Long length pre-support construction method

Abstract

To provide a ground reinforcement pipe, which can eliminate the need for a cutting-off operation on a terminal-part partial pipe during the excavation of a tunnel that uses a non-widening long forepoling construction method, and can eliminate industrial waste during using the ground reinforcement pipe.SOLUTION: A ground reinforcement pipe 1 allows a drilling rod 11 to be inserted therein, the drilling rod being used in a non-widening long forepoling construction method. The ground reinforcement pipe has a head-part partial pipe 2 with a tip being fitted with a drill bit 12. The ground reinforcement pipe is provided with a terminal-part partial pipe 5 and a storage partial pipe 4 inserted with the terminal-part partial pipe 5 by a telescopic mechanism, wherein the terminal-part partial pipe 5 is telescopically inserted in the storage partial pipe 4.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention provides Use ground reinforcement pipes Regarding the long-length pre-support construction method. [Background technology]

[0002] As shown in Figure 7, the long fore-affected ground reinforcement method (AGF method) involves casting three or four connected partial steel pipes 203 of about 3 m each diagonally forward from the ground 202 closest to the tunnel face 201 to form a long ground reinforcement pipe 204, and then infiltrating a consolidation material 205 into the ground 202 around the ground reinforcement pipe 204 to form a consolidated area, thereby covering and reinforcing the ground 202 around the tunnel space T to be excavated like an umbrella. When using the long fore-affected ground reinforcement method, normally, during tunnel excavation, shoring 206 is erected and shotcrete 207 is applied every 1 m or so of excavation, and long ground reinforcement pipes 204 are cast every 10 m or so of excavation.

[0003] When the long forepiling method is performed without widening, a long natural ground reinforcement pipe 204 is cast diagonally forward from the natural ground 202 closest to the tunnel face 201, and the terminal steel pipe 203a that constitutes the natural ground reinforcement pipe 204 and the consolidated region made of the consolidated material 205 around it are placed in the natural ground 202 to be excavated in the next and next excavation cycles. These terminal steel pipes 203a generally have slits or annular grooves formed in them, and the terminal steel pipes 203a and the consolidated region made of the consolidated material 205 that get in the way as the tunnel is excavated are removed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3882118 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in the long-length pre-supporting method, the end steel pipe 203a is excavated during tunnel excavation using a backhoe or the like, and vibrations generated during the excavation are transmitted from the steel pipe 203 located forward of the end steel pipe 203a to the natural ground 202 ahead. The transmission of vibrations to the natural ground 202 due to this excavation work is one of the causes of loosening the natural ground 202.

[0006] Furthermore, since the cut end steel pipe 203a is often integrated with the consolidating material 205, it is difficult to recycle and there is also the problem that it becomes industrial waste.

[0007] The present invention has been proposed in view of the above-mentioned problems, and is a ground reinforcement method that can eliminate the need to cut off end pipes when excavating a tunnel using a long-length pre-supporting method without widening, and can also eliminate industrial waste when using ground reinforcement pipes. Tube The purpose is to provide a long-length pre-support construction method. [Means for solving the problem]

[0008] The present invention Used in long-length pre-support construction method The ground reinforcement pipe is a ground reinforcement pipe into which a drilling rod used in a long-length pre-receiving method without widening can be freely inserted, and is characterized in that it has a front section pipe to which a drilling bit is attached at the tip, and a terminal section pipe and a storage section pipe into which the terminal section pipe is inserted using a telescopic mechanism are provided at the rear, and the terminal section pipe is provided so as to be freely extendable and contractible relative to the storage section pipe. According to this, by providing the end partial pipe with a telescopic mechanism that allows it to be freely extended and retracted relative to the encased partial pipe, the exposed end partial pipe can be housed in the encased partial pipe during tunnel excavation, thereby eliminating the need to cut off the end partial pipe when excavating a tunnel using a long-length fore-receiving method without widening the tunnel. Furthermore, since the work of connecting the encased partial pipe and the end partial pipe using a screw connection or the like is no longer necessary, the labor required for connecting the partial pipes that make up the long ground reinforcement pipe can be reduced. Furthermore, since no cut-off end partial pipes are generated when tunnel excavation is performed using the ground reinforcement pipe, industrial waste generated when the ground reinforcement pipe is used can be eliminated, and the need for sorting industrial waste can also be eliminated. Furthermore, since the work of cutting off the end partial pipes can be eliminated, the situation in which the ground becomes loose due to vibrations caused by the work of cutting off the end partial pipes can be prevented.

