JP2019183593A - Affixing and freezing method - Google Patents

Abstract

To provide an affixing and freezing method that can easily and reliably affix a freezing duct to a structure and efficiently transmits a chill that a coolant has in the freezing duct to the structure.SOLUTION: The affixing and freezing method of the present invention includes affixing a freezing duct (1) to an underground structure (10: a structure such as a segment or a steel sheet pile), and freezing a ground (G) on the rear face side (opposite side to the freezing duct 1) of the structure (10) on which the freezing duct (1) is affixed. The freezing duct (1) is affixed to the structure (10) using a filler material (2) that includes one of granular bodies of a metal, an oxide of the metal and an alloy whose main component is the metal as well as a sealing material, and that has both heat conductivity and tight-fitting properties.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pasting and freezing method in which a freezing tube is attached to a structure such as a segment or a steel sheet pile, and the ground on the back side (opposite side of the freezing tube) of the structure to which the freezing tube is attached is frozen.

The pasting freezing method has been well known (for example, Patent Document 1), and is a construction method in which a freezing tube is pasted on a structure to freeze the ground on the back of the structure. Here, the surface of the structure is often a curved surface and has irregularities, so the cold heat of the freezing tube is transferred to the ground on the back of the structure and the structure through a padding material between the structure and the freezing tube. The freezing method is used.
In the prior art, quick setting mortar or concrete is used as a filling material between a structure and a freezing pipe. However, the thermal conductivity of quick setting mortar and concrete is not good. In addition, the mortar that is the interstitial material contracts and peels during the curing process, and as a result, a space may be interposed between the freezing tube and the structure. If a space is interposed between the freezing tube and the structure, the space acts as a heat insulating material, and the cold heat of the refrigerant (brine, liquefied carbon dioxide, etc.) in the freezing tube is not efficiently transmitted to the structure. The ground on the back side of the structure may not be frozen efficiently.

  Conventionally, the freezing pipe used in the pasting freezing method uses a steel square pipe with a cross-section of 100 mm in width and 50 mm in height, and since the unit weight is heavy, it is necessary to install a wide square pipe with a width of 100 mm or more. The work is difficult. On the other hand, in the ground freezing method using liquefied carbon dioxide as the circulating refrigerant in the freezing pipe, both a flat shape and a non-flat shape made of a metal having a good thermal conductivity (for example, aluminum) called “microchannel” It is also conceivable to use a pipe (freezing pipe) including a plurality of minute refrigerant flow paths as a freezing pipe. The unit weight of the microchannel is light and the installation work is easy. Since the microchannel is lightweight, the installation work is easy even if it is 100 mm or more in width, but the height is about 5 mm, and since it is made of aluminum, the rigidity in the freezing tube axial direction as well as the rigidity in the cross section is low. . Therefore, like the installation work of the conventional steel square pipe, the mortar was used as a filling material, and the microchannel was forcibly attached to the structure so as to be pressed using the weight and rigidity of the steel square pipe. In such a case, the freezing tube itself bends, or the thickness of the filling material varies. And the malfunction that a predetermined ground area cannot be frozen, the malfunction that frozen ground temperature is high, or the malfunction that a freezing period takes long generate | occur | produces.

JP 2017-101452 A

  The present invention has been proposed in view of the above-described problems of the prior art, and can attach a freezing tube to a structure easily and reliably, and the cooling heat possessed by the refrigerant in the freezing tube is efficient for the structure. The purpose is to provide a freezing method of sticking that is transmitted automatically.

