Device and method for waterproof construction of diaphragm wall joint by using magnetic slurry

Abstract

The invention relates to the technical field of joint waterproofing of underground diaphragm walls, and provides a device and a method for joint waterproofing by using magnetic slurry. The device comprises a double-liquid grouting machine, a grouting pipe, a magnet and a lifting mechanism. According to the method, a magnetic field is formed at a seam through a magnet, magnetic slurry is directionally gathered under the action of the magnetic field, solidification is accelerated in cooperation with a water glass solution, and the water flow scouring influence is reduced. The magnetic slurry is prepared from quick-hardening sulphoaluminate cement, magnetic powder, water-borne epoxy resin and the like according to a specific proportion, and has high dispersion resistance and flowability. The device adopts double-pipe grouting, the magnet can be lifted and recycled, and the T-shaped partition plate enhances the stability of the magnetic field. Construction is easy and convenient, the material cost is low, joints can be accurately filled, bubbles can be discharged, the waterproof effect and the joint strength are remarkably improved, and the later leakage risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of waterproof construction of diaphragm walls, and particularly to a device and method for waterproof construction of diaphragm wall joints using magnetic slurry. Background Technique

[0002] A diaphragm wall is a continuous reinforced concrete wall formed by segmental construction in foundation engineering, which is used for water cutoff, seepage prevention, load bearing and water retaining. The waterproof treatment at its joints is a difficult point in engineering quality. If the waterproof treatment of the diaphragm wall is not proper, it will directly affect the construction quality of the whole project. This may lead to various problems during the later use of the project, such as wall cracking, leakage, etc., bringing great inconvenience to use and maintenance. Its waterproof performance is directly related to the safety of the foundation pit. The traditional method uses ordinary concrete grouting, but there are the following problems: 1. Groundwater flow scours the unhardened concrete, causing material loss and poor waterproof effect; 2. Ordinary grouting is prone to generate bubbles and voids, the joint filling is uneven, and the later leakage risk is high; 3. Ordinary cement has a slow setting speed and low early strength, and it is difficult to resist the dynamic water pressure; 4. It relies on manual operation or high-cost equipment, with low efficiency and difficult to accurately control the grouting process.

[0003] Therefore, a device and method for waterproof construction of diaphragm wall joints using magnetic slurry are proposed to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above deficiencies and provide a device and method for waterproof construction of diaphragm wall joints using magnetic slurry to solve the problems raised in the background technique.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: A device for waterproof construction of diaphragm wall joints using magnetic slurry, including: a dual-liquid grouting machine, which includes an independently arranged magnetic slurry storage tank and a sodium silicate solution storage tank, and realizes the synchronous transportation of the two slurries through a dual-pipe grouting system; a grouting pipe, whose slurry outlet is connected to a lift through a mechanical linkage device to ensure the same lifting rate; a magnet, made of permanent magnetic material, fixed on the outer edge of the slurry outlet of the grouting pipe; a PVC pipe, vertically installed at the center position of the joint, used to guide the magnetic slurry to fill along the axial direction of the joint.

[0006] Preferably, the dual-liquid grouting machine includes: a mixing barrel, with a pneumatic mixer inside, used to mix the components of the magnetic slurry; a sodium silicate solution storage tank, storing a sodium silicate solution with a concentration of 60%, connected to the grouting pipe through an independent pipeline; the volume ratio of the magnetic slurry to the sodium silicate solution is 3:1, and the gelation time after mixing is ≤ 30 seconds.

[0007] Preferably, the lift is a hydraulic-driven lifting device, and the magnet is fixed by a detachable hook; the magnetic field strength of the magnet ranges from 0.5T to 1.5T, which is used to form a directional magnetic field at the joint. The horizontal distance between the magnet and the slurry outlet of the grouting pipe is ≤10mm to ensure that the magnetic field covers the grouting area.

