Water-resisting layer plugging device and method adopting casing grouting method

Abstract

The invention discloses a casing grouting method water-resisting layer plugging device and method. The device comprises a plugging mechanism and a lifting mechanism. The plugging mechanism comprises a grouting cylinder, an extrusion reaming assembly, an extrusion assembly and a grouting assembly. The extrusion reaming assembly comprises an expansion air bag and an air injection assembly, and the expansion air bag sleeves the outer side wall of the grouting barrel; the extrusion assembly comprises a piston and an extrusion driving part; the grouting assembly is communicated with the feeding hole; the lifting mechanism is used for enabling the grouting barrel to ascend and descend in the drill hole. Soil around a drilled hole is extruded through an expansion air bag in the extrusion reaming assembly, and the hole diameter of the drilled hole is expanded. The larger hole diameter provides a space for pouring more cement paste, so that the thickness of a finally formed waterproof cement sheath is increased, loose soil on the inner wall of a drilled hole is compacted, the hole diameter is enlarged, a regular and flat hole wall interface is formed, the subsequently injected cement paste is tightly attached to the hole wall, circulation of underground water of the upper layer and the lower layer can be more effectively blocked, and the service life is prolonged. The waterproof effect is obviously improved.

Description

Technical Field

[0001] The present application relates to the technical field of water-blocking layer plugging, and in particular to a device and method for water-blocking layer plugging using a casing grouting method. Background Art

[0002] When conducting hydrogeological surveys and exploration work at a construction site, if there are multiple layers of groundwater on the site, accurately measuring and collecting groundwater in each layer and ensuring its independence become key tasks. However, in the actual engineering process, effectively isolating two layers of groundwater has always been a difficult engineering problem. When the groundwater aquifer is penetrated during drilling, it is often difficult to achieve effective blocking, causing the groundwater in the upper permeable layer to mix into the lower groundwater along the gap between the detection drill rod and the soil. This situation will cause errors and adverse effects on site hydrological research, water sample collection, and data collection. Therefore, it is particularly important to effectively block the aquifer between the two permeable layers to minimize the mutual influence of the upper and lower groundwater layers.

[0003] Currently, cement grouting is the conventional method for sealing aquicludes. This method involves injecting cement slurry into a borehole, relying on the solid barrier formed by the cement solidifying to achieve sealing. However, because the soil along the borehole's inner wall is typically loose, the contact surface between the cement sheath formed after grouting and the soil along the borehole's inner wall is uneven. This compromises the bond between the cement sheath and the soil, reducing the sealing effect. Summary of the Invention

[0004] In order to solve the technical problems in the prior art, the present application provides a device and method for sealing a water-insulating layer using a casing grouting method.

[0005] The present application provides a casing grouting method for sealing a water barrier layer and a method thereof, which adopts the following technical solutions: A casing grouting method water-insulating layer blocking device, comprising a blocking mechanism and a lifting mechanism; The sealing mechanism includes a grouting barrel, an extrusion and reaming assembly, an extrusion assembly and a grouting assembly. The grouting barrel is used to be inserted into the drilled hole, and its lower end is closed, and a plurality of grouting holes are opened on the outer side wall of the lower end; the extrusion and reaming assembly includes an expansion airbag and an air injection assembly, the expansion airbag is sleeved on the outer side wall of the grouting barrel, and the air injection assembly is connected with the air injection port of the expansion airbag, so as to expand or contract the expansion airbag; the extrusion assembly includes a piston and an extrusion driving member, the piston is sealingly and slidably arranged in the grouting barrel, a feed port is opened on the piston, a feed valve is provided on the feed port, and the output end of the extrusion driving member is connected with the piston, so as to drive the piston to move up and down; the grouting assembly is connected with the feed port; The lifting mechanism is connected to the grouting barrel and is used to lift the grouting barrel in the drill hole.

[0006] Preferably, the lifting mechanism includes a plurality of casings and static probes that are detachably connected end to end, the grouting cylinder is installed at the lower end of the lowest casing, and the static probe is connected to the casing assembly to drive the casing assembly to rise and fall.

[0007] Preferably, two adjacent sleeves are threadedly connected.

