Displacement prevention fixing and releasing method for concrete box body for open shield method

Abstract

To provide a displacement prevention fixing and releasing method for concrete box body for open shield method, which uses a light-weight member capable of being easily, simply and safely installed and removed by an operator.SOLUTION: Curve-shaped sheath holes 33 are installed from haunch faces 43 on four corners of concrete box bodies 4 to be connected so as to continue at connection end faces. A semicircular curve shaped pin 32 is inserted from an opening of one sheath hole 33 so as to make both ends of the pin protrude from the haunch faces 43 and prevent displacement at the connection end faces between the concrete box bodies 4. When displacement prevention becomes unnecessary, the semicircular curve shaped pin 32 is removed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a slip prevention structure for a flexible concrete box used in the open shield construction method for constructing underground structures such as water supply and sewerage systems and underground tunnels in urban areas. [Background technology]

[0002] The open shield method is a highly rational method that takes advantage of the advantages of the open cut method and the shield method, and its outline is explained in Figures 9 to 13.

[0003] In the figure, reference numeral 1 denotes an open shield machine, which is a shield machine having openings on the front, rear and top, and consisting of left and right side wall plates 1a and a bottom plate 1b connected to these side wall plates 1a.

[0004] The open shield machine 1 has cutting edges 2 formed at the tips of the side wall plates 1a and bottom plate 1b, and propulsion jacks 3 are arranged vertically facing rearward in the center or near the rear end of the side wall plates 1a.

[0005] Furthermore, the open shield machine 1 has its body divided into a front machine 17 and a tail machine 18 in the longitudinal direction, and the front end of the tail machine 18 is fitted into the rear end of the front machine 17, forming a center-folding section 51 at the mutual fitting portion, making it bendable. A center-folding jack is provided at this center-folding section 51.

[0006] The front machine 17 mainly serves as an excavation section, and the tail machine 18 has the propulsion jack 3 arranged thereon and serves as a tail section 19 for suspending and setting down the concrete box 4 .

[0007] In the figure, 16a is a sliding earth retaining plate provided at the front end of the front machine 17, and 23 is a press bar (push angle) made of H-shaped steel or the like. 52 is a rear earth retaining plate that is used when the concrete box 4 comes out of the tail machine 18 as the open shield machine 1 excavates, and the top of the concrete box 4 is backfilled inside this.

[0008] As shown in Figure 10, the open shield machine 1 is assembled at a predetermined position within the starting shaft 8. After assembly, the propulsion jack 3 of the open shield machine 1 is extended to use the reaction force from the reaction wall 9 within the starting shaft to move the open shield machine 1 forward, and the first concrete box 4 that forms the underground structure is lowered from above and set behind the retracted propulsion jack 3 within the tail section 19 of the open shield machine 1.

[0009] The concrete boxes 4 that are laid sequentially inside the departure shaft 8 are boxes that are temporarily laid as reaction force transmission materials after the open shield machine 1 propels forward and exits the departure shaft 8, and are then propelled a predetermined distance until the propulsion force of the open shield machine is no longer transmitted to the reaction force wall 9 inside the departure shaft 8, at which point the boxes are removed.

[0010] The departure shaft 8 is retained by a retaining wall 27, and a portion of this wall in front is cut away in order to launch the open shield machine 1. If necessary, ground improvement work 11 may be carried out in front of the departure shaft 8 by means of chemical injection or the like.

[0011] Next, after cutting off a portion of the retaining wall in front of the departure shaft 8, an excavator 6 such as a shovel is used to excavate and remove earth and sand from above the ground in front of the open shield machine 1.

[0012] Simultaneously with or after this soil-discharging process, the propulsion jack 3 is extended, and the open shield machine 1 is advanced while receiving a propulsion reaction force from the concrete box in the tail section 19 and the concrete box connected to the rear of it. During this advancement process, a press bar (push angle) 23 consisting of a frame made of box steel or mold steel is placed in front of the concrete box 4.

[0013] Then, after the open shield machine 1 moves forward the length of one box, the second concrete box 4 is lifted and lowered into the tail section 19 of the open shield machine 1 by the crane 24 and set in front of the first concrete box 4.

[0014] Thereafter, the same excavation and soil removal process, advancement process, and concrete box 4 setting process are repeated as appropriate, and the concrete boxes 4 are successively left in the ground in a vertical row as the open shield machine 1 advances. As shown in Figure 13, the top surfaces of these concrete boxes 4 are backfilled and the surface is paved.

