Method and device for reinforcing deep soft soil foundation by variable magnetic field combined with electro-osmosis

Abstract

This invention provides a method and apparatus for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis. The invention involves arranging electromagnetic and drainage electrodes within the site and controlling the output voltage of the external power supply to the drainage and electromagnetic electrodes to flexibly adjust parameters such as electric field direction, electric field strength, magnetic field strength, magnetic field direction, and intermittent time, ensuring that the electric and magnetic fields are perpendicular in real time. This method can guide and enhance electroosmotic flow, improve drainage channels, coordinate settlement in different areas of the site, improve the drainage performance of deep soil while significantly reducing drainage time and increasing consolidation efficiency.

Description

Technical Field

[0001] This invention relates to the field of foundation treatment technology, specifically to a method and apparatus for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis. Background Technology

[0002] Soft clay foundations are widely distributed along the eastern coastal areas of my country. Land development inevitably involves dealing with this geological condition, which possesses numerous unfavorable engineering properties such as high water content, high compressibility, and high thixotropy. Therefore, appropriate foundation treatment methods must be adopted before construction on such foundations. In practical engineering, commonly used methods include vacuum preloading, slab preloading, and high-pressure jet grouting. These methods are relatively effective for treating coarse-grained soils, but their effectiveness is often less than ideal when treating soft soil foundations with low hydraulic conductivity and high clay content, and they are also costly, time-consuming, and inefficient.

[0003] Electroosmosis is a foundation treatment method that involves inserting electrodes carrying direct current into the soil and using an electric field to cause the cations and anions in the liquid phase of the soil to migrate. Water molecules migrate with the cations to the cathode, thereby accelerating the drainage and consolidation of soft soil foundations. The drainage efficiency is independent of the size of soil particles and is considered an ideal method for treating fine-grained soils with low bearing capacity, low permeability, high water content, and high compressibility, which has attracted widespread attention. Scholars at home and abroad have been trying to apply it to practical engineering, but it has not been widely promoted so far. The root cause is that it has many drawbacks in practical applications, as follows: (1) Uneven settlement after treatment. In the later stage of electroosmosis, the current is small and the drainage efficiency is low. A large number of cations in the soil have already carried polar water molecules to the cathode and remained there under the action of the electric field, resulting in excessively high water content in the area near the cathode and excessively low water content in the anode; (2) The treatment effect of deep soil is not ideal. The deep soil has low porosity and poor electrical conductivity. The potential gradually decreases as it is transmitted along the electrode plate to the deep soil. For deep soft soil, the current passing through the deep soil is small, resulting in poor electroosmosis effect. (3) Low energy utilization. The main reason for the large energy consumption of electroosmosis is that the energy utilization is not high when the power is turned on, the effective contact between the electrode and the soil deteriorates, and the power supply is continuously supplied for a long time when the electroosmosis efficiency is low.

[0004] Currently, some scholars have proposed a combined vacuum / electroosmosis / magnetic field / surcharge preloading reinforcement method (patent number: CN102995620A). This method only utilizes magnetic treatment technology to reduce water viscosity, still requiring vacuum, surcharge, and electroosmosis methods for drainage. Therefore, the construction process is cumbersome, costly, and energy-intensive, and it does not achieve the "1+1>2" effect, hindering the widespread application of electromagnetic combined treatment for consolidation and drainage of deep soft soil foundations. In addition, scholars have proposed various improvement schemes, such as air pressure fracturing to enhance electroosmotic drainage, adding chemical solutions, and using new electrode materials. However, these are limited by cumbersome construction procedures, expensive equipment and materials, and poor treatment results, and have not been used in practical engineering. In summary, the electroosmosis method suffers from problems such as uneven soil consolidation, excessive energy consumption, and unsatisfactory treatment effects in deep soils. Current improvement methods have not effectively addressed the many drawbacks of the electroosmosis method, necessitating technological improvements to solve these problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method and apparatus for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis, which is simple to operate and has high drainage efficiency.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis includes:

[0008] Electromagnetic poles and drainage electrodes are laid out in the field; the electromagnetic poles include a protective tube, an inner tube fixed inside the protective tube and an extension rod, and an outer protective cover set on the top of the protective tube. The extension rod consists of a built-in iron rod and an internal conductor coil wound in a fixed direction around the built-in iron rod; multiple extension rods are vertically fixed on the outer circumference of the inner tube; according to the principle of electromagnetism, the current-carrying conductor coil will generate magnetism, and the magnetic field strength is enhanced by the built-in iron rod to form the required vertical variable magnetic field in the field.

