CN111576389B - Bottom-to-top graded electroosmosis drainage deep and soft foundation treatment method and device based on' electrode movement - Google Patents

Abstract

The invention discloses a bottom-up graded electro-osmotic drainage deep and thick soft foundation treatment method and device based on 'electrode movement', wherein the method comprises the steps of bottom-up graded electro-osmotic drainage: the method comprises the steps of air pressure splitting and electroosmosis construction; the air pressure splitting is to inject air and a modifier into the graded conductive air duct to cause the soil around the electrode to generate cracks; the hierarchical pipe comprises a main pipe, an inner pipe and a sleeve which are coaxially sleeved, the main pipe is composed of conductive pipes connected through non-conductive connectors, holes are formed in the surfaces of the main pipe and the inner pipe, the number of the holes in the inner pipe is less than that of the main pipe, and the holes in the inner pipe are communicated with the holes in the main pipe through the hole channels. The sleeve pipe is tightly attached to the inner wall of the inner pipe, and one section of the conductive pipe is a first level. The invention has the advantages of manufacturing the construction effect of the 'movable electrode' in the soil body, constructing step by step, flexibly controlling the splitting and electroosmosis process parameters of each step, improving the permeability coefficient, accelerating the consolidation speed of the soil body, improving the treatment uniformity and solving the problems of poor electroosmosis effect and high energy consumption of the deep soil body in the deep and thick soft clay electroosmosis method.

Description

Bottom-to-top graded electroosmosis drainage deep and soft foundation treatment method and device based on' electrode movement

Technical Field

The invention relates to the technical field of geotechnical engineering, in particular to a bottom-up graded electro-osmotic drainage deep and soft foundation treatment method based on 'electrode movement'.

Background

The electroosmosis method applies direct current to electrodes inserted into soil to accelerate drainage consolidation of the soil and improve the strength, has drainage efficiency unrelated to the size of soil particles, is considered to be a method with development prospect for treating fine-grained soil with high water content and low permeability, and receives wide attention. Scholars at home and abroad continuously try to apply the soft soil to various soft soil projects, although the successful examples are not lacked, the soft soil projects are not widely popularized and applied, and the main reasons of the soft soil projects comprise three aspects: uneven treatment effect, poor deep soil treatment effect and large energy consumption.

The reason for the uneven treatment effect is that a large amount of cations are gathered near the cathode of the soil body at the later stage of electroosmosis and cannot be discharged out of the soil body, and meanwhile, the condition of 'soil body dry cracking' can occur at the anode.

When the electroosmosis method is used in deep and thick soft foundation treatment engineering, the treatment effect of the deep soil body is poor mainly reflected in two aspects: (1) the electric potential is gradually attenuated in the process of transferring to the deep part along the electrode plate, and for the deep and thick soft foundation, the current passing through the deep soil body is small, and the electroosmosis effect is poor; (2) the deep soil body has low porosity and poor conductivity.

The reason that the electroosmosis energy consumption is large is that the electric energy utilization rate is low when the electroosmosis energy consumption is electrified, the effective contact between the electrode and the soil body is poor, and the power supply continuously supplies power for a long time under the condition that the electroosmosis efficiency is low.

The invention provides a solution for the problems of uneven treatment effect, poor deep soil treatment effect and large energy consumption.

Disclosure of Invention

The invention aims to solve the defects of the background technology and provide a bottom-up graded electroosmotic drainage deep and soft foundation treatment method based on 'electrode movement'.

The technical scheme of the invention is as follows: a bottom-up classification electroosmosis drainage deep and soft foundation treatment method based on 'electrode movement' is characterized in that electroosmosis drainage is sequentially performed from bottom to top, wherein each stage of electroosmosis drainage comprises air pressure splitting and electroosmosis construction steps; the air pressure splitting process comprises the following steps: gas and a modifier with electric conductivity are injected into the hierarchical conductive gas-guide tube, the gas is sprayed from the holes to enable cracks to be generated in soil bodies around the electrodes, and the modifier is filled into the soil bodies along the cracks to enable the soil bodies around the cracks to be solidified and to be conductive. The hierarchical type conductive air duct is composed of a main tube, an inner tube and a sleeve which are coaxially sleeved, the main tube is composed of a plurality of sections of conductive tubes, the conductive tubes are connected through non-conductive connectors, through holes are formed in the surfaces of the main tube and the inner tube, the number of the holes in the inner tube is less than that of the main tube, and the holes in the inner tube are communicated with the holes in the main tube through hole channels. The sleeve pipe is tightly attached to the inner wall of the inner pipe, and each section of the conductive pipe is a first-level.

