JP6277100B2 - Freezing wall construction method - Google Patents

Description

  The present invention relates to a method for constructing a frozen wall that traverses a cavity in which liquid is stored in the ground.

  Conventionally, in order to construct a wall body such as a non-permeable continuous wall in the ground, a plurality of frozen tubes with fins are excavated from the ground and a continuous frozen soil wall is constructed in the ground. There exists a method (for example, refer patent document 1).

  Further, the liquefied gas supply passage connected to the liquefied gas supply device and the liquefied gas recovery passage connected to the liquefied gas recovery device are connected to a predetermined depth below the groundwater level in the structure body of the underground structure. There is a method in which a cooler is disposed, a liquefied gas is supplied to the cooler, and air in the structure body is cooled to freeze the surrounding ground of the underground structure (for example, see Patent Document 2).

JP 2006-52604 A JP 2009-221727 A

  When the method described in Patent Document 1 is applied to a cavity where water stays, the water can be frozen. However, since water convects normally, even if a freezing pipe is placed in the water and the refrigerant is flowed, the cooled water around the freezing pipe flows from the freezing pipe periphery due to the convection generated by the temperature difference, and the efficiency It was difficult to form freezing walls well.

  In addition, the method described in Patent Document 2 freezes the ground around an existing small underground structure such as a manhole, and is difficult to apply to the case where a frozen wall is formed over a wide area in a cavity where water stays. Met.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for constructing a frozen wall that efficiently forms a frozen wall that crosses a cavity in which liquid is stored in the ground. is there.

  A first invention for achieving the above-described object is a method for constructing a frozen wall that traverses a cavity in which liquid is stored in the ground, and is a first method in which a hole is drilled so as to reach the cavity from the ground. Inserting a bag into the cavity through the hole, disposing the bag inside the cavity, and pumping a filler from the ground to the bag, Expanding the inside of the cavity part b, and flowing the refrigerant into the freezing pipe inserted into the inside of the cavity part through the first hole, so as to reach the cavity part from the ground. A step c in which ice blocks are introduced into the cavity through a second hole drilled in the vicinity; and the convection of the liquid is suppressed by allowing the ice blocks to stay locally in the vicinity of the bag. Forming a cooling region in the vicinity thereof, and comprising the step c and the step d Thus a freeze wall construction method, which comprises forming the bag near freezing wall frozen.

  By putting ice blocks into the cavity and allowing the ice blocks to stay locally in the vicinity of the bag body in which the freezing tube is inserted, the cooling region is formed near the bag body by suppressing the convection of the liquid, and the vicinity of the bag body is frozen. Thus, the freezing wall can be efficiently formed.

  In the first invention, for example, at least a part of the ice block includes a specific gravity adjusting material, and in the step d, the ice block is formed in the cavity by stacking the ice block in the depth direction in the vicinity of the bag body. And forming the cooling region in the vicinity of the bag. In this case, the specific gravity adjusting material is attached to at least a part of the surface of the ice block as necessary. Moreover, the specific gravity adjusting material may be embedded in at least some of the ice blocks. Furthermore, the specific gravity adjusting material is, for example, a deformable soft member.

  By using the ice block that the specific gravity adjusting material adheres to the surface or is embedded inside, the specific gravity of the ice block can be adjusted and stacked in the depth direction in the vicinity of the bag body to form the ice block weir in the cavity. If the specific gravity adjusting material is a deformable soft member, when there is a gap between the bags, the gap between the bags can be filled with the deformable soft member separated from the ice block.

  In the first invention, for example, in the step c, an ice lump charging tube having a tip portion reaching into the cavity is inserted into the second hole, and the ice lump is charged using the ice lump charging tube, The ice lump charging tube is flexible, and the ice lump charging direction is adjusted by the tip. Moreover, if necessary, an ice slurry mixed with ethanol is used as at least a part of the ice blocks.

  By using the ice lump charging tube whose tip portion reaches the inside of the cavity and the ice lump charging direction is adjusted by the tip portion, the ice lump can be charged in an appropriate direction. Moreover, if an ice slurry mixed with ethanol is used, a large amount of ice blocks can be easily charged.

