JP2016180211A - Inner mold, and construction method for tunnel having linear section and curved section - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endless inner mold that minimizes types of endless inner molds used even when a tunnel includes a linear section and a curved section, and to provide a construction method for the tunnel having a linear section and a curved section that significantly reduces construction costs compared to a conventional SENS method by using the inner mold.SOLUTION: Endless inner molds 1A, 1B have a plurality of pieces 1a, 1b assembled thereon, and are applied when constructing a tunnel having a linear section and a curved section by casting concrete C in a space K between a continuous body 2 and a natural ground G, the continuous body being made by connecting the endless inner molds 1A, 1B assembled inside a shield excavator 100. The endless inner molds 1A, 1B having a plurality of pieces 1a, 1b assembled thereon are trapezoidal in form when seen in a planar view from above, and include an endless inner mold, a narrow region R1 where a width thereof is relatively narrow, and a wide region R2 where a width thereof is relatively wide.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of constructing a tunnel having a straight section and a curved section, and an inner form frame applied to this method.

  While excavating a natural ground with a shield machine, the segments are assembled endlessly using the erector equipped with the excavator, and the excavated natural ground is supported by the segment ring, and a reaction force is applied to the segment ring. The shield construction method that constructs a segment tunnel by digging a shield machine and connecting segment rings in the longitudinal direction of the tunnel is widely applied mainly in urban areas.

  By the way, instead of forming a segment ring and constructing a tunnel lining while using this shield machine, a method of constructing a lining by placing concrete is currently attracting attention.

  In this method, an endless inner formwork is constructed inside the shield machine, a space is formed between the ground and the inner formwork created by excavation of the shield machine, and this space is filled with fresh concrete. It is in close contact with the natural ground, and a cast-in lining (lining) is constructed by curing. At this time, while stabilizing the face by excavating ground using a sealed shield machine, the cast-in lining was constructed behind the shield machine and this was the primary lining of the NATM method. It introduces the concept of construction method to be positioned in the same way. In this method, the primary lining supports the natural ground, confirms the stability of the tunnel, and then constructs a secondary lining that does not add a mechanical function as a waterproofing work to complete the tunnel. Note that this method uses the initial letter S for the Shield Tunnel Method, and the ECL method, which is a type of cast-in-place lining method. Therefore, since it is a system (System) consisting of three initial method theory, the initial N, it is sometimes referred to as a SENS method (a cast-in-place support system using a shield machine).

  And the tunnel construction method disclosed by patent document 1 can be mentioned as a conventional public technique regarding the said construction method.

  As described in Patent Document 1, by applying this construction technique (SENS construction method) and tunneling, the use of segments can be eliminated, and the concrete thickness of the primary lining can be reduced. It is possible to construct a tunnel more economically than when constructing a segment tunnel.

  By the way, in the construction method described above, a plurality of pieces (or curved pieces) are assembled in a shield machine instead of a segment ring to form an endless inner mold frame.

  This inner formwork consists of an arcuate (or curved) steel plate that is in close contact with the fresh concrete, and a plurality of main girders (the circumference of the steel plate) to support the steel plate and ensure the rigidity of the entire piece. It extends in the direction) and a frame made up of a web that connects the main girders.

  Although it is possible to realize economical construction because no segment is applied, a large number of pieces for the inner mold having the above-described configuration are newly used, and therefore, a production cost for that is generated. And if the tunnel to be constructed consists of only a straight section, the number of pieces may be small, but when attempting to construct a linear tunnel with a mixture of straight sections and curved sections using the SENS method Therefore, it is necessary to manufacture various types of pieces corresponding to the straight section and the curved section, and it is inevitable that the labor and cost of manufacturing the pieces become a problem.

JP 2006-241800 A

  The present invention has been made in view of the above-described problems, and in constructing a tunnel by applying a so-called SENS method, even if the tunnel has a straight section and a curved section, it is used endlessly. Compared to the conventional SENS method by using the inner mold that can greatly reduce the type of the inner mold (or the types of pieces constituting the inner mold) and the inner mold The object is to provide a method of constructing a tunnel with straight sections and curved sections that can make the construction cost much cheaper.

