JP2020079481A - Circumferential shield excavator - Google Patents

Abstract

To provide a circumferential shield excavator capable of improving the sludge efficiency by preferably discharging sludge while ensuring an appropriate working face holding force according to the posture during the excavation in the circumferential direction that extends in the vertical direction.SOLUTION: A double-circular circumference shield excavator 1 including a muddy water discharge device 4, which excavates in the circumferential direction so that the tunnel alignment draws a constant circumferential curve. The muddy water discharge device 4 includes: multiple sediment intake ports 212 formed on the partition wall 21 at the outer peripheral side, which partitions the chamber 3A at the working face side from the shield machine main body 2; multiple sludge-pipes 42 connected to each of the multiple intake ports 212; and a screw conveyor 43 located at the sediment intake port 212 in the sludge discharge pipe 42. The sediment intake ports 212 are arranged on the outer and inner circumferences in the circumferential direction. The multiple sludge discharge pipes 42 is provided so as to switch the communication state with the chamber 3A according to the posture of the shield machine main body 2.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a circumferential shield excavator.

Conventionally, in large-scale road tunnels and the like, large-section underground cavities are constructed at the junctions of main tunnels and ramp tunnels that are constructed by the shield method. As a method of constructing such a large-section underground cavity, for example, as shown in Patent Document 1, the outer shell portion of the branching and joining portion to be constructed is first constructed with a lining structure, and then the lining is performed. It is constructed by excavating the inside of the frame structure.
For such a lining structure, a plurality of outer shell tunnels are constructed in the outer shell part of the branch confluence part with a shield method at intervals in the circumferential direction of the branch confluence part, and ground protection work is applied by the freezing method. It is known that a structure is constructed by cutting open the outer shell tunnels next to each other, assembling the reinforcing bars and the formwork, and then pouring the concrete.

  In addition, when constructing the branch merge part, it surrounds the main tunnel and the ramp tunnel that were excavated in advance, and extends along the circumferential direction with the central axis being a direction substantially parallel to the tunnel axial direction. A construction method is known in which a circumferential tunnel having a rectangular cross section is constructed by a shield construction method, and the outer shell shield excavator is started by using this circumferential tunnel as a starting base to excavate the outer shell tunnel (for example, Patent Document 2). reference).

Japanese Patent No. 4958035 JP, 2014-43738, A

  However, when excavating with a shield excavator in a circumferential tunnel that is a tunnel line along the circumferential direction centered on the horizontal direction, the shield excavator during excavation must be advanced while changing to a downward position or an upward position. Become. Here, when the shield excavator is in a downward posture, it tries to approach the face due to gravity. On the other hand, when the attitude becomes upward, the shield excavator tries to move away from the face in the opposite way.Therefore, a control method according to the posture of the shield excavator is required to stably hold the ground of the face. It was

  Further, generally, a sediment inlet for discharging mud is arranged at the lower part of the partition wall. In other words, when the shield excavator is in an upward posture, the earth and sand intake port located at the lower portion can efficiently remove mud. On the other hand, when the shield excavator is in a downward posture, the sediment intake located at the bottom is located at the top of the bulkhead, so it may not be possible to fully drain the sludge, and the sludge drain efficiency will be reduced. Since there was a problem, there was room for improvement in that respect.

  The present invention has been made in view of the above-mentioned problems, and secures an appropriate face holding force according to the posture during excavation in the circumferential direction extending in the up-down direction, and suitable sludge can be discharged, An object is to provide a circumferential shield excavator capable of improving mud efficiency.

  In order to achieve the above-mentioned object, the circumferential shield excavator according to the present invention includes at least one mud pressure and mud sending/discharging mud device, and the tunnel line extends in the circumferential direction so as to draw a constant circumferential curve. A circumferential shield excavator to be excavated, wherein the mud sending and discharging device is provided with a plurality of earth and sand intakes provided on the outer peripheral side of a partition wall that separates the chamber on the cutting face side and the inside of the shield machine main body, and the plurality of the above. A mud pipe connected to each of the sediment intake ports, and a screw conveyor arranged at the sediment intake port of the mud pipe, at least two of the sediment intake ports being in the circumferential direction. Are arranged on the outer peripheral side and the inner peripheral side, and the plurality of the sludge discharge pipes are provided so that the communication state with the chamber can be switched according to the posture of the shield machine main body.

  In the present invention, when excavating in the circumferential direction by the circumferential shield excavator, the discharges connected to the respective earth and sand inlets on the outer circumferential side and the inner circumferential side in the circumferential direction according to the posture of the shield machine body. The open/closed state of the mud pipe can be switched to efficiently drain mud. That is, when the shield machine main body is in a posture in which the inner circumferential side in the circumferential direction is positioned lower than the outer circumferential side, the mud pipe connected to the earth and sand intake port on the outer circumferential side (referred to as outer circumferential side mud pipe) is Since the mud pipe that is closed and is connected to the sediment inlet on the inner circumference side (called the inner mud pipe) is connected to the chamber, the inner mud pipe is located at the bottom of the chamber. The excavated earth and sand can be efficiently discharged through the inner side mud pipe. Further, when the shield machine main body is in a posture in which the outer peripheral side in the circumferential direction is located lower than the inner peripheral side, by closing the inner peripheral side mud pipe and communicating the outer peripheral side mud pipe with the chamber, Since the outer peripheral mud pipe is located in the lower part of the chamber, the excavated soil can be efficiently discharged through the outer peripheral mud pipe.

