Method for constructing lining concrete

Abstract

This invention provides a method for constructing concrete lining that reduces the labor required for the construction of concrete lining, shortens the working time, and reduces the number of personnel involved in the work, especially skilled workers, thereby improving productivity. [Solution] In a method for constructing the lining concrete of a mountain tunnel by pressurizing concrete into a movable formwork consisting of a side wall, shoulder, and top section, the concrete is self-filling concrete, and the concrete is pressurized from only an injection port provided at the lower part of the side wall to the entire area from the side wall to the top section.

Description

Technical Field

[0001] The present invention relates to a method for constructing lining concrete using a mobile formwork (slide centering) at a mountain tunnel construction site.

Background Art

[0002] In mountain tunnel construction, a method for constructing lining concrete is known to prevent weathering, spalling, etc. of the ground (rock mass, etc.) at the excavation face. As a means for constructing this lining concrete, a means using a mobile formwork (slide centering) is common, and a method of injecting and filling concrete between this mobile formwork and the ground to construct lining concrete is adopted.

[0003] When constructing this lining concrete, at the current construction site, concrete is injected through inspection windows provided in the mobile formwork, and workers lean out of the inspection windows to perform tamping work with a vibrator. Since the concrete is driven in order from the bottom, when the concrete is filled to a certain height, this injection and tamping work needs to move in order from the bottom to the upper inspection window. Specifically, inspection windows are provided at regular intervals from the lower part to the upper part of the formwork, and the tip of the concrete pumping pipe needs to be moved upward in order, and at the same time, the tamping work also needs to move to the upper inspection window.

[0004] Since it is necessary to move the tip of the pumping pipe in order, the concrete driving takes time due to switching work and the like. Regarding the tamping work, in addition to taking time as in driving, there is a problem that the burden on workers is large because they are forced to work in a narrow space. Also, this tamping work requires skilled techniques, and it is necessary to secure such skilled workers.

[0005] The invention described in Patent Document 1 addresses the problem of "simplifying the compaction work of poured concrete and achieving high-quality construction," and proposes a tunnel construction method comprising "a step of compacting fresh concrete by vibration of vibrators installed in multiple stages on a slide centerer, wherein the compaction at the top is performed at a higher operating frequency than at the side walls."

[0006] However, the technology described in Patent Document 1 has the problem that it does not significantly reduce the time required for compaction, and the process of installing multiple compaction vibrators in parallel is complicated.

[0007] Incidentally, the construction industry is facing problems due to its declining workforce and aging population. In particular, the decline in skilled workers continues, and combined with the aforementioned aging problem, the transfer of technical skills to the next generation is a major challenge. In addition to this situation, the so-called "2024 problem" makes it unavoidable to reduce working hours per person, and improving productivity is essential for construction work at mountain tunnel construction sites. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2013-163965 [Overview of the project] [Problems that the invention aims to solve]

[0009] Therefore, the object of the present invention is to provide a method for constructing concrete lining that can improve productivity by reducing the labor required for the construction of concrete lining, thereby shortening the working time and reducing the number of personnel, especially skilled workers, involved in this work. [Means for solving the problem]

[0010] The object of the present invention described above is achieved by the following means.

[0011] 1. In a method for constructing the lining concrete of a mountain tunnel by injecting concrete into a movable formwork consisting of side walls, shoulders, and top sections, The aforementioned concrete is self-compacting concrete, A method for constructing lining concrete, characterized in that the concrete is injected into the entire area from the side wall to the top surface, using only an injection port provided at the lower part of the side wall.

[0012] 2. The method for constructing lining concrete according to claim 1, characterized in that at least one injection port is provided at the lower part of each of the left and right side walls, and concrete is injected through a total of two or more injection ports on both sides.

[0013] 3. The method for constructing lining concrete according to claim 1 or 2, characterized in that two pressure inlets are provided at the lower part of each of the left and right side walls, one near the end of the lap side and the other in the central part between the lap side and the toe side.

[0014] 4. After confirming that the concrete injected from the injection port has reached all formwork surfaces, The method for constructing lining concrete according to claim 3, characterized in that the central injection inlets in both the left and right side walls are closed, and the lap-side injection inlet in either the left or right side wall is closed, and concrete is injected through the remaining single injection inlet to fill the movable formwork with the concrete.

