JP3288633B2 - Segment sealing material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a segment sealing material which is a waterproof material attached to a segment joint of a shield tunnel used for a subway, a common conduit for electric wires, a rainwater storage tank, a water supply and a sewage system, and the like.

[0002]

2. Description of the Related Art Conventional sealing materials used for shield tunnel segments are conventionally made of sponge rubber, butyl rubber,
Vulcanized rubber and water-swelled rubber are used. In particular, the water-swelling rubber has been improved in reliability in recent years and has become a main material of the segment seal material since the water stoppage rate is greatly improved as compared with the conventional material.

Conventionally, segments for shield tunnels are made of reinforced concrete, cast iron, steel, etc.
The cross-sectional shape of the seal groove is almost trapezoidal in most cases, and the sealing material used for this is basically a rectangular (rectangular) cross-sectional shape.

[0004] In recent years, the connection method,
Various proposals have been made for improving the durability and economical manufacturing method, and a new segment (hereinafter, referred to as an NM segment) having a seal groove having a semicircular cross section has been put to practical use.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a segment seal material suitable for an NM segment having a seal groove having a semicircular cross-sectional shape, which has good assembling workability, has excellent water stopping performance, and is economically advantageous. It is intended to provide a simple segment sealing material.

As for the sealant for the NM segment, a composite of a water-expandable rubber and a non-expandable rubber has already been proposed in Japanese Patent Application Laid-Open No. 9-195592. However, the proposed product has a complicated shape and configuration, is difficult to manufacture easily, and is economically limited in its widespread use.

[0007]

As a result of various studies on the above-mentioned problems, the present inventors have found that a segment for an NM segment which has a good assembling workability, has excellent water stopping properties, is easy to manufacture and is inexpensive. We came to find a sealing material.

That is, a band-shaped segment sealing material which is made of a water-expandable rubber having a JIS hardness of 55 to 70 and a water expansion ratio of 2 to 4 times, and has a circular section having a substantially fan-shaped notch. , And a segment sealing material comprising a rectangular portion connected in a substantially diametrical direction.

The rubber used for the water-swelling rubber used for the segment sealing material of the present invention is not particularly limited as long as it is a rubber generally used industrially, but it is generally a synthetic rubber of chloroprene rubber, ethylene-propylene rubber or It is desirable to use natural rubber, especially chloroprene rubber or natural rubber. Further, it is desirable that 50% by weight or more of the rubber component is chloroprene rubber or natural rubber. The water-swelling rubber used in the present invention is obtained by mixing a water-absorbing resin such as a modified polyacrylic acid-based resin as a water-absorbing material with these rubbers, or by adding a water-absorbing urethane component to these rubbers by IPN (Inter Pen Pen).
It may be any of those that have been converted to an e.g.

The water-swellable rubber used in the present invention has a hardness of JI.
It has an S hardness (hereinafter referred to as hardness) of 55 to 70, preferably 58 to 68, and it is important that the hardness is higher than that of a conventionally used general water-expandable rubber. If the hardness is less than 55, when incorporating the NM segment,
It is a serious disadvantage that the sealing material cannot withstand the insertion and friction of the segments, causing displacement and turning up, and significantly reducing the water stoppage. If the hardness exceeds 70, the rising of the sealing material, particularly at the corners, when mounting the seal material on the segments becomes large, and the displacement and turning-up at the time of inserting the segments occur. That is, by setting the hardness of the water-expandable rubber in the range of 55 to 70, the slipperiness when the NM segment is incorporated is improved, and the workability is improved.

The water expansion ratio of the sealing material is 2 to 2 in volume ratio.
It is about four times, preferably about three times, and can be adjusted by controlling the amount of the water-absorbing resin, the vulcanization density of the rubber, and the like. If it is less than twice, the water stopping performance due to water expansion will not be sufficiently exhibited, but by suppressing the water expansion ratio in this way, the water expansion stability (shape stability, expansion pressure retention, etc.) will be excellent, Reliability for long-term durability is further improved.

As shown in FIG. 1, the sectional shape of the segment sealing material of the present invention needs to have a circular shape having a substantially fan-shaped cutout portion and a rectangular portion connected substantially in the diameter direction. The cross-sectional shape of the segment sealing material of the present invention and the size of each part of the cross-sectional shape can be designed in a shape corresponding to the groove shape of the NM segment in which it is used. For example, the cross-sectional shape as shown in FIG. For example, for a commonly used NM segment whose groove shape is a semicircle of about 8 mmφ, 8 to 9
A segment sealing material having a circular shape of mmφ, a thickness of 2 to 4 mm, and a length, that is, a cross-sectional shape of 2 to 4 mm on a side of a rectangular portion located substantially in the diameter direction of the circular shape can be preferably used. Further, within a range that does not impair the object of the present invention, the circle does not necessarily have to be a perfect circle, and may be an ellipse or the like close to a circle,
The rectangle does not necessarily have to be an exact rectangle, but may be a trapezoid or the like. The circular portion is provided in the NM segment groove portion shown in FIG. 2, and the rectangular portion contributes to the alignment at the time of mounting the segment sealing material and to the improvement of the water stoppage by crimping the flat joint portion. If the length of the rectangular portion becomes longer, it protrudes from the joint portion when the water expands, so that usually 4 mm or less is sufficient.

