A method for grouting the bottom of an underwater prefabricated component

Abstract

This invention belongs to the field of underwater renovation and expansion construction of buildings or structures, and specifically relates to a method for bottom grouting of underwater precast components. The technical problem this invention aims to solve is that existing grouting methods cannot meet the design requirements of the grouting structural layer. This invention discloses a method for bottom grouting of underwater precast components, including a grouting process. During controlled-pressure grouting, drainage and air release are achieved through a grouting pipe connected to the grouting cavity and a connecting pipe independent of the grouting pipe but connected to the grouting cavity. The grouting pressure is controlled during controlled-pressure grouting to maintain the sealing effect of the bottom sealant of the precast component and to ensure that the grout completely fills the grouting cavity. The technical effect achieved by this invention is that it ensures that the grout does not overflow due to excessive grouting pressure, while also solving the problem of the grout not completely filling the grouting cavity, ultimately meeting the design requirements of the grouting structural layer.

Description

Technical Field

[0001] This invention belongs to the field of underwater renovation and expansion construction of buildings or structures, and in particular relates to a method for bottom grouting of underwater prefabricated components. Background Technology

[0002] To eliminate the Karman vortex street phenomenon, during construction, new flow guiding structures combining triangles, trapezoids, and ellipses will be built upstream and downstream of the existing piers, columns, guide walls, and other structures.

[0003] Chinese invention patent application No. 202210411917.5, published on August 16, 2022, discloses an underwater prefabricated precast guide pier, including a first precast slab, a sealing part arranged in a closed ring on the bottom slab of the first precast slab, and a grouting part arranged on the bottom slab of the first precast slab. The sealing part is used to connect with the bottom slab of the original building to form a filling cavity. The grouting part has a first state that connects the filling cavity and the upper space of the bottom slab of the first precast slab, and a second state that blocks the filling cavity and the upper space of the bottom slab of the first precast slab. The sealing part includes a water-stop embedded part and a rubber water-stop strip, and the grouting part is a grouting pipe.

[0004] Chinese invention patent application No. 202210411918.X, published on August 16, 2022, discloses a sunken mounting base and installation method for modifying and expanding hydraulic structures. The base includes a connecting part of an operating cavity with an upper opening structure, a sealing part arranged in a closed ring on the bottom plate of the operating cavity, and a grouting part arranged on the bottom plate of the operating cavity. The sealing part is used to connect with the bottom plate of the original structure to form a filling cavity (i.e., a grouting cavity). The grouting part has a first state that connects the filling cavity and the operating cavity, and a second state that blocks the filling cavity and the operating cavity. The sealing part includes a water-stop embedded part and a rubber water-stop strip, and the grouting part is a grouting pipe.

[0005] When grouting the filling cavities in the aforementioned existing technologies, common grouting methods include the self-weight method, the high-level funnel method, and the pressure grouting method. However, due to structural limitations, regardless of the grouting method, it is difficult to expel the air and water from the grouting cavity, which cannot meet the design requirements of the grouting structural layer. Furthermore, although the pressure grouting method can stabilize the grouting pressure, when the pressure is too high, the resulting vertical load approaches the self-weight of the underwater precast component (guide pier), reducing the compression of the sealing part. The grout will overflow from areas with significant unevenness (i.e., unevenness) in the original building's foundation slab, failing to meet the design requirements of the grouting structural layer. Conversely, when the grout pressure is too low, the grout cannot completely fill the filling cavity, also failing to meet the design requirements of the grouting structural layer. Summary of the Invention

[0006] The purpose of this invention is to provide a bottom grouting method for underwater precast components, so as to solve the technical problem that the existing grouting methods cannot meet the design requirements of the grouting structure layer.

[0007] To achieve the above objectives, the technical solution of the underwater precast component bottom grouting method provided by the present invention is as follows:

[0008] A method for bottom grouting of underwater precast components includes a grouting process. During the controlled pressure grouting process, drainage and air are vented through a grouting pipe connected to the grouting cavity and a connecting pipe that is separate from the grouting pipe but connected to the grouting cavity. The grouting pressure is controlled during the controlled pressure grouting process to maintain the sealing effect of the bottom sealant of the precast component and to ensure that the grout can fill the grouting cavity.

