JP2007146498A - Natural ground reinforcing pipe and tunnel excavating method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a natural ground reinforcing pipe and a tunnel excavating method using the pipe facilitating classified recovery after excavating a tunnel while having sufficient strength when driving the pipe. <P>SOLUTION: The natural ground reinforcing pipe penetrating into a hole as the hole is bored by a boring bit provided on the tip side is constituted by connecting a plurality of steel pipes in an axial direction. The outer peripheral surface of each steel pipe is formed with annular grooves at predetermined spaces in the axial direction, and at least one axially extending slit is formed in a region partitioned by the annular grooves. Slits formed in the adjacent regions are formed in positions shifted from each other in a circumferential direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a natural ground reinforcing pipe that enters into a hole along with a drilling bit provided by a drilling bit provided on the tip side, and a tunnel excavation method using the same.

In tunnel construction for excavating a soft ground, for example, as disclosed in Patent Document 1, a pipe is inserted into a natural ground, and an injection material is injected through the pipe to reinforce the natural ground. In recent years, various methods for reinforcing such ground have been proposed. For example, in the long tip receiving method, a reinforcing pipe is placed obliquely forward around the face and an injection material is injected through the pipe. Thereby, a natural ground reinforcement and improvement are performed by making an injection material infiltrate a natural ground and hardening it. In this case, the laid pipe is left on the ground, and the tunnel is excavated after reinforcing the periphery of the tunnel formation region. On the other hand, in order to reinforce the tunnel formation region, a pipe is placed on the mirror surface, and an injection material is injected in the same manner as described above to reinforce the natural ground. Then, excavation is performed while removing all the installed pipes with an excavator.

At this time, if the pipe is made of steel or iron (steel pipe), the blade of the excavator may be damaged due to its rigidity and strength. For this reason, most of the pipes placed on the mirror surface are formed of glass fiber that can be easily broken, resin materials such as vinyl chloride pipes, reinforced resin pipes, and the like.
Japanese Patent Laid-Open No. 7-76822

  By the way, when breaking the pipe placed on the mirror surface described above, the crushed pieces are dispersed in the excavated earth and sand, so it is very difficult to separate and collect industrial waste and reusable resources. There is a problem that it becomes difficult and a great deal of cost and labor are required for processing as industrial waste. Further, since the reinforced resin pipe is inferior to the steel pipe in rigidity and strength, it cannot be said that it can sufficiently cope with geological changes such as a boulder existing in soft ground when placing the pipe. Furthermore, it cannot be said that the strength of the pipe connection portion is strong, and in the worst case, the pipe connection portion may be broken during the placement of the pipe.

  The present invention has been made in order to solve the above-mentioned problems, and uses a ground reinforcement pipe that has sufficient strength at the time of pipe placement and can be easily separated and collected after tunnel excavation. The purpose is to provide a tunnel excavation method.

  The present invention is a ground reinforcement pipe that enters into a hole along with the drilling by a drilling bit provided on the tip side, and is made to solve the above-described problem, and a plurality of steel pipes are provided. An annular groove is formed on the outer peripheral surface of each steel pipe at a predetermined interval in the axial direction, and the region partitioned by the annular groove extends at least in the axial direction. One slit is formed, and the slits formed in the adjacent regions are formed at positions shifted from each other in the circumferential direction.

  According to this configuration, since the pipe is formed of a steel pipe, it is possible to obtain higher rigidity and strength than a conventional reinforced resin pipe, and it is possible to sufficiently cope with changes in geology of natural ground. In addition, annular grooves are formed at predetermined intervals in a plurality of steel pipes constituting the reinforcing pipe, and slits are formed in regions partitioned by these annular grooves. Therefore, the steel pipe can be easily cut along the annular groove by applying a force after exposing the cast pipe during excavation, so that the pipe can be easily removed. Furthermore, when the injection material is injected into the steel pipe, the steel pipe and the hardened injection material can be easily separated at the same time as the steel pipe is cut along the tubular groove.

  In the pipe, a slit is formed in a terminal region between the rear end of the end pipe arranged at the rearmost among the plurality of steel pipes and the annular groove formed at the rearmost side in the end pipe. Can not be.