[0009] Variable magnetic field combined with electroosmosis treatment: When an electromagnetic electrode and a drainage electrode are energized, the drainage electrode generates an electric field, and the electromagnetic electrode generates a magnetic field that is parallel to the horizontal plane of the site and perpendicular to the electric field. The magnetic field causes the cations in the liquid phase to be subjected to an upward Lorentz force as they flow toward the cathode, while the negatively charged discrete soil particles in the drainage channels formed by the voids in the soil are subjected to a downward Lorentz force as they move toward the anode. By adjusting one or more of the electric field strength, electric field direction, magnetic field strength, magnetic field direction, and interval time, a variable magnetic field combined with electroosmosis can be used to reinforce deep soft soil foundations.

[0010] Furthermore, before the variable magnetic field combined with electroosmosis treatment, magnetic treatment is also included: energizing the electromagnetic poles to generate a magnetic field parallel to the horizontal plane of the site, thus magnetically treating the site, adjusting the spin state of hydrogen and oxygen atoms in the liquid phase, improving chemical reaction kinetics, increasing ion mobility, and improving the drainage performance of the site.

[0011] Furthermore, electromagnetic electrodes and drainage electrodes are laid out in the site, with the drainage electrodes arranged at fixed intervals and an electromagnetic electrode placed between every four drainage electrodes.

[0012] Furthermore, a soil-breaking cone is also provided at the bottom of the electromagnetic pole.

[0013] Furthermore, the form in which multiple expansion rods are vertically fixed on the outer periphery of the inner tube is as follows: four expansion rods with different orientations and perpendicular to each other are set at fixed intervals along the axis of the inner tube.

[0014] Furthermore, the top of the inner tube is configured with a spiral bayonet, and the electromagnetic pole also includes a rotating tool with a thread that matches the spiral bayonet. The direction of the electromagnetic pole extension rod is adjusted by rotating the tool, thereby adjusting the direction of the magnetic field.

[0015] Furthermore, the direction of the magnetic field can be adjusted by changing the direction of the current flowing through the extension rod of the electromagnetic pole, and the strength of the magnetic field can be adjusted by changing the voltage and the magnitude of the current.

[0016] A device for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis, for implementing the above method, the device includes at least: an electromagnetic pole, a drainage electrode, and a power supply for power supply.

[0017] Furthermore, it also includes an electronic control system for controlling the direction and magnitude of current supplied by the power source to each extension rod and each drainage electrode in each electromagnetic pole.

[0018] Furthermore, the voltage signal output by the power supply is a sine wave, square wave, or pulse.

[0019] To optimize the above technical solution, the following measures were also taken:

[0020] On-site, surcharge preloading or vacuum preloading is carried out jointly. During surcharge preloading, a sand cushion layer is placed on the silt, and during vacuum preloading, a vacuum sealing film is placed on the silt and a vacuum is drawn.

[0021] The advantages of this invention are:

[0022] (1) Increase current density to enhance drainage efficiency

[0023] A variable magnetic field is applied perpendicularly to the direction of electroosmotic flow. By applying varying voltage signals, such as sine waves, square waves, or pulses, to the electromagnetic poles, a time-varying magnetic field is generated, whose strength and direction change over time. According to the principle of electromagnetic induction, the introduction of this time-varying magnetic field can excite ions in the liquid phase of the soil to generate induced currents, thereby enabling the migration and transformation of ions in the liquid phase, enhancing electroosmotic flow, and increasing current density.

[0024] (2) Multidimensional drainage expands drainage paths, improves drainage performance of deep soil, and coordinates settlement rates.

[0025] Under the influence of magnetoelectric coupling, the two-dimensional electric field composed of drainage electrodes arranged in both longitudinal and transverse directions within the site can uniformly drain water in both directions and fully utilize the advantage of electromagnetic electrodes generating magnetic fields in multiple directions, enabling multi-directional consolidation and drainage of the site. As cations in the liquid phase move horizontally towards the cathode, they experience an upward Lorentz force, carrying polar water molecules upwards with them. The drainage channel changes from a horizontal and downward channel caused by the coupling of the gravitational and electric fields to a horizontal and upward channel dominated by magnetoelectricity, significantly improving the drainage performance of deep soil. Simultaneously, the discrete negatively charged soil particles in the drainage channels experience a downward Lorentz force as they move towards the anode, causing them to move downwards and consolidate, greatly improving the internal pore channels of the soil and promoting overall soil settlement. By controlling the output voltage of the power supply connected to the specially arranged drainage electrodes and magnetic electrodes through an electronic control system, the directions of the magnetic and electric fields are reversed, causing cations in the electroosmotic flow to generate a reverse Lorentz force, coordinating the water content of the cathode and anode regions, and ensuring uniform soil settlement.

