JP5458386B2 - Tunnel excavator and tunnel excavation method - Google Patents

Description

  The present invention relates to a tunnel excavator and a tunnel excavation method for excavating by adding a bubble material or bentonite to excavated soil.

Conventionally, a tunnel excavator with a rectangular cross section has been adopted because it is often reasonable to make the cross-sectional shape of a relatively small tunnel provided in an urban area a rectangular cross section rather than a circular cross section. . As a cutting mechanism of such a tunnel excavator, a screw-shaped cutter (disposed in a substantially horizontal direction orthogonal to the excavating direction and having a cutting bit for cutting earth and sand on the outer peripheral portion of a spiral blade ( In some cases, a plurality of screw cutters are arranged in parallel in the vertical direction at the tip of the excavator body (see, for example, Patent Documents 1, 2, and 3).
Such a mechanism with a screw cutter is a rotary drive of a hydraulic motor or the like that rotates the spiral blades to cut the earth and sand while transferring the earth and sand cut in the left-right direction, and in the direction of the axis of rotation of the screw cutter near the screw end The excavated sediment is discharged to the rear of the shield machine by a screw conveyor installed at right angles to the shield machine.

Japanese Patent No. 3667717 Japanese Patent Laid-Open No. 11-229774 Japanese Patent Publication No. 7-59878

However, the conventional tunnel excavator has the following problems.
That is, the screw cutter mechanism disclosed in Patent Documents 1, 2, and 3 excavates the natural ground in the width direction with a horizontal screw cutter and transfers the earth and sand in the left-right direction (lateral direction). Since the transfer capability in the left-right direction is constant, the amount of soil transported inside the screw increases and the screw internal pressure increases as the soil is removed in the direction of the rotation axis of the screw cutter. For this reason, the pressure of the screw cutter corresponding to the earth pressure of the natural ground to be cut is not constant in the axial direction (tunnel width direction) range, and a pressure difference occurs, so the earth pressure of the natural ground partially decreases. There was a risk of causing land subsidence.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a tunnel excavator and a tunnel excavation method that can stabilize the face by equalizing the earth pressure in the chamber. To do.

In order to achieve the above object, the tunnel excavator according to the present invention is a tunnel excavator that excavates with a cutter on the face surface side of the excavator body, and is arranged around the horizontal rotation axis at a predetermined interval in the axial direction thereof. Excavation bits are provided to protrude outward, and excavation cutters arranged with the axial direction facing the tunnel width direction are provided in a plurality of stages in the vertical direction along the front surface of the excavator body, and in the vicinity of the excavation cutter In addition, a discharge port for the additive material that plastically fluidizes the excavated sediment is provided, and a paddle screw that stirs the excavated sediment and plastically fluidizes the excavated sediment in the chamber behind the excavated cutter. and provided in parallel, the drilling cutter has a plurality of drill bit, the cutter rotational center side each drill bit adjacent the cutter center of rotation watches horizontal shaft from the front It is characterized by not being arranged on parallel identical lines.

Further, in the tunnel excavation method according to the present invention, excavating bits are provided around the horizontal rotating shaft so as to protrude outwardly at predetermined intervals in the axial direction, and the axial direction is arranged in the tunnel width direction. A plurality of stages are provided in the vertical direction along the front surface of the main body, and the respective excavation bits adjacent to the cutter rotation center direction are not arranged on the same line parallel to the cutter rotation center direction when the horizontal rotation shaft is viewed from the front. It is characterized by having a step of excavating a face with a drilling cutter and a step of adding plastics to the excavated sediment and stirring and plasticizing the excavated sediment with a paddle screw in a chamber behind the drilling cutter. .

