Switching valve, concrete pouring device, and lining concrete pouring method

Abstract

To propose a switching valve, a concrete pouring device, and a lining concrete pouring method that enable reduction in the effort required for cleaning work.SOLUTION: A switching valve 5 includes a cylindrical body 51 connected to a formwork, and a sliding body 52 slidably inserted into the cylindrical body 51. The cylindrical body 51 is provided with a discharge port 511 opening at a tip of the cylindrical body 51, a sliding body inlet / outlet 512 opening at a rear end of the cylindrical body 51, and an inlet 513 and an outlet 514 opening at the side of the cylindrical body 51. The sliding body 52 is provided with an internal flow path 520 connecting the inlet 513 and the outlet 514 in a state where a tip surface of the sliding body 52 is aligned with a concrete side surface of the formwork. When the sliding body 52 is retracted until the tip surface of the sliding body 52 is positioned rearward of the inlet 513, at least the opening of the internal flow path 520 on the outlet 514 side is exposed rearward of the sliding body inlet / outlet 512.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a switching valve, a concrete placing device, and a method for placing covering concrete.

Background Art

[0002] As a method for placing covering concrete in a tunnel, there are cases where continuous construction is carried out using a movable formwork (slide centering) that moves in the tunnel axis direction. In the construction of covering concrete using a slide centering, concrete is poured with a concrete placing pipe inserted into a placing port formed in the slide centering. A plurality of placing ports are formed in the slide centering at intervals in the axial direction and the circumferential direction. During concrete placement, the concrete placing pipe is appropriately moved to each placing port. The movement of the concrete placing pipe from one placing port to another is carried out manually by workers. However, the work of manually moving the concrete placing pipe requires labor and time.

[0003] Therefore, Patent Document 1 discloses a switching valve that switches between a state of injecting concrete transported through a concrete transport pipe between the slide centering and the natural ground and a state of allowing it to flow downstream. The switching valve of Patent Document 1 includes a cylindrical body connected to the slide centering and a sliding body slidably housed in the cylindrical body. By sliding the sliding body within the cylindrical body, the pressure feeding destination of the concrete is switched.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Concrete transport pipes and switching valves need to be cleaned after the completion of concrete placement. However, in the switching valve of Patent Document 1, since the sliding body is housed inside the cylinder, it was necessary to disassemble the switching valve each time during cleaning, which was time-consuming. An object of the present invention is to propose a switching valve, a concrete placing device, and a formwork concrete placing method that can reduce the labor of cleaning work.

Means for Solving the Problems

[0006] The switching valve of the present invention for solving the above problems is interposed between an upstream pipe and a downstream pipe, and can switch between a state where the concrete supplied from the upstream pipe can be injected from a placing port formed in a formwork and a state where it can flow down to the downstream pipe. It includes a cylinder connected to the formwork and a sliding body slidably inserted into the cylinder. The cylinder is formed with an injection port that opens at the tip of the cylinder, a sliding body inlet / outlet that opens at the rear end of the cylinder, an inlet to which the upstream pipe is connected, and an outlet to which the downstream pipe is connected. The outlet is formed at a position offset in the axial direction of the cylinder with respect to the inlet. Further, an internal flow path that connects the inlet and the outlet is formed in the sliding body in a state where the front end surface of the sliding body coincides with the surface of the formwork on the concrete side. When the sliding body is retracted until the front end surface of the sliding body is located behind the inlet, at least the opening on the outlet side of the internal flow path is exposed behind the sliding body inlet / outlet.

[0007] In addition, the concrete placing device of the present invention includes a slide centor formed by combining a plurality of formwork members, a concrete pump for pumping fresh concrete, a concrete placing pipe extending from the concrete pump and piped along the inner surface of the slide centor, and a plurality of switching valves connected via the concrete placing pipe. The plurality of switching valves are provided at intervals in the circumferential direction on the inner surface of the slide centor.

[0008] The method for placing the concrete for the lining of the present invention using this concrete placing device includes a mounting step of installing the slide centering device and a placing step of pouring concrete between the slide centering device and the inner surface of the tunnel. In the placing step, a lower injection operation is performed in which the sliding body of the lower switching valve, which is the lower switching valve, is retracted and concrete is injected from the lower switching valve, and an upper injection operation is performed in which the sliding body of the upper switching valve, which is the switching valve disposed above the lower switching valve, is retracted and concrete is injected from the upper switching valve. In the upper injection operation, the sliding body of the lower switching valve is advanced to connect the internal flow path of the lower switching valve to the inlet and the outlet, and the concrete is guided to the upper switching valve.