[0026] (3) Exhaust gas and improve energy efficiency

[0027] Magnetohydrodynamic (MHD) and micro-magnetohydrodynamic (MHD) effects are macroscopic and microscopic convections caused by the Lorentz force generated by the interaction of a magnetic field and local current density. When the drainage electrode and the magnetic electrode work simultaneously, their magnetoelectric coupling will generate MHD and MHD effects. Under the action of a variable magnetic field, this effect will be enhanced, reducing the adhesion of gas in the soil and causing it to move upward and be discharged from the soil. This significantly reduces the proportion of gas phase in the soil, ensuring good contact between the electrode and the soil and unobstructed drainage channels within the soil. In the electrocatalytic chemical reaction of water electrolysis, it can reduce ohmic polarization, activation polarization, and concentration polarization, thereby significantly reducing interfacial resistance, enhancing electroosmotic flow, and improving energy utilization.

[0028] (4) Purify the environment

[0029] In addition to reinforcing the foundation soil and improving its shear strength, magnetic treatment of deep, soft soil foundations through electro-osmotic drainage can generate eddy currents and induced currents in the soil through variable magnetic fields. This induces movement and friction in soil particles, accelerating the decomposition and volatilization of harmful organic substances, making them easier to degrade and remove, thereby purifying the soil and water. Furthermore, combined magnetic and electrical remediation, as a novel remediation technology, can also complex and aggregate heavy metals to achieve the goal of remediating heavy metal-contaminated soil.

[0030] (5) Better reduction of liquid phase surface tension and resistivity

[0031] Magnetic treatment using a variable magnetic field can better reduce the surface tension of the liquid phase, change the bonding and aggregation state between molecules, and make the molecules in the solution more ordered. Water containing ions has a certain conductivity. When an external variable magnetic field is applied, the Lorentz force does work on the particles in the water, increasing the internal energy and driving the spin state of oxygen in the water within the soil. This causes more violent collisions between particles in the liquid water, providing more energy to overcome the potential barrier and break the hydroxyl bonds, reducing the activation energy of water electrolysis, increasing the concentration of hydroxide ions in the water, greatly reducing resistivity, and enhancing ion mobility.

[0032] (7) Precisely adjust the relevant parameters of the magnetic field

[0033] Compared to existing magnetic poles, the electromagnetic pole of this invention overcomes the limitation of existing devices that cannot arbitrarily adjust magnetic field parameters. By adjusting the external voltage of the electromagnetic pole, precise control of the magnetic field parameters is achieved. Furthermore, a voltage signal editing function can be added, allowing the voltage to be set as a function of time, such as a sine function or a square wave function. By adjusting the frequency and amplitude of the function, the period and intensity of the magnetic field can be controlled. Simultaneously, the direction of the magnetic field can be reversed by controlling the polarity of the voltage. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the electric field distribution when the drainage electrode of the present invention is in operation;

[0035] Figure 2 This is a schematic diagram of the magnetic processing operation of the present invention;

[0036] Figure 3 This is a schematic diagram of the electromagnetic field distribution for the variable magnetic field combined with electroosmosis reinforcement of deep soft soil foundations according to the present invention;

[0037] Figure 4 This is a schematic diagram of the electromagnetic field distribution of the variable magnetic field combined with the electroosmotic drainage reversal electrode and the magnetic pole selective energization of the present invention.

[0038] Figure 5 This is a schematic diagram of the electromagnetic field distribution after the variable magnetic field is combined with the electroosmotic drainage reverse magnetic pole and electrode of the present invention;

[0039] Figure 6 This is a schematic diagram of the electromagnetic field distribution for one-dimensional drainage using a combined indoor variable magnetic field and electroosmotic drainage according to the present invention.

[0040] Figure 7 This is a side view of the electromagnetic poles of the present invention;

[0041] Figure 8 This is a 1-1 cross-sectional view of the electromagnetic pole of the present invention;

[0042] Figure 9 This is a full sectional view of the electromagnetic poles of the present invention;

[0043] In the diagram, 1 is the electromagnetic pole, 2 is the drainage electrode, 3 is the electric field line, 4 is the magnetic field line, 5 is the outer protective cover, 6 is the protective tube, 7 is the inner tube, 8 is the extension rod, 9 is the spiral bayonet protective cover, 10 is the fixed bayonet, 11 is the soil-breaking cone, and 12 is the rotating tool; 81 is the internal conductor coil, 82 is the built-in iron rod, 83 is the outer tube of the extension rod, 61 is the positive and negative conductor ports on the protective tube, and 71 is the positive and negative conductor ports on the inner tube. Detailed Implementation

