Grouting device and method for effectively enlarging weak permeable stratum reinforcement range

Abstract

The invention discloses a grouting device and method for effectively enlarging the weak permeable stratum reinforcement range, and belongs to the technical field of grouting construction equipment.The grouting device comprises an auxiliary mechanism, the auxiliary mechanism comprises a chassis, a support is arranged on the chassis, an ultrasonic grouting mechanism is arranged on the support, and the ultrasonic grouting mechanism comprises a magnetostrictive transducer; the magnetostriction transducer is communicated with a secondary amplitude intensifier, the magnetostriction transducer is connected with an ultrasonic generator, the ultrasonic generator is connected with a control system, and the secondary amplitude intensifier is communicated with a grouting pump through a one-way valve. Ultrasonic waves are introduced into a grouting system, ultrasonic energy is transmitted through grouting liquid, the effect of grouting while disturbing is achieved, the grouting pressure is controlled within 0.4 MPa, and structural safety is guaranteed.

Description

Technical Field

[0001] This invention belongs to the technical field of grouting construction equipment, and particularly relates to a grouting device and method for effectively expanding the reinforcement range of weakly permeable strata. Background Technology

[0002] During the long-term operation of subway tunnels, the surrounding strata inevitably change due to various factors, leading to various defects in the tunnel structure such as cracks, water seepage, and deformation. These defects seriously affect the normal operation and structural safety of the subway. Grouting to stabilize the strata and improve the interaction between the strata and the tunnel structure is a commonly used method. However, due to the low permeability coefficient of low-permeability surrounding rocks (such as fine sand, clay, and silty clay), the grouting slurry usually cannot diffuse widely along the stratum pores, resulting in a significantly reduced effective improvement area and extremely poor construction results. Currently, three methods are commonly used for grouting: low-pressure slow seepage, reducing grout particle size, or using organic grout and high-pressure fracturing grouting. However, these methods have the following drawbacks in existing subway tunnel construction scenarios:

[0003] (1) Low-pressure slow injection method (pressure is generally less than 0.5MPa): The grouting time is long and the grouting effect is highly random. The grouting time of a single hole exceeds 2 hours, which is difficult to meet the 2-hour window period operation time limit.

[0004] (2) Reducing the particle size of the grout or using organic grout for grouting: By reducing the particle size of the grout or using organic grout for grouting, the diffusion range of the grout in the formation can be effectively increased, and the construction cost increases exponentially.

[0005] (3) High-pressure fracturing grouting (generally greater than 0.5MPa): High-pressure grouting equipment is bulky (400-500 kg), difficult to transport, and excessive pressure may cause secondary damage to the existing tunnel structure, thus limiting its use in existing subway tunnels. Summary of the Invention

[0006] The purpose of this invention is to provide a grouting device and method that can effectively expand the reinforcement range of weakly permeable strata, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: The present invention provides a grouting device for effectively expanding the reinforcement range of weakly permeable strata, including an auxiliary mechanism. The auxiliary mechanism includes a chassis, a support on the chassis, and an ultrasonic grouting mechanism on the support. The ultrasonic grouting mechanism includes a magnetostrictive transducer, which is connected to a secondary amplitude enhancer. The magnetostrictive transducer is connected to an ultrasonic generator, which is connected to a control system. The secondary amplitude enhancer is connected to a grouting pump through a one-way valve.

[0008] Optionally, the grouting pump is connected to one end of a grouting hose, and the other end of the grouting hose is connected to the one-way valve.

[0009] Optionally, the grouting hose is equipped with a flow sensor and a pressure sensor, which are electrically connected to the control system.

[0010] Optionally, a primary amplitude enhancer is provided between the magnetostrictive transducer and the secondary amplitude enhancer.

[0011] Optionally, the secondary amplitude enhancer is provided with a slurry channel and a perforated tube structure.

[0012] Optionally, the one-way valve includes a one-way valve body, the inlet end of which is connected to the grouting hose, a one-way valve core is provided inside the one-way valve body, a return spring is provided on the side of the one-way valve core away from the inlet end, and the outlet end of the one-way valve body is connected to the secondary amplitude enhancer.

[0013] Optionally, the grouting pump is electrically connected to the control system.

[0014] Optionally, the bottom of the chassis is equipped with pulleys.

[0015] A method for using a grouting device that effectively expands the reinforcement range of weakly permeable strata includes the following steps:

[0016] S1. Install the device, connect the ultrasonic generator to the control system, and preset the ultrasonic generator power and grouting pump pressure in the control system. Connect the grouting pump to the secondary amplitude enhancer through the grouting hose.