[0009] The beneficial effects are as follows: This invention is an improved invention. During the controlled-pressure grouting process, by setting up connecting pipes and grouting pipes, water and air in the grouting cavity can be discharged from the pipes. By controlling the grouting pressure at the grouting pipe, it is possible to ensure that the grout does not overflow due to excessive grouting pressure, while also solving the problem of the grout not completely filling the grouting cavity, ultimately meeting the design requirements of the grouting structural layer.

[0010] Furthermore, during the controlled pressure grouting process, the grouting pressure is 0.5-0.7 times the weight of the precast component.

[0011] The beneficial effects are as follows: by controlling the grouting pressure to be 0.5-0.7 times the weight of the precast component, it is possible to ensure that the grout fills the grouting cavity while avoiding the grout lifting the precast component upward (that is, under the condition of ignoring the elasticity of the sealing part, the upward force of the grout on the precast component plus the buoyancy of the precast component should be less than the weight of the precast component), thus solving the problem that the grout cannot completely fill the grouting cavity and meeting the design requirements of the grouting structure layer.

[0012] Furthermore, during the drainage and venting process through the connecting pipe and grouting pipe, it is ensured that the lower ends of the connecting pipe and grouting pipe are flush with the lower surface of the precast component base plate.

[0013] The beneficial effects are: during the grouting process, by making the lower ends of the connecting pipe and the grouting pipe flush with the lower surface of the precast component base plate, the vertical space for grouting can be reserved as much as possible, and water and air can be discharged as much as possible.

[0014] Furthermore, before the pressure-controlled grouting process, an air venting pipe for venting air and water from the grouting cavity is installed inside the sealing part. One end of the air venting pipe is located inside the connecting pipe, and the other end is located in the grouting cavity on the side farther from the connecting pipe.

[0015] The beneficial effects are as follows: During the grouting process, by setting up an air vent pipe, water and air on the side farther away from the grouting pipe and connecting pipe can be discharged from the grouting cavity through the air vent pipe, which is conducive to the complete discharge of water and air in the grouting cavity, so that the grouting structure layer meets the design requirements.

[0016] Furthermore, the air intake pipe is fixed to the lower surface of the precast component base plate.

[0017] The beneficial effects are: by fixing the air intake pipe to the lower surface of the precast component, the air intake pipe is prevented from being blocked by the grout at the beginning of grouting, and the air intake pipe is located above the grouting cavity, so as to discharge as much water and air as possible from the grouting cavity.

[0018] Furthermore, during the pressure-controlled grouting process, the grouting pressure is controlled by a pressure-controlled grouting pipe and an overflow pipe located on the side of the pressure-controlled grouting pipe and connected to it. The height of the connection between the overflow pipe and the pressure-controlled grouting pipe from the bottom of the precast component is [missing information]. Where 0.5≤n≤0.7, m 预制构件 For the quality of precast components, S 预制构件 ρ is the base area of ​​the precast component. 浆液 This represents the density of the slurry.

[0019] The beneficial effects are as follows: During the grouting process, by setting up a pressure-controlled grouting pipe and an overflow pipe, the grouting pressure can be controlled more conveniently. Simultaneously, placing the overflow pipe on the side of the pressure-controlled grouting pipe allows for the placement of a water tank to hold the grout below the overflow port, preventing grout overflow and contamination of the precast components. Furthermore, pressure control via the pressure-controlled grouting pipe and overflow port is more convenient and cost-effective compared to other pressure control methods.

[0020] Furthermore, the grout is made by mixing 32.5R early-type silicate cement with water, and the water-cement ratio is 0.5:1.

[0021] The beneficial effects are as follows: According to the results of multiple slurry preparation tests, slump tests and fluidity tests, after comprehensively comparing factors such as fluidity, cementing performance, stone strength, construction convenience and economy, the slurry made by mixing 32.5R early type silicate cement with water and the water-cement ratio of 0.5:1 has the best effect.

[0022] Furthermore, the following steps are used for step-by-step grouting during the pressure-controlled grouting process:

[0023] The first step is to open any one of the gate valves of the grouting pipe and the gate valve of the connecting pipe closest to that grouting pipe;

[0024] The second step is to set the pressure-controlled grouting pipe on the open grouting pipe and perform grouting. After the grout of the same concentration as the grouting slurry overflows from the connecting pipe closest to the grouting pipe, close the gate valve of the connecting pipe to complete the grouting construction of the grouting pipe.

