JP7179436B2 - Tarpaulin - Google Patents

Description

The present invention relates to waterproof sheets.

After covering the inner wall surface of the tunnel formed by excavating the ground with a waterproof sheet, concrete is placed between the outer peripheral surface of the concrete placing formwork and the inner wall surface of the tunnel. BACKGROUND ART A lining concrete placing device for lining a wall surface is known (see Patent Document 1).
The concrete placing formwork is provided with a plurality of pouring openings spaced apart in the longitudinal and circumferential directions of the tunnel. Concrete is placed from the opening of the concrete placing form, and then concrete is poured from the lower opening of the other half of the concrete placing formwork in the circumferential direction. Concrete is placed between the outer peripheral surface of the formwork and the inner wall surface of the tunnel.
In such a lining concrete placing machine, a worker visually checks the position of the placed concrete in order to ensure that the concrete is filled between the outer peripheral surface of the concrete placing formwork and the inner wall surface of the tunnel without gaps. The operator controls the amount of concrete to be placed based on the position and height of the placed concrete along the longitudinal direction of the tunnel, while confirming the amount of concrete by the operator.
On the other hand, an elongated level sensor for detecting the position and height of placed concrete has been provided (see Patent Document 2).

JP-A-7-91192 Japanese Patent No. 5748499

Therefore, by attaching such a level sensor to the inner surface of the waterproof sheet so as to extend along the circumferential direction and the longitudinal direction of the tunnel before placing the concrete, it was possible to place the concrete using the level sensor. It is conceivable to detect the position and height along the longitudinal direction of the concrete tunnel, thereby omitting the work of visual confirmation by the operator.
However, when attaching the level sensor to the inner surface of the waterproof sheet, since the inner wall surface of the tunnel exhibits a curved surface with the top of the tunnel as the apex, workers must It is necessary to perform the level sensor mounting work while taking an unreasonable posture on the scaffold, which makes the work complicated.
Moreover, when constructing a tunnel, if the length of the tunnel is several kilometers or several tens of kilometers, it is necessary to carry out the work of attaching such a level sensor to the inner surface of the waterproof sheet hundreds of times.
Furthermore, there are cases in which the mounting strength of the level sensor is insufficient due to inadequate mounting work of the level sensor, and there is concern that the position of the level sensor may shift when concrete is placed, resulting in a decrease in detection accuracy of the level sensor.
The present invention has been made with a focus on the above-mentioned waterproof sheet, and its object is to provide a waterproof sheet that is advantageous in preventing displacement of the level sensor, improving tunnel construction efficiency, and shortening the construction period. That's what it is.

In order to achieve the above object, the present invention provides a waterproof sheet attached to the inner wall surface of a tunnel so as to cover the inner wall surface, wherein the waterproof sheet has a detection amount according to the length of contact with concrete. an elongated level sensor whose longitudinal direction changes along the circumferential direction of the tunnel, and the level sensor has an elongated shape formed by covering a pair of electrode wires with an insulating material. The detected amount is the capacitance generated between the pair of electrode wires in accordance with the relative permittivity of the concrete by contacting the concrete, and the waterproof sheet extends along the length of the tunnel. A plurality of waterproof sheet divisions having a length and a width along the circumferential direction of the tunnel are arranged in the length direction of the tunnel with the length direction of the waterproof sheet divisions extending in the length direction of the tunnel. A pair of waterproof sheet divided bodies adjacent to each other in the length direction of the tunnel have the longitudinal ends of the waterproof sheet extending in the width direction at the ends in the length direction of the pair of waterproof sheet divided bodies. Each of the pair of waterproof sheet divisions is bent radially inward of the inner wall surface of the tunnel and overlapped, and a portion of the overlapped waterproof sheet longitudinal end near the inner wall surface is extended over the entire width direction of the pair of waterproof sheet divisions. The level sensor is connected by forming a welded linear welding region, and the level sensor is connected to the superimposed waterproof sheet divided body of one of the pair of waterproof sheet divided bodies adjacent in the length direction of the tunnel. The pair of the pair of Penetrating from the waterproof sheet length direction end of one of the waterproof sheet divided bodies to the waterproof sheet length direction end of the other waterproof sheet divided body of the pair of waterproof sheet divided bodies It is characterized in that it is attached using any of thread, wire, or needles of a stapler .
Further, the present invention is characterized in that the inner wall surface of the tunnel is the inner surface of an excavated natural ground or the inner surface of a primary lining formed by spraying concrete on the inner surface of the natural ground.