  Further, in the present invention, since a screw conveyor is provided in each sludge discharge pipe, not only in the case of a mud type shield, but also in the case of a mud pressure type shield, the excavated earth and sand in the chamber is pulled up and discharged. can do.

  Furthermore, when the shield machine main body is in the downward posture, the shield machine main body behaves to fall toward the face. When the shield machine body is in the downward posture, it is possible to perform reliable drainage by applying a negative pressure as a fluid transport with a mud-type shield as a fluid transport method. It is preferable to use a muddy water shield capable of pressure control.

  Further, the circumferential shield excavator according to the present invention includes the mud pressure type and mud pressure type mud discharge devices, and the mud discharge method can be switched between the mud pressure type and the mud type in each of the plurality of mud discharge pipes. It may be characterized.

  In this case, the mud discharging method can be switched to the mud pressure type and the mud type according to the posture of the circumferential shield excavator, and the mud excavation can be advanced, so that the mud discharging efficiency can be improved. Therefore, the shield excavator can be controlled according to the posture, and the ground of the face can be stably held.

  Further, the circumferential shield excavator according to the present invention, by changing the communication state in the mud discharge pipe, excavates with a mud pressure shield when the shield machine body is in an upward posture, and when the shield machine body is in a downward posture, muddy water. It may be characterized in that it is provided so as to be switchable so as to excavate with a type shield.

  In this case, the mud pressure shield is used when the shield machine main body is in the upward posture, and the mud water shield is used when the shield machine body is in the downward posture, whereby the face can be held more reliably and stably.

  Further, the circumferential shield excavator according to the present invention may be configured such that regardless of the posture of the shield machine main body, the sludge discharge pipe located below is used to perform sludge discharge. ..

  In this case, the sludge can be efficiently discharged by using the sludge discharge pipe located on the lower side in any posture of the shield machine main body.

  Advantageous Effects of Invention According to the circumferential shield excavator of the present invention, appropriate face holding force is secured according to the posture during excavation in the circumferential direction that extends in the vertical direction, suitable sludge can be discharged, and sludge efficiency is improved. Can be made.

It is a perspective view showing a schematic construction state of a branching and joining part by an embodiment of the present invention. It is a figure which shows the tunnel line shape of the branch merge part shown in FIG. It is the sectional view on the AA line shown in FIG. FIG. 3A is a cross-sectional view taken along the line BB shown in FIG. 2, and FIG. 3B is a cross-sectional view of a branching and joining portion constructed by excavating the inside of the outer shell structure of FIG. It is CC sectional view taken on the line in FIG. 3, Comprising: It is a figure which shows the circumferential shield starting base after starting a compound circular circumferential shield excavator. It is sectional drawing which looked at the circumferential tunnel from the tunnel axial direction. It is a figure which shows the construction state of a circumferential tunnel, Comprising: It is a figure which showed each attitude|position of the compound circular circumference shield excavator during excavation. It is a side view which shows the structure of a compound circular circumference shield excavator. It is the front view which looked at the compound circular circumference shield excavator from the front.

  Hereinafter, a circumferential shield excavator according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the compound circular circumference shield excavator 1 (circumferential shield excavator) according to the present embodiment (see FIGS. 7 and 8) is, for example, in the ground in advance in a large road tunnel. The present invention is applied to the construction in which the branch/merging portion 10 having a large cross section is constructed at a portion where the ramp tunnel 12 joins/branches with respect to the main tunnel 11 constructed by the shield construction method.

The branching and merging portion 10 surrounds the outer sides of the main tunnel 11 and the ramp tunnel 12, and includes a plurality of outer shell tunnels 13, 13,... Constructed so as to extend parallel to the branching and merging portion 10. It is a part. The branching/merging portion 10 forms an outer shell body structure 10A that is continuous in the circumferential direction by excavating and connecting the outer shell tunnels 13 that are adjacent to each other in the circumferential direction, and further, the outer shell body structure 10A. It is constructed by excavating the inside of. When constructing the branching and merging portion 10, as shown in FIG. 3 and FIGS. 4A and 4B, firstly, the main line tunnel 11 and the ramp tunnel 12 are preliminarily constructed, and the inside of the outer shell structure 10A is installed. During excavation, segments of the main tunnel 11 and the ramp tunnel 12 that are built inside the outer shell structure 10A are disassembled.
The plurality of outer shell tunnels 13 are constructed by excavating the outer shell shield excavator 14 using the circumferential tunnel 15 preliminarily constructed in a part of the branching and joining section 10 as a starting base (outer shell shield starting base 150). It

  The outer shell shield excavator 14 is excavated outside the main tunnel 11 and the ramp tunnel 12 along the extending direction of the branching and joining section 10 from the outer shell shield starting base 150.

