JP7303756B2 - Open shield machine and tunnel construction method - Google Patents

Description

The present invention relates to open shield machines and methods of constructing tunnels using open shield machines.

Patent Literature 1 discloses a method of burying circular underdrains such as small-scale sewer pipes using an open shield machine. In Patent Document 1, an excavator (heavy equipment) such as a power shovel placed on the ground excavates a rock in front of an open shield machine.

Japanese Patent No. 2761516

However, since the technology disclosed in Patent Document 1 is for burying a small-scale culvert near the ground, the depth that can be excavated by an excavator is shallow, and it does not pay attention to the groundwater level of the surrounding ground. . Therefore, it was not suitable for constructing large-diameter tunnels such as road tunnels underground.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an open shield machine that can be used for constructing large-diameter tunnels.

Therefore, the open shield machine according to the present invention includes a box-shaped main body having a bulkhead on the front, a first opening on the top, and a second opening on the bottom of the rear, and A propulsion jack provided to propel the main body forward, an excavator for forming an excavated trench in the ground ahead of the main body, and a mud discharge means for discharging mud in the excavated trench to the outside of the excavated trench. . The mud discharge means includes a mud discharge opening formed through the bulkhead. Here, the bulkhead has a rectangular shape with a bottom semicircle connected to the bottom end of a vertically extending rectangle when viewed from the front.

A tunnel construction method according to the present invention is a method for constructing a tunnel using the above-described open shield machine. A tunnel construction method according to the present invention includes forming an excavated trench by excavating mud ahead of a bulkhead with an excavator.

According to the present invention, the mud discharge means for discharging the mud in the excavated trench to the outside of the excavated trench includes the mud discharge port penetrating the bulkhead. Therefore, when the main body of the open shield machine is moved forward after the ground ahead of the bulkhead is excavated with mud to form an excavated trench, the mud in the excavated trench is discharged through the aforementioned mud discharge port into the open shield machine. It can be discharged into the body (that is, out of the trench). Therefore, it is possible to form an excavation trench of a size suitable for a large-diameter open shield machine by mud excavation, and to advance the open shield machine while maintaining the water level of the mud in the excavation trench at a desired height. Therefore, it is possible to construct a large-diameter tunnel using the open shield machine.

BRIEF DESCRIPTION OF THE DRAWINGS Longitudinal view of the open shield machine in 1st Embodiment of this invention AA sectional view of FIG. BB arrow view and CC arrow view of the open shield machine in FIG. Rear view of the open shield machine in the first embodiment The figure which shows the tunnel construction method in the said 1st Embodiment. The figure which shows the tunnel construction method in the said 1st Embodiment. The figure which shows the tunnel construction method in the said 1st Embodiment. The figure which shows the tunnel construction method in the said 1st Embodiment. The figure which shows the tunnel construction method in the said 1st Embodiment. A diagram showing an example of an excavation pattern of excavation inside the cutting edge according to the first embodiment. A diagram showing an example of an excavation pattern of excavation inside the cutting edge according to the first embodiment. Diagram showing the starting situation of the sealed shield machine Figure showing the arrival status of the closed shield machine A diagram showing a tunnel building method according to the second embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an open shield machine 1 according to a first embodiment of the invention. FIG. 2 is a cross-sectional view taken along line AA of FIG. FIG. 3(a) is a BB arrow view of the open shield machine 1 in FIG. FIG. 3(a) is a CC arrow view of the open shield machine 1 in FIG. FIG. 4 is a rear view of the open shield machine 1. FIG. Here, FIGS. 1 to 3 show a state in which a ground (ground) G is excavated with mud water to form an excavated trench 30 by an excavator 4. As shown in FIG. On the other hand, FIG. 4 shows a state in which the excavator 4 is lifted from the excavated trench 30 to the ground. In this embodiment, for the sake of convenience, the front, rear, right, and left directions are defined with the tunnel construction advancing direction as the advancing direction.

The open shield machine 1 in this embodiment can be used, for example, for constructing large-diameter tunnels such as road tunnels. The open shield machine 1 includes a box-shaped main body 2 , a cylindrical skin plate 3 , an excavator 4 , mud supply means 5 and mud discharge means 6 .

The main body 2 has a rectangular shape surrounded by a front surface 2a, a rear surface 2b, a left side 2c, and a right side 2d when viewed from above. The front surface 2a (and the rear surface 2b) of the main body 2 has a shape in which a semicircle is connected to the lower end of a vertically extending rectangle (rectangular shape with a semicircle at the lower end).

A front surface 2 a of the body portion 2 is configured by a bulkhead (shield partition) 10 . A rear surface 2 b of the body portion 2 is configured by a rear plate 12 . A left side surface 2 c of the body portion 2 is configured by a left side plate 13 . A right side surface 2 d of the body portion 2 is configured by a right side plate 14 . The left side surface 2c and the right side surface 2d (the left side plate 13 and the right side plate 14) of the main body 2 are respectively extended rearwardly from the rear surface 2b (the rear plate 12) and extend surfaces 2ce and 2de (extended portions 13e and 14e). ).