According to the present invention, by attaching the waterproof sheet to which the level sensor is attached to the inner wall surface of the tunnel, the level sensor is installed on the inner wall surface of the tunnel at the same time. can do.
In addition, it is possible to grasp the position or height of the concrete placed in the tunnel from the amount detected by the level sensor. It is possible to reliably and efficiently fill the gap between the concrete and the inner wall surface of the tunnel.
In addition, since the level sensor is pre-attached to the waterproof sheet before the waterproof sheet is attached to the inner wall surface, there is no deterioration in the mounting strength of the level sensor due to inadequate mounting work, and the position of the level sensor does not shift during placement. It is advantageous in accurately detecting the position of placed concrete using a level sensor.
Therefore, it is advantageous in terms of increasing tunnel construction efficiency and shortening the construction period.
Moreover, according to the present invention, it is advantageous in reliably detecting the longitudinal position and height of the placed concrete tunnel.
Moreover, according to the present invention, it is advantageous in reliably attaching the level sensor to the inner surface of the waterproof sheet, and in improving the efficiency of the level sensor attaching work.
Moreover, according to the present invention, it is advantageous in securely attaching the level sensor to the waterproof sheet.
Moreover, according to the present invention, it is more advantageous in suppressing positional displacement of the level sensor due to placed concrete.
Moreover, according to the present invention, the level sensor is mounted at a location that does not affect water leakage, which is advantageous in terms of improving the efficiency of the level sensor mounting work.
Further, according to the present invention, it is advantageous in achieving the above effects whether the inner wall surface of the tunnel to which the waterproof sheet is attached is the inner surface of the primary lining or the inner surface of the excavated natural ground.
Further, according to the present invention, the capacitance of the level sensor can be detected by a simple detection circuit, which is advantageous in easily determining the position and height of the placed concrete tunnel in the longitudinal direction.

1 is a front cross-sectional view of a tunnel to which the waterproof sheet of the first embodiment is applied; FIG. FIG. 4 is an explanatory diagram showing a state in which the waterproof sheet of the first embodiment is laid on the inner wall surface of a tunnel; 1 is an exploded view of a waterproof sheet according to a first embodiment; FIG. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; (A) is a view of the waterproof sheet viewed from the inside, and (B) is a cross-sectional view taken along line BB of (A). It is a perspective view of a level sensor. FIG. 4 is an explanatory diagram showing the configuration of a level sensor and a detection circuit; FIG. 8B is a view of the inner surface of the waterproof sheet portion of the second embodiment, and FIG. FIG. 4 is a cross-sectional view showing a state in which the level sensor is attached inside the waterproof sheet; FIG. 11 is an explanatory diagram of a case where a level sensor is attached to a waterproof sheet according to a third embodiment, (A) is a cross-sectional view showing the state before joining the waterproof sheet divisions, and (B) is a diagram showing the state after the waterproof sheet divisions are joined. (C) is a cross-sectional view showing a state in which the end portion is folded over the waterproof sheet divided body, and (D) is a plan view of (C).

(First embodiment)
Embodiments of the present invention will now be described with reference to the drawings.
As shown in FIG. 1, the natural ground 18 is excavated, the inner surface of which is sprayed with concrete to construct the primary lining 20, the inner surface of the primary lining 20 is covered with the waterproof sheet 14, and the inside of the waterproof sheet 14 is covered with the waterproof sheet 14. The concrete placing formwork 16 is arranged, and the concrete 22 is placed between the outer peripheral surface (formwork surface) of the concrete placing formwork 16 and the waterproof sheet 14, thereby performing the secondary lining of the tunnel 10. be.
Reference numeral 13 denotes the floor slab of the tunnel 10. As shown in FIG.
In the present invention, the inner wall surface 12 of the tunnel 10 is the inner surface of the excavated natural ground 18 or the inner surface of the primary lining 20 constructed by spraying concrete on the inner surface of the natural ground 18 .
In the present embodiment, the case where the inner wall surface 12 of the tunnel 10 is composed of the inner surface of the primary lining 20 will be described.