  According to a second aspect of the present invention, there is provided a method for constructing a frozen wall that traverses a cavity in which liquid is stored in the ground, and the cavity is formed through a first hole that is drilled so as to reach the cavity from the ground. A step of disposing a bag body inside the hollow portion, disposing the bag body inside the hollow portion, and feeding a filler to the bag body from the ground to expand the bag body inside the hollow portion. Step b and a second hole drilled in the vicinity of the freezing tube so as to reach the hollow portion from the ground while flowing a refrigerant through the freezing tube inserted into the hollow portion through the first hole. Providing a bubble generation source at the bottom of the cavity through a hole; and forming a bubble curtain in the liquid storage area of the cavity by generating bubbles from the bubble generation source; A cooling region is formed in the vicinity of the bag body by suppressing liquid convection. Comprising a step d of the a step c and step d freeze wall construction method characterized by forming a freeze wall frozen near the bag by.

  If a bubble curtain is formed in the liquid storage area of the cavity by installing a bubble generation source at the bottom of the cavity and generating bubbles from the bubble generation source, the convection of the liquid is suppressed by the bubble curtain in the vicinity of the bag body. A cooling region can be formed and the vicinity of the bag can be frozen to form a freezing wall efficiently.

  In the second invention, for example, in the step c, the gas inlet pipe is inserted into the second hole, the lower end of the gas inlet pipe is brought into contact with the bottom of the cavity, and the bottom is In the step d, the gas is sent from the ground via the gas feed tube, and the bubble hole provided at the lower end of the gas feed tube is changed to the bubble generating source. To generate the bubbles.

  Displace the lower end of the gas inlet tube so that it crosses the bottom of the cavity in the width direction, and generate bubbles using the bubble hole provided at the lower end of the gas inlet tube as the bubble source. Then, the bubble curtain can be formed so as to cross the cavity.

  ADVANTAGE OF THE INVENTION According to this invention, the construction method of the frozen wall which forms efficiently the frozen wall which crosses the cavity where the liquid was stored in the ground can be provided.

The figure which shows the state which installed the bag body 7 in the hollow part 5 in the ground The figure which shows the state which flowed the refrigerant | coolant through the freezing pipe | tube 11. The figure which shows the state which installed the pipe 27 for ice lump addition The figure which shows the state which injected the ice block 31 into the liquid storage area 2 The figure which shows the example of the ice block 31 using a specific gravity adjustment material The figure which shows the state which injected the ice block 31 into the liquid storage area 2 The figure which shows the state which injected the ice block 31 into the liquid storage area 2 Figure showing the vicinity of the tip of another ice lump charging tube The figure which shows the state which installed the pipe 47 for gas delivery in the liquid storage area 2 The figure which shows the state which formed the bubble curtain 51 in the liquid storage area 2

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view showing a state in which a bag body 7 is installed in a hollow portion 5 in the ground. FIG. 1A is a view showing a state in which the bag body 7 is inserted into the excavation hole 3, and FIG. 1B is a view showing a state in which the bag body 7 is filled with a filler and expanded.

  As shown in FIG. 1, the underground hollow portion 5 is a tunnel covered with, for example, lining concrete 4. In the cavity 5, water is stored in the liquid storage area 2. In the step shown in FIG. 1A, in order to install the bag body 7 in the cavity 5, first, the excavation hole 3 that is the first hole is formed from the ground surface 1. At this time, the cylindrical guide member 13 is inserted into the excavation hole 3. When the excavation hole 3 reaches the upper outer surface of the cavity portion 5, the lower end of the guide member 13 inserted through the excavation hole 3 is joined to the upper outer surface of the cavity portion 5. For joining the guide member 13 and the cavity 5, for example, an adhesive, mortar, or other members are used. The upper end of the guide member 13 is set to be at least a position higher than the groundwater level.

  After the joining of the guide member 13 and the cavity portion 5 is completed, the excavation hole 3 is communicated with the cavity portion 5 through the upper wall portion of the cavity portion 5. In this embodiment, water is stored in the cavity 5, but as described above, since the lower end of the guide member 13 is joined to the outer surface of the cavity 5, the stored water level 15 inside the cavity 5 is Even if it rises, water does not flow out from the excavation hole 3 into the ground. In addition, since the upper end of the guide member 13 is set to be at least a position higher than the groundwater level, underground water in the ground does not flow into the hollow portion 5 or the guide member 13.