  In order to achieve the above object, an inner mold according to the present invention is an endless inner mold formed by assembling a plurality of pieces, and can be connected to the endless inner mold assembled in a shield machine. The inner formwork applied when constructing a tunnel with straight sections and curved sections by placing concrete in the space between the continuous body and the ground excavated by the shield machine, The endless inner mold frame formed by assembling a plurality of pieces has a trapezoidal shape when viewed from above, and the endless inner mold frame has a relatively narrow width. This is composed of a narrow region and a wide region having a relatively wide width.

  The inner formwork of the present invention is applied in the so-called SENS method described above, and more specifically, applied when constructing a tunnel having a straight section and a curved section by applying the SENS method. Is.

  A plurality of pieces are assembled endlessly to form a ring so as to correspond to a ground shape having a circular cross section excavated by a shield machine, and a plurality of rings are connected in the longitudinal direction of the tunnel. A continuum is formed, fresh concrete is placed in the space between the continuum and the natural ground, and it hardens to form a primary lining.

  The piece constituting the endless inner form is an arc shape (or curved shape) that is in direct contact with the fresh concrete, for example, a plate made of steel or stainless steel, and this arc plate is supported to ensure the rigidity of the whole piece. It can be comprised from the frame which consists of a some main girder (it extends in the circumferential direction of steel plates), a web etc. which connect main girder.

  Each piece constituting the ring can be composed of a large general piece that is relatively long in the circumferential direction and a small key piece that is relatively short in the circumferential direction. By providing a good small key piece, it becomes easy to remove the ring from this as a starting point.

  Here, the endless inner mold frame described above has a trapezoidal shape in plan view when viewed from above, a narrow region having a relatively narrow width, and a relatively wide width. It consists of a wide area.

  Since the tunnel to be constructed has a straight section and a curved section, when constructing a curved section, it corresponds to the narrow areas (and wide areas) of the endless inner formwork connected to each other in the shield machine By connecting the continuum as described above, it is possible to configure the continuum of the inner mold frame corresponding to the curved section curved in the edge direction formed by the connected narrow region.

  On the other hand, when constructing the straight section of the tunnel, when connecting the endless inner formwork in the shield machine, the other endless inner formwork is reversed with respect to one endless inner formwork, An endless inner mold having a rectangular shape in plan view made up of the two endless inner molds so that one of the wide areas and the other narrower area correspond to each other so that both ends are connected to each other. The continuum of

  Here, “rectangular” means not only a rectangle but also a square, and means a shape in which the corners of a quadrangle form a right angle in plan view.

  Note that the inner mold frame of the present invention, more specifically, the endless inner mold frame, becomes a ring-shaped inner mold frame when a tunnel lining with a circular cross section is constructed, and a plurality of pieces constituting the ring-shaped inner mold frame The piece is an arc-shaped piece having an arc surface. Further, the endless cross-sectional shape of the inner mold frame may have an appropriate cross-sectional shape such as a rectangle, a square, an ellipse, etc. in addition to the ring shape. For example, it forms an endless inner mold frame with a rectangular cross section. In the case of a plurality of pieces, an endless inner mold frame having a rectangular cross section is formed from a key-shaped piece that forms a corner, a linear piece that forms four sides, and the like. That is, if the shape of the endless inner mold frame when viewed from the top is trapezoidal, the plurality of pieces constituting the endless inner mold frame have an appropriate shape according to the cross-sectional shape. Is applicable.

  Two endless inner molds are mutually inverted (turned 180 degrees) and connected to form a rectangular inner mold unit in plan view. A continuum with multiple units connected is configured in a shield machine, and the space between the continuum and the ground is filled with concrete and hardened, so that the primary lining corresponding to the straight section is constructed on site. can do.

  In order to form a rectangular continuous body when two endless inner molds are connected to each other by being inverted, in fact, both endless inner molds are connected to the ring. The plan view shape when viewed from above needs to be a trapezoid in which two corners form a right angle.