The waterproof sheet 14 prevents underground water from entering the tunnel 10, and has a rectangular shape having a width and a length larger than the width.
The waterproof sheet 14 is attached so as to cover the inner wall surface 12 with its longitudinal direction along the longitudinal direction of the tunnel 10 and its width direction along the circumferential direction of the tunnel 10 .
The waterproof sheet 14 is attached, for example, by welding the parts of the waterproof sheet 14 to the heads of anchors or bolts (not shown) previously attached to the inner wall surface 12 of the tunnel 10 .

As shown in FIGS. 2, 3, 4 and 5, an elongated level sensor 24 is attached to the surface 1402 of the waterproof sheet 14 opposite the inner wall surface 12 .
The level sensor 24 may be any sensor that changes its detection amount according to the length of contact with the placed concrete 22, and various conventionally known sensors can be used.
In the present invention, the expression that the level sensor 24 comes into contact with the concrete 22 means that the level sensor 24 comes into direct contact with the concrete 22 as well as the case that the level sensor 24 comes into contact with the concrete 22 via another member. It shall include the case of approaching the concrete 22 through.
In the present embodiment, a case in which a level sensor 24 whose capacitance changes according to the length of contact with the concrete 22 is used will be described.
As shown in FIG. 6, the level sensor 24 includes a pair of electrode wires 26 and an insulating material 28 covering the pair of electrode wires 26, and is elongated.
The level sensor 24 changes the electrostatic capacitance generated between the pair of electrode wires 26 according to the dielectric constant of the concrete 22 when it comes into contact with the concrete 22, and is connected to the level sensor 24 as described later. Based on the voltage detected by the detection circuit 30 (see FIG. 7), the position and height of the placed concrete 22 in the longitudinal direction of the tunnel 10 are obtained.
In this embodiment, the insulating material 28 (level sensor 24) has a strip-like shape having a width in the direction in which the electrode wires 26 are arranged, a thickness smaller than the width, and a length larger than the width. .
The pair of electrode wires 26 extend in parallel with each other at regular intervals in the width direction of the insulating material 28 inside the insulating material 28 .

As shown in FIGS. 3, 4, 5A, and 5B, a plurality of level sensors 24 are provided, and their longitudinal directions are attached so as to extend in the longitudinal direction of the tunnel 10 as necessary, Alternatively, it is mounted so as to extend along the circumferential direction of the tunnel 10 , or it is mounted so as to extend along the longitudinal direction and the circumferential direction of the tunnel 10 .
The level sensor 24 is attached to the surface 1402 of the waterproof sheet 14 by welding one surface of the insulating material 28 in the thickness direction to one surface of the waterproof sheet 14, or by bonding with an adhesive. or by being adhered with a double-sided adhesive tape.
As shown in FIG. 2 , the waterproof sheet 14 is attached to the inner wall surface 12 with its longitudinal direction along the longitudinal direction of the tunnel 10 and its width direction along the circumferential direction of the tunnel 10 . , with its longitudinal direction extending along the circumferential direction of the inner wall surface 12 of the tunnel 10, or with its longitudinal direction extending along the length direction of the tunnel 10, or with the tunnel 10 are arranged in a state of being extended along the longitudinal direction and the circumferential direction of the

