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: A blockout 42 is installed in proximity to a connection end face side of a haunch part 43 on four corners on inner face of one concrete box body 4 to be connected. A sheath hole 44 is formed so as to continue from the blockout and extend to the connection end face of the concrete box body 4. A sheath hole 44' is formed from the connection end face to the inside of the haunch part 43 on four corners of the inner face of the other concrete box 4 to be connected. The sheath holes 44, 44' continue between the connection end faces when the concrete box bodies 4 are connected. A threaded part 45 at an end of a bolt 41 protrudes from the inner face on the connection end face side of the blockout 42. Displacement between the connection end faces is prevented by inserting the bolt as a displacement prevention pin from the blockout 42 into the sheath hole 44' of the other concrete box body 4. A nut 39 is installed on the threaded part 45 at the end of the bolt 41. The bolt 41 is pulled out and removed by turning the nut 39.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 an overview is shown in Figures 13 to 17.

[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] 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 bending section 53 at the mutual fitting portion, making it bendable. A bending jack is provided at this bending section 53.

[0006] The front machine 17 mainly serves as the excavation section, and the tail machine 18 has the propulsion jack 3 arranged therein, and serves as the tail section 19 which serves as the section for hoisting and setting down the concrete box body 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. 54 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 14, 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, as shown in Figure 20.

[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] 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 a crane 24 and set in front of the first concrete box 4, as shown in Figure 20.

[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 16, 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] As a result of the above, as shown in Figure 17, once the open shield machine 1 reaches the arrival tunnel 13, it is removed and the construction is completed.

[0017] Although not shown, the concrete box 4 is made of reinforced concrete and is a rectangular, one-piece structure consisting of a left-side slab, a right-side slab, a top slab, and a bottom slab, with openings at 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 through 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] If a flexible component with a specified earthquake resistance is installed between the connecting end faces of the flexible concrete box 4, it is necessary to fix it so that no misalignment occurs between the connecting end faces of the flexible concrete box 4 when the open shield machine 1 is advanced.

[0019] Furthermore, when the open shield machine 1 is advanced, it is affected by frictional resistance with the ground, and it is necessary to advance the open shield machine 1 while controlling its meandering.

[0020] To achieve this, it is necessary to control the meandering by using multiple propulsion jacks 3 arranged symmetrically with respect to the cross section of the open shield machine in an asymmetrical manner, but this causes an unbalanced load to act on the already laid box body at the rear, which generates a shear force that tends to cause a misalignment between the connecting end faces of the laid box body.

[0021] Conventionally, in order to prevent misalignment between the connecting end faces of the flexible concrete box, anti-slip steel members 28 have been installed as shown in Figs. 18 to 21.

[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. [Patent Document 1] Patent No. 2937836 Summary of the Invention [Problem to be solved by the invention]

[0024] The method of installing anti-slip steel members for flexible boxes using the open shield construction method described above and the invention of the anti-snakeway fittings in Patent Document 1 use large steel members, which makes them heavy.

[0025] 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.

[0026] 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.

[0027] In addition, when installing the above-mentioned anti-slip steel material or the anti-snake 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.

[0028] Furthermore, the larger the flexible concrete box is, the larger the internal cross section is, and the heavier the flexible concrete box is, the more difficult it becomes for workers to install it on the top plate or upper part of the side wall inside the flexible concrete box.

[0029] The anti-slip steel and anti-snakeway fittings are fixed to the inside 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 as there are a large number of bolts to be installed.

[0030] Furthermore, the more anchors that are installed, the more precision is required in the orientation of the hole-in anchors, the spacing between them, etc. If the installation precision is poor, the bolts will not be able to be inserted accurately into the hole-in anchors, etc., and there will be places where the bolts will not function properly.

[0031] 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, resulting in excessive shear force acting on some of the bolt installation locations, which may cause defects such as cracks in the concrete near those locations.