[0008] Preferably, the components and proportions of the magnetic slurry are as follows: rapid-hardening sulphoaluminate cement: accounting for 50%-60% of the total mass; magnetic powder: dosage 20%, particle size 5-10μm; water-based epoxy resin emulsion: epoxy resin A dosage 3%, curing agent B dosage 2.5%; water reducer: dosage 0.2%; flocculant: dosage 1.5%; water-cement ratio: 0.35.

[0009] Preferably, the specific performance of the magnet needs to meet: temperature resistance range: -273°C to 300°C; magnetic saturation intensity ≥1.2T; surface nickel-plated treatment, corrosion resistance grade ≥IP68.

[0010] Preferably, the diameter of the PVC pipe is 50-100mm. After grouting is completed, the internal voids are filled with concrete of strength grade C30 and above; the pressure grouting method is used when filling the concrete to ensure that the bond strength with the joint is ≥2MPa.

[0011] Preferably, the T-shaped partition board has the following structure: magnetic surface: a second magnet is embedded on one side, and the magnet spacing is ≤50mm; non-magnetic surface: made of ordinary concrete board, with a thickness of 1.2-1.5 times the joint width; during installation, the magnetic surface faces the joint direction, and the non-magnetic surface is embedded in the diaphragm wall.

[0012] Preferably, the second magnets on the magnetic surface are evenly distributed in a matrix, and the magnetic field coverage range is 2-3 times the joint width.

[0013] In addition, the present invention also discloses a method for using a device for waterproof construction of the diaphragm wall joint with magnetic slurry, including the following steps: Step 1: Clean the surface of the joint, and use a high-pressure water gun to remove impurities; Step 2: Detect the width, depth and trend of the joint through a flaw detector to determine the installation position of the PVC pipe; Step 3: Prepare the magnetic slurry according to the ratio of claim 4, and dilute the water glass to a concentration of 60%; Step 4: Use the lift to vertically fix the PVC pipe at the center of the joint, with an error ≤5mm; Step 5: Start the double-fluid grouting machine and inject the magnetic slurry and the water glass solution synchronously at a pressure of 0.5-1.0MPa; Step 6: During the grouting process, after every 30cm filling height is completed, lift the magnet to the next grouting section through the lift; Step 7: After grouting is completed, remove the magnet, pour concrete into the PVC pipe and cure for 7 days; Step 8: Use a leakage detector to monitor the waterproof effect of the joint, and the leakage rate ≤ 0.1 L / m²·h.

[0014] Preferably, when using a non-permanent magnet, the following additional steps are performed: Embed concrete blocks containing iron powder in the PVC pipe, and the iron powder content is 15%-20%; Use a magnetizer to apply a pulsed magnetic field to the concrete block, with a strength ≥ 0.8 T and a duration ≥ 10 s to form a temporary magnetic field; After grouting is completed, turn off the magnetizer, and the magnetic field decays naturally.

[0015] The present invention has the following beneficial effects: The present invention significantly improves the reliability of the waterproofing of the diaphragm wall joint, reduces the risk of later leakage, and at the same time realizes low-cost and high-efficiency construction through material and process innovation, and is applicable to high-water-pressure environments such as deep foundation pits and underground projects. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the double-tube grouting equipment involved in the present invention; Figure 2 It is a schematic diagram of the samarium-cobalt magnet involved in the present invention; Figure 3 It is a schematic diagram of the elevator in the present invention; Figure 4 It is a schematic diagram when the double-wheel milling machine constructs the diaphragm wall in the present invention; Figure 5 It is a schematic diagram of the T-shaped plate in the present invention; Figure 6 It is a schematic diagram of the magnetic surface of the T-shaped plate in the present invention; Figure 7 It is a schematic diagram of the partition of the T-shaped plate in the present invention; Figure 8 It is a schematic diagram of the magnetizer in the present invention; Figure 9 It is a schematic diagram of the overall grouting construction in the present invention. Detailed Embodiments

