JPH09250289A - Excavating method for tunnel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the term of work and to improve economical efficiency by forming a horizontal or downward improved land forming body in a ground under a support leg part through a boring device prior to the forming of a forepile. SOLUTION: The drill guide 69 of a forepiling boring machine 83 is composed so as to be able to incline forward from a horizontal direction to a downward direction. Prior to the forming of a forepile, a ground under a support leg part is bored by a casing cutter 89 used combinedly for an injection pouring pipe connected to a boring device 67. Next the casing cutter 89 is rotated, and a hardening agent G is high-pressure jetted toward the side from an injection nozzle 93 attached to the tip of the casing with the casing moved longitudinally. The ground is thereby cut, mixed and agitated, and a horizontal or downward improved land forming body 101 is formed in the ground under the support leg part. Thus the reinforcement of the ground under the support leg part carried out by the excavating machine 83 becomes possible, and the shortening of the term of work and the improvement of economical efficiency can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for excavating a tunnel, and more specifically, an improvement of a conventionally known fore-pilling hole drilling machine, which enables reinforcement of a lower ground of a support leg by the fore-piling hole drilling machine. The present invention relates to a tunnel excavation method that shortens the construction period and improves the economical efficiency.

[0002]

2. Description of the Related Art In recent years, in the construction of tunnels, the construction of large-section tunnels has been increasing in the collapsible ground where structures are built on the top and the covering of the earth mass is thin. For this reason, as an auxiliary method for large-scale excavating machines, use a forepiling drilling machine before excavating a tunnel in order to prevent loosening of the ground at the time of excavation and to prevent face collapse and crown collapse. The front-end construction method that stabilizes the cutting face is widely adopted by forming a fore pile in an arch shape along the tunnel cross section in front of the cutting face.

FIGS. 15 to 18 show a method for forming a fore pile by the double rotary drilling device 1 shown in FIG. 19. The drilling device 1 shown in FIG. They are mounted on drill guides 9 and 11 supported by telescopic position rams 5 and 7, respectively. Then, an inner rod (inner tube) 19 having an inner bit 17 attached to the tip thereof is coaxially arranged inside a casing (reinforcing steel tube) 15 held by a rotary drive device 13 via a rotary striking device (hydraulic drifter) 21. Insert,
The injection nozzle 23 is held on the tip side of the inner rod 19, and the ring bit 25 is attached to the tip of the casing 15.

The formation of the fore pile by the hole making device 1 is performed by the two telescopic position rams 5, 5.
7 is appropriately expanded / contracted and rotated to determine the height direction of the drilling device 1, and further the position of the target ground wall surface is determined by the elevation angle and the lateral inclination, and then the inner rod 19 and the casing 1 are determined.
5 in the direction of the excavation of the pit, and by rotationally press-fitting it into the peripheral soil 29 of the soil 27 to be excavated as shown in FIG. The ground 29 of the part is primarily drilled up to the front of the improved forming part m in FIG.

After the completion of the primary drilling, the injection nozzle 23 mounted on the tip side of the inner bit 17 and the inner rod 19 is projected from the tip of the casing 15 as shown in FIG. When the casing 15 is rotationally press-fitted into the peripheral ground 29, the hardening material G is laterally injected at high pressure from the injection nozzle 23 to form a cylindrical solidified formation 31 in the improved formation portion m, and then as shown in FIG. By leaving the casing 15 in the ground and pulling out the inner rod 19, a fore pile 33 having the casing 15 as a core material is formed in the improved forming portion m. Then, as shown in FIG. 18, such a fore pile 3
After constructing the arch-shaped lining body 35 by sequentially adjoining 3 along the ground 27 to be excavated, the face inside the lining body 35 is excavated within the range of the length of the lining body 35 or less to support it. The tunnel is excavated by repeating the process of lining.

Incidentally, in FIG. 19, 37 is an earth swivel swivel and 39
Is a high pressure swivel. By the way, when excavating the ground as described above and installing support works to build a tunnel, when the ground is unconsolidated ground such as earth and sand or talus layer,
The ground arch of the ground is difficult to be formed, and the loosening load and uneven earth pressure due to tunnel excavation become large, and a large vertical force acts on the supporting leg. When the bearing capacity of the ground is insufficient, various problems occur, such as the subsidence of the entire support work, the deformation of the support work, and the subsidence of the ground.

[0007] Therefore, in order to prevent such a problem, various leg reinforcement works are being carried out today, one of which is the use of a special machine to attach a small diameter steel pipe and a steel pipe pile made of cement-based injection material to the leg. Like the micro-pile construction method that is built in and the AGP construction method that uses a general-purpose machine to build steel pipe piles with small diameter steel pipes and urethane-based injection materials in the legs, leg reinforcement work that strengthens the ground strength by improving the ground. It has been known.