[0008] Preferably, an installation groove is formed on the outer side wall of the grouting cylinder, and the expansion airbag is located in the installation groove.

[0009] Preferably, a fixed block is fixed in the grouting barrel, and a guide hole, a first through hole and a second through hole are provided on the fixed block; the air injection assembly includes an air injection pipe and an air injection pump, one end of the air injection pipe is connected to the air injection port of the expansion airbag, and the other end passes through the first through hole and is detachably connected to the air injection pump.

[0010] Preferably, the extrusion drive member includes an extrusion drive electric rod, the fixed end of the extrusion drive electric rod is fixed in the grouting barrel, and the output end passes through the guide hole and is fixedly connected to the piston.

[0011] Preferably, a control component is further included, which is communicatively connected to the extrusion drive electric rod and the lifting mechanism, and is used to obtain the extension rate of the output shaft of the extrusion drive electric rod, and control the rising speed of the lifting mechanism according to the extension rate of the output shaft of the extrusion drive electric rod.

[0012] Preferably, the grouting assembly includes a grouting pipe, a grouting pump and a slurry tank, one end of the grouting pipe is connected to the feed port, and the other end is detachably connected to the outlet of the grouting pump after passing through the second through hole, and the inlet of the grouting pump is connected to the slurry tank.

[0013] Preferably, it further comprises a drill bit, which is detachably fixed to the lower end of the grouting cylinder.

[0014] The present application also provides a casing grouting method for sealing a water barrier layer, which is applicable to the casing grouting method for sealing a water barrier layer, and comprises the following steps: S1, assembling the device, lowering the grouting cylinder into the drill hole through the lifting mechanism; S2, when the grouting hole of the grouting barrel reaches the lowermost end of the drilling section that needs grouting and sealing, the grouting barrel stops descending; S3, injecting air into the expansion airbag through the air injection assembly to expand it and squeeze the surrounding soil to enlarge the borehole diameter; after squeezing, the expansion airbag is deflated, and the lifting mechanism drives the grouting barrel to rise to the height of the expansion airbag, repeating the cycle of air injection-squeezing-deflation-raising to perform overall squeezing and expanding of the target borehole section; S4. The lifting mechanism drives the grouting barrel to descend to the lowest end of the target drilling section, opens the feed valve, and injects cement slurry into the grouting barrel through the grouting assembly. After closing the feed valve, the extrusion drive member drives the piston to descend, and presses the cement slurry out of the grouting hole into the expanded borehole; if the piston reaches the lowest stroke, the feed valve is opened to replenish material. During the grouting process, the lifting mechanism continues to rise to complete the overall cement slurry pouring of the target drilling section.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. The expansion bladder in the extrusion reaming assembly squeezes the soil around the borehole, expanding the borehole diameter. The larger borehole diameter allows for more grout to be injected, increasing the thickness of the resulting water-blocking cement sheath, effectively blocking the flow of groundwater between the upper and lower layers and significantly improving water-blocking effectiveness. The expansion bladder pre-expands the borehole, compacting the loose soil on the borehole wall and expanding the borehole diameter, creating a regular, smooth interface. This allows the subsequently injected grout to adhere tightly to the borehole wall, eliminating the gaps caused by rough borehole walls in traditional methods. Furthermore, the piston and extrusion drive in the extrusion assembly work in conjunction with the grouting assembly. The extrusion drive drives the piston downward, forcing the grouting barrel and out of the grouting hole. This method increases the pressure of the ejected grout, ensuring that the grout more fully fills the expanded borehole space and reduces the occurrence of hollowing in the injected grout. This denser grout fill effectively improves the sealing reliability and further ensures the sealing effect of the water-blocking layer.