[0015] 5. The configuration is such that the status of concrete reaching the formwork surface is determined by a filling detection sensor that senses the arrival of concrete. The filling detection sensors are installed horizontally in parallel near the toe end, near the wrap end, and in the center between these two points. These three horizontally parallel-mounted fill detection sensors form a set. Multiple sets of the aforementioned filling detection sensors are installed in parallel at equal intervals from the side wall to the top surface, and they determine the horizontal position where concrete filling is complete. The method for constructing lining concrete according to claim 4, characterized in that when all of the installed filling sensing sensors sense the arrival of the concrete, it is confirmed that the concrete has reached all of the formwork surfaces.

[0016] 6. The method for constructing lining concrete according to claim 5, characterized in that the difference in the height of the concrete poured on the left and right sides is controlled to 500 mm or less based on information obtained from filling sensing sensors installed at equal intervals from the side wall to the top surface.

[0017] 7. In order to understand the status of concrete filling in each part of the movable formwork, a pressure sensor is installed to detect the pressure acting on the formwork. The pressure sensors are installed near the toe end, near the lap end, and in the center between them at the lower part of the left and right side walls, as well as near the toe end, near the lap end, and in the center between them at the top of the top surface. The method for constructing lining concrete according to claim 6, characterized in that the filling status of the concrete is determined by the pressure value detected by the pressure sensor.

[0018] 8. The filling detection sensor is in the shape of a sheet. The aforementioned sheet-like filling sensing sensor is installed on the top of the ground located above the top of the top end of the movable formwork, in a configuration that extends from near the end on the toe side to near the end on the lap side. A sheet-shaped filling detection sensor detects when concrete is reached. The method for constructing lining concrete according to claim 7, characterized in that all pressure sensors indicate a pressure value corresponding to a predetermined lining thickness, and the concrete injection is terminated when the pressure sensor installed near the toe end reaches 1.5 times the pressure value indicating the predetermined lining thickness.

Advantages of the Invention

[0019] According to the first aspect of the invention, by using self-compacting concrete as the concrete to be pressed into the mobile formwork, the compaction work by a vibrator becomes unnecessary. Thereby, the work can be labor-saving, so the working time can be shortened. Furthermore, since the number of personnel required for the compaction work can be reduced, the personnel engaged in this work, especially skilled workers, can be downsized.

[0020] Also, according to the first aspect of the invention, since the concrete is pressed into the entire range from the side wall portion to the top end portion only through the pressure inlet provided at the lower part of the side wall portion of the mobile formwork, the work of moving the tip of the concrete delivery pipe, which was conventionally carried out, becomes unnecessary. Thereby, the personnel engaged in the movement of the tip can be downsized, and the working time can also be shortened.

[0021] As described above, the productivity in the construction of the covering concrete can be improved by the effects of shortening the working time due to labor-saving of the work and labor-saving of personnel (especially skilled workers).

[0022] According to the second aspect of the invention, since at least one pressure inlet is provided at the lower part of each of the left and right side wall portions, and a total of two or more pressure inlets are provided on the left and right, the concrete can be evenly pressed in from the left and right side wall portions, and the balance of the driving height (the level at which the filling of the concrete is completed) on the left and right can be maintained.

[0023] According to the third aspect of the invention, by installing pressure inlets near the end portion and the central portion on the lap side, the concrete pressed in from these pressure inlets can be spread over the entire area from the lap side to the toe side. Furthermore, it is possible to select to open only the pressure inlet on the lap side, and if necessary, it is also possible to spread the concrete from the lap side to the toe side.

[0024] According to the invention described in item 4 above, once the concrete injection into the top surface has reached a certain stage, the injection can be switched to injection from only one injection port on either the left or right side of the lap side (a so-called "single-sided injection" state), thereby promoting the filling of concrete into the toe end. Furthermore, by switching to this single-sided pressure system only after the concrete has reached all formwork surfaces, it is possible to prevent the concrete from hardening and blocking the inside of the pumping pipe connected to the closed pressure inlet.

[0025] According to the invention described in item 5 above, by installing multiple sets of filling detection sensors in parallel at equal intervals, the horizontal position (pour height) at which concrete filling is completed can be accurately determined. Furthermore, by installing filling detection sensors from the side walls to the top surface, it is possible to confirm that the injected concrete has reached all surfaces of the formwork.