[0015] In the process of setting the concrete box 4, although not shown in the figure, after the concrete box 4 is set inside the tail machine, backfill injection material is injected as a primary injection, and then backfill injection material is injected as a secondary injection into voids that occur in the ground during the excavation, soil removal, and forward movement processes of the open shield machine 1.

[0016] Once the open shield machine 1 reaches the destination tunnel 13, it is removed and the construction is completed.

[0017] The concrete box 4 is made of reinforced concrete and is a single rectangular piece consisting of a left slab, a right slab, a top slab, and a bottom slab, with openings on the front and back. Grout holes are provided near the center of each of the left and right side slabs and the bottom slab, and as mentioned above, backfill injection material is injected and filled from these grout holes as primary injection and secondary injection into tail voids that occur in the ground after the concrete box 4 is installed in the tail section 19 and as the open shield machine 1 excavates.

[0018] The concrete box 4 is connected to the connecting end faces of the concrete by installing flexible members with a specified earthquake resistance performance between them, and when the open shield machine 1 excavates such a flexible concrete box 4, the shield jack 3 is extended and the open shield machine 1 moves forward while receiving a thrust reaction force from the concrete box 4 in the tail section 19 and the subsequent concrete box 4 connected to it, so it is necessary to fix the connecting end faces of the flexible concrete box 4 so that no misalignment occurs between them.

[0019] Furthermore, as the open shield machine 1 advances, it is affected by the resistance of the ground at the tunnel face in front of the shield machine 1 and the frictional resistance of the ground in contact with both side plates 1a and bottom plate 1b of the shield machine 1, and as it advances, the shield machine 1 sways slightly up and down and left and right. At this time, the shield machine 1 may snake a lot in the up and down and left and right cross-sectional directions depending on the type of soil in the cross-sectional direction of the ground at the tunnel face, the deposition situation and partial hardness / softness, and the complex soil deposition situation in the ground in the direction of advancement.

[0020] It is necessary to control the meandering of the shield machine while advancing it, and to do this, multiple advancing jacks 3 are placed symmetrically with respect to the cross section of the shield machine, but this causes an unbalanced load to act on the concrete box that has already been laid behind it, which generates a shear force that tends to cause a misalignment between the connecting end faces of the laid box.

[0021] Based on the above, in order to prevent misalignment between the connecting end faces of the flexible concrete boxes 4 when the shield machine is advanced, it is common to install anti-slip steel materials 28 as shown in Figures 14 to 17, which are used to restrain the concrete boxes 4 from each other.

[0022] Such anti-slip steel material 28 is made of shaped steel and is fastened to the concrete box body 4 by bolts 30 in bolt holes 29 formed in the concrete box body 4 .

[0023] The following Patent Document 1 shows that when a flexible box culvert is pushed underground from a starting shaft using the jacking method, an X-shaped anti-snake fitting is installed between the connecting end faces on the inner surface of the concrete box to prevent the box culvert from twisting or shifting due to jacking.

[0024] Furthermore, Patent Document 2 below discloses that when constructing a circular tunnel using the shield tunneling method, the segments are connected in the circumferential direction between each piece with a curved bolt.

[0025] These curved bolts are fastened at both ends with nuts or other fasteners to prevent gaps at the connecting end faces between the piece segments or misalignments (steps) between the segments in the tunnel extension direction due to the shield machine's excavation thrust. In other words, the fastening of the curved bolts maintains the circular shape of the segments in the circumferential direction during excavation after the individual divided segments are assembled. The curved bolts are then removed when the excavation thrust acting on the segments is no longer in its range of effect. [Patent Document 1] Patent No. 2937836 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-118306 Summary of the Invention [Problem to be solved by the invention]

[0026] The slippage prevention steel material 28 shown in Figs. 14 to 17 and the invention of the meandering prevention metal fittings of Patent Document 1 use large steel materials, and therefore are heavy.

[0027] Furthermore, when transporting the anti-slip steel from inside the installed flexible concrete box behind the open shield machine to the installation location, the longer the installation distance of the installed flexible concrete box, the longer the transportation time will be, and the heavier the transport weight will be, so transportation equipment will also be required.

[0028] Furthermore, when anti-slip steel is dropped from above the tail of the open shield machine, the anti-slip steel is large and heavy, so it must be dropped from above using a lifting machine or similar equipment, requiring careful consideration of safety.

[0029] In addition, when installing the above-mentioned anti-slip steel material or the anti-snakeway fittings described in Patent Document 1 in a flexible concrete box, the smaller the internal space of the flexible concrete box becomes, the smaller the working space available to workers for installation work, making the installation work extremely difficult.

