JPH0641720B2 - Tunnel lining method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for applying a secondary lining after a primary lining using a segment when constructing a tunnel by a shield method. is there.

Conventional technology Until now, in constructing a shield tunnel, the primary lining was performed with a prefabricated structure using segments, and as a finish that also functions as reinforcement, corrosion protection, meandering correction, waterproofing, etc.
Secondary lining is usually done by placing concrete.

However, in this secondary lining with concrete,
Normally, the thickness should be 15 to 30 cm, so the tunnel excavation cross section must be unnecessarily large, the amount of concrete used is large, and it takes a long time to dry, so the construction period becomes long. I cannot escape. Also,
You have to prepare special equipment for casting,
If air is entrained during casting, it will cause voids and cracks after drying, which is an inconvenience to work because air must be appropriately vented.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention does not have the drawbacks associated with the conventional secondary lining of concrete, can be easily and easily constructed, and can be used for placing concrete to make the tunnel excavation cross section as small as possible. The purpose was to provide a new secondary lining method that should replace the above.

Means for Solving the Problems As a result of various studies on the secondary lining in the shield tunnel, the present inventors have found that if a specific room temperature curable polyurethane resin is spray-painted by a special means,
It was found that a thickness equal to that of a secondary lining made of concrete can be obtained with a thickness of 10 mm, and the present invention has been completed based on this finding.

That is, in the present invention, in applying a secondary lining to a shield tunnel, a first liquid containing a polyol component and a crosslinking agent component mixed with an epoxy resin-modified polyol, and a second liquid containing a polyisocyanate component are statically charged. While maintaining a sprayable viscosity while mixing with a mixer, spray paint on the surface of the primary lining segment,
The present invention provides a tunnel lining method characterized by curing.

The primary lining to which the secondary lining is applied by the method of the present invention may be a prefabricated structure of segments applied by a conventional method and is not particularly limited.

The secondary lining according to the present invention is applied after performing a pretreatment for waterproofing and cleaning as usual for the primary lining thus applied.

In the method of the present invention, a coating liquid composed of a first liquid containing a polyol component containing an epoxy-modified polyol and a crosslinking agent component and a second liquid containing a polyisocyanate component is used. When this mixture of the first liquid and the second liquid is maintained, the viscosity that can be sprayed is maintained in the initial stage, but thereafter, a rapid curing reaction occurs within a short time, and the viscosity increases. That is, it maintains a viscosity of 50,000 centipoises or less at 20 ° C for at least 30 seconds after mixing the two liquids, but increases to a viscosity of 100,000 centipoises or more in 5 minutes at the longest. A uniform coating can be applied without the occurrence.

The polyol component used in the first liquid can be arbitrarily selected from those conventionally used as the polyol component of the room temperature curable two-component polyurethane resin composition. Examples thereof include organic dicarboxylic acids such as phthalic acid, adipic acid, dimerized linoleic acid, and maleic acid, and ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, trimethylolpropane, hexanetriol, glycerin, and triglyceride. Polyester polyols derived from polyhydric alcohols such as methylolethane and pentaerythritol, and polyester polyols derived from lactones such as polybutyrolactone and polyvalerolactone, castor oil or modified polyols, and poly (oxypropylene) Glycol, poly (oxypropylene) poly (oxyethylene) glycol, poly (oxybutylene) glycol, poly (oxytetramethylene) glycol, poly (oxypropylene) ) Triol, poly (oxypropylene) poly (oxyethylene)
Polyols such as triols, poly (oxypropylene) poly (oxyethylene) poly (oxypropylene) triols, polyether polyester polyols containing both the polyester and polyether units mentioned above, and acrylics derived from acrylic acid. Among polyols, those having a molecular weight of 300 to 3000 and a hydroxyl value of 50 to 350 can be mentioned. These polyols may be used alone or in combination of two or more.

In the coating liquid used in the method of the present invention, it is necessary to blend an epoxy-modified polyol in such a polyol component. As this epoxy-modified polyol, an epoxy compound may be added to the polyester polyol or polyether polyol described above. For example epihalohydrin,
Those obtained by reacting glycidyl alcohol and the like are used. The epoxy-modified polyol is blended in a proportion of at least 5% by weight based on the total amount of the polyol component. By blending the epoxy-modified polyol in this way, it is possible to suppress the decrease in the strength of the coating film due to rapid curing, and to give permanent resistance to impact and abrasion.

Next, in the first liquid, as a cross-linking agent component used in combination with this polyol component, aliphatic diols such as ethylene glycol, propylene glycol, butylene glycol, pentanediol, diethylene glycol and dipropylene glycol, ethylenediamine, propylenediamine , Butylenediamine, aliphatic diamines such as pentamethylenediamine, aniline, phenylenediamine, 4,4'-methylenediamine, 2,2-bis (p-aminophenyl) propane, 3,3'-dichloro-4, Aromatic amines such as 4'-diaminophenylmethane and 1,2-bis (2-aminophenylthio) ethane are used. In the present invention, it is advantageous to use, from among these cross-linking agents, one having a fast reaction rate and one having a slow reaction rate in combination. By using such a combination, it is possible to prevent sagging due to a rapid curing reaction and, at the same time, secure a time during which handling during coating is possible. As the crosslinking agent having a high reaction rate and the crosslinking agent having a slow reaction rate, a mixture of two or more kinds may be used. The ratio of these used is appropriately in the range of 1: 1 to 1:20 in terms of the ratio of the total weight of the crosslinking agent having a fast reaction rate and the total weight of the crosslinking agent having a slow reaction rate.