  It is preferable that at least one fixing member that extends obliquely outward in the radial direction toward the opposite side of the hole forming direction and elastically swingable radially inward is provided on the outer peripheral surface of the steel pipe. When this fixing member is used, it is possible to prevent the pipe from coming out of the hole together with the drilling rod when, for example, the drilling rod used for the casting is collected after the pipe is placed. That is, since this fixing member extends diagonally outward in the radial direction to the opposite side to the drilling formation direction, when the drilling is formed, the fixing member is elastically rocked radially inward by the wall surface of the hole. Although it does not hinder the entrance of the pipe, if the pipe is pulled out in the direction opposite to the drilling direction, the fixing member swings radially outward and is caught on the wall surface of the hole. Is prevented. If this fixing member has the said structure, it can be made into various shapes, such as rod shape and plate shape. Moreover, although it is preferable to provide in the top steel pipe, it can also provide in another steel pipe. Further, the number is not particularly limited.

  The following effects can also be obtained. In other words, when another steel pipe is added to the rear end after a certain steel pipe has been placed, if the fixing member is attached to the previous steel pipe, the previous steel pipe can be prevented from moving during the addition work. Can do. For example, when a steel pipe is added to the former steel pipe by screwing, when the latter steel pipe is screwed while rotating, the former steel pipe is fixed in the hole by the fixing member, so that it can be prevented from spinning around. . As a result, the steel pipe can be added efficiently and quickly.

  Moreover, the edge part of each slit can be comprised so that it may extend to an adjacent area | region beyond an annular groove. By doing so, when the steel pipe is cut by the annular groove, the slits in the cut area are continuous over the entire length of the area. As a result, each region is surely divided in the axial direction by the slit, so that separation and collection are further facilitated.

  Further, in the connecting portion between the steel pipes, a male screw is formed on the outer peripheral surface of the end portion of one steel pipe, and a female screw that is screwed to the male screw is formed on the inner peripheral surface of the end portion of the other steel pipe. The internal thread forming portion at the end of the other steel pipe can be configured to expand in diameter with substantially the same thickness as the other portions.

  By enlarging the female screw forming portion in this way and ensuring the same thickness as the other portions, sufficient rigidity can be obtained even with a steel pipe having a relatively small diameter and a small thickness. it can. In particular, when the pipe according to the present invention is used for placing a pipe on a mirror surface, a pipe having a small diameter is preferred. Therefore, the above configuration is advantageous.

  Moreover, the tunnel excavation method according to the present invention is made to solve the above-described problem, and includes a step of placing the above-described ground reinforcement pipe on the ground, and a rear end region of the terminal pipe. A step of disposing a stopper to close the terminal pipe, a step of injecting an injection material into the pipe through the plug, and infiltrating the injection material into a natural ground through the slit of each steel pipe; The steel pipe is exposed while excavating the steel pipe, and the steel pipe is bent and cut in the annular groove and divided by the slit, and the steel pipe is removed from the natural ground together with the injecting material. Process.

  According to the natural ground reinforcing pipe according to the present invention, it has sufficient strength when the pipe is placed, and can be easily separated and collected after tunnel excavation.

  Hereinafter, an embodiment of a natural ground reinforcing pipe according to the present invention will be described with reference to the drawings. 1 is an exploded perspective view of a reinforcing pipe according to the present embodiment, FIG. 2A is a cross-sectional view taken along line AA in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. In the following description, the hole forming direction is referred to as the front or front end side, and the opposite side is referred to as the rear or rear end side.

  As shown in FIG. 1, the natural ground reinforcing pipe according to the present embodiment is configured by connecting four steel pipes in the axial direction, and is shown in FIGS. 1 (a) to 1 (d). Steel pipes are connected in order from the top. Hereinafter, these steel pipes will be referred to as a leading pipe 1, a first intermediate pipe 3, a second intermediate pipe 5, and a terminal pipe 7. A drilling bit (not shown) is attached to the tip of the leading pipe 1, and a drilling force, thrust, and rotational force are applied to the drilling bit from a drilling rod inserted into the pipe to perform drilling. . Then, along with the drilling by the drill bit, the reinforcing pipe enters the hole.