The curved surface 2e of the main body 2 is curved in a downwardly convex semicircular shape, the upper left end portion is connected to the lower end portion of the left side surface 2c, and the upper right end portion is connected to the lower end portion of the right side surface 2d. there is A curved surface 2e of the main body 2 is formed by a lower plate 15 curved in a downwardly convex semicircular shape.

Of the edges of the front surface 10a of the bulkhead 10, portions other than the upper edge (that is, both the left and right edges and the lower edge) are provided with a cutting edge 16 extending in a U shape when viewed from the front. The cutting edge 16 has a sharp tip (front end). The cutting edge 16 has a friction cut (stepped portion) 17 for reducing the peripheral surface resistance of the open shield machine 1 .

The body portion 2 has a first opening 21 on its upper surface 2f. The first opening 21 has a rectangular shape when viewed from above, and includes an upper edge portion of the front surface 2a (bulkhead 10), an upper edge portion of the rear surface 2b (rear plate 12), and a left side surface 2c (left side plate 13). It is surrounded by the upper edge and the upper edge of the right side 2d (right side plate 14).

The body portion 2 has a second opening 22 at the bottom of the rear surface 2b (rear plate 12). The second opening 22 is circular in rear view. The inner diameter of the second opening 22 is larger than the outer diameter of the ring-shaped structure 40 to be described later, and is substantially equal to the inner diameter of the skin plate 3 .

The skin plate 3 has a cylindrical shape extending in the front-rear direction, and its front end is connected to the second opening 22 of the rear surface 2b (rear plate 12) of the main body 2. As shown in FIG. That is, the skin plate 3 is connected to the second opening 22 of the rear surface 2b (rear plate 12) of the main body 2 and extends rearward. A plurality of rows of tail seals 3 b extending in the circumferential direction along the rear edge of the skin plate 3 are provided on the inner peripheral surface of the tail portion 3 a of the skin plate 3 .

The tail seal 3b is, for example, a metal brush (wire brush). Incidentally, the tail seal 3b is not limited to being made of metal, and may be made of resin such as urethane.
The tail seal 3 b closes the gap between the inner peripheral surface of the tail portion 3 a of the skin plate 3 and the outer peripheral surface of the ring-shaped structure 40 . A filler such as grease may be filled in the gap between the tail seals 3b.

A plurality of propelling jacks 7 for propelling the main body 2 forward are provided inside the main body 2 . A plurality of propelling jacks 7 are circumferentially spaced from each other along the inner peripheral surface of the skin plate 3 inside the skin plate 3 when viewed from the rear of the open shield machine 1 . The propulsion jack 7 is telescopic in the front-rear direction. The propulsion jack 7 has a front end portion fixed to the main body portion 2 and a rear end portion capable of coming into contact with the existing ring-shaped structure 40 .

The propulsion jack 7 is a hydraulic jack composed of a cylinder 7a and a rod 7b. The front end portion of the cylinder 7a is fixed to the main body portion 2, and the rod 7b can be advanced and retracted at the rear end portion side. The propulsion jack 7 is extended while the rear end of the rod 7b of the propulsion jack 7 is in contact with the existing ring-shaped structure 40, whereby the open shield machine 1 including the main body 2 obtains propulsion force. can be done. In this way, the propelling jack 7 takes reaction force from the existing ring-shaped structure 40 to propel the open shield machine 1 .

An upper frame 25 is provided on the front upper portion of the main body 2 . A winch 26 that is an example of a lifting device is provided on the upper frame 25 . The winch 26 is configured to be movable in the left-right direction relative to the upper mount 25 on the upper mount 25 (see FIGS. 10 and 11, which will be described later).

The excavator 4 is suspended by a winch 26 via wires 27 . Here, the aforementioned lifting device lifts the excavator 4 . The lifting device described above moves the excavator 4 along the front surface 2a (bulkhead 10) of the main body 2. As shown in FIG.

In this embodiment, the winch 26 provided on the upper frame 25 will be described as an example of the lifting device, but the lifting device is not limited to this. For example, the aforementioned lifting device may be a portal crane installed on the ground or a mobile crane that can travel on the ground. In other words, the lifting device described above is not limited to being provided integrally with the body portion 2, and may be provided separately from the body portion 2. FIG.

The excavator 4 forms an excavated groove 30 in the natural ground G by muddy excavating (excavating in muddy water) the natural ground G in front of the front surface 2 a (bulkhead 10 ) of the main body 2 . In this embodiment, the excavator 4 excavates the inside of the U-shaped cutting edge 16 . In this embodiment, the length of the excavated groove 30 in the front-rear direction is about one ring of the ring-shaped structure 40 .