  Next, the freezing tube 11 and the bag body 7 are inserted into the excavation hole 3 (guide member 13). The bag body 7 is inserted into the cavity 5 in a folded state. The bag body 7 is, for example, a bag made of cloth or resin. The bag body 7 is inserted into the excavation hole 3 in a folded state (a reduced diameter state). Further, the height of the bag body 7 corresponds to the height inside the cavity 5.

  The bag body 7 is connected to a tube body (not shown) for pumping the filler. One tube body 7 may be connected to one tube body (not shown), or a plurality of bag bodies 7 may be connected. For example, the bag body 7 divided into a plurality in the height direction may be connected to a single pipe body (not shown).

  After inserting the bag body 7 into the excavation hole 3 as shown in FIG. 1A, the filler is pumped into the bag body 7 as shown in FIG. Fill. The bag body 7 is expanded in the cavity 5 by the filler. For example, the bag body 7 is expanded to a diameter larger than the diameter of the excavation hole 3. In addition, as a filler, although a normal grout material etc. can be used, a thing with high heat conductivity is desirable.

  FIG. 2 is a diagram illustrating a state in which a refrigerant is passed through the freezing tube 11. FIG. 2A is a vertical cross-sectional view in a state in which a refrigerant flows through the freezing tube 11, and FIGS. 2B and 2C are horizontal cross-sectional views in a state in which the refrigerant flows through the freezing tube 11. is there. 2B is a cross-sectional view taken along arrow A1-A1 shown in FIG. 2A, and FIG. 2C is a cross-sectional view taken along arrow A2-A2 shown in FIG.

  When the filling material is pumped and filled in the bag body 7 in the step shown in FIG. 1B, as shown in FIGS. 2B and 2C, the adjacent bag bodies 7 are connected to each other. It is desirable to adhere. In addition, it is desirable that the bag body 7 and the inner surface of the cavity 5 are brought into close contact with each other. By doing in this way, the underground wall 10 with high obstruction | occlusion property with respect to the cavity part 5 can be constructed | assembled.

  However, as illustrated in FIG. 2B, in the underground wall 10, a gap 61 may be formed between the bag bodies 7. In addition, a gap may be formed between the bag body 7 and the inner surface of the hollow portion 5 or the like. Further, as shown in FIG. 2C, the underground wall 10 may be provided with an opening 63 for placing an obstacle such as a pipe or a rack.

  As shown in FIG. 2B and FIG. 2C, the bag body 7 has a through-hole 17 in the approximate center. That is, the bag body 7 has a substantially donut shape. The freezing tube 11 is provided so as to penetrate the penetration part 17 of the bag body 7. For this reason, the bag body 7 expands at the outer peripheral portion of the freezing tube 11. That is, the freezing tube 11 is not exposed to the outside in the range where the bag body 7 is disposed. The freezing tube 11 is a double tube, for example, and can flow a refrigerant therein.

  In the step shown in FIG. 1 (b), the bag body 7 is filled with a filler and inflated, and then, as shown in FIG. 2, the refrigerant is caused to flow through the freezing tube 11 inserted into the penetrating portion 17. The refrigerant is set to a temperature below the freezing point of water. For this reason, the periphery of the freezing tube 11 is frozen. For example, in the range below the groundwater level, the groundwater solidifies and becomes frozen soil 19. Further, in the cavity 5, the water around the bag body 7 is frozen and becomes a frozen part 21.

  At this time, in the liquid storage area 2, the cooled water has a higher specific gravity and flows vertically downward. As a countercurrent, in the vicinity of the surface of the stored water level 15, uncooled warm water flows in the direction of the freezing pipe 11, and a vertical circulation flow is generated. As a result, the cold input from the freezing tube 11 to the region to be frozen is taken out of the region by the transfer of the cold due to the flow before being used for sensible heat and latent heat. Will be brought.

  Since the vertical circulation flow as described above is generated, as shown in FIGS. 2A and 2B, the frozen portion 21 is not sufficiently formed in the vicinity of the stored water level 15, and the surface 41 of the bag body 7 is May be exposed. In addition, when there is a gap 61 in the underground wall 10 as shown in FIG. 2B, or when an opening 63 is provided in the underground wall 10 as shown in FIG. Depending on the case, the surroundings of the gap 61 and the opening 63 may be insufficiently frozen.

