KR102365041B1 - Tunnel excavation method using free surface and tunnel excavation device for formation of free surface - Google Patents

Abstract

The present invention relates to a tunnel excavation method using the free surface and a tunnel excavation apparatus for forming the free surface. The present invention relates to the tunnel excavation method using the free surface which can reduce an excavation cost by simplifying a structure, reduce risk of failure during an excavation process, and improve excavation efficiency, and the tunnel excavation apparatus for forming the free surface. For this purpose, the tunnel excavation method using the free surface according to the present invention comprises the following steps of: forming the free surface while drilling along a virtual excavation line; and excavating after blasting an excavation target space surrounded by the free surface. The step of forming the free surface includes the following steps of: dividing the virtual excavation line into n unit areas (n is an integer equal to or greater than 2); and perforating so that the free surface is simultaneously formed in the unit area.

Description

Tunnel excavation method using free surface and tunnel excavation apparatus for forming free surface

The present invention relates to a tunnel excavation method using a free surface and a tunnel excavation apparatus for forming a free surface. It relates to a tunnel excavation method using a free surface and a tunnel excavation apparatus for forming a free surface.

Since tunnel excavation in downtown has a large impact on the surrounding environment, the application of general blasting is limited, and measures to reduce noise and vibration are required. As a measure to reduce noise and vibration applied to tunnel excavation in downtown areas, smooth blasting, pre-splitting Control blasting such as splitting, cushion blasting, and line drilling, and TBM (Tunnel Boring Machine) method, an excavation method that simultaneously excavates the front end of the tunnel using an automated machine, are applied.

However, the control blasting as described above has a problem in that the unit cost of excavation increases due to the divided blasting of the excavation section, reduction of the excavation field, the increase in the number of drillings, and the increase in the amount of primer used accordingly. In addition, the TBM method has poor applicability to changes in rock quality, limited excavation routes, expensive mechanical equipment, and excessive cost of auxiliary equipment such as high wiring to operate it, thereby lowering economic efficiency.

Recently, in tunnel blasting, a partial free surface is formed on the excavation surface using mechanical equipment such as a wire saw, and in parallel with controlled blasting, the free surface blasting method is partially used to reduce the blast vibration and to increase the crushability and excavation efficiency. It is being tested and applied in domestic and overseas fields.

The wire saw cutting method that is being tested and applied to the existing tunnel is a reverse hitting method, which cuts from the front of the makjangmyeon using a jig device, pulley, and guide pulley. The reverse hitting method requires a jig device and pulley of various sizes depending on the cutting depth, and a core (hole) drilling of about 380 mm or more is required so that the jig device and pulley can be inserted to the cutting depth. In addition, the lower pulley of the jig device may be broken due to rock dust and sludge generated during cutting, and the cutting efficiency is 35 ~ There is a problem with a 40% reduction.

In addition, the degree of crushing of rocks by blasting directly affects the subsequent processes leading to loading, transport, and secondary crushing, and the excavation efficiency directly affects the construction period. It is a factor that must be considered essential to secure overall economic feasibility.

Korean Patent Registration No. 10-1508205

The technical problem to be solved in the present invention is to reduce the excavation unit cost by simplifying the configuration, reduce the risk of failure in the excavation process, and improve the excavation efficiency. An object of the present invention is to provide a tunnel excavation device.

The technical problems to be solved in the present invention are not limited thereto, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

The tunnel excavation method using a free surface according to the present invention for solving the above technical problem includes the steps of forming a free surface while drilling along a virtual excavation ship, and excavating after blasting the excavation target space surrounded by the free surface The step of forming the free surface includes: dividing the virtual excavation ship into n unit areas (n is an integer greater than or equal to 2); and drilling so that the free surface is simultaneously formed in the unit area. includes

In this case, the step of perforating so that the free surface is simultaneously formed in the unit area includes the step of perforating so that the free surface is simultaneously formed in the first unit area, and the free surface is simultaneously formed in the second unit area adjacent to the first unit area It may include the step of sequentially perforating as possible.