[0017] The present invention will be further described below in conjunction with the drawings and embodiments: See Figures 1 to 9, A device for waterproof construction of diaphragm wall joints using magnetic slurry, comprising: a dual-liquid grouting machine 3, including an independently arranged magnetic slurry storage tank and a sodium silicate solution storage tank, and realizing the synchronous transportation of the two slurries through a double-pipe grouting system; a grouting pipe 5, whose slurry outlet is connected to a lift 11 through a mechanical linkage device to ensure the same lifting rate; a magnet 10, made of a permanent magnet material, fixed to the outer edge of the slurry outlet of the grouting pipe 5; a PVC pipe 2, vertically installed at the center of the joint, used to guide the magnetic slurry 4 to fill along the axial direction of the joint. The dual-liquid grouting machine 3: uses a pneumatic dual-liquid grouting pump of model ZJB-30, including two independent storage tanks: a magnetic slurry storage tank and a sodium silicate storage tank; the magnetic slurry storage tank: with a capacity of 200L, equipped with a pneumatic stirrer with a rotation speed of 200rpm, used to mix components such as sulfoaluminate cement, magnetic powder, and epoxy resin; the sodium silicate storage tank: with a capacity of 70L, stores sodium silicate solution pre-diluted to a concentration of 60%, and is connected to the grouting pipe through a corrosion-resistant pipeline; the dual-liquid is transported to channels A and B of the grouting pipe 5 through independent pipelines, and the slurry and sodium silicate are quickly mixed through a static spiral mixer at the outlet; the grouting pipe 5 is made of stainless steel, with an outer diameter of 50mm, and an adjustable nozzle is installed at the slurry outlet, with a pore diameter of 10-15mm; the lift 11 is hydraulically driven, with a stroke of 5m and a lifting rate of 0.1m / s, and is rigidly connected to the grouting pipe 5 through a gear-rack mechanism to ensure that the synchronous lifting error ≤2mm; the magnet 10: uses a samarium cobalt magnet of model SmCo-28, with dimensions of 100×50×20mm, surface nickel-plated, with a thickness of 50μm, and the magnetic field strength of a single magnet is 1.2T; the magnet 10 is arranged in a circular array on the outer edge of the slurry outlet of the grouting pipe 5, with a spacing of 50mm, and is fixed by epoxy resin glue to form an oriented magnetic field with a coverage radius of 300mm; the PVC pipe 2: is made of UPVC, with an outer diameter of 80mm and a wall thickness of 5mm, is vertically inserted into the center of the joint, and the depth is the same as the length of the joint; a laser locator is used for calibration during installation to ensure that the deviation from the joint axis ≤3°.

[0018] Preferably, the two-component grouting machine 3 includes: a mixing barrel 1 with a built-in pneumatic mixer 6 for mixing the components of the magnetic grout 4; a sodium silicate solution storage tank 9 storing a sodium silicate solution 12 with a concentration of 60%, which is connected to the grouting pipe 5 through an independent pipeline; the volume ratio of the magnetic grout 4 to the sodium silicate solution 12 is 3:1, and the gelling time after mixing is ≤ 30 seconds. The ratio of the magnetic grout 4 to the sodium silicate solution 12: magnetic grout flow rate: 3 L / min, sodium silicate solution flow rate: 1 L / min, and the volume ratio is strictly controlled at 3:1; the gelling time after mixing is controlled by adjusting the sodium silicate concentration, 60 ± 2%, and the measured setting time is 25 - 30 seconds; the feeding sequence in the mixing barrel 1: first add water with a water-cement ratio of 0.35, and then sequentially add sulfoaluminate cement, magnetic powder, water reducer, flocculant, and epoxy resin emulsion, and the mixing time is ≥ 5 minutes; dilution operation in the sodium silicate solution storage tank 9: mix the stock solution and water in a volume ratio of 2:3, and quantitatively control it with an electromagnetic flowmeter.