[0044] This invention provides a method for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis. The method involves arranging electromagnetic electrodes 1 and drainage electrodes 2 within the site, and controlling the output voltage of the external power supply to the drainage electrodes 2 and electromagnetic electrodes 1 to flexibly adjust parameters such as electric field direction, electric field strength, magnetic field strength, magnetic field direction, and intermittent time. This ensures the electric and magnetic fields are perpendicular in real time, thereby guiding and enhancing electroosmotic flow, improving drainage channels, coordinating settlement in different areas of the site, improving the drainage performance of deep soil, significantly reducing drainage time, and increasing consolidation efficiency. The magnetic field is a variable, vertical magnetic field formed by several electromagnetic electrodes 1, parallel to the site's horizontal plane and perpendicular to the electric field, and can be controlled by the output voltage of the external power supply. The electroosmotic flow is caused by the electric field generated by the drainage electrodes 2, and the electric field lines 3 of the drainage electrodes 2 during operation are as follows: Figure 1As shown. Compared with ordinary magnetic treatment, the variable magnetic field combined with electroosmosis treatment technology applies a variable magnetic field in the direction perpendicular to the electroosmotic flow by arranging the electromagnetic electrode 1 and the drainage electrode 2. This better reduces the surface tension of the liquid, better reduces the resistivity of the solution, better enhances the ion mobility, changes the spin state of hydrogen and oxygen atoms in water molecules, lowers the activation energy of the electrolysis reaction, facilitates the electrolysis chemical reaction, and enhances electroosmotic drainage. The principle of improving drainage channels and guiding electroosmotic flow to accelerate drainage refers to the fact that, under the combined action of electromagnetic electrode 1 and drainage electrode 2, cations in the soil liquid phase carry polar water molecules towards the cathode. Under the action of a vertical magnetic field, the cations in the liquid phase are subjected to an upward Lorentz force as they flow towards the cathode, thus guiding the cations to carry water molecules horizontally and upward for drainage. This transforms the original horizontal and downward drainage channel composed of soil voids, which was formed by the coupling of gravity and electric fields, into a horizontal and upward channel dominated by magnetoelectricity. Simultaneously, the negatively charged discrete soil particles in the drainage channel composed of soil voids are subjected to a downward Lorentz force as they move towards the anode, thereby promoting overall settlement and consolidation. The principle of enhancing electroosmotic flow is to apply a vertical variable magnetic field in the direction perpendicular to the electroosmotic flow. By applying a changing voltage signal to electromagnetic electrode 1, a time-varying magnetic field is generated, whose strength and direction change over time. According to the principle of electromagnetic induction, the introduction of the time-varying magnetic field can excite various ions in the soil liquid phase to generate induced currents, enhance electroosmotic flow, increase the current density of water electrolysis, and thus improve electroosmotic efficiency. In addition, time-varying magnetic fields can also affect the microstructure and chemical reactions within the soil, promoting the dissociation of water molecules and the breaking of hydrogen bonds, thereby improving chemical reaction kinetics and reducing the activation energy of water electrolysis.

[0045] Specifically, the present invention provides a method for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis, which mainly includes:

[0046] First, the electromagnetic electrode 1 and drainage electrode 2 are arranged on the site. The number and position of the electromagnetic electrode 1 and drainage electrode 2 can be set according to requirements, ensuring that the drainage electrode 2 can generate an electric field parallel to the horizontal plane of the site, and the electromagnetic electrode can generate a magnetic field parallel to the horizontal plane of the site. A quincunx arrangement of electrodes is generally preferred in conventional electroosmosis methods. However, considering the need for an external vertical variable magnetic field and the mechanism of its action, different electrode planar arrangements are used, such as rectangular, parallelogram, and strip arrangements. As a preferred option, when conducting one-dimensional drainage consolidation tests on silt and soft soil indoors, the electromagnetic electrodes can be arranged in a strip shape to form a stable vertical magnetic field throughout the site. Figure 6 As shown. Preferably, in the actual two-dimensional drainage, the drainage electrodes 2 are arranged in a rectangular plane at fixed intervals, with an electromagnetic pole 1 set at the center of every four drainage electrodes 2, as shown. Figure 2As shown, this ensures that the electric fields formed by the two drainage electrodes 2 are matched with magnetic fields, allowing for faster and more uniform electroosmosis.

