JPS6340919B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-stopping material used for assembling shield segments using a shield construction method, and a construction method thereof. Conventional water-stopping materials for assembling shield segments can be roughly classified into (1) non-foamed solid water-stopping materials, and (2) closed-cell solid waterstopping materials. Examples of the water-stopping material (2) include a solid butyl water-stopping material and a solid tar-based waterstopping material, and examples of the waterstopping material (2) include a polyethylene closed-cell foam waterstopping material and a rubber-based closed-cell foam waterstopping material. The reason why these waterproof materials are used is that they have no air permeability and do not allow water to pass through, and it is absolutely necessary that they are fluid and deformable, such as solid butyl waterproof materials. This is because However, when these water-stopping materials are actually constructed on-site, they often have poor water-stopping properties and leak significantly, so there is a demand for water-stopping materials that have excellent water-stopping properties and are easy to construct. In order to solve the conventional problems, the present inventors pursued a water-stopping mechanism of the shield segment, and as a result, discovered a completely different theory from the conventional ones, and were able to solve this problem. As a result of a detailed study of water stoppage when constructed using conventional waterstop materials, we found the following. (1) Particularly sticky solid butyl water-stopping materials may have sand, pebble dust, etc. adhering to them and creating gaps on the surface of the water-stopping material, or pebbles may form between the segments being carried into the tunnel and being assembled. Because there are gaps in the surfaces of the walls, water often leaks from these gaps. (2) When carrying the segment into the tunnel, if the water stop material attached to the segment is a solid water stop material, it will be compressed when it comes into contact with wires, etc. and will be difficult to restore, so a gap will be created in that part after assembly. (3) Due to variations in the dimensional accuracy of the segments, differences in the tightening of bolts during assembly, and especially the curved parts of the shield tunnel, uniform assembly accuracy as designed cannot be achieved. In this case, the parts between the segments where a particularly large stress is applied are compressed, and the other parts are not compressed, resulting in gaps. (4) Move the inserted segment repeatedly to align the bolt holes provided in the segment when assembling the segment. Since the solid water stop material has a high degree of hardness and has a large frictional resistance during this repeated movement, the water stop material may be deformed or peeled off from the segments, creating a gap. (5) During the process of transporting the segments into the tunnel, the solid water-stopping material, which has a large hardness, reduces the volume of the water-stopping material itself due to collisions with surrounding objects and between segments, and cannot escape. The water stop material peels off or tears, creating gaps. Since polyethylene and rubber foams have closed cells, they cannot be handled in the same way as above, and like solid water-stopping materials, they often tear or peel off from the segments when assembling or transporting the segments. (6) Solid butyl water sealing material may undergo thermal deformation during high temperatures in summer and may not be placed in the desired position, and furthermore, the shape may be uneven and gaps may occur in some areas. As described above, it has been found that although conventional water-stopping materials are theoretically capable of completely stopping water, it is difficult to stop water during actual rubbing. In other words, in actual construction of shield segment assembly, if the segment gap is large due to the accuracy of the segments and the accuracy at the time of assembly,
The size is 6mm or more. Therefore, a seal material with a thickness of 4 to 6 mm or more is required, and when this is assembled using a shield shutter, the water stop material inserted between the segments is Since the restoration cannot be followed sufficiently and the gap cannot be eliminated, retightening is required, which complicates the work on site, so there is a desire for something that does not require retightening. The inventors of the present invention conducted research to resolve the drawbacks of these conventional water-stopping materials, and found that the conventional water-stopping materials for shield segments were either non-foamed materials or closed-cell materials. It is preferable to be an open cell material with an open cell ratio of at least 51% or more, and to have a skin layer on at least one surface of the waterproof material. In addition, it has been found that during construction, it is preferable to use the skin layer so that it is approximately perpendicular to the segment surface. The present invention was completed based on this knowledge. Shield segments (hereinafter referred to as segments) and their assembly will be explained based on the drawings. FIG. 1 is a perspective view of a segment, FIG. 2 is a perspective view of a partially assembled segment, FIG. 3 is a cross-sectional view after shield construction, and FIG. 4 is a longitudinal cross-section after shield construction. 1a is the bolt hole that connects the segments, 1b is the side surface of the segment to which the water stop material 2 is pasted, 1c is the connection part that connects the segments 1 to each other, 3 is the backing material, 4 is the secondary lining surface, and 5 is the side surface of the segment. 6 indicates the inside of the tunnel, 7 indicates the shield jack, 8 indicates the shield body, and 9 indicates the tail portion of the shield body. Segment 1 is initially left outdoors and then brought into the mine shaft, but if the sealing material 2 is sticky such as butyl water stop material, pebbles, sand, dust, etc. may adhere to its surface during this time. When assembled as in 1c, pebbles or the like may get caught in the joint surfaces, creating gaps and causing water leakage. If the segments 1 are tied with a rope or the like when being carried in, the rope will come into contact with the solid water stop material 2 bonded to the segment 1 and be compressed, making it difficult to recover, resulting in a gap at that portion after assembly. Segment 1 is usually assembled one ring at a time at the tail of shield body 8, and is attached to shield jack 7.