[0030] Furthermore, the larger the flexible concrete box and the larger its internal cross section, and the heavier the flexible concrete box, the more difficult it becomes for workers to install it on the top plate and upper part of the side wall inside the flexible concrete box.

[0031] Furthermore, the anti-slip steel and anti-snakeway fittings are fixed to the inner surface of the flexible concrete box with hole-in anchors or other bolts that are inserted into pre-installed bolts, but the installation work takes time because there are a large number of bolts to be installed.

[0032] Furthermore, the more bolts are installed, the more precision is required in the orientation of hole-in anchors, the spacing between them, etc. If the installation precision is poor, the bolts cannot be inserted accurately into the hole-in anchors, etc., and there will be places where the bolts do not function properly.

[0033] Therefore, if the amount of meandering control during construction using the open shield machine or the jacking method in Patent Document 1 is increased, depending on the usage conditions of the jacking, an unbalanced load will act on the flexible concrete box, and the shear force that tends to cause misalignment between the connecting end faces of the flexible concrete box will increase, causing excessive shear force to act on some of the bolt installation locations, which may result in defects such as cracks in the concrete near those locations.

[0034] As mentioned above, in Patent Document 2, in order to construct a tunnel using the shield tunneling method, when each divided piece segment is assembled into a circular shape, the connecting end faces between the pieces of the piece segments are fastened with curved bolts, and the curved bolts are removed when the effects of openings etc. caused by the thrust force acting on the segments when the shield machine excavates disappear during use, but it does not show how to remove them.

[0035] The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional examples and to provide a method for preventing and releasing the slippage of a concrete box for use in the open shield construction method using a lightweight anti-slip material that can be easily, simply, and safely installed and removed by workers. [Means for solving the problem]

[0036] In order to achieve the above object, the present invention as set forth in claim 1 provides a curved sheath hole that runs continuously from the haunch surface at each of the four corners of the concrete boxes to be connected to the connecting end surface, and a curved pin with both ends protruding from each of the haunch surfaces is inserted from one of the sheath hole openings to prevent slippage at the connecting end surface between the concrete boxes, and when there is no longer a need to prevent slippage, the curved pin can be removed by pushing or pulling it out.

[0037] According to the present invention as set forth in claim 1, by installing curved pins at the four corners between the connection end faces of the connected boxes, the connection end faces are fixed in place to prevent misalignment in the cross-sectional direction. Therefore, even if a thrust reaction force acts asymmetrically on the flexible concrete box immediately behind the thrust jack due to meandering correction during excavation by the open shield machine, the pins will not slip out of or come out of the sheath hole, and no misalignment of the concrete boxes will occur between the connection end faces.

[0038] Furthermore, the ends of the curved pins protruding from the haunch surfaces are not fastened or fixed with nuts or the like, and therefore the problem of "stress at the joint concentrating on the bolt insertion hole and causing early cracks in the concrete of the insertion hole wall" that occurs when a curved bolt is fastened with a nut as described in the reference document of Patent Document 2 above does not occur.

[0039] Furthermore, the curved pins used to prevent slippage are much lighter than steel, and the steel slippage prevention material does not need to be fastened or fixed between the connecting end faces with numerous bolts and nuts and hole-in anchors pre-installed in the concrete box, making the work easier and simpler for workers to carry out.

[0040] Furthermore, since the slippage prevention structure is provided only at the haunch portions at the four corners of the concrete box, the sheath holes can be installed with high precision.

[0041] The curved pin can be removed by pushing or pulling it out, so that it can be easily and reliably removed when there is no longer any need to prevent slippage.

[0042] The present invention as set forth in claim 2 is characterized in that the curved pin is a semicircular curved pin, and the method of pushing out and removing the curved pin is to insert a pin having the same radius of curvature as the axis of the pin through one of the sheath holes, and then push out and remove the curved pin.

[0043] According to the present invention as set forth in claim 2, the semicircular curved pin can be easily removed by placing a pin having the same curved shape as the semicircular curved pin on one end of the pin and hitting the pin with a hammer or the like to push it out of the sheath hole.

[0044] The present invention as described in claim 3 is characterized in that the curved sheath holes are connected to the short straight sheath holes in the haunch portions at each of the four corners of the inner surface of the other concrete box to be connected, the curved pins are bolts with short straight end portions, and the curved pins are pulled out and removed by inserting a wedge plate that holds the bolt between the bolt head and the surface of the haunch at the bolt insertion position.

[0045] According to the present invention as set forth in claim 3, a bolt having a short, straight end is inserted and installed between the connecting end faces of the haunch portions at the four corners of the inner surface of the flexible concrete box to be connected, so that the curved pin can be easily inserted into the sheath hole.