[0017] S2. Start the ultrasonic grouting structure, and the grouting pump will begin grouting at the preset pressure.

[0018] S3. Start the ultrasonic generator. The ultrasonic generator generates a current of a specific frequency. The current flows to the coil of the magnetostrictive transducer to generate a changing magnetic field. The magnetostrictive oscillator structure inside the magnetostrictive transducer vibrates under the action of the magnetic field. The vibration is transmitted through the slurry passage in the first-stage amplitude enhancer and the second-stage amplitude enhancer, which also play a role in grouting reinforcement.

[0019] S4. After grouting is completed, both the grouting pump and the ultrasonic generator shall be turned off. The device shall be removed after the grout has initially set.

[0020] This invention discloses the following technical advantages: It introduces ultrasonic waves into the grouting system and transmits ultrasonic energy through the grouting fluid, achieving simultaneous grouting and disturbance. The grouting pressure is controlled within 0.4 MPa, ensuring structural safety. The device has a low overall weight and its detachable design improves handling efficiency and reduces labor costs. The grouting diffusion range of this device is 30% greater than that of the low-pressure slow seepage grouting method. Furthermore, ordinary cement grouting fluid can achieve the desired grouting effect, reducing overall costs by 40%. Using ultrafine cement grouting fluid further expands the grouting range while avoiding the cost spikes associated with organic grouting fluids. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a schematic diagram of the grouting device of the present invention, which effectively expands the reinforcement range of weakly permeable strata;

[0023] Figure 2 This is a schematic diagram of the one-way valve of the present invention.

[0024] Figure label:

[0025] 1. Controller; 2. Magnetostrictive transducer; 3. Ultrasonic generator; 4. Grouting pump; 5. First-stage amplitude enhancer; 6. Check valve; 61. Check valve body; 62. Check valve core; 63. Return spring; 64. Inlet end; 65. Outlet end; 7. Second-stage amplitude enhancer; 8. Flow sensor; 9. Grouting hose; 10. Pressure sensor. Detailed Implementation

[0026] Grouting technology, as a traditional and effective method for soil reinforcement and defect treatment, improves the physical and mechanical properties of the soil and restores the balance of structure-soil interaction by injecting grout with cementing, filling, and compacting effects into the soil or structural gaps. It has become the "preferred solution" for the treatment of defects in subway tunnels. However, with the extension of subway service life, increasingly stringent environmental constraints, and higher technical requirements, the limitations of traditional grouting technology in terms of material durability, process precision, and design theory have gradually become apparent, making it difficult to meet the operational-period defect treatment requirements of "high safety, low interference, and long service life".

[0027] The interaction between the subway tunnel structure and the surrounding strata is a dynamic process. The occurrence of defects during operation is essentially the cumulative result of "changes in strata conditions - structural response failure". Its causes can be divided into three categories: natural factors, human factors, and structural factors. These factors are coupled with each other, ultimately leading to visible defects such as cracks, water seepage, and deformation.

[0028] Grouting technology involves injecting grout into the strata or structural fissures. By utilizing the filling, compaction, and bonding effects of the grout, it improves the physical and mechanical properties of the strata (such as increasing strength and reducing permeability) and restores the balance of the interaction between the structure and the strata. It is one of the core technologies for treating defects in subway tunnels.

[0029] (I) Classification and Principles of Grouting Technology

[0030] Based on the purpose of grouting (water plugging, reinforcement, lifting) and the grout material (cement-based, chemical-based), grouting technology can be divided into the following categories:

[0031] Classification by purpose

[0032] Grouting for water plugging: By injecting low-viscosity, high-permeability grout (such as cement-water glass dual-liquid grout, polyurethane chemical grout), the pores of the strata or structural cracks are filled, blocking the seepage path of groundwater. It is suitable for the treatment of seepage problems.

[0033] Grouting reinforcement: By injecting high-concentration cement grout or chemical grout (such as epoxy resin, acrylate), it binds the stratum particles or fills the structural gaps, improving the stratum strength (such as increasing the compressive strength from 0.5MPa to 2.0MPa) or the integrity of the structure. It is suitable for treating cracks and deformation defects.

[0034] Lifting grouting: By injecting expansive grout (such as cement-expansive grout) or controlling the grouting pressure, the settled tunnel structure is lifted to the design elevation. It is suitable for treating settlement defects (such as differential settlement > 20 mm).