As the excavator 4, for example, an excavator used when constructing a diaphragm wall can be used. In this embodiment, as the excavator 4, a horizontal multi-axis rotary cutter type (so-called rotary type) excavator is illustrated. A bucket-type excavator may also be used. Further, in the present embodiment, an example in which the excavator 4 is provided with a horizontal four-axis drum cutter 4a is shown, but in addition, for example, the excavator 4 may be provided with a horizontal two-axis drum cutter 4a. . The excavator 4 has a drive (not shown) that rotates the drum cutter 4a.

A front surface 10a of the bulkhead 10 is provided with a plurality of guide rails 31 extending in the vertical direction, and guide rails 32 extending in a U shape so as to surround the guide rails 31 from the left, right and bottom sides. Here, the guide rails 31 and 32 guide the movement of the excavator 4 . The excavator 4 is configured to move along the guide rails 31 and 32 while holding the guide rails 31 and 32 . Further, the guide rails 31 and 32 are bulk-mounted so that the ground G (within the cutting edge 16) in front of the bulkhead 10 can be evenly excavated by moving the excavator 4 along the guide rails 31 and 32. It is provided on the front surface 10 a of the head 10 .

In this embodiment, while the excavator 4 is gripped by the guide rail 31, the wire winding and feeding operations of the winch 26 move the excavator 4 along the guide rail 31 while the excavator 4 moves the cutting edge. 16 can be excavated. Further, in this embodiment, the excavator 4 is moved along the guide rail 32 by the wire winding/feeding operation of the winch 26 and the lateral movement of the winch 26 itself in a state where the excavator 4 is gripped by the guide rail 32 . The inside of the cutting edge 16 can be excavated by the excavator 4 while moving the cutting edge 16 by the excavator. In this embodiment, since the excavator 4 grips the guide rails 31 and 32, the inside of the cutting edge 16 can be accurately excavated even when excavating with a slight longitudinal gradient.

The mud supply means 5 realizes the function of supplying mud into the excavated trench 30 . Further, the mud supply means 5 realizes the function of supplying mud for the aforementioned mud excavation. The mud supply means 5 includes a mud supply pipe (mud feed pipe) 35 . The mud supply pipe 35 is connected to a mud treatment plant (not shown) installed on the ground. A mud pump (not shown) is interposed in the middle of the mud supply pipe 35 .

The mud discharge means 6 realizes the function of discharging the mud in the excavated trench 30 to the outside of the excavated trench 30 . Further, the mud discharge means 6 also realizes a function of discharging the excavated earth and sand out of the excavated groove 30 together with the mud in the excavated groove 30 .

The mud discharge means 6 includes a plurality of mud discharge ports (sludge discharge ports) 36 formed through the bulkhead 10, a mud discharge pipe (sludge discharge pipe) 37 through which the mud flows from the mud discharge ports 36, and a mud discharge. and a plurality of on-off valves 38 for opening and closing the pipe 37 .

The mud discharge port 36 is a through hole formed in the bulkhead 10 . The muddy water discharge pipe 37 is connected from the rear surface of the bulkhead 10 through the inside of the main body 2 to the aforementioned muddy water treatment plant. A mud discharge pump (not shown) is interposed in the middle of the mud discharge pipe 37 .

The aforementioned mud treatment plant adjusts the mud to a predetermined concentration. The mud whose concentration has been adjusted can be pressurized by the above-described mud pump and supplied into the excavated trench 30 in front of the bulkhead 10 through the mud supply pipe 35 . In the excavated trench 30, the drum cutter 4a of the excavator 4 rotates, for example, to mix the muddy water and the excavated earth and sand. Mud water mixed with excavated earth and sand in the excavated trench 30 is sucked by the above-described mud discharge pump and sent to the above-described mud water treatment plant through the mud water discharge port 36 and the mud water discharge pipe 37 . In the muddy water treatment plant, muddy water is separated from earth and sand, and the separated muddy water is adjusted to a predetermined concentration. On the other hand, the separated earth and sand are temporarily stored in an earth and sand pit (not shown).

In this embodiment, the upstream portion 37a of the muddy water discharge pipe 37 is branched so as to correspond to each of the plurality of muddy water discharge ports 36, and an on-off valve 38 is provided in each of the branched upstream portions 37a. That is, the on-off valve 38 is provided so as to correspond to each of the plurality of muddy water discharge ports 36 , and opening and closing of each muddy water discharge port 36 can be individually controlled by opening and closing each of the on-off valves 38 . Here, in this embodiment, the on-off valve 38 is an electromagnetic valve.

In this embodiment, opening and closing of each on-off valve 38 can be adjusted so that the water level WL2 of muddy water in the excavated trench 30 is higher than the groundwater level WL1 of the surrounding natural ground G.

The left side plate 13 resists earth and water pressure from the left side. The extended portion 13e of the left side plate 13 serves as an earth retaining wall for a portion that temporarily collapses as the open shield machine 1 advances (see gap C in FIG. 7(a), which will be described later).

The right side plate 14 resists earth and water pressure from the right side. The extended portion 14e of the right side plate 14 serves as a retaining wall for a portion that temporarily collapses as the open shield machine 1 advances (see gap C in FIG. 7(a), which will be described later).