In this embodiment, the level sensor 24 includes first to third level sensors 24A, 24B, 24C.
As shown in FIGS. 2 and 3, the first level sensor 24A and the second level sensor 24B are located on each half of the waterproof sheet 14 in the width direction and are spaced apart in the longitudinal direction of the waterproof sheet 14. Five of them are attached so as to extend in the width direction.
Three third level sensors 24C are attached to the central portion of the waterproof sheet 14 in the width direction so as to extend in the longitudinal direction of the waterproof sheet 14 at intervals in the width direction of the waterproof sheet 14 .
Therefore, by attaching the waterproof sheet 14 to the inner wall surface 12 of the tunnel 10, the first level sensor 24A extends along the circumferential direction of the tunnel 10 from the top of the tunnel 10 to one half of the tunnel 10 in the width direction. are installed at equal intervals along the length of the tunnel 10 .
In addition, the second level sensors 24B extending along the circumferential direction of the form body 38 from the top of the tunnel 10 to the other half of the tunnel 10 in the width direction are arranged at equal intervals in the length direction of the tunnel 10. 5 will be installed.
Also, three third level sensors 24C extending in the longitudinal direction of the tunnel 10 are installed so as to pass through the top of the tunnel 10 and to pass through both sides of the top.
In the central portion of the waterproof sheet 14 in the width direction, where the first level sensor 24A and the second level sensor 24B overlap with the third level sensor 24C, one level sensor 24 is positioned below the other level sensor 24C. 24 is attached to the waterproof sheet 14 in a state of being overlaid and attached. In this case, the length of the layered level sensor 24 is extremely short compared to the total length of the level sensor 24, and the position and height of the placed concrete 22 in the tunnel 10 using the level sensor 24, which will be described later, in the longitudinal direction of the tunnel 10. It has negligible impact on the detection of sparseness.

Next, detection of the position and height of concrete 22 in the longitudinal direction of tunnel 10 using level sensor 24 will be described.
As shown in FIG. 7, a detection circuit 30 is connected to the level sensor 24 .
The detection circuit 30 comprises an input terminal 3002 , a DC power supply 3004 , a fixed resistor 3006 and an output terminal 3008 .
The input terminal 3002 is connected to one end of the pair of electrode wires 26 .
A DC power supply 3004 is connected to the input terminal 3002 and applies a constant DC voltage Vin across the electrode wires 26 .
A fixed resistor 3006 is connected in parallel to one end of the pair of electrode wires 26 , and is proportional to the dielectric constant of the concrete 22 to be placed and the length of the pair of electrode wires 26 in contact with the placed concrete 22 . A charging voltage Et corresponding to a change in capacitance occurring between the electrode wires 26 is taken out.
The output terminal 3008 is connected to both ends of the fixed resistor 3006 .

Since a large number of ions are present in the concrete 22 placed in the concrete placing formwork 16, that is, the fresh concrete 22 (mortar), there is a large amount of ions between and around the pair of electrode wires 26 coated with insulation. When the concrete 22 is interposed, a capacitor C1 is formed using the concrete 22 as an electrolyte and according to its dielectric constant.
This capacitor C1 is connected in parallel along the length of the level sensor 24. As shown in FIG. As the length L of the level sensor 24 contacting the concrete 22 increases, the number of parallel-connected capacitors C1 increases and the capacitance increases.
Here, a capacitor C2 having a capacitance corresponding to the dielectric constant of air is also formed in parallel between the electrode wires 26 exposed to the air. Therefore, the capacitance generated between the pair of electrode lines 26 is the sum of the parallel-connected capacitor C1 and the parallel-connected capacitor C2. This capacitance varies according to the length L of the level sensor 24 in contact with the concrete 22 , ie the longitudinal position and height of the poured concrete 22 in the tunnel 10 .
The capacitance between the electrode wires 26 with the concrete 22 as the electrolyte is about ten times the capacitance with air.

Therefore, a constant DC voltage Vin is applied between the two electrode wires 26 from the input terminal 3002 to charge the two electrode wires 26 , and the voltage between the two electrode wires 26 is measured by the detection circuit 30 .
In this case, in the detection circuit 30, the relationship of the output voltage Vout=Et/(R+2r) is established. However, R is the resistance value of the fixed resistor 3006 and r is the specific resistance of the electrode wire 26 .