In the present invention, the additive material is added to the earth and sand excavated by rotating a plurality of excavation cutters, and the mixture is sufficiently agitated by a paddle screw provided in a chamber behind the excavation cutter to be plastically fluidized and discharged. By doing so, the earth pressure in the chamber can be equalized, and the face during excavation can be held in a stable state. That is, the excavation cutter and the paddle screw are arranged with their respective rotation axes in parallel and the axial directions thereof are oriented in the tunnel width direction, and the amount of excavated soil taken into the chamber is constant over the entire tunnel width. The excavated earth and sand are evenly agitated in the entire axial direction, and the pressure difference of earth pressure in the chamber can be reduced.
Further, a plurality of excavation cutters are provided, and more effective agitation can be performed by arranging the paddle screws so as to correspond to the excavation cutters at each stage.

In the tunnel excavator according to the present invention, the rotation shaft diameter of the excavation cutter includes a large-diameter rotation shaft and a small-diameter rotation shaft that change in the direction of the rotation shaft, and the small-diameter rotation shaft is open compared to the large-diameter rotation shaft. It is preferable that the area is large .

In the present invention, it is possible to hold the ground of the face with the large diameter portion of the rotating shaft and increase the intake of excavated earth and sand with the small diameter portion. In other words, the large-diameter portion of the rotating shaft has a smaller opening area when viewed from the front with respect to the chamber behind the excavation cutter, so that the amount of sand taken into the chamber is smaller than that of the small-diameter portion, and the face is stabilized. be able to.
On the other hand, since the small-diameter portion of the rotating shaft has a large opening area, it is possible to increase the amount of excavated soil and increase the excavation efficiency.

  In the tunnel excavator according to the present invention, it is preferable that the rotation shaft diameter of the excavation cutter is smaller in the central portion than in the both sides in the rotation shaft direction.

  In the present invention, since the face surface is likely to collapse on both sides in the tunnel width direction, the face surface is arranged with the large diameter rotation shaft by disposing the large diameter portion (large diameter rotation shaft) of the excavation cutter at both ends thereof. The area to be suppressed is increased, and the excavation efficiency is increased as a small-diameter portion (small-diameter rotation shaft) in the central portion in the rotation axis direction. In other words, the face face is prevented from collapsing and the excavation efficiency is increased.

  Moreover, in the tunnel excavator according to the present invention, it is preferable that the excavation cutter is divided into a plurality of pieces in the direction of the rotation axis, and each can rotate independently.

  In the present invention, each of the divided excavation cutters can be adapted to various excavation methods, and excavation can be performed while changing the rotation speed. For example, excavation can be performed by increasing the rotation speed on only one side in the tunnel width direction. By increasing the efficiency, the direction of the tunnel excavator can be changed.

  Further, in the tunnel excavator according to the present invention, the uppermost excavation cutter is provided in an inner cylinder provided so as to protrude toward the face in the outer cylinder of the excavator body, and is provided in a chamber inside the inner cylinder. A paddle screw is preferably provided.

  In the present invention, by causing the inner cylinder to protrude with respect to the outer cylinder and excavating the uppermost excavation cutter in advance of the excavation cutter below the uppermost stage, it is possible to suppress the collapse of the natural ground, The face can be stabilized.

  According to the tunnel excavator and the tunnel excavation method of the present invention, the earth pressure in the chamber is equalized and the pressure difference is reduced by agitating the excavated earth and sand and plasticizing it in the entire axial range of the paddle screw. can do. Thereby, the face can be stabilized and the occurrence of land subsidence due to the influence of a partial decrease in earth pressure can be suppressed.

It is a side view which shows schematic structure of the tunnel excavator by embodiment of this invention. It is the figure which looked at the upper side excavation part of the tunnel excavator shown in FIG. 1 from the top. It is a front view of the tunnel excavator shown in FIG. (A)-(d) is a figure which shows the excavation procedure by a tunnel excavator.