The pasting freezing method of the present invention is:
The frozen tube (1) is attached to the underground structure (10: segment, steel sheet pile, etc.), and the back side (opposite side of the frozen tube 1) of the structure (10) to which the frozen tube (1) is attached In the pasting freezing method to freeze the ground (G),
Uses a filling material (2) containing a fine particle of any of metal, an oxide of the metal, and an alloy containing the metal as a main component, a sealing material, and having both thermal conductivity and adhesion The freezing tube (1) is attached to the structure (10).
Here, generally, the metal powder has a risk of explosion or fire as shown as a dangerous material type 2 defined by the Fire Service Law, and aluminum powder is particularly dangerous. In the example of aluminum powder, what passes through a mesh sieve having an opening of 150 microns is 50 wt% or more, and is not considered as a second kind of combustible solid at a specified quantity of 100 kg. In addition, metal powder has the possibility of dust explosion, and it is generally said that the particle size limit of fine powder causing dust explosion is 100 to 0.1 microns. The microparticles used in the present invention can be considered when mixing materials at the place where the paste freeze tube is installed, considering the safety against the fine powder, and the amount used may be small or large, Further, since the fine particles to be used have a particle size distribution, it is preferable that the fine particles have an average particle diameter of 100 microns or more as a guide.
As a method for measuring the average particle diameter of the fine particles, a measurement method by a laser diffraction / scattering method (microtrack method) is preferable. When one particle is irradiated with a laser beam, light called “diffracted / scattered light” is emitted from the particle in various directions. This “diffracted / scattered light” draws a certain spatial pattern in the direction in which the light is emitted. This is called a “light intensity distribution pattern” and is supposed to take various shapes depending on the diameter of the particles. By detecting this pattern, the particle diameter can be determined. When measuring samples made of particles of various sizes, the light intensity pattern is an overlay of the diffracted and scattered light from each particle. In the laser diffraction / scattering method, by detecting and analyzing a light intensity pattern, the particle diameter and the ratio of particles contained therein can be obtained. Based on this, the particle size distribution is calculated. The standard for representing the particle size distribution includes the number, area, and volume, and there are a frequency distribution and an integrated distribution as methods for representing the distribution. In the present invention, the standard for expressing the particle size distribution is preferably a volume standard.
In addition, the cumulative distribution is preferably used for the representation of the particle size distribution.
The average particle diameter is preferably set to the “median diameter (50% particle diameter)” as the average particle diameter based on the cumulative distribution based on the volume described above.

  In the present invention, the sealing material is preferably a silicone sealing material. Of the silicone sealants, a one-pack type silicone sealant that is easy to work with is preferable.

In the present invention, the metal is preferably aluminum, and the oxide of the metal is preferably aluminum oxide (alumina: Al ₂ O ₃ ).
Examples of the metal-based alloy (aluminum-based alloy) include duralumin, aluminum manganese alloy, aluminum magnesium alloy, and aluminum zinc magnesium alloy.

In the present invention, it is preferable that the metal is copper and the oxide is copper oxide.
In this case, examples of the alloy containing the metal as a main component (alloy containing copper as a main component) include bronze, brass, white bronze, and brass.

And in this invention, it is preferable that the said padding material (2) maintains the adhesiveness of the said freezing tube and the said structure in normal temperature--50 degreeC. That is, even when the frozen freezing tube is installed at a normal temperature before the freezing tube is filled with the circulating refrigerant, the freezing tube is filled with the circulating refrigerant, the low-temperature refrigerant is circulated, and the freezing maintenance operation is performed. It is desirable that the interlining material (2) maintains the adhesion between the freezing tube and the structure.
Here, maintaining the adhesion of the filling material (2) means that when the frozen tube is attached to the structure, the sealing material contained in the filling material is before solidification, and the surface of the frozen tube and the structure surface Maintain the adhesion state, and then maintain the adhesion state while the sealing material solidifies and maintains the adhesion state where the frozen tube does not easily peel off from the structure even if force is applied. It shows that.

