Cement milk injection method and cement milk injection device

Abstract

An object of the present invention is to provide a cement milk injection method and a cement milk injection device that can prevent corrosion of the first casing pipe. [Solution] The cement milk injection method involves injecting cement milk from the cement milk supply pipe 2 while substantially sealing the downward open side between the cement milk supply pipe 2 and the first casing pipe 1 with a first sealing means S1, and substantially sealing the upward open side between the second casing pipe 3 and the first casing pipe 1 with a second sealing means S1, to fill the cement milk on the outside of the first casing pipe 1.

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for injecting cement milk, and more particularly to a method and an apparatus for injecting cement milk that can prevent corrosion of a first casing pipe. [Background technology]

[0002] Conventionally, when drilling for hot springs, a borehole is excavated using a drilling machine, and after drilling, an outer pipe is buried in the borehole and an inner pipe is buried in the outer pipe. Cement milk is then supplied from the inner pipe and injected between the borehole and the outer pipe to solidify and protect the outer pipe (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 3-44623 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above construction method, the end between the borehole and the outer pipe is open and communicates with the outside air (see, for example, Figure 7 of Patent Document 1), and even if cement milk is injected between the borehole and the outer pipe, the injection pressure of the cement milk does not increase, and the cement mill does not reach the passage (aquifer) for the acidic groundwater flowing into the anti-wall, making it easy for the acidic groundwater to penetrate into the anti-wall, resulting in corrosion of the outer pipe.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a method and an apparatus for injecting cement milk, which have been made in consideration of the above problems. [Means for solving the problem]

[0006] The method for injecting cement milk according to claim 1 includes a first casing pipe disposed underground, a cement milk supply pipe disposed within the first casing pipe, and a second casing pipe disposed outside the first casing pipe and extending from the underground to the surface. 、 The cement milk supply pipe is provided with a first sealing means for substantially sealing a downward open side of the first casing pipe between the cement milk supply pipe and the first casing pipe, and a second sealing means for substantially sealing an upward open side of the second casing pipe between the second casing pipe and the first casing pipe, and the cement milk is injected from the cement milk supply pipe to fill the outside of the first casing pipe with the cement milk while the downward open side between the cement milk supply pipe and the first casing pipe is substantially sealed by the first sealing means, and the upward open side between the second casing pipe and the first casing pipe is substantially sealed by the second sealing means. The cement milk can be filled under high pressure not only in the area outside the first casing pipe but also in the underground waterway flowing into the area outside the first casing pipe. It is something.

[0007] In addition, the cement milk injection method described in claim 2 is the cement milk injection method described in claim 1, which includes a discharge pipe connected to a portion of the second casing pipe located above ground and discharging the cement milk between the first casing pipe and the second casing pipe to the outside air, and an operating unit for opening and closing a passage in the discharge pipe, and when the concentration of the cement milk discharged from the discharge pipe reaches a predetermined value, the operating unit is operated to close the passage in the discharge pipe.

[0008] In addition, the cement milk injection method described in claim 3 is the cement milk injection method described in claim 1, in which the second sealing means either fastens a second outer flange extending outward from the upper open end of the second casing pipe to a first outer flange extending outward from the upper open end of the first casing pipe, or interposes a sealing member between the first casing pipe and the second casing pipe.

[0009] In addition, the cement milk injection method described in claim 4 is the cement milk injection method described in claim 1, in which the first sealing means is a donut-shaped air-containing member (air packer) between the inner wall of the first casing pipe and the outer wall of the cement milk supply pipe opposite this inner wall.

[0010] The cement milk injection device according to claim 5 includes a first casing pipe disposed underground, a cement milk supply pipe disposed within the first casing pipe, a second casing pipe located outside the first casing pipe and extending from underground to above ground, and a first sealing means for substantially sealing a downward open side of the first casing pipe between the cement milk supply pipe and the first casing pipe. 、 and a second sealing means for substantially sealing an upper open side of the second casing pipe between the casing pipe and the first casing pipe, and the cement milk is injected from the cement milk supply pipe in a state in which the lower open side between the cement milk supply pipe and the first casing pipe is substantially sealed by the first sealing means, and the upper open side between the second casing pipe and the first casing pipe is substantially sealed by the second sealing means, thereby filling the cement milk on the outside of the first casing pipe. The cement milk can be filled under high pressure not only in the area outside the first casing pipe but also in the underground waterway flowing into the area outside the first casing pipe. It is something.