The micropile method is used to prevent leg subsidence,
In order to stabilize the tunnel structure by increasing the ground bearing capacity and reinforcing the support work, steel pipe piles that are also used for injection are placed around the tunnel legs as described above. Drilling and steel pipe placement are performed with a dedicated machine. Therefore, various drilling methods such as down-the-hole hammer method, top hammer method, and rotary method can be selected according to the geological conditions, and it has a wide range of applicability from earth and sand ground to boulder gravel layer and cobblestone ground. There is.

[0009]

However, in the above-mentioned micropile construction method and AGP construction method, a special-purpose machine or a general-purpose machine is required, and the well-known fore-piring boring machine is a drill. In some cases, it is not possible to incline the guide downward in the direction of the ground below the supporting legs,
When the receiving method is constructed using the fore piling boring machine, these dedicated machines and general-purpose machines must be prepared separately from the fore piling boring machine, and these equipment and There was a problem to be solved, such as an increase in risk associated with parallel work with the hole drilling machine.

The present invention has been devised in view of the above circumstances, and an improvement has been made to a conventionally known fore piling boring machine,
An object of the present invention is to provide a tunnel excavation method capable of reinforcing the lower ground of a supporting leg by the forepiling boring machine, thereby shortening the construction period and improving the economical efficiency.

[0011]

In order to achieve such an object, the invention according to claim 1 is to extend and retract a telescopic position ram of a forepiling drilling machine,
After constructing an arch-shaped lining body by sequentially forming the fore piles along the ground to be excavated by the drilling device on the drill guide supported by the telescopic position ram, cover the inner face of the lining body. In the tunnel excavation method in which the tunnel is excavated by repeating the process of excavating in the range of the length of the body or less and performing support and lining, the drill guide of the fore-pilling boring machine from the horizontal direction. Configured so that it can lean forward in the downward direction, prior to the creation of the fore pile,
A feature of the present invention is that a drilling device attached to a drill guide creates a horizontal or downward improved structure on the lower ground of the support leg.

The invention according to claim 2 is based on claim 1.
In the method for excavating a tunnel described in the above, the improved structure has a casing that also serves as a jet injection pipe connected to a drilling device, drills the lower ground of the support leg and rotates the casing to move it backward or forward. Further, the invention is characterized in that a hardening material is laterally injected at high pressure from an injection nozzle attached to the tip side thereof, the ground is cut, and the mixture is mixed and agitated, and the invention according to claim 3 is In the tunnel excavation method according to Item 1, in the improved structure, a casing connected to a hole drilling device is used to drill the lower ground of a support leg and a jet injection pipe is newly added to the hole drilling device without the casing. After connecting and inserting this into the casing, after recovering the casing, rotate the injection injection pipe to move it backward or forward, and inject the curing material laterally at high pressure from the injection nozzle attached to the tip side. Cutting the ground and mixing It is characterized in that stirring to the reclamation.

(Operation) In the tunnel excavating method according to the first aspect of the present invention, prior to the formation of the fore pile, the drill guide is tilted forward from the horizontal direction to the downward direction, and is attached to the drill guide. As a result, the horizontal or downward improved structure is formed on the ground below the supporting leg.

According to a second aspect of the present invention, in the improved structure, the casing for the injection support pipe connected to the drilling device is used to drill the lower ground of the support leg, and then the casing is removed. It is rotated and moved backward or forward, and then a hardened material is laterally injected at a high pressure from an injection nozzle attached to the tip end side, the ground is cut, and the mixture is mixed and agitated.

Further, according to the excavating method of the third aspect of the present invention, in the improved structure, after the support foundation leg lower ground is drilled by the casing connected to the drilling device, it is injected into the drilling device without the casing. After newly connecting the injection pipe and inserting it into the casing, after recovering the casing, rotate the injection injection pipe to move it backward or forward, and set the hardened material side from the injection nozzle attached to the tip side. It is made by injecting high pressure to one side, cutting the ground, mixing and stirring.

