JP3869522B2 - How to start a shield machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a starting method shielded-excavator, it relates starting method of shield machine when drilling shield tunnel in particular steep curve linear shape section.
[0002]
[Prior art]
In excavation work for a shield tunnel, a start shaft is constructed with a retaining wall such as a continuous underground wall at the starting point of the tunnel section, and a shield excavator is started from within this start shaft. The shield machine is installed on the starting stand installed at the bottom of the starting shaft, and starts from the starting stand through the starting opening provided in a part of the retaining wall to start to the ground. .
[0003]
FIG. 9 is a front view showing a configuration of a starter 50 for a shield machine installed in a conventional starter shaft. The start stand 50 shown in the figure is installed on the floor slab concrete 62 so that the direction of the shield machine 60 coincides with the tunnel axis. An ordinary start stand 50 is manufactured by assembling a shape steel material such as an H-shaped steel into a box shape. A cradle 51 that directly supports the shell (skin plate) of the shield machine 60 is provided on both side ends of the upper surface of the starter base 50. A temporary rail 52 made of a light rail or a plurality of round steel bars is fixed to the inclined surface of the cradle 51 along the tunnel axis direction. The shield machine 60 is line-supported in the tunnel axis direction by two temporary rails 52 at separate positions. Further, the shield machine 60 advances while the shell is sliding on the temporary rail 52 when starting.
[0004]
By the way, the tunnel alignment in the start shaft is generally designed in a straight line so as to start crossing the retaining wall at a right angle when the shield machine starts. For example, as shown in FIG. 10, the start shaft 70 is constructed before the start position of the curve section 72, and the shield construction machine 60 started from the start shaft 70 is curved immediately after the entire shield machine 60 completely enters the ground. Is to be done. The excavation in the curved section 72 is achieved by adjusting the amount of propulsion stroke in the left-right direction of the shield jack (not shown) of the shield machine 60.
[0005]
[Problems to be solved by the invention]
However, in the case of shield tunnels that excavate underground parts of urban areas, it may be necessary to install start shafts in curved tunnel sections due to route design or ground construction space. For example, as shown in FIG. 11, when a part of the curved section 72 is already constructed by the excavation tunnel 73 and the excavation tunnel 73 and the shield tunnel 74 are switched at the boundary of the construction zone, the start shaft is generally located at the illustrated position. 70 is built. Since the shield machine 60 starting from the start shaft 70 can start only in the tangential direction of the curved tunnel as indicated by the arrow X, the direction and design of the shield machine 60 immediately after starting from the start shaft 70 are designed. An error Δ occurs between the upper tunnel line shape and the upper tunnel line shape. When the curved section 72 is designed to be a sharp curve with a small radius, the meandering operation is continued while excavating until this error Δ is absorbed. For this reason, there arises a problem in assembling the segments or the like, and there is a possibility that the cross section of the design tunnel cannot be secured when the amount of meandering is large. There is also a problem that the amount of excavation of the natural ground increases due to the excavation. It is an object of the present invention to solve the problems of the prior art described above, to provide a starting method of shield machine was set to start from the starting pit built steeper curve tunnel section is possible There is.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention can be separated into a plurality of blocks arranged along the tunnel axis direction, and on a starting base of a frame structure having a support body that is slidable with respect to an installed floor surface. The entire shield machine before the start is placed, and the block of the part that is no longer placed due to the forward movement of the shield machine when the shield machine is excavated to the ground side is separated, and the shield machine depending on the deflection operation is performed by the direction adjusting propulsion means having the shield machine of the tail portion, mounted to said by starting base along a steep curve shape of the tunnel line is slid the shield machine It is characterized by starting.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a starting method for a shield machine according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view showing a shield machine starter base 10 (hereinafter referred to as starter base 10) used in the present invention. As shown in the figure, the start stand 10 is slidably installed on the floor steel plate 3 laid on the floor slab concrete 2 of the start shaft. The starting platform 10 has a frame structure in which two support beams 11 arranged along the tunnel axis direction and a plurality of horizontal beams 12 connecting the two support beams 11 are connected. The entire starter base 10 is point-supported on the floor steel plate 3 at positions of ball wheels 20 as a plurality of supports provided at the lower surface of the support beam 11.