[0016] 2. By monitoring the extension rate of the extrusion drive's output shaft, the control unit can determine in real time the speed at which the cement slurry is extruded from the grouting hole. Based on this information, the control unit adjusts the lifting mechanism's ascending speed accordingly, aligning the grouting speed with the grouting barrel's ascending speed. For example, if the extrusion drive's output shaft rapidly pushes out the piston, causing the cement slurry to be extruded at a high rate, the control unit accelerates the lifting mechanism's ascending speed, ensuring a relatively uniform amount of cement slurry injected at different heights per unit time, thereby improving the uniformity of the resulting cement ring thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of a waterproof layer plugging device using a casing grouting method provided in one embodiment of the present application; Figure 2 yes Figure 1 A partial enlarged view of the middle area A; Figure 3 yes Figure 1 A partial enlarged view of the middle area B; Figure 4 This is a schematic diagram of the blocking principle of the waterproof layer blocking device using the casing grouting method in this application; Explanation of the accompanying drawings: 1. Sealing mechanism; 11. Grouting cylinder; 111. Grouting hole; 112. Fixing block; 1121. Guide hole; 1122. First through hole; 1123. Second through hole; 12. Extrusion and expansion assembly; 121. Expansion air bag; 122. Air injection assembly; 1221. Air injection pipe; 1222. Air injection pump; 13. Extrusion assembly; 131. Piston; 1311. Feed port; 1312. Feed valve; 132. Extrusion drive; 14. Grouting assembly; 141. Grouting pipe; 142. Grouting pump; 143. Slurry tank; 2. Lifting mechanism; 21. Casing; 22. Static penetration machine; 3. Drill bit; 100. Upper aquifer; 200. Lower aquifer; 300. Water-proof layer; 400. Water-proof cement ring. DETAILED DESCRIPTION

[0018] The following is combined with Figures 1-4 This application is described in further detail.

[0019] The embodiment of the present application discloses a casing grouting method water-insulating layer plugging device. Figure 1 The casing grouting method waterproof layer sealing device includes a sealing mechanism 1 and a lifting mechanism 2.

[0020] The plugging mechanism 1 includes a grouting cylinder 11, an extrusion and reaming assembly 12, an extrusion assembly 13 and a grouting assembly 14. The grouting cylinder 11 is used to be inserted into the drilled hole, and its lower end is closed. A plurality of grouting holes 111 are opened on the outer side wall of the lower end; the extrusion and reaming assembly 12 includes an expansion airbag 121 and an air injection assembly 122. The expansion airbag 121 is sleeved on the outer side wall of the grouting cylinder 11, and the air injection assembly 122 is connected to the air injection port of the expansion airbag 121 for expanding the expansion airbag. The airbag 121 expands or contracts; the extrusion assembly 13 includes a piston 131 and an extrusion drive member 132, the piston 131 is sealingly and slidingly arranged in the grouting cylinder 11, the piston 131 is provided with a feed port 1311, and the feed port 1311 is provided with a feed valve 1312, the output end of the extrusion drive member 132 is connected to the piston 131, and is used to drive the piston 131 to move up and down; the grouting assembly 14 is connected to the feed port 1311.

[0021] The lifting mechanism 2 is connected to the grouting cylinder 11 and is used to lift the grouting cylinder 11 in the drill hole.

[0022] When in use, the device is assembled, and the grouting cylinder 11 is lowered into the borehole through the lifting mechanism 2; when the grouting hole 111 of the grouting cylinder 11 reaches the lowermost end of the borehole section that needs grouting and sealing, the descent is stopped; the expansion airbag 121 is injected with air through the air injection component 122 to expand and squeeze the surrounding soil to enlarge the borehole diameter, and the expansion airbag 121 is deflated after squeezing, and the lifting mechanism 2 drives the grouting cylinder 11 to rise to the height of the expansion airbag 121, and the cycle of air injection-squeezing-deflation-rising is repeated to adjust the target borehole section. The lifting mechanism 2 drives the grouting barrel 11 to descend to the lowest end of the target drilling section, opens the feed valve 1312, and injects cement slurry into the grouting barrel 11 through the grouting assembly 14. After closing the feed valve 1312, the extrusion drive 132 drives the piston 131 to descend, and presses the cement slurry from the grouting hole 111 into the expanded borehole; if the piston 131 reaches the lowest stroke, the feed valve 1312 is opened to replenish material. During the grouting process, the lifting mechanism 2 continues to rise to complete the overall cement slurry pouring of the target drilling section.