  Hereinafter, a tunnel excavator and a tunnel excavation method according to embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1 and FIG. 2, the tunnel excavator 1 according to the present embodiment is necessary for tunnel excavation inside the excavator body 2 in accordance with the cross-sectional shape of the tunnel to be built in substantially the same manner as a normal shield machine. It accommodates almost all kinds of various equipments, digs a natural ground, assembles a segment behind it, and digs it with reaction force from the segment. Furthermore, this tunnel excavator 1 is excavated by rotating the cutter (excavation cutter 5), and the excavated soil is added with a mud material (additive material) such as a bubble material or bentonite, and is agitated and plasticized. This is a so-called “mud pressure shield excavator”, which is a excavation method for taking in excavated soil.
Here, in the following description, the left and right directions on the paper surface in FIGS. 1 and 2 are defined as “front-rear direction X”, the face side is “front”, and the opposite side is “rear”. The direction from the rear to the front is defined as “digging direction X1”.

Specifically, the excavator body 2 includes an outer cylinder 3 formed of a rectangular cylindrical skin plate that matches the cross-sectional shape of the tunnel to be excavated, and an assembled segment (not shown) is provided in the outer cylinder rear portion 3b. A plurality of propulsion jacks 4, 4,... For pushing and propelling from the reaction force are provided on the ring girder 31 described later. The excavator body 2 according to the present embodiment has a substantially square cross-sectional shape as viewed from the face side.
In addition, the excavator main body 2 is provided with an erector device (not shown) for use in assembling the segments, as well as devices necessary for tunnel excavation. explain.

  On the inner side of the outer cylinder 3, a ring girder 31 provided in the outer cylinder body 3c, and an upper and lower partition that vertically divides the inside of the outer cylinder 3 in front of the ring girder 31 into an upper excavation part M1 and a lower excavation part M2. A wall 32 is provided. And, in front of each of the upper excavation part M1 and the lower excavation part M2, excavation cutters 5 (5A, 5B, 5C) for excavating the face into a rectangular cross section are provided.

  The upper excavation part M1 is surrounded by the outer cylinder 3 and the upper and lower partition walls 32, and an inner cylinder 6 having a horizontally long rectangular cross-sectional shape in a front view is provided so as to be able to advance and retreat in the front-rear direction X. The upper excavation part M1 arranges the excavation cutter 5 (upper cutter 5A, which will be described later) in front of the space of the inner cylinder 6, and the paddle screw 7 (7A) for agitating excavated earth and sand behind the upper cutter 5A. It has a configuration with. A partition wall 61 is provided behind the paddle screw 7A.

  Further, the lower excavation part M2 is surrounded by the outer cylinder 3 and the upper and lower partition walls 32, and a partition wall 33 is provided on the rear side to support a middle cutter 5B and a lower cutter 5C described later from the rear. This lower excavation part M2 arranges excavation cutters 5 (a middle cutter 5B and a lower cutter 5C, which will be described later) in front of the space of the excavator main body 2, and digs earth and sand behind the middle cutter 5B and the lower cutter 5C. The paddle screw 7 (7B) for stirring is provided.

Here, the excavation cutters 5 (5A, 5B, 5C) disposed in the outer cylinder front portion 3a of the outer cylinder 3 each have a cylindrical shape with a cutter bit on the peripheral surface, and the tunnel width in the direction of the cutter central axis O1. The direction of rotation and its axis of rotation extend over almost the entire tunnel width. The excavation cutters 5A, 5B, and 5C are arranged in a vertical direction and have a plurality of stages (three stages in the present embodiment), and a tunnel having a rectangular cross section is excavated as a whole.
In addition, the upper cutter 5A (the uppermost cutter) located at the uppermost stage can move forward and backward in the front-rear direction X with respect to the outer cylinder 3 together with the inner cylinder 6. On the other hand, the middle-stage cutter 5B and the lower-stage cutter 5C are fixed to the partition wall 33 in the outer cylinder 3 via the support arm 12, and are configured to move together with the outer cylinder 3 in the digging direction X1 by the propulsion jack 4.

  The three-stage excavation cutter 5 (5A, 5B, 5C) is arranged so that the upper-stage cutter 5A is positioned forward in the front-rear direction X, that is, the lower-stage cutter 5C, the middle-stage cutter 5B, and the upper-stage cutter 5A. It is placed in the overhang position.

