JP4145738B2 - Tunnel support method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tunnel support method , and more particularly, to a reinforcement method for an upper half support leg.
[0002]
[Prior art]
In the mountain tunnel construction method, when it is not possible or impossible to deal with by ordinary support works, various auxiliary construction methods are adopted for securing the safety of the tunnel or preserving the surrounding environment. Among these, a leg pile construction method or the like is used as an auxiliary construction method for suppressing the settlement of the leg portion due to insufficient support force of the upper half support leg portion. Patent Document 1 discloses a leg reinforcement method in which a curved reinforcement is provided obliquely downward and forward from the face of a tunnel.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-147164 (page 3, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, each of the above-mentioned leg reinforcement methods involves work on each face, so that there is a problem that the construction period becomes long and the construction cost increases. Moreover, it is difficult to integrate the leg portion reinforcing portion and the upper half support work, and a certain leg portion supporting force may not be obtained.
The present invention has been made in view of the above-described problems, and provides a tunnel support structure and a tunnel support method capable of reliably obtaining the support force of the upper half support legs and improving the excavation efficiency. Objective.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, in the tunnel support method according to the present invention, before excavating the upper half, along the tunnel axis direction at a position below the upper half support leg, the ground improvement by a long tip receiving work is performed. A tunnel support method in which the upper half support leg is supported by the ground improvement part when the upper half is excavated and the upper half support is installed. The receiving work is drilled while correcting the drilling trajectory from the tunnel wellhead to the front, with a predetermined separation interval in the ground part below the upper half support leg, and inserting the pipe body When performing the above-described drilling, an outer tube having an outer tube bit having a shape that generates a force that deflects the drilling direction in the first direction at the time of drilling, and a second drilling direction at the time of drilling. An inner tube having an inner tube bit having a shape that generates a force deflecting in the direction of During linear drilling, the circumferential direction of the outer tube bit and the inner tube bit is such that the force that deflects the drilling direction in the first direction and the force that deflects the drilling direction in the second direction cancel each other. Set the relative position and perform drilling with the striking force.When correcting the drilling direction, in the resultant direction of the force that deflects the drilling direction in the first direction and the force that deflects the drilling direction in the second direction In order to enable drilling, the outer tube bit and the inner tube bit are set in a circumferential relative position to perform drilling with a striking force.
At this time, the distal end surfaces of the outer tube bit and the inner tube bit are formed so as to have an inclination angle with respect to a surface orthogonal to the axial direction of the outer tube bit and the inner tube bit, respectively. Is preferred.
[0006]
In the present invention, the lower part from the upper half support leg is improved in advance by receiving work in advance, thereby suppressing the settlement of the upper half support leg and obtaining a reliable support force. In addition, in the long tip receiving work, since the ground is improved before tunnel excavation, the preceding displacement before reaching the face can be reduced, and the effect of suppressing the ground surface settlement is great.
The conventional long tip receiving work is to reinforce the natural ground by filling an injection material in and around the steel pipe after drilling and placing a steel pipe having a length of about 10 to 15 m. In the long tip receiving work in the present invention, it is an ultra long tip receiving work of about 100 m. Therefore, it is necessary to perform drilling while correcting the drilling track in the long tip receiving work in the present invention. However, since the ground is improved by about 100 m at a time, the construction period is shortened compared with the conventional method. Construction cost can be reduced.
When the outer tube bit and the inner tube bit have a tip end surface having an inclination angle, the outer tube bit and the inner tube bit are directed in a direction toward the tip of the inclined surface having a small resistance against the drilling reaction force of the ground. I will escape. The present invention is an application of this principle. When straight running, drilling is performed so that the force that deflects the outer tube bit and the force that deflects the inner tube bit cancel each other. By drilling using the resultant force of the deflecting force and the force deflecting the inner tube bit, a long drilling is possible.