The improved structure thus constructed reinforces the lower ground of the supporting leg to counter the vertical load and prevent the surface subsidence.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

1 to 4 show a forepiling drilling machine used in an embodiment of the invention according to claims 1 and 2, 41 in FIG. 1 is a base which can be self-propelled by a caterpillar 43, and 45. , 47 are rotary ring slide bases attached to the front and rear of the base 41. The rotary ring slide base 45 located in front of the base 41 has rotary rings 49, 51 on its front guide 45a and rear guide 45b.
Are mounted respectively, and the front and rear guides 47a, 47 of the rotary ring slide base 47 located on the rear side of the base 41 are mounted.
Rotation rings 53 and 55 are attached to the respective b, and the rotation rings 49, 51, 53 and 55 are attached to the guides 4 respectively.
The motors 5a, 45b, 47a, 47b move up and down in the direction of the arrow, and the motors 57 mounted on the respective units 5a, 45b, 47a, 47b can rotate in the direction of the arrow at a predetermined angle as shown in FIG.

Further, telescopic position rams 59, 61, 63 and 65, which are extendable and contractible in the axial direction, are attached to the rotary rings 49, 51, 53 and 55, respectively.
As shown in FIG. 2, each telescopic position ram 5
9, 61, 63, 65 are the rotary rings 49, 51, 5
A circular motion is made in the same direction as the rotation of 3,55 in the direction of the arrow. Then, as shown in FIGS. 1 to 4, one drill guide 69 equipped with a drilling device 67 is horizontally mounted between the tip of the telescopic position ram 59 and the tip of the telescopic position ram 63.
Further, between the tip of the telescopic position ram 61 and the tip of the telescopic position ram 65, one drill guide 71 equipped with a hole drilling device 67 is horizontally installed.

Then, as shown in FIGS. 3 and 4, the rotary rings 53 and 55 mounted on the rotary ring slide base 47 at the rear of the base 41 are slid upward (in the direction of arrow A in the figure), and By arranging the rotary rings 49 and 51 mounted on the rotary ring slide base 45 in front of the base 41 downward, the drill guides 69 and 71 can be respectively tilted forward from the horizontal direction to the downward direction. There is.

When forming the fore pile, the rotary rings 49, 51 mounted on the rotary ring slide base 45 are mounted.
Slide upward, and the rotary rings 53 and 55 mounted on the rear rotary ring slide base 47 are arranged downward so that the tip ends of the drill guides 69 and 71 are respectively tilted backward from the horizontal direction to the upward direction. Of course, it can be done.

The drilling device 67 moves on the drill guides 69 and 71 by wire feed, and, like the drilling device 1 shown in FIG. 19, comprises a rotary drive device 73 and a rotary impact device (hydraulic drifter) 75. Has been done. Then, when forming the fore pile, an inner rod (inner tube) having an inner bit attached to the tip thereof is coaxially moved through a rotary striking device 75 in a casing (reinforcing steel pipe) held by a rotary drive device 73. It is designed to be inserted and held.

For the construction of the fore pile by the boring device 67, first, as in the conventional example described in FIGS.
The height direction of the hole drilling device 67 is determined by expanding and contracting and rotating 63 and 65, and the position of the target ground wall surface is determined by the elevation angle and the left and right inclination, and then the inner rod and casing are excavated. Directionally press-fitted into the peripheral edge of the ground to be excavated, and the inner bit at the tip of the inner rod and the ring bit at the tip of the casing are used to perform primary drilling of the ground at the front surface of the bit to the front of the improved formation section.

After the completion of the primary drilling, the injection nozzle mounted on the tip side of the inner rod is made to project from the tip of the casing. In this state, the inner rod and the casing are rotationally press-fitted into the peripheral ground again, and then the injection nozzle is ejected. A forged pile with the casing as the core material is formed by injecting the hardened material to the side with high pressure to form a solidified solidified body in the improved formation part and then withdrawing the inner rod while leaving the casing in the ground. You can do it.

In addition, in FIG. 1, 77 and 79 are conventionally known rod guides, 81 is a clamp and joint breaker, and 82 is a winch which gives pushing force and pulling force to the boring device 67 during boring. The fore piling boring machine 83 used in the present embodiment is configured in this way, and one embodiment of the inventing method according to claims 1 and 2 is as follows using the fore piling boring machine 83. Be implemented.

First of all, as shown in FIG.
The fore piling boring machine 83 equipped with is driven to the front of the face 85a of the ground 85 to be excavated, and the rotary ring 4
By rotating 9, 51, 53, 55, the telescopic position rams 59, 61, 63, 65 are expanded and contracted, and the rotary ring 53 mounted on the rotary ring slide base 47 at the rear of the base 41 as shown in FIG. 55 is slid upward, and the rotary rings 49, 51 mounted on the rotary ring slide base 45 in front of the base 41 are arranged downward, and the drill guides 69, 71 are respectively directed toward the lower ground 87 of the support leg. Tilt forward downward.