[0047] Figure 7-9 It is an electromagnetic pole structure, such as Figure 7-9 As shown, the electromagnetic pole includes an outer protective cover 5, a protective tube 6, an inner tube 7, and an extension rod 8. The extension rod 8 consists of an inner iron rod 82 and an internal conductor coil 81 wound in a fixed direction around the inner iron rod 82. The outer protective cover 5 is a circular material that meets the design requirements, protecting the upper part of the device from possible damage or deformation during installation. The protective tube 6 is a circular hollow steel tube that meets the design requirements and is located on the outermost periphery of the device to ensure the normal operation of the internal device. The inner tube 7 is a circular hollow steel tube that meets the design requirements, and its wall has multiple holes for vertically fixing the extension rod 8, so that the extension rod 8 can generate a magnetic field parallel to the horizontal plane of the site. The number and position of the expansion rods 8 can be arranged according to requirements. As a preferred embodiment, four spiral holes with different orientations and perpendicular to each other can be set every 0.50m along the axis of the inner tube 7 for connecting the expansion rods 8. Among the four expansion rods 8, the internal coils 81 of the parallel expansion rods 8 have the same winding direction, while the internal coils 81 of the vertical expansion rods 8 have the opposite winding direction, ensuring that the effect and depth of the magnetic field meet the design requirements and improving the drainage performance of the deep soil. The end of the expansion rod 8 adopts a spiral bayonet design that matches the inner tube 7, which is convenient for disassembly and replacement. Preferably, the top of the inner tube 7 is set with a spiral bayonet. The electromagnetic pole 1 also includes a rotating tool 12, which is provided with a thread that matches the spiral bayonet. By rotating the inner tube 7 through the rotating tool 12, the orientation of the expansion rod 8, i.e., the direction of the magnetic field, can be adjusted. The upper spiral bayonet is equipped with a corresponding spiral bayonet protective cover 9 to prevent sand and gravel in the site from entering the inner tube 7 and damaging the circuit, thereby ensuring the normal operation of the device; the bottom of the electromagnetic pole is also equipped with a soil-breaking cone 11, and the fixing bayonet 10 is fixedly connected to the top of the soil-breaking cone 11. The fixing bayonet 10 is a circular bayonet that matches the inner tube 7 and is used to prevent the inner tube from swaying and shifting left and right; the soil-breaking cone 11 is a rigid body that meets the design requirements and is easy to arrange and install.

[0048] Secondly, after the electrodes are arranged, the external power supply of electromagnetic pole 1 can generally be turned on first to form a stable vertical magnetic field. The magnetic field lines 4 generated by electromagnetic pole 1 are as follows: Figure 2 As shown, a novel technique called variable magnetic field is used to magnetically treat the site, adjusting the spin state of hydrogen and oxygen atoms in the liquid phase, improving chemical reaction kinetics, increasing ion mobility, and enhancing the site's drainage performance.

[0049] After a suitable period of magnetic treatment, turn on the external power supply for drain electrode 2. At this time, magnetic electrode 1 and drain electrode 2 work together, such as... Figure 3A stable electromagnetic field is formed in the site, with the magnetic field perpendicular to the corresponding electric field. Cations carrying polar water molecules in the liquid phase move horizontally upward under the drive of electric field force and Lorentz force. The drainage channel changes from a horizontal and downward channel caused by the coupling of the gravitational field and electric field to a horizontal and upward channel dominated by magnetoelectric force, allowing the liquid phase in the deep soil to be discharged upward to the soil surface. Negatively charged soil particles dispersed in the drainage channel composed of soil pores move horizontally downward and consolidate under the action of electric field force and Lorentz force, ensuring the drainage channel and promoting the overall soil drainage and consolidation. The gas phase in the soil generates magnetohydrodynamic and micro-magnetic-hydrodynamic effects (MHD effect) due to the magnetoelectric coupling effect, and is subjected to an upward Lorentz force, discharging upward to the soil, thereby improving the drainage channel in the soil and promoting consolidation efficiency.