  The outer shell shield starting base 150 (circumferential tunnel 15) is constructed by the compound circular circumferential shield excavator 1 (see FIG. 7 and FIG. 8) that has a spectacles shape in cross-sectional view, as shown in FIG. 2 and FIG. , A circular tunnel 15 having a pair of circular tunnels 15A and 15B stacked in the central portion and having a cross-sectional spectacle shape, and formed into a ring shape along a circumferential direction E centered on an axis parallel to the central axis of the main tunnel 11. Has been constructed.

  As shown in FIG. 6, the outer shell shield starting base 150 is a spectacle-shaped circumferential segment 151 constructed at the time of the excavation of the compound circular circumferential shield excavator 1, and the center of the circumferential segment 151 in the left-right direction in cross section. The upper and lower constricted portions 15a, 15a are connected to each other, and the central pillar 152 extends in the vertical direction.

  Here, as shown in FIG. 5, in the circumferential tunnel 15 forming the outer shell starting point 150, the extension direction of a straight line passing through the respective tunnel centers O1 and O2 of the pair of circular tunnels 15A and 15B is defined as the left-right direction X. That is, the direction orthogonal to the left-right direction X in cross section is called the up-down direction.

As shown in FIG. 6, one starting side circular tunnel 15A of the circumferential tunnel 15 (outer shell shield starting base 150) is used as a starting space of the outer shield excavator 14, and the material is placed inside the shield after starting. It is used as a material loading space for sending in and a unloading space for excavated soil.
The other proximal end side circular tunnel 15B is used as a space for disposing reaction force receiving equipment when the outer shell shield excavator 14 starts, and after the start, a material carrying space for sending materials into the shield and carrying out excavated soil. Used as space. Note that reference numerals 14A, 14B, and 14C in FIG. 6 indicate examples of the material carrying-in space and the excavating soil carrying-out space after the outer shell shield excavator 14 has started.

  The diameter of the pair of circular tunnels 15A and 15B is set to a size that allows the outer shell shield excavator 14 to start. Further, in the starting side circular tunnel 15A, the wall surface 15b on the face of the starting portion of the outer shell shield excavator 14 has an outer wall formed by the circumferential segment 151 when the double circular circumferential shield excavator 1 is being advanced. The material is, for example, concrete that can be cut with the cutting cutter of the outer shell shield excavator 14 at a suitable timing, as in a general shield construction method. It is also possible to use a segment in which the wall surface 15b made of a material that can be cut by a cutter is incorporated.

  As shown in FIG. 7, the double-circle circumferential shield excavator 1 includes one of the circumferential directions E from the circumferential shield starting base 17 constructed by widening and excavating the ramp tunnel 12 (shown by reference numeral E1 in FIG. 7). 7A to 1F in the circumferential direction E1 in the order of reference numerals 1A, 1B,... 1F in FIG. 7 to arrive at the circumferential shield starting base 17 as a reaching base. In this way, the double-circle circumferential shield excavator 1 can be advanced so that the tunnel line draws a constant circumferential curve. 151 is sequentially assembled as the tunnel is dug.

As shown in FIGS. 8 and 9, the double circular circumferential shield excavator 1 includes a shield machine main body 2 having an eyeglass-shaped skin plate 20 forming an outer shell, and a plurality of shield machine main body 2 provided on the front side of the shield machine main body 2. It is provided with a cutter head 3 having a cutter bit, a sending and discharging device 4 for sending muddy water to the cutter head 3 and discharging excavated soil, and an erector device 5 for assembling the circumferential segment 151.
Here, in the double circular circumference shield excavator 1, the direction along the excavator center line is referred to as the front-back direction Z, the face of the face along the front-rear direction Z is referred to as the front side, the front side, and the opposite side (start side) is the rear side. Side, back.

  As shown in FIG. 8, the shield machine main body 2 is provided in the front body plate 20A and the skin plate 20 that has a spectacle shape in a sectional view and is divided and joined to the front body plate 20A and the rear body plate 20B in the front-rear direction Z. The partition wall 21 for partitioning the chamber 3A on the cutting face side and the inside of the shield machine, the main body ring 22 protruding rearward from the outer peripheral portion of the partition wall 21, and the rear portion of the main body ring 22 arranged at intervals along the outer periphery. Further, a plurality of propulsion jacks 23 and a natural ground gripper 24 that can project from the main body ring 22 toward the natural ground side are provided.

  The skin plate 20 is a spectacle-shaped cylindrical body having an outer cross-sectional shape and a constricted portion 20a (see FIG. 9) formed in the left and right central portions, and the front torso plate 20A is circular with respect to the rear torso plate 20B. The inner circumferential side in the circumferential direction E is refracted and joined at a predetermined angle according to the linear curvature of the double circular circumferential shield excavator 1, and the portion located on the inner circumferential side in the circumferential direction E is located on the outer circumferential side. It is integrally formed with a shape whose length in the front-back direction Z is smaller than that of the portion.