[0025] The third step is to open the gate valve of another grouting pipe and the gate valve of the connecting pipe closest to the grouting pipe, and repeat the operations of the first and second steps until all grouting pipes have completed the grouting construction.

[0026] The beneficial effects are: by grouting in stages, the grout can be filled to the maximum extent possible, and the air and water in the grouting cavity can be discharged as much as possible, thus meeting the design requirements of the grouting structure layer.

[0027] Furthermore, after the pressure-controlled grouting process is completed, a vibration venting process is also included: after sinking a vibrator into any grouting pipe and vibrating it for 5-10 minutes, a small amount of grout is added from other grouting pipes for supplementary grouting. After water overflows from the pressure-controlled overflow hole of the grouting part that was submerged in the vibrator, the vibration is stopped. Then, the above operation is repeated with other grouting pipes until the above operation is completed at all grouting parts.

[0028] The beneficial effects are: after the pressure-controlled grouting process, the small amount of residual gas can be drawn out and discharged from the grouting cavity by vibration venting and replenishment, and the grout can ensure that the cavity at the bottom of the precast component is filled more densely, thus meeting the design requirements of the grouting structure layer.

[0029] Furthermore, the pressure-controlled grouting pipe is detachably connected to the grouting pipe.

[0030] The beneficial effect is that by detachably connecting the pressure-controlled grouting pipe to the grouting part, the pressure-controlled grouting pipe can be reused, reducing costs. Attached Figure Description

[0031] Figure 1 This is a block diagram of the precast component used in a specific embodiment 1 of the underwater precast component bottom grouting method of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the precast component used in a specific embodiment 1 of the underwater precast component bottom grouting method of the present invention;

[0033] Figure 3 This is a schematic diagram of the bottom structure of the precast component used in a specific embodiment 1 of the underwater precast component bottom grouting method of the present invention;

[0034] Figure 4 This is a schematic diagram of the air intake pipe installation plan of the prefabricated component used in a specific embodiment 1 of the underwater prefabricated component bottom grouting method of the present invention;

[0035] Figure 5 This is a cross-sectional view of the air intake pipe installation of the prefabricated component used in a specific embodiment 1 of the underwater prefabricated component bottom grouting method of the present invention;

[0036] Figure 6 This is a schematic diagram of the sinking and positioning of the precast component to the original building base slab in a specific embodiment 1 of the underwater precast component bottom grouting method of the present invention;

[0037] Figure 7 This is a schematic diagram of the installation of the pressure-controlled grouting pipe in a specific embodiment 1 of the underwater prefabricated component bottom grouting method of the present invention;

[0038] Figure 8 This is a schematic diagram of the grout flow in the grouting cavity in a specific embodiment 1 of the underwater precast component bottom grouting method of the present invention;

[0039] Figure 9 This is a schematic diagram of the grouting cavity filled with grout in a specific embodiment 1 of the underwater prefabricated component bottom grouting method of the present invention.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. First section of precast component; 2. Second section of precast component; 3. Third section of precast component; 4. Fourth section of precast component; 5. Water-stop rubber steel embedded part; 6. Hollow water-stop rubber; 7. Grouting pipe; 7a. First grouting pipe; 7b. Second grouting pipe; 7c. Third grouting pipe; 7d. Fourth grouting pipe; 8. Connecting pipe; 8a. First connecting pipe; 8b. Second connecting pipe; 8c. Third connecting pipe; 8d. Fourth connecting pipe; 9. U-shaped buckle; 10. Expansion bolt; 11. Air vent pipe; 12. Grouting pipe gate valve; 13. Connecting pipe gate valve; 14. Pressure-controlled grouting pipe; 15. Overflow pipe. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the embodiments.

[0043] Specific embodiment 1 of the underwater precast component bottom grouting method provided by the present invention:

[0044] like Figure 1-9 As shown, the underwater prefabricated component bottom grouting method provided by the present invention is implemented according to the following steps:

[0045] S1. Prefabricated components are manufactured in the factory.