[0009] According to such a switching valve, a concrete placing device, and a method for placing the lining concrete, by injecting high-pressure water into the gap between the sliding body and the cylinder body in a state where the sliding body is retracted, the inside of the switching valve can be cleaned. The high-pressure water injected into the gap is discharged from the sliding body inlet / outlet of the cylinder body. Therefore, even when a part of the concrete (for example, cement milk, mortar, etc.) penetrates between the cylinder body and the sliding body, it can be cleaned. Further, it is possible to clean the internal flow path from the opening of the internal flow path exposed by retracting the sliding body.

[0010] In addition, if ridges are formed on the side surface of the sliding body along the axial direction of the cylinder body, a gap between the cylinder body and the sliding body is ensured, and it becomes easier to clean. Further, if a recess or the like that engages with the ridge is formed at a position corresponding to the ridge of the cylinder body, the movement of the sliding body is suppressed. Also, if a cleaning hole is formed on the side surface of the cylinder body, high-pressure water can be injected between the cylinder body and the sliding body using the cleaning hole.

[0011] It is desirable that the switching valve includes a pair of jacks fixed to the side surface of the cylindrical body and a connecting member that connects the jacks and the rear end portion of the sliding body. By doing so, since the sliding body can be slid by the jacks, the concrete placing work can be performed more simply.

[0012] When the sliding body includes a housing that slides inside the cylindrical body and a flow path pipe that forms an internal flow path, it is desirable to form a welding hole on the side surface of the housing and weld the outer surface of this flow path pipe and the inner peripheral surface of the welding hole.

[0013] It is desirable that the concrete placing device includes a plurality of sensors that detect the placing state of the concrete and a control means that controls the sliding of the sliding body of the switching valve according to the detection result of the sensors. By doing so, the burden on the worker who monitors the concrete placing state can be reduced.

[0014] When the tip of the concrete placing pipe is connected to the opening of the slide centering at the upper part of the tunnel (for example, the shoulder, etc.), with the inlet and the outlet communicated by the internal flow path, a cleaning moving body (for example, a cleaning sponge) is pressure-fed into the concrete placing pipe, so that it is desirable to discharge the concrete in the concrete placing pipe from the tip of the concrete placing pipe between the slide centering and the inner surface of the tunnel. By doing so, all the concrete in the concrete placing pipe can be placed, and the amount of concrete waste can be reduced. The cleaning moving body discharged from the tip of the concrete placing pipe is collected from the window of the slide centering.

Advantages of the Invention

[0015] According to the switching valve, the concrete placing device, and the lining concrete placing method of the present invention, the labor for the cleaning work inside the switching valve can be reduced.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0017] In the present embodiment, an automatic placing technique for covering concrete will be described. For the construction of covering concrete, the concrete placing device 1 is used. The concrete placing device 1 is shown in FIGS. 1 and 2. As shown in FIGS. 1 and 2, the concrete placing device 1 includes a slide centering device 2, a concrete pump 3, a concrete placing pipe 4, a switching valve 5, a sensor 6, and a control means 7.

[0018] The covering concrete is formed by driving fresh concrete C between the slide centering device 2 installed in the tunnel pit and the natural ground G (sprayed concrete C1). The slide centering device 2 is formed in a cross-sectional arc shape (semicylindrical shape) corresponding to the cross-sectional shape of the tunnel T by combining a plurality of formwork members 21, 21,....

[0019] The formwork member 21 is rotatably connected to other formwork members 21 adjacent in the circumferential direction and can move in the tunnel diameter direction. That is, the slide center 2 can be reduced in diameter by moving the formwork member 21. Further, a confirmation window equipped with an opening / closing door is formed in the slide center 2, and it is configured to be able to confirm the placement status of the concrete. Note that the arrangement, shape, dimensions, etc. of the confirmation window are set as appropriate. A concrete placing pipe 4 for supplying fresh concrete C is piped on the inner space side of the slide center 2.

