wall 101b and the drilled wall 54 of the drilled hole 53 is provided at the rear.

[0035] The circumferential protrusion 103b of the terminal reinforcement pipe 10b is formed in a tapered shape with a gradually increasing diameter toward the rear end. In the illustrated example, it is a tapered rubber cylinder with an outer peripheral surface gradually increasing in diameter toward the rear end. An annular plate 104b protruding outward in a flange shape is formed on the peripheral wall 101b near the rear end of the terminal reinforcement pipe 10b and is fixed to the peripheral wall 101b by welding or the like. The circumferential protrusion 103b composed of the tapered rubber cylinder in this example is fitted outside the peripheral wall 101b so as to abut against the front end surface of the annular plate 104b that positions its rear end surface.

[0036] It is preferable that the tip of the tapered circumferential protrusion 103b of the terminal reinforcement pipe 10b on the hole depth side is provided at a distance of about 80 cm from the rear end of the terminal reinforcement pipe 10b. Further, it is desirable that the tip of the tapered circumferential protrusion 103b is at a position about 50 cm from the annular plate 104b. In addition, when the placement of the terminal reinforcement pipe 10b is completed with it protruding about 15 - 30 cm outward from the sprayed concrete 52, and the rear end surface of the circumferential protrusion 103b and the annular plate 104b are arranged outside the sprayed concrete 52 in the placement-completed state, it is preferable that the rear end surface of the tapered circumferential protrusion 103b is arranged at a position about 2 - 20 cm from the rear end of the terminal reinforcement pipe 10b.

[0037] Even in the placement work of the terminal reinforcing pipe 10b, similar to the above-described terminal reinforcing pipe 10a, when the circumferential protrusion 103b of the terminal reinforcing pipe 10b reaches near the centralizer, with the terminal reinforcing pipe 10b placed halfway, lower the centralizer that supports the terminal reinforcing pipe 10b, and move and raise the centralizer to the rear side of the circumferential protrusion 103b and the annular plate 104b so as not to interfere with the circumferential protrusion 103b and the annular plate 104b, support the position behind the circumferential protrusion 103b and the annular plate 104b of the terminal reinforcing pipe 10b with the centralizer, and resume the placement work of the terminal reinforcing pipe 10b.

[0038] After resuming the placement work of the terminal reinforcing pipe 10b, close the space between the outer peripheral surface of the peripheral wall 101b and the reamed hole wall 54 by pressing the tapered surface of the circumferential protrusion 103b of the terminal reinforcing pipe 10b against the reamed hole wall 54, and place the terminal reinforcing pipe 10b to the predetermined position, thereby completing the placement work of the terminal reinforcing pipe 10b that constitutes the terminal of the long reinforcing pipe 20.

[0039] Attach the above-described consolidation material injection device 30 to the placed terminal reinforcing pipe 10b, and arrange the packer 33 at a position on the hole bottom side from the circumferential protrusion 103b inside the terminal reinforcing pipe 10b, preferably spaced apart from the hole bottom side tip of the circumferential protrusion 103b in the axial direction of the terminal reinforcing pipe 10b. In this state, inject the consolidation material 41 into the packer 33, and let the consolidation material 41 ooze out from the packer 33 to the mouth side of the reamed hole 53 to form the mouth caulking region 42.

[0040] Discharge holes 102b for the consolidation material are formed in the peripheral wall 101b of the terminal reinforcing pipe 10b between the packer 33 arranged inside the terminal reinforcing pipe 10b and the tip on the hole bottom side of the tapered circumferential protrusion 103b. When the consolidation material 41 is injected into the packer 33, after the packer 33 swells due to the filling of the consolidation material 41, the consolidation material 41 oozing out from the packer 33 is injected into the inside of the terminal reinforcing pipe 10b on the mouth side of the reamed hole 53, and is discharged to the outside of the terminal reinforcing pipe 10b from the discharge holes 102b of the peripheral wall 101b between the packer 33 and the tip on the hole bottom side of the circumferential protrusion 103b, and is injected into the reamed hole 53 and the natural ground 51, and the mouth caulking region 42 is formed.

[0041] After the formation of the mouth edge caulking region 42, in the same manner as when using the terminal reinforcing pipe 10a, the solidifying material 43 is sequentially injected from the required number of backside injection hoses 34 inserted inside the long reinforcing pipe 20, and the solidifying region 44 is formed in a state where leakage of the solidifying material 43 is prevented in the mouth edge caulking region 42.