In this case, the step of drilling so that the free surface is simultaneously formed in the unit area may be a step of drilling using a drilling device in which a plurality of drilling bits are arranged along the width direction.

In this case, the step of drilling using the drilling device may include arranging a first bit disposed forward in the axial direction at a reference position within the unit area.

At this time, the step of drilling using the drilling device may further include the step of prior hitting so that the axial front part of the first bit is inserted into the reference position after the step of arranging the first bit at the reference position can

At this time, the step of drilling using the drilling device is a step of confirming whether the first bit has hit the original position in advance after the step of hitting the front part of the first bit in the axial direction to be inserted into the reference position may further include.

At this time, the step of drilling using the drilling device is such that the second bit disposed axially rearward is inserted into the unit area after the step of preceding striking so that the axial front part of the first bit is inserted into the reference position. It may further include the step of hitting the trailing.

At this time, the step of drilling using the drilling device is a step of hitting the second bit after hitting the first bit in advance in a state in which the first bit and the second bit are partially overlapped along the width direction. can

On the other hand, the tunnel excavation apparatus for forming a free surface according to the present invention operates a bit portion in which a plurality of drilling bits are arranged along the width direction so that a free surface is simultaneously formed in a unit area formed along a virtual excavation line, and the bit portion and a driving unit for providing a driving force to do so, wherein the punched bit may include a first bit disposed in the front in the axial direction and a second bit disposed in the rear in the axial direction.

In this case, the tip of the first bit may be provided with a contact surface supported in contact with a reference position within the unit area.

In this case, the first bit and the second bit may be partially overlapped with each other in the width direction.

In this case, the driving unit may include a single driving motor and a single driving shaft connected to the rotation shaft of the driving motor so that the driving force is simultaneously transmitted to the plurality of perforated bits.

In this case, a plurality of worms corresponding to each of the drilling bits may be provided on the drive shaft, and a worm gear corresponding to the worms may be provided on the plurality of drilling bits, respectively.

According to the present invention, the tunnel excavation method using a free surface according to the present invention and the tunnel excavation apparatus for forming a free surface according to the present invention divide a virtual excavation ship into a plurality of unit areas and then drill a hole so that a free surface is simultaneously formed within the unit area. By doing so, the configuration is simplified and it is possible to reduce the excavation cost.

In addition, by using a drilling device in which a plurality of drilling bits are arranged along the width direction, the risk of failure in the excavation process is reduced by drilling so that a free surface is simultaneously formed in the unit area.

In addition, since the reference position of the punching bit is set by using the first bit to hit ahead, the trailing blow of the second bit can be made at an accurate position, so that the digging efficiency is improved.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a flowchart illustrating a tunnel excavation method using a free surface according to an embodiment of the present invention.
2 is a front view illustrating a virtual excavation ship and an excavation target space according to an embodiment of the present invention.
3 is a front view illustrating a state in which a free surface is formed along an excavation ship according to an embodiment of the present invention.
4 is a flowchart illustrating a step of forming a free surface according to an embodiment of the present invention.
5 is a front view illustrating a state in which an excavation ship is divided into a plurality of unit areas according to an embodiment of the present invention.
6 is a flowchart illustrating a step in which a plurality of unit areas are perforated according to an embodiment of the present invention.
7 is a flowchart illustrating a step of drilling using a drilling device according to an embodiment of the present invention.
8 is a plan view showing a drilling device according to an embodiment of the present invention.
9 is a side view showing a drilling device according to an embodiment of the present invention.
10 is a side view illustrating a state in which a punching bit is disposed to punch each unit area according to an embodiment of the present invention.
11 is an enlarged plan view of a part of a punched bit according to another embodiment of the present invention.
12 is a perspective view showing a drilling device according to another embodiment of the present invention.
13 is an enlarged perspective view of the driving unit of the drilling device according to another embodiment of the present invention.
FIG. 14 is a cross-sectional view of portion I-I of FIG. 13 .

Words and terms used in the present specification and claims are not limited to their ordinary or dictionary meanings, but in accordance with the principle that the inventor can define terms and concepts in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea.