[0011] In addition, the cement milk injection device described in claim 6 is the cement milk injection device described in claim 5, which is provided with a discharge pipe connected to a portion of the second casing pipe located above ground and discharges the cement milk between the first casing pipe and the second casing pipe to the outside air, and an operating unit for opening and closing a passage in the discharge pipe, and when the concentration of the cement milk discharged from the discharge pipe reaches a predetermined value, the operating unit is operated to close the passage in the discharge pipe.

[0012] In addition, the cement milk injection device described in claim 7 is the cement milk injection device described in claim 5, in which the second sealing means either fastens a first outer flange extending outward from the upper open end of the second casing pipe to a first outer flange extending outward from the upper open end of the first casing pipe, or interposes a sealing member between the first casing pipe and the second casing pipe.

[0013] In addition, the cement milk injection device described in claim 8 is the cement milk injection device described in claim 5, in which the first sealing means is a donut-shaped air-containing member (air packer) between the inner wall of the first casing pipe and the outer wall of the cement milk supply pipe opposite this inner wall.

[0014] The method for injecting cement milk according to claim 9 is the method for injecting cement milk according to claim 2, in which, after injecting the cement milk, the cement milk is injected into the second casing pipe from the above-ground portion of the second casing pipe.

[0015] In addition, the cement milk injection method described in claim 10 is the cement milk injection method described in claim 2, in which after injecting the cement milk, the injection of cement milk from the above-ground portion of the second casing pipe into the second casing pipe is carried out by connecting the cement milk injection passage of the discharge pipe. Effect of the Invention

[0016] According to the method for injecting cement milk as described in claim 1, the first sealing means substantially seals the lower open side between the cement milk supply pipe and the first casing pipe, and the second sealing means substantially seals the upper open side between the second casing pipe and the first casing pipe, Cement milk is injected from the cement milk supply pipe to fill the outside of the first casing pipe with cement milk, so that the cement milk can be filled under high pressure not only into the area outside the first casing pipe, but also into the underground waterway flowing into the area outside the first casing pipe, thereby preventing corrosion of the first casing pipe due to strong acidic water, etc. flowing in through the underground waterway, and extending the life of the first casing pipe.

[0017] According to the cement milk injection method of claim 2, the above-mentioned In addition to the brightening effect, when the concentration of the cement milk discharged from the discharge pipe reaches a predetermined value, the operating part is operated to close the passage inside the discharge pipe, so that the concentration of the cement milk can be checked from the outside and the outside of the first casing pipe is solidified with cement of a predetermined concentration, thereby protecting the first casing pipe.

[0018] According to the method for injecting cement milk as set forth in claim 3, in addition to the effects of the invention as set forth in claim 1, the second sealing means fastens the first outer flange protruding outward from the upper open end of the second casing pipe to the first outer flange protruding outward from the upper open end of the first casing pipe, or Alternatively, a sealing member is interposed between the first casing pipe and the second casing pipe, so that the cement milk can be confined by simple means and put under high pressure, and filled not only in the area outside the first casing pipe, but also in underground waterways (e.g., cracks formed underground) flowing into the area outside the first casing pipe, thereby preventing corrosion of the first casing pipe due to strong acidic water, etc. flowing in through the underground waterway, and extending the life of the first casing pipe.

[0019] Furthermore, according to the cement milk injection method described in claim 4, in addition to the effects of the invention described in claim 1 above, the first sealing means is a donut-shaped air-containing member (air packer) that abuts against the inner wall of the first casing pipe and the outer wall of the cement milk supply pipe facing this inner wall, so that airtightness can be increased by simple means and backflow of cement milk to the ground can be prevented.After use, for example, air can be bled from the air supply passage (not shown) that supplies air from the ground to the air-containing member (air packer) and recovered when the cement milk supply pipe is pulled up, making post-processing easy.