[0046] Furthermore, when removing the bolt, a wedge plate can be inserted between the bolt and the concrete surface where the bolt protrudes, making removal easy. [Effects of the Invention]

[0047] As described above, the method of fixing and releasing the slippage prevention of a concrete box for the open shield construction method of the present invention uses a lightweight slippage prevention material that can be easily, simply, and safely installed and removed by workers. [Brief explanation of the drawings]

[0048] [Figure 1] 1 is a perspective view showing a first embodiment of a method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same according to the present invention. [Figure 2] 1 is a perspective view of a main part showing a first embodiment of a method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same according to the present invention. [Figure 3] 1 is a vertical cross-sectional side view showing a first embodiment of a method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same according to the present invention. [Figure 4] FIG. 1 is a perspective view showing the removal of a pin in a first embodiment of the method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same in accordance with the present invention. [Figure 5] FIG. 10 is a perspective view showing a second embodiment of the method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same according to the present invention. [Figure 6] FIG. 10 is a vertical cross-sectional side view showing a second embodiment of the method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same according to the present invention. [Figure 7] FIG. 10 is a perspective view of the main part showing a second embodiment of the method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same according to the present invention. [Figure 8] FIG. 10 is a perspective view showing the removal of a pin in a second embodiment of the method for preventing slippage of a concrete box for an open shield tunneling method and for releasing the same in accordance with the present invention. [Figure 9] FIG. 1 is a perspective view showing the construction status of the open shield method. [Figure 10] FIG. 2 is a side view showing the first step of the open shield construction method. [Figure 11] FIG. 10 is a side view showing the second step of the open shield construction method. [Figure 12] FIG. 10 is a side view showing the third step of the open shield construction method. [Figure 13] FIG. 10 is a side view showing the fourth step of the open shield construction method. [Figure 14] FIG. 10 is a cross-sectional plan view showing a conventional example. [Figure 15] FIG. 10 is a vertical cross-sectional side view showing a conventional example. [Figure 16] FIG. 10 is a vertical sectional front view showing a conventional example. [Figure 17] FIG. 10 is a vertical sectional front view of a main part showing a conventional example. DETAILED DESCRIPTION OF THE INVENTION

[0049] The following describes in detail the embodiments of the present invention with reference to the drawings. Figure 1 is a perspective view showing a first embodiment of the method for fixing and releasing a concrete box for the open shield tunneling method of the present invention, Figure 2 is a perspective view of the main part of the same, and Figure 3 is a longitudinal side view of the same. The outline of the open shield tunneling method is the same as that explained above, so it will be omitted here.

[0050] In the figure, 43 is the haunch surface of the haunch portion on the inner surface of the concrete box 4, and curved sheath holes 33 are provided continuously from the haunch surface 43 at each of the four corners of the connecting concrete boxes 4 to the connecting end surface. The sheath holes 33 are in the shape of a quarter circle curve.

[0051] The sheath hole into which the semicircular curved pin 32 described below is inserted is provided as a quarter-circular curved sheath hole 33 from a position close to the connecting end face on the inner surface of one of the housings to the surface of the connecting end face.

[0052] In addition, a similar sheath hole 33 is installed in the other concrete box, and in the connected concrete box 4, both sheath holes 33 are continuous as a semicircular curved sheath hole between the connecting end faces.

[0053] The curved pin to be inserted into the sheath hole 33 from its opening is a semicircular curved pin 32, and the end of the semicircular curved pin 32 inserted from one opening of the sheath hole 33 projects from each haunch surface 43.

[0054] The semicircular curved pins 32 are fully inserted into the interior of both of the connected concrete boxes 4 from the haunch surfaces 43 at the four corners that are close to the connecting end faces on the inside of the connected flexible concrete boxes 4. Therefore, by fixing the four corners, the connecting end faces are fixed together, so there is no misalignment between the connecting end faces in the left-right or up-down direction.

[0055] The semicircular curved pin 32 can be easily inserted by hand by an operator into the sheath hole having the semicircular curved shape.

[0056] To remove the semicircular curved pin 32, a curved extrusion pin 34 is placed against one end of the semicircular curved pin 32 and a hammer is used to push out the semicircular curved pin 32 through the curved extrusion pin 34.

[0057] As a second embodiment of the present invention, as shown in Figures 5 to 7, a sheath hole 37 having a quarter-circular curve shape is installed from the haunch surface 43 located close to the connection end face on the inner surface of one of the concrete boxes 4 to the surface of the connection end face.