The measurement result of the output voltage Vout by the detection circuit 30 is the output voltage Vout proportional to the capacitance generated between the two electrode wires 26 according to the dielectric constant of the concrete 22 and the length L of the level sensor 24 in contact with the concrete 22. becomes a relationship close to a proportional relationship.
A correlation expression indicating the correlation between the output voltage Vout and the length L of the level sensor 24 in contact with the concrete 22 is determined in advance by experiment.
Accordingly, the length L of the level sensor 24 in contact with the concrete 22, that is, the position of the concrete 22 along the length direction of the level sensor 24 can be calculated from the output voltage Vout based on the correlation formula.
For example, the output voltage Vout output from the detection circuit 30 is supplied to a personal computer (not shown), and the personal computer calculates the position and height of the concrete 22 in the longitudinal direction of the tunnel 10 from the output voltage Vout based on the correlation equation. be able to.
Therefore, the capacitance of the level sensor 24 can be detected by a simple detection circuit 30, which is advantageous in easily determining the position and height of the placed concrete 22 in the longitudinal direction of the tunnel 10. FIG.
Then, based on the position and height of the concrete 22 in the longitudinal direction of the tunnel 10, the equipment for placing the concrete 22 can be controlled.
This eliminates the need for a conventional worker to visually check the position and height of the placed concrete 22 in the longitudinal direction of the tunnel 10, and the concrete placement between the outer peripheral surface of the concrete placing formwork 16 and the waterproof sheet 14 is eliminated. 22 can be reliably and efficiently filled without gaps.

According to this embodiment, the elongated level sensor 24 extends along the longitudinal direction or width direction of the waterproof sheet 14 on the surface 1402 of the waterproof sheet 14 located on the side opposite to the inner wall surface 12 . installed as shown.
Therefore, the position and height of the placed concrete 22 in the longitudinal direction of the tunnel 10 can be grasped from the amount detected by the level sensor 24, and the position and height of the placed concrete 22 in the longitudinal direction of the tunnel 10 by a conventional worker can be grasped. It is possible to omit the work of visually checking the height, and to fill the gap between the outer peripheral surface of the concrete placing form 16 and the inner wall surface 12 of the tunnel 10 with the concrete 22 reliably and efficiently.
Moreover, since the level sensor 24 is installed on the inner wall surface 12 of the tunnel 10 at the same time by attaching the waterproof sheet 14 to which the level sensor 24 is attached to the inner wall surface 12 of the tunnel 10, the installation of the level sensor 24 inside the tunnel 10 is troublesome. installation work can be omitted.
In addition, since the level sensor 24 is pre-attached to the waterproof sheet 14 before the waterproof sheet 14 is attached to the inner wall surface 12, there is no reduction in the mounting strength of the level sensor 24 due to inadequate mounting work, and the level sensor can be installed during placement. This is advantageous in accurately detecting the position of the placed concrete 22 using the level sensor 24 without causing any inconvenience such as positional deviation of the level sensor 24 .
Therefore, it is advantageous in improving the construction efficiency of the tunnel 10 and shortening the construction period.

In the present embodiment, the waterproof sheet 14 is attached to the inner wall surface 12 with its longitudinal direction along the longitudinal direction of the tunnel 10 and its width direction along the circumferential direction of the tunnel 10. Five level sensors 24A and five second level sensors 24B are attached to each half of the waterproof sheet 14 in the width direction so as to extend in the width direction of the waterproof sheet 14 at intervals in the longitudinal direction of the waterproof sheet 14. It is
Three third level sensors 24C are attached to the central portion of the waterproof sheet 14 in the width direction so as to extend in the longitudinal direction of the waterproof sheet 14 at intervals in the width direction of the waterproof sheet 14 .
Therefore, using the first to third level sensors 24A to 24C is advantageous in reliably detecting the position and height of the concrete 22 in the longitudinal direction of the tunnel 10. FIG.

In this embodiment, the level sensor 24 is attached to the surface 1402 of the waterproof sheet 14 by welding, adhesive, or double-sided adhesive tape. This is advantageous in ensuring that the level sensor 24 is securely attached, and is advantageous in improving the efficiency of the mounting work of the level sensor 24 .

In this embodiment, the inner wall surface 12 of the tunnel 10 to which the waterproof sheet 14 is attached is the inner surface of the primary lining 20 formed by spraying the concrete 22 onto the inner surface of the ground 18. The inner wall surface 12 of the tunnel 10 to which the sheet 14 is attached may be the inner surface of the excavated natural ground 18, and in such a case, the same effects as those of the above embodiment are exhibited.