  Therefore, if all the sections of the curved section and the straight section are to be constructed using only one type of endless inner formwork, the endless inner formwork has a plan view shape as described above. By applying an endless inner mold frame having a trapezoidal shape in which two corners form a right angle, the types of pieces to be manufactured can be remarkably reduced, and the construction cost can be greatly reduced.

  Further, the present invention extends to a method for constructing a tunnel having a straight section and a curved section, and this construction method includes an endless inner mold frame formed by assembling a plurality of pieces from above. The shape in plan view when viewed is a trapezoid, and the endless inner mold frame is composed of a narrow region having a relatively narrow width and a wide region having a relatively wide width. The inner formwork is assembled in the shield machine, and concrete is placed in the space between the continuous body formed by connecting the endless inner formwork and the natural ground excavated by the shield machine, and the straight section and the curved section are separated. In the method of constructing a tunnel provided, in a straight section, the two endless inner molds are inverted so that one of the wide regions and the other of the narrow regions correspond to each other. Inner formwork unit with a rectangular shape in plan view when connected Construct and form one or more inner formwork units, cast concrete between them and the ground, and wait for hardening to build a straight section tunnel. Without inverting the other when connecting the molds, the ends of the two adjacent inner molds correspond to each other so that both ends are connected to each other. It is implemented to form a continuous body of inner formwork, and concrete is placed between this and natural ground, and a tunnel in a curved section is constructed after hardening.

  The method for constructing a tunnel according to the present invention is to construct a tunnel having a straight section and a curved section by using the SENS method using the above-described inner formwork.

  In this construction method, as described above, an endless inner mold frame is applied to an inner mold frame having a trapezoidal shape in which two corners form a right angle in the plan view shape. It is possible to construct a tunnel in all sections of a straight section and a curved section using only the formwork.

  In the shield machine, for example, a plurality of pieces are assembled by an erector at the tail portion to form an endless inner formwork, which is connected in the longitudinal direction of the tunnel to form a continuous body of endless inner formwork Is done.

  The natural ground is excavated in a circular cross-section, for example, by the shield machine, a space is formed between the wall of the natural ground and the inner mold, and a wife mold is placed in this space from the shield machine. With the space completely closed, fresh concrete is placed in the closed space from the shield machine.

  At this time, the wife formwork is positioned by moving the wife formwork to the end of the space using the wife formwork jack equipped in the shield machine. For example, a steel seal brush is attached to the end formwork, and the seal brush can be in close contact with the surface of the inner formwork to ensure a sealing property when placing concrete.

  Furthermore, the above-mentioned wife formwork is provided with a concrete filling port, and a pipe communicating with the concrete mixer placed in the shield machine is attached to the concrete filling port, and fresh concrete is put into the defined enclosed space. Can be placed.

  After placing the concrete, in order to make the concrete adhere sufficiently to the natural ground, the concrete placed between the natural ground and the inner formwork is pushed in with the wife formwork jack and the space between the natural ground and the inner formwork is It is preferable to increase the density of concrete.

  After placing concrete and pressurizing it with a wife formwork jack, for example, the shield jack (propulsion jack) equipped on the shield machine pushes the inner formwork while applying a reaction force to the inner formwork, so The machine can be promoted.

  At this time, the thrust by the shield jack is first transmitted to the inner formwork, and this thrust is resisted by the adhesion force between the lining concrete and the inner formwork where a predetermined strength has been developed, The shield excavator is guaranteed to dig up against the frictional force and the compressive force in the tunnel longitudinal direction due to the already-constructed lining concrete on the wellhead side.

  In addition, when pressing the shield machine, press the press jack to pressurize the concrete at the same time as the shield machine uses the shield jack so that no voids are created in the enclosed space filled with concrete. Is also an effective means.

  When the shield machine was dug, and the primary lining of a certain length of extension was built in the process, the shield machine was equipped with an endless inner formwork that was left on the wellhead side and not yet removed. Demolding in order from the wellhead side by applying a demolding device.

  When removing the endless inner mold frame, as described above, in the general piece or key piece constituting the inner mold frame, the end portion in contact with another piece adjacent in the circumferential direction has a tapered shape. In particular, with regard to the key piece, when the inner mold is removed, it is first pulled out in the width direction of the inner mold, and the shape of the plan view is a trapezoid that widens toward the end in the drawing direction. The key piece can be easily removed in the longitudinal direction of the tunnel (in the direction of the wellhead), and then other general pieces and key pieces constituting the endless inner mold can be removed.