  As shown in FIG. 1 (a), the front pipe 1 is formed with four annular grooves 9 at predetermined intervals in the axial direction. Thereby, the front end region 11, the three intermediate regions 13a to 13c sandwiched between the annular grooves, and the rear end region 15 are formed in this order from the top in the top tube 1. The tip region 11 is shorter than the intermediate regions 13a to 13c, and the above-described drill bit is attached. The intermediate regions 13a to 13c are referred to as first, second, and third intermediate regions from the distal end side, and a pair of slits 17 extending in the axial direction are formed in each of the intermediate regions 13a to 13c. As shown in FIG. 2A and FIG. 2B, the slits 17 in each region are formed at positions facing each other in the radial direction across the axis O, and in the adjacent intermediate regions 13a and 13b, It is formed at a position shifted by 90 degrees from each other so that adjacent intermediate region slits do not overlap. Further, as shown in FIG. 1, the end of each slit 17 extends beyond the annular groove 9 to a position slightly entering the adjacent region. Further, the rear end region 15 is short like the front end region 11, and a male screw 19 is formed on the outer peripheral surface of the rear end portion.

  Next, the intermediate pipe will be described with reference to FIGS. 1, 3, and 4. FIG. 3 is an enlarged cross-sectional view (a) and a side view (b) of the distal end portion of the intermediate pipe, and FIG. 4 is a side view showing a connection portion between the steel pipes. Since the first intermediate tube 3 and the second intermediate tube 5 have the same configuration, the first intermediate tube 3 will be described as an example. As shown in FIG. 1 (b), the first intermediate tube 3 has five regions formed by four annular grooves 9 as in the case of the leading tube 1, but the configuration of the tip region 21 is the same as that of the leading tube 1. It is different. That is, as shown in FIG. 3, the tip region 21 is expanded in diameter while ensuring substantially the same thickness as the other regions, and a female screw 20 is formed on the inner wall surface of the expanded portion. Then, the female screw 20 is screwed into the male screw 19 of the leading pipe 1 described above or the male screw 19 of the adjacent intermediate pipe. At this time, as shown in FIG. 4, since the tip region is enlarged, the diameter D of the connecting portion between the steel pipes is larger than the other portions. However, the diameter D of the enlarged diameter portion is smaller than the maximum diameter of the drill bit, so that it does not become a resistance when the pipe enters the hole.

  Next, the terminal tube will be described. As shown in FIG. 1 (d), the terminal pipe 7 is formed with three annular grooves 9, thereby forming four regions in the axial direction. That is, the terminal tube 7 is formed with a tip region 21 having a short length, two intermediate regions 13a and 13b, and a rear end region 23 having substantially the same length as the intermediate region in this order from the top. Here, the tip region 21 and the intermediate region 13 have the same configuration as the intermediate tubes 3 and 5 described above. On the other hand, the rear end region 23 is different from that of the intermediate tubes 3 and 5 in that no slit is formed and no male screw is formed in the rear end portion. That is, it is formed in a cylindrical shape with a constant diameter. Here, the rear end region 23 of the terminal tube 7 in the present embodiment corresponds to a terminal region of the present invention.

  Next, a tunnel excavation method using the reinforcing pipe configured as described above will be described with reference to FIGS. FIG. 5 is a cross-sectional view of the vicinity of the mirror surface where the pipe is placed, FIG. 6 is a view for explaining the removal of the pipe, and FIG. 7 is a view showing the division of the steel pipe. This embodiment is intended for excavation of a tunnel in a soft ground. First, pipes are placed around the face by a long tip receiving method, and then a plurality of the above-mentioned reinforcing pipes are placed on the face mirror surface, and after the ground is improved by injection, the mirror surface is excavated. . Below, the process from the placement of the reinforcing pipe to the excavation of the mirror surface will be described in detail.

  When the reinforcing pipe is placed, concrete 22 (see FIG. 5) is sprayed on the mirror surface to reinforce the surface. Subsequently, a drill bit is attached to the tip of the leading pipe 1 shown in FIG. 1, and a drill rod is inserted from the rear end of the leading pipe 1 to connect with the drill bit. Then, the leading pipe 1 is driven on the mirror surface S while performing drilling by applying a striking force, thrust and rotational force to the drill bit by the drill rod. When the leading pipe 1 has been driven, the first intermediate pipe 3 is connected to the rear end thereof, and the extension rod is connected to the rear end of the drilling rod, and the driving is started again. Thereafter, this operation is repeated, and the second intermediate pipe 5 and the terminal pipe 7 are sequentially connected to place the pipe. Then, when the placement of the plurality of pipes on the mirror surface S is completed, the drilling rod is extracted, and then the insert pipe 29 is inserted into the placed reinforcement pipe. As shown in FIG. 5, the insert tube 29 is provided with a packer 25 at an intermediate portion thereof, and the insert tube 29 is arranged so that the packer 25 is disposed at a predetermined position near the front end of the rear end region 23. Inserted. The packer 25 used here corresponds to the stopper of the present invention and closes the end region.