[0009]
Alternatively, in the tunnel support method according to the present invention, before excavating the upper half, along the tunnel axis direction at the lower position of the upper half support legs, construct a natural ground improvement part by a long tip receiving work, When excavating the upper half and installing the upper half support work, it is a tunnel support method that supports the upper half support leg to the natural ground improvement part, the long tip receiving work, Drilling a hole while correcting the drilling track from the tunnel wellhead to the front, with a predetermined separation interval in the ground part below the upper half support leg, inserting the pipe, When the hole is formed, an outer tube having an outer tube bit at the distal end and an inner tube having an inner tube bit shoe at the distal end are provided, and the inner tube bit shoe extends radially from the axis of the inner tube bit shoe. Possible reamer pieces, and during straight drilling, the reamer pieces Performs drilling by impact force in a state stored in the bit shoe, at the time of drilling direction correcting, it is characterized by performing the drilling by striking force the reamer piece as a state of being extended from the inner tube bits shoe.
In the present invention, by extending the reamer piece from the inner pipe bit shoe, the center of the drilling surface is decentered from the axis of the inner pipe bit shoe, so that the drilling direction can be corrected.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of an embodiment of a tunnel support structure according to the present invention.
As shown in this figure, in the tunnel support structure according to the present embodiment, as in the conventional tunnel support structure, the upper half support work 3 made of steel support work and shotcrete is installed on the inner periphery of the upper half 6 of the tunnel. ing. On the outer peripheral portion of the upper half support 3, a long tip receiving work 2 is disposed substantially parallel to the tunnel axis direction at a predetermined spacing in the tunnel circumferential direction, and the lock bolt 5 is arranged in a direction perpendicular to the tunnel axis. They are arranged radially. Moreover, the lining concrete 4 is installed inside the upper half support 3.
In the tunnel support structure according to the present embodiment, in addition to the conventional tunnel support structure, a long tip constructed in the tunnel axis direction on the ground mountain G portion along the substantially tunnel wall surface below the upper half support work tripod. The ground has been improved by receiving work. And in this invention, this elongate tip receiving work is the ultra-long elongate receiving work 1 of a unit of about 100 m.
The ultra-long tip receiving construction 1 is a construction method in which a steel pipe as a core material is drilled and placed, and a natural ground improvement material is injected and filled into the inner and outer circumferences to form the natural ground improvement portion 9. The super-long leading edge receivers 1 are arranged at a separation interval such that the improved portions 9 overlap each other. Moreover, the natural ground improvement part 9 is constructed so that an upper half supporting work 3 leg part is included in the upper part, and the lower part is constructed to the vicinity of the invert 8.
In addition, in order to secure the support ground G support force of the upper half support work 3 legs, the super long tip receiving work 1 is not arranged in a single row but in a vertical row in the natural ground G portion below the upper support work 3 legs. Sometimes it is arranged.
In the tunnel support structure according to the present embodiment, the lower part from the upper half support work 3 leg part is improved in advance by the ultra-long tip receiving work 1 to suppress the settlement of the upper half support work 3 leg part. A reliable supporting force can be obtained. In addition, since the super long tip receiving work 1 improves the natural ground before tunnel excavation, it is possible to reduce the preceding displacement before reaching the face and to suppress the ground surface settlement.
Further, in the tunnel support structure according to the present embodiment, since it is a very long tip receiving work 1 in units of about 100 m, it is possible to shorten the construction period and reduce the construction cost compared with the conventional construction method, and it is uniform in the tunnel axis direction. Since it can be improved, the effect of suppressing uneven settlement is great.
[0011]
In the tunnel support work according to the present embodiment, the upper half 6 of the tunnel excavation section is excavated in advance and the upper half support work 3 is installed. The super long tip receiving work 1 is constructed in the tunnel axial direction in the part extending from the tunnel to the lower half 7 of the tunnel. The construction of this long tip receiving construction 1 is determined by the state of the natural ground G, but when constructing from the beginning, when constructing from the tunnel entrance to the front of the tunnel and constructing a section in the middle of the tunnel The side of the tunnel is partially widened to form a construction space, and construction is performed from there. In any case, since the construction length of the ultra-long length receiving work 1 is about 100 m, when the tunnel is longer than that and fully extended, the side portion is partially expanded in the middle of the tunnel. .
[0012]
Next, although it is a concrete embodiment of the super-long tip receiving, FIG. 2 shows a first embodiment of a drilling method in the super-long tip receiving. FIG. 3 is a perspective view of the outer tube bit and the inner tube bit in the first embodiment of the hole drilling method. However, the bit blade 15 is omitted in FIG. Hereinafter, the same components as those in FIG.