In addition to the above-mentioned components, the first liquid contains, if desired, extenders such as silica, talc, calcium carbonate and barium sulfate, iron oxide yellow, light yellow 50, iron oxide brown, iron oxide red, light blue. 100, Chrome oxide green GN color pigments, organotin compounds, organolead compounds catalysts, amine wetting agents adhesion improvers, etc. Can be included.

And this 1st liquid has a viscosity of 1000-35 at 20 degreeC.
It is desirable to select and prepare each component so that it becomes 00 centipoise.

Next, in the coating liquid used in the method of the present invention, it is necessary to use the polyisocyanate component in the second liquid.
Examples of the polyisocyanate component include hexamethylene diisocyanate, octamethylene diisocyanate, tolylene diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane-4.4'-diisocyanate, biphenyl-4,4'-diisocyanate, and 2,2.
-Polyphenyl isocyanate used in ordinary polyurethane resin paints such as diphenylpropylene-p, p'-diisocyanate can be used, and particularly, these polyisocyanates can be used as phosphoric acid, acetic acid, oxalic acid, succinic acid, and maleic acid. Those modified with an acid such as or an acid ester such as ethylhexyl phosphate, pentyl phosphate, octyl phosphate are preferable.

Usually, in such a thick film type coating composition, if the polyisocyanate component is used as it is as the second liquid component, it is difficult to obtain a uniform and smooth coating film because the reaction rate is high. Further, if the prepolymer is used, the reaction rate can be controlled so that such a drawback can be eliminated, but since the viscosity becomes high, it is necessary to take a long time for leveling.

However, when the polyisocyanate modified with an acid or acid derivative as described above is used, it is possible to suppress a rapid reaction without increasing the viscosity as in the case of a prepolymer, and it is possible to handle in a short time. And a uniform and smooth coating film can be formed.

The second liquid is preferably prepared so that the viscosity at 20 ° C. is 100 to 300 centipoise.

In the method of the present invention, since the coating liquid to be used is highly reactive, it is necessary to mix the first liquid and the second liquid immediately before coating, atomize this, and then coat it. Use a static mixer. This static mixer has a structure in which a specially shaped stirring screw is placed in a metal pipe, and the 2
The kinds of liquids are mixed in such a manner that the liquids are divided into halves in order from the supply port to the discharge port and are alternately combined and finely dispersed. Therefore, according to this method, unlike the case of collision mixing by a two-headed gun or the like, there is no risk of air being mixed in, and moreover, uniform mixing can be performed in a short time. The first liquid and the second liquid thus mixed are spray-coated while the sprayable viscosity is maintained. In the general coating method, it is not possible to prevent dripping on the slope and ceiling surface unless spraying is as small as 1 minute per minute, but in the method of the present invention, dripping occurs even at a high spraying speed of 2 to 4 per minute. It can be applied without coating and is very efficient.

In this way, 1 to
After applying the coating liquid with a thickness of 10 mm, it is dried and cured.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The figure is an explanatory view showing an example of a spray device used in the method of the present invention, in which the first liquid is stored in a tank 1, passes through a conduit 3 by a pressure pump 2, a filter 4, a heater 5, a metering device. It is sent to the mixing chamber 7 via the pump 6. On the other hand, the second liquid is similarly sent from the tank 1'to the mixing chamber 7 by the pressure pump 2 through the pipe 3 ', the filter 4', the heater 5'and the metering pump 6 '. The first liquid and the second liquid mixed in the mixing chamber 7 are uniformly mixed by a static mixer 8 and sprayed onto a surface to be coated by a spray gun 9. Reference numeral 11 denotes a pump for promptly washing and removing the mixed paint in the spray gun 9 and the hose.

The first liquid is usually heated to a temperature of 30 to 80 ° C, adjusted to a viscosity of 200 to 1000 cps, and mixed with the second liquid. The mixing ratio of the first liquid and the second liquid is usually such that a polyol component obtained by adding an epoxy-modified polyol to a polyol such as polyester polyol or polyether polyol in the first liquid and active hydrogen of an amine component or a diol component. The total number of moles and the number of moles of the isocyanate groups of the diisocyanate component in the second liquid are selected to be approximately the same, but either one can be used in excess if desired.

In the method of the present invention, during the secondary lining, a desired surface may be preliminarily coated with a primer of a polyurethane paint, if desired. This primer may be either a one-component polyurethane-based paint or a two-component polyurethane-based paint, but toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, acetone, ethyl acetate, butyl acetate, methyl glycol acetate,
It is used after diluting with a solvent such as ethyl glycol acetate. As a one-component polyurethane coating used as a primer, for example, polyether polyol, polyester polyol, castor oil, etc., TDI, MDI, HMDI
There are moisture-curable urethane coatings obtained by excessively reacting with, and thermosetting urethane coatings containing blocked isocyanate blocked with phenol and the like and polyester polyol.