Further, the modifier comprises a curing agent and a flocculating agent with conductive properties. Flocculants such as Polyacrylamide (PAM), including Cationic Polyacrylamide (CPAM), Anionic Polyacrylamide (APAM), non-ionic polyacrylamide, and the like.

The curing agent may be a conventional ionic curing agent.

Furthermore, the inner pipe is provided with holes at intervals of 1m along the pipe axis direction, and each hole is provided with 4 holes at equal intervals along the circumferential direction of the pipe wall, and the hole diameter is 2-5 mm.

Further, the modifier is mixed with gas to form aerosol, and then the aerosol is introduced into the graded conductive gas-guide tube.

Further, in the electroosmosis process, processes such as intermittent electroosmosis, intermittent air pressure cleavage, and/or electrode inversion are performed.

The invention also provides an electroosmosis consolidation device based on the method, which comprises a box body, a graded conductive gas guide pipe arranged in the box body, an external power supply for providing a stable power supply for the graded conductive gas guide pipe, a water pumping device, a gas pressure source for providing gas and a modifier injection source for providing a modifier. The water pumping device, the air pressure source and the modifier injection source are all connected with the graded conductive gas-guide tube through pipelines.

Further, the device also comprises a preloading device or a vacuum preloading device.

The sludge dewatering or soft foundation treatment in site construction includes an air pressure splitting device and a relevant electroosmosis drainage consolidation device. The electroosmotic drainage consolidation device comprises: the grading type conductive gas guide tube, the external power supply and the electrified lead; the atmospheric pressure splitting device includes: a pneumatic source, a gas guide tube and a modifier injection source. The features of the above apparatus include: the air duct and the water discharge pipe are the same pipeline, and can be used for high-pressure gas transmission of air pressure splitting, can also be used for pumping water by a water pumping device, and has the functions of electric conduction, air guiding and water discharging. When the air pressure is split, a modifier with conductive performance is injected, so that the soil body around the split crack maintains stability for a certain time, and pore water can fill the crack, so that the crack can be used as a new 'electrode'. The sludge dewatering or deep soft foundation treatment comprises the following steps:

(1) leveling the field: the method comprises the steps of leveling a to-be-treated soft soil body field, and digging drainage ditches around the field to conveniently drain water of the field in time, wherein the field is optimally formed with a certain drainage gradient.

(2) A graded conductive air duct is arranged: and uniformly distributing and selecting drainage distribution points in the field according to design requirements, and then striking the graded conductive gas-guide tube to the designed depth at each distribution point.

(3) Arranging an electroosmosis device, connecting an external power supply and a water pumping device with the hierarchical conductive gas-guide tube, and arranging a lead line and a drainage and exhaust pipeline connected with the hierarchical conductive gas-guide tube; and then the air pressure source and the modifier injection source are connected with the graded conductive gas guide pipe through a drainage pipeline and a gas exhaust pipeline.

(4) Firstly, the casing pipe is extracted to expose the deepest inner pipe hole, an air pressure source and a modifier injection source are opened to carry out air pressure splitting to enable cracks to be generated in soil around the electrode, the cracks are filled with water and modifiers with electric conductivity, after the soil around the cracks is solidified, a power supply of a first-stage conductive pipe is connected, a water pumping device is started, and electroosmotic drainage of the soil around the first stage is carried out until the soil around the first stage is solidified.

(5) And (4) gradually exposing each stage of inner pipe hole of the extraction sleeve, and gradually performing electroosmotic drainage according to the method in the step 4 to finish the step-up electroosmotic drainage consolidation work.

(6) And finishing the construction.

In order to optimize the technical scheme, the adopted measures further comprise:

and (3) carrying out preloading or vacuum preloading jointly in the field, wherein a sand cushion layer is coated on the silt soil during preloading, and a vacuum sealing film is coated on the silt soil during vacuum preloading.