[0009] The present invention Used in long-length pre-support construction method The natural ground reinforcing pipe is characterized in that no discharge holes for the consolidation material are formed on the peripheral wall of the terminal pipe section and the peripheral wall of the accommodation pipe section. This means that it is not necessary to form discharge holes for the consolidation material in the terminal partial pipes that are expected to be housed in the housing partial pipe during tunnel excavation work, or in the housing partial pipes that are expected to house the terminal partial pipes, eliminating the need to process discharge holes in the partial pipes located at the rear and reducing manufacturing costs.In addition, even without injecting and filling the terminal partial pipes and housing partial pipes with consolidation material, the state in which the terminal partial pipe is housed in the housing partial pipe forms a double pipe, ensuring sufficient rigidity for the ground reinforcement pipe where the housing partial pipe is installed.

[0010] The long length fore-receiving method of the present invention is a long length fore-receiving method using the natural ground reinforcement pipe of the present invention, and includes a first step of pulling the leading portion of the pipe by drilling a hole with a drill bit attached to the tip, thereby pulling out the terminal portion of the pipe from the containing portion of the pipe and driving the natural ground reinforcement pipe into the natural ground; Insidea second step of placing a packer in the tunnel, injecting a consolidating material in front of the expanded packer, and discharging the consolidating material into the surrounding ground from a discharge hole formed in the ground reinforcement pipe forward of the accommodating partial pipe; and a third step of returning the terminal partial pipe exposed in the ground to be excavated into the accommodating partial pipe as the tunnel is excavated. This allows the long ground reinforcement pipe to be installed in the ground by pulling the end pipe out of the encasing pipe. This eliminates the need for connecting the encasing pipe and the end pipe, such as by screwing them together, thereby reducing the labor required for connecting the end pipes. Since the consolidation material only needs to be injected forward of the packer located near the tip of the encasing pipe, the amount of consolidation material injected can be reduced, thereby lowering construction costs. Furthermore, the exposed end pipe can be housed in the encasing pipe during tunnel excavation, eliminating the need to cut off the end pipe when using a long-length fore-supporting method without widening the tunnel. Furthermore, since no cut-off end pipe is generated during tunnel excavation using the ground reinforcement pipe, industrial waste is eliminated and the need for separate disposal of industrial waste is eliminated. Furthermore, eliminating the need to cut off the end pipe can prevent loosening of the ground due to vibrations caused by the cutting off of the end pipe. [Effects of the Invention]

[0011] According to the present invention, it is possible to eliminate the need to cut off end pipes when excavating tunnels using a long-length pre-receiving method without widening, and it is also possible to eliminate industrial waste when using ground reinforcement pipes. [Brief explanation of the drawings]