Moreover, in this invention, it is preferable that the said padding material (2) keeps thermal conductivity in normal temperature--50 degreeC after sticking. That is, after the pasted freezing tube is installed, in the state where the freezing tube is filled with the circulating refrigerant, the low-temperature refrigerant is circulated, and the freezing maintenance operation is performed, the interlining material (2) has its thermal conductivity. It is desirable to hold it.
In general, silicon cannot be said to have high thermal conductivity compared to metals and the like, and the filling material (2) of the present invention, which mainly uses a silicone sealant material, also has high thermal conductivity compared to metals and the like. That's not true. However, the heat conductivity as a filling material can be improved by mixing fine particles made of metal into the sealing material. And since a silicone type sealant material is strong to a temperature change, the heat conductivity can be hold | maintained also to the sudden heat change of normal temperature--50 degreeC.
In addition, the interlining material retains the adhesiveness, thereby maintaining the continuity of the heat transfer path of the freezing tube, the interlining material, and the structure, and maintaining the thermal conductivity necessary for freezing. Can do.

According to the pasting and freezing method of the present invention having the above-described configuration, the metal, the oxide of the metal, and containing any fine particles of an alloy containing the metal as a main component, and containing a sealing material, The freezing tube (1) is affixed to the structure (10) using the interlining material (2) having both thermal conductivity and adhesion, and the sealing material contained in the interlining material (2) is bonded. Since it has a function as a material, the freezing tube (1) can be easily and reliably attached to the structure (10) by the close contact action of the sealing material.
The sealing material having adhesiveness does not dry and solidify after being applied, and even if it is cooled to lower the temperature, the sealing material itself does not separate and peels from the freezing tube (1) or the structure (10). Since it is difficult, a space is not formed between the freezing pipe (1) and the structure (10), and the cold heat of the refrigerant flowing through the freezing pipe (1) is structured by interposing a space as a heat insulating layer. The situation where it becomes difficult to be transmitted to the object (10) is prevented.

Further, the filling material (2) of the present invention contains fine particles of any of a metal, an oxide of the metal, and an alloy containing the metal as a main component, and the metal, an oxide of the metal, Since all the alloys containing the metal as a main component are excellent in thermal conductivity, the thermal conductivity of the filling material (2) is also good. Therefore, the cold heat of the refrigerant flowing through the freezing pipe (1) is efficiently transmitted to the structure (10) via the padding material (2) having good thermal conductivity, and the ground ( G) is transmitted efficiently. As a result, the ground (G) on the back side of the structure (10) is efficiently frozen.
And since any of a metal, an oxide of the metal, and an alloy containing the metal as a main component is contained as a fine particle in the filling material (2), the surface of the freezing tube (1) and the structure (10 ) A metal, an oxide of the metal, and an alloy containing the metal as a main component do not form irregularities on the surface, and the adhesiveness of the sealing material is mainly used to maintain the adhesion. Conversely, when the surface of the freezing tube (1) and the surface of the structure (10) are uneven, the metal, the oxide of the metal, and the alloy containing the metal as a main component are very small. The adhesiveness to the uneven surface is maintained by the plasticity of the sealing material.

The sealing material contained in the filling material (2) of the present invention is a silicone sealing material, and the silicone sealing material is used as a filling material between the freezing pipe (1) and the structure (10). When the freezing tube (1) and the structure (10) are pasted, they exhibit adhesiveness (adhesion) and there is almost no curing shrinkage even after curing. Therefore, the continuity of the heat transfer path of the freezing tube, the filling material, and the structure is maintained.
Silicone-based sealant is a polymer material, but it has excellent heat resistance due to its low glass transition point. Silicone sealant is a filling material even if it is changed from room temperature to extremely low temperature in a short time as in the pasting freezing method. The function as is not impaired.

  In the present invention, if the metal contained in the filling material (2) is aluminum, the oxide is aluminum oxide, the alloy is an aluminum alloy, and these are used as fine particles, aluminum fine particles, aluminum oxide Microparticles and aluminum alloy microparticles are mainly composed of aluminum, and since aluminum exhibits a high thermal conductivity of about 200 W / mK, the above-mentioned microparticles also have a higher heat than, for example, about 50 W / mK of iron. Shows conductivity.