  FIG. 3 is a view showing a state in which the ice block introducing tube 27 is installed. In the process shown in FIG. 3, the excavation hole 9, which is the second hole, is drilled near the freezing pipe 11 so as to reach the cavity 5 from the ground surface 1. Then, the ice block introducing tube 27 in which the distal end portion 29 reaches the cavity portion 5 is inserted into the excavation hole 9. The upper end portion of the ice lump charging tube 27 is provided on the ground, and the hopper 30 is connected thereto. The ice lump charging tube 27 is made of a flexible material. The ice lump charging tube 27 can adjust the ice lump charging direction by the tip 29.

  FIG. 4 is a view showing a state where the ice block 31 is put into the liquid storage area 2. FIG. 4 is an enlarged view of the range C shown in FIG. In the process shown in FIG. 4, an appropriate amount of ice mass 31 is introduced into the hopper 30 on the ground so that a large amount of ice mass 31 can be smoothly introduced. Then, the ice block 31 is charged into the cavity 5 from the hopper 30 through the ice block charging tube 27. A heat insulating sheet or a lubricating sheet may be attached to the inner side surface of the hopper 30 in order to prevent freezing of ice and the like.

  It is assumed that the ice block 31 thrown into the cavity 5 is frozen fresh water. The ice block 31 has a size of several mm to several cm so as to have various surface areas. If the ice block 31 having a moderately distributed size is used, it functions well as a resistor for reducing the flow rate of water after being put into the cavity 5.

  Since the ice block 31 thrown into the cavity 5 has a specific gravity of about 0.9, the ice block 31 floats on the above-described circulation flow by floating on the water surface. And as shown in FIG. 4, it stays locally in the water surface vicinity of the bag body 7 vicinity. The ice block 31 that stays locally in the vicinity of the bag 7 serves as a resistor for reducing the flow velocity of the flow, and reduces the temperature difference (density difference) that causes heat convection.

  In the state shown in FIG. 4, convection of water in the vicinity of the bag body 7 is suppressed by the ice lump 31 that locally stays in the vicinity of the bag body 7, and the cooling region 35 is rapidly cooled in the vicinity of the bag body 7. Is formed, and a circulating flow is generated at a position away from the bag body 7 as indicated by an arrow D1. In the first embodiment, due to the action of the freezing pipe 11 and the cooling region 35, the freezing part 21 near the bag body 7 is enlarged and the freezing wall is formed even when the underground wall 10 has the gap 61 and the opening 63. It is formed.

  As described above, in the first embodiment, the ice block 31 is introduced into the cavity 5, and the ice block 31 is allowed to stay locally in the vicinity of the bag body 7 in which the freezing tube 11 is inserted, thereby suppressing water convection. Thus, a cooling region 35 is formed in the vicinity of the bag body 7. In the first embodiment, the ice block 31 that stays locally in the cooling region 35 is used as auxiliary cooling means for the freezing tube 11, so that the vicinity of the bag body 7 can be frozen to efficiently form a frozen wall. Can do. Since the melting latent heat of the ice block 31 is larger than the specific heat of water, covering the water surface around the freezing tube 11 in the vicinity of the bag body 7 with a large amount of ice block 31 increases the freezing speed and ensures the freezing deadline. It can be carried out.

  Next, a second embodiment will be described. In the second embodiment, the ice block 31 is put into the cavity 5 by the same method as in the first embodiment, but a specific gravity adjusting material is included in a part of the ice block 31. FIG. 5 is a diagram illustrating an example of the ice block 31 using the specific gravity adjusting material.

  5 (a) and 5 (b) are views showing the ice block 31a in which the specific gravity adjusting material 36 is embedded, and FIG. 5 (a) is a cross-sectional view taken along arrows EE shown in FIG. 5 (b). is there. As shown in FIGS. 5A and 5B, the ice block 31a has a specific gravity adjusting material 36 embedded therein. The ice block 31a has a prismatic shape, for example. The specific gravity adjusting material 36 is, for example, a granular material such as aggregate or gravel having a specific gravity larger than that of the ice block 31 frozen with fresh water.

  FIG.5 (c) is a figure which shows the ice lump 31b with which the specific gravity adjustment material 37 adhered to the surface. As shown in FIG.5 (c), the specific gravity adjusting material 37 has adhered to the surface of the ice lump 31b. The specific gravity adjusting material 37 is, for example, a granular material such as PVC, a rubber piece, or a wood chip having a specific gravity larger than that of the ice block 31 frozen with fresh water. In addition, the ice block in this invention is not limited only to what is mostly ice. For example, frozen soil (a product obtained by freezing soil containing water) manufactured in another place in advance can be crushed and used as an ice block. That is, the ice block in the present invention includes an object that is at least partially frozen. By crushing and using such frozen soil, it can be submerged in water, and a weir can be formed by the soil after melting.