[0023] The technical effect of the above technical solution is as follows: the soil around the borehole is squeezed by the expansion airbag 121 in the extrusion expansion assembly 12, thereby expanding the borehole diameter. The larger aperture provides space for pouring more cement slurry, which increases the thickness of the final water-proof cement ring, can more effectively block the flow of groundwater in the upper and lower layers, and significantly improve the water-proof effect; the expansion airbag 121 pre-expands the borehole, compacts the loose soil on the inner wall of the borehole and expands the aperture, forming a regular and flat borehole wall interface, so that the subsequently injected cement slurry fits tightly with the borehole wall, eliminating the bonding gap caused by the roughness of the borehole wall in the traditional method. In addition, the piston 131 and the extrusion drive 132 in the extrusion assembly 13 cooperate with the grouting assembly 14, and the extrusion drive 132 drives the piston 131 to descend, forcing the cement slurry in the grouting tube 11 out of the grouting hole 111. This method can increase the pressure of the sprayed cement slurry, so that the cement slurry can be more fully filled into the expanded borehole space, and reduce the occurrence of hollowing in the injected cement slurry. Denser cement slurry filling can effectively improve the reliability of sealing and further ensure the sealing effect of the waterproof layer.

[0024] In one embodiment, see Figure 1-Figure 3, the lifting mechanism 2 includes a plurality of casings 21 and a static probe 22 that are detachably connected end to end. The grouting barrel 11 is installed at the lower end of the lowest casing 21. The static probe 22 is connected to the casing 21 assembly and is used to drive the casing 21 assembly to rise and fall. In this embodiment, the casing 21 assembly composed of a plurality of casings 21 that are detachably connected end to end can be flexibly spliced according to the drilling depth requirements. When waterproof layers of different depths need to be sealed, the grouting barrel 11 can be accurately adjusted to the specified depth by increasing or decreasing the number of casings 21 to meet the actual needs of various engineering sites.

[0025] In one embodiment, see Figure 1-Figure 3 , two adjacent sleeves 21 are threadedly connected.

[0026] In one embodiment, see Figures 1-4 The outer wall of the grouting tube 11 is formed with a mounting groove, and the expansion airbag 121 is located in the mounting groove. In this embodiment, the mounting groove provides an adaptive installation space for the expansion airbag 121, which can provide it with a certain degree of protection. During the process of inserting the grouting tube 11 into the borehole and moving within the borehole, the groove can reduce direct friction and collision with the inner wall of the borehole on the airbag, reducing the risk of damage to the airbag.

[0027] In one embodiment, see Figures 1-4 A fixed block 112 is fixed in the grouting barrel 11, and a guide hole 1121, a first through hole 1122 and a second through hole 1123 are provided on the fixed block 112; the gas injection assembly 122 includes a gas injection pipe 1221 and a gas injection pump 1222, one end of the gas injection pipe 1221 is connected to the gas injection port of the expansion airbag 121, and the other end is detachably connected to the gas injection pump 1222 after passing through the first through hole 1122. During assembly, after one end of the gas injection pipe 1221 is connected to the gas injection port of the expansion airbag 121, the other end is not connected to the gas injection pump 1222 first, but passes through each sleeve 21 in turn. When each new sleeve 21 is connected, the gas injection pipe 1221 is inserted into the sleeve 21 in advance, and then the sleeves 21 are connected. After all the sleeves 21 are connected, the other end of the gas injection pipe 1221 is connected to the outlet of the gas injection pump 1222. This installation method combines the installation of the gas injection tube 1221 with the connection process of the casing 21. The gas injection tube 1221 is pre-inserted when connecting each casing 21, avoiding the complex operation of inserting individual pipes after all casings 21 are connected. This greatly simplifies the installation process, reduces operational inconveniences caused by problems such as limited space and difficulty in inserting pipes, and improves the efficiency of equipment assembly.

[0028] In one embodiment, see Figures 1-4The extrusion drive member 132 includes an extrusion drive electric rod, the fixed end of which is fixed in the grouting cylinder 11, and the output end of which passes through the guide hole 1121 and is fixedly connected to the piston 131. The extrusion drive electric rod is connected to the ground power supply equipment via a wire, so that it can be powered by the power supply. The wire is pre-inserted into each sleeve 21 to facilitate installation.