[0026] According to the invention described in 6 above, the difference in concrete pouring height between the left and right formwork can be controlled to a predetermined height by information obtained from filling sensing sensors installed at equal intervals from the side wall to the top surface.

[0027] According to the invention described in item 7 above, by installing pressure sensors near the toe end, the lap end, and the central part at the lower part of the left and right side walls, and near the toe end, the lap end, and the central part at the top of the top surface, the concrete filling status can be determined by the pressure values ​​detected by the pressure sensors.

[0028] According to the invention described in item 8 above, a sheet-shaped filling sensing sensor installed at the top of the ground detects the arrival of the concrete, making it possible to confirm that the concrete has reached the top of the void between the formwork and the ground (the space to which the concrete is to be poured). Furthermore, the concrete filling can be confirmed by having all pressure sensors indicate a pressure value corresponding to a predetermined lining thickness obtained through prior calculation. Furthermore, when a pressure sensor installed near the toe end reaches 1.5 times the pressure value corresponding to the predetermined lining thickness, it can be confirmed that the concrete filling is sufficient. By confirming these three points, it can be determined that the necessary lining concrete has been constructed, and thus the concrete pouring process can be considered complete. [Brief explanation of the drawing]

[0029] [Figure 1] A schematic diagram showing one embodiment of the movable formwork according to the present invention. [Figure 2] A schematic diagram illustrating the horizontal positions of the lap side, center, and end of the formwork. [Figure 3] A schematic diagram showing how the carving is done in the order of side wall, shoulder, and top surface. [Figure 4] A schematic diagram showing how concrete is injected into the side walls and shoulders. [Figure 5] A schematic diagram showing how concrete is injected into the top surface. [Figure 6] A schematic diagram illustrating the timing of the transition to single-sided pressing. [Figure 7] Schematic diagram showing the installation location of the fill detection sensor. [Figure 8] Schematic diagram showing the installation location of the pressure sensor. [Modes for carrying out the invention]

[0030] Embodiments of the present invention will be described in detail with reference to the attached drawings. Figure 1 is a schematic diagram showing one embodiment of a movable formwork 1 used to implement the method for constructing lining concrete according to the present invention.

[0031] A movable formwork is an arch-shaped formwork used in tunnel construction for the construction of lining concrete (concrete pouring). It is a type of formwork that can be moved and set up repeatedly on rails without being disassembled, allowing for successive concrete pouring. It is commonly referred to as a slide center or simply a center. There are no limitations on the basic configuration of the movable formwork 1 according to the present invention, and publicly known and publicly available configurations can be adopted without any special restrictions.

[0032] The movable formwork 1 shown in Figure 1 is configured to be movable on rails 6 by a gantry 5. At the bottom of the arch-side formwork, there is an inlet 2, which is an opening for pumping and injecting concrete into the movable formwork 1 from the outside via a pumping pipe 3. There are no limitations on the basic configuration of the gantry 5, rails 6, or inlet 2, and publicly known and publicly available configurations can be adopted without special restrictions.

[0033] The positions of the movable formwork 1 may be referred to as the top portion 11, shoulder portion 12, or side wall portion 13, but it is not necessary for the formwork to be divided into different shapes for each portion; these terms are merely used to indicate the approximate position within the formwork.

[0034] The top portion 11 is the uppermost part of the movable formwork 1. The shoulder portions 12 are provided at both ends of the top portion 11 and are located in the middle of the movable formwork 1. The side wall portion 13 is provided at the lower end of the shoulder portion 12 and is located at the lowest part of the movable formwork 1. The terms top portion 11, shoulder portion 12, and side wall portion 13 are used not only to indicate the position in the formwork, but also to indicate the position of the space to which concrete will be poured (the space between the movable formwork 1 and the ground G) corresponding to these positions.

[0035] As shown in Figure 1, the pressure inlet 2 is provided at the lower part of the side wall portion 13 of the movable formwork 1. The present invention provides a configuration in which concrete is injected into the entire space to be poured, from the side wall portion 13 to the top portion 11, without moving the nozzle of the pumping pipe, solely from the pressure inlet 2 provided at the lower part. The lower part of the side wall portion 13 of the movable formwork 1 described above is preferably located within 500 mm from the lower end of the formwork. In other words, the press inlet 2 is preferably located within 500 mm from the lower end of the side wall portion 13 of the movable formwork 1.