  The shield machine is equipped with transport means such as a rail that guides the movement of the carriage in the axial direction and a rail rack that guides the movement of the hoist, and the removed piece is placed on the face side in front of the shield machine. By transporting, it is possible to divert the transported piece when assembling a new endless inner mold.

  When the primary lining is constructed on site by the above method, after confirming the stability of the tunnel, for example, a secondary lining as a waterproof construction is constructed to complete the construction of the tunnel.

  As can be understood from the above description, according to the inner mold frame of the present invention and the method of constructing the tunnel having the straight section and the curved section using the inner mold frame, the number of types is reduced as much as possible. Endless inner formwork can be constructed by assembling pieces in the circumferential direction, connecting them in the longitudinal direction of the tunnel to form a continuous body, and placing concrete in the space between this continuous body and natural ground Since cast-in-place lining, which is a lining, can be constructed, it is possible to realize efficient assembly work of the inner formwork while reducing the production cost of the pieces for the inner formwork, thereby shortening the construction period. It is connected, and the tunnel provided with the straight section and the curved section can be efficiently constructed at the lowest possible construction cost while applying the SENS method.

It is the longitudinal cross-sectional view which simulated the shield machine applied with the construction method of the tunnel of this invention. It is the figure which showed both the front view at the time of regular assembly of an endless (ring shape) inner formwork, a top view, a bottom view, and a right and left side view. It is the figure which showed both the front view at the time of reverse-assembling an endless (ring-shaped) inner formwork, a top view, a bottom view, and a left and right side view. It is a top view of the continuous body of an endless inner form frame to the tunnel which consists of a straight section and a curve section. It is the schematic diagram which looked at the endless inner formwork from the tunnel inner side. (A) is a VI-VI arrow line view of FIG. 5, (b) is the figure explaining the method of connecting adjacent general pieces. It is a VII-VII arrow line view of FIG. It is a flowchart explaining the construction method of a primary lining in order of (a), (b), (c). It is an enlarged view of the IX section of Drawing 8a.

  Hereinafter, an embodiment of an inner mold of the present invention and a tunnel construction method to which the inner mold is applied will be described with reference to the drawings. The endless inner mold frame shown in the figure is a ring-shaped inner mold frame with a circular cross section, but the tunnel cross section may also be a tunnel with a rectangular cross section or an elliptical cross section. An endless inner mold is constructed by assembling pieces adapted to the above.

(About shield machine)
FIG. 1 is a longitudinal sectional view simulating a shield machine applied in the tunnel construction method of the present invention.

  A shield machine 100 shown in the figure is a hermetic shield excavator, and the machine body 30 is composed of a cylindrical front trunk 10 and a rear trunk 20, and the front trunk 10 is rear trunk by a not shown unfolded jack. 20 is configured so that it can be folded.

  A cutter head 12 is rotatably mounted on the bulkhead 11 of the front barrel 10, and a cutter pork (not shown) is fixed to the front surface of the cutter head 12 in a radial manner, for example, and a cutter bit is attached to the cutter pork. And a wide cutter (not shown) that can be expanded and contracted by a hydraulic jack in the radial direction of the cutter head 12 is mounted, and the wide cutter projects in a radial direction so as to have a circular cross section with a desired diameter. Tunnel excavation is possible.

  A screw conveyor 13 is disposed so as to penetrate from the front cylinder 10 to the rear cylinder 20, and the earth and sand excavated by the cutter head 12 is sent to the rear of the excavator body 30 and sent to the rear of the tunnel. The soil is discharged from the wellhead. That is, the outlet of the screw conveyor 13 passes through the lower part of the bulkhead 11 and communicates with the chamber chamber 14 defined by the cutter head 12 and the bulkhead 11, and the discharge port provided in the lower part behind the screw conveyor 13. Is opposed to a conveyor disposed in the longitudinal direction in the tunnel.