[0050] Furthermore, when electromagnetic electrode 1 and drainage electrode 2 work together, the resulting electromagnetic field state causes water molecules in the site to accumulate towards the cathode and be discharged upwards into the soil. In addition, due to various factors in actual engineering, such as the time difference of energization and the heterogeneous properties of the soil, the horizontal and vertical directions (e.g.) Figure 3 The treatment effect in the x and y directions is uneven. Therefore, the directions of the electric and magnetic fields are adjusted to coordinate the horizontal and vertical directions of the site and the water content of the cathode and anode areas within the site, ensuring uniform settlement. For example, the drainage electrode 2 can be reversed, causing the electric field direction to change. At this time, the magnetic field direction of the extension rod 8 in the electromagnetic electrode 1 should also be reversed to ensure that the magnetic field causes the cations in the liquid phase to experience an upward Lorentz force when flowing towards the cathode, and the negatively charged discrete soil particles in the drainage channels formed by the voids in the soil to experience a downward Lorentz force when moving towards the anode. Alternatively, a magnetic field can be set in one direction, i.e., selectively energizing the extension rod 8 of the magnetic electrode, controlling the external voltage of the electromagnetic electrode 1 and the drainage electrode 2. This allows the magnetic field and electric field directions to be adjusted according to the horizontal and vertical drainage conditions of the site and the water content of the cathode and anode areas in the actual project. Figure 4 As shown, after reversing the magnetic poles and electrodes, selectively energizing the electromagnetic poles results in a Lorentz force generated by the electromagnetic coupling effect, which can cause the field to move in a single direction, i.e., longitudinally (e.g., ...). Figure 4 (In the x-direction) the liquid phase is drained upwards to coordinate settlement in the horizontal and vertical directions within the site. For example... Figure 5 As shown, by simultaneously reversing the electromagnetic pole 1 and the drainage electrode 2, water molecules in the original cathode region of the site move towards the new cathode, and then redistribute and drain upwards under the action of magnetoelectric coupling, coordinating the water content of the cathode region and the anode region to ensure uniform settling. Specifically, the electroosmosis method for strengthening deep soft soil with magnetic treatment of the present invention is a method of uniform upward drainage based on electrode reversal and magnetic pole reversal.

[0051] Furthermore, the magnetic field is a stable magnetic field composed of several rows of electromagnetic poles 1 spaced at fixed distances (e.g., 1m) according to the actual size of the work site. The electromagnetic poles 1 can adjust parameters such as magnetic field strength, direction, and duration of action through an electronic control system.

[0052] Furthermore, the output voltage of the external power supply in the electromagnetic pole can be edited according to actual needs and set as a time-varying voltage. The voltage signal can be in the form of sine wave, square wave, pulse, etc., thereby generating a time-varying magnetic field, which causes the movement of liquid phase cations in the soil to generate an accompanying induced current, enhance electro-osmosis, increase drainage rate, and improve consolidation efficiency.

[0053] Furthermore, the outer protective cover 5 and the protective tube 6 are connected by a spiral bayonet, which facilitates disassembly, assembly, and repair.

[0054] Furthermore, the outer protective cover 5, the protective pipe 6, and the soil-breaking cone 11 constitute the outermost protective system of the device.

[0055] Furthermore, the extension rods 8 inside the electromagnetic poles are connected in parallel circuits and switched on by a switch to ensure the stability of the device's operation.

[0056] Furthermore, the inner tube 7 integrates the wires of each layer of expansion rods 8, and the integrated wires are led out from the positive and negative wire ports 71 on the inner tube and connected to the positive and negative wire ports 61 on the protective tube. Thus, current supplies power to the internal device through the circuit channel formed by the positive and negative wire ports 61 on the external protective tube and the positive and negative wire ports 71 on the inner tube. An external power supply connects to the positive and negative wire ports 71 on the inner tube 7 via the wire ports 61 on the protective tube 6, thus supplying power to the device.

[0057] Furthermore, the extension rod 8 is a standard part, making it easy to replace.

[0058] Furthermore, the extension rod 8 also includes an extension rod outer sleeve 83 disposed outside the built-in iron rod 82, for protecting the built-in iron rod 82 and the internal conductor coil 81.

[0059] Furthermore, the end of the extension rod 8 has two wire interfaces, which are connected to the wires in the inner tube 7 through the spiral holes on the inner tube 7 to ensure the safety of the circuit and the normal operation of the device.

[0060] Furthermore, the extension rod 8 generates magnetism using the principle of electromagnetism, creating a variable vertical magnetic field in the soil.

[0061] A specific embodiment of the method for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis provided by the present invention includes the following steps:

[0062] (1) Site leveling: Level the soft soil site to be treated, and at the same time excavate drainage ditches on the site surface and around the site to facilitate the timely drainage of water from the site.

[0063] (2) Deployment of electromagnetic electrode 1 and drainage electrode 2: Select drainage distribution points and magnetic treatment distribution points evenly in the site according to the design requirements, and then drive drainage electrode 2 and electromagnetic electrode 1 to the design depth at each distribution point. Specifically, drive the soil-breaking cone 11 of electromagnetic electrode 1 downward into the soil at a certain position so that the positive and negative conductor ports 61 on the protective pipe are exposed on the ground surface, which is convenient for connecting external power supply.