[0029] In one embodiment, see Figures 1-4 The casing grouting method water-blocking layer plugging device also includes a control component, which is in communication with the extrusion drive electric rod and the lifting mechanism 2, and is used to obtain the extension rate of the output shaft of the extrusion drive electric rod, and control the rising speed of the lifting mechanism 2 according to the extension rate of the output shaft of the extrusion drive electric rod. By obtaining the extension rate of the output shaft of the extrusion drive electric rod, the control component can understand in real time the speed at which the cement slurry is squeezed out of the grouting hole 111. Based on this, the control component adjusts the rising speed of the lifting mechanism 2 accordingly so that the grouting speed matches the rising speed of the grouting barrel 11. For example, when the extrusion drive electric rod quickly pushes out the piston 131 and the cement slurry is squeezed out at a faster speed, the control component accelerates the rising speed of the lifting mechanism 2 to ensure that the amount of cement slurry injected at different heights per unit time is relatively uniform, thereby improving the uniformity of the thickness of the cement ring finally formed. This is crucial to ensuring the sealing effect of the water-blocking layer. A cement ring with uniform thickness can more effectively block the flow of groundwater and reduce the risk of leakage caused by insufficient local thickness.

[0030] In one embodiment, see Figures 1-4 The grouting assembly 14 includes a grouting pipe 141, a grouting pump 142 and a slurry tank 143. One end of the grouting pipe 141 is connected to the feed port 1311, and the other end is detachably connected to the outlet of the grouting pump 142 after passing through the second through hole 1123. The inlet of the grouting pump 142 is connected to the slurry tank 143. During assembly, after one end of the grouting pipe 141 is connected to the feed port 1311, the other end is not connected to the grouting pump 142 first, but passes through each sleeve 21 in turn. When each new sleeve 21 is connected, the grouting pipe 141 is inserted into the sleeve 21 in advance, and then the sleeve 21 is connected. After all the sleeves 21 are connected, the other end of the grouting pipe 141 is connected to the outlet of the grouting pump 142. The method of synchronously inserting the grouting pipe 141 during the connection process of the sleeve 21 greatly simplifies the installation process of the grouting assembly 14. Compared to inserting the pipe after all the sleeves 21 are connected, this method avoids the difficulty of inserting the pipe due to the small internal space and long length of the sleeve 21, making the installation operation smoother and more efficient. The grouting pipe 141 is pre-inserted when each sleeve 21 is connected, which reduces the obstacles and complexity of the installation process, saves installation time, and improves overall construction efficiency.

[0031] In one embodiment, see Figures 1-4 The casing grouting waterproof layer sealing device also includes a drill bit 3, which is detachably fixed to the lower end of the grouting cylinder 11. The tip of the drill bit 3 can clear the borehole to prevent the grouting pipe 141 from being blocked in the borehole.

[0032] The present invention also provides a casing grouting method for sealing a water barrier layer, which is applicable to the casing grouting method for sealing a water barrier layer, and comprises the following steps: S1, assembling the device, lowering the grouting cylinder 11 into the drill hole through the lifting mechanism 2; S2, when the grouting hole 111 of the grouting cylinder 11 reaches the lowermost end of the drilling section that needs grouting and plugging, it stops descending; S3, injecting air into the expansion airbag 121 through the air injection assembly 122 to expand it and squeeze the surrounding soil to enlarge the borehole diameter. After squeezing, the expansion airbag 121 is deflated, and the lifting mechanism 2 drives the grouting barrel 11 to rise to the height of the expansion airbag 121. The cycle of air injection-squeezing-deflation-raising is repeated to perform overall squeezing and expanding of the target borehole section. S4. The lifting mechanism 2 drives the grouting barrel 11 to descend to the lowest end of the target drilling section, opens the feed valve 1312, and injects cement slurry into the grouting barrel 11 through the grouting assembly 14. After closing the feed valve 1312, the extrusion drive 132 drives the piston 131 to descend, and presses the cement slurry from the grouting hole 111 into the expanded borehole; if the piston 131 reaches the lowest stroke, open the feed valve 1312 to add material. During the grouting process, the lifting mechanism 2 continues to rise to complete the overall cement slurry pouring of the target drilling section.