The partition wall 21, the main body ring 22, and the natural ground gripper 24 are arranged inside the front body plate 20A. The front trunk plate 20A is formed with an opening through which the natural ground gripper 24 can project outward, and by allowing the natural ground gripper 24 to project from this opening with an appropriate amount of projection, the excavated wall surface G By applying a reaction force to the natural ground, it is possible to control the direction of the double circular circumference shield excavator 1 at the time of excavation and prevent the shield machine body 2 from deviating from the track in the circumferential direction E. .
In front of the partition wall 21 and inside the front body plate 20A, a space (chamber 3A) is formed in which the mud water sent by the mud sending and discharging device 4 and the excavated earth and sand are stirred.

  Inside the rear body plate 20B, the circumferential segment 151 is assembled by the erector device 5 along with the excavation. A tail seal 201 that seals a gap with the outer circumferential surface of the assembled circumferential segment 151 is attached to the rear portion of the rear body plate 20B over the entire circumference of the rear body plate 20B. Here, the tail seals 201 are wire brushes, and are arranged in three rows in the length direction of the skin plate 20 (the front-back direction Z).

  The skin plate 20 may be equipped with a backfilling simultaneous injection device (not shown) for injecting the backfilling material at the same time as the excavation is performed between the skin plate 20 and the ground surface. When excavating in the circumferential direction E1 using the double circular circumferential shield excavator 1 as in the present embodiment, the change in posture of the excavator is larger than when excavating in the substantially horizontal direction, and the cutter The wall surface of the excavated ground immediately after excavation easily collapses.Therefore, by providing a backfill simultaneous injection device, the gap between the excavated ground and the backfill material is filled immediately after the excavation and the backfill material is filled. Can be stabilized. Therefore, the attitude control of the shield excavator due to the collapse of the excavated ground becomes easy, and the direction control of the excavation in the circumferential direction E, which is difficult to control the direction, can be accurately performed.

The partition wall 21 is a partition wall that separates the face of the face from the inside of the shield machine so that water and earth and sand from the face do not flow into the inside of the shield machine body 2 (inside the shield machine). As shown in FIG. 9, the partition wall 21 has a shape in which two circular portions 21A and 21B are partially overlapped, and the cutter rotation shaft 31 is rotatably supported at the centers C1 and C2 of the circular portions 21A and 21B. ing. A ring gear 32 for rotating a cutter, which will be described later, is supported on each of the circular portions 21A and 21B so as to be rotatable around the centers C1 and C2 of the circular portions 21A and 21B.
Further, as shown in FIG. 8, the partition wall 21 is provided with a muddy water inlet 211 for sending mud and a sediment inlet 212 which communicate with the inside of the chamber 3A from the inside of the shield machine. The muddy water inlet 211 and the earth and sand inlet 212 are connected to the pipes of the mud sending and discharging device 4 (mud sending pipe 41 and mud discharging pipe 42 described later).

  The body ring 22 includes an outer peripheral ring 22A to which the propulsion jack 23 is fixed, and an inner peripheral ring 22B that is provided inside the outer peripheral ring 22A and to which the cutter driving motor 25 is fixed. The length of the outer peripheral ring 22A in the front-rear direction Z is formed such that the outer peripheral side in the circumferential direction E is longer than the inner peripheral side.

  The outer peripheral ring 22A is formed in a spectacle shape along the outer peripheral portion of the partition wall 21, and the rear end surface 22a has a rear end portion of the front body plate 20A of the skin plate 20 (a boundary between the front body plate 20A and the rear body plate 20B is bent. Section). A plurality of propulsion jacks 23, 23,... Are fixed along the outer periphery to the rear end surface 22a of the outer peripheral ring 22A with the jack pressing surface 23a facing rearward. The outer peripheral ring 22A is provided with a natural ground gripper 24 capable of projecting toward the natural ground side in a direction orthogonal to the tunnel axis direction of the double circular circumferential shield excavator 1.

  The propulsion jack 23 is fixed to the main body ring 22 so that the telescopic rod can project rearward from the rear end surface 22 a of the main body ring 22. By extending the telescopic rod of the propulsion jack 23, the propulsion force of the shield body 2 is obtained by pressing against the front surface of the segment 151 that is sequentially assembled inside the rear body plate 20B of the skin plate 20 to take a reaction force. There is. The propulsion jack 23 may be equipped with a rolling prevention control device.

  The ground gripper 24 is a posture control means of the shield machine main body 2, and the reaction force surface 24a protruding outward is inclined so that the protruding length gradually increases from the front to the rear. The natural ground gripper 24 advances the double-circular circumferential shield excavator 1 while pressing the reaction surface 24a against the natural excavation ground G, so that the double-circular circumferential shield excavator 1 deviates from the circumferential direction E. The reaction force against the force toward the outer peripheral side or the inner peripheral side can be applied to the ground.

  The inner peripheral ring 22B is formed in a circular ring shape provided coaxially with the centers C1 and C2 of the circular portions 21A and 21B of the partition wall 21. The inner ring 22B is provided with a plurality of electric cutter drive motors 25 at intervals in the circumferential direction. A cutter ring 32 is supported inside the inner peripheral ring 22B so as to be rotatable around the centers C1 and C2.