It is pushed out in the direction of the tunnel 6. In addition, when assembling the segments 1, in order to align the connecting bolt holes 1a of the segments 1, and to repeatedly shift the segments 1 together, if the water stop material 2 is a conventional solid water stop material, there is no escape area for the water stop material 2. If there is no seal, the material may tear, or shearing force acts on the water-stopping material, causing it to separate from the segment, causing water leakage. The present invention is a waterproof material for assembling this segment, which is made of rubber or plastic foam with an open cell ratio of 51% or more and has a skin layer on at least one side. In the present invention, the open cell ratio refers to AST-
1940-62T (1962), calculated from the closed cell ratio and open cell ratio using the following formula. In the present invention, open cell ratio = open cell ratio / closed cell ratio + open cell ratio × 100 If the open cell ratio is lower than 51%, the segments must be repeated to match the connecting bolt holes of the segments when assembling the segments. During the alignment process, there is no place for the water stop material to escape, causing it to tear or peel off from the segments. If the open cell ratio is 51% or more, unlike non-foamed or closed cell materials, the sealing material part will not be completely sealed when backfilling material is injected after segment assembly, and air will escape little by little. Therefore, the backfill material can be completely filled. In general, in shield construction, the accuracy of segment assembly is often 1 mm to 3 mm, but in some cases the gap may be 4 mm or more, and the compression ratio is increased. The thickness of the water-stopping material should be 4 mm, as this can improve waterproof performance.
It is preferable that the thickness is 7 mm or more, and in some cases, 7 mm or more is required. The compression rate referred to here is: Thickness of foam before compression - Thickness of foam after compression / Thickness of foam before compression x 100. The skin layer provided on at least one side of the water stop material of the present invention has the following effects. (1) Water-stopping materials for segment assembly are required to have a water-stopping effect other than that of ordinary water-stopping materials. After the segments are assembled, backing material is injected to prevent ground subsidence. In this case, the pressure of the injected backing material is 2 to 5 kg/cm 2 , or 5 kg/cm ² in some cases.
It can reach ~7Kg/ ^cm2 . Since the water stop material is flexible and has an open cell ratio of 51% or more, it may be deformed by the injection pressure when the backing material is injected, and the backing material may flow out of the segment.
By providing the skin layer, the rigidity of the waterproof material can be increased and the leakage of the backing material can be prevented. (2) Since the open cell ratio is 51% or more, its waterproof performance is inferior to that of closed cell materials, so it is used after being compressed to the target compression ratio.
When assembling segments, gaps that are two to three times the target compression rate may occur due to segment precision and construction precision, but the skin layer has a highly stable waterproof property even under such compression conditions. can be kept. (3) When injecting the backing material into the back side of the segment, air escapes from a portion of the water-stopping material, allowing the backing material to be filled uniformly. By providing a skin layer on the waterproof material, it is possible to increase the open cell ratio for air to escape without reducing the waterproof performance. The rubber or plastic foam with an open cell ratio of 51% or more used in the present invention has a 25% compression hardness in a direction perpendicular to a plane substantially perpendicular to the skin layer of 15 g to 500 g/ ^cm2 , preferably 50 g. ~400
g/cm ² , foam density including skin layer from 0.02g
It is preferable that the tensile strength is 0.5 g/cm ² or more, and the tensile strength is 0.3 Kg/cm ² or more. If the 25% compression hardness is lower than 15g/ ^cm2 , the rebound stress during compression is small, resulting in poor adhesion to the other segment and poor water-stopping properties.