  FIG. 6 is a diagram showing a state in which the ice block 31 is put into the liquid storage area 2. If the ice block 31a and the ice block 31b including the specific gravity adjusting material as shown in FIG. 5 are introduced, as shown in FIG. 6, a part of the ice block 31 having a specific gravity larger than that of water is near the bag body 7 in the depth direction. As a result, the ice block weir 33 is formed in the cavity 5. If the shape is a prismatic shape like the ice block 31a, the ice block weir 33 can be stacked more easily than when the ice block is spherical.

  The ice block weir 33 formed in the vicinity of the bag body 7 serves as a resistor for reducing the flow velocity of the flow, reduces the temperature difference (density difference) that causes heat convection, and suppresses the movement of cold heat. Become a layer. As a result, convection of water in the vicinity of the bag body 7 is suppressed, and a cooling region 35 that is rapidly cooled is formed in the vicinity of the bag body 7. In the cooling region 35, a flow as indicated by an arrow D <b> 2 shown in FIG. 6. Occurs. In the second embodiment, due to the action of the freezing pipe 11 and the cooling region 35, the freezing part 21 near the bag body 7 is enlarged and the freezing wall is formed even when the underground wall 10 has the gap 61 and the opening 63. It is formed.

  As described above, in the second embodiment, the ice block 31 is introduced into the cavity 5, and the ice block 31 including the specific gravity adjusting material is stacked in the water depth direction in the vicinity of the bag body 7 in which the freezing tube 11 is inserted. The weir 33 is formed, and the cooling region 35 is formed in the vicinity of the bag body 7 by suppressing the convection of water. In the second embodiment, by using the ice block weir 33 as an auxiliary cooling means for the freezing pipe 11 in the cooling region 35, the vicinity of the bag body 7 can be frozen and a freezing wall can be formed efficiently.

  Next, a third embodiment will be described. In the third embodiment, as in the second embodiment, the ice block 31 is put into the cavity 5 to form the ice block weir 33. The specific gravity adjusting material 36 and the ice block 31b embedded in the ice block 31a are formed. It is assumed that the specific gravity adjusting material 37 attached to the surface includes a deformable soft member. The deformable soft member is, for example, rubber or soft resin. Moreover, the pumping pump 39 (FIG. 7) shall be provided in the underground wall 10 on the opposite side to the ice block weir 33.

  FIG. 7 is a view showing a state in which the ice block 31 is put into the liquid storage area 2. The pumping pump 39 shown in FIG. 7 is operated continuously or intermittently, and a flow as shown by an arrow F occurs in the liquid storage area 2 while the pumping pump 39 is in operation. Then, due to the flow indicated by the arrow F, the specific gravity adjusting material 36 and the specific gravity adjusting material 37, which are deformable soft members melted from the ice blocks 31a and 31b, float on the surface 41 of the underground wall 10 on the ice block weir 33 side. Then, the gap 61 between the bags 7 is closed. When the gap 61 between the bag bodies 7 is closed, the flow of water from the cooling region 35 formed in the vicinity of the bag body 7 by the ice block weir 33 to the pumping pump 39 side of the underground wall 10 is prevented. Even when the inner wall 10 has the gap 61 and the opening 63, the frozen portion 21 in the vicinity of the bag body 7 is efficiently enlarged to form a frozen wall.

As described above, in the third embodiment, similarly to the second embodiment, the ice blocks 31 including the specific gravity adjusting material are stacked in the water depth direction to form the ice block weir 33, thereby suppressing the convection of water and the bag 7 A cooling region 35 is formed in the vicinity of. Further, the gap 61 between the bag bodies 7 is closed by the specific gravity adjusting material 36 and the specific gravity adjusting material 37 which are deformable soft members. Also in the third embodiment, by using the ice block weir 33 as an auxiliary cooling means for the freezing pipe 11 in the cooling region 35, the vicinity of the bag body 7 can be frozen and a freezing wall can be efficiently formed.
In the third embodiment, a powder that absorbs and expands water such as bentonite may be used as the specific gravity adjusting material 36 embedded in the ice lump 31a and the specific gravity adjusting material 37 attached to the surface of the ice lump 31b. Desirably, a swelling material such as bentonite is confined to adjust the specific gravity, and the ice mass 31 in which the specific gravity is distributed is put into the trench. As a result, the specific gravity adjusting material melted from the ice block 31 is vertically distributed in the water like a tracer, and after entering the gap 61 between the bags 7 of the underground wall 10 by the flow shown by the arrow F while floating, The gap 61 can be positively clogged by swelling.