The notch in the cross section of the segment sealing material of the present invention is important for preventing displacement, turning-up, and corner portion floating when assembling the segment, and reducing the necessary bolt fastening force. Also, since the compression stress is easily maintained within a certain range, the water stopping property is ensured. As a result, the segment sealing material of the present invention exhibits extremely excellent effects in all of the above-mentioned required characteristics as compared with the products having a circular cross section disclosed in the above-mentioned JP-A-9-195692. The size of the substantially fan-shaped notch can be changed depending on the shape of the segment groove, the size of the sealing material, and the hardness within a predetermined range (for example, FIG. 3). It is preferably 20 to 9/20, more preferably 1/5 to 2/5, and a size of about 1/4 is most effective. Further, the opening position of the cutout portion is preferably in the direction of a rectangular portion where one side of the sector is connected to a substantially circular shape as shown in FIG. Also, the notch does not necessarily need to include the center of the circle.

Further, it is effective to provide a hollow portion having a circular shape (FIG. 4), a semicircular shape (FIG. 5), an elliptical shape (FIG. 6) or the like in the cross-sectional shape without impeding the implementation of the present invention. .

As the method for molding the segment sealing material comprising the water-swellable rubber of the present invention, press molding, continuous extrusion crosslinking / molding, and the like, which are usually used in the rubber industry, can be used. For example, it is formed into a ring shape by press molding, a strip-shaped molded product is obtained by a continuous extrusion crosslinking / molding method such as a UHF vulcanizing equipment (Ultra High Frequency vulcanizing equipment), and both ends are adhered and fused. It can be obtained by connecting by a method such as vulcanization adhesion to make the whole annular.

[0016]

The present invention will be described below by way of examples. Using a base rubber compound as shown in Table 1, by continuous extrusion crosslinking / molding method, it has the hardness and water expansion ratio shown in Table 1, and has a 9 mmφ circular portion and a 4 mm thick rectangular portion in a cross-sectional shape. A molded product was obtained, and its both ends were connected to make the whole annular, thereby producing a segment sealing material. Next, each performance test was performed using a testing machine having an NM segment groove (circular portion: 8 mmφ). In Table 1, CR and NR of the base rubber represent chloroprene rubber and natural rubber, respectively.

The conceptual diagram of the tester and the test method are as follows. 1) Slip property test: The slippage and the degree of turning of the sealing material were visually determined by the method shown in the schematic diagram of FIG. 2) Followability of corner portion: A sealing material was attached to a corner portion as shown in the schematic diagram of FIG. 8, and the floating property was visually determined. 3) Water resistance test: Using a test device as shown in FIG.
Use a 4mm thick spacer, tighten,
The pressure was increased, and the presence or absence of water leakage was visually determined.

[0018]

[Table 1]

[0019]

As described above, according to the segment sealing material of the present invention, the following effects can be obtained. (1) By setting the rubber hardness to 55 to 70, when the NM segment sealing material is mounted, there is no lifting of a corner portion, and a so-called curling phenomenon is suppressed, and workability is improved. (2) By keeping the water expansion ratio as low as 2 to 4 times,
Excellent water expansion stability (shape stability, expansion pressure retention, etc.)
Reliability for long-term durability is further improved. (3) The NM has a substantially fan-shaped cutout shape of a circular portion and a cross-sectional shape having a rectangular portion connected to the cutout shape.
When installing in the segment groove, positioning is easy, lifting at corners is prevented, misalignment and turning up during assembly are prevented, and required bolt fastening force is reduced, improving workability . As a result, the water stoppage is greatly improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (1/4 notch) showing an example of a segment sealing material according to the present invention.

FIG. 2 is a sectional view showing an example of an NM segment.

FIG. 3 is a cross-sectional view (2/5 notch) showing an example of the segment sealing material according to the present invention.

FIG. 4 is a sectional view (circular hollow) showing an example of a segment sealing material according to the present invention.

FIG. 5 is a sectional view (semicircular hollow) showing an example of a segment sealing material according to the present invention.

FIG. 6 is a cross-sectional view (an oval hollow) showing an example of a segment sealing material according to the present invention.

FIG. 7 is a schematic diagram of a method for testing the slipperiness of a segment seal material in Examples.

FIG. 8 is a schematic diagram of determining the followability of a corner in the embodiment.

FIG. 9 is a schematic diagram (cross-sectional view) of a water resistance test apparatus in an example.

[Explanation of symbols]

 1. Circular cutout 2. Rectangular part 3. Segment sealing material 4. 4. Direction of force Pressure gauge 6. 6. Water supply port spacer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-195692 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) E21D 11/38

Claims (3)

(57) [Claims] 1. A band-shaped segment sealing material, comprising:
It is made of a water-expandable rubber having an IS hardness of 55 to 70 and a water expansion ratio of 2 to 4 times, and has a circular section having a substantially fan-shaped cutout section and a rectangular section connected in a substantially diametric direction. Characteristic segment sealing material. 2. The segment sealing material according to claim 1, wherein 50% by weight or more of the rubber component of the water-swelling rubber is chloroprene rubber or natural rubber. 3. The segment sealing material according to claim 1, wherein the segment sealing material is manufactured by an extrusion crosslinking molding method.