[0012] [Figure 1] 1A is an exploded perspective view of a ground reinforcement pipe and a drill bit according to an embodiment of the present invention, and FIG. 1B is a perspective view of the ground reinforcement pipe according to the embodiment with a drill bit attached to the leading pipe portion. [Figure 2] (a) is a front view of an embodiment of a ground reinforcement pipe and a drill bit in a pouring state, and (b) is a schematic end view showing the connection structure of the ground reinforcement pipe in (a). [Figure 3] 1A is a cross-sectional view showing a housing portion pipe and a terminal portion pipe in a ground reinforcement pipe according to an embodiment, and FIG. 1B is a cross-sectional explanatory view illustrating the fitting connection between the housing portion pipe and the terminal portion pipe. [Figure 4] 10A and 10B are process explanatory diagrams illustrating the first half of the process of placing a ground reinforcement pipe according to an embodiment. [Figure 5] 10A and 10B are process explanatory diagrams illustrating the latter half of the process of placing a ground reinforcement pipe according to an embodiment. [Figure 6] 10(a) to 10(e) are process diagrams illustrating the injection of consolidation material into the natural ground reinforcement pipe of the cast embodiment and the insertion of the terminal pipe into the receiving pipe. [Figure 7] FIG. 1 is an explanatory diagram illustrating a conventional long-length pre-support construction method. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Embodiment of ground reinforcement pipe and long-length pre-receiving method] The ground reinforcement pipe 1 of an embodiment according to the present invention is a ground reinforcement pipe 1 into which a drilling rod 11 used in a long-length pre-receiving method without widening can be freely inserted, and as shown in Figures 1 to 3, is composed of a front section pipe 2 having a drilling bit 12 attached to its tip, an intermediate section pipe 3 connected to the rear side of the front section pipe 2, a storage section pipe 4 connected to the rear side of the intermediate section pipe 3, and a terminal section pipe 5 inserted into the storage section pipe 4 using a telescopic mechanism, and the storage section pipe 4 and the terminal section pipe 5 are provided at the rear of the ground reinforcement pipe 1.

[0014] The leading pipe section 2 is formed in a substantially cylindrical shape and has a base section 21 formed with a substantially uniform outer diameter, a female thread section 22 formed on the inside of the tip section of the base section 21, and a male thread section 23 formed on the reduced diameter section at the rear of the base section 21. The base section 21 is formed with a discharge hole 24 that is a through hole that discharges a consolidation material into the ground surrounding the leading pipe section 2, and a drill bit 12 is attached to the tip of the base section 21 via a casing shoe 13.

[0015] The intermediate pipe section 3 is formed in a substantially cylindrical shape and has a base section 31 formed with a substantially uniform outer diameter, a female thread section 32 formed inside the tip of the base section 31, and a male thread section 33 formed in the reduced diameter section at the rear of the base section 31. The base section 31 is formed with a discharge hole 34, which is a through hole that discharges a consolidation material into the ground surrounding the intermediate pipe section 3. The female thread section 32 of the intermediate pipe section 3 is threadedly engaged with the male thread section 23 of the leading pipe section 2, and the intermediate pipe section 3 and the leading pipe section 2 are threadedly connected by a threaded connection. It is also possible to use an intermediate pipe section 3 with the same shape and size as the leading pipe section 2. The leading pipe section 2 and the intermediate pipe section 3 can be made of steel pipes or plastic pipes, but steel pipes are preferable from the standpoint of strength.

[0016] The encasing pipe section 4 is generally cylindrical and includes a base section 41 with generally uniform outer and inner diameters, an internal thread 42 formed inside the tip of the base section 41, a tapered section 43 whose diameter gradually decreases from the rear end of the base section 41 toward the rear, and a tapered section 44 extending rearward from the rear end of the tapered section 43 and with generally uniform outer and inner diameters. The internal thread 42 of the encasing pipe section 4 is threadedly engaged with the external thread 33 of the intermediate pipe section 3, thereby connecting the encasing pipe section 4 and the intermediate pipe section 3. The base section 41, which forms the peripheral wall of the encasing pipe section 4, does not have a through-hole for discharging the cement into the surrounding ground. The encasing pipe section 4 can be made of either a steel pipe or a plastic pipe, but a steel pipe is preferred from the standpoint of strength. The dimensions of the encasing pipe section 4 can be adjusted as needed.

[0017] The terminal pipe section 5 is formed in a substantially cylindrical shape and has a base section 51 formed with substantially the same outer and inner diameters, a tapered section 52 whose diameter gradually increases from the front end of the base section 51 toward the front, an expanded diameter cylindrical section 53 extending forward from the front end of the tapered section 52 and having substantially the same outer and inner diameters, and a flange 54 provided at the rear end of the expanded diameter cylindrical section 53. The base section 51, which forms the peripheral wall of the terminal pipe section 5, does not have a discharge hole formed therein for discharging a consolidation material into the surrounding ground. The terminal pipe section 5 can be made of either a steel pipe or a plastic pipe, but a steel pipe is preferable from the viewpoint of strength. The dimensions of the terminal pipe section 5 can be appropriately set as needed to match the dimensions of the housing pipe section 4.