First, the structure of the upper excavation part M1 excavated by the upper cutter 5A will be described with reference to FIG.
The inner cylinder 6 provided in the upper excavation part M1 includes a partition wall 61 that divides the front and rear spaces inside, and an advance / retreat jack 9 is provided between the partition wall 61 and the ring girder 31 positioned behind the partition wall 61. The jack 9 can be extended and retracted in the front-rear direction X within a range longer than the length of one digging length. And the inner cylinder 6 becomes a structure which moves in a liquid-tight state with respect to the outer cylinder 3 which forms the upper excavation part M1.

The inner cylinder 6 has a space on the face side of the partition wall 61 for taking in the earth and sand excavated by the upper cutter 5A and agitating with the paddle screw 7 (7A) to discharge the soil, that is, a chamber (first chamber R1) and It has become.
An opening 61a in which an intake port 8a of a soil removal screw 8A described later is disposed is provided at the center lower portion of the partition wall 61 in the tunnel width direction. On the face side of the partition wall 61, a slope 61b that gradually extends forward from the opening 61a toward both sides in the tunnel width direction is formed. An appropriate number of earth pressure gauges 11 for measuring the earth pressure in the first chamber R1 are provided on the slope 61b of the partition wall 61.

  The upper end of the inner cylinder 6 is provided with a hood 62 that extends toward the face and covers the upper part of the upper cutter 5A. The hood 62 is provided with a cutting edge 62a at the tip on the face side.

  The upper cutter 5A is arranged in a state of projecting to the face side from the inner cylinder 6, and is supported rotatably about the cutter center axis O1 by a pair of support arms 10 and 10 extending from the partition wall 61 toward the face side. ing. Each support arm 10 is provided so as to pivotally support a position between a pair of large-diameter rotary shafts 52 disposed on both sides in the axial direction of a small-diameter rotary shaft 52, which will be described later, so as not to interfere with the paddle screw 7A.

  As shown in FIG. 3, the support arm 10 is provided with a passage (not shown) of mud clay material to be added to the excavated soil, and is provided in the vicinity of the cutter rotating shaft support portion on the face side. It has a structure in which mud-soil material such as bubble material and bentonite is discharged from the discharge port 13 toward the face.

  As shown in FIGS. 2 and 3, the upper cutter 5A is arranged with the direction of the central axis O1 in the tunnel width direction (direction along the facet) and in the horizontal direction. The excavation cutter 5 has a configuration in which the large-diameter rotary shafts 51 are arranged on both sides in the axial direction, and the small-diameter rotary shafts 52 smaller in diameter than the large-diameter rotary shaft 51 are coaxially arranged at the axial center. Yes. Specifically, two large-diameter rotary shafts 51 and 51 are arranged on both sides of the small-diameter rotary shaft 52 in the rotational axis direction, respectively, and further, the support arm 10 described above between the large-diameter rotary shafts 51 and 51. It is supported rotatably. The upper cutter 5A may be a large-diameter rotating shaft over the entire axial direction.

  A plurality of cutter bits 53 and 54 (excavation bits) projecting in the radial direction of the rotation shaft are provided on the peripheral surfaces of the rotation shafts 51 and 52, respectively, and all the cutter bits 53 in a plane orthogonal to the rotation shaft are provided. , 54 have substantially the same rotational trajectory. That is, the cutter bit 53 provided on the large-diameter rotating shaft 51 is smaller in height than the cutter bit 54 of the small-diameter rotating shaft 52.

A drive motor (not shown) is incorporated in each large-diameter rotating shaft 51, and each rotating shaft 51 is configured to rotate independently. The central small-diameter rotating shaft 52 is connected to one adjacent large-diameter rotating shaft 51 and rotates together with the large-diameter rotating shaft 51. Thereby, it becomes possible to adapt each large-diameter rotating shaft 51 to various excavation methods and excavate by changing the rotation speed. For example, the excavation efficiency can be increased by increasing the rotation speed only on one side in the tunnel width direction. The direction of the excavator body 2 can be changed by raising.
In addition, a drive motor is provided in one of the four large-diameter rotary shafts 51, and the large-diameter rotary shaft 51 and the small-diameter rotary shaft 52 are connected and fixed, so that all the rotary shafts 51 of one excavation cutter are provided. , 52 can be rotated.

