JP2008115576A - Method for binding concrete caisson for open-shield method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for binding concrete caissons for an open-shield method, which can reduce the number of the caissons to be removed, which can simplify a structure, which imparts a specified tension so that a column of the concrete caissons can be fixed, and which enables the concrete caisson to be surely anchored in a prescribed position. <P>SOLUTION: In this method for binding the concrete caissons 4 for use in the open-shield method, a binding bolt 14 is screwed into an insert 12 which is pre-embedded in the joint end of the concrete caisson 4; a leading end of the bolt 14 is protruded forward from the joint end; a protruding end of the bolt 14 is inserted into the next concrete caisson 4 which is laid ahead of the above concrete caisson 4; a nut 16 is attached to the protruding end of the bolt 14 so as to be temporarily fastened; a shield machine is propelled by the reaction from the concrete caisson 4; in the state of the action of an axial compressive force on the rear concrete caisson 4, the nut 16 pre-attached to the leading end of the bolt 14 is finally fastened so that the concrete caissons 4 in front and rear positions can be bound together. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for binding a concrete box in an open shield method in which an underground structure such as an attached underground passage such as a water and sewage system, a common ditch, a telegraph and a telephone is constructed in an urban area or the like.

  The open shield method is a rational method that utilizes the advantages of the open cut method (open cut method) and the shield method, and the outline of the open shield machine 1 used in this open shield method is as shown in FIG. The front, rear, and top surfaces of the plate 1a and the bottom plate 1b connected to the side wall plates 1a are opened, the front ends of the side wall plate 1a and the bottom plate 1b are formed as blade edges 11, and the center of the side wall plate 1a is formed. Alternatively, the shield jacks 2 are arranged side by side in the vertical direction near the rear end. In the figure, 3 indicates a partition wall.

  The open shield method to be constructed using the open shield machine 1 is not shown in the figure, but the open shield machine 1 is installed in the start pit, the shield jack 2 of the open shield machine 1 is extended, and the inside of the start mine is The open shield machine 1 is advanced by taking the reaction force against the reaction wall, the first concrete box 4 forming the underground structure is suspended from above, and the shield is shrunk in the tail part 1c of the open shield machine 1 Set behind jack 2. A strut is disposed between the shield jack 2 and the reaction wall to adjust the distance appropriately.

  In addition, the start pit is made up of a retaining wall, and in order to start the open shield machine 1, a part of this retaining wall is mirror-cut. If necessary, the ground is improved at the front part of the starting pit by chemical injection or the like. Sometimes it is left.

  Excavator 9 such as an excavator excavates and removes soil from the front or top surface of open shield machine 1. Simultaneously with or after this earth removal step, the shield jack 2 is extended to advance the open shield machine 1. In the case of this forward process, a press bar 8 made of a frame body made of box steel or mold steel is disposed in front of the concrete box 4, and the open shield machine 1 reacts from the concrete box 4 set rearward. Take.

  Then, the second concrete box 4 is suspended in the tail part 1 c of the open shield machine 1 in front of the first concrete box 4. Thereafter, the same earth removal process, forward process, and concrete box 4 setting process are repeated as appropriate, and the concrete boxes 4 are sequentially left in the ground as the open shield machine 1 moves forward. Put backfill 5 on the upper surface of the body 4.

  When the concrete box 4 is suspended in the tail part 1c of the open shield machine 1, a height adjusting material 7 such as a concrete block is disposed under the concrete box 4, and the concrete part 4 is placed in the tail part 1c. The grout material 6 is filled in the left and right and lower spaces of the box 4.

  In this way, if the open shield machine 1 reaches the reaching mine, it is removed and the construction is completed.

  In such an open shield construction method, as described above, the concrete box 4 is left in the ground in a column as the open shield machine 1 advances, and the concrete box 4 is suspended in the tail portion 1c of the open shield machine 1. As the open shield machine 1 moves forward, it leaves the tail portion 1c and remains in the ground. The open shield machine 1 takes a reaction force on the concrete box 4 left in the ground in this way. Advance.

  The concrete box 4 is made of reinforced concrete and comprises a left side plate 4a, a right side plate 4b, an upper floor plate 4c, and a lower floor plate 4d as shown in FIG.

  By the way, in order to embed the concrete boxes 4 buried in a column in the ground in a predetermined position, it is necessary to finally connect those located at the front and rear at the time of joining.

  As a method for this purpose, as shown in FIGS. 8 and 9, a through hole is provided in the front and rear direction in a haunch portion which is a corner portion of the concrete box 4, and a sheath tube is inserted therein to form a sheath hole 31. By inserting a fastening member such as a PC steel rod 32 into the interior, the concrete boxes 4 arranged in the front and rear columns are rigidly connected by fastening them.