The air pressure source is an air compressor, and the splitting gas is aerosol formed by high-pressure air mixed with the modifier.

Preferably, the outer wall and the bottom of the graded conductive gas guide pipe are wrapped with a non-conductive geotextile filter layer. The hierarchical conductive gas-guide tube has high hardness and can keep stable structure and good sealing performance under large splitting pressure.

Preferably, the air pressure splitting causes the aerosol to generate cracks in the soil body in a rotary spraying mode. The air pressure splitting parameters such as the air guide hole spacing, the distribution shape, the air injection pressure, the air injection quantity, the air injection interval and the like are determined according to specific conditions.

The invention has the advantages that:

the electroosmosis method of 'moving electrode' comprehensively utilizes a crack channel formed by an air pressure splitting method, and injects a conductive modifier to change an originally fixed electrode from a 'fixed tree type' into a 'gradually growing tree type'. The space between the electrodes is changed from 'invariable' to 'gradually reduced', the drainage of the soil body is also changed from 'micro capillary channels' to 'criss-cross tributaries', and the drainage performance is greatly improved.

2. The treatment from bottom to top is beneficial to improving the depth of treating the soft foundation by the electroosmosis method, can effectively utilize the self-weight stress of the upper soil body, can treat deep sludge for a long time and saves energy consumption. The current situation of poor conductivity of the deep soil body is effectively solved by artificially extending the electrodes. The deep soft clay difficult to reinforce is subjected to targeted treatment, and the treatment effect is improved by optimizing air injection parameters such as air injection pressure, air injection quantity and air injection interval, and electroosmosis parameters such as voltage and electrifying time;

3. the pipe wall of the main pipe in the graded conductive gas-guide pipe is provided with dense small holes for guiding water. The non-conductive inner tube is used for gas injection splitting, so that holes are formed at intervals of 1m along the tube wall, a modifier is made into high-pressure atomized aerosol which is sprayed out from a small hole, a soil body generates directional cracks under the splitting action, the modifier is filled into the soil body along the continuously expanded cracks, the modifier is like a continuously growing dendritic small electrode, and the potential applied to the position of the electrode can smoothly move to the end part of the cracks, so that the distance between a cathode and an anode is greatly shortened, the contact between soil and the electrode is enhanced, the continuity of an electric field is ensured, and the drainage effect is greatly increased.

4. Based on the effect of a 'moving electrode', the gas injection pressure and the gas injection quantity are changed, a proper modifier is selected, the reinforcement range and the reinforcement effect are flexibly adjusted, and the problem of non-uniformity of soft soil treatment by an electroosmosis method is effectively solved. The 'moving electrode' electroosmosis method based on air pressure splitting provides an innovative idea for solving the problems of uneven treatment and large energy consumption which are puzzled for a long time by electroosmosis.

Drawings

FIG. 1 is a schematic view of a staged electro-conductive airway device of the present invention; in the figure, (A) is a side view, (B) is a section view A-A, (C) is a schematic view of a non-conductive inner tube and a non-conductive sleeve;

FIG. 2 is a schematic diagram of the electroosmotic drainage consolidation method and apparatus of the present invention, wherein (A) is a schematic diagram of a first stage treatment, (B) is a schematic diagram of a second stage treatment, and (C) is a schematic diagram of a final stage treatment;

in the figure, 1 is a box body, 2 is an external power supply, 3 is an air pressure source, 4 is a pipeline, 5 is an electrode hole, 6 is a soil body, 7 is a graded conductive gas guide tube anode, 8 is a graded conductive gas guide tube cathode, 9 is a modifier injection source, 10 is a water pumping device, 11 is a splitting crack, and 12 is a mixture of pore water and a modifier; 71 is a conductive tube, 72 is an inner tube, 73 is a sleeve, 74 is a joint, and 51 is an air guide hole;