[0010]
FIG. 2 is a schematic plan view of the starter 10 viewed from above. In the figure, the shield machine 4 temporarily placed on the support beam 11 of the start table 10 is indicated by a virtual line. Each support girder 11 is bolted at two locations indicated by triangular symbols. That is, the end plates 11a of the support girders 11 are surface-joined by a plurality of bolts 15 (see FIG. 3). When the connection by the bolt 15 is released, the starter base 10 can be divided into three blocks arranged along the tunnel axis direction as a whole. (Hereinafter, when distinguishing each block, it is written as No. 1 start-up base to No. 3 start-up base from the head side of the shield machine 4). Are connected by Further, seven ball wheels 20 are attached to the lower surface of one integrated support beam 11 as indicated by broken lines. The integrated starter base 10 is applied with a predetermined external force by a rolling action of a fulcrum ball 25 (described later) in the ball wheel 20 even when the shield machine 4 is temporarily placed. Slide up. Note that stiffening ribs 14 are provided at the support positions of the ball wheels 20 on the side surfaces of the support beam 11 as shown in FIG. This stiffening rib 14 prevents partial deformation of the support beam 11 and reliably transmits the load of the shield machine 4 to each ball wheel 20.
[0011]
FIG. 4 is a partial front view showing a connecting portion of the support beam 11 and the cross beam 12. As shown in the figure, the support girder 11 is an assembly box girder in which a plurality of sections and plates are welded together, and a ball wheel 20 is attached to the lower surface thereof. Further, in the ball wheel 20, a ball receiving metal 21 that houses the fulcrum ball 25 is incorporated. As shown in FIG. 5, a ball receiving recess 22 is formed on the lower surface of the ball receiving metal 21, and a ring-shaped groove 23 is formed on the upper surface of the ball receiving recess 22. The fulcrum ball 25 is rotatably accommodated in the ball receiving recess 22 while being point-contacted supported by eight receiving balls 24 (only two are shown in FIG. 5) accommodated in the ring-shaped groove 23. Has been. In this embodiment, the fulcrum ball 25 has a diameter of 120 mm, and the receiving ball 24 has a diameter of 32 mm. As these materials, high carbon chrome bearing steel is used, but various materials can be applied as long as they are metal spheres having such a hardness that the spherical surface is not crushed when loaded. Further, the fulcrum ball 25 is smoothly rotated by the eight receiving balls 24 housed in the ball receiving recess 22. Further, in order to prevent the fulcrum ball 25 from falling off, a ball pressing plate 26 is fixed to the lower surface of the ball receiving metal 21 with a countersunk bolt 27.
[0012]
On the other hand, a temporary rail 17 made of two round steel bars arranged in the tunnel axis direction is fixed to the cradle 16 on the upper surface of the support beam 11 in the same manner as the conventional starter base 10. As a result, the shield machine 4 is line-supported on the temporary rail 17 as shown in FIG. In the present embodiment, as shown in FIG. 1, the temporary rail 17 is disposed at a position that forms a deflection angle α from the center of the shield machine 4. Moreover, the temporary rail 17 functions also as a slide rail for making the shield machine 4 slide forward like the past.
The upper surface flange 12 a of the cross beam 12 that connects the two support beams 11 is manufactured in a concave shape with a curvature along the outer shape of the shield machine 4.
[0013]
Next, a procedure for starting the shield machine 4 temporarily placed on the start table 10 as shown in FIG. 2 in the tangential direction of the sharp curve set from the start shaft 70 will be described with reference to FIG. In the following description, the starter base 10 is designated by the reference number. Each block is shown separately as 1 to 3 starters.
First, as shown in FIG. 6A, the temporary assembly segments 41 for three rings are assembled on the tail side of the shield machine 4 before starting. When the shield machine 4 is started, the propulsive force of the shield machine 4 is supported on a reaction table (not shown) via the temporary assembly segment 41. At this time, the starting opening 71a in the traveling direction of the shield machine 4 is closed by a temporary wall 45 that can be easily crushed, such as a soil cement wall, instead of the normal retaining wall 40. The shield machine 4 starts into the natural ground 75 while crushing the temporary wall 45 of the start opening 71a. A ring-shaped wellhead concrete 42 is constructed around the start opening 71a. Further, a known entrance packing 44 is attached to the inner peripheral edge of the wellhead concrete 42 via a flap 43. When the shield machine 4 passes through the start port 71a, the entrance packing 44 portion is in close contact with the shell (skin plate), and the watertightness between the two is maintained. When the shield machine 4 is further advanced from this state, the tip of the shield machine 4 advances from the start port 71a to the ground 75 side. As shown in FIG. No. 3 after passing on the 3rd starting platform. 3 starters and No. Separated from the two starters. From this stage, the right and left (upper and lower as required) shield jacks (not shown) of the shield machine 4 are adjusted to start the curve construction. The shield excavator can deflect the entire excavation direction slightly with the position of the wellhead concrete 42 as a fulcrum S (indicated by ▽ in the figure). By continuing the excavation in this state, as shown in FIG. 5C, the No. 1 supporting the tail portion 4a of the shield excavator 4 is obtained. 1, no. The two starting platforms slide on the floor steel plate 3 in the direction of arrow A by the operation of the ball wheel 20. In addition, it is preferable that the taper segment T is appropriately incorporated in order to maintain the curved shape by mixing with the standard segment S as the shield machine 4 progresses. In this state, the tail portion 4a of the shield machine 4 is no. No. 2 after passing on the starting platform. 2 starters and No. 2 Separate from the starting platform. In this state, only the tail portion 4a of the shield machine 4 is No. It is in a state of being supported by one starter. Further, when the curve operation is performed, the yawing amount of the shield machine 4 at the fulcrum S of the wellhead concrete 42 is increased in addition to the difference between the left and right propulsion stroke amounts of the shield machine 4. As a result, the shield machine 4 can easily deflect the digging direction to the tangential direction of the initially set sharp curve when the tail portion 4a reaches the start opening 71a.