  If the metal contained in the filling material (2) of the present invention is copper, the oxide is copper oxide, the alloy is a copper alloy, and these are used as fine particles, copper fine particles, copper oxide fine particles Since the grains and copper alloy fine grains are mainly composed of copper, and copper exhibits a high thermal conductivity of about 380 W / mK, the above-mentioned fine grains are also higher in heat conductivity than, for example, about 50 W / mK of iron. Showing gender.

The filling material (2) of the present invention maintains the adhesion between the freezing tube (1) and the structure (10) in a temperature range from room temperature to −50 ° C., and is frozen using the filling material. In addition to having adhesiveness at room temperature when the tube is pasted, the refrigerant is passed through the freezing tube after the freezing tube has been pasted to the structure, rapidly transferring cold heat from the freezing tube, Although the temperature decreases rapidly, the adhesion of the filling material is maintained, so there is no separation or voids at the interface between the freezing tube and the filling material or between the structure and the filling material. The cold heat from the freezing pipe can be effectively transmitted to the structure, and as a result, the ground on the back of the structure can be efficiently frozen.
The sealing material is a silicone sealant, and no curing heat is generated even if the filling material is cured after the freezing tube is attached to the structure using the filling material of the present invention. On the other hand, mortar and concrete of the prior art generate a large amount of heat of hardening of the cement, and freeze tubes and structures are often made of steel, causing thermal expansion and contraction. However, the hardening of the cement converges, and the frozen pipe, the filling material, and the structure are thermally contracted, resulting in a loss of mutual adhesion. According to the present invention, there is no loss of adhesion due to the heat of curing of the filling material.

  The filling material (2) of the present invention retains thermal conductivity as a material in a temperature range from room temperature to −50 ° C. after being attached, and after the freeze tube is attached to the structure, the sealing material is silicone. Since it is a high-temperature sealant and has excellent temperature resistance, the thermal conductivity of the padding material is maintained even if a coolant is passed through the freezing tube and cold heat is rapidly transmitted from the freezing tube and the temperature of the padding material is rapidly lowered. Since it is held, cold heat from the freezing pipe can be effectively transmitted to the structure, and as a result, the ground on the back of the structure can be frozen efficiently.

It is explanatory drawing of the stick freezing tube used by embodiment of this invention. It is explanatory drawing which shows the state which stuck the freezing pipe | tube via the padding material when constructing the sticking freezing method of embodiment. It is a figure which shows the experimental result regarding the heat conductivity of the sealing material of a filling material, and adhesiveness (adhesion) as a table | surface. It is a figure which shows the experimental result regarding the effect which added the aluminum oxide (alumina) to the sealing material as a table | surface. It is explanatory drawing which shows the state which constructed the sticking freezing construction method. It is explanatory drawing which shows the modification of freezing tube sticking.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Here, in the illustrated embodiment, liquefied carbon dioxide (CO ₂ ) is used as a secondary refrigerant circulating in the freezing tube 1. However, as the circulating secondary refrigerant, liquefied gas other than liquefied carbon dioxide or brine can be used as the refrigerant if the boiling point is low enough to supply the cold heat necessary for construction of the ground freezing method. There is no need to limit the circulating secondary refrigerant to liquefied carbon dioxide.
First, referring to FIG. 1, a mode in which the cryotube 1 is attached to the structure 10 will be described. Here, the structure includes, for example, a rear trunk portion of a shield machine, a tunnel lining segment, a tunnel or a shield machine, and includes earth retainings, shafts, and existing structures.