[0032] 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, which uses lightweight slippage prevention materials and can be easily, simply, and safely installed and removed by workers. [Means for solving the problem]

[0033] In order to achieve the above object, the present invention as described in claim 1 is characterized in that a box cutout is installed close to the connecting end face of the haunch portion at each of the four corners of the inner surface of one of the concrete boxes to be connected, sheath holes are formed so as to extend from this box cutout to the connecting end face of the concrete box, sheath holes are formed from the connecting end face of the haunch portion at each of the four corners of the inner surface of the other concrete box to be connected to the inside, both sheath holes are continuous between the connecting end faces when the concrete boxes are connected, a bolt with a threaded portion at the end protruding from the inner surface on the connecting end face side of the box cutout is inserted through the box cutout as an anti-slip pin and inserted into the sheath hole of the other concrete box to prevent slippage between the connecting end faces, a nut is installed on the threaded portion of the bolt end, and the bolt can be pulled out and removed by turning this nut.

[0034] According to the present invention described in claim 1, between the connecting end faces at the haunch portions at the four corners of the inner surface of the flexible concrete boxes to be connected, the bolts are inserted from the box cutout installed on one of the flexible concrete boxes through the sheath hole connected to that box cutout to the sheath hole installed on the flexible concrete box of the other method, thereby preventing slippage in the cross-sectional direction, as if the inserted bolts were fixed in place at four points.

[0035] Furthermore, when removing the bolt, the portion of the bolt that protrudes toward the inner surface of the box cutout is threaded and a nut is installed in contact with the inner surface of the box cutout, so the bolt can be easily removed by turning the nut.

[0036] The gist of the present invention as set forth in claim 2 is that the sheath hole and the bolt have polygonal cross sections.

[0037] According to the present invention as set forth in claim 2, since both the sheath hole and the bolt have polygonal cross sections, even if a misalignment occurs between the connection end faces that causes twisting in the cross-sectional direction, the rectangular portions of the sheath hole and the bolt come into contact and resist the twisting.

[0038] Therefore, when the open shield machine is excavating, not only is there no misalignment between the connection end faces of the connected concrete boxes in the vertical and horizontal directions, but there is also no misalignment due to twisting.

[0039] Furthermore, by turning the nut when removing the bolt, the bolt can be easily removed without being rotated when the bolt is pulled out.

[0040] The present invention as described in claim 3 is characterized in that the bolt head is polygonal, a nut is screwed onto the threaded portion below it, and the bolt head is rotated to move the bolt relative to the nut and remove it.

[0041] According to the present invention described in claim 3, when removing the bolt, the portion of the bolt that protrudes toward the inner surface of the box cutout is threaded, a nut is installed in contact with the inner surface of the box cutout, and the head of the bolt is polygonal, so the bolt can be easily removed by pressing and fixing the nut and turning the head plate of the bolt.

[0042] The present invention described in claim 4 is characterized in that the bolt head is polygonal, the shank below it is threaded to a predetermined length, and a first connecting pin with a female thread threaded in the opposite direction to the threading on the head side is threaded into the other end of the shank, and a second connecting pin with a male thread on the female threaded part of the first connecting pin is threaded into it to form a linked bolt, and a nut is screwed between the bolt head and the connecting end face side of the box cutout, and the bolt head is rotated to move the bolt relative to the nut and remove it.

[0043] According to the present invention as set forth in claim 4, between the connecting end faces at the haunch portions at the four corners of the inner surface of the flexible concrete boxes to be connected, bolts are inserted from the box cutout installed on one of the flexible concrete boxes through the sheath hole connected to it to the sheath hole installed on the flexible concrete box of the other method to prevent misalignment, so that the connecting end faces resist misalignment in the cross-sectional direction as if they were surface-fixed at four points by the bolts inserted into the sheath holes.