[0036] Preferably, the pressure inlets 2 are located at the lower part of the side wall portion 13 of the movable formwork 1, with two provided on each of the left and right side wall portions 13, for a total of four pressure inlets 2 on both sides. In this example, we will describe a configuration in which a total of four pressure inlets 2 are provided on both the left and right sides. However, the present invention does not exclude a configuration in which one pressure inlet 2 is provided on each of the left and right side walls, for a total of two pressure inlets 2 on both sides. Furthermore, in explaining this invention, when viewing from the wrap side towards the toe side, the right-hand side will be referred to as the "right side" and the left-hand side as the "left side."

[0037] Furthermore, of the two pressure inlets provided at the lower part of each of the left and right side wall portions 13, it is preferable that one is a lap-side pressure inlet 21 located near the lap-side end, and the other is a central pressure inlet 22 located in the middle between the lap-side and the toe-side.

[0038] To clarify the location where the pressure inlet 2 is provided, we will now explain the terminology used to describe the position when viewed from the side on the movable formwork 1. Figure 2 is a schematic diagram of the movable formwork 1 viewed from the side, with the right side being the lap side and the left side being the toe side. As shown in Figure 2, the side of the movable formwork 1 is divided horizontally into three equal sections: the lap side, the center, and the toe side, from right to left. These represent the positions where the press inlet 2 will be installed. Furthermore, the area near the wrap end refers to the right side (the end of the wrap) when the width of the wrap side is further divided into two. Similarly, the area near the toe end refers to the left side (the end of the toe) when the width of the toe side is further divided into two.

[0039] The concrete used in this invention is self-compacting concrete. Self-compacting concrete refers to a type of high-flow concrete that does not require compaction during placement. Conversely, high-flow concrete that requires compaction during placement is called medium-flow concrete.

[0040] While medium-flow concrete expands (flows) into space when vibrated with a vibrator or the like after placement, self-compacting concrete expands (flows) into space solely by its own weight without the need for vibration. In other words, in this invention, by using self-compacting concrete, compaction work becomes unnecessary during the construction process (placement process) of the lining concrete.

[0041] Next, the procedure and process for pouring concrete into the movable formwork 1 will be explained according to Figures 3 to 5. Figure 3 is a schematic diagram showing how concrete is injected into the interior of the movable formwork 1 (the space between the movable formwork 1 and the ground G, where the lining concrete is constructed) from the injection inlets 2 (21, 22) located at the bottom, and how the concrete is poured in the order of the side wall portion 13, the shoulder portion 12, and the top portion 11 without moving the nozzle of the pumping pipe. Figure 3(a) is a schematic diagram showing how concrete is filled into the side wall, Figure 3(b) shows how concrete is filled into the shoulder, and Figure 3(c) shows the process of concrete being filled into the top.

[0042] As described above, in the method for constructing lining concrete according to the present invention, it is preferable that four injection inlets 2 are provided at the bottom of the movable formwork 1, and that concrete is injected from there. The concrete pumping pipe 3 is installed from the lap side to the toe side, and the switching device 4 allows the direction of concrete pumping to be switched to the right, left, or both sides. It should be noted that the present invention does not require the presence of the switching device 4. Furthermore, pumps may be placed in each of the left and right pressure pipes 3.

[0043] Figure 4 is a schematic diagram illustrating the process of injecting concrete C from the side wall 13 into the shoulder 12. Figure 4(a) shows the positional relationship between the pumping pipe 3, the switching device 4, and the injection inlet 2, and the flow of concrete C indicated by arrows. Figure 4(b) shows the movable formwork 1 to which the pumping pipe 3, etc., are connected, and the flow of concrete C inside it, indicated by arrows.

[0044] Concrete is injected from the side wall portion 13 into the shoulder portion 12 using four injection ports 2 (21R, 22R, 21L, 22L). First, concrete is injected into either of the two injection ports 2 on the left or right side, and poured to a predetermined height. Then, the direction of concrete injection is switched to the other two injection ports 2, and poured to a predetermined height, thereby injecting the concrete alternately from left to right.