Also, as an example of a two-component polyurethane-based paint, the molecular weight is
A first liquid containing a polyester polyol, a polyether polyol, an epoxy-modified polyol or a mixture thereof having a hydroxyl value of 300 to 3000 and a hydroxyl value of 50 to 350 mg / g, and modified diphenylmethane handling 4,4′-diisocyanate and modified biphenyl-4,4 ′. -Diisocyanate, modified
Mention may be made of a second liquid containing a diisocyanate such as 2,2-diphenylpropane-p, p'-diisocyanate.

In addition to the above-mentioned components, these polyurethane-based paints for primers may further contain additives commonly used in ordinary polyurethane-based paints such as extender pigments, coloring pigments, catalysts and modifiers.

These primers are applied in a film thickness of 10 to 100 μm, preferably 20 to 50 μm on a desired surface by a brush, a roller, an airless coating machine or the like.

In this way, by spraying the required polyurethane resin composition on the surface of the primary lining subjected to the primer treatment using the above-mentioned spraying device in an amount such that the thickness after curing becomes 1 to 10 mm, 1 It is possible to obtain a coating film having a film thickness without sagging or unevenness due to nonuniformity of the film thickness by a single operation.

The coating film of the secondary lining thus obtained has a tensile strength of 10
It has a hardness of 0 kg / cm ² or more, a Shore D hardness (20 ° C.) of 50 or more, and an adhesive strength of 80 to 150 kg / cm ² , and has physical properties comparable to or better than the conventional secondary lining with concrete.

EFFECTS OF THE INVENTION According to the present invention, by applying a coating film of only 1 to 10 mm, a secondary lining comparable to or superior to the case of conventional concrete can be achieved, thus saving materials and equipment. In addition to many advantages in terms of work such as simplification of the work and shortening of the construction period, there are no defects that cause reduction of voids or cracks in the secondary lining structure.
It has the advantage that no repair is required for a long period of time.

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Example 1 A shield tunnel was subjected to a primary lining of a circular prefabricated structure using a concrete-based segment, the surface was thoroughly washed with water, and after drying, a first liquid having a composition shown in Table 1 was prepared.
Diethylhexyl phosphate modified diphenylmethane-
A second liquid composed of 4,4'-diisocyanate and a volume of 75 /
It was used at 25 and was applied to a thickness of 5 mm by the spray device shown in the figure.

In this way, a smooth and uniform coating film was obtained without any sagging or unevenness in any case. After 24 hours, all of these coating films exhibited a cohesive failure strength of concrete, that is, an adhesive strength of more than 20 kg / cm ² , and a tensile strength of 100 kg / cm ² or more.

Example 2 After the primary lining of Example 1 was applied, the surface was washed with water,
Dried. On top of that, first polyester-based moisture-curable urethane resin (molecular weight 2500, isocyanate content 1.6%)
A paint consisting of 40% by weight, 15 parts by weight of silica powder and 45 parts by weight of an equal volume mixture of toluene, xylene and ethyl acetate was applied by an airless coater to form a primer layer having a thickness of 20 μm.

Then, a two-component room temperature curing type polyurethane resin composition having the same composition as in Example 1 was applied thereon in the same manner as in Example 1 to obtain a coating film having a film thickness of 7 mm. After curing for 48 hours,
A secondary lining with sufficient strength was obtained.

[Brief description of drawings]

The figure is an explanatory view showing an example of a spray device used in the method of the present invention. In the figure, 1 is a first liquid tank, 1'is a second liquid tank, 2, 2'is a pressure pump, 5, 5'is a heater, 6, 6'is a metering pump, 7
Is a mixing chamber, 8 is a static mixer, and 9 is a spray gun.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fujio Tsuzuki, 428-5, Uene, Tsumanauma-cho, Oza-gun, Saitama Prefecture (72) Koichi Sandou 2-12-17, Kaishin, Funabashi-shi, Chiba (72) Inventor, Narabe Hiroshi 1556-4, Masudaishi, Kashiwa-shi, Chiba Prefecture (72) Inventor Yukio Nakamoto 163-818 Miyawada, Fujishiro-cho, Kitasoma-gun, Ibaraki Prefecture (72) Ichiro Hirono 2-7-22, Higashi-cho, Kodaira-shi, Tokyo (56) References JP-A-61-19683 (JP, A) JP-A-58-4097 (JP, A) JP-A-59-193948 (JP, A) JP-B-56-36280 (JP, B2)

Claims (1)

[Claims] 1. A static mixer comprising a first liquid containing a polyol component containing an epoxy resin-modified polyol and a cross-linking agent component, and a second liquid containing a polyisocyanate component when a secondary lining is applied to a shield tunnel. A tunnel lining method characterized by spray-painting and curing the surface of the segment that has been subjected to the primary lining while maintaining a sprayable viscosity while mixing.