Grouting hole construction device and construction process

Abstract

This invention relates to the field of foundation reinforcement engineering, specifically to a grouting hole construction device and construction process. It includes: an outer pipe, a rigid tubular component with several sets of grouting openings evenly distributed circumferentially on its wall, the axial distance between adjacent sets of openings being 0.8-1.2m, each set containing 4-6 through holes with a diameter of 8-12mm; an inner pipe, coaxially inserted inside the outer pipe, with grouting holes on its wall corresponding to the grouting openings on the outer pipe, and a grouting pipeline connected to the top of the inner pipe; and a double-plug grouting assembly, consisting of an upper grouting plug and a lower grouting plug that can move axially along the inner pipe, and a rubber sleeve fitted over the outer pipe. This invention, through double sealing and precise positioning, effectively solves the problems of cross-layering, backflow, and grouting blind spots, improving the rate of soil strength compliance after reinforcement; it shortens the operation time through dynamic displacement, increasing the grout utilization rate to over 80%, and is adaptable to variable-length grouting in soft / hard soil layers.

Description

Technical Field

[0001] This invention relates to the field of foundation reinforcement engineering, specifically to a grouting hole construction device and construction process. Background Technology

[0002] Traditional sleeve valve grouting technology has the following key drawbacks:

[0003] 1. Poor sealing reliability: The rubber sleeve lacks a positioning skeleton, and is prone to excessive deformation when the grouting pressure increases, leading to seal failure. The grout cross-layer rate reaches 20%-30%, and the backflow rate exceeds 15%.

[0004] 2. Insufficient positioning accuracy: During on-site assembly, the alignment error of the inner and outer pipe openings is often greater than 1mm, which will lead to the formation of grouting blind spots, resulting in a soil strength variation coefficient greater than 0.25 after reinforcement.

[0005] 3. Low construction efficiency: During the segmented grouting process, it is necessary to repeatedly disassemble and reassemble the grout stop plug, and the relocation time accounts for more than 30% of the total construction time.

[0006] 4. Serious waste of grout: After grouting is completed, the grout remaining in the pipe is directly discarded, with a utilization rate of less than 65%, which also causes environmental pollution.

[0007] Existing technologies only optimize a single aspect and do not form a synergistic innovation of "structure + process", thus failing to fundamentally solve the above problems. Summary of the Invention

[0008] To address the problems of existing technologies, this invention provides a grouting hole construction device.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A grouting hole construction device, comprising the following components:

[0011] The outer tube is a rigid tubular component with several sets of grouting openings evenly distributed along the circumference on the tube wall. The axial distance between two adjacent sets of openings is 0.8-1.2m, and each set contains 4-6 through holes with a diameter of 8-12mm.

[0012] An inner tube is coaxially inserted inside the outer tube. The inner tube has grouting holes on its wall that correspond to the grouting holes in the outer tube. The top of the inner tube is connected to a grouting pipeline.

[0013] The double-plug grout-stopping assembly includes an upper grout-stopping plug and a lower grout-stopping plug that can move axially along the inner pipe, and a rubber sleeve fitted on the outside of the outer pipe.

[0014] Furthermore, the rubber sleeve is made of slurry-swelling rubber with an expansion rate of 150%-200%, and has an internally embedded 1-2mm thick annular metal skeleton to limit the radial expansion range and prevent excessive expansion from damaging the tube.

[0015] Furthermore, the upper and lower grout stop plugs are made of oil-resistant rubber with a Shore hardness of 60-70HA. Under the grouting pressure, they fit tightly against the inner and outer pipe walls, with a sealing pressure ≥3MPa.

[0016] Furthermore, the outer wall of the outer tube is coated with a composite anti-corrosion coating of epoxy zinc-rich primer and polyurethane topcoat, with a coating thickness of 0.3-0.5 mm and a corrosion resistance level of C5.

[0017] The construction process of the grouting hole construction device includes the following steps:

[0018] Step 1, Implantation and Positioning: First, implant the assembled sleeve valve tube into the target soil layer. At this time, the pointed bottom guide head will guide the tube body to enter the soil vertically, ensuring that the verticality error is ≤0.5%.