Detailed Description

The invention provides a bottom-up graded electroosmosis drainage deep and thick soft foundation treatment method for 'electrode movement', which sequentially carries out electroosmosis drainage from bottom to top step by step, wherein each stage of electroosmosis drainage comprises the steps of air pressure splitting and electroosmosis construction; the air pressure splitting process comprises the following steps: gas and a modifier with conductivity are injected into the hierarchical conductive gas-guide tube, the gas is sprayed from the holes to enable cracks to be generated in soil around the electrode, the cracks are filled with water with good conductivity, and the modifier is filled into the soil along the cracks to enable the soil around the cracks to be solidified and to be conductive. The hierarchical type conductive air duct is composed of a main tube, an inner tube 72 and a sleeve 73 which are coaxially sleeved, the main tube is composed of a plurality of sections of conductive tubes 71, the conductive tubes 71 are connected through a non-conductive joint 74, through holes are formed in the surfaces of the main tube and the inner tube 72, the number of the holes in the inner tube 72 is less than that of the main tube, and the holes in the inner tube 72 are communicated with the holes in the main tube through hole channels. The sleeve 73 is tightly attached to the inner wall of the inner pipe 72, and each section of the conductive pipe 71 is a stage.

In the invention, the gas has the function of enabling the soil around the electrode to generate cracks and conveying the modifier into the cracks. The gas may be any gas that does not react with the modifier, such as air, nitrogen, oxygen, argon, and the like. In addition, in order to uniformly convey the modifier into the cracks, the modifier can be mixed with air to form aerosol and then the aerosol is introduced into the graded conductive gas-guide tube.

The modifier comprises a curing agent and a flocculating agent with conductive performance, and the flocculating agent and the curing agent are used for flocculating and solidifying soil around the cracks, maintaining stability for a certain time and enabling the cracks to become stable drainage channels. The conductivity and permeability of the modifier are the key points for the success of the 'moving electrode' electroosmosis method, the category, concentration and proportion of the modifier (including flocculating agent and curing agent) are improved according to the organic matter content, chemical components and physical characteristics of the dredged sludge/sludge, and the proper type of the modifier is determined by comparison and selection. Preferably, in general, the flocculating agent can be selected from Polyacrylamide (PAM) solution, including Cationic Polyacrylamide (CPAM), Anionic Polyacrylamide (APAM), nonionic polyacrylamide solution, etc., and the curing agent can be selected from commonly used soil curing agents, such as calcium chloride solution, ionic curing agent, etc., preferably liquid ionic soil curing agent.

Specifically, electroosmotic drainage of a deep soil body is firstly carried out: the extraction sleeve 73 is arranged above the first conductive pipe section 71, so that the air guide hole 51 on the inner pipe 72 is opened and the air guide hole 51 above is closed. Gas and a modifier are injected into the inner tube 72 for gas injection splitting, as shown in fig. 2, the gas and the modifier are injected into the soil body through the pore channels, so that cracks are generated in the soil body around the electrode, water is filled into the cracks, and the soil body around the cracks is mixed with the modifier to form a modifier treatment layer. The water in the crevices contains inorganic salts that are capable of introducing an electrical potential into the modifier treatment layer. After the gas injection is stopped, the modifier treatment layer is kept stable under the action of a flocculating agent and a curing agent contained in the modifier, so that a stable drainage channel can be formed in the crack. And the flocculant (PAM) dissociates negatively charged functional groups and H in the aqueous solution⁺The modifier treatment layer has good conductivity, and the good conductivity of the modifier treatment layer ensures that the potential can be transmitted to the soil body, so that the cleavage fracture can be ensured to play a role in conducting. The conductivity of the pore water and the modifier is far higher than that of the sludge, particularly when the effective potential transmission is severely limited by the interface resistance between the electrode and the sludge, and the water in the crack and the modifier treatment layer are used as good conductive layers and are obviously superior to the sludge, so that the contact performance with the electrode is improved, the interface resistance can be greatly reduced, and the electric energy utilization rate is improved. The slit is made to act as a new "electrode" as the electrode potential is transferred to the slit end with greater efficiency. The originally fixed electrode is changed from a fixed tree type into a gradually growing branch type; the distance between the electrodes is changed from 'constant' to 'gradually reduced', and the distance between the electrodes is extremely largeThe contact area of the electrode and the sludge is expanded, and higher effective potential can be applied to the soil body outside the tail end of the crack, so that the effect of electrode movement is achieved. Meanwhile, the drainage of the soil body is changed from a microcapillary channel into a criss-cross branch, and the drainage performance is greatly improved. Along with the gradual progress of electroosmosis dehydration, the water content of the soil body is reduced, especially the resistivity of the anode region is increased rapidly, the splitting crack is also shrunk gradually, and at the moment, the modifier is fully mixed with the soil body around the crack, so that the soil body can still be ensured to have good conductivity in the later stage of electroosmosis. The gas injection splitting and intermittent electrification are combined, so that a new conductive path can be guaranteed to be opened up in the soil body at any time, the conductivity of a splitting fracture area can be correspondingly improved by synchronously injecting the modifier, the generation of joule heat is reduced, and the energy utilization rate is improved.