  In the first and second embodiments, the ice block 31 is thrown into only one side of the underground wall 10, but it may be thrown into both sides of the underground wall 10 to form cooling regions on both sides. In the first to third embodiments, an ice slurry mixed with ethanol may be used as at least a part of ice blocks. If an ice slurry mixed with ethanol is used, a large amount of ice blocks can be charged easily.

  Although the ice lump charging tube 27 used in the first to third embodiments has flexibility and can adjust the charging direction of the ice lump 31 at the tip 29, the ice lump used for charging the ice lump 31 is used. The input tube is not limited to this.

  FIG. 8 is a view showing the vicinity of the tip of another ice lump charging tube. FIG. 8A shows the vicinity of the tip 29a of the ice lump charging tube 27a. As shown in FIG. 8A, a guide member 25 that guides the charging direction of the ice block 31 is provided at the tip 29a of the ice block input tube 27a. FIG. 8B shows the vicinity of the tip 29b of the ice lump charging tube 27b. As shown in FIG. 8 (b), the tip 29 b of the ice lump charging tube 27 b has a bottom 43, and a hole 45 is provided in the ice lump 31 charging direction. Even when these ice lump charging tubes are used, the ice lump 31 can be charged in an appropriate direction.

  Next, a fourth embodiment will be described. FIG. 9 is a view showing a state in which the gas inlet tube 47 is installed in the liquid storage area 2. FIG. 9A is a vertical sectional view in a state where the gas feeding pipe 47 is installed, and FIG. 9B is an enlarged sectional view in the vicinity of the gas feeding pipe 47. FIG.9 (b) is sectional drawing by the arrow GG shown to Fig.9 (a).

  In the fourth embodiment, first, similarly to the first embodiment, as shown in FIG. 9A, the excavation hole 3 which is the first hole is formed from the ground surface 1, and the excavation hole 3 is formed. The freezing tube 11 and the bag body 7 are inserted into the (guide member 13), and the bag body 7 is inserted into the cavity 5. Then, the filling material is pumped and filled into the bag body 7 through a tube body (not shown). The bag body 7 is expanded in the cavity 5 by the filler. Thereafter, the refrigerant is caused to flow through the freezing tube 11 inserted into the through portion 17 of the bag body 7. Thereby, for example, in the range below the groundwater level, the groundwater solidifies and becomes frozen soil 19. Further, in the cavity 5, the water around the bag body 7 is frozen and becomes a frozen part 21.

  As described in the first embodiment, in the liquid storage area 2, the specific gravity of the cooled water increases and flows vertically downward, and the warm water that is not cooled near the surface of the stored water level 15 is frozen tube 11. In this direction, a vertical circulation flow is generated. Therefore, the frozen portion 21 is not sufficiently formed in the vicinity of the stored water level 15, and the surface of the bag body 7 may be exposed. In addition, when there is a gap 61 in the underground wall 10 as shown in FIG. 2B, or when an opening 63 is provided in the underground wall 10 as shown in FIG. Depending on the case, the surroundings of the gap 61 and the opening 63 may be insufficiently frozen.

  In the step shown in FIG. 9A, as in the first embodiment, the excavation hole 9, which is the second hole, is drilled in the vicinity of the freezing pipe 11 so as to reach the cavity 5 from the ground surface 1. . Then, instead of the ice lump charging tube 27 of the first embodiment, the gas feeding tube 47 is inserted into the excavation hole 9. As shown in FIG. 9 (b), the gas inlet tube 47 is arranged with its lower end in contact with the bottom 55 of the cavity 5. Then, the lower end portion of the gas feeding pipe 47 is deformed so as to become a transverse portion 57 that crosses the bottom portion 55 of the cavity portion 5 in the width 53 direction. A bubble hole 59 as a bubble generation source is provided on the upper surface of the crossing portion 57.