[0020] According to the cement milk injection device of claim 5, the first sealing means substantially seals the lower open side between the cement milk supply pipe and the first casing pipe, and the second sealing means substantially seals the upper open side between the second casing pipe and the first casing pipe, Cement milk is injected from the cement milk supply pipe to fill the outside of the first casing pipe with cement milk, so that the cement milk can be filled under high pressure not only into the area outside the first casing pipe, but also into the underground waterway flowing into the area outside the first casing pipe, thereby preventing corrosion of the first casing pipe due to strong acidic water, etc. flowing in through the underground waterway, and extending the life of the first casing pipe.

[0021] Furthermore, according to the cement milk injection device described in claim 6, in addition to the effects of the invention described in claim 5 described above, when the concentration of the cement milk discharged from the discharge pipe reaches a predetermined value, the operating part is operated to close the passage in the discharge pipe, so that the concentration of the cement milk can be checked from the outside and the outside of the first casing pipe can be solidified with cement of a predetermined concentration to protect the first casing pipe.

[0022] According to the cement milk injection device of claim 7, in addition to the effect of the invention of claim 5, the second sealing means fastens the first outer flange protruding outward from the upper open end of the second casing pipe and the first outer flange protruding outward from the upper open end of the first casing pipe, or Alternatively, a sealing member is interposed between the first casing pipe and the second casing pipe, so that the cement milk can be confined by simple means and put under high pressure, and filled not only in the area outside the first casing pipe, but also in underground waterways (e.g., cracks formed underground) flowing into the area outside the first casing pipe, thereby preventing corrosion of the first casing pipe due to strong acidic water, etc. flowing in through the underground waterway, and extending the life of the first casing pipe.

[0023] Furthermore, according to the cement milk injection device described in claim 8, in addition to the effects of the invention described in claim 5 above, the first sealing means is a donut-shaped air-containing member (air packer) that abuts against the inner wall of the first casing pipe and the outer wall of the cement milk supply pipe facing this inner wall, so that airtightness can be increased by simple means and backflow of cement milk to the ground can be prevented.After use, for example, air can be bled from an air supply passage (not shown) that supplies air from the ground to the air-containing member (air packer) and recovered when the cement milk supply pipe is pulled up, making post-processing easy.

[0024] According to the method for injecting cement milk as set forth in claim 9, in addition to the effect of the invention as set forth in claim 2, after the cement milk is injected, the cement milk is pressurized and injected into the second casing pipe from the aboveground part of the second casing pipe, so that after the cement milk is injected, the cement milk filling the space between the first casing pipe and the second casing pipe settles and a void is generated at the top, and therefore it is possible to prevent corrosion of the first casing pipe due to strong acid water flowing in through the underground waterway by pressurizing and injecting the cement milk from a pipe (not shown) connected to the second casing pipe. If the degree of pressurization of the cement milk is increased, the cement milk can be filled deep into the underground waterway. Preferably, the concentration of the cement milk injected under pressure from a cement milk injection passage (not shown) connected to the second casing pipe is higher than the concentration of the cement milk injected from the cement milk supply pipe.

[0025] Furthermore, according to the method for injecting cement milk as set forth in claim 10, in addition to the effects of the invention as set forth in claim 2 described above, after the cement milk is injected, the cement milk is pressurized and injected into the second casing pipe from the above-ground part of the second casing pipe, so that after the cement milk is injected, the cement milk filling the space between the first casing pipe and the second casing pipe settles and fills the void that has formed at the top, thereby making it possible to prevent corrosion of the first casing pipe due to strong acidic water flowing in through an underground waterway, and after the cement milk is injected, the cement milk is injected into the second casing pipe from the above-ground part of the second casing pipe by connecting a cement milk injection passage (not shown) connected to a discharge pipe, so that the discharge pipe can be used effectively. Preferably, the concentration of the cement milk injected under pressure from a cement milk injection passage (not shown) connected to the discharge pipe is higher than the concentration of the cement milk injected from the cement milk supply pipe. [Brief description of the drawings]

[0026] [Figure 1]FIG. 1 is a schematic diagram of a cement milk injection device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of another embodiment of the cement milk injection device different from that of FIG. [Diagram 3] FIG. 3 is a schematic diagram of another embodiment of the cement milk injection device different from that of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] A cement milk injection method and cement milk injection device according to one embodiment of the present invention will be described with reference to Figs.