The rear plate 12 resists earth and water pressure from behind. Further, the rear plate 12 absorbs the reaction force when the thrust jack 7 is unloaded when the ring-shaped structure 40 is inserted into the main body 2 (see FIGS. 8A and 8B described later). It also has the purpose of taking from the natural ground G.

Next, a method of constructing the tunnel 41 using the open shield machine 1 will be described using FIGS. 5 to 9 in addition to FIGS. 1 to 4 described above. 5 to 9 show the construction method of the tunnel 41 in this embodiment. Here, FIG. 5(a) is a cross-sectional view taken along line DD of FIG. 5(b). FIG. 6(a) is a cross-sectional view taken along line EE of FIG. 6(b). FIG. 7(a) is a cross-sectional view taken along line FF of FIG. 7(b). FIG. 8(a) is a cross-sectional view taken along line GG of FIG. 8(b). FIG. 9(a) is a cross-sectional view taken along the line HH of FIG. 9(b).

The tunnel 41 constructed in this embodiment is formed by sequentially connecting ring-shaped structures 40 having a circular cross section in the axial direction of the tunnel (tunnel construction progress direction). That is, the tunnel 41 includes a plurality of ring-shaped structures 40 connected in the axial direction of the tunnel. The ring-shaped structure 40 is formed by connecting a plurality of arcuate segments in the circumferential direction. This segment is precast concrete sized to be transportable by a transport vehicle. In this embodiment, the work of assembling the ring-shaped structure 40 (the work of connecting the segments) is performed on the ground.

In the construction method of the tunnel 41 according to the present embodiment, first, as shown in FIGS. 5A and 5B and FIGS. , an excavated groove 30 is formed in front of the bulkhead 10 . Here, FIGS. 5A and 5B show the initial state of excavation inside the cutting edge 16 by the excavator 4, and FIGS. shows the state of the final stage of excavation. Excavated earth and sand generated by mud excavation by the excavator 4 is discharged from a mud discharge port 36 provided in the bulkhead 10 to a mud discharge pipe 37 . At the same time, by supplying mud into the excavated groove 30 from the mud supply pipe 35, the water level WL2 of the mud, which is a stable liquid in the excavated groove 30, is maintained above the level at which the wall surface of the face is not collapsed. Each on-off valve 38 opens and closes in conjunction with movement of the excavator 4 . Specifically, for example, only the on-off valve 38 corresponding to the mud discharge port 36 located near or slightly above the location where excavated soil is generated by the excavator 4 is opened to drain the mud. By supplying mud from the mud supply pipe 35 into the excavated trench 30 accordingly, the water level WL2 of the mud in the excavated trench 30 is maintained as described above. By doing so, efficient sludge can be discharged.

10 and 11 show an example of an excavation pattern for excavation inside the cutting edge 16 in this embodiment. 10 and 11, illustration of the muddy water level WL2 in the excavated trench 30 is omitted. 10 and 11, muddy water excavation is performed by the excavator 4 in the order of (a) to (h) in FIG. 10 and FIG. The excavation pattern for excavating inside the cutting edge 16 is not limited to that shown in FIGS. 10 and 11 .

Next, as shown in FIGS. 7A and 7B, the excavator 4 is lifted from the excavated trench 30 to the ground by the winch 26 via the wire 27 . Then, the propelling jack 7 is extended to take a reaction force from the existing ring-shaped structure 40 to move the open shield machine 1 forward. During this forward movement, all the on-off valves 38 are opened, and the muddy water level WL2 in the excavated trench 30 is maintained while the muddy water is discharged as a whole. In this way, when the open shield machine 1 moves forward, all the on-off valves 38 are opened to perform overall mud discharge, so that the bulkhead 10 receives muddy water in the excavation trench 30 when the open shield machine 1 moves forward. Resistance can be reduced. As the open shield machine 1 advances, the cutting edge 16 penetrates the ground G ahead. At the same time, since a gap C is formed behind the rear plate 12, the gap C is quickly backfilled using a heavy machine such as a backhoe. For this backfilling, sediment separated by the aforementioned mud treatment plant may be used.

After advancing the open shield machine 1 by a predetermined distance, all the on-off valves 38 are closed. Then, as shown in FIGS. 8(a) and 8(b), the above-mentioned backfilling soil is surely compacted to ensure passive resistance. After that, the propulsion jack 7 is shortened, and the new ring-shaped structure 40 assembled on the ground is inserted into the main body 2 from the first opening 21 of the upper surface 2f of the main body 2, and the existing ring-shaped structure 40 and the shortened propulsion jack 7. A gate-type crane installed on the ground, a mobile crane that can travel on the ground, or the like can be used for inserting and arranging the newly-installed ring-shaped structure 40 .

Next, as shown in FIGS. 9A and 9B, the newly installed ring-shaped structure 40 is joined to the existing ring-shaped structure 40, and the propelling jack 7 is extended to fix the open shield machine 1. . After that, the inside of the cutting edge 16 is excavated as described above. By repeating the steps shown in FIGS. 5 to 9 in this way, the tunnel 41 is constructed in the ground.