In the drilling method according to the present embodiment, the base end of a double pipe composed of an outer pipe (steel pipe) 10 and an inner pipe (steel pipe) 11 is connected to a drilling driving device (not shown), and the double pipe is connected to the double pipe. carry out the drilling of natural ground G in addition a striking force. An outer tube bit 12 is provided at the distal end of the outer tube 10, and the distal end surface of the outer tube bit 12 has an inclination angle with respect to a plane orthogonal to the axial direction of the outer tube bit 12. On the other hand, an inner tube bit 13 is provided at the distal end of the inner tube 11, and the distal end surface of the inner tube bit 12 has an inclination angle with respect to a plane orthogonal to the axial direction of the inner tube bit 13. In addition, a large number of bit blades 15 are disposed on the distal end surfaces of the outer tube bit 12 and the inner tube bit 13. Furthermore, a measuring device 14 for confirming the drilling direction is provided in the inner tube 11 behind the inner tube bit 13.
At the time of straight hole drilling, as shown in FIGS. 2 (a) and 3 (a), the relative positions of the distal end surface of the outer tube bit 12 and the distal end surface of the inner tube bit 13 are set to the axes of the outer tube bit 12 and the inner tube bit 13. The center is set as a rotation axis at a position of 180 degrees in the circumferential direction, and drilling is performed in the linear direction L1 while confirming the drilling direction with the measuring device 14.
When the drilling direction is corrected, as shown in FIGS. 2B and 3B, the relative positions of the distal end surface of the outer tube bit 12 and the distal end surface of the inner tube bit 13 are set to the axis of the outer tube bit 12 and the inner tube bit 13. The center is set as a rotation axis at a position of 0 degrees in the circumferential direction, and drilling is performed in the deflection direction B1 while confirming the drilling direction with the measuring device 14. At this time, the relative position of the distal end surface of the outer tube bit 12 and the distal end surface of the inner tube bit 13 may not be a position of 180 degrees in the circumferential direction about the axis of the outer tube bit 12 and the inner tube bit 13 as a rotation axis. Drilling may be performed in the deflection direction B1 by setting the position at a degree or 90 degrees.
[0013]
FIG. 4 shows a second embodiment of the hole drilling method in the ultra-long tip receiving work.
In the hole drilling method according to the present embodiment, a double pipe comprising an outer pipe (steel pipe) 20 having an outer pipe bit 22 at the tip and an inner pipe 21 having an inner pipe bit shoe (steel pipe) 23 at the tip is used. To do. On the side surface of the inner tube bit shoe 23, a reamer piece 25 is provided that can extend radially from the axis of the inner tube bit shoe 23. When the reamer piece 25 is stored on the side surface of the inner tube bit shoe 23, the center of the drilling surface substantially coincides with the axis of the inner tube bit shoe 23, and the reamer piece 25 is extended from the inner tube bit shoe 23. The center of the drilling surface is eccentric from the axis of the inner tube bit shoe 23. A measuring device 24 for confirming the drilling direction is provided in the inner tube 21 behind the inner tube bit shoe 23.
At the time of straight hole drilling, as shown in FIG. 4A, the reamer piece 25 is stored in the side surface of the inner pipe bit shoe 23, and the hole is drilled in the linear direction L2 while checking the hole drilling direction with the measuring device 24. .
When the drilling direction is corrected, as shown in FIG. 4B, the reamer piece 25 is extended from the inner pipe bit shoe 23, and the drilling direction is confirmed in the deflection direction B2 while checking the drilling direction with the measuring device 24. Do.
A plurality of reamer pieces 25 may be provided on the inner tube bit shoe 23.
[0014]
As described above, after drilling by the drilling method according to the first or second embodiment, the inner pipes 11 and 21 are pulled out, and the improved material is injected into the outer pipes 10 and 20 and the outer pipes 10 and 20 outside. By doing so, the natural ground improvement part 9 larger diameter than the outer tubes 10 and 20 is formed. This natural ground improvement part 9 comes to have a support function by constructing so that it may overlap (wrap) mutually. In the present embodiment, the super-long tip receiving work 1 is formed downward from the upper half supporting work 3 leg portion to support the upper half supporting work 3. In addition, since the construction length is long, it is preferable that the outer pipes 10 and 20 are perforated pipes and the sections are divided and injected using a packer or the like when the improved material is injected and filled.