Therefore, the embodiments described in this specification and the configurations shown in the drawings correspond to a preferred embodiment of the present invention, and do not represent all of the technical idea of the present invention, so that the configuration may be replaced by various There may be equivalents and variations.

In this specification, terms such as "comprises" or "have" are intended to describe the existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but one or more other features It should be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

The presence of an element "in front", "behind", "above" or "below" of another element means that, unless otherwise specified, it is directly in contact with another element, such as "front", "rear", "above" or "below". It includes not only being disposed at the “lower side” but also cases in which another component is disposed in the middle. In addition, that a component is "connected" with another component includes not only direct connection to each other, but also indirect connection to each other, unless otherwise specified.

Hereinafter, a tunnel excavation method using a free surface and a tunnel excavation apparatus for forming a free surface according to the present invention will be described with reference to the drawings. Here, the A direction is the axial direction of the drilling device, and the W direction means the width direction of the drilling device. In order to clearly explain the present invention, parts not related to the description are omitted from the drawings.

1 is a flowchart illustrating a tunnel excavation method using a free surface according to an embodiment of the present invention, FIG. 2 is a front view showing a virtual excavation ship and an excavation target space according to an embodiment of the present invention, FIG. 3 is a front view showing a state in which a free surface is formed along an excavation ship according to an embodiment of the present invention, FIG. 4 is a flowchart illustrating the step of forming a free surface according to an embodiment of the present invention, and FIG. 5 is It is a front view showing a state in which the excavation vessel according to an embodiment of the present invention is divided into a plurality of unit areas.

As shown in Figure 1, the tunnel excavation method using a free surface according to the present invention is a step (S1) of forming a free surface (Fs) while drilling along a virtual excavation line (K), and a free surface (Fs) Including a step (S2) of excavating after blasting an excavation target space (Ts) surrounded by Including the step (S100) of dividing the unit area (Ku) of the above integer), and the step (S200) of drilling so that the free surface (Fs) is simultaneously formed in the unit area (Ku).

That is, as shown in FIG. 3 , in a state in which the virtual excavation ship K and the excavation target space Ts are set, as shown in FIG. 2 , first drilling is performed along the virtual excavation line K. When the excavation target space Ts is blasted in the state in which the free surface Fs is formed in this way, it is possible to effectively prevent vibration and noise from being transmitted to the surroundings. In addition, since a space in which the excavation target space Ts can be expanded is secured during blasting, the excavation target space Ts can be easily destroyed, and rapid excavation is possible while removing it.

As shown in FIG. 4 , in order to form a free surface Fs, a virtual excavation ship K is first divided into n unit areas Ku (n is an integer greater than or equal to 2), and the excavation ship K When this is divided, the perforations are made so that the free surface Fs is formed in each unit area Ku, but the free surface Fs in the unit area Ku is perforated so that the free surface Fs is formed at the same time. That is, as shown in FIG. 5 , if only the number of unit areas Ku formed by perforating so that the free surface Fs is formed at the same time when the unit area Ku is drilled is drilled free along the virtual excavation line K Since all the surfaces Fs are formed, it is possible to quickly and simply form the free surface Fs.

That is, the tunnel excavation method using the free surface according to the present invention and the tunnel excavation apparatus for forming the free surface divide the virtual excavation ship K into a plurality of unit areas Ku and then free in the unit area Ku. By drilling so that the face Fs is formed at the same time, the configuration is simplified and the excavation cost can be reduced.

6 is a flowchart illustrating a step in which a plurality of unit areas are perforated according to an embodiment of the present invention.

As shown in FIG. 6 , the step of perforating so that the free surface Fs is simultaneously formed in the unit area Ku ( S200 ) is a step of perforating so that the free surface Fs is simultaneously formed in the first unit area Ku1 . It may include (S200') and sequentially drilling (S200″) so that the free surface Fs is simultaneously formed in the second unit region Ku2 adjacent to the first unit region Ku1 ( S200 ″).