[0028] M shown in Figure 1 is a cement milk injection device used when drilling hot springs, geothermal energy, wells, etc., and the cement milk injection device M comprises a first casing pipe 1 placed underground, a cement milk supply pipe 2 placed within this first casing pipe 1, a second casing pipe 3 located outside the first casing pipe 1 and extending from the underground to the ground, a first sealing means S1 that approximately seals the downward open side of the first casing pipe 1 between the cement milk supply pipe 2 and the first casing pipe 1, and a second sealing means S2 that approximately seals the upward open side of the second casing pipe 3 between the second casing pipe 3 and the first casing pipe 1.

[0029] The first casing pipe 1 is excavated by a rotary excavator (not shown), and when excavation of a certain section is completed, the first casing pipe 1 (for example, a steel pipe) is placed in that section. A first casing pipe 1 and a cement milk supply pipe 2 are installed apart (floating) from the bottom of a borehole 10. Reference numeral 20 shown in FIG. 1 denotes a concrete foundation.

[0030] With the downward open side between the cement milk supply pipe 2 and the first casing pipe 1 substantially sealed by the first sealing means S1, and with the upward open side between the second casing pipe 3 and the first casing pipe 1 substantially sealed by the second sealing means S2, cement milk is injected from the cement milk supply pipe 2 to fill the outside of the first casing pipe 1 with the cement milk (cement milk injection method). The cement milk is pressurized to 1013 hPa or more, and the higher the pressure, the deeper the cement milk can be filled into the underground waterway communicating with the borehole 10.

[0031] Therefore, according to the above-mentioned cement milk injection device M (cement milk injection method), in particular, the second sealing means S2 makes it possible to fill not only the area outside the first casing pipe 1 with the cement milk outlet blocked (high pressure state), but also the underground waterways 4, 5 flowing into the area outside the first casing pipe 1, thereby preventing corrosion of the first casing pipe 1 due to strong acidic water, etc. flowing in through the underground waterways 4, 5, and extending the life of the first casing pipe.

[0032] Also, reference numeral 6 in Figure 1 denotes a discharge pipe that is connected to the portion of the second casing pipe 3 located above ground and discharges the fluid (mainly cement milk) between the first casing pipe 1 and the second casing pipe 3 to the outside air, and reference numeral 7 denotes an operating part that opens and closes the passage inside the discharge pipe 6.

[0033] Therefore, when cement milk is injected from the cement milk supply pipe 2 with the downward open side between the cement milk supply pipe 2 and the first casing pipe 1 approximately sealed by the first sealing means S1, and the upward open side between the second casing pipe 3 and the first casing pipe 1 approximately sealed by the second sealing means S2, the concentration of the cement milk discharged from the discharge pipe 6 gradually increases, and when the concentration reaches a predetermined value, the operating unit 7 is operated to close the passage in the discharge pipe 6, so that the concentration of the cement milk can be confirmed from the outside, and the outside of the first casing pipe 1 is solidified with cement of a predetermined concentration, thereby protecting the first casing pipe 1. In addition, if solid materials such as crushed hemp rope, bentonite, slime, etc. are mixed into the cement milk injected from the cement milk supply pipe 2, it is effective in sealing the underground waterways 4, 5 flowing into the area outside the first casing pipe 1.

[0034] The first sealing means S1 described above is located between the inner wall of the first casing pipe 1 and the outer wall of the cement milk supply pipe 2 facing this inner wall, and specifically, may be a concrete packing. In the case of the concrete packing shown in Fig. 1, the first casing pipe 1 with the concrete packing that abuts against the outer wall of the cement milk supply pipe 2 is prepared in advance, and the first casing pipe 1 with the concrete packing that abuts against the outer wall of the cement milk supply pipe 2 is guided into the excavated vertical hole and arranged as shown in Fig. 1. 8 in Fig. 1 is a hemp rope. After placement, cement milk is injected from the tip of the cement milk supply pipe 2 to fill the outside of the first casing pipe 1 with a predetermined amount of cement milk, which is then destroyed by an excavator not shown in the next excavation process.