[0035] Classification by slurry material

[0036] Cement-based grout: Using cement as the main binder and adding admixtures such as fly ash and slag, it has advantages such as low cost, good durability, and non-toxicity, and is suitable for formation reinforcement and water shut-off; however, it has the disadvantages of relatively coarse particles (particle size > 0.05 mm) and poor permeability (permeability coefficient < 10⁻). 4 It has drawbacks such as slow speed (cm / s), making it difficult to inject into fine-grained formations (such as silt and fine sand).

[0037] Chemical grouts: These are mainly composed of polymer materials (such as polyurethane, acrylate, and epoxy resin). They have advantages such as low viscosity (<100 mPa·s), strong permeability (permeability coefficient >10⁻³ cm / s), and controllable setting time (from a few seconds to tens of minutes). They are suitable for water plugging and crack repair in fine-particle formations. However, they have disadvantages such as high cost (5-10 times that of cement grout), poor durability (such as polyurethane being prone to aging under ultraviolet light), and environmental pollution risks (such as the toxicity of acrylate).

[0038] Composite grout: This type of grout combines cement-based grout with chemical grout (such as cement-water glass two-component grout), taking into account both the economy of cement and the permeability of chemical grout. The setting time (initial setting 30s-5min) can be controlled by adjusting the mix ratio, making it suitable for various geological conditions.

[0039] (II) Grouting process and equipment

[0040] Grouting hole arrangement

[0041] Depending on the type and extent of the damage, grouting holes can be arranged in a "quincunx," "rectangular," or "ring" pattern, with a hole spacing of 1.0-2.0m. The hole depth is determined based on geological conditions (such as soft soil or karst) and the depth of the damage (such as crack depth or settlement range), generally 2-5m below the bottom of the tunnel structure. For seepage damage, holes should be arranged around the seepage point (distance <0.5m); for crack damage, holes should be staggered along both sides of the crack (distance 0.3-0.5m from the crack).

[0042] Grouting parameter control

[0043] Grouting pressure: Determined based on geological conditions (e.g., 0.3-0.5 MPa for soft soil, 0.5-1.0 MPa for karst formations) and structural safety (to avoid structural damage), and is usually adjusted through field tests. Excessive pressure may cause ground uplift or expansion of structural cracks, while insufficient pressure will not effectively fill the gaps.

[0044] Grouting flow rate: Adjust according to the type of grout (cement grout flow rate 50-100L / min, chemical grout flow rate 10-30L / min) and the permeability of the formation. Excessive flow rate may cause grout loss, while insufficient flow rate will affect grouting efficiency.

[0045] Setting time: Controlled by adding accelerators (such as water glass) or retarders (such as phosphates). Water plugging grout requires an initial setting time of <5 min, while reinforcement grout requires an initial setting time of >30 min.

[0046] Grouting equipment

[0047] Traditional grouting equipment includes grouting pumps (such as piston pumps and screw pumps), mixers, and grouting pipes. In recent years, with the development of automation technology, intelligent grouting equipment (such as grouting systems with real-time flow and pressure monitoring) has been gradually applied, enabling dynamic adjustment of grouting parameters and process visualization.

[0048] (III) Application Effects of Grouting Technology

[0049] Grouting technology has accumulated rich experience and achieved remarkable results in the treatment of subway tunnel defects:

[0050] Seepage treatment: Cement-water glass double-liquid grout or polyurethane chemical grout is used for water plugging, with a success rate of 80%-90%, and the seepage volume can be reduced from 10-50m³ / h to <1m³ / h (meeting the requirements of the "Metro Operation Safety Evaluation Standard").

[0051] Crack repair: Cracks (width > 0.2 mm) are filled with epoxy resin or cement-based grout, and the crack closure rate can reach 70%-85%, significantly improving the structural impermeability and integrity.

[0052] Settlement Lifting: Cement-expansion agent grout is used to lift the settlement tunnel. The lifting amount can be controlled within 10-30mm, and the differential settlement can be reduced from 20mm to within 5mm. The track geometry is restored to the design standard.

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Reference Figures 1 to 2 As shown, this embodiment provides a grouting device for effectively expanding the reinforcement range of weakly permeable strata. It includes an auxiliary mechanism, which includes a chassis with a support on the chassis. An ultrasonic grouting mechanism is mounted on the support. The ultrasonic grouting mechanism includes a magnetostrictive transducer 2, which is connected to a secondary amplitude enhancer 7. The magnetostrictive transducer 2 is connected to an ultrasonic generator 3, which is connected to a control system. The secondary amplitude enhancer 7 is connected to a grouting pump 4 through a one-way valve 6.