  Tightening with the PC steel bar is performed by removing the box (not shown) at appropriate intervals in the concrete box 4 and connecting the PC steel bar at the box opening.

  Tightening the PC steel bar is done by tensioning the PC steel bar with a tension jack set on the front surface of the frontmost concrete box 4, but all the jacks set at the four corners of the concrete box 4 are simultaneously Rather than actuate, he was set on a diagonal and actuated one by one, and was nervous.

  The prior art is generally performed by those skilled in the art, and is not related to a known invention.

  In the above-described tightening method, a large number of boxes are required, and the PC steel bar requires a long length because the entire length of the column concrete box is penetrated and fastened with the PC steel bar. It is conceivable that sufficient tightening force cannot be obtained because it is only fastened with a PC steel rod.

  The object of the present invention is to eliminate the inconveniences of the conventional example, reduce the number of boxes, simplify the structure, fix a column of concrete boxes by applying a specified tension, and fix the concrete box in place. An object of the present invention is to provide a method for binding a concrete box in an open shield method that can firmly fix the body.

  In order to achieve the above object, the invention according to claim 1 includes a step of excavating and discharging soil in front of an open shield machine or a front opening of the open shield machine, and extending a propulsion jack to depress the concrete box. The process of advancing the shield machine with force and the process of hanging and setting a new concrete box from the upper side behind the propulsion jack shrunk in the tail part of the shield machine are repeated as appropriate to sequentially put the concrete boxes in tandem. This is a method for binding a concrete box in the open shield method to be embedded. Screw a bolt for fastening into an insert that has been embedded in advance in the joint end of the concrete box, and move the bolt tip forward from the joint end. Insert the protruding end of the bolt into the next concrete box laid in front of the concrete box and remove the nut here. Attach and temporarily tighten, and then push the shield machine against the concrete box and push the nut that was attached to the end of the bolt while the axial compression force is acting on the concrete box behind. Then, the gist is to bind the concrete box at the front and rear positions.

  According to the first aspect of the present invention, the bolt is tightened in a state in which a reaction force is applied to the concrete box by propulsion of the open shield machine, so that the bolt is tightened with a predetermined tension. Because it can be fastened, the front and back concrete boxes can be securely tightened with the prescribed tension.

  Furthermore, since the concrete box is fastened with only bolts in the vicinity of the joint end face as described above, it is effective for curved construction, and one box is enough for one bolt, The number can be reduced, and the structure becomes simple.

  The gist of the invention described in claim 2 is that a loosening prevention means is provided on the fastening bolt.

  According to the second aspect of the present invention, by providing the loosening prevention means, the fixing is stabilized even if only the bolts are tightened, and the concrete box can be securely fixed at a predetermined position.

  The invention described in claim 3 is characterized in that the loosening prevention means is a Nord lock washer, and the invention described in claim 4 is that the loosening prevention means is a pair of wedge washers.

  According to the third and fourth aspects of the present invention, by using a Nord lock washer or a wedge washer as a loosening prevention means, it is possible to reliably prevent loosening with a simple structure in which a simple hardware is attached to the bolt. The concrete box can be securely fixed in place.

  As described above, the method of binding the concrete box in the open shield method of the present invention is to tighten the bolts for tightening when the concrete boxes embedded in the front and rear columns are tensioned and fixed by the open shield method. The number of unboxing can be reduced, the structure can be simplified, and the concrete boxes in a column can be fixed in a state where a prescribed tension is applied, so that the concrete boxes can be firmly fixed at predetermined positions.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal side view showing an embodiment of a method for binding a concrete box in the open shield method of the present invention, and the open shield method in which the method for binding a concrete box of the present invention is implemented is the same as the conventional example. Therefore, detailed description here is omitted.

  The present invention is a binding method for fixing a plurality of concrete boxes 4 embedded in a column to each other and finally fixing them in a predetermined position. The concrete box 4 has a front surface as shown in FIGS. An insert 12 for screwing a tightening bolt is embedded in advance, and a box opening 15 for fixing the tightening bolt is formed on the rear surface.

  In this case, both the insert 12 and the box remover 15 are embedded in the haunch portion, which is a thick portion at the four corners of the concrete box 4, but in the concrete box 4 at the front and rear positions, Positioning is performed so that the box 15 is formed in the front concrete box 4 at a corresponding position on the extension line of the embedded insert 12.

  In the figure, reference numeral 13 denotes a breath bar disposed at the front end of the front concrete box 4.

  A method for connecting the concrete box 4 in which the insert 12 is buried and the box 15 is formed will be described with reference to FIGS. After laying the concrete box 4 at the rear, the base of the fastening bolt 14 is screwed into the insert 12 opened at the joint end, and the tip is projected from the joint end.