[0018] The terminal partial pipe 5 is inserted into the accommodating partial pipe 4 by a telescopic mechanism, and the enlarged diameter cylindrical portion 53, the tapered portion 52, and a part of the base portion 51 behind the tapered portion 52 form a fitting portion that fits into a fitting portion formed by a part of the base portion 41 of the accommodating partial pipe 4 ahead of the tapered portion 43, the tapered portion 43, and the reduced diameter cylindrical portion 44 when the terminal partial pipe 5 is pulled out from the accommodating partial pipe 4.

[0019] The outer diameter of the base 51 of the terminal partial pipe 5 is smaller than the inner diameter of the reduced diameter cylindrical portion 44 of the accommodating partial pipe 4, and the outer diameter of the expanded diameter cylindrical portion 53 of the terminal partial pipe 5 is larger than the inner diameter of the reduced diameter cylindrical portion 44 of the accommodating partial pipe 4. The terminal partial pipe 5 is extendable and contractible relative to the accommodating partial pipe 4 located at the front, and is fitted and connected when extended.

[0020] When the long-length fore-receiving method is performed during tunnel excavation by driving the ground reinforcement pipe 1 of the embodiment, as shown in FIG. 4(a), for example, the leading pipe 2 is placed on the guide cell 14 of the drilling device, and a drilling rod 11 connected to a drilling machine 15 on the guide cell 14 is inserted into the leading pipe 2. The drilling rod 11 is attached to a drill bit 12 via a casing shoe 13a, and the drill bit 12 is attached to the tip of the leading pipe 2 via the casing shoe 13a. In this state, the driving force of the drilling machine 15 is transmitted to the drill bit 12 via the drilling rod 11, and the leading pipe 2 is pulled and driven into the ground 100 while the drill bit 12 drills the ground 100 immediately adjacent to the tunnel face.

[0021] After most of the leading section pipe 2 has been driven into the natural ground 100, the middle section pipe 3 is placed on the guide cell 14, and the tip of the middle section pipe 3 is connected to the rear end of the leading section pipe 2 with a screw connection, and the components are connected with a screw connection via a coupler, so that the extended drilling rod 11 is inserted into the leading section pipe 2 and the middle section pipe 3. Then, the driving force of the drilling machine 15 is transmitted to the drilling bit 12 via the drilling rod 11, and while the drilling bit 12 is drilling, the leading section pipe 2 and the connected middle section pipe 3 are pulled by the drilling bit 12 and driven into the natural ground 100 (see Figures 4(b) and 5(a)).

[0022] After the leading pipe 2 and the intermediate pipe 3 are driven until most of the intermediate pipe 3 is embedded in the natural ground 100, the encased pipe 4 with the terminal pipe 5 inserted therein is placed on the guide cell 14, as shown in Figure 5(a), and the tip of the encased pipe 4 is connected to the rear end of the intermediate pipe 3 with a screw connection. The components are also connected with a screw connection via a coupler, so that the extended drilling rod 11 is inserted into the leading pipe 2, the intermediate pipe 3, the encased pipe 4, and the terminal pipe 5. The rear end of the terminal pipe 5 is fixed in place so that it cannot move from a predetermined position on the guide cell 14 in the driving direction of the natural ground reinforcement pipe 1. In the illustrated example, a flange 54 attached to the rear end of the terminal pipe 5 is hooked onto the rear surface of a centralizer 16 that supports the natural ground reinforcement pipe 1 so as to center it.

[0023] The driving force of the drilling machine 15 is then transmitted to the drilling bit 12 via the drilling rod 11, and while the drilling bit 12 is drilling, the drilling bit 12 is used to pull the front partial pipe 2 and the connected intermediate partial pipe 3 and encased partial pipe 4, and drive them into the ground 100 (see Figures 5(a) and 5(b)). When the front partial pipe 2 is pulled during drilling, the intermediate partial pipe 3 and encased partial pipe 4 are pulled as well, but the terminal partial pipe 5, which is inserted into the encased partial pipe 4 and has its rear end fixed in a predetermined position on the guide cell 14, is pulled out of the encased partial pipe 4, and the front end of the terminal partial pipe 5 fits into and is connected to the rear end of the encased partial pipe 4. In other words, the ground reinforcement pipe 1 is driven into the ground 100 with the terminal partial pipe 5 pulled out of the encased partial pipe 4.