[0064] (3) Adjust the orientation of electromagnetic pole 1: Use a tool to remove the spiral bayonet protective cover 9 on the upper part of the inner tube 7, and then use the matching rotating tool 12 to rotate the inner tube 7. At the same time, observe the orientation of the expansion rod 8, that is, adjust the magnetic field. After rotating the expansion rod 8 to the appropriate position, remove the matching rotating tool 12 and put the spiral bayonet protective cover 9 back on to prevent dust from entering the internal device and ensure the stability of the internal circuit of the inner tube 7.

[0065] (4) Electromagnetic pole 1 is energized: An external power supply is connected to the positive and negative wire ports 61 on the protective pipe exposed on the ground through a wire, thereby supplying power to the coil 81 inside the extension rod to form a stable circuit. When the switch of the external power supply of the electromagnetic pole is turned on, opposite DC current is supplied to the adjacent electromagnetic pole 1 in the field. According to the principle of electromagnetism, the coil 81 inside the extension rod will generate magnetism after being energized, thereby generating a variable magnetic field that is always perpendicular to the direction of the electric field.

[0066] (5) Magnetic treatment: Only turn on the switch of the external power supply of electromagnetic pole 1, and use the various effects of the variable magnetic field to perform magnetic treatment on the site, reduce the surface tension and viscosity of the liquid phase, greatly increase the ion mobility, and improve the chemical reaction kinetics.

[0067] (6) Electromagnetic combined drainage: Turn on the external power supply of drainage electrode 2, and apply opposite DC current to adjacent drainage electrodes 2 in the site. At the same time, selectively energize the extension rod 8 of the magnetic electrode so that the electric field and magnetic field are perpendicular to each other. The magnetic field and electric field combine to drain water, inducing cations in the liquid phase to carry polar water molecules upward. The drainage channel changes from a horizontal and downward channel coupled with the gravitational field and electric field to a horizontal and upward channel dominated by magnetoelectricity. It induces the discrete negatively charged soil particles in the drainage channel to move downward and consolidate, improves the drainage channel, and promotes the overall soil settlement. It reduces the adhesion of gas in the soil, improves the mass transfer on the electrode surface and the unobstructed drainage channel in the soil.

[0068] (7) Adjusting the variable magnetic field: During construction, the output voltage of the external power supply of the electromagnetic pole 1 can be flexibly adjusted through the electronic control system according to the specific conditions of the actual project. A changing voltage signal can be applied to the electromagnetic pole 1, which can be in the form of sine wave, square wave, pulse, etc., to change the direction and magnitude of the current in the internal coil 81 of the extension rod, thereby adjusting the magnitude and direction of the magnetic field, generating a time-varying magnetic field whose magnetic field strength and direction change over time, coordinating the water content of the cathode and anode areas in the site, and ensuring uniform drainage in both the horizontal and vertical directions of the site, improving drainage efficiency, and ensuring uniform soil settlement. It also stimulates various ions in the liquid phase of the soil to generate induced current, enhances electroosmotic flow, increases the current density of water electrolysis, improves the microstructure and chemical reaction activation energy in the soil, promotes the dissociation process of water molecules and the breaking process of hydrogen bonds, and improves electroosmotic efficiency.

[0069] (8) Adjusting the electric field: During the construction process, the output voltage of the external power supply of the drainage electrode 2 is adjusted or reversed through the electronic control system according to the specific conditions of the actual project, so as to promote the redistribution of the liquid phase in the site, so that the liquid phase in the horizontal and vertical directions of the site is drained upward evenly, thereby improving the consolidation efficiency.

[0070] (9) After the construction is completed, pull out electromagnetic electrode 1 and water electrode 2 and reuse them.

[0071] Common methods for reducing energy consumption and improving the effect of electroosmotic reinforcement, such as electrode reversal, intermittent energization, and stepwise pressurization, can also be applied in the novel magnetic treatment-enhanced electroosmotic drainage method. Preferably, during the electroosmosis process, methods such as electrode reversal, electromagnetic pole reversal, intermittent electrode energization, intermittent electromagnetic pole energization, and adjustment of magnetic field strength are implemented according to the actual drainage situation. The reversal time and the magnitude of the magnetic pole strength depend on the soil dehydration condition.

[0072] This invention can also be implemented in conjunction with other methods, such as surcharge preloading or vacuum preloading. In surcharge preloading, a sand cushion layer is placed on the silt, and preloading soil is applied. When used in conjunction with vacuum preloading, the soil maintains unobstructed upward drainage channels under the influence of a magnetic field, thereby allowing the liquid phase in deeper soil layers to move upwards, increasing the effective drainage depth of vacuum preloading, significantly reducing the vacuum preloading attenuation coefficient, improving the transmission performance of vacuum pressure, and accelerating silt dewatering.