  FIG. 10 is a diagram illustrating a state in which the bubble curtain 51 is formed in the liquid storage area 2. In the process shown in FIG. 10, gas is sent from the ground to the hollow portion 5 through the gas inlet tube 47, and the bubble hole 59 provided in the transverse portion 57 at the lower end of the gas inlet tube 47 is used as the bubble generation source. As a result, bubbles 49 are generated. A gas that does not adversely affect the surroundings, such as air or carbon dioxide, is used. A bubble curtain 51 is formed in the liquid storage area 2 of the cavity 5 by generating bubbles 49 from the bubble holes 59.

  The bubble curtain 51 shown in FIG. 10 serves as a resistor for reducing the flow velocity of the flow, and serves as a heat insulating layer that reduces the temperature difference (density difference) that causes heat convection and suppresses the movement of cold heat. As a result, convection of water in the vicinity of the bag body 7 is suppressed, and a cooling region 35a that is rapidly cooled in the vicinity of the bag body 7 is formed, as indicated by arrows H1 and H2 on both sides of the bubble curtain 51. Local circulation flow occurs. Further, due to the action of the freezing pipe 11 and the cooling region 35a, the freezing portion 21 near the bag body 7 is enlarged and a freezing wall is formed even when the underground wall 10 has the gap 61 and the opening 63.

  As described above, in the fourth embodiment, the bubble 49 is generated from the bubble generation source at the bottom 55 of the cavity 5 to form the bubble curtain 51, and the convection of water is suppressed to cool in the vicinity of the bag body 7. Region 35a is formed. In the fourth embodiment, the freezing heat of the freezing pipe 11 is not taken out, the cooling region 35a where heat is not brought about by the flow is formed, and the vicinity of the bag body 7 is frozen by reducing the region to be cooled. A freezing wall can be formed well.

  In the fourth embodiment, the bubble 49 is generated using the lower end portion of the gas inlet tube 47 as a bubble generation source, but the bubble generation source is not limited to this. For example, dry ice placed in a net can be installed on the bottom 55 of the cavity 5 through the excavation hole 9 and used as a gas generation source.

  Moreover, you may use combining formation of the bubble curtain 51 of 4th Embodiment, and injection | throwing-in of the ice block 31 of 1st-3rd Embodiment. In this case, after putting the ice block 31 into the cavity 5, the bubbles 49 are generated from the bubble generation source at the bottom 55 of the cavity 5 to form the bubble curtain 51, and the flow of water in the direction of the arrow H2 shown in FIG. As a result, the ice block 31 is moved to the vicinity of the bag body 7. By using the bubble curtain 51 and the ice block 31 in combination, the vicinity of the bag body 7 can be more efficiently frozen and a frozen wall can be formed.

  In the first to fourth embodiments, the bag body 7 and the freezing tube 11 are simultaneously inserted into the cavity portion 5. However, the bag body 7 is not necessarily inserted into the hollow portion 5 simultaneously with the freezing tube 11. . The freezing tube 11 may be inserted before the bag body 7 is inserted, or the freezing tube 11 may be inserted after the bag body 7 is inserted.

  In addition, the underground wall 10 is not limited to the one constructed with the plurality of bag bodies 7 provided, and the plurality of bag bodies 7 do not have to be provided as long as it can be constructed with one bag body 7. The underground wall may be formed by disposing a plurality or a single bag body 7 inside the cavity 5, and the number of the bag bodies 7 may be any number. The cross-sectional shape of the bag body 7 is not limited to a substantially circular shape (including the presence or absence of a through portion), and may be a polygonal shape or other shapes.

  Furthermore, the bag body 7 and the freezing pipe 11 do not have to be inserted into the same excavation hole 3. For example, a freezing tube insertion hole may be provided separately from the bag 7 and the excavation hole 3 into which a tube body (not shown) is inserted, and the freezing tube 11 may be inserted into the cavity 5 from the freezing tube insertion hole. Even in this case, the guide member 13 may be used as necessary. In this case, the number of the bags 7 and the freezing tubes 11 may be the same or different. In addition, since the effect of the wall body by the bag body 7 will become small if the bag body 7 and the freezing pipe | tube 11 are separated too much, it is desirable to provide the excavation hole 3a in the vicinity of the excavation hole 3 (bag body 7).