[0019] Step 2, Double-plug positioning and sealing: Next, move the double-plug grout-stopping assembly and use the upper and lower grout-stopping plugs to seal the gap between the inner and outer pipes, thereby forming an independent grouting zone;

[0020] Step 3, Dynamic Pressure Controlled Grouting: Subsequently, grout is injected through the inner pipe. The grout will penetrate into the reinforced area through the aligned openings of the inner and outer pipes. The grouting pressure can be calculated using the following formula:

[0021]

[0022] in This is the initial pressure for slurry diffusion, ranging from 0.3 to 0.5 MPa. The unit weight of the soil layer is kN / m³. The depth of the grouting section is in meters (m). This is the soil pressure coefficient, with a value ranging from 1.1 to 1.3. The coefficient of friction between the slurry and the pipe wall is 0.2-0.3. The length of the grouting section is in meters (m). For safety margin, a value of 1.2-1.5 is used;

[0023] Real-time monitoring and feedback adjustment: Grouting flow rate is monitored in real time during construction using flow sensors. (Accuracy ±1%), pressure sensor monitors grouting pressure Combined with the formula for slurry diffusion radius Real-time calculation of current diffusion radius Value. When the actual diffusion radius deviates from the design value by more than 5%, the dynamic adjustment mechanism is activated:

[0024] - when Too small (insufficient pressure): According to the formula Increase the grouting pressure, where ΔR is the difference between the design radius and the actual radius;

[0025] - when Too high (pressure too high): Immediately reduce grouting flow rate. Or shorten the grouting time This ensures that the slurry diffusion range is consistent with the design value.

[0026] Step 4, Relocation and Section Change: After grouting is completed, depressurize to shrink the rubber sleeve, move the double plug grouting assembly to the next grouting opening group, and move at a speed of 0.3-0.5 m / min. After relocation, a sealing test is required (no leakage after 5 minutes of pressure holding).

[0027] Step 5, Slurry recycling: After grouting is completed, cleaning fluid is injected through the inner pipe to recycle the residual slurry. The recycled slurry is filtered through a 100-mesh filter, and after adding admixtures, it is reused. The slurry recovery rate is ≥35%.

[0028] The further slurry diffusion radius R is calculated using the following formula to determine the grouting hole spacing:

[0029]

[0030] in The grouting flow rate is expressed in m³ / s. Grouting time, in seconds; The soil permeability coefficient is expressed in m / s. The height of the grouting section is in meters (m). The viscosity of the slurry is expressed in Pa·s.

[0031] After further relocation and segment replacement, the grouting pressure parameters need to be adjusted again. For soft soil layers, short-segment high-frequency grouting with a length of 0.8-1m is used, and for hard soil layers, long-segment low-frequency grouting with a length of 1-1.2m is used.

[0032] Compared with existing technologies, the beneficial effects of the invention are: improved reinforcement quality: double sealing and precise positioning completely solve the problems of cross-layering, backflow and grouting blind spots. After reinforcement by dynamic compaction, the soil strength reaches the design requirements, ensuring that the soil strength compliance rate after reinforcement meets the requirements.

[0033] Improved construction efficiency: Dynamic relocation shortens on-site operation time;

[0034] Cost and environmental advantages: Through full-process control of "recycling - sealing and leak prevention - precise injection - dynamic optimization", the utilization rate of slurry can be increased to more than 80%;

[0035] High adaptability: The variable section length technology is adaptable to complex soil layers and is suitable for a variety of engineering scenarios. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the grouting stage of the present invention.

[0037] Figure 2 This is a schematic diagram of the shifting and segmenting stage of the present invention. Detailed Implementation

[0038] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0039] A grouting hole construction device, comprising:

[0040] The outer tube 1 is a rigid tubular component with several sets of grouting openings evenly distributed along the circumference on the tube wall. The axial distance between two adjacent sets of openings is 0.8-1.2m, and each set contains 4-6 through holes with a diameter of 8-12mm.