  A plurality of propulsion jacks 15 are arranged on the rear cylinder 20 rearwardly at a predetermined interval in the circumferential direction. Further, a plurality of wife mold jacks 16 are arranged on the inner wall surface of the rear cylinder 20. ing. The ends of the piston rods of the end form jacks 16 are hinged to end forms (ring-like) inner form frames 1A and 1B, which will be described later, and the end form frame 17 disposed in the inner wall surface of the rear barrel 20. ing.

  Further, a support member 21 is provided in the rear barrel 20, and a circular shape of the ring-shaped inner mold frames 1 </ b> A and 1 </ b> B assembled with the erector 22 that assembles the ring-shaped inner mold frames 1 </ b> A and 1 </ b> B on the support member 21. A shape holding device (not shown) for holding the posture is provided, and the rear barrel 20 further includes a demolding device 23 for demolding the inner mold frames 1A and 1B on the wellhead side, and an inner mold frame after demolding. A hoist rail 24 for transporting the piece to the face side and a hoist 25 for transporting the piece along the rail 24 are provided.

  When the shield machine 100 is dug, the propulsion jack 15 is extended while the cutter head 12 is rotated, and a plurality of ring-shaped inner molds 1A and 1B are assembled in the longitudinal direction of the tunnel. The cutter bit and roller cutter attached to the cutter head 12 excavate the front ground by taking the reaction force against the body 2 and the excavated earth and sand are transferred from the chamber chamber 14 to the outside via the screw conveyor 13. It is excavated.

  When the excavator main body 30 is dug, the ring-shaped inner mold frames 1A and 1B are assembled by the erector 22 and the shape holding device, and the true circle is held. As will be described later, in the space between the assembled ring-shaped inner molds 1A and 1B and the excavated tunnel ground G, fresh concrete is cast on-site from the casting opening opened in the wife mold 17. The primary lining is constructed by setting and curing after a certain curing period. Then, by repeating this construction, a tunnel having a predetermined length and a predetermined linear shape (primary lining) is constructed.

(Inner formwork and tunnel construction method)
FIG. 2 is a front view of the endless (ring-shaped) inner mold when assembled, a top view, a bottom view, and left and right side views. FIG. 3 is an endless (ring-shaped) ring. It is the figure which showed both the front view at the time of carrying out reverse assembly of the inner formwork of a shape, a top view, a bottom view, and a side view on either side.

  As shown in the figure when the inner mold frame of FIG. 2 is assembled, the positive ring-shaped inner mold frame 1A includes arc-shaped general pieces A1 to A8 and a key piece K1 disposed in the general piece. As shown in a top view when viewed from above, the shape in plan view is trapezoidal, the short side length is t1, the long side length is t2, and the two corner angles are It has a trapezoidal shape that forms a right angle.

  The right region having a short side length t1 in plan view forms a narrow region R1 in which the width of the inner mold frame is relatively narrow, and the left region having a long side length t2 in plan view has a relative width of the inner mold frame. Thus, a wide area R2 is formed.

  On the other hand, FIG. 3 is a view corresponding to FIG. 2 of the reverse-set ring-shaped inner mold 1B obtained by inverting (or moving 180 degrees) the forward-set ring-shaped inner mold 1A shown in FIG. It shows. In the reversely assembled ring-shaped inner mold 1B, as shown in the top view when viewed from above, the left side region having the short side length t1 in the plan view is the trapezoidal shape in the plan view. A narrow region R1 having a relatively narrow inner mold frame is formed, and a right region having a long side length t2 in plan view forms a wide region R2 having a relatively wide inner mold frame.

  The tunnel construction method of the present invention is to construct a tunnel by applying the shield machine 100 shown in FIG. 1 and using the SENS method (a cast-in-place support system using a shield machine). In the construction method, one type of ring-shaped inner mold 1A shown in FIGS. 2 and 3 and a ring-shaped inner mold 1B obtained by inverting the same are applied, and the entire tunnel having a straight section and a curved section is applied. The section is constructed.

  FIG. 4 is a plan view of a continuous body of an endless inner mold frame with respect to a tunnel composed of a straight section and a curved section.