According to the construction method shown in this embodiment, it is possible to mechanically excavate a shallow tunnel, for which an open-cut method has been adopted so far, without performing earth retaining excavation. By using the ring-shaped structure 40, the construction period can be greatly shortened and the construction cost can be greatly reduced. In addition, since the on-site work is greatly simplified, it will be possible to cope with future labor shortages, and the amount of excavation will be reduced compared to the open-cut method, so the surplus soil disposal cost will also be reduced.

In addition, when constructing a section from the ground to the underground, such as a road tunnel, when constructing a section until the earth covering necessary for the shield construction method can be secured, it is slightly larger than the shield tunnel constructed by the shield construction method. By constructing the tunnel using the open shield machine 1 and improving the ground on the front side, it is possible to start and reach the closed shield machine, and in addition, it is possible to omit the construction of the starting shaft and the reaching shaft. . This point will be described with reference to FIGS. 12 and 13. FIG.

12A and 12B are diagrams showing the starting state of the enclosed shield machine 50. FIG. Specifically, FIG. 12(a) shows a state in which a tunnel 51 functioning as a starting base for the closed shield machine 50 is constructed using the open shield machine 1. FIG. FIG. 12(a) shows the closed shield machine 50 starting from the tunnel 51 functioning as the starting base.

12A and 12B show construction of a tunnel 51 that is slightly larger than the shield tunnel 52 using the open shield machine 1, and construction of start protection work (ground improvement work) 54 on the front. ing. The tunnel 51 extends obliquely downward from the ground. After cutting the bulkhead 10, the enclosed shield machine 50 starts from a tunnel 51 which is a starting base.

Here, the closed shield machine 50 includes, for example, a cylindrical skin plate 50a that forms the outer shell of the machine body, and a front end (face side end) of the skin plate 50a that protects the natural ground G. It comprises a cutter head 50b for excavating and a propulsion jack 50c provided inside the skin plate 50a. In the shield construction method using the closed shield machine 50, while excavating the ground G with the closed shield machine 50, an erector device (not shown) is used inside the rear portion (tail portion) of the skin plate 50a. The segment rings 50d are constructed by assembling the segment pieces one after another in the tunnel circumferential direction, and the shield tunnel 52 is constructed by connecting the adjacent segment rings 50d in the tunnel axial direction. In the shield construction method, the closed shield excavator 50 pushes the existing segment ring 50d behind it backward with the propulsion jack 50c, and moves forward while excavating the natural ground G by thrust generated as a reaction force.

FIG. 13 is a diagram showing the arrival state of the enclosed shield machine 50. As shown in FIG. Specifically, FIG. 13A shows a state in which a tunnel 56 functioning as an arrival base for the closed shield machine 50 is constructed using the open shield machine 1 . FIG. 13(a) shows a state in which the enclosed shield machine 50 has reached the tunnel 56 functioning as the arrival base.

FIGS. 13A and 13B show construction of a tunnel 56 that is slightly larger than the shield tunnel 52 using the open shield machine 1, and construction of an arrival protection work (soil improvement work) 57 on the front. ing. The tunnel 56 extends obliquely downward from the ground. After cutting the bulkhead 10, the enclosed shield machine 50 reaches the tunnel 56 which is the arrival base.

According to this embodiment, the open shield machine 1 is a box having a bulkhead 10 on the front surface 2a, a first opening 21 on the top surface 2f, and a second opening 22 on the bottom of the rear surface 2b. a body portion 2 having a shape, a propulsion jack 7 provided in the body portion 2 to propel the body portion 2 forward, an excavator 4 for forming an excavation groove 30 in the ground G ahead of the body portion 2, and an excavation groove and a mud discharge means 6 for discharging the mud in the excavated trench 30 to the outside. The mud discharge means 6 includes a mud discharge port 36 formed through the bulkhead 10 . Therefore, when the main body 2 of the open shield machine 1 is moved forward after muddy excavating the natural ground G ahead of the bulkhead 10 to form the excavated groove 30, the mud in the excavated groove 30 is discharged through the mud discharge port 36. can be discharged into the main body 2 of the open shield machine 1 (that is, outside the excavated trench 30). Therefore, the excavation groove 30 having a size suitable for the large-diameter open shield machine 1 can be formed by muddy water excavation, and the open shield machine 1 can maintain the muddy water level in the excavation groove 30 at a desired height. can be advanced, the open shield machine 1 can be used to construct large-diameter tunnels 41, 51, 56.

According to this embodiment, the bulkhead 10 also includes guide rails 31 and 32 that guide the movement of the excavator 4 . As a result, the inside of the cutting edge 16 can be excavated with high accuracy using the excavator 4 .