[0041] The inner tube 2 is coaxially inserted inside the outer tube 1. The inner tube 2 has grouting holes 21 that correspond to the grouting holes of the outer tube 1. The top of the inner tube 2 is connected to the grouting pipeline.

[0042] The double-plug grout-stopping assembly includes an upper grout-stopping plug 31 and a lower grout-stopping plug 32 that can move along the axial direction of the inner pipe, and a rubber sleeve 33 (one-way expansion ring) fitted on the outside of the outer pipe 1; a pointed bottom guide head (not shown in the figure): fixed to the bottom end of the outer pipe 1, is a conical steel structure with a cone angle of 30°-45°, used to guide the pipe body to be vertically implanted into the soil.

[0043] Precise positioning in grouting hole construction equipment and processes is mainly reflected in the following aspects:

[0044] 1. Precise alignment of inner and outer tube openings

[0045] The inner tube of the device has grouting holes that correspond to the grouting openings in the outer tube, ensuring that the grout can accurately penetrate into the target reinforcement area through the aligned openings and avoiding grouting blind spots caused by misaligned openings. This solves the problem that the alignment error of the inner and outer tube openings is often greater than 1mm during on-site assembly in traditional technologies.

[0046] 2. Verticality control of implantation positioning

[0047] The "implantation and positioning" step in the construction process is clearly defined: the pointed bottom guide head (conical steel structure, cone angle 30°-45°) guides the pipe body to be inserted vertically into the soil, with a verticality error of ≤0.5%, to ensure the accurate implantation position of the pipe body and provide a stable foundation for subsequent grouting.

[0048] 3. Independent zone positioning of the dual-piston assembly

[0049] The double-plug grout-stopping assembly seals the gap between the inner and outer pipes through the upper and lower grout-stopping plugs, forming an independent grouting zone. This enables precise isolation and positioning of specific grouting sections, preventing grout from crossing layers.

[0050] These meticulous designs work together to ensure the accuracy of spatial positioning during grouting, thereby improving the overall reinforcement quality.

[0051] Furthermore, the rubber sleeve 33 is made of slurry-swelling rubber with an expansion rate of 150%-200%, and has an internally embedded 1-2mm thick annular metal skeleton to limit the radial expansion amplitude and prevent excessive expansion from damaging the tube body.

[0052] Furthermore, the upper stop plug 31 and the lower stop plug 32 are made of oil-resistant rubber with a Shore hardness of 60-70HA. Under the action of grouting pressure, they fit tightly against the inner and outer pipe walls, with a sealing pressure ≥3MPa.

[0053] Furthermore, the outer wall of the outer tube 1 is coated with a composite anti-corrosion coating of epoxy zinc-rich primer and polyurethane topcoat, with a coating thickness of 0.3-0.5 mm and a corrosion resistance level of C5.

[0054] The construction process of the grouting hole construction device includes the following steps:

[0055] Step 1, Implantation and Positioning: Implant the assembled sleeve valve tube into the target soil layer, using the pointed bottom guide head to guide the tube body vertically into the soil, with a verticality error not exceeding 0.5%;

[0056] Step 2, Double plug positioning and sealing: Move the double plug tube grout-stopping assembly and use the upper grout-stopping plug 31 and the lower grout-stopping plug 32 to seal the gap between the inner tube 2 and the outer tube 1, forming an independent grouting zone;

[0057] Step 3, Dynamic Pressure Controlled Grouting: Grout is injected through inner pipe 2. The grout permeates into the reinforced area through the aligned openings of inner pipe 2 and outer pipe 1. The grouting pressure is calculated according to the following formula:

[0058]

[0059] in This is the initial pressure for slurry diffusion, ranging from 0.3 to 0.5 MPa. The unit weight of the soil layer is kN / m³. The grouting depth is expressed in meters (m). This is the soil pressure coefficient, with a value ranging from 1.1 to 1.3. The coefficient of friction between the slurry and the pipe wall is 0.2-0.3. The length of the grouting section is in meters (m). For safety margin, a value of 1.2-1.5 is used;