That is, as described above, the perforations are performed so that the free surface Fs is simultaneously formed in each unit area Ku, and the second unit area Ku1 is perforated and then the second unit area Ku2 is perforated sequentially. will proceed

However, the first unit area Ku1 and the second unit area Ku2 are not continuously formed, but may be configured to be spaced apart from each other by a predetermined distance. As the first unit area (Ku1) and the second unit area (Ku2) are spaced apart from each other by a predetermined distance, even if the free surface (Fs) is not formed, the free surface (Fs) This is because the unformed part can also be destroyed.

Alternatively, it is also possible to simultaneously drill a plurality of unit areas Ku using a plurality of drilling devices 1 .

7 is a flowchart illustrating the step of drilling using a drilling device according to an embodiment of the present invention, Figure 8 is a plan view showing a drilling device according to an embodiment of the present invention, Figure 9 is of the present invention It is a side view showing a drilling device according to an embodiment.

As shown in FIG. 7, the step (S200) of perforating so that the free surface Fs is simultaneously formed in the unit area Ku is a perforating device in which a plurality of perforating bits 110 are arranged along the width direction W ( It may be a step (S210) of drilling using 1).

In this way, if the plurality of drilling bits 110 are arranged along the width direction W using the drilling device, it is possible to drill so that the free surface Fs is simultaneously formed in the unit area Ku having a predetermined length.

In addition, if a plurality of drilling bits 110 are arranged along the width direction W by using the drilling device 1 to form a free surface in the unit area Ku at the same time, the drilling is performed through the drilling device 1 . As the number of drilling is reduced, the risk of failure in the excavation process is reduced.

As shown in FIG. 8 , a plurality of perforated bits 110 are provided along the width direction W, and a driving unit 200 that provides a driving force to operate each perforated bit 110 is provided. It is preferable that the length of the perforated bit 110 in the width direction (W) formed while being provided in plurality along the width direction (W) corresponds to the length of the unit region (Ku). That is, it is configured to be able to adjust the number of punched bits 110 arranged in the width direction W in accordance with the formation length of the unit region Ku. At this time, as shown in FIG. 9 , the plurality of punched bits 110 may be configured to be disposed at the same height while maintaining a horizontal level.

10 is a side view illustrating a state in which a punching bit is disposed to punch each unit area according to an embodiment of the present invention.

As shown in FIG. 7 , the step (S210) of drilling using the drilling device 1 is a reference position (P) in the unit area (Ku) of the first bit (111) disposed in the front in the axial direction (A) It may include a step (S211) of arranging the .

That is, as shown in FIG. 10 , the plurality of punching bits 110 provided in the punching device 1 are disposed along the width direction W, and the first bit 111 disposed in front of the axial direction A ) and a second bit 112 disposed at the rear in the axial direction (A), and the first bit 111 disposed at the front in the axial direction (A) at a reference position (P) in the unit area (Ku) By placing it in the remaining punched bit 110 is configured to be placed in the correct position.

At least one of these first bits 111 may be provided to set a reference so that the punched bits 110 are placed in the correct positions. For example, as shown in FIG. 10 , when two first bits 111 are provided, two reference positions P may be formed to match the number of first bits 111 .

As shown in Figure 7, the step (S210) of drilling using the drilling device (1) is a first bit (111) after the step (S211) of arranging the first bit (111) at the reference position (P) (S211) It may further include a step (S212) of hitting the front part of the axial direction (A) to be inserted into the reference position (P).

Before the full-scale drilling operation in the unit area (Ku) starts, a plurality of drilling bits 110 ) will be able to confirm that it can hit the exact position.

At this time, as shown in FIG. 7 , the step (S210) of drilling using the punching device 1 is a preceding blow so that a part of the front part of the axial direction (A) of the first bit 111 is inserted into the reference position (P). After the step (S212) of performing the step (S213) may further include a step (S213) of checking whether the first bit 111 has hit the original position in advance.