[0046] like Figure 1-2As shown, the prefabricated components used in this invention are divided into prefabricated component segment 1, prefabricated component segment 2, prefabricated component segment 3, and prefabricated component segment 4. When manufacturing the prefabricated components, the working conditions during installation must be fully considered. For example, the original gate chamber pier width is 5m, the elevation of the pier bottom plate is 128.0m (i.e., the original building bottom plate is located at a height of 128.0m), the design water level is 134.6m, the design water level is 135.3m, and the original pier top elevation is 136.155m. The newly constructed prefabricated component is 10m long and 8.155m high. The precast components are divided into four sections along the length direction, with effective lengths of 0.95m, 2.5m, 2.5m and 4.05m respectively; and into ten layers along the height direction. The bottom layer with a base plate has a height of 0.8m, the second to ninth layers are standard layers with a height of 0.8m, and the top tenth layer is a cast-in-place layer with a height of 0.955m.

[0047] Of course, in other embodiments, the precast components need not be divided into four sections, nor into ten layers, nor 10m long and 8.155m high. Only the following two points need to be guaranteed: First, the curvature and width of the first precast component need to be able to be combined with the original building gate pier; Second, the cumulative height of the precast layer needs to be higher than the water surface to ensure that the cast-in-place layer is constructed on the water.

[0048] like Figure 3 As shown, the bottom precast block of each precast component is a thin-walled hollow structure with a base plate. The lower part of the base plate is equipped with a sealing part, a grouting pipe 7, and a connecting pipe 8. The sealing part is a hollow water-stop rubber 6 that is compressed and installed on a water-stop rubber steel embedded part 5 after the precast block base plate contacts the original building base plate. The sealing part and the original building base plate form a grouting cavity, and the water-stop rubber steel embedded part 5 is embedded in the precast component. In this embodiment, the grouting pipe 7 and the connecting pipe 8 are both steel pipes installed on and penetrating the base plate. However, in other embodiments, the grouting pipe 7 and the connecting pipe 8 can also be through holes installed on the base plate and penetrating the base plate. As long as the through hole has length, it can be considered a pipe. The thin-walled hollow concrete precast component can be precast in a factory. During precasting, it is fixed with an inner mold and then tied with steel knots. Subsequently, the water-stop rubber steel embedded part 5, the grouting pipe 7, and the connecting pipe 8 are embedded. After all embedded parts are installed, the outer mold is installed, and concrete is poured.

[0049] S2. Install the ventilator tube.

[0050] like Figure 4-5As shown, the air venting pipe 11, used to drain air and water from the grouting cavity, is fixed to the lower surface of the precast component base plate using U-shaped clips 9 and expansion bolts 10. In this embodiment, the air venting pipe 11 is a steel pipe with a diameter of 10-20 mm, but in other embodiments, the air venting pipe 11 can also be a PVC pipe of other diameters, etc. One end of the air venting pipe 11 is located inside the connecting pipe 8, and the other end is located on the side of the grouting cavity farther from the grouting pipe 7 and the connecting pipe 8.

[0051] S3. Lower the precast components into place.

[0052] like Figure 6 As shown, a water-stop rubber, a grouting pipe gate valve 12, and a connecting pipe gate valve 13 are installed on the precast components. After installation, the gate valves are closed. Specialized equipment is used to complete the installation of the precast components on the water surface, and the precast components are then sunk and positioned onto the bottom slab of the original underwater structure according to design requirements.

[0053] S4. Drain the water from the grouting cavity.

[0054] After the precast component is lowered into place, open either the connecting pipe gate valve 13 or the grouting pipe gate valve 12 to allow the high-pressure water in the grouting cavity to spray out. Then, use a water pump to empty the water in the grouting cavity.