(Second embodiment)
Next, a second embodiment will be described with reference to FIGS. 8(A) and 8(B).
In the following embodiments, parts and members that are the same as those in the first embodiment are denoted by the same reference numerals as in the first embodiment, and the description thereof is omitted, and the description is focused on the different parts. do.
The second embodiment differs from the first embodiment in that the level sensor 24 is attached to the surface 1402 of the waterproof sheet 14 via the sheet member 32 .
The sheet member 32 is made of the same material as the waterproof sheet 14 and has a strip shape with a width larger than that of the level sensor 24 .
The level sensor 24 is attached to one surface 3202 of the sheet member 32 in the thickness direction so as to extend along the longitudinal direction of the sheet member 32, and the other surface 3204 of the sheet member 32 in the thickness direction is a waterproof sheet. 14 is attached to surface 1402 .
Attachment of the level sensor 24 to the sheet member 32 and attachment of the sheet member 32 with the level sensor 24 attached to the surface 1402 of the waterproof sheet 14 are performed using welding, adhesive, or double-sided adhesive tape.
According to the second embodiment, in addition to the same effects as those of the first embodiment, the following effects are also achieved.
Attachment of the level sensor 24 to the sheet member 32 is advantageous in terms of easy and reliable attachment since both are smaller than the waterproof sheet 14 .
Moreover, since the width of the sheet member 32 is larger than that of the level sensor 24, the attachment of the sheet member 32 to the waterproof sheet 14 is easier and more reliable than the case of directly attaching the level sensor 24 to the waterproof sheet 14. - 特許庁advantage over
Moreover, since the sheet member 32 is made of the same material as the waterproof sheet 14, the sheet member 32 has good adhesion to the waterproof sheet 14, and the sheet member 32 is securely attached to the waterproof sheet 14. This is advantageous for reliably attaching the level sensor 24 to the waterproof sheet 14 .

The waterproof sheet 14 of the level sensor 24 may be attached before the waterproof sheet 14 is attached to the inner wall surface 12 of the tunnel 10. It may be performed on a flat site, or on a flat floor slab 13 in the tunnel 10, or the like.
Moreover, in the embodiment, the case where the level sensor 24 is attached to the surface 1402 of the waterproof sheet 14 located on the side opposite to the inner wall surface 12 has been described.
However, as described above, the level sensor 24 only needs to change the detection amount according to the length of contact with the placed concrete 22, and various conventionally known sensors can be used. The level sensor 24 coming into contact with the concrete 22 in , includes not only the case where the level sensor 24 comes into direct contact with the concrete 22, but also the case where the level sensor 24 comes into contact through another member, for example, through the waterproof sheet 14. Including when approaching concrete 22 .
Therefore, the location where the level sensor 24 is arranged may be the surface of the waterproof sheet 14 located on the same side as the inner wall surface 12, or the level sensor 24 may be attached inside the waterproof sheet 14 as shown in FIG. good.
In these cases, since the level sensor 24 is protected by the waterproof sheet 14 , it is more advantageous in suppressing the positional displacement of the level sensor 24 due to the placed concrete 22 .

(Third Embodiment)
In the third embodiment, a case where level sensors 24 are attached to joints of adjacent waterproof sheets 14 will be described.
For example, when the length of the tunnel 10 of the concrete placing form 16 is 10.5 m, and the length of the waterproof sheet 14 along the length of the tunnel 10 is about 2 m, , it becomes necessary to join a plurality of waterproof sheets 14 together.
Here, for convenience of explanation, a case will be described in which the waterproof sheet 14 having a length corresponding to the length of the concrete placing formwork 16 is formed by arranging a plurality of waterproof sheet divisions in the width direction and joining them together by welding. do.
The waterproof sheet 14 is composed of a plurality of waterproof sheet divided bodies each having a length along the longitudinal direction of the tunnel 10 and a width along the circumferential direction of the tunnel 10. The waterproof sheet end portions at the ends in the length direction thereof are superimposed on each other, and the ends of the superimposed waterproof sheets are welded over the entire length in the width direction to form a linear welding region.
The level sensor 24, which is attached so as to extend along the circumferential direction of the tunnel 10, is mounted at one of the overlapping waterproof sheet end portions in the longitudinal direction of the waterproof sheet end portion. It is attached outside the welding area.