Further, according to the present embodiment, the open shield machine 1 includes the cylindrical skin plate 3 connected to the second opening 22 and extending rearward, and the skin plate 3 provided on the inner peripheral surface of the skin plate 3 and extending behind the skin plate 3 . and a tail seal 3b extending along the edge. The tail seal 3 b can close the gap between the inner peripheral surface of the skin plate 3 and the outer peripheral surface of the existing ring-shaped structure 40 .

Further, according to this embodiment, the excavator 4 can be lifted and lowered by being suspended by a lifting device (for example, the winch 26). This lifting device may be directly or indirectly attached to the main body 2 like the winch 26 described above, or may be a portal crane installed on the ground, or a crane traveling on the ground. It may also be located on the ground, such as possible mobile cranes.

Further, according to the present embodiment, the main body 2 has a rectangular shape surrounded by a front surface 2a, a rear surface 2b, and two side surfaces (a left side surface 2c and a right side surface 2d) when viewed from above. The two side surfaces (left side surface 2c, right side surface 2d) have extension surfaces 2ce, 2de that extend rearward from the rear surface 2b. These extended surfaces 2ce and 2de can serve as earth retaining walls for portions that temporarily collapse as the open shield machine 1 advances (see gap C in FIG. 7(a)).

Further, according to the present embodiment, the open shield machine 1 further includes a mud supply means 5 for supplying mud into the excavated trench 30 . The muddy water supply pipe 35 constituting the muddy water supply means 5 is preferably provided at a position that does not interfere with the forward movement of the body portion 2 . In this regard, in the present embodiment, the outlet 35a of the muddy water supply pipe 35 is located near the upper end of the front surface 2a of the main body 2 (the front surface 10a of the bulkhead 10) and opens downward.

Further, according to the present embodiment, the method of constructing the tunnels 41, 51, 56 using the open shield machine 1 is to excavate the ground G ahead of the bulkhead 10 with mud water using the excavator 4, thereby forming the excavated trench 30. Including forming. As a result, the excavated groove 30 having a size suitable for the large-diameter open shield machine 1 can be formed by mud excavation.

According to this embodiment, the mud discharge means 6 further includes a mud discharge pipe 37 through which mud flows from the mud discharge port 36 and an on-off valve 38 for opening and closing the mud discharge pipe 37 . The method of constructing the tunnels 41 , 51 , 56 using the open shield machine 1 further includes opening the on-off valve 38 when the main body 2 is advanced by the propulsion jack 7 . As a result, the resistance that the bulkhead 10 receives from the muddy water in the excavation trench 30 when the open shield machine 1 moves forward can be reduced.

Further, according to the present embodiment, the method for constructing the tunnels 41, 51, 56 using the open shield machine 1 is to excavate the tunnels 41, 51, 56 using a lifting device (for example, the winch 26) prior to the advance of the main body 2 by the propulsion jack 7. It further includes raising the machine 4 from within the excavated trench 30 to the ground. Therefore, the excavator 4 does not interfere with the forward movement of the main body 2 by the propulsion jack 7 .

Further, according to the present embodiment, the method for constructing the tunnels 41, 51, 56 using the open shield machine 1 is such that when the main body 2 is advanced by the propulsion jack 7, there is a gap between the rear surface 2b of the main body 2 and the natural ground G. backfilling the gap C formed in the . Passive resistance can be ensured by firmly compacting this backfill soil.

Further, according to the present embodiment, the method for constructing the tunnels 41, 51, 56 using the open shield machine 1 is to place the ring-shaped structure 40 constituting the tunnels 41, 51, 56 on the upper surface 2f of the main body 2. It further includes inserting into the body portion 2 through the first opening 21 . By using the ring-shaped structure 40 formed by assembling segments of precast concrete, the construction period can be greatly shortened and the construction cost can be greatly reduced.

Further, according to the present embodiment, the method for starting the closed shield machine 50 includes starting the closed shield machine 50 from the tunnel 51 constructed using the open shield machine 1 as a starting base. . In other words, the tunnel 51 functions as a starting base for the closed shield machine 50 . The tunnel 51 extends obliquely downward from the ground. Therefore, construction of a starting shaft for the closed shield machine 50 can be omitted.

Further, according to the present embodiment, the method of reaching the closed shield machine 50 includes making the closed shield machine 50 reach the tunnel 56 using the tunnel 56 constructed using the open shield machine 1 as the arrival base. . In other words, the tunnel 56 functions as an arrival base for the closed shield machine 50 . The tunnel 56 extends at an angle downward from the ground. Therefore, the construction of the arrival shaft for the enclosed shield machine 50 can be omitted.

FIG. 14 is a diagram showing a tunnel construction method according to the second embodiment of the present invention. Here, FIG. 14(a) is a sectional view taken along line II of FIG. 14(b). Differences from the first embodiment described above will be described.

In this embodiment, the invert 45 is installed inside the tunnel 41 (inside the existing ring-shaped structure 40). Invert 45 may be precast concrete or cast-in-place concrete.