[0058] In addition, the other concrete box 4 has a short, straight sheath hole 38 installed from its connecting end face to the inside, and the sheath hole 37 and the sheath hole 38 are continuous between the connecting end faces of the connected flexible concrete boxes 4.

[0059] The curved pin to be inserted into the sheath hole is a one-sided semicircular curved bolt 36 formed of a quarter-circular curved portion and one side of which is a short straight portion that is shorter than the quarter-circular curved portion, and the head of the quarter-circular curved portion is threaded and a nut 39 is inserted into it.

[0060] The one-sided semicircular curved bolt 36 is installed between the haunch surfaces 43 at the four corners that are close to the connecting end faces on the inner surfaces of the connected concrete boxes 4, and is fully embedded inside both of the concrete boxes 4 through the connecting end faces.

[0061] The one-sided semicircular curved bolt 36 is a short, straight bolt continuing from the end of the quarter-circular curved portion, and is inserted into a continuous sheath hole consisting of the continuous sheath hole 37 and the sheath hole 38. In this case, the concrete boxes 4 to be connected may be opened slightly, and the short, straight portion of the one-sided semicircular curved bolt 36 may be inserted first, and then the concrete boxes 4 may be aligned. In this way, the one-sided semicircular curved bolt 36 can be easily inserted by hand by an operator.

[0062] Therefore, by installing the bolts 36 at the four corners, the connecting end faces are fixed to each other, so that no misalignment occurs between the connecting end faces in the left-right or up-down direction.

[0063] To remove the one-sided semicircular curved bolt 36, a nut 39 is placed on the threaded portion, and a wedge plate 40 is inserted between the nut and the haunch surface at the insertion position of the bolt 36 to clamp the one-sided semicircular curved bolt 36.

[0064] The wedge plate 40 has a slit notch 40a formed in the center into which the one-sided semicircular curved bolt 36 fits, and by pushing it in with a hammer or the like while gradually loosening the nut 39 and shifting its position, the one-sided semicircular curved bolt 36 is pulled out.

[0065] Furthermore, the one-sided semicircular curved bolt 36 is formed with a short straight section that is shorter than the quarter-circular curved section, and when this short straight section is removed from the short straight sheath hole 38 of the other concrete box 4, the anti-slip fixation between the concrete boxes 4 is released. [Explanation of symbols]

[0066] 1...Open shield machine 1a...Side wall plate 1b...Bottom plate 2...Cutting edge 3...Propulsion jack (shield jack) 4...Concrete box 5...Backfill 6...Excavator 7...Dump truck for removing soil 8...Departure shaft 9...Reaction wall 10...Backfilling heavy equipment 11...Ground improvement 13…reaching hole 14…PC steel rod 15...Dump truck for backfilling 16a...Sliding retaining plate 17...Front machine 18...Tail machine 19...Tail section 21...Backfill injection plant 23...Press bar (push angle) 24...Lifting machine 25...Backfill injection material 27...Earth retaining wall 28...Slip-prevention steel 29...Bolt hole 30...Bolt 31...Hole-in anchor 32...Semicircular curved pin 33...Sheath hole 34...Curved ejector pin 35...Hammer 36...One-sided semicircular curved bolt 37...Sheath hole 38...Sheath hole 39...Nut 40...Wedge plate 40a...Slit notch 43...Haunch surface 51...Bent part

Claims

1. A method for preventing and releasing slippage of concrete boxes for use in open shield construction, characterized in that curved sheath holes are installed continuously from the haunch surfaces at each of the four corners of the concrete boxes to be connected to the connecting end surfaces, and a curved pin with both ends protruding from each of the haunch surfaces is inserted through one of the sheath hole openings to prevent slippage at the connecting end surfaces between the concrete boxes, and when slippage prevention is no longer necessary, the curved pin is removed by pushing or pulling out.

2. 2. A method for preventing slippage of a concrete box for an open shield construction method as described in claim 1, wherein the curved pin is a semicircular curved pin, and the method for pushing out and removing the curved pin comprises inserting a pin having the same radius of curvature as the axis of the pin through a sheath hole on one side, and pushing out and removing the curved pin.

3. 2. A method for preventing slippage of a concrete box for an open shield construction method, as set forth in claim 1, wherein the curved sheath holes are connected to short, straight sheath holes in the haunch portions at each of the four corners of the inner surface of the other concrete box to be connected, the curved pins are bolts with short, straight ends, and the curved pins are pulled out and removed by inserting a wedge plate that holds the bolt between the bolt head and the surface of the haunch at the bolt insertion position.

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