[0020] In addition, the slide center 2 is provided with a plurality of vibrators 22, 22, …. The vibrator 22 is fixed to the inner surface (the surface on the inner space side) of the slide center 2. The vibrator 22 imparts vibration to the concrete driven between the slide center 2 and the natural ground G. In this embodiment, a plurality of rows of vibrators 22 arranged at intervals in the tunnel circumferential direction are arranged in a plurality of rows in the tunnel axial direction. In this embodiment, the vibrator 22 is installed adjacent to the confirmation window formed in the formwork member 21. By doing so, the operator can confirm the compacting effect by the vibrator 22 from the confirmation window.

[0021] The concrete pump 3 pumps fresh concrete C through the concrete placing pipe 4. The concrete pump 3 is provided on the ground surface or in a shaft. The fresh concrete C pumped from the concrete pump is driven into the gap between the slide center 2 and the natural ground G through the concrete placing pipe 4.

[0022] The concrete placing pipe 4 extends from the concrete pump 3 and is piped along the inner surface of the slide center 2. The concrete placing pipe 4 of this embodiment is shown in FIG. 3. As shown in FIG. 3, the concrete placing pipe 4 of this embodiment includes a main pipe 41 extending from the concrete pump 3 to the base end of the slide center 2 and four branch pipes 42, 42, … branched through a branching means 43 provided at the base end of the slide center 2.

[0023] This pipe 41 has one end connected to the concrete pump 3 and the other end connected to the branching means 43, and transports the fresh concrete C pumped by the concrete pump 3 to the base end of the slide centering device 2.

[0024] The branch pipe 42 consists of a longitudinal pipe line 44 piped along the axial direction of the slide centering device 2 at the top of the slide centering device 2 and a transverse pipe line 45 piped along the circumferential direction of the slide centering device 2. The branch pipe 42 extends from the branching means 43 to a predetermined position by the longitudinal pipe line 44 and then extends in the circumferential direction by the transverse pipe line 45. Two of the four branch pipes 42, 42,... are provided with a transverse pipe line 45 piped at the base of the slide centering device 2 (one end in the tunnel axial direction), and the remaining two are provided with a transverse pipe line 45 piped at the tip of the slide centering device 2 (the other end in the tunnel axial direction). The transverse pipe line is shown in Fig. 4. As shown in Fig. 4, a plurality (two upper and lower stages in this embodiment) of switching valves 5, 5 are provided in the transverse pipe line 45 of the concrete placing pipe 4. Also, the tip 46 of the transverse pipe line is connected to the opening of the slide centering device 2 at the shoulder of the tunnel.

[0025] The plurality of switching valves 5 are connected via the concrete placing pipe 4 (transverse pipe line 45) and are provided at intervals in the circumferential direction on the inner surface of the slide centering device 2. The switching valve 5 switches the fresh concrete C supplied from the upstream side (concrete pump 3 side) via the concrete placing pipe 4 (upstream pipe) to a state where it can be discharged between the slide centering device 2 and the ground G and a state where it can flow down to the concrete placing pipe 4 (downstream pipe) connected to the downstream side (opposite side of the concrete pump 3).

[0026] Fig. 5 shows the switching valve 5. As shown in Figs. 5(a) and (b), the switching valve 5 includes a cylindrical body 51 connected to the slide centering device 2, a sliding body 52 slidably inserted into the cylindrical body 51, and a pair of jacks 53, 53 fixed to the side surface of the cylindrical body 51.

[0027] The cylinder body 51 is made of a steel member of the same material as the formwork member 21, presenting a square tube shape. The tip of the cylinder body 51 is fixed to the formwork member 21 of the slide center 2. The cylinder body 51 is formed with a discharge port 511 that opens at the tip of the cylinder body 51, a sliding body inlet / outlet 512 that opens at the rear end of the cylinder body 51, an inlet 513 that opens on the upper surface of the cylinder body 51, an outlet 514 that opens on the lower surface of the cylinder body, and a cleaning hole (not shown) that opens on the side surface of the cylinder body 51.