[0033] Please refer to Figure 4 The waterproofing principle of the present application is as follows: the upper aquifer 100 and the lower aquifer 200 are isolated by the waterproofing layer 300. Through this device, a waterproof cement ring 400 can be formed in the entire section of the upper aquifer 100 and the upper section of the waterproofing layer in the borehole. The waterproof cement ring 400 is in close contact with the soil on the inner wall of the borehole, which can prevent the upper aquifer 100 and the lower aquifer 200 from being connected through the borehole.

[0034] The technical effects of the technical solution provided by this application include: (1) The expansion airbag 121 in the extrusion expansion assembly 12 is used to squeeze the soil around the borehole and expand the borehole diameter. A larger borehole diameter provides space for injecting more cement slurry, which increases the thickness of the final water-proof cement ring and can more effectively block the flow of groundwater in the upper and lower layers, significantly improving the water-proof effect; the expansion airbag 121 is used to pre-extrude the borehole, compacting the loose soil on the inner wall of the borehole and expanding the borehole diameter to form a regular and flat borehole wall interface, so that the subsequently injected cement slurry fits tightly with the borehole wall, eliminating the bonding gap caused by the roughness of the borehole wall in the traditional method. In addition, the piston 131 and the extrusion drive 132 in the extrusion assembly 13 cooperate with the grouting assembly 14, and the extrusion drive 132 drives the piston 131 to descend, squeezing the cement slurry in the grouting tube 11 out of the grouting hole 111. This method can increase the pressure of the ejected cement slurry, so that the cement slurry can be more fully filled into the expanded borehole space, and reduce the occurrence of hollowing in the injected cement slurry. Denser cement slurry filling can effectively improve the reliability of sealing and further ensure the sealing effect of the waterproof layer.

[0035] (2) The control unit can obtain the extension rate of the output shaft of the extrusion drive electric rod and understand in real time the speed at which the cement slurry is squeezed out of the grouting hole 111. Based on this, the control unit adjusts the rising speed of the lifting mechanism 2 accordingly to match the grouting speed with the rising speed of the grouting tube 11. For example, when the extrusion drive electric rod quickly pushes out the piston 131 and the cement slurry is squeezed out at a faster speed, the control unit accelerates the rising speed of the lifting mechanism 2 to ensure that the amount of cement slurry injected at different heights per unit time is relatively uniform, thereby improving the uniformity of the thickness of the cement ring finally formed.

[0036] The specific implementation methods of the present application described above do not constitute a limitation on the scope of protection of the present application. Any other corresponding changes and modifications made based on the technical concept of the present application should be included in the scope of protection of the present application.

Claims

1. A casing grouting method water-insulating layer plugging device, characterized in that: It comprises a blocking mechanism (1) and a lifting mechanism (2); The blocking mechanism (1) comprises a grouting cylinder (11), an extrusion hole expansion assembly (12), an extrusion assembly (13) and a grouting assembly (14); the grouting cylinder (11) is used to be inserted into a drill hole, its lower end is closed, and a plurality of grouting holes (111) are opened on the outer side wall of the lower end; the extrusion hole expansion assembly (12) comprises an expansion airbag (121) and an air injection assembly (122); the expansion airbag (121) is sleeved on the outer side wall of the grouting cylinder (11), and the air injection assembly (122) is connected to the air injection port of the expansion airbag (121) to allow the expansion airbag (121) to be expanded. The sac (121) expands or contracts; the extrusion assembly (13) includes a piston (131) and an extrusion drive member (132); the piston (131) is sealingly and slidably arranged in the grouting cylinder (11); a feed port (1311) is provided on the piston (1311); a feed valve (1312) is provided on the feed port (1311); an output end of the extrusion drive member (132) is connected to the piston (131) for driving the piston (131) to move up and down; the grouting assembly (14) is communicated with the feed port (1311); The lifting mechanism (2) is connected to the grouting cylinder (11) and is used to enable the grouting cylinder (11) to be lifted and lowered in the drill hole.