If it exceeds g/cm ² , the repulsion stress becomes too large, resulting in problems such as workability and damage and movement of the water stop material during segment assembly. If the density exceeds 0.5 g/cm ² , it approaches a non-foamed material and will break, deform, or move due to the shear force in the compressed state during handling work up to assembly and when assembling the segments with a shield jacket key. If it is lower than 0.02g, a high compressibility is required, making it difficult to prevent water leakage. The tensile strength is preferably 0.3 Kg/cm ² or more, preferably 0.6 Kg/cm ² . If it is lower than this, it may be damaged during work and cause water leakage. Examples of the foam used in the present invention include polyacrylic resin, polyurethane resin, polyvinyl chloride resin, polyolefin resin such as polyethylene and polypropylene, natural rubber such as red sponge, and ethylene propylene commonly referred to as EPM and EPDM. Examples include foams such as rubber and synthetic rubber such as chloroprene rubber. However, polyvinyl chloride resins, ethylene propylene rubber, chloroprene rubber and polyurethane resins, particularly foams of polyurethane resins, are preferred. Although a general-purpose polyurethane resin foam may be used, it is preferable that the urethane composition constituting the foam is hydrophobic. Examples of hydrophobic urethane foams include those synthesized by using active hydrogen compounds such as diene-based, dimer acid-based, castor oil-based, or tall oil-based compounds in a polyhydroxy compound as a raw material. However, it is not limited to these hydrophobic foams, and a 10 mm thick piece of the foam is sandwiched between aluminum foil and heated to 180 to 200 mm.
℃ and a pressure of 40 to 50 kg/cm ² to form a film, and the contact angle with water is at least 90 degrees. When actually constructing the water stop material of the present invention, the effect can be further enhanced by satisfying the following conditions. When assembling segments with waterproof material pasted, it is important to ensure that the average compressed density of the waterproof material after installation is at least
The amount should be 0.25 g/cm ³ or more, preferably 0.4 g/cm ³ or more. Also, when assembling the segments, the pressure applied to the water stop material attached to the segments must be at least 10 kg/cm ²
It is preferable to compress with a force of 50 kg/cm ² or more. As shown in Figure 5, the waterproofing material can be pasted around the entire surface of segment 1 with at least one of the skin layers positioned at right angles to the segment surface, or around two sides of the segment and its end corners. It is preferable to attach it to In addition, when joining the water-stop material in the middle of the side surface of the segment, there are three methods shown in Figure 6, especially 6-1 and 6.
-2 method is better. As shown in Figure 7, the method of pasting the water-stopping material at the corner of the segment is to paste the main water-stopping material with other water-stopping materials of the same or different types in parallel and in contact with each other, or It is preferable to apply the adhesive material 10 from above. Also, after assembling the waterproof material into segments,
By injecting a backing material and impregnating the communication hole of the water stop material with the backing material, the prevention property can be improved. In the case of conventional non-foamed solid water stop materials and closed cell solid water stop materials, the water stop performance does not change particularly depending on the presence or absence of a backing material. However, since the water stop material of the present invention is made of open-cell foam, it is preferable to compress it before use. Therefore, when assembling the segments, there may be some areas where the compressibility is low, which may reduce the water-stopping performance. In this case, when the backing material is injected, the backing material enters into the air bubbles of the water-stopping material, and the water-stopping performance can be improved. It is preferable to inject the backing material within 50 hours after the primary lining escapes from the tail. When the injection period exceeds 100 hours, gravel, etc. will fall into the tail void and fill it.
The backing material is not filled sufficiently and the water-stopping performance deteriorates. Adding bentonite-based filler to the backing material will have a greater effect. The mixing ratio of cement and bentonite is 1:0.1~1:1, especially 1:0.2~
1:1 is preferred. The air permeability of the foam of the present invention is preferably 140 c.c./cm ² /sec or less, preferably 50 c.c./cm ² /sec or less. If the air permeability is greater than 140 c.c./cm ² /sec, it will be difficult to waterproof even when compressed, and when injecting the backing material after segment assembly, the backing material will be densely packed into the foam cells. It is not possible to improve waterproof performance without filling the water. The air permeability referred to here is based on JIS-L-1004, Frazier method when the foam thickness is 10 mm. In addition, in the present invention, the open cell ratio of 51% or more means that the open cell ratio is 51% or more after segment assembly.
% or more. Therefore, even if the open cell ratio is 51% or less before segment assembly, the open cell ratio is increased to 51% or more upon segment assembly. If the tensile strength of the foam is less than 51% with a tensile strength of 3 kg/cm ² or less, when assembling segments,
Easy to create open cells. This type of foam falls within the scope of the present invention even if the open cell ratio before compression is less than 51%. The skin layer may be formed during the production of the foam, or the skin layer may be formed on a foam that does not have a skin layer by post-treatment using an adhesive or a melting method. As shown in FIG. 8, it is preferable that the skin layer be provided on multiple surfaces rather than on one surface (2), (3), and (4). Examples 1 to 8 Water stop materials having the following compositions and structures were made and water leakage tests were conducted. The size of the waterproof material is 10 mm thick and 10 mm wide.