  As shown in FIGS. 8 and 9, the cutter head 3 includes a cutter rotating shaft 31 provided at the centers C1 and C2 of the circular portions 21A and 21B of the partition wall 21 and a pair of cutter rotating shafts supported by the partition wall 21. A cutter ring 32 rotatably provided around each of the shafts 31, a center cutter 33 provided at the tip of the cutter rotating shaft 31, and a cutter ring 32 are supported, and the center portion is fixed to the center cutter 33. The spoke type cutaway pork 34A, 34B and the copy cutter 35 provided on the outer peripheral ends of the cuttus pork 34A, 34B are provided.

The cutter rotation shaft 31 including the center cutter 33 is rotatably supported by a rotary joint (not shown) provided in the partition wall 21.
As shown in FIG. 8, the cutter ring 32 is supported by the inner peripheral ring 22B of the partition wall 21 and the front end thereof is integrally supported by the cut-and-spokes 34A, 34B via a connecting member 36. A ring gear 32a is formed on the outer peripheral portion of the cutter ring 32, the motor rotation shafts 25a of a plurality of cutter drive motors 25 are meshed with each other, and are provided so as to be rotatable together with the cutter rotation shaft 31 by the drive of the cutter drive motor 25.

  As shown in FIG. 9, the pair of cutass pork 34A and 34B are arranged in a state of intersecting with the cutter rotation shaft 31 so as to be X-shaped when viewed from the face of the face. A large number of cutter bits are attached to the front surfaces of the cutter spokes 34A and 34B along the length direction of the spokes. Rotation is controlled so that the cut-and-spokes 34, 34 provided on each of the circular portions 21A, 21B rotate about the cutter rotation shaft 31 so as not to interfere with each other, so that a cross section having a spectacle shape can be excavated.

  The copy cutter 35 is provided so as to be capable of projecting and retracting from a part of the spoke tip end portion 34a of the cutas pork 34A, 34B toward the outside of the spoke shaft. The copy cutter 35 is to excavate the outer side of the outer peripheral surface of the skin plate 20 by projecting toward the natural ground side with a predetermined amount of protrusion at a predetermined cutter rotation position. That is, the copy cutter 35 functions as the attitude control means of the shield machine body 2 like the natural ground gripper 24.

The mud sending and discharging device 4 includes a mud sending pipe 41 for sending mud into the face chamber 3A, a pair of mud sending pipes 42 (42A, 42B) for discharging the excavated sediment mixed with the mud, and a drain And a screw conveyor 43 provided at the intake in the mud pipe 42.
The mud feed pipe 41 is connected to a muddy water inlet 211 provided at the center of each circular portion 21A, 21B of the partition wall 21. During the excavation, mud water is injected into the chamber 3A from the mud feed pipe 41 to keep the cutting face at a constant pressure, and the mud can be mixed with the excavated earth and sand to be in an appropriately viscous mud discharge state.

  The sludge discharge pipes 42A and 42B are connected to the earth and sand intake ports 212 provided on the outer peripheral side and the inner peripheral side of the circular portions 21A and 21B of the partition wall 21, respectively. The pair of mud discharge pipes 42A and 42B are provided in the shield machine so as to be inclined so as to be in the center of the cross section toward the rear from the sand intake port 212, and to the sediment discharge pipe 44 arranged in the center of the cross section. Connected to meet. A screw conveyor 43 is provided at the tip of each of the sludge discharge pipes 42A and 42B. The screw conveyor 43 is arranged such that the tip of the screw protrudes from the sediment intake port 212 and is located in the chamber 3A, and by rotating the screw during excavation, the excavated sediment is taken into the mud pipe 42 and the sediment discharge pipe 44. Exhaust through.

  The pair of mud discharge pipes 42A and 42B are provided so as to be alternately switchable with respect to the sediment discharge pipe 44. Alternatively, both of the pair of mud discharge pipes 42A and 42B can be simultaneously in communication with the sediment discharge pipe 44.

  The erector device 5 is provided inside the shield of the partition wall 21 for each of the circular portions 21A and 21B. Each of the erector devices 5 has a ring-shaped revolving frame 51 centered on the circular portions 21A and 21B, and a gripping device 52 supported by the revolving frame 51. The gripping device 52 includes a gripping portion to which the segment piece of the circumferential segment 151 can be attached and detached, and is provided so as to be slidable in the front-rear direction Z with respect to the revolving frame 51. Further, the gripping device 52 is provided so that the posture of the gripped segment piece of the circumferential segment 151 can be slid, for example, in the circumferential direction, the front-rear direction, the radial direction, etc., and the segment piece can be assembled at a predetermined position.

Next, a method of constructing the circumferential tunnel 15 using the above-mentioned double circular circumferential shield excavator 1, and a method of excavating the outer shell tunnel 13 by further using the circumferential tunnel 15 to construct the branch confluence portion 10. The method will be described with reference to the drawings.
First, as shown in FIG. 1 and FIG. 7, a starting base (circumferential shield starting base 17) of the double circular circumferential shield excavator 1 for excavating the circumferential tunnel 10 is formed on a part of the side wall of the ramp tunnel 12. Install.