  Subsequently, caulking 27 is applied to the rear end of the terminal tube 7 and the opening portion of the mirror surface S to close the entire rear end of the terminal tube 7. In this way, the inside of the pipe and the outside of the hole communicate with each other through the insert pipe 29. Then, an injection material such as mortar is press-fitted from the insert pipe 29, and the injection material G is injected into the pipe. The injection material G injected in this way is filled in the pipe and penetrates into the natural ground through the slit 17. Thereafter, the injection material G is solidified inside and outside the pipe, and the natural ground is reinforced.

  Subsequently, the mirror surface is excavated by an excavator. As shown in FIG. 6, during excavation, the pipe is exposed while removing the soil around the pipe. Then, when the annular groove 9 is exposed, the pipe is pressed and bent by the excavator, and the rear end region 23 of the terminal pipe 7 is cut. Following this, every time excavation is performed and the annular groove 9 is exposed, the pipe is pressed and bent, and as shown in FIG. 7, the excavator presses the steel pipe 13 so as to push open the slit 17. And split. As described above, the pipe is cut at the position of the annular groove 9, and the steel pipe 13 is divided into two along the axial direction by the slit 17. Is collected separately. In this way, the cutting of the pipe and the excavation of the natural ground are repeated, and when all of the pipe is removed, a new pipe is driven again and excavation is performed as described above.

  As described above, according to the present embodiment, the annular grooves 9 are formed at predetermined intervals in the plurality of steel pipes constituting the reinforcing pipe, and the slits 17 are formed in the regions partitioned by the annular grooves 9. ing. Therefore, the steel pipe 13 can be easily cut along the annular groove 9 by applying force with an excavator after exposing the cast pipe along with excavation. Therefore, the pipe can be easily removed. Furthermore, since the steel pipe 13 can be divided in the axial direction by applying a force to the slit 17, it is possible to easily separate the injection material G solidified inside and the steel pipe 13 and to separate and collect them. Become. At this time, since the end of each slit 17 extends to the adjacent region beyond the annular groove 9, when the steel pipe 13 is cut by the annular groove 9, the slit 17 in the cut region is the full length of the region. It becomes a continuous thing over. As a result, each region is reliably divided in the axial direction by the slit 17, so that the separate collection is further facilitated.

  Further, in the pipe according to the present embodiment, no slit is formed in the rear end region 23 of the terminal pipe 7 because the injection material G is not scheduled to be injected. This is because concrete has already been sprayed on the mirror surface S, and a certain amount of reinforcement has been made. Therefore, in the vicinity of the rear end region 23 of the end pipe 7 located closest to the mirror surface S, it is necessary to reinforce the natural ground. This is because the injection material does not penetrate into the natural ground and may cause leakage to the outside when the slit is provided in the vicinity of the mirror surface S.

  Furthermore, in this embodiment, since the pipe to be placed on the mirror surface S is targeted, a pipe having a smaller diameter is often used than a pipe used in a normal injection-type long tip receiving method. The thickness of the steel pipe is limited to a thin wall because of the necessity of incorporating a device or the like. On the other hand, in the above-mentioned pipe, at the connecting portion between the steel pipes, the male screw 19 is formed on the outer peripheral surface of one steel pipe end, the diameter of the other steel pipe end is expanded, and the female screw is formed on the inner peripheral surface. 20 is formed. In this way, the female thread forming portion secures the same wall thickness as the other portions by expanding the diameter, so that sufficient rigidity can be obtained even with a steel pipe having a relatively small diameter. During installation, the connection part of the steel pipe is not broken and the construction is not interrupted. Moreover, by using a steel pipe, it is possible to obtain higher mechanical strength than a conventionally used reinforced resin pipe, and it is possible to reduce the cost.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. In the above embodiment, the reinforcing pipe is configured by connecting four steel pipes, but the number of steel pipes constituting the pipe is not particularly limited. For example, by increasing or decreasing the number of intermediate pipes, the total length of pipes can be increased or decreased. Further, the positions and number of the annular grooves and slits formed in the steel pipe can be appropriately changed to those other than the above.

  Moreover, in the said embodiment, although the cement type injection material is used, a urethane type injection material can also be used. However, in this case, since the internal pressure in the pipe is larger than the cement-based injection material, a male screw is formed on the outer peripheral surface of the rear end portion of the terminal tube, and the cap is screwed to this portion. It is also possible to reliably close the pipe.