[0044] Furthermore, when removing the connecting bolt, the shaft of the connecting bolt is fixed with the second connecting pin to prevent it from rotating, so the bolt head can be rotated to move the bolt relative to the nut and remove it. [Effects of the Invention]

[0045] 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]

[0046] [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 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 3] 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 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. 10 is a perspective view showing a third 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 10] FIG. 10 is a vertical cross-sectional side view showing a third 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 11] FIG. 10 is a perspective view of the main part showing a third 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 12] 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 13] FIG. 1 is a perspective view showing the construction status of the open shield method. [Figure 14] FIG. 2 is a side view showing the first step of the open shield construction method. [Figure 15] FIG. 10 is a side view showing the second step of the open shield construction method. [Figure 16] FIG. 10 is a side view showing the third step of the open shield construction method. [Figure 17] FIG. 10 is a side view showing the fourth step of the open shield construction method. [Figure 18] FIG. 10 is a cross-sectional plan view showing a conventional example. [Figure 19] FIG. 10 is a vertical cross-sectional side view showing a conventional example. [Figure 20] FIG. 10 is a vertical sectional front view showing a conventional example. [Figure 21] FIG. 10 is a vertical sectional front view of a main part showing a conventional example. DETAILED DESCRIPTION OF THE INVENTION

[0047] 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 longitudinal sectional side view of the same, and Figure 3 is a perspective view of the main part of the same. The outline of the open shield tunneling method is the same as that explained above, so it will be omitted here.

[0048] In the figure, reference numeral 43 denotes a haunch portion on the inner surface of the concrete box 4, and a box cutout 42 is formed adjacent to the connecting end face side of the haunch portion 43 on the inner surface of one of the connected concrete boxes 4.

[0049] A sheath hole 44 is formed so as to extend from this box cutout 42 to the connecting end surface of the concrete box body 4 .

[0050] Sheath holes 44' are formed from the connecting end faces of the haunch portions 43 at each of the four corners of the inner surface of the other concrete box 4 to be connected to the inside, and the two sheath holes 44, 44' are continuous between the connecting end faces when the concrete boxes 4 are connected to each other.

[0051] In the figure, reference numeral 41 denotes a bolt to be inserted into the sheath holes 44, 44', and one end is provided with a cylindrical thread as a threaded portion 45, onto which a nut 39 can be screwed.

[0052] The sheath holes 44, 44' and the threaded portion 45 of the bolt 41 have a polygonal cross section, and in the illustrated example, a rectangular cross section.

[0053] In this way, the threaded portion 45 protrudes into the box cutout 42 and the bolt 41 is installed, the nut 39 is inserted into the threaded portion 45, and the inner surface of the nut 39 abuts against the inner surface of the connection end face side of the box cutout 42.

[0054] A bolt 41 is inserted into the sheath hole 44 connected to the box cutout 42, and inserted into the rectangular sheath hole 44' into the concrete of the haunch portion 43 on the inner surface of the other flexible concrete box 4, and then installed.

[0055] By installing the bolts 41 at the four corners between the connecting end faces on the inside of the connected concrete boxes, the connecting end faces are fixed to each other, so no misalignment occurs between the connecting end faces in the left-right or up-down directions.

[0056] To remove the bolt 41, the inner surface of the nut 39 is installed in contact with the inner surface of the box cutout, so that the bolt 41 is pulled out toward the inside of the box cutout by turning the nut 39 in the tightening direction.

[0057] In this case, since the sheath holes 44, 44' and the threaded portion 45 of the bolt 41 have a polygonal, for example rectangular, cross section, it is possible to prevent the bolt 41 from rotating together with the rotation of the nut 39.

[0058] Also, once the tip of the bolt 41 is removed from the sheath hole 44', it is possible to remove the bolt 41 by hand without using the nut 39. On the other hand, it is desirable that the sheath hole 44' be short.

[0059] As shown in Figures 7 and 8, in a second embodiment of the present invention, a box cutout 42 is formed adjacent to the connecting end face of the haunch portion 43 on the inner surface of one of the connected concrete boxes 4, and sheath holes 47 are formed so as to extend from this box cutout 42 to the connecting end face of the concrete box 4. Sheath holes 47' are formed from the connecting end face of the haunch portion 43 at each of the four corners of the inner surface of the other connected concrete box 4 to the inside, and both sheath holes 47, 47' are continuous between the connecting end faces when the concrete boxes 4 are connected to each other, just like in the first embodiment.

[0060] The bolt 46 is a threaded bolt with a circular cross section, one end of which is threaded and a head plate 48 is attached to the head of the threaded portion, and is inserted up to the sheath hole 47' in the haunch portion 43 on the inner surface of the other concrete box 4.