[0019] Preferably, the elevator 11 is a hydraulic-driven lifting device, and the magnet 10 is fixed by a detachable hook; the magnetic field intensity range of the magnet 10 is 0.5 T to 1.5 T, which is used to form a directional magnetic field at the joint. The horizontal distance between the magnet 10 and the outlet of the grouting pipe 5 is ≤ 10 mm to ensure that the magnetic field covers the grouting area. Hydraulic elevator 11: rated load 200 kg, equipped with a displacement sensor with an accuracy of 0.1 mm to real-time feedback the positions of the magnet 10 and the grouting pipe 5; the hook is made of 304 stainless steel and is connected to the magnet 10 through bolts, and the disassembly time is ≤ 30 seconds. The distance between the magnet 10 and the outlet of the grouting pipe 5 is locked at 8 mm by adjusting the bracket to ensure that the magnetic field covers the grouting area.

[0020] Preferably, the components and ratios of the magnetic grout 4 are as follows: Quick-setting sulfoaluminate cement: accounting for 50% - 60% of the total mass; magnetic powder: dosage 20%, particle size 5 - 10 μm; water-based epoxy resin emulsion: epoxy resin A dosage 3%, curing agent B dosage 2.5%; water reducer: dosage 0.2%; flocculant: dosage 1.5%; water-cement ratio: 0.35. Taking 1 m³ of grout as an example, the specific ratio is: Quick-setting sulfoaluminate cement P.O42.5: 550 kg; magnetic powder selected as Fe3O4 with a particle size of 5 - 10 μm, 220 kg, dosage 20%; water-based epoxy resin emulsion with a solid content of 50%: 66 kg, including epoxy resin A 3% + curing agent B 2.5%; water reducer selected as Sika 325C: 1.1 kg, dosage 0.2%; flocculant selected as polyacrylamide: 16.5 kg, dosage 1.5%; water: 192.5 kg, water-cement ratio 0.35. Feed the materials into the mixing barrel in sequence, and the pneumatic mixer runs at 200 rpm for 5 minutes, and the measured fluidity is ≥ 260 mm.

[0021] Preferably, the specific performance of the magnet 10 should meet the following requirements: temperature resistance range: -273°C to 300°C; magnetic saturation intensity ≥ 1.2T; surface nickel plating treatment, corrosion resistance level ≥ IP68.

[0022] Preferably, the diameter of the PVC pipe 2 is 50 - 100mm. After grouting is completed, the internal voids are filled with concrete of strength grade C30 or above. The pressure grouting method is used during concrete filling to ensure that the bonding strength with the joint is ≥ 2MPa. Concrete pouring: The material selected is C35 slightly expanded concrete with an expansion rate of 0.02% - 0.04%. It is injected into the PVC pipe 2 through a pressure grouting machine after the pressure is adjusted to 0.8MPa. The curing conditions are a temperature of 20 ± 5°C and a humidity of ≥ 90%. After 7 days of curing, the compressive strength is ≥ 35MPa. After curing is completed, a pull-out tester is used to detect the bonding strength between the joint and the concrete, which is required to be ≥ 2MPa.

[0023] Preferably, the T-shaped partition board 13 has the following structure: Magnetic surface 16: The second magnet 18 is embedded on one side, and the magnet spacing ≤ 50mm; Non-magnetic surface: An ordinary concrete board is used, with a thickness 1.2 - 1.5 times the joint width; During installation, the magnetic surface 16 faces the joint direction, and the non-magnetic surface is embedded in the diaphragm wall. The T-shaped partition board 13 can have a total height of 1.2m, a horizontal wing plate width of 300mm, and a vertical web thickness of 100mm. The second magnet 18 is embedded on the magnetic surface 16. Samarium cobalt magnets can be selected, with dimensions of 50 × 50 × 10mm, and a spacing of 50mm in a checkerboard pattern. After the double-wheel milling trench is formed, the partition board 13 is immediately pressed into the uncured concrete, with the magnetic surface 16 facing the joint 1, and the non-magnetic surface is connected to the diaphragm wall through anchor bars Φ12mm.