[0028] The discharge port 511 communicates with a through-hole formed in the formwork member 21. Further, the discharge port 511 (the tip of the cylinder body 51) has a shape that is flush with the surface of the formwork member 21 (the surface on the concrete side). The discharge port 511 and the sliding body inlet / outlet 512 have a shape that allows the sliding body 52 to be inserted therethrough. A concrete placing pipe 4 (upstream pipe) extending from the concrete pump P side (the upstream side in the transport direction) is connected to the inlet 513 (the connection part of the upstream pipe in this embodiment) (see Fig. 4). On the other hand, a concrete placing pipe 4 (downstream pipe) extending to the side opposite to the concrete pump P (the downstream side in the transport direction) is connected to the outlet 514 (the connection part of the downstream pipe in this embodiment) (see Fig. 4). The outlet 514 is formed at a position offset in the axial direction of the cylinder body 51 with respect to the inlet 513. In this embodiment, the inlet 513 is formed closer to the discharge port 511 side than the outlet 514. The outlet 514 is offset to the inner space side (the side opposite to the formwork member 21) with respect to the inlet 513 such that the outer (formwork member 21 side) edge is located on the inner space side of the inner space side edge of the inlet 513. That is, the inlet 513 and the outlet 514 are arranged so as not to overlap when projected onto a plane parallel to the central axis of the cylinder body 51. The cleaning hole (not shown) is formed below the outlet 514 and communicates with the gap between the cylinder body 51 and the sliding body 52.

[0029] The sliding body 52 is a rectangular parallelepiped member slidable inside the cylindrical body 51. An internal flow path 520 is formed in the sliding body 52. The internal flow path 520 connects the inlet 513 and the outlet 514 of the cylindrical body 51 in a state where the front end surface of the sliding body 52 coincides with the surface on the concrete side (the ground G side) of the formwork member 21 of the slide centering device 2. The sliding body 52 includes a housing 521 slidable inside the cylindrical body 51 and a flow path pipe 522 provided inside the housing 521. The flow path pipe 522 constitutes the internal flow path 520.

[0030] The housing 521 is made of a steel box-shaped member of the same material as the formwork member 21, and welding holes 523 are formed on the side surfaces. Further, protrusions 524 are formed on the left and right side surfaces of the housing 521 (the sliding body 52) along the axial direction of the cylindrical body 51 (the sliding direction of the sliding body 52). The protrusions 524 protrude from the side surfaces of the housing 521 and form steps on the side surfaces of the housing 521. The protrusions 524 are in contact with or close to the inner surface of the cylindrical body 51. Thereby, a gap is formed between the inner surface of the cylindrical body 51 and the left and right side surfaces of the sliding body 52. Note that grooves engaging with the protrusions 524 may be formed on the inner surface of the cylindrical body 51.

[0031] The flow path pipe 522 is arranged inside the housing 521 so as to communicate vertically, and the outer surface of the flow path pipe 522 and the inner peripheral surface of the welding hole 523 are welded. The flow path pipe 522 is bent in an S shape and constitutes the internal flow path 520 connecting the offset inlet 513 and the outlet 514. Further, when the sliding body 52 is retracted until the front end surface of the sliding body 52 is positioned behind the inlet 513, the flow path pipe 522 is arranged such that at least the opening on the outlet side of the internal flow path 520 (the upper end of the flow path pipe 522) is exposed behind the sliding body inlet / outlet 512.

[0032] A connecting member 54 for connecting a jack 53 is fixed to the rear end portion of the sliding body 52. The connecting member 54 includes a fixing portion 541 made of a steel plate fixed to the rear end of the housing 521 and a connecting portion 542 fixed to the fixing portion 541.

[0033] The jack 53 is a so-called hydraulic jack or air jack, which includes a main body 531 fixed to the side surface of the cylinder body and a rod 532 inserted into the main body 531 and supported so as to be able to advance and retreat. The tip of the rod 532 is connected to the connecting portion 542 of the connecting member 54. As shown in FIGS. 6(a) and 6(b), the sliding body 52 slides inside the cylinder body 51 as the jack 53 expands and contracts.

[0034] The sensor 6 detects the placement status of the fresh concrete C. In this embodiment, as the sensor 6, a placement detection sensor, a temperature sensor, and a pressure sensor are fixed at a plurality of locations on the slide centering device 2. The installation locations of each sensor 6 are determined as appropriate.

[0035] The placement detection sensor is fixed to the outer surface (the surface on the ground G side) of the formwork member 21, and detects the fresh concrete C driven between the slide centering device 2 and the ground G. By the placement detection sensor detecting the fresh concrete C, the placement status (placement height) of the fresh concrete C can be grasped.

[0036] The temperature sensor detects the temperature of the fresh concrete C during and after placement. Based on the temperature detected by the temperature sensor, the properties of the fresh concrete C can be grasped. Based on the temperature data of the fresh concrete C, the estimated strength of the concrete can be calculated.