  By the way, when the placement of the pipe is completed and the drilling rod is extracted, it is considered that the pipe comes out together with the drilling rod. In this case, if the pipe is configured as follows, it can be reliably prevented from coming off. That is, as shown in FIG. 8A, a pair of fixing members 8 may be provided on the outer peripheral surface of the top tube 1. The fixing member 8 is composed of a rod-like member, extends obliquely outward in the radial direction to the opposite side of the hole forming direction X, and can be elastically rocked inward in the radial direction. Since this fixing member 8 extends diagonally outward in the radial direction to the opposite side to the hole forming direction X, as shown in FIG. Swing elastically inward. Therefore, it does not hinder the entrance of the pipe. On the other hand, as shown in FIG. 8C, when the pipe is pulled out in the direction opposite to the hole forming direction X, the fixing member 8 is urged radially outward and swings while the wall surface of the hole is swung. The pipe is prevented from being pulled out.

  The fixing member 8 is also effective when the first intermediate pipe 3 is added after the leading pipe 1 has been driven. That is, when the first intermediate pipe 3 is connected to the top pipe by screwing, if the fixing member 8 is provided in the top pipe 1, the top pipe 1 is fixed in the hole. Even if screwed while rotating, it is possible to prevent the leading pipe 1 from idling. Therefore, the steel pipe can be added efficiently and quickly.

  The fixing member 8 can have various shapes such as a plate shape in addition to the rod shape. Further, it can be provided not only at the top pipe 1 but also at an intermediate pipe or the like. By doing so, the retaining effect is improved and the steel pipe can be quickly added. Further, as described above, only one or three or more may be provided instead of providing two in one steel pipe.

  Moreover, in the said description, although the steel pipes are connected by enlarging the front-end | tip area | region 21 of each steel pipe and screwing in the external thread 19 formed in the rear-end area | region 15 of each steel pipe, It is also possible to enlarge the diameter of the rear end region, form a male screw in the front end region, and screw into this. Moreover, when a steel pipe is cut | disconnected or divided | segmented, if it can provide force other than an excavator, it will not specifically limit.

1 is an exploded perspective view showing an embodiment of a reinforcing pipe according to the present invention. 2A is a cross-sectional view taken along line AA in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. It is sectional drawing (a) and side view (b) of the front-end | tip part of an intermediate tube. It is a side view which shows the connection part of steel pipes. It is sectional drawing of the mirror surface vicinity in which the pipe was laid. It is a figure explaining removal of a pipe. It is a figure which shows the division | segmentation of a steel pipe. It is a perspective view of the top tube which provided the fixing member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Top pipe 3 1st intermediate pipe 5 2nd intermediate pipe 7 End pipe 8 Fixing member 9 Annular groove 17 Slit 19 Male screw 23 Rear end area (terminal area)
25 Packer

Claims (4)

A pipe for reinforcing natural ground that enters the hole along with the drilling by the drilling bit provided on the tip side,
Consists of connecting multiple steel pipes in the axial direction,
An annular groove is formed at a predetermined interval in the axial direction on the outer peripheral surface of each steel pipe,
In the region partitioned by the annular groove, at least one slit extending in the axial direction is formed,
The slits formed in adjacent areas are pipes for reinforcing natural ground formed at positions shifted from each other in the circumferential direction.   The slit is not formed in the terminal field between the rear end of the end pipe arranged in the tail end among the steel pipes, and the annular groove formed in the rearmost part in the end pipe. The pipe for reinforcing natural ground according to 1.   The outer peripheral surface of the steel pipe is provided with at least one fixing member extending obliquely outward in the radial direction toward the opposite side to the drilling direction and elastically swingable inward in the radial direction. Item 3. The natural ground reinforcing pipe according to item 1 or 2. Placing the ground reinforcement pipe according to any one of claims 1 to 3 on the ground;
Placing a plug in the end region of the terminal tube to close the end region;
Injecting an injection material into the pipe through the plug, and infiltrating the injection material into a natural ground through the slits of the steel pipes;
The steel pipe is exposed while excavating a natural ground, and a force is applied to the steel pipe, whereby the steel pipe is bent and cut in the annular groove and divided by the slit, and the steel pipe is grounded together with an internal injection material. A tunnel excavation method with a process of removing from a mountain.

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