[0060] Step 4, Relocation and Section Change: After grouting is completed, pressure is released to allow the rubber sleeve 33 to contract, and the double-plug grout-stopping assembly is moved to the next grouting opening group at a relocation speed of 0.3-0.5 m / min. A sealing test (pressure held for 5 minutes with no leakage) is required after relocation. The relocation and section change steps in the construction process are as follows: After grouting is completed, pressure is released to allow the rubber sleeve to contract, and the double-plug grout-stopping assembly is moved to the next grouting opening group at a relocation speed controlled at 0.3-0.5 m / min. A sealing test (pressure held for 5 minutes) is required after relocation to ensure independent isolation of the grouting section. This design avoids the cumbersome process of repeatedly disassembling and assembling the grout-stopping plug in traditional technology, significantly shortening the relocation time.

[0061] Step 5, Grout Recycling: After grouting, cleaning fluid is injected through the inner pipe to recover residual grout. After filtration through a 100-mesh filter, admixtures are added for reuse, achieving a grout recovery rate of ≥35%. This process directly reduces the amount of waste grout remaining in the pipe. Combined with dynamic pressure-controlled grouting technology for precise control of grout diffusion range, the grout utilization rate is increased to over 80%.

[0062] The "slurry utilization rate increased to over 80%, with no waste slurry pollution, meeting green construction standards" is mainly reflected in the following aspects:

[0063] 1. Slurry recycling system

[0064] Step 5 in the construction process involves slurry circulation and recovery. This involves injecting cleaning fluid into the inner pipe to recover residual slurry, filtering it through a 100-mesh screen, and then adding admixtures for reuse. The slurry recovery rate is ≥35%. This process directly reduces the amount of waste slurry remaining in the pipe. Combined with dynamic pressure-controlled grouting technology, the slurry diffusion range is precisely controlled, further increasing the utilization rate to over 80%. Dynamic pressure-controlled grouting calculates the grouting pressure using a formula (considering parameters such as soil density, burial depth, and pressure coefficient), and adjusts it according to the differences in soil characteristics.

[0065] For soft soil layers: short-segment long (0.8-1m) high-frequency grouting is used to reduce the single-segment grouting pressure (initial pressure 0.3MPa) and avoid excessive disturbance to the soil layer;

[0066] For hard soil layers: long-section (1-1.2m) low-frequency grouting is employed, with increased grouting pressure (initial pressure 0.5MPa) to ensure effective grout diffusion. After relocation (relocation speed 0.3-0.5m / min), a 5-minute pressure holding test verifies the isolation effect of the section. The pressure is recalculated based on parameters such as the burial depth and soil unit weight of the new grouting section to ensure pressure matches soil conditions. Dynamic pressure control technology, combined with the grout diffusion radius formula (considering grouting flow rate, time, soil permeability coefficient, etc.), avoids excessive grout diffusion due to excessive pressure or insufficient diffusion due to insufficient pressure, thereby reducing ineffective grouting consumption. When the soil permeability coefficient is low (hard soil layer), the diffusion radius is small, requiring increased grouting pressure to expand the diffusion range; when the grout viscosity is high, increased pressure is needed to overcome flow resistance and ensure the design value is achieved. Furthermore, the grout diffusion radius R is calculated using the following formula to determine the grouting hole spacing:

[0067]

[0068] Real-time monitoring and feedback adjustment: Grouting flow rate is monitored in real time during construction using flow sensors. (Accuracy ±1%), pressure sensor monitors grouting pressure Based on the above diffusion radius formula, the current situation can be calculated in real time. Value. When the actual diffusion radius deviates from the design value by more than 5%, the dynamic adjustment mechanism is activated:

[0069] when Too low (insufficient pressure): Increase grouting pressure; when Too high (pressure too high): Immediately reduce grouting flow rate. Or shorten the grouting time This ensures that the slurry diffusion range is consistent with the design value.

[0070] 2. Double sealing reduces slurry leakage.

[0071] Rubber sleeve expands and seals when exposed to grout: The rubber sleeve is made of rubber material that expands when exposed to grout (expansion rate 150%-200%), with an internal ring-shaped metal skeleton to limit excessive expansion, ensuring a tight fit with the soil layer during grouting and preventing grout leakage between layers.