2. The waterproof layer plugging device using casing grouting method according to claim 1, characterized in that: The lifting mechanism (2) comprises a plurality of sleeves (21) and a static penetration machine (22) which are detachably connected end to end. The grouting cylinder (11) is installed at the lower end of the lowermost sleeve (21). The static penetration machine (22) is connected to the sleeve (21) assembly and is used to drive the sleeve (21) assembly to rise and fall.

3. The waterproof layer plugging device using casing grouting method according to claim 2, characterized in that: The two adjacent sleeves (21) are threadedly connected.

4. The waterproof layer plugging device using casing grouting method according to claim 1, characterized in that: An installation groove is formed on the outer side wall of the grouting cylinder (11), and the expansion airbag (121) is located in the installation groove.

5. The waterproof layer plugging device using casing grouting method according to claim 1, characterized in that: A fixed block (112) is fixed in the grouting cylinder (11), and a guide hole (1121), a first through hole (1122), and a second through hole (1123) are provided on the fixed block (112); the gas injection assembly (122) comprises a gas injection pipe (1221) and a gas injection pump (1222); one end of the gas injection pipe (1221) is connected to the gas injection port of the expansion airbag (121), and the other end passes through the first through hole (1122) and is detachably connected to the gas injection pump (1222).

6. The waterproof layer plugging device using casing grouting method according to claim 5, characterized in that: The extrusion drive member (132) comprises an extrusion drive electric rod, the fixed end of the extrusion drive electric rod is fixed in the grouting cylinder (11), and the output end passes through the guide hole (1121) and is fixedly connected to the piston (131).

7. The waterproof layer plugging device using casing grouting method according to claim 6, characterized in that: The device further comprises a control member, which is in communication with the extrusion drive electric rod and the lifting mechanism (2) and is used to obtain the extension rate of the output shaft of the extrusion drive electric rod and control the rising speed of the lifting mechanism (2) according to the extension rate of the output shaft of the extrusion drive electric rod.

8. The waterproof layer plugging device using casing grouting method according to claim 5, characterized in that: The grouting assembly (14) comprises a grouting pipe (141), a grouting pump (142) and a slurry tank (143); one end of the grouting pipe (141) is connected to the feed port (1311); the other end passes through the second through hole (1123) and is detachably connected to the outlet of the grouting pump (142); the inlet of the grouting pump (142) is connected to the slurry tank (143).

9. The waterproof layer plugging device using casing grouting method according to claim 1, characterized in that: It also includes a drill bit (3), which is detachably fixed to the lower end of the grouting cylinder (11).

10. A method for sealing a water-insulating layer by casing grouting, characterized in that: The device is applicable to the waterproof layer plugging device using the casing grouting method as claimed in any one of claims 1 to 9, and comprises the following steps: S1, assembling the device, lowering the grouting cylinder (11) into the drill hole through the lifting mechanism (2); S2, when the grouting hole (111) of the grouting cylinder (11) reaches the lowermost end of the drilling section that needs grouting and plugging, the grouting cylinder (11) stops descending; S3, injecting air into the expansion airbag (121) through the air injection assembly (122), causing it to expand and squeeze the surrounding soil to enlarge the borehole diameter; after squeezing, the expansion airbag (121) is deflated, and the lifting mechanism (2) drives the grouting cylinder (11) to rise to the height of the expansion airbag (121); repeating the cycle of air injection-squeezing-deflation-rising, and performing overall squeezing and expanding on the target borehole section; S4, the lifting mechanism (2) drives the grouting barrel (11) to descend to the lowest end of the target drilling section, opens the feed valve (1312), and injects cement slurry into the grouting barrel (11) through the grouting assembly (14). After closing the feed valve (1312), the extrusion drive member (132) drives the piston (131) to descend, and squeezes the cement slurry out of the grouting hole (111) into the expanded borehole; if the piston (131) reaches the lowest stroke, the feed valve (1312) is opened to add material. During the grouting process, the lifting mechanism (2) continues to rise, and the overall cement slurry grouting of the target drilling section is completed.

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