  When the next concrete box 4 is laid in front of the rear concrete box 4, the protruding end of the fastening bolt 14 protruding from the rear concrete box 4 is used for bolting the front concrete box 4. The nut 16, the Nord lock washer 17, and the washer 18 are attached to the tip as a fixing tool, the fixing plate 19 is installed at the rear of the box opening 15, and the nut 16 is tightened and temporarily tightened. The front concrete box 4 is temporarily fixed to the rear concrete box 4.

  The Nord lock washer 17 functions as a means for preventing the bolt 14 from loosening.

  After the temporary fastening, the open shield machine 1 is further propelled by applying a reaction force to the concrete box 4. In this state, a reaction force acts on the concrete box 4 and an axial compression force is acting. Therefore, a constant tension can be expected by further tightening the bolts 14 and further tightening them during the propulsion of the open shield machine 1.

  Then, the bolts 14 are tightened so that the Nord lock washer 17 is also tightened, and even if the nut 16 tries to rotate in the loosening direction, the taper portion formed on the Nord lock washer 17 prevents the nut 16 from loosening.

  As a result, the bolts 14 are securely fixed, and the front and rear concrete boxes 4 are securely fixed at predetermined positions.

  The means for preventing loosening of the bolt 14 is not limited to the Nord lock washer 17 but may be a wedge-shaped washer 20 shown in FIGS. 3, 4, and 5. The wedge-shaped washer 20 is composed of a pair of wedge bodies 20a and 20b. One wedge body 20a has a long hole 21 through which a bolt 14 passes, and the other wedge body 20b has a diameter substantially equal to the diameter of the bolt 14. A round hole 22 having a diameter is formed, and grooves 23 are formed on opposite surfaces of the wedge bodies 20a and 20b.

  The wedge-shaped washer 20 can be driven after the bolt 14 is tightened to increase the tension of the bolt 14, and the loosening of the bolt 14 is prevented by the grooves 23 that are in contact with each other.

  In this way, the front and rear concrete boxes 4 are fastened only by the bolts 14 in the vicinity of the front and rear joining end faces. Therefore, it is not necessary to use a binding member such as a long PC steel bar, which is effective for curved construction.

It is a vertical side view which shows embodiment of the binding method of the concrete box in the open shield method of this invention. It is a vertical side view of the principal part which shows embodiment of the binding method of the concrete box in the open shield method of this invention. It is a side view which shows the 2nd example of the loosening prevention means used with the binding method of the concrete box in the open shield method of this invention. It is a partial explanatory view showing a second example of the loosening prevention means used in the method for binding concrete boxes in the open shield method of the present invention. It is other one part explanatory drawing which shows the 2nd example of the loosening prevention means used with the binding method of the concrete box in the open shield method of this invention. It is a vertical side view which shows the outline of an open shield construction method. It is a perspective view of a concrete box. It is a perspective view of the concrete box used with the conventional binding method. It is a vertical side view which shows the binding method of the conventional concrete box.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Open shield machine 1a Side wall board 1b Bottom board 1c Tail part 1d Front part 2 Shield jack 3 Bulkhead 4 Concrete box 4a Left side board 4b Right side board 4c Upper floor board 4c Lower floor board 5 Backfill soil 6 Grout material 7 Height adjustment material 8 Press Bar 9 Excavator 10 Opening
DESCRIPTION OF SYMBOLS 11 Cutting edge 12 Insert 13 Breath bar 14 Tightening bolt 15 Box removal 16 Nut 17 Nord-lock washer 18 Washer 19 Fixing plate 20 Wedge washer 20a 20b Wedge body 21 Long hole 22 Round hole 23 Groove 31 Sheath hole 32 PC steel rod

Claims (4)

  The process of excavating and discharging soil in front of the front or top opening of the open shield machine, the process of extending the propulsion jack and advancing the shield machine with the concrete box as a reaction force, and shrinking in the tail part of the shield machine This is a method for binding concrete boxes in an open shield method in which a new concrete box is suspended from the upper side of the propulsion jack and set up by suspending it from above, and the concrete boxes are successively embedded in columns. Screw the bolt for tightening into the insert embedded in the joint end of the body in advance, the tip of the bolt protrudes forward from the joint end, and the next concrete box laid in front of the concrete box Insert the protruding end of the bolt, attach a nut here, and temporarily tighten it. It is propelled by reaction force, and with the axial compression force acting on the rear concrete box, the nut attached to the tip of the bolt is fully tightened and the concrete box at the front and back positions is tightened Tightening the concrete box in the open shield method.   The method for binding a concrete box in the open shield method according to claim 1, wherein means for preventing loosening are provided on the bolt for binding.   The method for binding concrete boxes in the open shield method according to claim 2, wherein the loosening prevention means is a Nord-Lock washer.   The method for binding concrete boxes in the open shield method according to claim 2, wherein the loosening prevention means is a pair of wedge washers.

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