When the construction of the natural ground improvement portion 9 by the super long tip receiving work 1 is completed, the upper half 6 is excavated, and the upper half support work 3 is supported by the natural ground improvement portion 9 and installed. After that, the lower half 7 is excavated, but the lock bolt 5 is driven from the gap between the steel pipes (outer pipes 10 and 20) of the super-long-length receiver 1 in parallel, and the tunnel wall of the lower half 7 (natural ground) It is also possible to reinforce the improved portion 9).
[0015]
【The invention's effect】
As described above, according to the tunnel support method according to the present invention, the support force of the upper half support legs can be obtained reliably, and the excavation efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an embodiment of a tunnel support structure according to the present invention.
FIG. 2 is a diagram showing a first embodiment of a drilling method in an ultra-long tip receiving work.
FIG. 3 is a perspective view of an outer tube bit and an inner tube bit in a first embodiment of a drilling method in an ultra-long tip receiving work.
FIG. 4 is a diagram showing a second embodiment of a drilling method in an ultra-long tip receiving work.
[Explanation of symbols]
1 …… Super-long edge receiving 2 …… Long edge receiving 3 …… Upper half support 4 …… Liding concrete 5 …… Lock bolt 6 …… Upper half 7 …… Lower half 8 …… Invert 9 ...... Machiyama improvement part 10, 20 ... Outer pipe 11, 21 ... Inner pipe 12, 22 ... Outer pipe bit 13 ... Inner pipe bit 14, 24 ... Measuring device 15 ... Bit blade 23 ... Inner Tube bit shoe 25 ... Reamer piece G ... Natural ground L1, L2 ... Linear direction B1, B2 ... Deflection direction

Claims (3)

Before excavating the upper half, construct a ground improvement part by a long tip construction along the tunnel axis direction at a position below the upper half support leg, and excavate the upper half to support the upper half When installing a work, it is a tunnel support method for supporting the upper half support leg to the natural ground improvement part,
The long tip receiving work performs drilling while correcting the drilling track from the tunnel wellhead to the front side at a predetermined separation interval with respect to the natural ground part below the upper half support leg, and Insert the body,
In performing the drilling, an outer tube having an outer tube bit having a shape that generates a force that deflects the drilling direction in the first direction during drilling, and the drilling direction in the second direction during drilling. An inner tube having an inner tube bit having a shape that generates a deflecting force at the tip;
During linear drilling, the circumferential direction of the outer tube bit and the inner tube bit is such that the force that deflects the drilling direction in the first direction and the force that deflects the drilling direction in the second direction cancel each other. Set the relative position and drill with the impact force,
When correcting the drilling direction, the outer pipe bit and the inner pipe can be drilled in the resultant direction of the force that deflects the drilling direction in the first direction and the force that deflects the drilling direction in the second direction. A tunnel support method characterized by setting the relative position in the circumferential direction of the bit and drilling with impact force. The distal end surfaces of the outer tube bit and the inner tube bit are formed so as to have an inclination angle with respect to a surface perpendicular to the axial direction of the outer tube bit and the inner tube bit, respectively. The tunnel support method according to claim 1 . Before excavating the upper half, construct a ground improvement part by a long tip construction along the tunnel axis direction at a position below the upper half support leg, and excavate the upper half to support the upper half A tunnel support method for supporting the upper half support leg to the natural ground improvement part when installing a work,
The long tip receiving work performs drilling while correcting the drilling track from the tunnel wellhead to the front side at a predetermined separation interval with respect to the natural ground part below the upper half support leg, and Insert the body,
In performing the drilling, an outer tube having an outer tube bit at the distal end and an inner tube having an inner tube bit shoe at the distal end are provided, and the inner tube bit shoe is radial from the axis of the inner tube bit shoe. Has an extendable reamer piece,
At the time of straight hole drilling, drilling by striking force is performed with the reamer piece stored in the inner pipe bit shoe,
A tunnel support method characterized by drilling by striking force with the reamer piece extended from the inner pipe bit shoe when correcting the drilling direction .

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