[0037] The pressure sensor detects the load acting on the formwork member 21 of the slide centering device 2. Based on the detection result of the pressure sensor, the placement status of the fresh concrete C can be grasped. That is, based on the measurement result of the pressure sensor, the placement speed can be managed and the filling status at the top of the slide centering device 2 can be confirmed.

[0038] The data measured by each sensor 6 is automatically recorded in a cloud server or the like and transmitted to the control means 7. The control means 7 controls the operation of the concrete pump 3 and the sliding of the sliding body 52 of the switching valve 5 according to the detection results of each sensor 6. That is, the concrete placing device 1 determines the placing location of the fresh concrete C according to the fresh concrete placing situation. The switching valve 5 is actuated by a signal transmitted from the control means 7. Specifically, as a result of the jack 53 being actuated according to the signal transmitted from the control means 7, the sliding body 52 moves.

[0039] Hereinafter, a method for placing covering concrete by the automatic placing technique of the present embodiment will be described. The method for placing covering concrete using the concrete placing device 1 includes, as shown in FIG. 7, an installation step S1, a placing step S2, a pipe cleaning step S3, and a valve cleaning step S4.

[0040] In the installation step S1, the slide center 2 is installed in the tunnel pit. The slide center 2 is moved to a predetermined position in a state where the formwork member 21 is folded and the diameter is reduced. After the slide center 2 is arranged at the predetermined position, the diameter is expanded so as to have a predetermined shape (see FIGS. 1 and 2).

[0041] In the placing step, fresh concrete C is poured between the slide center 2 and the tunnel inner surface. The placing of the fresh concrete C is performed by connecting a concrete pump P to the concrete placing pipe 4 and pumping the fresh concrete C by the concrete pump P. In the placing step, a lower placement operation, an upper placement operation, a shoulder placement operation, and a top placement operation are performed.

[0042] In the lower-stage driving operation, as shown in Fig. 8, the slider 52 of the lower-stage switching valve 5a, which is the lower-stage switching valve 5, is retracted, and fresh concrete C is poured into the lower-stage switching valve 5a. The operation of opening the lower-stage switching valve 5a (the operation of retracting the slider 52) is performed according to a signal (first control signal) transmitted from the control means 7. When the slider 52 retracts, the tip surface of the slider 52 is disposed on the rear side (inside the tunnel) of the inlet 513. By doing so, while the inlet 513 remains open, the outlet 514 is closed by the slider 52, and the discharge port 511 is opened. Therefore, the fresh concrete C pumped through the concrete placing pipe 4 is discharged from the discharge port 511 and driven between the slide centering 2 and the natural ground G. When the sensor 6 detects that the fresh concrete C has been placed to a predetermined height, the slider 52 of the lower-stage switching valve 5a is advanced by a signal (second control signal) of the control means 7, as shown in Fig. 9, to shield the discharge port 511 of the lower-stage switching valve 5a and to communicate the inlet 513 and the outlet 514 by the internal flow path 520 of the lower-stage switching valve 5a. At this time, the fresh concrete C in the lower-stage switching valve 5a is pushed out to the slide centering 2 and the natural ground side as the slider 52 advances.

[0043] In the upper-stage driving operation, the slider 52 of the upper-stage switching valve 5b, which is the switching valve 5 disposed above the lower-stage switching valve, is retracted to open the discharge port 511 of the upper-stage switching valve 5b, and fresh concrete C is poured into the gap between the slide centering 2 and the natural ground G from the discharge port 511. The operation of opening the upper-stage switching valve 5b (the operation of retracting the slider 52) is performed in synchronization with the operation of closing the lower-stage switching valve 5a or according to a signal (third control signal) transmitted from the control means 7 after the second control signal. When the upper-stage switching valve 5b is open, the lower-stage switching valve 5a is in a state where the tip surface of the slider 52 coincides with the surface of the formwork member 21. When the sensor 6 confirms that the fresh concrete C has been placed to a predetermined height, the slider 52 is advanced by a signal (fourth control signal) from the control means 7 to shield the discharge port 511 of the switching valve 5.

[0044] In the shoulder placement operation, fresh concrete C is pumped while shielding the discharge ports 511 of the lower switching valve 5a and the upper switching valve 5b. When fresh concrete C is pumped with the lower switching valve 5a and the upper switching valve 5b closed, fresh concrete C is driven into the slide center 2 from the tip of the concrete placement pipe 4 installed at the shoulder (see Fig. 4). When it is confirmed by the sensor 6 that the fresh concrete C has been placed to a predetermined height, the concrete pump 3 is stopped and the pumping of the fresh concrete C is stopped by a signal (the fifth control signal) from the control means 7. Then, it is switched to a pipe (not shown) different from the concrete placement pipe 4, and fresh concrete C is driven into the slide center 2 from the top (top driving operation).