[0055] S5. Install pressure-controlled grouting pipe

[0056] like Figure 7 As shown, the gate valve 12 of the grouting pipe is removed. A pressure-controlled grouting pipe 14 for controlling the grouting pressure and an overflow pipe 15 located on the side of the pressure-controlled grouting pipe 14 and connected to it are installed on the top of the grouting pipe 7. The main function of the overflow pipe 15 is to overflow, so the overflow pipe 15 should not be too long and should not accumulate a large amount of grout. The grouting pipe 7 and the pressure-controlled grouting pipe 14 are connected. In this embodiment, the pressure-controlled grouting pipe 14 is inserted into the grouting pipe 7, but in other embodiments, the pressure-controlled grouting pipe 14 can be integrally formed with the grouting pipe 7, or it can be connected to the grouting pipe 7 by bolts. By making the pressure-controlled grouting pipe 14 detachable, it can be removed and cleaned 1-2 hours before the grout reaches its initial setting after the grouting construction is completed, for future use. Before the grout initially sets, there is no change in live load on the top of the precast component, thereby ensuring that the grouting structure layer at the bottom of the precast component solidifies under uniform stress.

[0057] In calculating the grouting pressure, the grout in the overflow pipe 15, atmospheric pressure, liquid in the connecting pipe, and residual water in the grouting cavity can be ignored. When injecting grout into the pressure-controlled grouting pipe 14, the grout level will overflow from the overflow port of the overflow pipe 15 after reaching the preset upper limit, thus ensuring that the grouting pressure does not change. The reference value for the height of the connection between the overflow pipe and the pressure-controlled grouting pipe from the bottom of the precast component is... Where 0.5≤n≤0.7, m 预制构件 For the quality of precast components, S 预制构件 ρ is the base area of ​​the precast component. 浆液 This refers to the density of the grout. For example, a precast component has a self-weight of 48t and a base area of ​​8m². 2 The density of water is 1 t / m³ 3 The density of silicate cement is approximately 3.1 t / m³. 3 The water-cement ratio is 1:0.5, the cement usage is 1 / 0.5 = 2t, and the volume of 2t cement is 2 / 3.1 = 0.645m³. 3 Therefore, the density of the cement grout is (1+2) / (1+0.645)=1.8t / m³ 3 The grouting pressure is taken as 0.5-0.7 times the self-weight of the precast component. In this example, 0.6 times is taken, so the grouting pressure is 28.8t. The controlled pressure of the grout during grouting is 28.8 / 8 = 3.6t / m. 2 The overflow outlet height is 3.6 / 1.8 = 2m. Therefore, the pressure-controlled grouting pipe 14 opens approximately 2m from the bottom of the precast component, and an inclined overflow pipe 15 is welded in, making the distance between the overflow outlet and the bottom of the precast component approximately 2m. Alternatively, in other embodiments, the pressure-controlled grouting pipe 14 can open approximately 1m from the bottom of the precast component, making the distance between the overflow outlet and the bottom of the precast component approximately 2m.

[0058] In this embodiment, the reason why the grouting pressure is 0.5-0.7 times the self-weight of the precast component (0.5≤n≤0.7) is as follows:

[0059] When the grout pressure is too high, the resulting vertical load approaches the weight of the underwater precast component (guide pier) (i.e., when n approaches 1). The compression of the sealing part decreases, and the grout overflows from areas with significant unevenness in the original building's base slab, failing to meet the design requirements of the grouting structural layer. Conversely, when the grout pressure is too low (i.e., when n approaches 0), the grout cannot completely fill the grouting cavity, also failing to meet the design requirements of the grouting structural layer. Therefore, a grouting pressure between 0 and 1 times the weight of the precast component is optimal. After multiple tests, it was found that when the precast component includes the connecting pipe 8, a grouting pressure of 0.5-0.7 times the weight of the precast component ensures complete filling of the grouting cavity while preventing the grout from lifting the precast component upwards (i.e., ignoring the elasticity of the sealing part, the upward force exerted by the grout on the precast component plus the buoyancy force on the precast component should be less than the weight of the precast component), thus better meeting the design requirements of the grouting structural layer. When the flatness of the original building channel bottom plate is poor, a smaller value is used; when the flatness of the original building channel bottom plate is good, a larger value is used. In this way, sufficient pressure can be ensured during grouting, but excessive pressure will not cause the precast components to be lifted up and the rubber waterstop to fail, and the grout will overflow from the gap between the rubber and the original building channel bottom plate into the water conveyance channel and pollute the water body.