[0073] This invention provides a method for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis. This method combines a variable magnetic field to perform novel magnetic treatment on the liquid phase within the site with its effect on electroosmotic flow within the soil, achieving a good dewatering effect on deep silty soft soil. The successful implementation of the magnetic treatment electroosmosis method relies on the proper adjustment of the external voltage between the drainage electrode and the electromagnetic electrode via an electronic control system, thereby adjusting various relevant parameters of the magnetic and electric fields.

[0074] Corresponding to the aforementioned embodiment of a method for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis, the present invention also provides an embodiment of an apparatus for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis.

[0075] The present invention provides an apparatus for reinforcing deep soft soil foundations with a variable magnetic field combined with electroosmosis, which is used to implement the aforementioned method for reinforcing deep soft soil foundations with a variable magnetic field combined with electroosmosis. The apparatus includes at least: an electromagnetic pole, a drainage electrode, and a power supply for power supply.

[0076] Furthermore, it also includes an electronic control system for controlling the direction and magnitude of power supply to each extension rod and each drainage electrode in each electromagnetic pole.

[0077] The above description is merely a specific embodiment of the present invention. It should be noted that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis, characterized in that, include: Electromagnetic poles and drainage electrodes are laid out in the site; the electromagnetic pole includes a protective tube, an inner tube fixed inside the protective tube and an extension rod, and an outer protective cover set on the top of the protective tube. The extension rod consists of an inner iron rod and an internal conductor coil wound in a fixed direction around the inner iron rod; multiple extension rods are vertically fixed on the outer periphery of the inner tube. Variable magnetic field combined with electroosmosis treatment: When an electromagnetic electrode and a drainage electrode are energized, the drainage electrode generates an electric field, and the electromagnetic electrode generates a magnetic field that is parallel to the horizontal plane of the site and perpendicular to the electric field. The magnetic field causes the cations in the liquid phase to be subjected to an upward Lorentz force as they flow toward the cathode, while the negatively charged discrete soil particles in the drainage channels formed by the voids in the soil are subjected to a downward Lorentz force as they move toward the anode. By adjusting one or more of the electric field strength, electric field direction, magnetic field strength, magnetic field direction, and interval time, a variable magnetic field combined with electroosmosis can be used to reinforce deep soft soil foundations.

2. The method according to claim 1, characterized in that, Before the variable magnetic field combined with electroosmosis treatment, magnetic treatment is also included: energizing the electromagnetic poles to generate a magnetic field parallel to the horizontal plane of the site, thus magnetically treating the site, reducing the viscosity and surface tension of the liquid, adjusting the spin state of hydrogen and oxygen atoms in the water molecules in the liquid phase, improving the chemical reaction kinetics, increasing the migration rate of ions such as sodium, potassium, and hydroxide, and improving the drainage performance of the site.

3. The method according to claim 1, characterized in that, Electromagnetic electrodes and drainage electrodes are laid out in the field. The drainage electrodes are arranged at fixed intervals, and an electromagnetic electrode is set in the middle of every four drainage electrodes.

4. The method according to claim 1, characterized in that, The bottom of the electromagnetic pole is also equipped with a soil-breaking cone.

5. The method according to claim 1, characterized in that, The form in which multiple expansion rods are vertically fixed on the outer periphery of the inner tube is as follows: four expansion rods with different orientations and perpendicular to each other are set at fixed intervals along the axis of the inner tube.

6. The method according to claim 1, characterized in that, The top of the inner tube is set with a spiral bayonet. The electromagnetic pole also includes a rotating tool with a thread that matches the spiral bayonet. The direction of the electromagnetic pole extension rod is adjusted by rotating the tool, thereby adjusting the direction of the magnetic field.

7. The method according to claim 1, characterized in that, The direction of the magnetic field can be adjusted by changing the direction of the current flowing through the extension rod of the electromagnetic pole, and the strength of the magnetic field can be adjusted by changing the voltage and thus the magnitude of the current.

8. A device for reinforcing deep soft soil foundations using a variable magnetic field combined with electroosmosis, characterized in that, For implementing the method according to any one of claims 1-7, the apparatus includes at least: an electromagnetic pole, a drainage electrode, and a power supply for powering the device.

9. The apparatus according to claim 8, characterized in that, It also includes an electronic control system for controlling the direction and magnitude of current supplied to each extension rod and each drainage electrode in each electromagnetic pole.

10. The apparatus according to claim 9, characterized in that, The voltage signal output by the power supply is a sine wave, square wave, or pulse.

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