[0014]
7 is the same as that shown in FIG. 1-No. It is the schematic diagram which accumulated and showed an example of the moving amount | distance of 3 starters. As shown in the figure, when starting on the starter base 10 of the present invention while controlling the propulsion stroke amount of the shield jack of the shield machine, the No. 1 is separated as the shield machine 4 advances. 1-No. By the individual sliding movements of the three starters 10, the shield machine 4 can deflect the excavation direction by an angle θ in the target direction when the entire shell enters the ground from the start shaft. This deflection angle θ is the amount of movement δ in the traveling direction (X) between the blocks (12, 23) and the direction perpendicular to the traveling direction (Y) at the stage where each starting block slides (the movement of each part in FIG. 7). The quantity is distinguished by a subscript.) And the total length of the shield machine.
[0015]
FIG. 8 shows a modification as a slide moving mechanism of the starter base. FIG. 5A shows a sliding rod 31 made of a tetrafluoroethylene resin plate known by the trade name Teflon (registered trademark) instead of the ball wheel, and a slide plate 31 made of the same material in a predetermined range of the floor steel plate 3. A modified example is shown. As shown in the figure, the slide rod 31 of the support beam 20 smoothly slides on the slide plate 31 and the starter base 10 moves. Further, as shown in FIG. 2B, a sealing ring 33 having an open lower surface is provided on the lower surface of the support beam 11, the inside thereof is filled with grease 34, and the shield machine 4 is loaded via the pump 35. Thus, a sliding rod is constructed in which the grease 34 is supplied into the sealing ring 33 at a predetermined pressure. In addition, although not shown in the figure, a manifold with a large number of minute holes is provided at the bottom surface of the support beam, and high-pressure air supplied into the manifold is ejected from the minute holes of the manifold, so that the starting stand is lifted by a minute height. It is also possible to apply an air bed structure which is adapted to be made.
[0016]
As described above, according to the present invention, since the shield machine can be directed in the tangential direction of the predetermined curve when the shield machine has been excavated from the starting vertical shaft to the natural ground side, the direction control of the subsequent curve operation can be performed. Easy to do. In addition, although the description has been given by taking a starter base having three divided blocks as an example, the number of divisions may be two, or four or more may be used to reduce the load burden per piece.
[0017]
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a shield machine starter used in the present invention.
FIG. 2 is a schematic plan view of the starter shown in FIG.
FIG. 3 is a schematic partial side view of the starter shown in FIG. 1;
FIG. 4 is a partially enlarged view showing a state of engagement between a support beam and a horizontal beam of a starter base.
FIG. 5 is an enlarged partial cross-sectional view showing the internal configuration of a ball wheel of a starting stand with a part cut away.
FIG. 6 is a schematic state explanatory view showing a start state from a starter of the shield machine.
FIG. 7 is a schematic explanatory view showing a sliding movement state of the start stand.
FIG. 8 is a partially enlarged view showing a modified example of the starter base.
FIG. 9 is a schematic front view showing a starter of a conventional shield machine.
FIG. 10 is a schematic explanatory view showing a start state from a start shaft of a conventional shield machine.
FIG. 11 is a schematic explanatory view showing a start state from a start shaft of a conventional shield machine.
[Explanation of symbols]
3 Floor steel plate 4 Shield engraving machine 10 Curved part shield encircling machine starter 11 Supporting girder 12 Horizontal girder 20 Ball wheel 25 Supporting point ball

Claims (1)

The entire shield machine before starting is placed on a starting base of a frame structure that can be separated into a plurality of blocks aligned along the tunnel axis direction and has a support that can slide on the installed floor surface. Deflection performed by adjusting the direction of the propulsion means of the shield machine by separating the block of the part that is no longer placed due to the forward movement of the shield machine with the excavation of the shield machine to the ground depending on the operation, the tail portion of the shield machine, characterized in that so as to start the shield machine along a steep curve shape of the tunnel line is slid by the starting base was placed originating advanced method of shield machine.

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