In FIG. 1, a freezing tube 1 is a flat plate-like structure 1A (so-called “microchannel structure” or “microchannel”) having a plurality of minute refrigerant flow paths (not shown). The microchannel is made of, for example, aluminum, is lightweight and flexible, and is excellent in radiating cold and absorbing heat (excelling in thermal conductivity). Here, in the illustrated embodiment, the microchannel 1A that is a flat plate member is illustrated, but a microchannel having a shape other than the flat plate shape is also applicable.
Although not explicitly shown in FIG. 1, fluids (refrigerants) flowing in all the micro refrigerant channels of the microchannel 1A flow in the same direction. However, it is also possible to use a part of the plurality of minute refrigerant channels of the microchannel 1A as the refrigerant supply channel and use the remaining minute refrigerant channels as the refrigerant return channel.
In the illustrated embodiment, the case where the freezing tube 1 is a microchannel is described, but a steel square pipe of a conventional technique can also be applied as the freezing tube 1.

In FIG. 1, a dispersion socket 1B provided with a space communicating with a secondary refrigerant supply system (for example, a supply pipe 2A for supplying refrigerant from a ground-side refrigerator) is joined to one end of a flat microchannel 1A. The other end is joined to a collective socket 1C provided with a space communicating with a return system of the secondary refrigerant (for example, a return pipe 2B for returning the refrigerant to the refrigerator on the ground side). In FIG. 1, an arrow F indicated by a dotted line indicates the direction in which the refrigerant flows.
When a refrigerant (for example, liquefied carbon dioxide gas) flows inside the micro refrigerant channel of the microchannel 1A, the back side of the structure 10 (opposite side of the microchannel 1) passes through the structure 10 to which the microchannel 1A is attached. Absorbs the heat of the ground and freezes the ground.
In this specification, the microchannel 1A, the distributed socket 1B, and the collective socket 1C may be collectively referred to as “microchannel”, and may be displayed as “microchannel 1”. Further, the distributed socket 1B and the collective socket 1C are omitted in the drawings other than FIG.

In FIG. 2 which shows the aspect which attaches the microchannel 1 (freezing pipe) to the structure 10, between the microchannel 1 and the structure 10 (for example, steel tunnel lining segment), the interstitial material 2 is interposed. ing.
The left-right direction in FIG. 2 is the longitudinal direction of the microchannel 1, and the direction in which the secondary refrigerant flows is indicated by an arrow F.

In FIG. 2, the plurality of micro refrigerant channels of the micro channel 1 extend in the left-right direction, and the refrigerant (for example, liquefied carbon dioxide, brine) used in the freezing method flows in the direction of arrow F.
As described with reference to FIG. 1, a supply pipe 2 </ b> A for supplying a secondary refrigerant from a ground-side refrigerator is connected to the upstream side (left side in FIG. 2) of the microchannel 1, and downstream of the microchannel 1. A return pipe 2B for returning the secondary refrigerant to the ground-side refrigerator is connected to (on the right side in FIG. 2).
As described above, in FIG. 2, the distributed socket 1B and the collective socket 1C (see FIG. 1) are not shown.

In FIG. 2, the filling material 2 interposed between the microchannel 1 and the structure 10 is required to function as an adhesive that reliably attaches the microchannel 1 to the structure 10. Further, the interlining material 2 is required to have good thermal conductivity so that the cold heat of the refrigerant flowing through the microchannel 1 is efficiently transmitted to the structure 10.
As will be described later with reference to FIGS. 3 and 4, the inventor conducted experiments on the adhesion (adhesion), thermal conductivity, etc. of the interlining material 2 to the freezing pipe and the structure, and the experimental results Based on this, the material component of the interlining material 2 is specified.