[0045] Specifically, concrete is first pumped to the right-side lap inlet 21R and the central inlet 22R, and poured to a predetermined height. Next, the pumping direction is switched to the left using the switching device 4, and concrete is pumped to the left-side lap inlet 21L and the central inlet 22L, and poured to a predetermined height. The order of pouring is irrelevant, whether left or right. This process is repeated alternately on the left and right sides, and concrete is injected from the side wall 13 into the shoulder 12. The pouring height per batch can be set to, for example, about 50 cm. However, the method according to the present invention is not limited to this alternating left-right injection method, and does not exclude means of simultaneously pumping concrete to both sides (right and left) injection ports 2, that is, means of simultaneously pumping concrete from all four injection ports 2.

[0046] Next, concrete is injected into the top surface 11. The injection of concrete into the top surface 11 is also carried out using the same four injection ports 2 (21R, 22R, 21L, 22L) as the injection of concrete from the side wall 13 to the shoulder 12, up to a certain range. A method of pouring alternately from left to right may also be employed. After concrete has been injected and filled to a certain extent at the top surface 11, the concrete injection method is switched to another method.

[0047] Figure 5 is a schematic diagram illustrating the process of injecting concrete into a portion of the top surface 11. Figure 5(a) shows the positional relationship between the pumping pipe 3, the switching device 4, and the injection inlet 2, and the flow of concrete C indicated by arrows. Figure 5(b) shows the movable formwork 1 to which the pumping pipe 3, etc., are connected, and the flow of concrete C inside it, indicated by arrows.

[0048] After concrete has been injected and filled to a certain extent at the top surface 11, when it is necessary to inject and fill the remaining area with concrete, the central injection ports (22R and 22L) on both the left and right side walls 13 are closed, and the lap-side injection port (21R or 21L) on either the left or right side wall 13 is also closed, and the concrete is pumped through the remaining single injection port (21R or 21L). Here, this injection method will be referred to as "single-sided injection." Switching to this "single-sided injection" state can accelerate the filling of concrete into the toe end.

[0049] The timing for switching to this single-sided pouring is preferably after the concrete C has reached all formwork surfaces 14. By minimizing the range of this single-sided pouring, i.e., the time required for pouring, it is possible to prevent the concrete C from hardening and blocking the inside of the pumping pipe 3 connected to the closed pressure inlet.

[0050] Figure 6 is a schematic diagram illustrating the timing of the transition to single-sided pouring. Figure 6(a) shows a state where concrete C has not yet reached a portion of the formwork surface 14 at the top, and Figure 6(b) shows a state where concrete C has reached all of the formwork surfaces 14 from the side walls to the top. In other words, the timing of the transition to single-sided pouring is after the state shown in Figure 6(b) is reached. A means for recognizing that concrete C has reached all formwork surfaces 14 of the movable formwork 1 will be described later.

[0051] Next, we will explain the various sensors installed in the mobile formwork 1 and the means of using these sensors to check the status of concrete injection and filling into the formwork. This invention involves installing a filling detection sensor 7 and a pressure sensor 8 on a movable formwork 1 or the like, and using these to check the concrete injection and filling status.

[0052] The filling detection sensor 7 is a sensor that can sense (detect) the arrival of concrete and notify the user of this. There are no specific limitations on the configuration of the filling detection sensor, and any publicly known or publicly available configuration can be adopted without special restrictions. For example, the sensor part is a vibration device that detects vibrations, and when air, water, or concrete comes into contact with this device, the peak output of the vibration device changes. By detecting this change, it is possible to detect that concrete C has reached the location where the filling detection sensor 71 is installed. Other examples include configurations that detect the arrival of concrete by pressure or temperature.

[0053] Examples of the form of the filling detection sensor 7 include a point-shaped filling detection sensor 71 and a sheet-shaped filling detection sensor 72. The point-shaped filling detection sensors 71 detect the localized arrival of concrete, and by installing multiple sensors at various locations on the movable formwork 1, it is possible to determine which areas have been filled with concrete and which have not. Specifically, multiple point-shaped filling detection sensors 71 are connected to a computer or measuring instrument, and the detected information is transmitted to the computer or other device. Although the term "point-like" is used, the shape is not limited to round; it may be square or other shapes.