[0056] The ultrasonic grouting mechanism is connected to the control system. The grouting pressure and ultrasonic excitation frequency are input into the control system, and "start" is clicked. The grouting pump 4 begins to output grout at a stable pressure. Pressure sensor 10 in the control system monitors the grout pressure in the grouting hose 9, and flow sensor 8 monitors the instantaneous flow rate in the grouting pipeline. The intelligent controller 1 determines the grouting progress based on the rate of change of the monitored data and uses an algorithm to determine the grout injection velocity and diffusion range into the formation. When the grout diffusion velocity is below a threshold, the power of the ultrasonic generator 3 is increased to expand the damage area, thereby promoting grout diffusion.

[0057] This invention introduces ultrasonic waves into the grouting system and transmits ultrasonic energy through the grouting fluid, achieving the effect of grouting while simultaneously disturbing the surface. The grouting pressure is controlled within 0.4 MPa, ensuring structural safety. The device has a low total weight, with the prototype weighing less than 100 kg. Its detachable design improves handling efficiency and reduces labor costs. The grouting diffusion range of this device is increased by approximately 30% compared to the low-pressure slow seepage grouting method. Furthermore, ordinary cement grouting fluid can achieve the desired grouting effect, reducing overall costs by approximately 40%. Using ultrafine cement grouting fluid further expands the grouting range while avoiding the cost spikes associated with organic grouting fluids.

[0058] The scheme was further optimized so that the grouting pump 4 was connected to one end of the grouting hose 9, and the other end of the grouting hose 9 was connected to the one-way valve 6.

[0059] The scheme was further optimized by installing a flow sensor 8 and a pressure sensor 10 on the grouting hose 9, which are electrically connected to the control system.

[0060] Pressure sensor 10 and flow sensor 8 are separate high-precision sensors, fixed at the top of grouting hose 9, and separately connected to intelligent controller 1 to provide real-time feedback of grouting data.

[0061] To further optimize the design, a primary amplitude enhancer 5 is installed between the magnetostrictive transducer 2 and the secondary amplitude enhancer 7.

[0062] The design was further optimized by incorporating a slurry channel and a perforated tube structure in the secondary amplitude enhancer 7.

[0063] The ultrasonic generator 3 and the magnetostrictive vibrator emit ultrasonic waves, which are amplified by a dual-stage amplifier. The grouting fluid is used as the ultrasonic wave propagation carrier. The ultrasonic waves cause the air nuclei in the grout to cavitate. The pressure generated by the rupture of the air nuclei breaks the valence bonds of soil molecules, greatly expanding the micro-cracks in the soil and promoting the large-scale diffusion of the grout in the soil.

[0064] Further optimization of the scheme: the one-way valve 6 includes a one-way valve body 61, the inlet end 64 of the one-way valve body 61 is connected to the grouting hose 9, the one-way valve body 61 is provided with a one-way valve core 62, the one-way valve core 62 is provided with a reset spring 63 on the side away from the inlet end 64, and the outlet end 65 of the one-way valve body 61 is connected to the secondary amplitude enhancer 7.

[0065] The slurry enters the one-way valve 6 through the inlet end 64 of the one-way valve body 61, pushing the one-way valve core 62 and compressing the reset spring 63. In this way, the slurry flow channel is opened, and the slurry can be injected into the soil through the outlet end 65 via the secondary amplitude enhancer 7.

[0066] The scheme was further optimized by electrically connecting the grouting pump 4 to the control system.

[0067] The design has been further optimized by installing pulleys at the bottom of the chassis.

[0068] The pulleys are fixed to the chassis, allowing the entire device to move easily along the subway tracks. The support frame uses a plug-in structure, enabling quick on-site assembly, disassembly, and reassembly, reducing the difficulty of manual handling and improving work efficiency. The control system and ultrasonic grouting mechanism are mounted on the support frame.

[0069] A method for using a grouting device that effectively expands the reinforcement range of weakly permeable strata includes the following steps:

[0070] S1. Install the device, connect the ultrasonic generator 3 to the control system, and preset the power of the ultrasonic generator 3 and the pressure of the grouting pump 4 in the control system. Connect the grouting pump 4 to the secondary amplitude enhancer 7 through the grouting hose 9.