  Specifically, the propulsion unit 18 is set at a predetermined position of the ramp tunnel 12 with the cutter head facing outward in the radial direction of the ramp tunnel 12, and propelled by the propulsion method. Here, at the time of propulsion by the propulsion device 18, the frozen soil improving portion 100 is formed by performing ground improvement by freezing the ground of the installation position of the circumferential shield starting base 17 and the surrounding construction area by a freezing method. At this time, the frozen soil improving section 100 is provided by radially disposing a plurality of freezing tubes 16 from the propulsion unit 18. After that, the ground shield starting base 17 having a substantially rectangular box-shaped region is provided by excavating the ground inside the frozen soil improving portion 100 by a conventional method. Then, the propulsion unit 18 whose propulsion has been completed is disassembled and removed. The circumferential shield starting base 17 to be constructed is, as shown in FIGS. 1 and 2, constructed in a box shape by reinforced concrete construction, and is set to a size capable of starting the compound circular circumferential shield excavator 1.

  The ground improvement carried out here is not limited to forming the frozen soil improving portion 100 by the freezing method, and another ground improving method may be adopted. For example, it is also possible to adopt another ground improvement such as a chemical solution injecting process by driving an injection pipe from the rear of the propulsion unit 16 toward a target improvement area and injecting a chemical solution. Alternatively, if the ground is a hard ground that can stand on its own, ground improvement can be omitted.

  Next, as shown in FIG. 7, in the circumferential shield starting base 17, the compound circular circumferential shield excavator 1 is assembled, and reaction force receiving and subsequent equipment necessary for excavation are also installed to prepare for the start. To do. Since the double circular circumferential shield excavator 1 excavates along the circumferential direction E1, it is set at the circumferential shield starting base 17 with the cutter head 3 facing downward. Here, the starting hole part 17a of the circumferential shield starting base 17 is constructed with a material that can be excavated by the double circular circumferential shield excavator 1.

  Next, the compound circular circumference shield excavator 1 is started, and the eyeglass-shaped circumferential segment 151 is assembled within the rear trunk plate 20B of the shield machine main body 2 along with the excavation as in the conventional shield construction method. Then, the work of injecting the backfill material between the segment 151 and the excavated ground is sequentially repeated, and as shown in FIGS. 3 and 4A and 4B, outside the main tunnel 11 and the ramp tunnel 12. By digging in the circumferential direction E to reach the circumferential shield starting base 17 again, the spectacle-shaped circumferential tunnel 15 in cross section is constructed.

  As shown in FIG. 8, in the double circular circumferential shield excavator 1, the skin plate 20 is aligned in a tunnel shape and the front body plate 20A is bent inward in the radial direction of the circumferential direction E with respect to the rear body plate 20B. Since they are joined, the stroke of the propulsion jack 23 is also extended so that the outer peripheral side is longer than the inner peripheral side so as to excavate, so that the circumferential tunnel 15 is constructed by excavating in a tunnel alignment in the circumferential direction E. Specifically, the items are dug counterclockwise (in the direction of arrow E1) in the order of reference numerals 1A to 1E shown in FIG. That is, the double circular circumferential shield excavator 1 first starts excavation from the circumferential shield starting base 17 in a downward attitude (postures of reference numerals 1A and 1B) and, after passing through the lowermost portion, gradually rises in the upward posture (reference numeral 1C). 1D, 1E posture) while heading to the uppermost part, passing through the uppermost part, and then excavating again while changing to the downward facing posture (reference symbols 1F, 1A) to reach the circular shield starting base 17 again. The circumferential tunnel 15 having a spectacle-shaped cross section is constructed by excavating once in the circumferential direction E.

  Further, in the double circular circumference shield excavator 1, as shown in FIG. 8, by excavating the natural ground gripper 24 provided on the outer peripheral portion of the partition wall 21 toward the excavated natural rock side, the shield is obtained. The force that the machine body 2 tends to move toward the outer peripheral side can be suppressed, and the excavation direction can be easily controlled. The amount of protrusion of the natural ground gripper 24 at this time is preferably changed in real time according to the hardness of the natural ground during excavation, the condition of geology, the position and orientation of the shield machine body 2, and the like.

  Next, as shown in FIGS. 1 and 2, the constructed circumferential tunnel 15 is used as an outer shell shield starting portion 150, and is placed at a predetermined position in the circumferential direction E on the starting side circular tunnel portion 15A of the outer shell shield starting portion 150. An outer shell shield excavator 14 having a circular cross section is arranged to proceed with excavation. A reaction force wall for starting the outer shell shield excavator 14 and subsequent equipment are arranged in the proximal circular tunnel portion 15B of the outer shell shield starting portion 150. The outer shell shield excavator 14 may use the outer shell shield starting unit 150 to make a plurality of simultaneous excavations. The earth and sand excavated by the outer shell shield excavator 14 is transported to the starting side in the outer shell tunnel 13 that has been excavated, and is discharged from the outer shell shield starting portion 150 to the outside through the circumferential shield starting base 17 and the ramp tunnel 12. To do. Further, materials such as segments necessary for excavation are carried from the inside of the ramp tunnel 12 into the outer shell tunnel 13 under excavation via the circumferential shield starting base 17 and the outer shell starting portion 150.