For the deep and thick soft foundation, the deep part which is difficult to treat by the traditional electroosmosis method can be treated firstly, and the deep treatment effect is improved. After electro-osmotic drainage of the deep soil is completed, electro-osmotic drainage is carried out step by step on the upper extraction sleeve 3, and graded electro-osmotic drainage from bottom to top is completed.

Preferably, the inner wall surfaces of the sleeve 73 and the inner tube 72 are coated with a lubricant to facilitate extraction.

The length of the conductive pipe 71 is usually 0.5 to 1 meter, and it can be set according to the deep soft foundation soil.

In addition, it should be noted that there is no absolute precedence relationship between the electroosmosis construction and the air pressure splitting step, and the electroosmosis construction may be performed after the air pressure splitting, or may be performed after the air pressure splitting.

The invention also provides an electroosmosis consolidation device based on the method, which comprises a box body 1, a hierarchical conductive air duct arranged in the box body, an external power supply 2 for providing a stable power supply for the hierarchical conductive air duct, a water pumping device 10, a gas pressure source 3 for providing gas and a modifier injection source 9 for providing a modifier, as shown in figure 2. Wherein, the water pumping device 10, the air pressure source 3 and the modifier injection source 9 are connected with the graded conductive gas-guide tube. As shown in fig. 2, the anode 7 and the cathode 8 of the graded conductive gas-guide tube are uniformly distributed in the box body 1, and the pipeline 4 is arranged above the graded conductive gas-guide tube. The pipeline 4 is connected with an external power supply 2, a water pumping device 10, an air pressure source 3 and a modifier injection source 9; during operation, silt or soft soil is filled into the box body 1, the air guide hole 51 corresponding to the deepest level of the conductive tube 71 is exposed through the extraction sleeve 73 according to the method, gas and modifier are injected into the hierarchical conductive air guide tube through the air pressure source 3 and the modifier injection source 9, at the moment, the pipeline 4 serves as an air guide tube, the electrode hole 5 connected with the inner tube 72 serves as an air jet, the gas and the modifier are subjected to air pressure splitting through the air jet, a conductive crack and a modifier treatment layer are generated at the same time, the contact performance with the electrode is improved, and the energy utilization rate is improved. After the crack is generated, gas injection is stopped, electroosmosis consolidation is started, an external power supply 2 is started to be communicated with a primary conductive pipe 71 and a water pumping device 10, at the moment, a pipeline 4 is used as a water drainage pipe, an electrode hole 5 connected with an inner pipe 72 and a hole arranged on an outer pipe are used as water drainage holes, and under the action of voltage and the water pumping device 10, water enters a gap between the inner pipe 2 and a main pipe and the inner pipe 2 from the electrode hole 5 and is finally discharged through the water drainage pipe. Thereafter, the extraction casing 73 passes through the extraction casing 73 step by step, exposing the air vent 51 of the corresponding stage, and alternately performs air pressure splitting and electroosmotic drainage step by step on the soft soil, and when the electroosmotic drainage is performed, the power supply 2 turns on the stage and all the conductive pipes 71 in front of the stage, and simultaneously performs electroosmotic drainage, as shown in fig. 2.

In addition, the invention also provides a deep soft foundation treatment method for field construction of bottom-up graded electroosmotic drainage based on 'electrode movement', which specifically comprises the following steps:

(1) leveling the field: the deep and thick soft foundation field to be treated is leveled, and meanwhile, drainage ditches which are convenient for timely draining the water in the field are dug out from the periphery of the field, and the field is formed with a certain drainage gradient.

(2) A graded conductive air duct is arranged: and uniformly distributing and selecting distribution point positions of the hierarchical conductive gas-guide tubes in the field according to design requirements, and then striking the hierarchical conductive gas-guide tubes to the design depth at each distribution point position.