The filling material 2 contains a fine particle of any one of a metal excellent in thermal conductivity, an oxide of the metal, and an alloy containing the metal as a main component, and also contains a sealing material. Further, a silicone sealing material is selected as the sealing material.
The interlining material 2 used in the illustrated embodiment uses a silicone-based sealing material as a sealing material and aluminum oxide (alumina: Al ₂ O ₃ ) microparticles as metal oxide microparticles. . Therefore, the interlining material 2 used in the illustrated embodiment has adhesiveness that is a function as an adhesive and has good thermal conductivity.
The inventor uses a one-pack type silicone sealant as the silicone-based sealant, kneads aluminum oxide fine particles into the interstitial material, and interposes the interstitial material between the microchannel and the iron plate. An experiment was conducted to measure the temperature difference between the refrigerant temperature and the iron plate back surface temperature by circulating the refrigerant through the channel and performing a freezing operation.
According to the inventor's experiment, the interlining material 2 used in the illustrated embodiment has a reduced adhesiveness between the freezing tube and the structure in a temperature range of about −50 ° C. during freezing to normal temperature at the time of pasting. I didn't. Moreover, the temperature difference between the freezing tube surface temperature and the iron plate back surface temperature was small, and it was confirmed that the thermal conductivity of the filling material was maintained. Therefore, in the actual sticking freezing method, the interlining material 2 does not lose its adhesion, does not peel off from the structural material 10, and the thermal conductivity is maintained.
The inventor's experiment will be described later.

When a refrigerant (for example, liquefied carbon dioxide) is allowed to flow through the micro refrigerant flow path of the microchannel 1 (freezing pipe) in FIG. 2, the cold heat of the refrigerant flowing through the microchannel 1 is packed with good thermal conductivity. It is efficiently transmitted to the structure 10 via the material 2 and efficiently transmitted to the ground G on the back surface of the structure 10 (opposite side of the microchannel 1).
In addition, the microchannel 1 is reliably attached (adhered) to the structure 10 by the adhesive action of the silicone sealant (sealant) contained in the filling material 2. Since the silicone sealant (sealant) is difficult to peel off from the microchannel 1 and the structure 10, it is prevented that a space is formed between the microchannel 1 and the structure 10 due to the peeling of the filling material 2. The Therefore, the situation where the intervening space acts as a heat insulating material and the heat exchange between the refrigerant flowing through the microchannel 1 and the ground G on the back of the structure 10 is prevented, and the ground G is efficiently frozen. The

[Experimental Example 1]
Experiments were conducted on the thermal conductivity and adhesiveness (adhesion) of the sealing material contained in the filling material. The result is shown in FIG.
In Experimental Example 1, silicone sealant (sample No. 1), mortar (sample No. 2), polymer material (sample No. 3), and heat radiation sheet (sample No. 4) were used as the sealing material. And each sample No1-4 was apply | coated to the microchannel (frozen tube) and appropriate amount, and the apply | coated microchannel was affixed on the iron plate (equivalent to a structure). Then, liquefied carbon dioxide gas was circulated as a refrigerant in the microchannel of the microchannel, and the temperature difference between the microchannel surface and the iron plate (structure) back surface was measured.
Further, after the liquefied carbon dioxide gas was circulated for 7 days, the state of attachment of the microchannel to the iron plate was confirmed.
Here, Sample Nos. 1 to 4 of Experimental Example 1 are configured only by the sealing material, and do not include metal or metal oxide.

FIG. 3 showing the results of Experimental Example 1 circulates liquefied carbon dioxide through the microchannel, and the microchannel surface temperature when the surface temperature of the microchannel and the temperature of the back surface of the iron plate are lowered to the cooling temperature (-30 to −40 ° C.). The temperature difference between the surface temperature and the temperature of the iron plate back is shown. The smaller this temperature difference, the better the thermal conductivity.
In FIG. 3, the polymer material (sample No. 3) has the minimum (0.96 ° C.) temperature difference between the surface temperature of the microchannel and the temperature of the back surface of the iron plate.
Regarding the silicone sealant (sample No. 1) and mortar (sample No. 2), the temperature differences are 3.76 ° C. and 3.15 ° C., respectively, and it can be seen that the thermal conductivities of samples No. 1 and No. 2 are good.
The heat dissipation sheet (Sample No. 4) had the largest temperature difference (6.36 ° C.). However, if the temperature difference is such a level, the sample No. 4 can be used in the pasting freezing method.
Since each of the sample Nos. 1 to 4 has a temperature difference between the surface temperature of the iron plate and the surface temperature of the microchannel of about 1 to 6 ° C., it can be used as a filling material used in the pasting freezing method according to Experimental Example 1. It has been found.