  Further, the upper cutter 5A is rotated in a direction (arrow E1 direction in FIG. 1) that is scraped from the top to the bottom with respect to the face, so that the direction of the cutter bits 53 and 54 is at a position in contact with the face. The rotary shafts 51 and 52 are fixed so as to face downward.

  Next, as shown in FIG. 2, the paddle screw 7A disposed in the chamber R1 at the rear of the upper cutter 5A is for adding a mud material to the soil excavated by the excavating cutter 5A and stirring the screw. The central axis O2 of the shaft 71 is arranged in parallel (also parallel in the present embodiment) with the central axis O1 of the rotating shafts 51 and 52 of the upper cutter 5A. The screw rotating shaft 71 includes a plurality of agitators having a predetermined shape at an appropriate position on the circumferential surface of the rotating shaft 71 while supporting portions 71 a and 71 a at both ends in the axial direction are rotatably supported by the side wall 63 of the inner cylinder 6. Wings 72, 72, ... are arranged.

  Here, the side wall 63 is provided with a drive motor 73 on the rear side of the partition wall 61. And the support part 71a of the screw rotating shaft 71 is rotationally driven by the drive motor 73 through the transmission means of the drive chain 74 provided inside the side wall part 63.

  Furthermore, a soil removal screw 8 (8A) is provided in the opening 61a of the partition wall 61 in a state where the intake port 8a is disposed in the first chamber R1. That is, the excavated earth and sand agitated by the paddle screw 7A is discharged to the rear of the excavator body 2 by the earth discharging screw 8A.

Next, the lower excavation part M2 excavated by the middle cutter 5B and the lower cutter 5C will be described with reference to FIG. In addition, the thing similar to the structure of the upper excavation part M1 mentioned above is demonstrated using FIG.
The lower excavation part M2 is located below the upper and lower partition walls 32 of the outer cylinder front part 3a as described above, and a partition wall 33 is provided on the front side of the ring girder 31, and the space on the face side of the partition wall 33 is It is a chamber (second chamber R2) for taking in the earth and sand excavated by the middle cutter 5B and the lower cutter 5C, and stirring and discharging the soil.

  An opening 33a in which an intake port 8a of a soil removal screw 8B, which will be described later, is disposed is provided at the center lower portion in the tunnel width direction as viewed from the face side of the partition wall 33. Further, on the face side of the partition wall 33, a slope (not shown) (similar to the slope 61b of the upper excavation part M1 shown in FIG. 2) is formed which gradually extends forward from the opening 33a toward both sides in the tunnel width direction. Yes. An appropriate number of earth pressure gauges (not shown) for measuring the earth pressure in the second chamber R2 are also provided on the slope of the partition wall 33.

  The middle-stage cutter 5B and the lower-stage cutter 5C are supported rotatably about the cutter center axis O1 by a pair of support arms 12 and 12 extending from the partition wall 33 toward the face. As shown in FIG. 2, each support arm 12 supports a position between a pair of large-diameter rotary shafts 52 disposed on both sides in the axial direction of the small-diameter rotary shaft 52. An opening is provided in the arm portion so as not to interfere with the paddle screw 7B located behind 5C, and the rotation shaft of the paddle screw 7B is penetrated.

  Further, as shown in FIG. 3, the supporting arms 12 and 12 are provided with a mud clay material passage (not shown) for adding to the excavated earth and sand, in the vicinity of the cutter rotating shaft support part on the face side. The mud clay material is discharged toward the face from the discharge port 13 provided on the surface.