  The plan view shown in the figure shows a continuous body of inner molds assembled in a ring shape in a shield machine not shown in the straight section and the curved section along the axis L of the tunnel to be constructed. It is. That is, in the figure, illustration of the shield machine is omitted for easy understanding.

  First, in the straight section, one of the two ring-shaped inner molds is a normal inner frame 1A, the other is a reverse inner mold 1B obtained by inverting the normal set, and one wide region R2 The inner mold unit 2A having a rectangular shape in a plan view in which both ends are connected so as to correspond to the other narrow region R1 is configured, and one or more (three sets in FIG. 4) are connected. The inner frame of the straight section is configured with.

  That is, as shown in FIGS. 2 and 3, since it is a ring-shaped inner mold frame 1A, 1B having a trapezoidal shape in plan view, an inner mold unit 2A having a rectangular shape in plan view can be configured as shown in FIG. It is possible to form a continuum of inner mold frames corresponding to the straight section by connecting the same number of sets according to the desired straight section length.

  On the other hand, in a curved section that shifts from a straight section to a curved section and curves to the right in a plan view as in the illustrated example, a continuous body 3 is formed by continuously connecting a pair of ring-shaped inner molds 1A. .

  In the case of a curved section that curves to the left side, a continuous body may be formed by continuously connecting the reverse inner ring-shaped frame 1B, and in the case of a curved section that curves in a zigzag direction in the left-right direction, What is necessary is just to comprise the continuous body of the inner mold frame of a corresponding curve area, mixing a normal group and a reverse group suitably.

  As described above, according to the illustrated ring-shaped inner mold 1A (and the inner mold 1B obtained by inverting the ring-shaped inner mold 1B), one kind of ring-shaped inner mold has a straight section and a curved section for tunnel construction. It becomes possible to constitute a continuous body of the inner mold. And since this one type of ring-shaped inner form can be composed of 12 types of general pieces A1 to A8 and key pieces K1 to K4, straight and curved sections are mixed with very few types of arc-shaped pieces. It is possible to configure the inner formwork of the entire section of the tunnel.

  In addition, in the case of having two or more curved sections having different curvatures, two or more types of inner mold frames of a trapezoidal ring in plan view may be prepared. Alternatively, when the positive inner ring form is connected to the positive ring inner form frame, the curvature of the tunnel can be adapted by rotating the inner die frame connected later around the ring center. Further, the endless inner mold is not limited to the circular shape in the illustrated example, and any cross-sectional shape such as a cross-sectional ellipse, a cross-sectional rectangle, or a cross-sectional rectangle can be applied. The shape form of the general piece or key piece corresponding to the endless shape is applied.

  5 is a schematic view of the endless inner formwork as seen from inside the tunnel, FIG. 6a is a view taken along arrow VI-VI in FIG. 5, and FIG. 7 is a view taken along arrow VII-VII in FIG. is there.

  As shown in FIGS. 5 and 6a, the general piece 1a constituting the inner frame is composed of a steel or stainless steel plate 1a1 that forms an arcuate surface along the tunnel cross section, a main girder 1a2 erected from the plate 1a1, It is comprised from the web 1a3 which connects between the digits 1a2 and 1a2.

  6b, as shown in FIG. 6b, the sleeve 1a4 is fitted into the bolt holes 1a2 'opened in both the main girders 1a2 and 1a2, the tapered piece 1a5 is fitted into the sleeve 1a4, and the washer 1a6 is interposed. Then, the bolts 1a7 are inserted and tightened with the nuts 1a8 to join the two.

  On the other hand, as shown in FIG. 7, the key piece 1b includes a steel plate 1b1 having an arcuate surface, a stainless plate 1b4 which is surface-bonded to the steel plate 1b1, and a main girder 1b2 standing from the steel plate 1b1. The web 1b3 connects the main girders 1b2 and 1b2.

  Further, the key piece 1b is provided with two hydraulic jacks 1b5 and 1b5. When removing the ring-shaped inner mold on the wellhead side, first, the keyhole 1b is not inserted into the gripping hole 1b3 ′ opened in the web 1b3. The illustrated removal jig is inserted, the bolt is loosened, the hydraulic jack 1b5 is operated while applying a reaction force to the ring-shaped inner mold on the face side, and the key piece 1b is pulled out to the wellhead side (X in FIG. 5). direction).