[0045] In this way, by driving fresh concrete C in order from the switching valve 5 on the upstream side (the concrete pump P side) of the concrete placement pipe 4, the back surface of the slide center 2 is filled with concrete. Incidentally, in parallel with the driving of the fresh concrete C, a vibrator 22 disposed near the switching valve 5 during the concrete driving operates to vibrate the formwork member 21 to compact the concrete.

[0046] In the pipe cleaning process S3, the concrete placing pipe 4 is cleaned. The pipe cleaning process S3 is performed, for example, before the top driving operation. In the pipe cleaning process S3, the slider 52 of each switching valve 5 is advanced to put the inlet 513 and the outlet 514 in communication with each other through the internal flow path 520. Further, the base end portion of the branch pipe 42 is removed from the branching means 43, and a cleaning moving body is pushed into the base end portion of the branch pipe 42. The cleaning moving body is a member that can slide inside the branch pipe 42, and is made of, for example, a columnar sponge (resin material) having an outer diameter equal to or larger than the inner diameter of the concrete placing pipe 4. Then, an air hose extended from the compressor is connected to the base end portion of the branch pipe 42, and the compressor is operated to pump the cleaning moving body. After passing through the concrete placing pipe 4 and the switching valve 5, the cleaning moving body is discharged from the tip of the concrete placing pipe 4. The discharged cleaning moving body is collected through the window of the slide centor 2.

[0047] In the valve cleaning process S4, the inside of the switching valve 5 is cleaned. In the valve cleaning process S4, with the slider 52 retracted, high-pressure water is jetted into the gap between the slider 52 and the cylinder body 51 from the cleaning hole of the cylinder body 51 to clean the gap. Further, the internal flow path 520 is cleaned from the opening of the internal flow path 520 exposed by retracting the slider 52.

[0048] According to the concrete placing device 1 and the formwork concrete placing method of the present embodiment, with the slider 52 retracted, high-pressure water is jetted into the gap between the slider 52 and the cylinder body 51, so that the inside of the switching valve 5 can be cleaned. The high-pressure water jetted into the gap is discharged from the slider inlet / outlet 512 of the cylinder body 51. Therefore, even when a part of the concrete (for example, cement milk, mortar, etc.) penetrates between the cylinder body 51 and the slider 52, it can be cleaned.

[0049] Also, by retracting the sliding body 52, it is possible to clean the internal flow path 520 from the exposed opening. Therefore, the cleaning work of the switching valve 5 is easy. Further, since the sliding body 52 (internal flow path 520) can be exposed by retracting the sliding body 52, it is also possible to perform maintenance (reinforcement, repair, etc.) on the sliding body 52.

[0050] In the concrete placing device 1 of the present embodiment, a switching valve 5 is provided in the concrete placing pipe 4 that transports fresh concrete C, and the concrete transported through the concrete placing pipe 4 can be directly guided to the back surface of the slide centering 2 (between the slide centering 2 and the natural ground G). Therefore, the amount of concrete remaining in the concrete placing pipe 4 can be reduced. Thus, the labor and cost required for disposing of the remaining concrete can be reduced. Further, since all of the fresh concrete C in the concrete placing pipe 4 is placed on the back surface of the slide centering 2 in the pipe cleaning process, the amount of concrete to be discarded can be reduced.

[0051] Further, since a protrusion along the axial direction of the cylindrical body 51 is formed on the side surface of the sliding body 52, a gap is ensured between the cylindrical body 51 and the sliding body 52, making it easier to clean. Also, by reducing the contact area between the sliding body 52 and the cylindrical body 51 by the protrusion, the frictional resistance during the sliding of the sliding body 52 can be reduced. If a recess or the like that engages with the protrusion is formed at a position corresponding to the protrusion of the cylindrical body, the movement of the sliding body 52 can be suppressed.

[0052] The switching valve 5 is provided with a pair of jacks 53 fixed to the side surface of the cylindrical body 51 and connected to the rear end portion of the sliding body 52. Therefore, the sliding body 52 can be automatically controlled to slide by the jacks 53, and the concrete placing work can be performed more simply.