In addition, with respect to the state of attachment of the microchannel to the iron plate after the liquefied carbon dioxide gas was circulated for 7 days, the microchannel and the iron plate are sufficiently adhered to each other in the silicone sealant (sample No. 1) and the polymer material (sample No. 3). It was.
On the other hand, in the mortar (sample No. 2) and the heat radiating sheet (sample No. 4), the sample (filling material) was peeled off and a gap was generated between the microchannel and the iron plate. Accordingly, it has been found that mortar and heat-dissipating sheet are unsuitable as a filling material used in the pasting freezing method in terms of adhesion.

With regard to workability, a silicone sealant (sample No. 1) is packed between the presence / absence of an operation (mixing operation) for pre-kneading the sealing material before application and the presence of other fixing means for attaching the microchannel to the iron plate. When used as a material, no mixing work is required, and no other fixing means is required. Therefore, the silicone sealant (sample No. 1) has no problem in terms of workability.
The mortar (sample No. 2) and the polymer material (sample No. 3) require mixing work and other fixing means. The heat radiation sheet (sample No. 4) does not require mixing work, but it is necessary to use other fixing means in combination. Therefore, the mortar, the polymer material, and the heat dissipation sheet have a problem in terms of workability.
In Experimental Example 1, when the experimental results, thermal conductivity, adhesiveness (adhesiveness), workability and cost shown in FIG. 3 are comprehensively evaluated, a silicone sealant is optimal as a sealing material for the filling material. Was confirmed.

[Experimental example 2]
Experiments were conducted on the effect of adding aluminum oxide (alumina) microparticles to the sealing material, and the results are shown in FIG.
In Experimental Example 2, it was confirmed whether or not the thermal conductivity and workability of the filling material were improved when alumina was added.
In Experimental Example 2, a spacing material (sample No. 1) in which a predetermined amount of alumina fine particles was added to the silicone sealant and a spacing material (sample No. 2) in which no alumina was added only with the silicone sealant were prepared. The predetermined amount of alumina was 50-100 g of alumina with respect to 200 g of silicone sealant.
Samples No. 1 and No. 2 were each packed in a mold, placed in a freezer with a constant temperature, and the temperature change of the sample was confirmed with a thermocouple.

In FIG. 4 which shows the result of Experimental Example 2, as for thermal conductivity, sample No1 in which alumina is added to a silicone sealant has a rapid temperature decrease compared to sample No2 in which alumina is not added, and thermal conductivity. Was confirmed to be improved.
From the experimental results shown in FIG. 4, it was confirmed that the thermal conductivity was improved by adding alumina to the silicone sealant.
Although not clearly shown in FIG. 4, the microchannel was attached to the iron plate with a silicone sealant to which alumina was added, and the adhesion was confirmed. The microchannel was not peeled off from the iron plate even when a force was applied after 24 hours. From this, it was found that even when alumina was added, the adhesiveness and adhesive strength of the silicone sealant did not decrease.

In FIG. 5 showing an example of the application freezing method construction, a plurality of microchannels 1 are attached to the inner surface of the tunnel lining segment 10. Although not shown in FIG. 5, a filling material 2 is interposed between the inner surface of the segment 10 and the microchannel 1.
In FIG. 5, since the flat plate-like microchannel 1 is light and flexible, it can be easily attached according to the curvature of the inner surface of the segment 10.
A supply pipe 2A and a return pipe 2B are connected to the microchannel 1, the supply pipe 2A is connected to a supply system (a supply system from a ground-side refrigerator), and a return pipe 2B is connected to a return system (to a ground-side refrigerator). Connected to the return system).