(3) Arranging an electroosmosis device, connecting an external power supply 2 and a water pumping device 10 with the hierarchical conductive gas-guide tube, and arranging a lead line and a water drainage and gas exhaust line connected with the hierarchical conductive gas-guide tube; and then the air pressure source 3 and the modifier injection source 9 are connected with the graded conductive gas-guide tube through a water discharge pipeline and a gas discharge pipeline.

(4) As shown in fig. 2, firstly, the extraction sleeve 73 exposes the deepest inner tube 72 hole, the air pressure source and the modifier injection source are opened to carry out air pressure splitting to generate cracks in soil around the electrode, the cracks are filled with water and modifier with conductive performance, after the soil around the cracks is solidified, the power supply of the first-stage conductive tube 71 is connected, the water pumping device is opened, and electroosmotic drainage of the soil around the first stage is carried out until the soil is solidified. The extraction sleeve 73 gradually exposes the inner pipe 72 hole of each stage, and the air injection splitting and the electroosmosis consolidation are alternately performed step by step.

(5) And finishing construction until the drainage consolidation is finished.

The common methods of electrode inversion, intermittent energization and step-by-step pressurization, which reduce energy consumption and improve electroosmosis reinforcement effect, can also be applied to the 'moving electrode' method. Preferably, in the electroosmosis process, working methods such as intermittent electrification, electrode inversion and intermittent air pressure splitting are carried out according to the actual drainage condition, and the intermittent time and the splitting position are determined according to the soil body dehydration condition.

In the method and the device, the air pressure source 3 is a device capable of stably providing air, such as an air compressor, an air bottle and the like. The modifier injection source 9 is a device for stably supplying a modifier, such as a sprayer or the like. Or the air pressure source 3 is connected with an atomizing device, the modifier and the air are mixed in the atomizing device to form aerosol, and the aerosol is then introduced into the graded conductive air duct.

The invention can also be simultaneously implemented by combining other construction methods, such as preloading or vacuum preloading and the like. When in preloading, a sand cushion is covered on the silt soil, and the preloading soil is applied. During vacuum preloading, a vacuum sealing film is covered on silt soil, an air suction pump is matched for air suction, and a pipeline in the process can be used together with an electroosmosis drainage pipeline to realize electroosmosis combined vacuum preloading drainage. When the fracturing crack area is used in combination with a vacuum preloading construction method, the modified fracture crack area can still maintain high permeability, can serve as a drainage layer, reduce the vacuum preloading attenuation coefficient, improve the transmission performance of vacuum pressure and accelerate sludge dewatering.

The invention provides an electrode moving electroosmosis construction method combined with ' bottom-up ' layer-by-layer ventilation ', which combines an electroosmosis consolidation method of layer-by-layer electrification and can achieve better dehydration effect on deep silt soft soil.

The expansion, morphology and stability of the crevice are important bases for the success of "moving electrode" electroosmosis. And the crack development, form and expansion range, the crack stability, the crack closing time and the like can be determined by modifying air pressure splitting parameters such as different air jet hole intervals, distribution shapes, air jet pressure, air jet quantity, air jet intervals and the like.

The electrode arrangement form of the conventional electroosmosis method is excellent in quincunx arrangement effect, and comprehensive effects such as air pressure splitting influence range are considered, so that different electrode plane arrangement forms can be changed, arrangement of rectangles, triangles, hexagons and the like is adopted, as a preferable scheme, when sludge soft soil is drained and reinforced in an outdoor place, the graded conductive air guide tubes and the lead wires can be arranged according to the rectangles or the quincunx, and holes of the adjacent graded conductive air guide tubes can be arranged in a staggered mode, as shown in fig. 2.

The above description is only an embodiment of the present invention, and it should be noted that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the protection scope of the present invention.