  Here, as shown in the figure, in the general piece 1a and the key piece 1b, the end portion in contact with a separate piece adjacent in the circumferential direction has a tapered shape, and in particular, the inner frame is removed from the key piece 1b. When it is done, it is first pulled out in the width direction of the inner formwork, and the shape in plan view is a trapezoid that spreads out in the drawing direction (X direction), so the longitudinal direction of the tunnel (in the wellhead direction) In addition, the key piece can be easily removed from the mold, and thereafter, other general pieces and key pieces constituting the endless inner mold can be removed.

  When one key piece 1b is pulled out, other ring-shaped general pieces and key pieces are sequentially pulled out to complete the demolding of the ring-shaped inner mold.

  Next, referring to FIGS. 8 and 9, a space between the ground G cut by the shield machine 100 and the ring-shaped inner formwork unit 2 </ b> A and the continuous body 3 assembled in the shield machine 100. Outlines how to place concrete in

  FIG. 8 is a flowchart for explaining the primary lining construction method in the order of FIGS. 8a, b, and c, and FIG. 9 is an enlarged view of the IX portion of FIG. 8a.

  The natural ground G is excavated in a circular cross section by the shield machine 100, and between the natural ground G, the skin plate 20a behind the rear trunk 20 of the shield machine 100, and the ring-shaped inner mold 1A. A space K is formed, and in this state where a wife form 17 extending from the wife form jack 16 is disposed in the space K from within the shield machine 100, the space K is completely closed, and the shield dig is entered in the closed space K. Fresh concrete C is placed from inside the machine 100.

  Here, the wife formwork 17 is moved to the end of the space K by the wife formwork jack 16 provided in the shield machine 100 and positioned. For example, a steel seal brush 17b is attached to the end form frame 17, and the seal brush 17b is in close contact with the surfaces of the ring-shaped inner form frames 1A and 1B to provide a sealing property when placing concrete. It comes to secure.

  The formwork 17 is provided with a concrete filling port 17a, and a pipe communicating with a concrete pump (not shown) placed in the shield machine 100 is attached to the concrete filling port 17a to define a closed space. Fresh concrete C can be placed in K.

  After placing the concrete C, the concrete C placed between the natural ground G and the ring-shaped inner molds 1A and 1B is applied to the shield machine 100 so that the concrete C is sufficiently adhered to the natural ground G. It is preferable to push in with the equipped wife formwork jack 16 to make the concrete C between the natural ground G and the ring-shaped inner formwork 1A, 1B dense.

  After placing concrete C and pressurizing it with the wife formwork jack 16, the propulsion jack 15 mounted on the shield machine 100 applies the reaction force to the ring-shaped inner formwork 1A on the face side while taking the reaction force into the ring. It is possible to push the shield machine 100 by pushing the inner mold 1 </ b> A in the shape of the wellhead side.

  At this time, the thrust by the propulsion jack 15 is first transmitted to the continuous body of the ring-shaped inner molds 1A and 1B, and this thrust is applied to the lining concrete C and the ring-shaped inner molds 1A and 1B exhibiting a predetermined strength. The shield digging machine 100 digs against the frictional force of the lining concrete C and ground G and the compressive force in the tunnel longitudinal direction by the lining concrete C on the wellhead already constructed. Is guaranteed. Then, a new inner mold 1A is assembled in the space on the face side of the continuous form of the inner mold formed by this excavation (see FIG. 8b).

  In addition, when the shield machine 100 is excavated, the wife form jack 17 is operated simultaneously with the excavation of the shield machine 100 by the propulsion jack 15 so that no gap is generated in the closed space K filled with the concrete C. It is also an effective method to pressurize the concrete C.

  In this way, the primary lining is constructed on site in the entire tunnel between the straight section and the curved section, and the secondary lining concrete is constructed on the inside to complete the tunnel.