[0053] Since a welding hole 523 is formed on the side surface of the housing 521 of the sliding body 52, the flow path pipe 522 can be welded using the welding hole 523. Therefore, the labor required for manufacturing the switching valve 5 can be reduced. Further, if the joint between the housing 521 and the flow path pipe 522 is cut at the welding hole 523, the flow path pipe 522 can be easily replaced.

[0054] Since the tip of the cylindrical body 51 and the tip surface of the sliding body 52 have a shape that is flush with the surface of the slide centering member 2 (the surface on the concrete side), it is difficult for traces (unevenness) of the placing hole to occur on the concrete surface. Therefore, after the slide centering member 2 is removed (after the construction of the covering concrete), the labor required for the repair work of the traces can be omitted or reduced.

[0055] Also, when finishing the injection of concrete by the switching valve 5, since the sliding body 52 is advanced toward the discharge port 511, it ends with the concrete in the cylindrical body 51 being extruded, so it is difficult for an air pocket to be formed near the discharge port 511. Therefore, the covering concrete can be constructed with higher quality. Further, since the inlet 513 is formed closer to the discharge port 511 than the outlet 514, when switching from the driving state of the fresh concrete C with the sliding body 52 advanced to the flowing-out state from the outlet 514, the amount of concrete extruded from the cylindrical body 51 can be minimized.

[0056] Since the placement status is detected by a plurality of sensors 6 and the injection location (switching valve 5) of the fresh concrete C is automatically moved, there is no need to visually confirm the placement status. Therefore, the labor of the worker can be reduced. Also, by automatically performing the compaction by the vibrator 22, the labor of the construction can be reduced. In this way, by mechanically performing the confirmation of the placement status and the compaction of the concrete, compared with the case of performing it manually, regardless of the skill level of the worker or the like, unevenness in the filling status of the concrete is less likely to occur.

[0057] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and each of the above-described components can be appropriately changed without departing from the spirit of the present invention. For example, in the above embodiment, the switching valve 5 is automatically operated according to the detection result of the sensor 6. However, the switching valve 5 may be manually operated by an operator or the like. When the switching valve is manually operated, the detection result of the sensor 6 may be displayed on a display means such as a lamp or a monitor, and the operator may check the display means and operate it.

[0058] In the above embodiment, the main pipe 41 connected to the concrete pump 3 is branched into a plurality of branch pipes 42, 42,... via the branching means 43. However, a plurality of concrete placing pipes 4 may be connected to different concrete pumps 3 respectively. Also, the number of the branch pipes 42 is not limited to four.

[0059] In the above embodiment, upper and lower two-stage ridges 524, 524 are formed on the left and right side surfaces of the sliding body 52. However, the number and arrangement of the ridges 524 are not limited. In the above embodiment, the case where the jack 53 is a cylinder jack has been described. However, the configuration of the jack 53 is not limited.

[0060] The piping of the concrete placing pipe 4 may be appropriately determined according to the shape of the tunnel or the like. Also, the number and arrangement of the switching valves 5 are not limited and may be appropriately determined. The tip of the cylindrical body 51 does not necessarily have to be flush with the surface of the formwork member 21 (the side on the ground G side). For example, it may be fixed to the inner surface of the formwork member 21 (the side on the inner cavity side). Also, the shape of the tip surface of the sliding body 52 is not limited. For example, it may be a flat surface.

[0061] In the above embodiment, the case where the flow path pipe 522 is S-shaped has been described. However, the shape of the flow path pipe 522 is not limited, and it may be a linear flow path inclined with respect to the moving direction of the sliding body 52 so as to connect the inlet 513 and the outlet 514. The inlet 513 and the outlet 514 may be formed in the cylindrical body 51 such that their central axes are parallel, or may be formed in a direction where the central axes intersect each other. The positional relationship between the inlet 513 and the outlet 514 is not limited and may be determined as appropriate.