In this embodiment, a plurality of inverted jacks 46 are provided inside the main body 2 . The inverted jack 46 is telescopic in the front-rear direction. The inverted jack 46 has a front end portion fixed to the main body portion 2 and a rear end portion capable of coming into contact with the existing invert 45 .

FIGS. 14A and 14B correspond to the step of inserting the new ring-shaped structure 40 into the main body 2 shown in FIGS. 8A and 8B.

In the process of inserting the new ring-shaped structure 40 into the main body 2, it is basically the blade that resists the face pressure when the propelling jack 7 is shortened in order to avoid the new ring-shaped structure 40. Friction of mouth 16 and passive earth pressure on rear surface 2b (rear plate 12) of main body 2. FIG. However, for example, when the groundwater level WL1 is high and it is assumed that the open shield machine 1 will be pushed back only by the friction of the cutting edge 16 and the passive earth pressure on the rear surface 2b of the main body 2, the inverted jack 46 is used as appropriate. , to prevent the open shield machine 1 from being pushed back.

The inverted jack 46 is a hydraulic jack composed of a cylinder 46a and a rod 46b. The front end portion of the cylinder 46a is fixed to the main body portion 2, and the rod 46b can advance and retract at the rear end portion side. By bringing the rear end portion of the rod 46 b of the inverted jack 46 into contact with the existing inverted jack 45 , the inverted jack 46 can be put in a stretched state.

In the present embodiment, when inserting the new ring-shaped structure 40 into the main body 2 from the first opening 21 of the upper surface 2 f of the main body 2 , the ring-shaped structure among the plurality of propelling jacks 7 and the inverted jacks 46 is inserted into the main body 2 . The part that evades the structure 40 is shortened, and the rest is kept in contact with the existing ring-shaped structure 40 and the invert 45 (i.e., stretched) to prevent the open shield machine 1 from being pushed back. .

Here, in FIGS. 14A and 14B, the upper propulsion jack 7-1 is shortened to avoid the newly installed ring-shaped structure 40, and the lower propulsion jack 7-2 and the inverted jack 46 are combined. shows a stretched state to prevent the open shield machine 1 from being pushed back.

In particular, according to this embodiment, the open shield machine 1 further includes an inverted jack 46 provided on the main body 2 . The propulsion jack 7 is extendable in the front-rear direction, and has a front end fixed to the main body 2 and a rear end abuttable against the ring-shaped structure 40 forming the tunnel 41 . The inverted jack 46 is extendable in the front-rear direction, and has a front end fixed to the main body 2 and a rear end that can abut against the invert 45 installed in the ring-shaped structure 40 . Therefore, when inserting the newly installed ring-shaped structure 40 into the main body 2, it is possible to prevent the open shield machine 1 from being pushed back due to the face pressure by appropriately replacing the propelling jack 7 and the inverting jack 46. can.

Although the ring-shaped structure 40 has a circular shape in this embodiment, the shape of the ring-shaped structure 40 is not limited to a circular shape. For example, the ring-shaped structure 40 may be oval or rectangular. Depending on the shape of the ring-shaped structure 40, the shape of the main body 2 (in particular, the shape of the bulkhead 10) and the shape of the skin plate 3 can be selected as appropriate.

The illustrated embodiments are merely illustrative of the present invention, and the present invention includes various improvements and modifications made by those skilled in the art within the scope of the claims in addition to those directly indicated by the described embodiments. It goes without saying that it is inclusive.
The claims as originally filed were as follows.
[Claim 1]
a box-shaped main body having a bulkhead on the front surface, a first opening on the top surface, and a second opening on the lower rear surface;
a propulsion jack provided on the main body for propelling the main body forward;
an excavator that forms an excavation groove in the ground ahead of the main body;
a mud discharge means for discharging mud in the excavated trench to the outside of the excavated trench;
with
The mud discharge means includes a mud discharge port formed through the bulkhead,
open shield machine.
[Claim 2]
2. The open shield machine of claim 1, wherein the bulkhead comprises guide rails for guiding movement of the excavator.
[Claim 3]
Further comprising an inverted jack provided in the main body,
The propulsion jack is extendable in the front-rear direction, has a front end fixed to the main body, and a rear end abuts against a ring-shaped structure constituting a tunnel,
The inverted jack is telescopic in the front-rear direction, has a front end fixed to the main body, and has a rear end that can abut against an invert installed in the ring-shaped structure.
An open shield machine according to claim 1 or claim 2.
[Claim 4]
a cylindrical skin plate connected to the second opening and extending rearward;
a tail seal on the inner peripheral surface of the skin plate and extending along the trailing edge of the skin plate;
An open shield machine according to any one of claims 1 to 3, further comprising:
[Claim 5]
A method for constructing a tunnel using the open shield machine according to any one of claims 1 to 4,
A method for constructing a tunnel, comprising forming the excavated groove by excavating mud ahead of the bulkhead with the excavator.
[Claim 6]
The muddy water discharge means further includes a muddy water discharge pipe through which muddy water flows from the muddy water discharge port, and an on-off valve that opens and closes the muddy water discharge pipe,
6. The tunnel construction method according to claim 5, further comprising opening the on-off valve when the main body portion is advanced by the propulsion jack.
[Claim 7]
7. The tunnel construction method according to claim 5 or 6, further comprising lifting the excavator from within the excavation trench to the ground by a lifting device prior to advancing the body portion by the propulsion jack.