[0060] In this embodiment, the grouting pressure is controlled by installing a pressure-controlled grouting pipe. However, in other embodiments, the grouting pressure can also be controlled in other ways, such as placing a funnel at the upper opening of the grouting pipe and ensuring that the distance between the upper opening of the grouting pipe and the bottom of the precast component is [missing information]. The grouting pressure can be stabilized by controlling the rate at which grout is delivered into the funnel, or by using a pressure-stabilizing grouting machine. However, compared to other embodiments, this embodiment makes pressure control more convenient at a lower cost.

[0061] S6. Prepare slurry

[0062] To avoid water pollution and considering functional requirements, this embodiment uses solid grouting materials. Commonly used solid grouting materials include clay grout, cement grout, cement-fly ash grout, and high-strength grout. Through grouting tests, slump tests, and fluidity tests, and considering factors such as fluidity, bonding performance, aggregate strength, ease of construction, and economy, cement grout is used for the bottom grouting of precast components in this embodiment. The grout is prepared by mixing 32.5R early-type silicate cement with water at a water-cement ratio of 0.5:1. 200 kg of cement is mixed with 100 kg of water, and 1 t of water can produce 1.645 m³ of grout. 3Cement grout was prepared according to the water-cement ratio to meet the construction schedule and dosage. Of course, other grouts can be used in other embodiments, but according to the results of multiple grouting tests, slump tests and fluidity tests, when considering factors such as fluidity, bonding performance, aggregate strength, ease of construction and economy, the grout prepared by mixing 32.5R early-type silicate cement with water and a water-cement ratio of 0.5:1 has the best effect.

[0063] S7, Grouting

[0064] like Figure 7 As shown, a funnel is placed at the top of the pressure-controlled grouting pipe 14, and grout is injected from the top of the pipe 14 while the gate valve at the top of the connecting pipe 8 is opened. The grout flows into the grouting cavity under gravity. As the grout continues to be injected, it accumulates to a certain height and gradually fills the circumference of the grouting pipe 7, spreading outwards from the grouting pipe 7 as the center line. Because the density of the grout is greater than that of water, any remaining water and air in the grouting cavity will overflow from the connecting pipe 8 under the force of the grout. Simultaneously, containers such as buckets can be used to collect the accumulated water and overflowing grout.

[0065] like Figure 7-9 As shown, the precast component of the present invention has at least two grouting pipes 7 and matching connecting pipes 8. In this embodiment, there are four grouting pipes 7, namely a first grouting pipe 7a, a second grouting pipe 7b, a third grouting pipe 7c, and a fourth grouting pipe 7d; there are four connecting pipes 8, namely a first connecting pipe 8a, a second connecting pipe 8b, a third connecting pipe 8c, and a fourth connecting pipe 8d. The following steps are used for pressure-controlled grouting:

[0066] The first step is to open any grouting section and the connecting pipe 8 closest to that grouting section. In this embodiment, the gate valves of the first grouting pipe 7a and the first connecting pipe 8a are opened.

[0067] The second step is to set the pressure-controlled grouting pipe 14 on the open grouting pipe for grouting. After the grout of the same concentration as the grouting slurry overflows from the connecting pipe 8 closest to the grouting pipe, the connecting pipe 8 closest to it is closed. In this embodiment, the pressure-controlled grouting pipe 14 is set on the first grouting pipe 7a for grouting. Since the first connecting pipe 8a is closest to the first grouting pipe 7a, there will be water and slurry overflowing from the first connecting pipe 8a. After the water overflowing from the first connecting pipe 8a becomes slurry of the same concentration as the slurry in the first grouting pipe 7a, the gate valve of the first connecting pipe 8a is closed.

[0068] The third step is to repeat the operations of the first and second steps on another grouting section. After grouting has been performed on all grouting sections and the connecting pipes have been closed, grouting continues to be injected into the pressure-controlled grouting pipe 14 until the grout flows out from the overflow pipe 15. In this embodiment, grout is injected into the second grouting pipe 7b, the third grouting pipe 7c and the fourth grouting pipe 7d in sequence. The operations of the first and second steps are repeated until all the connecting pipe gate valves 13 are closed. Then, grouting continues to be injected into the pressure-controlled grouting pipes 14 set on the first grouting pipe 7a, the second grouting pipe 7b, the third grouting pipe 7c and the fourth grouting pipe 7d until the grout flows out from the overflow pipe 15 of each pressure-controlled grouting pipe 14.