That is, a plurality of waterproof sheet divisions are joined as follows. In order to simplify and clarify the explanation below, two waterproof sheet divisions 14A and 14B are joined as an example.
As shown in FIGS. 10A and 10B, the ends in the length direction of the adjacent waterproof sheet divisions 14A and 14B are formed into band-like end portions 1410 having a predetermined dimension, for example, about 10 cm in the length direction. These end portions 1410 are overlapped to form a linear welding region 1420 in which the overlapped end portions 1410 are closer to the base portion 1412 and are welded over the entire width direction of the waterproof sheet divisions 14A and 14B. do.
In this example, the welded regions 1420 are two locations spaced apart in the lengthwise direction of the end portions 1410 of the waterproof sheet segments 14A and 14B.
Since the welded regions 1420 are formed in the end portions 1410 of the waterproof sheet divisions 14A and 14B, water leakage from the joints of the waterproof sheet divisions 14A and 14B is prevented.
In the third embodiment, as shown in FIGS. 10(C) and 10(D), the end portion is positioned so that the level sensor 24 faces the outer peripheral surface (formwork surface) of the concrete placing formwork 16 . 1410 is folded over the waterproof sheet division 14B and used.

The level sensor 24 is located at an end portion 1410 of one of the end portions 1410 of the laminated waterproof sheet divisions 14A and 14B, from the welding region 1420 in the length direction of the end portion 1410. are attached so as to extend along the circumferential direction of the tunnel 10.
The level sensor 24 is attached at a location outside the welded region 1420 in the longitudinal direction of the end portion 1410 and at a location that does not affect water leakage. Alternatively, a stapler needle that passes through the end portion 1410 may be used.
The level sensor 24 may be attached before or after forming the welded region 1420 on the end portion 1410, or may be performed at the waterproof sheet 14 factory. Alternatively, it may be performed on a flat site near the tunnel 10, or it may be performed on a flat floor slab 13 inside the tunnel 10, or the like.
Therefore, according to the third embodiment, it is advantageous in improving the efficiency of the mounting work of the level sensor 24.

10 tunnel 12 inner wall surface 14 waterproof sheet 1402 surface 14A, 14B waterproof sheet divided body 1410 end portion 1420 welding region 16 concrete placement formwork 18 ground 20 primary lining 22 concrete 24 level sensor 26 pair of electrode wires 28 insulating material 32 Sheet member 3202 One side 3204 The other side

Claims (2)

A waterproof sheet attached to an inner wall surface of a tunnel so as to cover the inner wall surface,
An elongated level sensor whose detection amount changes according to the length of contact with the concrete is attached to the waterproof sheet so that its longitudinal direction extends along the circumferential direction of the tunnel,
The level sensor has an elongated shape formed by covering a pair of electrode wires with an insulating material,
The detected amount is a capacitance generated between the pair of electrode wires according to the relative permittivity of the concrete by contacting the concrete ,
The waterproof sheet includes a plurality of waterproof sheet divisions each having a length along the length direction of the tunnel and a width along the circumferential direction of the tunnel. arranged along the length of the tunnel by extending to
A pair of waterproof sheet divisions adjacent to each other in the length direction of the tunnel are configured so that the lengthwise ends of the waterproof sheet divisions extending in the width direction are connected to the inside of the tunnel . A linear shape formed by bending and superimposing each waterproof sheet radially inwardly of the wall surface, and welding portions of the longitudinal ends of the superimposed waterproof sheets closer to the inner wall surface to the entire length of the pair of waterproof sheet divisions in the width direction. are connected by forming a welded region of
The level sensor is located inside the welded region of one of the pair of waterproof sheet divided bodies adjacent to each other in the length direction of the tunnel . One of the pair of waterproof sheet divided bodies is disposed radially inward of the wall surface and radially inward of the inner wall surface from the welded region at the longitudinal end of the waterproof sheet . A thread, a wire, or a needle of a stapler is used to penetrate from the longitudinal end of the waterproof sheet to the longitudinal end of the other of the pair of waterproof sheet segments. is worn,
A waterproof sheet characterized by: The inner wall surface of the tunnel is the inner surface of the excavated natural ground, or the inner surface of the primary lining formed by spraying concrete on the inner surface of the natural ground.
The waterproof sheet according to claim 1, characterized by:

Images