As described above, in the state in which the first bit 111 is arranged to hit the reference position P, the axial direction A of the first bit 111 precedes a portion of the front portion to be inserted into the reference position P When hitting, the hitting position of the first bit 111 is fixed and at the same time the second bit 112 can also be hit while being placed in the correct position, thereby improving the quality of the drilling work. In addition, as described above, the operator checks whether the first bit 111 hits the correct position after the preceding hitting of the first bit 111 , so that the first bit 111 as well as the second bit 112 are wrong It becomes possible to prevent in advance from hitting the position.

In addition, as shown in Figure 7, the step (S210) of drilling using the drilling device (1) is a preceding blow so that a part of the front part of the axial direction (A) of the first bit (111) is inserted into the reference position (P) After the step (S212) of the second bit 112 disposed in the rear axial direction (A) may further include a step (S214) of hitting the rear so as to be inserted into the unit area (Ku).

In a state in which the first bit 111 is disposed at the reference position P, the second bit 112 is also preceded by a blow so that the front part of the first bit 111 is inserted into the reference position P ), it is possible to perforate the unit area (Ku) through the first bit 111 and the second bit 112 by hitting the rear so as to be inserted into the. Through this, when the drilling operation of one unit area (Ku) is completed, the drilling operation of another neighboring unit area (Ku) is performed.

11 is an enlarged plan view of a part of a punched bit according to another embodiment of the present invention.

As shown in FIG. 7 , the step (S210) of drilling using the drilling device 1 is performed in a state in which the first bit 111 and the second bit 112 are partially overlapped along the width direction (W). After the first bit 111 strikes in advance, the second bit 112 may hit the trailing step (S214).

That is, as shown in FIG. 11 , the first bit 111 and the second bit 112 are configured to form a constant overlap length d along the width direction W. When configured in this way, the portion remaining while the first bit 111 is struck in advance is punctured while the second bit 112 is struck in a trailing manner, so that a continuous free surface Fs can be formed in the unit area Ku. will be. For example, as shown in FIG. 11 , two first bits 111 may be provided, and three second bits 112 may be provided on both sides of the first bit 111 . Alternatively, one first bit 111 may be provided, and two second bits 112 may be provided on both sides of the first bit 111 . The quantity of the first bit 111 and the second bit 112 can be adjusted according to the conditions of the tunnel excavation site and the size of the unit area Ku.

At this time, even if the first bit 111 and the second bit 112 are partially overlapped, as described above, the first bit 111 is disposed forward in the axial direction A, and the second bit 112 is relatively Since it is disposed behind the axial direction (A), even when the first bit 111 and the second bit 112 operate at the same time, mutual interference is prevented from occurring, thereby enabling a stable operation. The distance in the axial direction (A) where the front ends of the first bit 111 and the second bit 112 are spaced apart from each other is a distance at which mutual interference does not occur considering the operation method of the first bit 111 and the second bit 112 . It is preferably formed by

That is, as described above, since the reference position of the punching bit 110 is set in such a manner that the first bit 111 is used to hit the front, the trailing blow of the second bit 112 can be made at the correct position, so that the drilling Efficiency is improved.

Figure 12 is a perspective view showing a drilling device according to another embodiment of the present invention, Figure 13 is a plan view showing a drilling device according to another embodiment of the present invention, Figure 14 is part I-I of Figure 13 is a cross section of

On the other hand, as shown in FIG. 8, the tunnel excavation apparatus for forming a free surface according to the present invention has a width direction such that a free surface Fs is simultaneously formed in a unit area Ku formed along a virtual excavation line K. A bit part 100 in which a plurality of punched bits 110 are arranged along (W), and a driving part 200 that provides a driving force to operate the bit part 100, the punched bit 110 includes, It may include a first bit 111 disposed in the front in the axial direction (A), and a second bit 112 disposed in the rear in the axial direction (A).

As described above, in the state in which the virtual excavation ship K and the excavation target space Ts are set, drilling is first carried out along the virtual excavation line K, and in this way, the free surface Fs is formed. When the target space (Ts) is blasted, vibration and noise are effectively prevented from being transmitted to the surroundings, and at the same time, the space for the excavation target space (Ts) to be expanded is secured during blasting, so that the excavation target space (Ts) can be easily destroyed. and rapid excavation is possible while removing it. At this time, in order to form the free surface Fs, the virtual excavation vessel K is first divided into n unit areas Ku (where n is an integer greater than or equal to 2), and when the excavation vessel K is divided, each unit The hole is drilled so that the free surface Fs is formed in the region Ku, but the free surface Fs in the unit region Ku is formed at the same time.