[0024] Preferably, the second magnets 18 on the magnetic surface 16 are evenly distributed in a matrix. The magnetic field coverage range is 2 - 3 times the joint width. Using magnetic field simulation software such as COMSOL for analysis, when the spacing of the second magnets 18 ≤ 50mm, the magnetic field intensity at a joint width of 100mm is ≥ 0.5T, meeting the requirement for slurry aggregation.

[0025] In addition, the present invention also discloses a method for using a device for waterproof construction of diaphragm wall joints using magnetic slurry, including the following steps: Step 1: Clean the joint surface and remove impurities using a high-pressure water gun; Step 2: Detect the width, depth, and orientation of the joint through a flaw detector to determine the installation position of the PVC pipe 2; Step 3: Prepare the magnetic slurry 4 according to the ratio of claim 4, and dilute the water glass to a concentration of 60%; Step 4: Use the elevator 11 to vertically fix the PVC pipe 2 at the center of the joint with an error ≤ 5 mm; Step 5: Start the double-fluid grouting machine 3 and simultaneously inject the magnetic slurry 4 and the sodium silicate solution 12 at a pressure of 0.5 - 1.0 MPa; Step 6: During the grouting process, after every 30 cm of filling height is completed, lift the magnet 10 to the next grouting section through the elevator 11; Step 7: After the grouting is completed, remove the magnet 10, pour concrete into the PVC pipe 2 and cure for 7 days; Step 8: Use a leakage detector to monitor the waterproof effect of the joint with a leakage rate ≤ 0.1 L / m²·h.

[0026] Preferably, when using a non-permanent magnet, perform the following additional steps: Embed concrete blocks containing iron powder in the PVC pipe 2 with an iron powder content of 15% - 20%; Apply a pulsed magnetic field to the concrete blocks using a magnetizer with a strength ≥ 0.8 T and a duration ≥ 10 s to form a temporary magnetic field; After the grouting is completed, turn off the magnetizer and the magnetic field decays naturally. Generation of the temporary magnetic field: Embed concrete blocks containing iron powder in the PVC pipe 2 with dimensions of 200×200×200 mm and an iron powder content of 18%; Use a pulsed magnetizer, model HC - 50A, to apply a magnetic field to the concrete blocks with a strength of 1.0 T, a pulse width of 15 s, and the magnetic field should be maintained for ≥ 2 hours after magnetization; After the grouting is completed, turn off the magnetizer 19, and the magnetic field decays naturally to ≤ 0.1 T within 24 hours to avoid interfering with the surrounding structures.

[0027] The above embodiments are only the preferred technical solutions of the present invention and should not be regarded as limitations to the present invention. The protection scope of the present invention should be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An apparatus for waterproof construction of diaphragm wall joints using magnetic slurry, characterized in that Comprising: A two - liquid grouting machine (3), including an independently arranged magnetic slurry storage tank and a sodium silicate solution storage tank, and realizing the synchronous transportation of two kinds of slurries through a double - pipe grouting system; A grouting pipe (5), whose slurry outlet is connected to a lift (11) through a mechanical linkage device to ensure the same lifting rate; A magnet (10), made of permanent magnetic material, fixed on the outer edge of the slurry outlet of the grouting pipe (5); A PVC pipe (2), vertically installed at the center position of the joint, used to guide the magnetic slurry (4) to fill along the axial direction of the joint.

2. The device for waterproof construction of diaphragm wall joints using magnetic slurry according to claim 1, characterized in that: The two - liquid grouting machine (3) includes: A mixing barrel (1), with a pneumatic mixer (6) inside, used to mix the components of the magnetic slurry (4); A sodium silicate solution storage tank (9), storing a sodium silicate solution (12) with a concentration of 60%, connected to the grouting pipe (5) through an independent pipeline; The volume ratio of the magnetic slurry (4) to the sodium silicate solution (12) is 3:1, and the gelling time after mixing is ≤ 30 seconds.