[0054] The sheet-shaped filling detection sensor 72 is long and thin, allowing it to detect the arrival of concrete over a relatively wide area. This sheet-shaped filling detection sensor 72 is also connected to a computer or measuring instrument, and the detected information is transmitted to the computer or other device. For example, by attaching this sheet-shaped filling detection sensor 72 to the ground G located above or to the side of the movable formwork 1, it is possible to detect when concrete has reached the surface of the ground G.

[0055] The pressure sensor 8 is a sensor installed on the movable formwork 1 that can measure the pressure acting on the formwork, and is also called a pressure gauge. While the aforementioned filling detection sensor 7 is a sensor that confirms the arrival of concrete at its installation location, this pressure sensor 8 is configured to determine the degree of concrete filling by measuring the pressure acting on the formwork at the installation location. Since the pressure value corresponding to a predetermined lining thickness can be calculated in advance, it can be determined that the concrete filling is sufficient when this pressure value is reached. There are no limitations on the specific configuration of the pressure sensor, and publicly known and publicly available configurations can be adopted without special restrictions. This pressure sensor 8 is also connected to a computer or measuring instrument, and is configured to transmit the information (pressure value) detected by the measurement to the computer or other device.

[0056] The locations for installing the filling detection sensor 7 and the pressure sensor 8 will be explained in accordance with Figures 7 and 8. Figure 7 is a schematic diagram showing the location where the filling detection sensor 7 will be installed. As shown in Figure 7, the dot-shaped filling detection sensors 71 are preferably installed horizontally in parallel near the toe end, near the lap end, and in the center between them. Furthermore, it is preferable that these three horizontally parallel-installed filling detection sensors form a set (shown by a dashed line in Figure 7), and that multiple sets of these sensors are installed in parallel at equal intervals from the side wall 13 to the top 11. By installing them in this manner, the horizontal position (placement height) where the concrete C has been filled can be accurately determined. In particular, the filling sensing sensors 71, which are installed near the toe end and the wrap end, are preferably positioned closer to the toe end and the wrap end in order to detect filling at the ends, and are preferably installed in a position that contacts the ends or is very close to them.

[0057] Furthermore, as shown in Figure 7, it is preferable that the sheet-shaped filling sensing sensor 72 be installed on the top of the ground G located above the top of the top surface 11 of the movable formwork 1, in the range from near the toe end to near the lap end. By installing it in this way, it is possible to confirm that the concrete C has reached the top of the void (the space to which concrete is to be poured) between the formwork and the ground.

[0058] Figure 8 is a schematic diagram showing the location where the pressure sensor 8 will be installed. As shown in Figure 8, it is preferable that the pressure sensors 8 are installed near the toe end, the lap end, and the center between them at the lower part of the left and right side walls 13, as well as near the toe end, the lap end, and the center between them at the top of the top surface 11. This allows the filling status of the concrete C to be determined by the pressure value detected by the pressure sensors 8.

[0059] In particular, the pressure sensors 8 installed near the toe end and the wrap end are preferably positioned as close as possible to the toe end and the wrap end in order to grasp the pressure at the ends, and are preferably installed in a position that contacts the ends or is very close to them.

[0060] In the present invention, in order to construct the lining concrete as planned, it is preferable to confirm by the filling sensing sensor 7 that concrete has reached the entire area to be poured, and by the pressure sensor 8 that the standard pressure has been applied to the formwork and that the concrete filling is sufficient.

[0061] As explained in Figure 7, the dot-shaped filling detection sensors 71 are installed at equal intervals from the side wall to the top surface. Therefore, when all installed filling detection sensors 71 detect the arrival of concrete C, it is possible to confirm that concrete C has reached all formwork surfaces 14. By confirming that concrete has reached all formwork surfaces 14, the timing for transitioning to the aforementioned single-sided pouring method can be determined. Furthermore, since the pouring height can be determined in real time by the information obtained from the point-shaped filling sensing sensors 71 installed at equal intervals from the side wall to the top, the difference in the pouring height (synonymous with pouring height) of the concrete relative to the left and right formwork (for example, the side wall portion 13 or shoulder portion 12 of the movable formwork 1) can be managed to a predetermined height. For example, one possible method is to control the difference in launch height between the left and right sides to keep it within 500 mm.