To this end, the bit unit 100 in which a plurality of punctured bits 110 are arranged is provided. It is preferable that the length of the perforated bit 110 in the width direction (W) formed while being provided in plurality along the width direction (W) corresponds to the length of the unit region (Ku). That is, it is configured to be able to adjust the number of punched bits 110 arranged in the width direction W in accordance with the formation length of the unit region Ku.

The punched bit 110 may include a first bit 111 disposed in the front in the axial direction (A), and a second bit 112 disposed in the rear in the axial direction (A). The first bit 111 is disposed in the front of the axial direction (A) and disposed at the reference position (P) to set the reference so that the drilling is made at an accurate position when the unit area (Ku) is drilled, and the second bit (112) punctures the unit area in a state in which the reference is set through the first bit 111 .

12 and 13, it includes a driving unit 200 that provides a driving force so that the bit unit 100 operates, and through the driving unit 200, each punched bit 110 is simultaneously or alternately action becomes possible. The order in which each drill bit 110 operates is adjustable according to the conditions of the tunnel excavation site.

A contact surface 111a supported in contact with the reference position P in the unit area Ku may be provided at the tip of the first bit 111 . That is, as the perforation of the unit area Ku proceeds in a state in which the contact surface 111a is contacted and supported at the reference position P, the perforation at the correct position is possible.

11 , the first bit 111 and the second bit 112 may be partially overlapped with each other in the width direction W. That is, the first bit 111 and the second bit 112 are configured to form a constant overlap length d along the width direction W. When configured in this way, the portion remaining while the first bit 111 is struck in advance is punctured while the second bit 112 is struck in a trailing manner, so that a continuous free surface Fs can be formed in the unit area Ku. .

As shown in FIG. 14 , the above-described driving unit 200 has a single driving motor 210 and a single driving shaft connected to the rotation shaft of the driving motor 210 so that driving force is simultaneously transmitted to the plurality of perforated bits 110 . (220) may be included. That is, since the plurality of perforation bits 110 are simultaneously operable through the single drive shaft 220 connected to the rotation shaft of the single drive motor 210, the overall configuration is simplified to reduce manufacturing costs, and the plurality of perforations A stable operation of the bit 110 is possible.

In this case, a separate reduction gear may be disposed between the rotation shaft of the driving motor 210 and the single driving shaft 220 . When the speed reducer is provided in this way, it is possible to reduce the rotation speed of the rotation shaft of the driving motor 210 and increase torque at the same time to secure a stable driving force for operating the driving shaft 220 .

14 , the drive shaft 220 is provided with a plurality of worms 221 corresponding to each of the drilling bits 110 , and the plurality of drilling bits 110 has a worm gear corresponding to the worm 221 . 120 may be provided, respectively. For example, the driving shaft 220 may include a first worm 221a at a position where the first bit 111 is disposed, and a second worm 221b at a position where the second bit 112 is disposed. there is. In addition, the first bit 111 is provided with a first worm gear 121 operating while meshing with the first worm 221a, and the second bit 112 has a second worm operating while meshing with the second worm 221b. A gear 122 may be provided.

In this case, the first worm 221a and the second worm 221b may have different gear ratios. That is, the first worm 221a operates the first worm gear 121 provided in the first bit 111 , and the second worm 221b is the second worm gear provided in the second bit 112 , respectively. 122 is operated, the first bit 111 is punctured while setting the reference position P in the unit area Ku, so the load is most likely to be applied, and thus the first bit 111 is It is configured to secure a large torque by setting the gear ratio low for operation. On the other hand, the second bit 112 has a relatively small load since the first bit 111 is punctured and the remaining part is punctured. It is possible to effectively shorten the drilling time of the unit area (Ku) by quickly drilling the remaining part. In this case, the first worm gear 121 and the second worm gear 122 may also have different gear ratios.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same spirit. , changes, deletions, additions, etc. may easily suggest other embodiments, but this will also fall within the scope of the present invention.