  The middle-stage cutter 5B and the lower-stage cutter 5C have the same configuration as the above-described upper-stage cutter 5A except for a part of the configuration (the rotation direction and the direction of the cutter bit), and therefore a configuration different from the upper-stage cutter 5A will be described. That is, the middle-stage cutter 5B and the lower-stage cutter 5C are rotated in a direction (arrow E2 direction, E3 direction in FIG. 1) that is scraped from the bottom to the top with respect to the face surface. The claw is fixed to the rotary shafts 51 and 52 so that the direction of the claw is upward at the position in contact with the rotary shaft 51.

Then, in the second chamber R2 behind the upper and lower two cutters of the middle cutter 5B and the lower cutter 5C, the screw center axis O2 is parallel to the center axis O1 of both cutters 5B, 5C (also parallel in this embodiment). A paddle screw 7 (7B) facing toward is rotatably supported on the side portion of the outer cylinder 3.
Since the configuration of the paddle screw 7B is the same as that of the paddle screw 7A of the upper excavation part M1 shown in FIG. 2, detailed description thereof is omitted here.

  Furthermore, a soil removal screw 8 (8B) is provided in the opening 33a of the partition wall 33 in a state where the intake port 8a is disposed in the second chamber R2. That is, the excavated earth and sand stirred by the paddle screw 7A is discharged to the rear of the excavator body 2 by the earth discharging screw 8B.

Next, a tunnel excavation method by the tunnel excavator 1 described above will be described with reference to FIG. Note that FIG. 4 partially shows the configuration of each part and simplifies it for easy viewing.
First, as shown to Fig.4 (a), it excavates, making the upper stage cutter 5A protrude in the face side (excavation direction X1) in the upper excavation part M1. Specifically, the natural ground of the face is excavated by the rotation of the upper cutter 5 </ b> A while the forward and backward jack 9 between the partition wall 61 and the ring girder 31 is extended to propel the inner cylinder 6. At this time, the mud material injected from the discharge port 13 provided at the tip of the support arm 10 shown in FIG. 3 is added to the excavated soil, and the excavated soil is sufficiently stirred by the paddle screw 7A in the first chamber R1. After that, it is carried out from the soil removal screw 8 </ b> A to the rear of the excavator body 2.
When the inner cylinder 6 is propelled, the outer cylinder 3 is not moved in the fixed position, and the middle cutter 5B and the lower cutter 5C are also stopped.

 Next, when the excavation of a predetermined excavation length is completed in the upper cutter 5A, as shown in FIGS. 4B and 4C, while rotating the middle cutter 5B and the lower cutter 5C in the lower excavation part M2, The propulsion jack 4 between the ring girder 31 and the segment S is extended, and the outer cylinder 3 is advanced in the excavation direction X1 for excavation. At this time, the mud material injected from the discharge port 13 provided at the tip of the support arm 12 shown in FIG. 3 is added to the excavated soil, and the excavated soil is sufficiently stirred by the paddle screw 7B in the second chamber R2. After that, it is carried out from the soil removal screw 8B to the rear of the excavator body 2.

  During the excavation in the lower excavation part M2, excavation by the upper cutter 5A is stopped, and the position of the inner cylinder 6 is also fixed. However, since the outer cylinder 3 is advanced by the propulsion jack 4 during excavation by the lower excavation part M2, the advance / retreat jack 9 is contracted to synchronize with the forward movement of the outer cylinder 3.

  Then, as shown in FIG. 4D, when excavation for one cycle is completed by the three stages of the excavation cutters 5A, 5B, and 5C, the propulsion jack 4 extended while assembling the segment S is returned and one cycle of excavation is performed. The excavation is completed. Thus, in this tunnel excavation method, the inner cylinder 6 is protruded with respect to the outer cylinder 3, and the upper cutter 5A is excavated ahead of the middle cutter 5B and the lower cutter 5C, thereby suppressing the collapse of the natural ground. And can stabilize the face.

Next, the operation of the tunnel excavator 1 described above will be described based on the drawings.
First, as shown in FIGS. 1 to 3, in the present tunnel excavator 1, a mud material is added to the earth and sand excavated by rotating a plurality of stages of excavation cutters 5 (5A, 5B, and 5C). The earth pressure in the chambers R1 and R2 can be equalized by sufficiently agitating with the paddle screws 7A and 7B provided in the chambers R1 and R2 at the rear of the plate 5 and plastic fluidizing and discharging the soil. The face during excavation can be held in a stable state.