[0071] S2. Start the ultrasonic grouting structure, and grouting pump 4 starts grouting at the preset pressure;

[0072] S3. Start the ultrasonic generator 3. The ultrasonic generator 3 generates a specific frequency current, which flows to the coil of the magnetostrictive transducer 2 to generate a changing magnetic field. The magnetostrictive oscillator structure inside the magnetostrictive transducer 2 vibrates under the action of the magnetic field, and the vibration is transmitted through the primary amplitude enhancer 5 and the secondary amplitude enhancer 7, which contain grout passages and simultaneously play a role in grouting reinforcement. The secondary amplitude enhancer 7 contains grout channels and a perforated tube structure, which can also act as a grouting gun head. The ultrasonic waves are transmitted to the grouting fluid through the enhancement. When the ultrasonic waves propagate in the liquid, they can act on the gas mixed in the liquid, causing the bubbles to continuously expand and shrink until the surface tension of the liquid on the bubble surface exceeds the surface tension of the liquid, and the bubble bursts. The bursting instant generates huge pressure and temperature. The above process is called cavitation. The cavitation of the grout continuously expands the soil pores in the area through which the grouting fluid flows, turning micro-pores into small pores, and small pores into large pores, thus loosening the soil and facilitating subsequent grout injection and flow, thereby achieving the purpose of expanding the grouting range.

[0073] S4. After grouting is completed, simultaneously shut down grouting pump 4 and ultrasonic generator 3, and remove the device after the grout has initially set.

[0074] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0075] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A grouting device for effectively expanding the reinforcement range of weakly permeable strata, characterized in that: The system includes an auxiliary mechanism, which includes a chassis with a support on the chassis and an ultrasonic grouting mechanism on the support. The ultrasonic grouting mechanism includes a magnetostrictive transducer (2), which is connected to a secondary amplitude enhancer (7). The magnetostrictive transducer (2) is connected to an ultrasonic generator (3), which is connected to a control system. The secondary amplitude enhancer (7) is connected to a grouting pump (4) through a one-way valve (6).

2. The grouting device for effectively expanding the reinforcement range of weakly permeable strata according to claim 1, characterized in that: The grouting pump (4) is connected to one end of the grouting hose (9), and the other end of the grouting hose (9) is connected to the one-way valve (6).

3. The grouting device for effectively expanding the reinforcement range of weakly permeable strata according to claim 2, characterized in that: The grouting hose (9) is equipped with a flow sensor (8) and a pressure sensor (10), which are electrically connected to the control system.

4. The grouting device for effectively expanding the reinforcement range of weakly permeable strata according to claim 1, characterized in that: A primary amplitude enhancer (5) is provided between the magnetostrictive transducer (2) and the secondary amplitude enhancer (7).

5. The grouting device for effectively expanding the reinforcement range of weakly permeable strata according to claim 1, characterized in that: The secondary amplitude enhancer (7) is equipped with a slurry channel and a flower tube structure.

6. The grouting device for effectively expanding the reinforcement range of weakly permeable strata according to claim 2, characterized in that: The one-way valve (6) includes a one-way valve body (61), the inlet end (64) of the one-way valve body (61) is connected to the grouting hose (9), the one-way valve body (61) is provided with a one-way valve core (62), the one-way valve core (62) is provided with a return spring (63) on the side away from the inlet end (64), and the outlet end (65) of the one-way valve body (61) is connected to the secondary amplitude enhancer (7).

7. The grouting device for effectively expanding the reinforcement range of weakly permeable strata according to claim 1, characterized in that: The grouting pump (4) is electrically connected to the control system.

8. The grouting device for effectively expanding the reinforcement range of weakly permeable strata according to claim 1, characterized in that: The chassis is equipped with pulleys at the bottom.

9. A method for using a grouting device for effectively expanding the reinforcement range of weakly permeable strata, based on the grouting device for effectively expanding the reinforcement range of weakly permeable strata as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Install the device, connect the ultrasonic generator (3) to the control system, and preset the power of the ultrasonic generator (3) and the pressure of the grouting pump (4) in the control system. Connect the grouting pump (4) to the secondary amplitude enhancer (7) through the grouting hose (9). S2. Start the ultrasonic grouting structure, and the grouting pump (4) starts grouting at the preset pressure; S3. Start the ultrasonic generator (3). The ultrasonic generator (3) generates a specific frequency current. The current flows to the coil of the magnetostrictive transducer (2) to generate a changing magnetic field. The magnetostrictive oscillator structure inside the magnetostrictive transducer (2) vibrates under the action of the magnetic field. The vibration is transmitted through the slurry passage in the first-stage amplitude enhancer (5) and the second-stage amplitude enhancer (7) to play the role of grouting enhancement. S4. After the grouting is completed, the grouting pump (4) and the ultrasonic generator (3) are turned off at the same time. After the grout has initially set, the device is removed.

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