[0072] Double-plug grout-stopping assembly: The upper and lower grout-stopping plugs (made of oil-resistant rubber with a Shore hardness of 60-70HA) fit tightly against the inner and outer pipe walls under grouting pressure, with a sealing pressure ≥3MPa, to prevent grout backflow and waste.

[0073] 3. Precise positioning reduces ineffective grouting.

[0074] The inner and outer pipe openings are precisely aligned (error ≤ 1mm), forming an independent grouting zone with the double-plug assembly. This avoids grouting blind spots caused by opening misalignment, ensuring that all grout acts on the target reinforcement area and reducing ineffective grouting. The specific method to achieve this is as follows:

[0075] The grouting openings for the outer and inner pipes are CNC machined in the factory to ensure that the position, number, and angle of the openings are strictly corresponding. Several sets of grouting openings are evenly distributed circumferentially on the outer pipe wall (each set has 4-6 through holes with a diameter of 8-12mm, and the spacing between adjacent sets is 0.8-1.2m). The inner pipe wall is simultaneously machined with grouting holes that correspond exactly to the positions of the openings on the outer pipe. Through factory pre-assembly, the error of the openings between the inner and outer pipes is ≤1mm.

[0076] To avoid errors caused by manual alignment during on-site assembly (traditional errors are often greater than 1mm), the risk of misalignment of openings is controlled from the source.

[0077] The inner tube is coaxially inserted into the outer tube, and the axial and radial positioning accuracy is ensured by the rigid structure of the tube itself and the positioning devices at both ends (such as the grouting pipe interface at the top and the pointed guide head at the bottom), so as to prevent the opening misalignment caused by the tube body displacement during construction.

[0078] Realization of independent grouting zones formed by dual-plug components

[0079] The dynamic sealing double-plug grout sealing assembly is made of oil-resistant rubber with a Shore hardness between 60 and 70 HA. It includes an upper grout stop plug and a lower grout stop plug that can move axially along the inner tube. Under grouting pressure, the grout stop plugs fit tightly against the inner and outer tube walls, forming a sealing pressure ≥3MPa, effectively creating axial isolation between the inner and outer tubes.

[0080] The radial sealing sleeve of the rubber sleeve is located on the outside of the outer pipe. The rubber sleeve (made of slurry-expanding rubber with an expansion rate of 150%-200%) has a 1-2mm thick annular metal skeleton embedded inside. When grouting, the rubber sleeve expands when it comes into contact with the grout and fits tightly with the soil layer, limiting the radial diffusion of the grout. At the same time, the metal skeleton avoids excessive expansion and damage to the pipe body, forming a radial sealing barrier.

[0081] The dynamic switching of independent grouting sections is achieved by moving the double-plug grouting assembly. The upper and lower grouting plugs can be precisely positioned to the target grouting opening group, and with the radial sealing of the rubber sleeve, a closed, independent grouting section is formed. After grouting is completed, the pressure is released to cause the rubber sleeve to contract, allowing the assembly to be moved to the next section, thus realizing continuous segmented grouting operations.

[0082] Synergistic effect

[0083] The precise alignment of the inner and outer tube openings ensures that the grout can be accurately injected into the target area through the aligned openings, avoiding grouting blind spots; the double sealing of the double plug assembly and the rubber sleeve achieves physical isolation of the grouting area, preventing grout from crossing layers or flowing back. Together, they ensure the accuracy and efficiency of grouting.

[0084] Through the above design, the problem of "slurry utilization rate of less than 65%" in traditional technology is solved, achieving zero waste slurry discharge, which meets the requirements of efficient resource utilization and environmental protection in green construction.

[0085] Furthermore, after the relocation and segment change, the grouting pressure parameters need to be adjusted again. For soft soil layers, short-segment high-frequency grouting with a length of 0.8-1m is used, and for hard soil layers, long-segment low-frequency grouting with a length of 1-1.2m is used.