That is, the excavation cutter 5 and the paddle screw 7 are arranged with their respective rotation axes (the cutter central axis O1 and the screw central axis O2) in parallel, and the axial directions thereof are directed in the tunnel width direction, and taken into the chambers R1 and R2. Since the amount of excavated soil is constant over the entire tunnel width, the excavated soil is evenly agitated over the entire axial direction of the paddle screw 7, and the pressure difference between the earth pressures in the chambers R1 and R2 can be reduced.
Moreover, in this tunnel excavator 1, more effective agitation can be performed by arranging the paddle screws 7A and 7B so as to correspond to the plural stages of excavation cutters 5A, 5B, and 5C.

  Further, in the tunnel excavator 1 according to the present invention, the rotation shaft diameter of the excavation cutter 5 changes in the rotation axis direction, and the large-diameter rotation shaft of the excavation cutter 5 is disposed on both sides in the tunnel width direction where the face surface is likely to collapse. By arranging 51, the area for suppressing the facet with the large-diameter rotating shaft 51 is increased. Therefore, compared to the small-diameter rotating shaft 52 arranged at the center in the direction of the rotating shaft, Collapse can be suppressed.

  As described above, in the tunnel excavator and the tunnel excavation method according to the present embodiment, the earth pressure in the chambers R1 and R2 is reduced by stirring and excavating the excavated earth and sand within the range of the entire paddle screw 7 in the axial direction. The pressure difference can be reduced by equalization. Thereby, the face can be stabilized and the occurrence of land subsidence due to the influence of a partial decrease in earth pressure can be suppressed.

Although the embodiments of the tunnel excavator and the tunnel excavation method according to the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.
For example, in the present embodiment, the upper cutter 5A is provided in the inner cylinder 6 that can be advanced and retracted, and the upper cutter 5A is projected in advance, so that the upper excavation part M1 excavates a small section first. Although it was set as the excavation procedure to perform, it is not limited to such a tunnel excavation method. For example, if the natural ground is not a collapsible natural ground, the upper excavation part M1 and the lower excavation part M2 may be excavated simultaneously. That is, the tunnel excavator 1 may have a configuration in which the inner cylinder 6 is not provided. In this case, the upper and lower partition walls 32 of the outer cylinder 3 may be omitted to constitute one chamber.
The number of excavation cutters 5 is not limited to three as in the present embodiment. In short, it is only necessary to provide two or more stages of excavation cutters, which can be arbitrarily set according to the size and shape of the tunnel excavation cross section.

In this embodiment, the excavation cutter 5 is divided into a plurality of parts along the axial direction, a large-diameter rotary shaft 51 is arranged on both sides in the rotational axis direction, and a small-diameter rotary shaft 52 is arranged in the center in the axial direction. However, the present invention is not limited to such a structure.
In other words, any configuration may be used as long as the rotation shaft diameter of the excavation cutter 5 changes in the rotation axis direction. In this case, the size of the rotation shaft diameter of the excavation cutter 5 can be changed in accordance with the natural ground to be excavated. It is possible to hold the ground of the face with the large diameter part of the rotating shaft and increase the intake of excavated soil at the small diameter part. For example, as in the present embodiment, in the case of a natural ground where the amount of excavated earth and sand is to be suppressed, the ratio of the large-diameter portion (large-diameter rotary shaft 51) of the rotary shaft to the small-diameter portion (small-diameter rotation) By making it larger than the shaft 52), the opening area as viewed from the front with respect to the chamber behind the excavation cutter 5 is reduced, so that the amount of sand taken into the chamber is smaller than that of the small diameter portion, and the face is stabilized. Can be planned. On the other hand, in the case of a self-supporting ground such as viscous soil, by increasing the ratio of the small-diameter portion of the rotating shaft, the amount of excavated sediment can be increased and the excavation efficiency can be increased.