Explanation of Signs

[0062] 1 Concrete placing device 2 Slide centering (formwork) 21 Formwork member 22 Vibrator 3 Concrete pump 4 Concrete placing pipe 41 Main pipe 42 Branch pipe 43 Branch means 44 Vertical pipeline 45 Horizontal pipeline 5 Changeover valve 51 Cylindrical body 511 Discharge port 512 Slide body inlet / outlet 513 Inlet 514 Outlet 52 Slide body 520 Internal flow path 521 Housing 522 Flow path pipe 523 Welding hole 524 Ridge 53 Jack 531 Main body part 532 Rod 54 Connecting member 541 Fixed part 542 Connecting part 6 Sensor 7 Control means C Fresh concrete G Natural ground

Claims

1. A switching valve interposed between an upstream pipe and a downstream pipe, capable of switching the state of the concrete supplied from the upstream pipe to be discharged from a placement opening formed in a formwork and the state of flowing down to the downstream pipe, comprising: a cylinder connected to the formwork; a sliding body slidably inserted into the cylinder; the cylinder has a discharge port opening at the tip of the cylinder; a sliding body inlet / outlet opening at the rear end of the cylinder; an inlet formed on the side surface of the cylinder and connected to the upstream pipe; an outlet formed on the side surface of the cylinder and connected to the downstream pipe; the outlet is formed at a position offset in the axial direction of the cylinder with respect to the inlet; the sliding body has an internal flow path formed therein that connects the inlet and the outlet with the front end surface of the sliding body being aligned with the concrete-side surface of the formwork; A switching valve, characterized in that when the sliding body is retracted until the front end surface of the sliding body is located behind the inlet, at least the opening on the outlet side of the internal flow path is exposed behind the sliding body inlet / outlet.

2. The switching valve according to claim 1, wherein a protrusion is formed on the side surface of the sliding body along the axial direction of the cylinder.

3. The switching valve according to claim 1, wherein a cleaning hole is formed on the side surface of the cylinder.

4. A pair of jacks fixed to the side surface of the cylinder; The switching valve according to claim 1, further comprising a connecting member connecting the jack and the rear end portion of the sliding body.

5. The sliding body includes a housing that slides inside the cylinder and a flow path pipe that constitutes the internal flow path; The switching valve according to claim 1, characterized in that a welding hole is formed on the side surface of the housing, and the outer surface of the flow path pipe and the inner peripheral surface of the welding hole are welded together.

6. A slide centering formed by combining a plurality of formwork members; A concrete pump for pumping fresh concrete; A concrete placement pipe extending from the concrete pump and arranged along the inner surface of the slide centering; A concrete placement device comprising a plurality of switching valves connected via the concrete placement pipe, wherein the switching valve is the switching valve according to any one of claims 1 to 5. The concrete placing device is characterized in that a plurality of the switching valves are provided at circumferential intervals on the inner surface of the slide centering device.

7. A plurality of sensors for detecting the placing state of concrete, and control means for controlling the sliding of the slider of the switching valve according to the detection result of the sensor, wherein the concrete placing device according to claim 6 is provided.

8. A method for placing lining concrete of a tunnel using the concrete placing device according to claim 6, including a installation step of installing the slide centering device, and a placing step of pouring concrete between the slide centering device and the inner surface of the tunnel, wherein in the placing step, a lower driving operation of retracting the slider of the lower switching valve, which is the lower-stage switching valve, and pouring the concrete from the lower-stage switching valve, and an upper driving operation of retracting the slider of the upper switching valve, which is the switching valve disposed above the lower-stage switching valve, and pouring the concrete from the upper-stage switching valve are performed, wherein in the upper driving operation, the slider of the lower-stage switching valve is advanced to connect the internal flow path of the lower-stage switching valve to the inlet and the outlet, and the concrete is guided to the upper-stage switching valve. The lining concrete placing method is characterized by this.

9. further including a valve cleaning step of cleaning the inside of the switching valve, wherein in the valve cleaning step, high-pressure water is injected into the gap between the slider and the cylinder body in a state where the slider is retracted. The lining concrete placing method according to claim 8 is characterized by this.

10. further including a valve cleaning step of cleaning the inside of the switching valve, wherein in the valve cleaning step, the inside of the internal flow path is cleaned from the opening of the internal flow path exposed by retracting the slider. The lining concrete placing method according to claim 8 is characterized by this.

11. further including a pipe cleaning step of cleaning the inside of the concrete placing pipe, wherein the tip of the concrete placing pipe is connected to the opening of the slide centering device at the upper part of the tunnel. In the pipe cleaning process, in a state where the inlet and the outlet are communicated with each other by the internal flow path, a cleaning moving body is pumped into the concrete placing pipe, so that the concrete in the concrete placing pipe is discharged from the tip of the concrete placing pipe between the slide centering device and the tunnel inner surface. The concrete placing method for lining concrete according to claim 8, characterized in that.

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