[0035] In addition, the first sealing means S1 is preferably a doughnut-shaped air-containing member (air packer) that abuts against the inner wall of the first casing pipe 1 and the outer wall of the cement milk supply pipe 2 facing the inner wall, as shown in FIG. 2. After use, for example, air is removed from an air supply passage (not shown) that supplies air from the ground to the air-containing member (air packer) and can be collected when the cement milk supply pipe 2 is lifted, making post-processing easy. In addition, as shown in FIG. 3, when a concrete packing is used, a hemp rope 8 or the like is wound around the lower part of the reducing socket of the cement milk supply pipe 2, and the hemp rope 8 and the concrete packing are brought into contact with each other to increase airtightness and prevent backflow of cement milk. Therefore, it is possible to increase airtightness and prevent backflow of cement milk to the ground by a simple means, and at the same time, it is possible to remove air from an air supply passage (not shown) that supplies air from the ground to the air-containing member (air packer) and can be collected when the cement milk supply pipe 2 is lifted, making post-processing easy. In more detail, an air-containing member (air packer) is wrapped around the end of the cement milk supply pipe 2, and the air-containing member (air packer) is fixed at regular intervals every time the cement milk supply pipe 2 is extended, lowered to the desired position and fixed, and air is sent from the ground to inflate it into a doughnut shape to prevent backflow of cement milk. When the injection work is completed, the air is removed on the ground, and the air-containing member (air packer) is collected together with the removal of the cement milk supply pipe 2. In addition, when a concrete packing is used instead of the air-containing member (air packer) as shown in Figure 3, a hemp rope 8 or the like is wrapped around the lower part of the reducing socket to increase airtightness and prevent backflow of cement milk. When the concrete packing method is selected, a guide ring is fixed at the required interval so that the cement milk supply pipe 2 can be securely inserted into the hole machined in the concrete packing, and the cement milk supply pipe 2 does not swing. In addition, reference numeral 21 in FIG. 2 denotes a guide ring that guides the cement milk supply pipe 2 to the center of the cement milk supply pipe 1, and reference numeral 22 denotes a reducing socket.

[0036] The second sealing means S2 is formed by fastening the second outer flange 31 protruding outward from the upper open end of the second casing pipe 3 to the first outer flange 11 protruding outward from the upper open end of the first casing pipe 1 (fastening is performed by a bolt 9, a nut (not shown) screwed onto the bolt 9, welding, etc.), or Alternatively, a sealing member (not shown) is interposed between the first casing pipe 1 and the second casing pipe 3 .

[0037] The above-mentioned second sealing means S2 allows cement milk to be filled under high pressure not only into the area outside the first casing pipe 1, but also into the underground waterways 4, 5 flowing into the area outside the first casing pipe 1, thereby preventing corrosion of the first casing pipe 1 due to strong acidic water flowing in through the underground waterways 4, 5, and extending the life of the first casing pipe 1.

[0038] After the cement milk is injected, the cement milk filling the space between the first casing pipe 1 and the second casing pipe 3 settles, creating a void at the top. The first casing pipe 1 is corroded by strong acidic water flowing into this void through the underground waterways 4 and 5. To prevent this, after the cement milk is injected, the cement milk is pressurized and injected into the second casing pipe 3 from the above-ground part of the second casing pipe 3. The injection method is to connect a cement milk injection passage (not shown) to the discharge pipe 6. That is, by connecting a cement milk injection passage (not shown) to the discharge pipe 6, the discharge pipe 6 can be utilized effectively. It is preferable that the concentration of the cement milk injected under pressure from the cement milk injection passage (not shown) connected to the discharge pipe 6 is higher than the concentration of the cement milk injected from the cement milk supply pipe. This is because if the cement milk is pressurized to a higher degree, it can be filled deep into the underground waterway.

[0039] The means of injection is not limited to the above-mentioned embodiment, and instead of the discharge pipe 6, a dedicated cement milk injection passage (not shown) may be connected to the above-ground portion of the second casing pipe 3, and the injection may be performed by connecting this dedicated cement milk injection passage (not shown). Also, as described above, it is preferable that the concentration of the cement milk injected under pressure from the cement milk injection passage (not shown) connected to the second casing pipe 3 is higher than the concentration of the cement milk injected from the cement milk supply pipe 2. This is because if the degree of pressurization of the cement milk is increased, the cement milk can be filled deep into the underground waterway. [Explanation of symbols]