[0062] Furthermore, to reiterate, in addition to the point-shaped filling detection sensor 71, by installing a sheet-shaped filling detection sensor 72 at the top of the ground, in an area extending from near the toe end to near the lap end, it is possible to confirm that the concrete C has reached the uppermost part of the void (the space to which concrete is to be poured) between the formwork 1 and the ground G.

[0063] Furthermore, the filling of concrete C can be confirmed by all of the pressure sensors 8 indicating a pressure value corresponding to a predetermined lining thickness obtained in advance through calculation. Furthermore, when the pressure sensor 8 installed near the toe end reaches 1.5 times the pressure value corresponding to the predetermined lining thickness, it can be confirmed that the concrete C is sufficiently filled. By confirming these points, it can be determined that the necessary lining concrete has been constructed, and thus the concrete pouring can be considered complete. [Explanation of Symbols]

[0064] 1. Mobile formwork 11 Top surface 12 Shoulder 13 Side wall section 14 Formwork surface 2 Pressurized Inlet 21R Lap side pressure inlet (located on the right side wall) 21L Wrap-side pressure inlet (located on the left side wall) 22R Central pressure inlet (located on the right side wall) 22L Central pressure inlet (located on the left side wall) 3. Pressure pipe 4. Switching device 5 Gantries 6 rails 7. Filling detection sensor 71-point filling detection sensor 72 Sheet-type filling detection sensor 8. Pressure sensor C Concrete G. Ground (ground surface)

Claims

1. In a method for constructing the lining concrete of a mountain tunnel by injecting concrete into a movable formwork consisting of side walls, shoulders, and top sections, The concrete is self-compacting concrete, The concrete is injected into the entire area from the side wall to the top surface, solely through an injection port provided at the lower part of the side wall. The aforementioned press inlets are provided at two locations on the lower part of each of the left and right side walls, one near the end of the wrap side and the other in the central part between the wrap side and the toe side. After confirming that the concrete injected through the injection port has reached all formwork surfaces, A method for constructing lining concrete, characterized in that the central pressure inlet in both the left and right side walls is closed, and the lap-side pressure inlet in either the left or right side wall is closed, and the concrete is injected through the remaining single pressure inlet to fill the movable formwork with the concrete.

2. The configuration allows for monitoring the concrete's arrival at the formwork surface using a filling detection sensor that senses the concrete's arrival. The filling detection sensors are installed horizontally in parallel near the toe end, near the wrap end, and in the center between these two points. These three horizontally parallel-installed filling detection sensors constitute a set, Multiple sets of the aforementioned filling detection sensors are installed in parallel at equal intervals from the side wall to the top surface, and they determine the horizontal position where concrete filling is complete. The method for constructing lining concrete according to claim 1, characterized in that when all of the installed filling sensing sensors sense the arrival of the concrete, it is confirmed that the concrete has reached all of the formwork surfaces.

3. The method for constructing lining concrete according to claim 2, characterized in that the difference in the height of the concrete poured on the left and right sides is controlled to 500 mm or less based on information obtained from filling sensing sensors installed at equal intervals from the side wall to the top surface.

4. In order to understand the status of concrete filling in each part of the movable formwork, a pressure sensor is installed to detect the pressure acting on the formwork. The pressure sensors are installed near the toe end, near the lap end, and in the center between them at the lower part of the left and right side walls, as well as near the toe end, near the lap end, and in the center between them at the top of the top surface. The method for constructing lining concrete according to claim 3, characterized in that the filling status of the concrete is determined by the pressure value detected by the pressure sensor.

5. The filling detection sensor is in the shape of a sheet. The aforementioned sheet-like filling sensing sensor is installed on the top of the ground located above the top of the top end of the movable formwork, in a configuration that extends from near the end on the toe side to near the end on the lap side. A sheet-shaped filling detection sensor detects when concrete is reached. The method for constructing concrete lining according to claim 4, characterized in that all pressure sensors indicate a pressure value corresponding to a predetermined lining thickness, and the concrete injection is terminated when the pressure sensor installed near the toe end reaches 1.5 times the pressure value indicating the predetermined lining thickness.

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