Claims

1. A device for constructing a grouting hole, characterized by include: The outer tube is a rigid tubular component with several sets of grouting openings evenly distributed along the circumference on the tube wall. The axial distance between two adjacent sets of openings is 0.8-1.2m, and each set contains 4-6 through holes with a diameter of 8-12mm. An inner tube is coaxially inserted inside the outer tube. The inner tube has grouting holes on its wall that correspond to the grouting holes in the outer tube. The top of the inner tube is connected to a grouting pipeline. The double-plug grout-stopping assembly includes an upper grout-stopping plug and a lower grout-stopping plug that can move axially along the inner pipe, and a rubber sleeve fitted on the outside of the outer pipe.

2. The grouting hole construction device according to claim 1, characterized in that: The rubber sleeve is made of slurry-swelling rubber with an expansion rate of 150%-200%. An annular metal skeleton with a thickness of 1-2 mm is embedded inside to limit the radial expansion range and prevent excessive expansion from damaging the tube. 3.The grouting hole construction device according to claim 1, characterized in that: The upper and lower stop plugs are made of oil-resistant rubber with a Shore hardness of 60-70HA and a sealing pressure of ≥3MPa.

4. The grouting hole construction device according to claim 1, characterized in that: The outer wall of the outer tube is coated with a composite anti-corrosion coating of epoxy zinc-rich primer and polyurethane topcoat, with a coating thickness of 0.3-0.5 mm and a corrosion resistance level of C5.

5. A construction process for the grouting hole construction device according to claim 1, characterized in that, Includes the following steps: Step 1, Implantation and Positioning: Implant the assembled sleeve valve tube into the target soil layer, using the pointed bottom guide head to guide the tube body vertically into the soil, with a verticality error not exceeding 0.5%; Step 2, Double-plug positioning and sealing: Move the double-plug grout-stopping assembly to allow the upper and lower grout-stopping plugs to seal the gap between the inner and outer pipes, thereby forming an independent grouting zone; Step 3, Dynamic Pressure Controlled Grouting: Grout is injected through the inner pipe. The grout permeates into the reinforced area through the aligned openings of the inner and outer pipes. The grouting pressure is calculated using the following formula: ； in This is the initial pressure for slurry diffusion, ranging from 0.3 to 0.5 MPa. The unit weight of the soil layer is kN / m³. The depth of the grouting section is in meters (m). This is the soil pressure coefficient, with a value ranging from 1.1 to 1.

3. The coefficient of friction between the slurry and the pipe wall is 0.2-0.

3. The length of the grouting section is in meters (m). For safety margin, a value of 1.2-1.5 is used; Real-time monitoring and feedback adjustment: Grouting flow rate is monitored in real time during construction using flow sensors. (Accuracy ±1%), pressure sensor monitors grouting pressure Real-time calculation of the current slurry diffusion radius formula. Value. When the actual diffusion radius deviates from the design value by more than 5%, the dynamic adjustment mechanism is activated: Step 4, Relocation and Section Change: After grouting is completed, depressurize to shrink the rubber sleeve, move the double plug grouting assembly to the next grouting opening group, and move at a speed of 0.3-0.5 m / min. After relocation, a sealing test is required (no leakage after 5 minutes of pressure holding). Step 5, Slurry recycling: After grouting is completed, cleaning fluid is injected through the inner pipe to recover the residual slurry. After filtration through a 100-mesh filter, additives are added for reuse, and the slurry recovery rate is ≥35%.

6. The construction process according to claim 5, characterized in that: The grout diffusion radius R is calculated using the following formula, which is used to determine the grouting hole spacing: in The grouting flow rate is expressed in m³ / s. Grouting time, in seconds; The soil permeability coefficient is expressed in m / s. The height of the grouting section is in meters (m). The viscosity of the slurry is expressed in Pa·s.

7. The construction process according to claim 2, characterized in that: After relocation and section replacement, the grouting pressure parameters need to be adjusted again. For soft soil layers, short-section high-frequency grouting with a length of 0.8-1m is used, and for hard soil layers, long-section low-frequency grouting with a length of 1-1.2m is used.

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