  The outer shell tunnels 13 thus excavated by the outer shield excavator 14 are constructed at predetermined intervals in the circumferential direction E, and the main tunnel 11 and the ramp tunnel 12 are constructed by these outer shell tunnels 13. A part of the outer shell skeleton structure 10A is constructed around the. The outer shell shield excavator 14 digs through the outer shell tunnel 13 to reach the intended bulging wall of the branching and joining section 10, dismantles and collects it, assembles it again with the outer shell shield starting section 150, and starts it. The outer shell tunnel 13 may be repeatedly used so as to be constructed.

Subsequently, as shown in FIGS. 4A and 4B, ground improvement is performed between the outer shell tunnels 13 adjacent to each other in the circumferential direction E by a freezing method, a chemical injection method, or the like. After that, the outer shell tunnels 13 and 13 are cut open, and the outer shell tunnels 13 and 13 are connected to each other by steel panels (not shown) arranged in the inner and outer peripheral portions, and the inner and outer steel panels are connected to each other. By filling concrete between them, the outer shell body structure 10A is integrated, thereby forming the outer shell body structure 10A having a supporting function and a water stopping function.
After that, the inside of the outer shell structure 10A is excavated, and the segments of the main tunnel 11 and the ramp tunnel 12 at the locations covered by the outer shell structure 10A are disassembled and removed to construct a branching and merging portion 10 forming a large space. be able to.

Next, the operation of the circumferential shield excavator will be described in detail with reference to the drawings.
In the present embodiment, as shown in FIG. 7, when excavating in the circumferential direction E1 by the double circular circumferential shield excavator 1, as shown in FIGS. 8 and 9, depending on the posture of the shield machine body 2, The open/closed states of the sludge discharge pipes 42A, 42B connected to the outer and inner sides of the earth and sand inlets 212A, 212B in the circumferential direction E1 can be switched to efficiently discharge sludge.

  That is, when the shield machine main body 2 is in a posture in which the inner circumferential side in the circumferential direction E1 is located lower than the outer circumferential side (postures 1D, 1E, 1F shown in FIG. 7), the outer peripheral side sand intake port. By closing the outer peripheral side sludge discharge pipe 42A connected to 212A and communicating the inner peripheral side sludge discharge pipe 42B connected to the inner peripheral side sediment intake port 212B with the chamber 3A, the inner peripheral side sludge discharge pipe Since 42B is located in the lower part of the chamber 3A, the excavated soil can be efficiently discharged through the inner peripheral side mud pipe 42B.

  Further, when the shield machine main body 2 is in a posture in which the outer peripheral side in the circumferential direction E1 is located lower than the inner peripheral side (postures 1A, 1B, and 1C shown in FIG. 7), the inner peripheral side sludge discharge pipe 42B. Is closed and the outer peripheral side mud pipe 42A is communicated with the chamber 3A, and the outer peripheral side mud pipe 42A is located in the lower part of the chamber 3A. Therefore, the excavated sediment is efficiently discharged through the outer peripheral side mud pipe 42A. be able to.

  Further, in the present embodiment, since the screw conveyor 43 is provided in each sludge discharge pipe 42, the screw conveyor 43 is used not only in the case of the muddy water type shield but also in the case of the mud pressure type shield in the chamber 3A. The excavated soil can be pulled up and discharged. That is, when the double circular circumferential shield excavator 1 is in the upward posture (postures 1C, 1D, 1E shown in FIG. 7), it is a mud pressure shield, and the downward posture (postures 1F, 1A, 1B shown in FIG. 7). In this case, by switching to the muddy water shield, the face can be held more reliably and stably.

  That is, the compound circular circumference shield excavator 1 starts from the circumference shield starting base from the posture of reference numeral 1A, and in the posture of reference numeral 1B, excavates with the outer peripheral mud pipe 42A in a muddy type, and the cutter head 3 circles. When the outer peripheral sludge pipe is changed to the mud system at a time point when it is oriented in a substantially horizontal direction near the lower end of the circumference, the compound circular circumferential shield excavator 1 excavates in the posture of reference numeral 1C. After that, when the double-circle circumferential shield excavator 1 is directed substantially vertically upward, the sludge is switched to be discharged to the inner-circumferential sludge pipe 42B. Excavate in this posture. Further, with the cutter head 3 oriented in a substantially horizontal direction near the upper end of the circumference, the mud drainage method of the inner circumferential mud pipe 42B is switched to the mud type, and the double circular circumferential shield excavator 1 is set to the position of 1F. Excavate and reach the circumference shield start base to complete the excavation of the circumference shield.

In such a construction, when the double circular circumference shield excavator 1 is in the downward posture, the double circular circumference shield excavator 1 behaves to fall to the face side. When the double circular circumferential shield excavator 1 is in the downward posture, the mud type shield is used and the negative pressure is applied by fluidizing the mud discharging method, whereby reliable mud discharging can be performed. Since it is a fluid, it is preferable to use a muddy water shield that enables precise pressure control.
In the case of a muddy water type shield excavator, it is relatively easy to discharge mud upward.

  As described above, the mud discharge method can be switched to the mud pressure type and the mud type according to the posture of the double circular circumferential shield excavator 1, and excavation can be performed, so that the mud discharge efficiency can be improved. Therefore, control according to the posture of the compound circular circumference shield excavator 1 becomes possible, and the ground of the face can be stably held.