  In the first to fourth embodiments, the gap 61 between the bag bodies 7 shown in FIG. 2 (b), the gap between the bag body 7 and the inner surface of the cavity 5, and the opening 63 shown in FIG. 2 (c). A filling member (not shown) may be filled in a gap or the like after the obstacle has been installed. As the filling member, for example, a grout material or the like can be used. The filling member may be filled from the ground by newly forming an excavation hole (not shown) so as to communicate with the filling target portion. By doing in this way, even if there is an obstacle, the underground wall 10 can be constructed by the bag body 7 and the filling member 8.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

2 ......... Liquid storage area 3, 9 ......... Drilling hole 5 ......... Cavity 7 ......... Bag 10 ...... Underground wall 11 ......... Freezing pipe 19 ......... Frozen soil 21 ......... Freezing Portions 27, 27a, 27b ......... Icy block feeding tubes 29, 29a, 29b ......... Tips 31, 31a, 31b ...... Ice blocks 33 ...... Ice blocks weirs 35, 35a ......... Cooling zones 36, 37 ... …… Specific gravity adjusting material 39 ……… Pump pump 41 ……… Surface 47 ……… Gas feed pipe 49 ……… Bubble 51 ……… Bubble curtain 55 ……… Bottom 57 ……… Transverse section

Claims (9)

A method of constructing a frozen wall that crosses a cavity in which liquid is stored in the ground,
A step of inserting a bag into the cavity through a first hole drilled so as to reach the cavity from the ground, and disposing the bag in the cavity;
A step b in which a filler is pumped from the ground to the bag body, and the bag body is expanded inside the hollow portion;
Through the second hole drilled in the vicinity of the freezing tube so as to reach the hollow portion from the ground while flowing the refrigerant through the freezing tube inserted into the hollow portion through the first hole. A step c of introducing ice blocks into the cavity;
Forming a cooling region in the vicinity of the bag body by suppressing the convection of the liquid by allowing the ice block to stay locally in the vicinity of the bag body; and
Comprising
A method for constructing a frozen wall, wherein a frozen wall is formed by freezing the vicinity of the bag body in steps c and d. At least a portion of the ice mass contains a specific gravity adjusting material,
2. The step d), wherein the ice block is formed in the water depth direction in the vicinity of the bag body to form an ice block weir in the cavity, and the cooling region is formed in the vicinity of the bag body. Freezing wall construction method.   The method for constructing a frozen wall according to claim 2, wherein the specific gravity adjusting material is attached to at least a part of the surface of the ice block.   The method for constructing a frozen wall according to claim 2 or 3, wherein the specific gravity adjusting material is embedded in at least a part of the ice block.   The construction method of the frozen wall according to any one of claims 2 to 4, wherein the specific gravity adjusting material is a deformable soft member. In the step c, an ice lump charging tube whose tip reaches the inside of the cavity is inserted into the second hole, and the ice lump is charged using the ice lump charging tube,
6. The method for constructing a frozen wall according to claim 1, wherein the ice lump charging tube has flexibility, and the ice lump charging direction is adjusted by the tip portion.   The construction method of the frozen wall according to any one of claims 1 to 6, wherein an ice slurry mixed with ethanol is used as at least a part of the ice blocks. A method of constructing a frozen wall that crosses a cavity in which liquid is stored in the ground,
A step of inserting a bag into the cavity through a first hole drilled so as to reach the cavity from the ground, and disposing the bag in the cavity;
A step b in which a filler is pumped from the ground to the bag body, and the bag body is expanded inside the hollow portion;
Through the second hole drilled in the vicinity of the freezing tube so as to reach the hollow portion from the ground while flowing the refrigerant through the freezing tube inserted into the hollow portion through the first hole. Installing a bubble generating source at the bottom of the cavity, c.
Forming a bubble curtain in the liquid storage area of the cavity by generating bubbles from the bubble generation source, and forming a cooling area in the vicinity of the bag body by suppressing convection of the liquid by the bubble curtain; and ,
Comprising
A method for constructing a frozen wall, wherein a frozen wall is formed by freezing the vicinity of the bag body in steps c and d. In step c, the gas inlet tube is inserted into the second hole, and the lower end portion of the gas inlet tube is brought into contact with the bottom portion of the cavity portion so as to cross the bottom portion in the width direction. Let
In the step d, the gas is sent from the ground through the gas feeding pipe, and the bubbles are generated using the bubble hole provided at the lower end of the gas feeding pipe as the bubble generation source. The construction method of the frozen wall of Claim 8.

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