DESCRIPTION OF SYMBOLS 1... Open shield machine, 2... Main body part, 2a... Front surface, 2b... Rear surface, 2c... Left side surface, 2ce... Extension surface, 2d... Right side surface, 2de... Extension surface, 2e... Curved surface, 2f... Top surface, 3... Skin plate 3a Tail portion 3b Tail seal 4 Excavator 4a Drum cutter 5 Mud supply means 6 Mud discharge means 7, 7-1, 7-2 Propulsion jack 7a Cylinder 7b Rod 10 Bulkhead 10a Front 12 Rear plate 13 Side plate 13e Extension 14 Right side plate 14e Extension 15 Lower plate 16 Blade Mouth 17 Friction cut 21 First opening 22 Second opening 25 Upper frame 26 Winch 27 Wire 30 Excavation groove 31, 32 Guide rail 35 Mud water supply Pipe, 35a...Outlet part, 36...Muddy water discharge port, 37...Muddy water discharge pipe, 37a...Upstream part, 38...On-off valve, 40...Ring-shaped structure, 41...Tunnel, 45...Invert, 46...Invert jack, 46a Cylinder 46b Rod 50 Closed shield excavator 50a Skin plate 50b Cutter head 50c Propulsion jack 50d Segment ring 51 Tunnel 52 Shield tunnel 54 Departure protection work 56... Tunnel, 57... Access protection work, C... Gap, G... Natural ground, WL1... Underground water level, WL2... Water level

Claims (10)

a box- shaped body having a bulkhead on the front surface, a first opening on the top surface, and a second opening on the bottom of the rear surface;
a propulsion jack provided on the main body for propelling the main body forward;
an excavator that forms an excavation groove in the ground ahead of the main body;
a mud discharge means for discharging mud in the excavated trench to the outside of the excavated trench;
with
The mud discharge means includes a mud discharge port formed through the bulkhead,
The open shield machine, wherein the bulkhead has a rectangular shape with a bottom semicircle connected to the bottom end of a vertically extending rectangle when viewed from the front. a guide rail provided on the bulkhead for guiding movement of the excavator ;
The excavator is configured to be able to move along the guide rail while gripping the guide rail,
The open shield machine according to claim 1 , wherein said guide rail extends in a U shape when viewed from the front . A cutting edge extending in a U-shape when viewed from the front is provided at a portion of the edge of the bulkhead other than the upper edge,
The open shield machine according to claim 1 or 2, wherein the excavator forms the excavated groove by excavating the ground inside the U-shaped cutting edge. a cylindrical skin plate connected to the second opening and extending rearward;
a tail seal on the inner peripheral surface of the skin plate and extending along the trailing edge of the skin plate;
further comprising
the rear surface of the main body portion has a semicircular rectangular shape at the lower end, and the second opening portion has a circular shape;
The open shield machine according to any one of claims 1 to 3 , wherein the inner diameter of the second opening is equal to the inner diameter of the skin plate . When viewed from above, the main body has a rectangular shape surrounded by the front surface, the rear surface, the left side surface, and the right side surface, and the left side surface and the right side surface each extend rearward from the rear surface. An open shield machine according to any one of claims 1 to 4, having an extended surface. Further comprising an inverted jack provided in the main body,
The propulsion jack is extendable in the front-rear direction, has a front end fixed to the main body, and a rear end abuts against a ring-shaped structure constituting a tunnel,
The invert jack is telescopic in the front-rear direction , has a front end fixed to the main body, and has a rear end contactable with an invert installed in the ring-shaped structure. 6. An open shield machine according to any one of claims 5 . A method for constructing a tunnel using the open shield machine according to any one of claims 1 to 6 ,
A method for constructing a tunnel, comprising forming the excavated groove by excavating mud ahead of the bulkhead with the excavator. The muddy water discharge means further includes a muddy water discharge pipe through which muddy water flows from the muddy water discharge port, and an on-off valve that opens and closes the muddy water discharge pipe,
8. The tunnel construction method according to claim 7 , further comprising opening the on-off valve when the main body portion is advanced by the propulsion jack. The muddy water discharge means further includes a muddy water discharge pipe through which muddy water flows from the muddy water discharge port, and an on-off valve that opens and closes the muddy water discharge pipe,
8. The tunnel construction method according to claim 7 , further comprising adjusting the opening and closing of the on-off valve so that the water level of muddy water in the excavated trench is higher than the groundwater level of the surrounding ground. Method. The tunnel according to any one of claims 7 to 9 , further comprising lifting the excavator from within the excavation trench to the ground by a lifting device prior to advancing the body portion by the propulsion jack. construction method.

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