  As described above, in the circumferential shield excavator according to the present embodiment, suitable face holding force is secured according to the posture during excavation in the circumferential direction extending in the vertical direction, suitable sludge can be generated, The efficiency can be improved.

  Although the embodiment of the circumferential shield excavator according to the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the spirit of the present invention.

  For example, in the present embodiment, the glasses-shaped double circular circumferential shield excavator 1 is adopted as the circumferential shield excavator having the plurality of sludge pipes 42, but it is a shield excavator having a cross section of glasses. The present invention is not limited to this, and can be applied to a shield excavator that is excavated in a circumferential direction with a circular cross section or a rectangular cross section.

Further, in the present embodiment, the outer peripheral side sludge discharge pipe 42A and the inner peripheral side sludge discharge pipe 42B are provided in a pair, but the number is not limited to two, and three are provided. It does not matter even if the above-mentioned mud pipe is provided.
Further, in the present embodiment, the mud water discharge device 4 intended for the muddy water type shield is used, but a mud pressure type shield may be used.

  Further, for example, the cross-sectional shape and size of the double circular circumferential shield excavator 1, the refraction angle of the skin plate 20, etc., are the tunnel alignment of the circumferential tunnel 15 and the outer shell shield excavator for excavating the outer shell tunnel 13. It can be appropriately set according to conditions such as the outer diameter of 14. For example, the length dimension in the front-rear direction Z of the front body plate 20A and the rear body plate 20B of the skin plate 20 can be changed.

  Further, in the present embodiment, the front body plate 20A of the skin plate 20 is provided with the natural ground gripper 24 that can project toward the natural ground, but such a natural ground gripper 24 can be omitted. However, a ground gripper having another shape may be applied.

In addition, the position, size, construction method, etc. of the circumferential shield starting base 17 for launching the double circular circumferential shield excavator 1 depend on the outer diameter, the arrangement, the ground conditions, etc. of the main line tunnel 11 and the ramp tunnel 12. It is possible to set appropriately. Further, it is possible to appropriately select at which point and how to switch the sludge discharge pipe and the sludge discharge method according to the ground conditions and the like.
Further, the size of the outer shell portion (outer shell structure 10A) forming the branching/merging portion 10, the structure of the outer shell, and the construction method are not limited to those in the above-described embodiment, and the road tunnel and ground conditions to be set are set. It is appropriately set according to specifications such as.

  Further, although the present embodiment is an application example in the case of constructing a large-section road tunnel, it is widely used in constructing tunnels of various scales, uses, and forms having a large-section underground cavity as described above. It is applicable, and various design changes can be made depending on the size and form of the underground cavity in the tunnel to be constructed and considering various conditions such as the surrounding environment.

  In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with known constituent elements without departing from the spirit of the present invention.

1 Double circular circumference shield excavator (circumferential shield excavator)
2 Shield machine main body 3 Cutter head 3A chamber 4 Sending and discharging mud device 10 Branching and merging section 11 Main tunnel 12 Lamp tunnel 13 Outer shell tunnel 14 Outer shell shield excavator 15 Circular tunnel 15A Start side circular tunnel 15B Base side circular tunnel 17 Circumferential shield starting base 20 Skin plate 20A Front body plate 20B Rear body plate 21 Partition wall 24 Ground gripper 41 Mud pipe 42 Mud pipe 42A Outer peripheral mud pipe 42B Inner peripheral mud pipe 43 Screw conveyor 44 Sediment discharge pipe 150 Outer shell shield starting base 151 Circumferential segment 212A, 212B Sediment intake E, E1 Circumferential direction Z Front-rear direction C1, C2 Center of circular part of bulkhead O1, O2 Center of circular tunnel

Claims (4)

A circumferential shield excavator that is equipped with at least one mud pressure type and muddy water type mud sending/discharging device, and is tunneled in a circumferential direction so that a tunnel line draws a constant circumferential curve.
The mud sending and discharging device,
A plurality of earth and sand inlets provided on the outer peripheral side of the partition that divides the chamber on the face side and the inside of the shield machine main body,
A sludge pipe connected to each of the plurality of sediment intake ports,
A screw conveyor disposed at the earth and sand intake of the mud pipe,
At least two of the earth and sand inlets are arranged on the outer peripheral side and the inner peripheral side in the circumferential direction,
The circumferential shield excavator, wherein the plurality of mud discharge pipes are provided so that the communication state with the chamber can be switched according to the posture of the shield machine main body. It is equipped with the mud pressure type and mud type of the sending and discharging mud device,
The circumferential shield excavator according to claim 1, wherein a mud discharge method can be switched between a mud pressure type and a mud type in each of the plurality of mud discharge pipes.   By changing the communication state in the mud pipe, excavation is carried out by the mud pressure shield when the shield machine body is in the upward posture, and it is switchably provided so as to be excavated by the mud shield in the downward posture. The circumferential shield excavator according to claim 1 or 2, characterized in that:   The circle according to any one of claims 1 to 3, wherein the sludge discharge pipe located below is used to discharge sludge regardless of the posture of the shield machine body. Zhou shield excavator.

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