[0042] According to the ground reinforcement method using the terminal reinforcing pipe 10b, corresponding effects can be obtained from the configuration corresponding to the ground reinforcement method using the terminal reinforcing pipe 10a, and the tapered circumferential protrusion 103b can be smoothly inserted into the drilled hole 53 to surely close the gap between the outer peripheral surface of the terminal reinforcing pipe 10b and the drilled hole wall 54.

Industrial Applicability

[0043] The present invention can be used when driving a long steel pipe into the ground in front of the face during tunnel excavation and injecting a solidifying material from the long steel pipe into the surrounding ground to reinforce the ground in front.

Explanation of Signs

[0044] 10... Reinforcing pipe 11... Guide cell 12... Drilling machine 13... Fixed centralizer 14... Movable centralizer 10a... Terminal reinforcing pipe 101a... Peripheral wall 102a... Discharge hole 103a... Circumferential protrusion 10b... Terminal reinforcing pipe 101b... Peripheral wall 102b... Discharge hole 103b... Circumferential protrusion 104b... Annular plate 20... Long reinforcing pipe 30... Injecting device 31... Terminal cap 311... Substrate 32... Packer injection hose 33... Packer 34... Backside injection hose 41... Solidifying material 42... Mouth edge caulking region 43... Solidifying material 44... Solidifying region 51... Ground 52... Sprayed concrete 53... Drilled hole 54... Drilled hole wall 201... Ground 202... Long steel pipe 203... Solidifying region 204... Long tip receiving work 205... Long steel pipe 206... Long mirror reinforcement work 207... Drill jumbo 208... Drilling arm 209... Guide cell 210... Drilling machine 211... Drilling rod 220, 220a, 220b... Steel pipe T... Tunnel space

Claims

1. A ground reinforcement method for tunneling, in which reinforcing pipes are connected in series to the ground in front of the face to drive a long reinforcing pipe, and a consolidating material is injected into the ground around the long reinforcing pipe to reinforce the ground in front, comprising: a first step of driving a terminal reinforcing pipe provided with a circumferential protrusion at the rear that can close the space between the outer peripheral surface and the bored hole wall at the terminal of the long reinforcing pipe; a second step of arranging a packer at a position on the hole bottom side of the circumferential protrusion inside the terminal reinforcing pipe; a third step of injecting a consolidating material into the packer and allowing the consolidating material to ooze out from the packer to the mouth side of the bored hole to form a mouth caulking region; a fourth step of injecting a consolidating material to the hole bottom side of the packer, and in the first step, with the terminal reinforcing pipe driven halfway, a centralizer provided in the guide cell and supporting the terminal reinforcing pipe is lowered, moved to the rear side of the circumferential protrusion so as not to interfere with the circumferential protrusion, and then raised, and the centralizer supports the position on the rear side of the circumferential protrusion of the terminal reinforcing pipe, and the driving operation of the terminal reinforcing pipe is resumed. The ground reinforcement method is characterized by this.

2. A ground reinforcement method for tunneling, in which reinforcing pipes are connected in series to the ground in front of the face to drive a long reinforcing pipe, and a consolidating material is injected into the ground around the long reinforcing pipe to reinforce the ground in front, comprising: a first step of driving a terminal reinforcing pipe provided with a circumferential protrusion at the rear that can close the space between the outer peripheral surface and the bored hole wall at the terminal of the long reinforcing pipe; a second step of arranging a packer at a position on the hole bottom side of the circumferential protrusion inside the terminal reinforcing pipe; a third step of injecting a consolidating material into the packer and allowing the consolidating material to ooze out from the packer to the mouth side of the bored hole to form a mouth caulking region; a fourth step of injecting a consolidating material to the hole bottom side of the packer, and the ground reinforcement method is characterized in that a plurality of the circumferential protrusions of the terminal reinforcing pipe are provided at intervals in the axial direction.

3. A ground reinforcement method for tunneling, in which reinforcing pipes are connected in series to the ground in front of the face to drive a long reinforcing pipe, and a consolidating material is injected into the ground around the long reinforcing pipe to reinforce the ground in front, comprising: a first step of driving a terminal reinforcing pipe provided with a circumferential protrusion at the rear that can close the space between the outer peripheral surface and the bored hole wall at the terminal of the long reinforcing pipe; a second step of arranging a packer at a position on the hole bottom side of the circumferential protrusion inside the terminal reinforcing pipe; A third step of injecting a consolidating material into the packer and allowing the consolidating material to leach out from the packer to the mouth side of the drilled hole to form a mouth calking region; A fourth step of injecting a consolidating material to the back side of the hole from the packer; and A ground reinforcement method characterized in that the circumferential protrusion of the terminal reinforcement pipe is formed in a tapered shape in which the diameter gradually increases toward the rear end.

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