Then, as shown in FIG. 6, a casing 89 is connected to the rotary striking device 75 of the hole drilling device 67, and the casing 89 is striking by the rotary striking device 75, and the casing 89 is rotated to rotate its tip. The well-known hole drilling bit 91 shown in FIG. 7 and FIG. 8 mounted on the base support leg lower ground 87 is drilled to a predetermined length. It should be noted that one of the drill guides 69 is shown in FIG. 5 and subsequent figures to describe the drilling of the support leg lower ground 87 and the formation of the fore pile by the drilling device 67 on the drill guide 69, but the other drill guide 69 will be described. The work by the drilling device 67 on the drill guide 71 is also performed simultaneously on the opposite side of the drill guide 69 with the base 41 interposed therebetween.

By the way, in this embodiment, the casing 8 is
9 is also used as an injection injection pipe of a hardening material (cement milk). Therefore, as shown in FIG. 7, the casing 8
An injection nozzle 93 for laterally injecting the hardened material at a high pressure is attached to the peripheral wall on the tip side of 9, and at the time of boring the lower support leg ground 87, a high pressure swivel (Fig. Drilling water pumped from (not shown) is jetted at high pressure in the drilling direction from the drilling water ejection hole 95 provided at the center of the drilling bit 91, and after the drilling is finished, the casing 8
The ball 97 thrown into the inside 9 closes the drilling water ejection hole 95 by the injection pressure of the hardening material. The slime is discharged to the outside from between the casing 89 and the boring hole 99.

After the boring of the support leg lower ground 87 is completed in this way, the ball 97 is put into the casing 89 to switch the boring water to the hardening material. Then, the ball 97 blocks the drilling water ejection hole 95 by the injection pressure of the hardening material.
As shown in FIG. 10, the hardening material G pressure-fed into the casing 89 is laterally high-pressure injected from the injection nozzle 93.

Therefore, as shown in FIG. 10, the casing 89 is rotated by the rotary striking device 75 to be retracted, and the injection nozzle 9 is
The supporting leg lower part ground 87 is cut with the hardening material G that is laterally injected at high pressure from 3 and mixed and stirred to form the columnar elongated improved structure 101 downward to the vicinity of the face 85a. Then, after the completion of the formation of the improved body 101, the casing 89 is pulled out, and as shown in FIG.
Fore pile 1 with casing (steel pipe for reinforcement) as core material
03 is sequentially formed adjacent to the ground 85 to be excavated to construct an arch-shaped lining body, and then a face 85a inside the lining body
Is excavated within the range of the length of the lining body, and the support 105 is sequentially installed on the improved structure 101 as shown in FIG. 12, and the improved structure 101 is formed by repeating the steps as described above. You can do support and excavate the tunnel.

Thus, the improved construction body 101 reinforces the support leg lower ground 87 to counter the vertical load and prevent ground subsidence. Thus, the present embodiment is
By adding an improvement to the conventionally known fore piling boring machine, the lower ground 8 of the supporting leg by the fore piling boring machine 83
Since it is possible to reinforce No. 7, it becomes unnecessary to use a dedicated machine or a general-purpose machine in the conventional micropile construction method and AGP construction method. As a result, according to the present embodiment, these equipments and the fore piling boring machine 83 In addition to eliminating the risk associated with parallel work, it is possible to shorten the construction period and improve the economy as compared with the conventional examples using the micropile construction method or AGP construction method.

In the above embodiment, the improved construction body 10 is formed by using the casing 89 also serving as the injection and injection pipe shown in FIG.
1 was created, but instead of such a method, as in the excavation method according to claims 1 and 3, the fore piling boring machine 83 is used to firstly use a conventionally known casing for creating a fore pile. The rotating device 7 of the boring device 67
After drilling the support leg lower ground 87 with the drill bit attached to the tip of the casing, and after removing the casing from the drilling device 67 by clamping with the clamp and the joint breaker 81. , FIG. 13 and FIG.
As shown in FIG. 4, the injection injection pipe 109 having the injection nozzle 107 attached to the peripheral wall on the tip side is connected to the rotary impact device 75 side and inserted into the casing, and after the casing is recovered,
Rotate the injection injection pipe 109 to retract it,
The improved structural body 101 may be formed by laterally high-pressure injecting a hardening material from the injection nozzle 109 to cut the support leg lower ground 87 and mix and stir.