3. The device for waterproof construction of diaphragm wall joints using magnetic slurry according to claim 1, characterized in that: The lift (11) is a hydraulic - driven lifting device, and the magnet (10) is fixed by a detachable hook; The magnetic field intensity range of the magnet (10) is 0.5T to 1.5T, used to form a directional magnetic field at the joint. The horizontal distance between the magnet (10) and the slurry outlet of the grouting pipe (5) is ≤ 10mm to ensure that the magnetic field covers the grouting area.

4. A device for waterproof construction of diaphragm wall joints using magnetic slurry, characterized in that: The components and ratios of the magnetic slurry (4) are as follows: Quick - setting sulphoaluminate cement: accounting for 50% - 60% of the total mass; Magnetic powder: dosage 20%, particle size 5 - 10μm; Water - based epoxy resin emulsion: epoxy resin A dosage 3%, curing agent B dosage 2.5%; Water - reducing agent: dosage 0.2%; Flocculant: dosage 1.5%; Water - cement ratio: 0.

35.

5. The device for waterproof construction of diaphragm wall joints using magnetic slurry according to claim 1, characterized in that: The specific performance of the magnet (10) needs to meet: Temperature resistance range: - 273°C to 300°C; Magnetic saturation intensity ≥ 1.2T; Surface nickel - plating treatment, corrosion - resistance grade ≥ IP68.

6. The device for waterproof construction of diaphragm wall joints using magnetic slurry according to claim 1, characterized in that: The diameter of the PVC pipe (2) is 50 - 100mm. After grouting is completed, the internal voids are filled with concrete of strength grade C30 and above; The pressure grouting method is used when filling the concrete to ensure that the bonding strength with the joint is ≥ 2MPa.

7. An apparatus for waterproof construction of diaphragm wall joints using magnetic slurry, characterized in that: A T - shaped partition board (13), whose structure includes: A magnetic - faced surface (16): with a second magnet (18) embedded on one side, the magnet spacing is ≤ 50mm; A non - magnetic - faced surface: made of ordinary concrete board, with a thickness of 1.2 - 1.5 times the joint width; During installation, the magnetic - faced surface (16) faces the joint direction, and the non - magnetic - faced surface is embedded into the diaphragm wall.

8. The device for waterproof construction of the diaphragm wall joint using magnetic slurry according to claim 7, characterized in that: The second magnets (18) on the magnetic - faced surface (16) are evenly distributed in a matrix, and the magnetic field coverage range is 2 - 3 times the joint width.

9. The usage method of a device for waterproof construction of diaphragm wall joints using magnetic slurry according to any one of claims 1-8, characterized in that, Including the following steps: Step 1: Clean the joint surface, and remove impurities using a high - pressure water gun; Step 2: Detect the width, depth and orientation of the joint through a flaw detector to determine the installation position of the PVC pipe (2); Step 3: Prepare the magnetic slurry (4) according to the ratio of Claim 4, and dilute the sodium silicate to a concentration of 60%; Step 4: Use the elevator (11) to vertically fix the PVC pipe (2) at the center of the joint, with an error ≤ 5 mm; Step 5: Start the double-fluid grouting machine (3) and simultaneously inject the magnetic slurry (4) and the sodium silicate solution (12) at a pressure of 0.5 - 1.0 MPa; Step 6: During the grouting process, after every 30 cm of filling height is completed, lift the magnet (10) to the next grouting section through the elevator (11); Step 7: After the grouting is completed, remove the magnet (10), pour concrete into the PVC pipe (2) and cure for 7 days; Step 8: Use a leakage detector to monitor the waterproof effect of the joint, with a leakage rate ≤ 0.1 L / m²·h.

10. The method of using the device for waterproof construction of diaphragm wall joints using magnetic slurry according to Claim 9, characterized in that: When using a non-permanent magnet, the following additional steps are performed: Embed concrete blocks containing iron powder in the PVC pipe (2), with an iron powder content of 15% - 20%; Apply a pulsed magnetic field to the concrete blocks using a magnetizer, with a strength ≥ 0.8 T and a duration ≥ 10 s to form a temporary magnetic field; After the grouting is completed, turn off the magnetizer, and the magnetic field decays naturally.

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