[0024] After the ground reinforcement pipe 1 is driven and the drilling rod 11 is reversed to release it from the drill bit 12 and withdrawn, a packer 17 made of cloth, rubber, or the like is placed near the tip of the housing partial pipe 4 inside the ground reinforcement pipe 1, and an expansion consolidation material is injected into the packer 17 to expand it, and the expanded packer 17 forms a partition wall (see Figures 6(a) to (c)). Then, a consolidation material S is injected into the front side of the expanded packer 17 using an injection pipe 18 that is inserted into the terminal partial pipe 5 and the housing partial pipe 4 and that is provided so as to pass through the expanded packer 17 (see Figures 6(c) and (d)).

[0025] The injected consolidation material S is filled inside the ground reinforcement pipe 1 on the front side of the packer 17, and is further discharged into the surrounding ground 100 from the discharge holes formed in the ground reinforcement pipe 1 on the front side of the storage partial pipe 4, in this embodiment from the discharge holes 34 of the middle partial pipe 3 and the discharge holes 24 of the front partial pipe 2, and a consolidated area is formed in the ground 100 around the ground reinforcement pipe 1 due to the penetration of the consolidation material S (see Figures 6(d) and (e)).

[0026] Next, as the tunnel excavation progresses and support structures 191 are erected at the locations where the ground reinforcement pipes 1 are to be installed and sprayed concrete 192 is applied, the terminal pipes 5 exposed in the ground 100 to be excavated are inserted back into the housing pipes 4 so that the terminal pipes 5 are housed in the housing pipes 4, and further tunnel excavation, erection of support structures 191, and application of sprayed concrete 192 are carried out (see Figure 6(e)).

[0027] According to the ground reinforcement pipe 1 of this embodiment or the long-length fore-receiving method using the same, the terminal pipe 5 is telescopically mounted relative to the encased pipe 4. This allows the exposed terminal pipe 5 to be housed in the encased pipe 4 during tunnel excavation, eliminating the need to remove the terminal pipe 5 during tunnel excavation. Furthermore, since the work of connecting the encased pipe 4 and the terminal pipe 5 using a screw connection or the like is no longer necessary, the labor required for connecting the pipes that make up the long ground reinforcement pipe 1 is reduced. Furthermore, since no removed terminal pipe 5 is generated during tunnel excavation using the ground reinforcement pipe 1, industrial waste is eliminated when the ground reinforcement pipe 1 is used, and the need for sorting industrial waste is also eliminated. Furthermore, since the work of removing the terminal pipe 5 is eliminated, the situation in which the ground 100 becomes loose due to vibrations caused by the work of removing the terminal pipe 5 is eliminated.

[0028] Furthermore, since it is not necessary to form discharge holes for the consolidation material in the terminal partial pipe 5 that is expected to be housed in the housing partial pipe 4 during tunnel excavation work, or in the housing partial pipe 4 that is expected to house the terminal partial pipe 5, the work of machining discharge holes in the partial pipes located at the rear can be eliminated, thereby reducing manufacturing costs. Furthermore, even without injecting and filling the consolidation material S into the terminal partial pipe 5 and the housing partial pipe 4, the structure becomes a double pipe when the terminal partial pipe 5 is housed in the housing partial pipe 4, so sufficient rigidity can be ensured for the ground reinforcement pipe 1 where the housing partial pipe 4 is installed. Note that it is also preferable to inject and fill the interior of the terminal partial pipe 5 and the housing partial pipe 4 with the consolidation material S after inserting the terminal partial pipe 5 back into the housing partial pipe 4, thereby further increasing the rigidity of the ground reinforcement pipe 1 where the housing partial pipe 4 is installed.