[0040] M Cement milk injection device S1 First sealing means S2 Second sealing means 1 First casing pipe 11 First outer flange 2. Cement milk supply pipe 3 Second casing pipe 31 Second outer flange 4 Underground waterway 5 Underground waterway 6. Exhaust pipe 7 Control section 8 Hemp Rope 9 Volts 10 Borehole 20 Concrete Foundation

Claims

1. a first casing pipe disposed underground; a cement milk supply pipe disposed within the first casing pipe; A second casing pipe is located outside the first casing pipe and extends from underground to above ground; a first sealing means for substantially sealing a downward open side of the first casing pipe between the cement milk supply pipe and the first casing pipe; a second sealing means for substantially sealing an upper open side of the second casing pipe between the second casing pipe and the first casing pipe, a first sealing means for sealing a lower open side between the cement milk supply pipe and the first casing pipe, and a second sealing means for sealing an upper open side between the second casing pipe and the first casing pipe, The cement milk is injected from the cement milk supply pipe to fill the outside of the first casing pipe with the cement milk, and the cement milk can be filled under high pressure not only in the area outside the first casing pipe but also in an underground waterway flowing into the area outside the first casing pipe. A method for injecting cement milk.

2. a discharge pipe connected to a portion of the second casing pipe located above ground and discharging the cement milk between the first casing pipe and the second casing pipe to the outside air; and an operating portion for opening and closing a passage in the exhaust pipe, When the concentration of the cement milk discharged from the discharge pipe reaches a predetermined value, the operating part is operated to close the passage in the discharge pipe.

2. The method for injecting cement milk according to claim 1 .

3. The second sealing means is a second outer flange protruding outward from the upper open end of the second casing pipe and a first outer flange protruding outward from the upper open end of the first casing pipe, or Or, a sealing member is interposed between the first casing pipe and the second casing pipe.

2. The method for injecting cement milk according to claim 1 .

4. The first sealing means is a doughnut-shaped air-containing member (air packer) that contacts the inner wall of the first casing pipe and the outer wall of the cement milk supply pipe facing the inner wall.

2. The method for injecting cement milk according to claim 1 .

5. a first casing pipe disposed underground; a cement milk supply pipe disposed within the first casing pipe; A second casing pipe is located outside the first casing pipe and extends from underground to above ground; a first sealing means for substantially sealing a downward open side of the first casing pipe between the cement milk supply pipe and the first casing pipe; a second sealing means for substantially sealing an upper open side of the second casing pipe between the second casing pipe and the first casing pipe, a first sealing means for sealing a lower open side between the cement milk supply pipe and the first casing pipe, and a second sealing means for sealing an upper open side between the second casing pipe and the first casing pipe, The cement milk is injected from the cement milk supply pipe to fill the outside of the first casing pipe with the cement milk, and the cement milk can be filled under high pressure not only in the area outside the first casing pipe but also in an underground waterway flowing into the area outside the first casing pipe. A cement milk injection device characterized by the above.

6. a discharge pipe connected to a portion of the second casing pipe located above ground and discharging the cement milk between the first casing pipe and the second casing pipe to the outside air; and an operating portion for opening and closing a passage in the exhaust pipe, When the concentration of the cement milk discharged from the discharge pipe reaches a predetermined value, the operating part is operated to close the passage in the discharge pipe.

6. The cement milk injection device according to claim 5.

7. The second sealing means is a second outer flange protruding outward from the upper open end of the second casing pipe and a first outer flange protruding outward from the upper open end of the first casing pipe, or Or, a sealing member is interposed between the first casing pipe and the second casing pipe.

6. The cement milk injection device according to claim 5.

8. The first sealing means is a doughnut-shaped air-containing member (air packer) that contacts the inner wall of the first casing pipe and the outer wall of the cement milk supply pipe facing the inner wall.

6. The cement milk injection device according to claim 5.

9. After the cement milk is injected, the cement milk is injected into the second casing pipe from the above-ground portion of the second casing pipe.

3. The method for injecting cement milk according to claim 2.

10. After the cement milk is injected, the cement milk is injected into the second casing pipe from the above-ground portion of the second casing pipe by connecting the cement milk injection passage of the discharge pipe.

3. The method for injecting cement milk according to claim 2.

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