1: punching device 100: bit part
110: punched bit 111: first bit
111a: contact surface 112: second bit
120: worm gear 121: first worm gear
122: second worm gear 200: driving unit
210: drive motor 220: drive shaft
221: worm 221a: first worm
221b: second worm A: axial direction
W: Width direction d: Overlap length
Fs : Free side K : Excavation vessel
Ku : unit area Ku1 : first unit area
Ku2: second unit area P: reference position
Ts: Excavation target space

Claims (13)

forming a free surface while drilling along a virtual excavation ship; and
excavating after blasting the excavation target space surrounded by the free surface; includes,
The step of forming the free surface includes dividing the virtual excavation ship into n unit areas (n is an integer greater than or equal to 2), and drilling so that the free surface is simultaneously formed in the unit area,
The step of drilling so that the free surface is simultaneously formed in the unit area includes the step of drilling using a drilling device in which a plurality of drilling bits are arranged along the width direction,
The step of drilling using the drilling device includes: arranging a first bit disposed forward in the axial direction at a reference position within the unit area;
After disposing the first bit at the reference position, the step of hitting ahead so that the axial front part of the first bit is inserted into the reference position;
Checking whether the first bit has hit the regular position in advance after the step of hitting the front part of the first bit in the axial direction to be inserted into the reference position;
After the step of preceding hitting so that the axial front part of the first bit is inserted in the reference position, the step of hitting the second bit disposed at the rear in the axial direction is followed by hitting the unit area,
The step of drilling using the punching device includes the step of hitting the second bit after hitting the first bit in a state in which the first bit and the second bit are partially overlapped along the width direction and then hitting the first bit ,
and a single drive shaft connected to a rotation shaft of a drive motor so that a driving force is simultaneously transmitted to the first bit and the second bit, and the drive shaft includes a first worm meshing with a first worm gear provided in the first bit and a second worm engaged with a second worm gear provided on the second bit;
The gear ratio between the second worm and the second worm gear is the first worm and the first worm gear so that the rotation speed of the second bit for drilling the remaining part after the first bit is punctured is faster than the rotation speed of the first bit. A tunnel excavation method using a free surface that is set higher than the gear ratio between the two. According to claim 1,
The step of drilling so that the free surface is simultaneously formed in the unit area includes the steps of drilling so that the free surface is simultaneously formed in the first unit area, and sequentially such that the free surface is simultaneously formed in the second unit area adjacent to the first unit area A tunnel excavation method using a free surface comprising the step of drilling with a delete delete delete delete delete delete a bit portion in which a plurality of drilling bits are arranged along a width direction so that a free surface is simultaneously formed in a unit area formed along a virtual excavation ship; and
a driving unit providing a driving force to operate the bit unit; includes,
The punched bit includes a first bit disposed at the front in the axial direction and a second bit disposed at the rear in the axial direction,
The driving unit includes a single driving motor and a single driving shaft connected to the rotation shaft of the driving motor so that driving force is simultaneously transmitted to the plurality of perforated bits,
The drive shaft includes a first worm meshing with a first worm gear provided on the first bit, and a second worm meshing with a second worm gear provided on the second bit,
In a state in which the first bit and the second bit are partially overlapped along the width direction, the second bit disposed at the rear in the axial direction after the step of prior striking so that the axial front part of the first bit is inserted at the reference position Strikes trailing so that it is inserted into the unit area,
The gear ratio between the second worm and the second worm gear is such that the rotation speed of the second bit that strikes the second bit in the following way is faster than the rotation speed of the first bit that strikes the first bit so as to puncture the part remaining after the first bit is punctured. A tunnel excavation device for forming a free surface, which is set higher than the gear ratio between the and the first worm gear. 10. The method of claim 9,
A tunnel excavation apparatus for forming a free surface provided with a contact surface supported in contact with a reference position within the unit area at the tip of the first bit. delete delete delete

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