[0029] Furthermore, in the long-length pre-receiving method using the ground reinforcement pipe 1, it is only necessary to inject the consolidation material S into the front side of the packer 17 placed near the tip of the storage section pipe 4, which reduces the amount of consolidation material S injected and reduces construction costs.

[0030] [Scope of the invention disclosed herein] The inventions disclosed in this specification include, in addition to the individual inventions and embodiments listed as inventions, those specified by modifying partial contents of these with other contents disclosed in this specification, those specified by adding other contents disclosed in this specification to these contents, or those specified by deleting partial contents of these to the extent that partial effects can be obtained and creating a generic concept. The inventions disclosed in this specification also include the following contents and modifications.

[0031] For example, the natural ground reinforcement pipe 1 in the above embodiment is configured to have, in order from the tip side corresponding to the deep side of the hole in the natural ground 100, a leading partial pipe 2, one intermediate partial pipe 3, a storage partial pipe 4, and a terminal partial pipe 5 inserted therein by a telescopic mechanism, but it is also suitable to have a configuration in which a plurality of intermediate partial pipes 3 are connected to each other by screw connections behind the leading partial pipe 2, and the storage partial pipe 4 is connected to the intermediate partial pipe 3 located at the rearmost side. Also, if necessary, it is possible to have a configuration in which the storage partial pipe 4 is directly connected to the rear side of the leading partial pipe 2 by screw connections.

[0032] Furthermore, in the long-length pre-receiving method of the above embodiment, the packer 17 is arranged near the tip of the containing partial pipe 4, but it is also possible to arrange the packer 17 in the middle of the containing partial pipe 4, inject the consolidation material S into the ground reinforcement pipe 1 ahead of this packer 17, and then, during subsequent tunnel excavation, insert an end partial pipe 5 shorter than the end partial pipe 5 in the illustrated example back into the containing partial pipe 4. In this case, it is preferable to form a discharge hole for the consolidation material S in the front part of the containing partial pipe 4. [Industrial Applicability]

[0033] The present invention can be used in the long-length fore-receiving method in tunnel excavation work. [Explanation of symbols]

[0034] 1...ground reinforcement pipe 2...head section pipe 21...base 22...female threaded section 23...male threaded section 24...discharge hole 3...middle section pipe 31...base 32...female threaded section 33...male threaded section 34...discharge hole 4...accommodating section pipe 41...base 42...female threaded section 43...tapered section 44...reduced diameter tubular section 5...end section pipe 51...base 52...tapered section 53...expanded diameter tubular section 54...flange 11...drilling rod 12...drilling bit 13, 13a...casing shoe 14...guide cell 15...drilling machine 16...centralizer 17...packer 18...injection pipe 191...shoring 192...shotcrete 100...ground 201...face 202...ground 203...section steel pipe 203a... Terminal steel pipe 204... Ground reinforcement pipe 205... Consolidation material 206... Support 207... Shotcrete T... Tunnel space S... Consolidation material

Claims

1. A long-length pre-supporting method without widening, using a ground reinforcement pipe that has a leading pipe into which a drilling rod can be freely inserted and to which a drilling bit is attached at the tip, and a terminal pipe and a storage pipe into which the terminal pipe is inserted by a telescopic mechanism are provided at the rear, and the terminal pipe is provided so as to be extendable and retractable relative to the storage pipe, a first step of pulling the leading pipe section by drilling a hole with a drill bit attached to the tip, thereby drawing out the terminal pipe section from the storage pipe section and driving the ground reinforcement pipe into the ground; a second step of disposing a packer inside the ground reinforcement pipe near the tip of the containing partial pipe, injecting a consolidation material into the front side of the expanded packer, and discharging the consolidation material into the surrounding ground from a discharge hole formed in the ground reinforcement pipe forward of the containing partial pipe; A long-length pre-supporting method characterized by comprising a third step of inserting the terminal pipe exposed in the ground to be excavated back into the storage pipe as the tunnel is excavated.

2. A long-length pre-receiving construction method as described in claim 1, characterized in that no discharge holes for the consolidation material are formed in the peripheral walls of the terminal portion pipe and the accommodating portion pipe that constitute the ground reinforcement pipe.

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