[0069] In this embodiment, the opening and closing of the grouting pipe 7 and the connecting pipe 8 are controlled by a gate valve. However, in other embodiments, the opening and closing of the grouting pipe 7 and the connecting pipe 8 can also be controlled by a rubber plug or other means.

[0070] S8, Vibration Exhaust

[0071] After filling the grouting cavity with grout using the three steps in step S7, insert a hand-held vibrator into the top of any grouting pipe 7. After the vibrator vibrates for 5-10 minutes, add a small amount of grout through other grouting pipes 7. Stop vibrating once water overflows from the pressure overflow hole of the grouting pipe 7 with the vibrator inserted. Then, repeat the above operation with other grouting pipes 7 until the operation is completed at all grouting pipes 7. By sequentially inserting the vibrator into the grouting pipes 7 and vibrating to expel a small amount of residual gas, it is ensured that the grout fills the grouting cavity at the bottom of the precast component tightly.

[0072] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for bottom grouting of underwater precast components, comprising a pressure-controlled grouting process, characterized in that, During the controlled pressure grouting process, drainage and air are carried out through a grouting pipe connected to the grouting cavity and a connecting pipe that is separate from the grouting pipe but connected to the grouting cavity. During pressure-controlled grouting, the grouting pressure is controlled by a pressure-controlled grouting pipe and an overflow pipe located on the side of the pressure-controlled grouting pipe and connected to it. This ensures the sealing effect of the sealant at the bottom of the precast component and that the grout can fill the grouting cavity. The height of the connection between the overflow pipe and the pressure-controlled grouting pipe from the bottom of the precast component is [missing information]. ,in, , The mass of the precast component is expressed in tons (t). The base area of ​​the precast component is expressed in m². 2 , The density of the slurry is expressed in t / m³. 3 .

2. The underwater precast component bottom grouting method as described in claim 1, characterized in that, During the drainage and venting process through the connecting pipe and grouting pipe, ensure that the lower ends of the connecting pipe and grouting pipe are flush with the lower surface of the precast component base plate.

3. The underwater precast component bottom grouting method as described in claim 1, characterized in that, Before the pressure-controlled grouting process, an air venting pipe for venting air and water from the grouting cavity is installed inside the sealing part. One end of the air venting pipe is located inside the connecting pipe, and the other end is located in the grouting cavity on the side farther from the connecting pipe.

4. The underwater precast component bottom grouting method as described in claim 3, characterized in that, The air intake pipe is fixed to the lower surface of the precast component base plate.

5. The underwater precast component bottom grouting method as described in claim 1, characterized in that, The grout is made by mixing 32.5R early-type silicate cement with water, and the water-cement ratio is 0.5:

1.

6. The underwater precast component bottom grouting method as described in claim 1, characterized in that, The following steps are used for step-by-step grouting during pressure-controlled grouting: The first step is to open any one of the gate valves of the grouting pipe and the gate valve of the connecting pipe closest to that grouting pipe; The second step is to set the pressure-controlled grouting pipe on the open grouting pipe and inject grout. After the grout of the same concentration as the grout overflows from the connecting pipe closest to the grouting pipe, close the gate valve of the connecting pipe to complete the grouting construction of the grouting pipe. The third step is to open the gate valve of another grouting pipe and the gate valve of the connecting pipe closest to the grouting pipe, and repeat the operations of the first and second steps until all grouting pipes have completed the grouting construction.

7. The underwater precast component bottom grouting method as described in claim 6, characterized in that, After the pressure-controlled grouting process is completed, a vibration and air-venting process is also included: after sinking a vibrator into any grouting pipe and vibrating it for 5-10 minutes, a small amount of grout is added from other grouting pipes for supplementary grouting. After water overflows from the pressure-controlled overflow hole of the grouting part that has been submerged in the vibrator, the vibration is stopped. Then, the above operation is repeated with other grouting pipes until the above operation is completed at all grouting parts.

8. The underwater precast component bottom grouting method as described in claim 6 or 7, characterized in that, The pressure-controlled grouting pipe is detachably connected to the grouting pipe.

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