Further, the diameter of the rotary shaft of the excavation cutter 5 is two or more in the axial direction (the large diameter rotary shaft 51 and the small diameter rotary shaft 52) as in the present embodiment. It is also possible to adopt a configuration in which the rotational axis of the diameter is gradually changed step by step.
Furthermore, it is not restricted to arrange | position the small diameter rotating shaft 52 in the rotating shaft direction center part like this Embodiment.
Furthermore, the number of axial divisions of the one-stage excavation cutter 5 can also be set arbitrarily, and a cutter that is not divided may be used.

  Further, the configuration of the outer diameter dimension, the axial length dimension, the mounting position, the quantity, etc. of the excavation cutter 5 and the paddle screw 7 is not limited to the present embodiment, and the ground condition and tunnel to be excavated It can be appropriately set according to conditions such as the size of the cross section.

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

DESCRIPTION OF SYMBOLS 1 Tunnel excavator 2 Excavator body 3 Outer cylinder 4 Propulsion jack 5 Excavation cutter 5A Upper cutter (upper excavation cutter)
5B Middle cutter 5C Lower cutter 6 Inner cylinder 7, 7A, 7B Paddle screw 8, 8A, 8B Earth removal screw 9 Advance / retreat jack 10, 12 Support arm 13 Discharge port 51 Large diameter rotary shaft 52 Small diameter rotary shaft 53, 54 Cutter bit ( Drilling bit)
M1 Upper excavation part M2 Lower excavation part O1 Cutter central axis O2 Screw central axis

Claims (6)

A tunnel excavator that excavates with a cutter on the face side of the excavator body,
A drilling bit is provided around the horizontal rotary shaft so as to project outward at a predetermined interval in the axial direction, and a drilling cutter arranged with the axial direction facing the tunnel width direction extends along the front surface of the excavator body. Multiple stages are provided in the vertical direction,
In the vicinity of the excavation cutter, there is provided a discharge port for the additive material that plastically fluidizes the excavated earth and sand,
In the chamber behind the excavation cutter, a paddle screw that stirs excavated soil and plastically fluidizes it is provided with its screw rotation axis parallel to the rotation axis of the excavation cutter ,
Each of the excavation cutters includes a plurality of the excavation bits, and the respective excavation bits adjacent to the cutter rotation center direction are not arranged on the same line parallel to the cutter rotation center direction when the horizontal rotation axis is viewed from the front. Tunnel excavator characterized by that. The rotating shaft diameter of the excavation cutter is composed of a large diameter rotating shaft and a small diameter rotating shaft that change in the rotating shaft direction ,
The tunnel excavator according to claim 1, wherein the small-diameter rotating shaft has a larger opening area than the large-diameter rotating shaft .   3. The tunnel excavator according to claim 2, wherein the rotation shaft diameter of the excavation cutter is smaller in diameter at the center than at both sides in the rotation axis direction.   The tunnel excavator according to any one of claims 1 to 3, wherein the excavation cutter is divided into a plurality of pieces in the direction of the rotation axis, and each can be rotated independently. The uppermost excavation cutter is provided in an inner cylinder provided so as to protrude toward the face in the outer cylinder of the excavator body,
The tunnel excavator according to any one of claims 1 to 4, wherein the paddle screw is provided in a chamber inside the inner cylinder. Excavation bits project outward at predetermined intervals in the axial direction around the horizontal rotary shaft, and are arranged with the axial direction facing the tunnel width direction. A plurality of vertical excavators are arranged along the front surface of the excavator body. A step of excavating a face with a drilling cutter that is provided in steps and each of the drilling bits adjacent to the cutter rotation center direction is not arranged on the same line parallel to the cutter rotation center direction when the horizontal rotation axis is viewed from the front ;
A process of adding the additive to the excavated earth and sand, and agitating the excavated earth and sand with a paddle screw in the chamber behind the excavated cutter, and plastic fluidizing;
A tunnel excavation method characterized by comprising:

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