In FIG. 5, the tunnel lining segment 10 which is a structure has frame-like protrusions 10A and 10B on the inner surface side. Therefore, in order to affix the microchannel 1 to the segment 10, it is necessary to affix it to the region surrounded by the protruding portions 10A and 10B, and extra labor is required. When a frozen tube is welded and pasted to a structure as in the prior art, if there are irregularities such as the protruding portions 10A and 10B, a great deal of labor is required for the welding operation.
As shown in FIG. 2, if the microchannel 1 (freezing tube) is attached to the inner surface of the segment 10 using the interlining material 2, the silicone sealant that is the composition of the interlining material 2 exhibits an adhesive action. The microchannel 1 can be easily and reliably attached to the area surrounded by the protrusions 10 </ b> A and 10 </ b> B on the inner surface of the segment 10.
Since alumina, which is the composition of the interlining material 2, has good thermal conductivity, when a refrigerant (for example, liquefied carbon dioxide) flows inside the micro refrigerant channel of the micro channel 1, the micro channel 1 is Heat exchange efficiently with the heat of the ground on the back side of the segment 10 (structure) pasted (opposite the microchannel 1), efficiently absorbing the geothermal heat, and freezing the ground efficiently I can do it.

FIG. 6 shows a modification of the illustrated embodiment.
When the microchannel 1 is attached to the structure 10, the interstices 2 are bonded between the microchannel 1 and the structure 10 in the same manner as shown in FIG. 2.
In the modification of FIG. 6, the microchannel 1 and the filling material 2 are covered with a heat insulating member 3 disposed outside the microchannel 1 (upper side in FIG. 6). The heat insulating member 3 is attached to the structure 10 while maintaining the state in which the microchannel 1 and the filling material 2 are covered. As the heat insulating member 3, rock wool or the like can be used.
According to the modification of FIG. 6, since the microchannel 1 and the interlining material 2 are surrounded by the heat insulating member 3, the microchannel 1 is generated by the cold heat held by the liquefied carbon dioxide gas (secondary refrigerant) flowing through the microchannel 1. The frost is prevented from being generated on the surface of the water, and the cold heat of the secondary refrigerant is not consumed to generate the frost, but is used to freeze the surrounding ground. Therefore, the freezing efficiency is further improved.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, in the illustrated embodiment, liquefied carbon dioxide gas is exemplified as the refrigerant, but other liquefied gas and brine can also be used as the refrigerant.
In the illustrated embodiment, a microchannel is used as the sticking cryotube, but the present invention can also be applied to a freezing method using other sticking cryotubes.

DESCRIPTION OF SYMBOLS 1 ... Microchannel 2 ... Spacing material 3 ... Heat insulation member 10 ... Structure

Claims (6)

In the pasting freezing method that freezes the ground on the back side of the structure to which the freezing pipe is pasted, and pastes the freezing pipe to the underground structure,
Using a filling material containing a metal, an oxide of the metal, a fine particle of any alloy of the metal as a main component, a sealing material, and having both thermal conductivity and adhesion, An affixing freezing method characterized in that a freezing tube is affixed to the structure.   The sticking / freezing method according to claim 1, wherein the sealing material is a silicone-based sealing material.   The pasting / freezing method according to claim 1, wherein the metal is aluminum and the oxide is aluminum oxide.   The sticking / freezing method according to claim 1, wherein the metal is copper and the oxide is copper oxide.   The sticking freezing method according to any one of claims 1 to 4, wherein the interstitial material retains adhesion between the freezing tube and the structure at a temperature ranging from room temperature to -50 ° C.   The sticking / freezing method according to any one of claims 1 to 5, wherein the interstitial material retains thermal conductivity at room temperature to -50 ° C after pasting.

Images