  According to the tunnel construction method of the present invention described above, even if the tunnel to be constructed has a straight section and a curved section, as few pieces as possible are assembled in the circumferential direction to form a ring shape. The inner formwork can be configured, and this is connected to the longitudinal direction of the tunnel to form a continuous body, and concrete is cast in the space between the continuous body and the natural ground, and the cast-in-place lining that is the primary lining is constructed. be able to. Therefore, it is possible to realize the efficient assembly work of the inner formwork while reducing the production cost of the pieces for the inner formwork, thereby shortening the construction period, and applying the SENS method, the straight line Tunnels with sections and curved sections can be constructed efficiently with the lowest possible construction cost.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

1A ... Endless inner formwork (normal assembly), 1B ... Endless inner formwork (reverse assembly), 1a, A1 to A8 ... General piece, 1a1 ... Arc plate, 1a2 ... Main girder, 1a3 ... Web, 1b , K1 to K4 ... keypiece, 1b1, 1b4 ... arc plate, 1b2 ... main girder, 1b3 ... web, 1b3 '... gripping hole, 1b5 ... hydraulic jack, 2 ... continuous body, 2A ... endless inside corresponding to the straight section Formwork unit, 3 ... a continuous body of endless inner formwork corresponding to a curved section, 10 ... front trunk, 15 ... propulsion jack, 16 ... wife formwork jack, 20 ... rear trunk, 30 ... main body of excavator, 100 ... Shield machine, R1 ... Narrow area, R2 ... Wide area, G ... Mt.

Claims (8)

An endless inner formwork formed by assembling a plurality of pieces, a continuous body formed by connecting the endless inner formwork assembled in a shield machine, and a natural ground excavated by the shield machine It is an inner formwork applied when constructing a tunnel with straight sections and curved sections by placing concrete in the space between,
The endless inner mold frame formed by assembling a plurality of pieces has a trapezoidal shape when viewed from above, and the endless inner mold frame has a relatively narrow width. An inner mold frame composed of a narrow region and a wide region having a relatively wide width.   The plan view shape of the continuous body in which the two endless inner molds are reversed so that one of the wide regions and the other narrow region correspond to each other and the ends thereof are connected to each other is rectangular. Item 2. An inner mold according to Item 1.   The inner mold according to claim 1 or 2, wherein the endless inner mold is a ring-shaped inner mold. The endless inner mold frame formed by assembling a plurality of pieces has a trapezoidal shape when viewed from above, and the endless inner mold frame has a relatively narrow width. An inner formwork composed of a narrow area and a relatively wide area is assembled in a shield machine and excavated with a continuum made up of endless inner formwork and a shield machine. In the method of constructing a tunnel with straight sections and curved sections by placing concrete in the space between the ground
In the straight section, the two endless inner mold frames are reversed, and the shape of the plan view in a posture in which both ends are connected so that one wide region and the other narrow region correspond to each other is rectangular. The inner formwork unit is formed, one or more inner formwork units are formed, concrete is placed between this and the ground, and a tunnel in a straight section is constructed after waiting for hardening.
In the curved section, when connecting adjacent endless inner molds, without inverting the other, both ends are connected so that the wide regions of both adjacent inner molds correspond, A straight section that is implemented with two or more endless inner forms to form a continuous body of inner forms, put concrete between this and the ground, wait for it to harden, and build a curved section tunnel How to build a tunnel with curved sections.   The method for constructing a tunnel having a straight section and a curved section according to claim 4, wherein construction of the entire section of the tunnel is performed only with one kind of the endless inner formwork.   The method for constructing a tunnel having a straight section and a curved section according to claim 4 or 5, wherein the endless inner form is a ring-shaped inner form.   A tunnel having a straight section and a curved section according to any one of claims 4 to 6, wherein a shield jack mounted on the shield machine takes a reaction force on an endless inner formwork to carry out the shield machine. How to build.   Along with the excavation of the shield machine, the endless inner formwork used in advance is removed into multiple pieces, transferred to the face side inside the shield machine, diverted, and a new endless form The method for constructing a tunnel having a straight section and a curved section according to any one of claims 4 to 7, wherein the inner formwork is assembled.

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