Claims (9)

1. A bottom-up classification electroosmosis drainage deep and soft foundation treatment method based on 'electrode movement' is characterized in that the method sequentially performs electroosmosis drainage from bottom to top, wherein each stage of electroosmosis drainage comprises air pressure splitting and electroosmosis construction steps; the air pressure splitting process comprises the following steps: injecting gas and a modifier with electric conductivity into the hierarchical conductive gas-guide tube, wherein the gas is sprayed from the holes to enable soil around the electrode to generate cracks, and the modifier is filled into the soil along the cracks to enable the soil around the cracks to be solidified and to be conductive; the hierarchical type conductive gas-guide tube is composed of a main tube, an inner tube (72) and a sleeve (73) which are coaxially sleeved, the main tube is composed of a plurality of sections of conductive tubes (71), the conductive tubes (71) are connected through a non-conductive joint (74), through holes are formed in the surfaces of the main tube and the inner tube (72), the number of the holes in the inner tube (72) is less than that of the main tube, and the holes in the inner tube (72) are communicated with the holes in the main tube through hole channels; the sleeve (73) is tightly attached to the inner wall of the inner pipe (72), and each section of the conductive pipe (71) is a first stage.

2. A bottom-up graded electroosmotic drainage deep soft foundation treatment process according to claim 1, wherein the modifier comprises a curing agent and a flocculant having conductive properties.

3. A bottom-up graded electroosmotic drainage deep and thick soft foundation treatment method according to claim 1, wherein the inner pipe (72) is provided with openings every 1m along the pipe axis direction, and each opening position is provided with 4 holes with the hole diameter of 2-5mm at equal intervals along the pipe wall ring direction.

4. The bottom-up graded electro-osmotic drainage deep and soft foundation treatment method according to claim 1, wherein the modifier is mixed with gas to form aerosol, and then the aerosol is introduced into the graded conductive gas-guide tube.

5. A bottom-up graded electroosmotic drainage deep soft foundation treatment method according to claim 1, wherein in the electroosmosis process, an intermittent electroosmosis, an intermittent air pressure splitting and/or an electrode reversal process is performed.

6. An electroosmotic consolidation apparatus based on the method of claim 1, comprising a housing (1), a staged conducting gas tube disposed in the housing (1), an external power source (2) for supplying stable power to the staged conducting gas tube, a water pumping device (10), a gas pressure source (3) for supplying gas, and a modifier injection source (9) for supplying modifier; the water pumping device (10), the air pressure source (3) and the modifier injection source (9) are connected with the graded conductive gas-guide tube through pipelines.

7. An electroosmotic consolidation apparatus according to claim 6, further comprising a preloading device or a vacuum preloading device.

8. A sludge dewatering or soft foundation treatment method for field construction based on bottom-up grading of 'electrode movement' is characterized by comprising the following steps:

(1) leveling the field: flattening a to-be-treated soft soil body field, and digging drainage ditches around the field to conveniently drain field water in time, wherein the field is optimally formed with a certain drainage gradient;

(2) a graded conductive air duct is arranged: uniformly distributing and selecting drainage distribution points in the field according to design requirements, and then striking the graded conductive gas guide pipe to the design depth at each distribution point;

(3) arranging an electroosmosis device, connecting an external power supply (2) and a water pumping device (10) with the hierarchical conductive gas-guide tube, and arranging a lead line and a water drainage and gas exhaust line connected with the hierarchical conductive gas-guide tube; then the air pressure source (3) and the modifier injection source (9) are connected with the graded conductive gas-guide tube through a drainage pipeline and a gas exhaust pipeline;

(4) firstly, an inner tube (72) hole at the deepest stage is exposed out of an extraction sleeve (73), an air pressure source (3) and a modifier injection source (9) are opened to carry out air pressure splitting to generate cracks in soil around an electrode, the cracks are filled with water and a modifier with electric conductivity, after the soil around the cracks is solidified, a power supply of a first-stage conductive tube (71) is connected, a water pumping device (10) is opened to carry out electroosmotic drainage on the soil around the first stage until the soil around the first stage is solidified;

(5) the extraction sleeve (73) gradually exposes out the holes of the inner pipe (72) of each stage, and electroosmotic drainage is gradually carried out according to the method of the step 4, so that the bottom-up graded electroosmotic drainage consolidation work is completed.

9. The bottom-up graded on-site sludge dewatering or soft foundation treatment method according to claim 8, wherein in the step (4), the preloading is performed in combination with vacuum preloading in which a sand cushion is coated on the sludge soil and a vacuum sealing film is coated on the sludge soil.

Images