A punched hole with an inner diameter of 55 mmφ was formed. Waterstop material 1 Hydrophobic polyurethane foam (foamed using dimer acid polyester polyol, tolylene diisocyanate, and water) having a skin layer on one side. 2 Hydrophobic polyurethane foam (same foam as 1 above) with skin layers on two symmetrical sides. 3 Hydrophobic polyurethane foam (same foam as in 1 above) with skin layers on four sides. 4 Polyvinyl chloride flexible foam (foamed from vinyl chloride resin plasticized with dioctyl phthalate) with a skin layer on one side. 5 Polyether type urethane foam (foamed using polypropylene ether glycol, tolylene diisocyanate, and water) with a skin layer on one side. 6 Polyester-type urethane foam (foam foamed with polyester synthesized from aditic acid, diethylene glycol, and trimethylolpropane, tolylene diisocyanate, and water)
and has a skin layer on one side. 7 Ethylene propylene, diene rubber (a foam made by mixing polyethylene propylene rubber with fillers such as naphthenic extender oil, low-molecular polyolefin, butyl rubber, and foaming with an organic foaming agent),
Something with a skin layer on one side. 8 Polyethylene open cell foam (polyethylene resin mixed with low molecular plasticizer and foamed)
It has a skin layer on one side. In addition, the skin layer was formed by one piece in the case of polyurethane foam, but in the case of other resin foams, adhesive,
A skin layer was formed in post-treatment using an adhesive. The physical properties of these waterproof materials were as follows.

[Table] Note that 1. Tensile strength was measured using a JIS6301 vulcanized rubber testing machine. 2. Hardness was measured according to JISA9514 hard urethane foam insulation material compression hardness test. 3. Regarding the standard conditions of the test location, please refer to JISZ8703.
-Measurements were made under the standard temperature and humidity conditions of Class 3 in 1976. Comparative Examples 1 to 3 1 Hydrophobic polyurethane foam (foam in Example 1) without a skin layer. 2 Ethylene propylene diene rubber foam (same foam as Example 7) without a skin layer. 3 Open-cell polyethylene foam (same foam as in Example 8) without skin layer. The results of the water leakage test were as follows. A test apparatus shown in FIG. 9 was used in this test. 13 is a water pressure inlet, 14 is a water container, 15 is water, 16 is an aluminum compression plate, 17 is a bolt for setting thickness, 18 is a spacer, and 2 is a water stop material.

【table】

[Table] The test was conducted at a water pressure of 2 Kg/cm ² . As is clear from this result, providing the skin layer has an excellent effect on water leakage resistance.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the segment, Figure 2 is a perspective view of a partially assembled segment, Figure 3 is a cross-sectional view after shield construction, Figure 4 is a sub-sectional view after shield construction, and Figure 5. , FIG. 6 and FIG. 7 are diagrams showing how the water-stopping material is attached to the segments, FIG. 8 is a longitudinal sectional view of the water-stopping material of the present invention, and FIG. 9 is a longitudinal sectional view of a water leakage test device. 1: Segment, 2: Water stop material, 3: Backing material,
8: Shield jacket, 8: Shield body, 9:
Pasting material, 11: Skin layer, 12: Foam, 13:
Water pressure inlet, 14: water container, 15: water, 16: compression plate, 18: Spencer.

Claims (1)

[Scope of Claims] 1. A water-stopping material for assembling a shield segment, which is a rubber or plastic foam with an open cell ratio of 51% or more and has a skin layer on at least one surface. 2 In the direction perpendicular to the plane almost perpendicular to the skin layer
Claim 1, wherein the foam has a 25% compression hardness of 15 g/cm 2 to 500 g/cm ² , an average density of the foam including the skin layer of 0.5 g/cm ³ or less, and a tensile strength of 0.3 Kg/cm ² or more. waterproof material. 3. When applying a water-stopping material that is a rubber or plastic foam with an open cell ratio of 51% or more and has a skin layer on at least one surface to the shield segment, the skin layer should be approximately equal to the surface of the segment on at least one surface. A shield construction method characterized by making the shield segments at right angles, setting the shield segments in a ring shape after pasting, and injecting backing material into the back of the segments.