[0061] The bolt 46 can be removed by turning the nut 39 in the tightening direction while fixing the head plate 48 of the bolt 46 so that it does not rotate, since the inner surface of the nut 39 is installed in contact with the inner surface of the box cutter 42. Then, the bolt 46 is pulled out toward the inside of the box cutter 42.

[0062] As a third embodiment of the present invention, as shown in Figures 11 and 12, a box cutout 42 is formed on the inner surface of one of the connected concrete boxes 4 adjacent to the connecting end face of the haunch portion 43, and sheath holes 47 are formed so as to extend from this box cutout 42 to the connecting end face of the concrete box 4. Sheath holes 47' are formed inward from the connecting end face of the haunch portion 43 at each of the four corners of the inner surface of the other connected concrete box 4, and both sheath holes 47, 47' are continuous between the connecting end faces when the concrete boxes 4 are connected to each other, which is the same as the second embodiment.

[0063] The bolt 52 is a connecting bolt having a polygonal head plate 48, a shaft 49 with a female screw thread running from the other end of the plate 48 to the inside, a first connecting pin 50 with a male screw thread at one end and a female screw thread running from the other end to the inside in the opposite direction to the thread on the head side, and a second connecting pin 51 with a male screw thread at one end.

[0064] A connecting bolt 52 with a circular cross section is inserted through the box cutout 42 and a sheath hole 47' in the haunch portion 43 on the inner surface of the other concrete box 4.

[0065] The connecting bolt 52 is connected by sequentially inserting the second connecting pin 51, the first connecting pin 50, and the shaft 49 into the box cutout 42, so that the length of the box cutout is shorter than that of a conventional concrete box. Therefore, the post-processing of filling the box cutout 42 with mortar or the like can be reduced.

[0066] The bolts 52 are installed between the haunch portions 43 at the four corners that are close to the connecting end faces on the inner surface of the connected flexible concrete boxes, and are fully embedded inside both boxes through the connecting end faces.By installing the bolts 52 at the four corners, the connecting end faces are fixed in place, so no misalignment occurs between the connecting end faces in the left-right or up-down directions.

[0067] The connecting bolt 52 is removed by turning the nut 39 in the tightening direction while fixing the head plate 48 of the shaft 49 so that the head plate 48 of the shaft 49 does not rotate. This causes the bolt 52 to be pulled out toward the inside of the box cutout, allowing the bolt 52 to be removed by sequentially removing the shaft 49 and the two connecting pins. This allows the bolt 52 to be easily removed. [Explanation of symbols]

[0068] 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 39 Nut 41...Rectangular bolt 42...Box cutout 43...Haunch 44, 44'...Rectangular sheath hole 45...Rectangular bolt threaded section 46...Threaded bolt 47, 47'...Sheath hole 48...Head plate 49...Shaft 50...First connecting pin 51...Second connecting pin 52...Connecting bolt 53...Bent part 54...Rear retaining wall

Claims

1. a bolt with a threaded end protruding from the inner surface of the connecting end face of the box cutout as an anti-slip pin, which is inserted through the box cutout into the sheath hole of the other concrete box to prevent slippage between the connecting end faces; a nut is attached to the threaded end of the bolt, and the bolt is turned to pull out and remove the bolt.

2. 2. A method for preventing and releasing displacement of a concrete box for use in an open shield construction method according to claim 1, wherein the sheath holes and the bolts have polygonal cross sections.

3. A method for preventing and releasing slippage of a concrete box for an open shield construction method as described in claim 1, in which the bolt head is polygonal, a nut is screwed onto the threaded portion below it, and the bolt head is rotated to move the bolt relative to the nut and remove it.

4. 2. A method for preventing and releasing slippage of a concrete box for an open shield construction method as described in claim 1, wherein the bolt head is polygonal, the lower shank is threaded to a predetermined length, and the other end of the shank is threaded with a first connecting pin having a female thread threaded in the opposite direction to the threading on the head side, and a second connecting pin having a male thread on the female threaded portion of the first connecting pin, to form a connected bolt, and a nut is screwed between the bolt head and the connection end face of the box cutout, and the bolt head is rotated to move the bolt relative to the nut and remove it.

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