Thus, according to such an embodiment, the intended purpose can be achieved as in the above embodiment. Further, in each of the above-described embodiments, the improved structure 101 is formed by rotating the casing 89 also serving as the injection injection pipe and the injection injection pipe 109 and retracting the casing 89. In the method of the invention of Item 2, the casing 89 is once returned, and in the method of the invention of Claims 1 and 3, after the casing is recovered, the casing 89 and the injection injection pipe 109 are respectively rotated and moved forward. It is also possible to create the improved structure 101.

[0034]

As described above, according to the method of excavating a tunnel according to each of the claims, since it is possible to reinforce the lower ground of the supporting leg by the fore-pilling boring machine, the conventional micropile method is used. A dedicated machine or general-purpose machine in the AGP method is unnecessary, and as a result, the risk of parallel work between these equipment and the fore piling drilling machine is eliminated, and the construction period is shortened compared to the conventional one. Economic efficiency has been improved.

[Brief description of drawings]

FIG. 1 is a side view of a forepiling drilling machine used in an embodiment of the invention according to claims 1 and 2. FIG.

2 is a front view of the forepiling drilling machine shown in FIG. 1. FIG.

FIG. 3 is a side view of a forepiling drilling machine with a tilted drill guide.

4 is a front view of the forepiling drilling machine shown in FIG. 3. FIG.

FIG. 5 is a process explanatory view of an embodiment of the tunnel excavation method according to claims 1 and 2;

FIG. 6 is a process explanatory view of an embodiment of the tunnel excavation method according to claims 1 and 2;

FIG. 7 is a sectional view of the tip side of the casing used in the embodiment of the tunnel excavating method according to the first and second aspects.

FIG. 8 is a front view of the drill bit attached to the tip of the casing.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 7;

FIG. 10 is a process explanatory view of an embodiment of the tunnel excavation method according to claims 1 and 2;

FIG. 11 is a process explanatory view of an embodiment of the tunnel excavation method according to claims 1 and 2;

FIG. 12 is a process explanatory diagram of an embodiment of the tunnel excavation method according to claims 1 and 2;

FIG. 13 is a sectional view of a tip end side of a jet injection pipe used in an embodiment of a tunnel excavating method according to claims 1 and 3;

14 is a sectional view taken along line XIII-XIII in FIG.

FIG. 15 is a cross-sectional view of the ground to be excavated and its peripheral ground.

FIG. 16 is an explanatory view showing a conventional fore pile forming method.

FIG. 17 is a cross-sectional view of a fore pile in the ground.

FIG. 18 is a transverse cross-sectional view of a tunnel having a fore pile lining body formed therein.

FIG. 19 is a side view of a conventional drilling device.

FIG. 20 is an overall side view of a conventional forepiling boring machine.

[Explanation of symbols]

41 base 45,47 rotating ring slide base 49,51,53,55 rotating ring 57 motor 59,61,63,65 telescopic position ram 67 drilling device 69,71 drill guide 83 fore piling drilling machine 85 ground to be excavated 85a Face 87 Support lower leg ground 89 Casing 91 Drilling bit 93,107 Injection nozzle 99 Boring hole 101 Improved structure 103 Fore pile 105 Supporting 109 Injection injection pipe G Hardening material

Claims (3)

[Claims] 1. A telescopic position ram of a fore piling boring machine is expanded / contracted and rotated to sequentially adjoin the fore piles along a ground to be excavated by a boring device on a drill guide supported by the telescopic position ram. After constructing the arch-shaped lining body, repeat the process of excavating the inside face of the lining body within the range of the length of the lining body and performing support lining, and excavating the tunnel. In the method of excavating a tunnel, the drill guide of the forepiling drilling machine is configured so that it can be tilted forward from the horizontal direction to the downward direction, and prior to the creation of the fore pile, by the drilling device attached to the drill guide,
A method for excavating a tunnel, characterized in that a horizontal or downward improved structure is formed in the ground below the supporting legs. 2. The improved structure is such that a casing which also serves as an injection pipe connected to a drilling device is used to drill the lower ground of a support leg and the casing is rotated to move it backward or forward, and the tip thereof. The tunnel excavation method according to claim 1, wherein the hardening material is laterally injected at a high pressure from an injection nozzle mounted on the side, the ground is cut, and the mixture is mixed and agitated. 3. The improved structure is such that a casing connected to a hole drilling device is used to drill the lower ground of a support leg and a jet injection pipe is newly connected to the hole drilling device without the casing, and the injection pipe is connected to the inside of the casing. After recovering the casing, rotate the injection injection pipe to move it backward or forward, then inject the hardening material laterally from the injection nozzle attached to the tip side to cut the ground and mix it. The method for excavating a tunnel according to claim 1, wherein the method is performed by stirring.