Rapid dehydration device and dehydration method for road subgrade filler by using over-wet soft soil
Technical Field
The invention relates to the technical field of road engineering, in particular to a rapid dehydration device and a dehydration method for using over-wet soft soil for road bed filler.
Background
The soft soil can be subdivided into soft cohesive soil, mucky soil, silt, peat soil, peat and the like, and has the characteristics of high natural water content, large natural pore ratio, high compressibility, low shear strength, small consolidation coefficient, long consolidation time, high sensitivity, high disturbance, poor water permeability, complex layered distribution of soil layers, large difference of physical and mechanical properties among layers and the like. The standard for road engineering technology (JTGB01-2014) specifies: the soft soil is strictly prohibited to be directly used as roadbed filling, and curing improvement treatment is needed when the soft soil is required to be used as the roadbed filling. The over-wet soft soil of the present invention is defined as: the natural water content of the soft soil is more than 20 percent, and exceeds the upper limit value required by the soil as roadbed filling specified in the specification, and the soft soil can be used for improving the solidified soft soil after dehydration treatment; in recent years, with the rapid development of economic construction in coastal areas, soft soil is used as roadbed filler in road engineering, and because the surface of soft soil particles has negative charges and electrostatic attraction to water molecules, the activity and the mobility of a large number of water molecules around soil particles are reduced, and the soft soil particles can be subdivided into the following steps according to the different distances from the adsorbed water molecules to the particle surfaces: strongly bound water, weakly bound water, capillary free water, free water; the smaller the soft soil particles are, the higher the electromotive potential and the thermodynamic potential on the particle surface are, the stronger the capacity of adsorbing combined water is, and the larger the humidity of the soft soil is.
The conventional dehydration process can only separate free water and a few parts of weak bound water at present; the dehydration is not thorough, so that the soft soil has overlarge humidity, and the utilization rate of the roadbed filling material is low; at present, no matter a high-molecular organic curing agent is added, or inorganic binders such as cement, lime, fly ash and gypsum are added, and the target water content required by road filling engineering can not be achieved all the time within the range of expected economic mixing amount; the large proportion of the admixture leads to the continuous high construction cost.
Disclosure of Invention
The first technical problem to be solved by the present invention is to provide a quick dewatering device for over-wet soft soil particles, which aims at the above-mentioned prior art.
The second technical problem to be solved by the present invention is to provide a method for implementing rapid dehydration of over-wet soft soil particles by applying the above device in view of the above prior art.
The technical scheme adopted by the invention for solving the first technical problem is as follows: this cross wet weak soil is used for quick dewatering device of road bed filler, its characterized in that: comprises the following steps:
a tank for containing over-wet soft soil to be treated;
a vacuum pump connected at a lower end region of the tank for establishing a negative pressure within the tank and for powering the delivery of water and air fluids exiting the tank through the outlet opening;
a drain pipe connected to the vacuum pump and capable of generating a negative pressure, the drain pipe having a lower end connected to a lower end region of the tank; wherein the tank body has at least one flow channel at a lower end region fluidly connecting the tank body and the pipeline, water in the excessively wet soft soil to be treated will flow into the flow channel along the drain pipe under the action of vacuum negative pressure adsorption force of the drain pipe;
the vibrators are arranged on two sides of the box body; and
and the high-speed centrifugal device is arranged at the bottom of the box body.
Further, the top of the box body is provided with an air inlet, and an external air inlet pipe injects high-pressure gas into the box body through the air inlet.
After the over-wet soft soil is subjected to high-frequency vibration and high-speed centrifugation and vacuum negative pressure cooperative rapid dehydration, soil particles and water of the over-wet soft soil are in a state of being difficult to separate, high-pressure airflow is input into the over-wet soft soil to be treated through an external air inlet pipe through an air inlet to form a continuous and stable airflow field, the water content of the over-wet soft soil is further reduced by means of the strong wind field effect formed by a plurality of vertical drainage pipes, and the ultrahigh water content of the over-wet soft soil is reduced to the range of the water content required by roadbed filling materials.
Furthermore, the wall of the drainage pipe is provided with at least four rows of through holes for water in the over-wet soft soil to flow into the drainage pipe. After the drainage pipe is vacuumized, the water in the over-wet soft soil can effectively flow into the through hole for dehydration.
Further, the outer surface of the drain pipe is covered with gauze for filtering. The gauze not only can be used as a percolation film, but also can be used for avoiding the blockage of the through hole caused by over-wet soft soil in the dehydration process.
Preferably, the mesh number of the gauze is 80-200 meshes.
The invention provides a method for efficiently dehydrating over-wet and over-wet soft soil by using the rapid dehydration device for the over-wet soft soil for the roadbed filling material, which is used for solving the second technical problem, and is characterized in that: the method comprises the following steps:
(1) determining the distance between drain pipes, the vacuum degree, the vacuum pumping time, the vibration frequency, the vibration force and the vibration frequency parameters of a vibrator and the time of a high-speed centrifugal device by calculation according to the over-wet soft soil to be treated;
(2) keeping the box body parallel to the ground, and enabling each drain pipe in the box body to be vertically arranged; the lower end of each drain pipe is connected to the lower end area of the box body and an externally connected vacuum pump;
(3) putting the over-wet soft soil to be treated into a box body, and injecting a liquid high-efficiency nano-particle dispersing agent into each vertical drainage pipe; starting vibrators on two sides of the box body, applying vibration load to the peripheral wall of the box body filled with the over-wet soft soil to be treated and the liquid-state high-efficiency nano-particle dispersing agent, and promoting the high-efficiency nano-particle dispersing agent to diffuse into the over-wet soft soil through the integral vibration of the box body by vibration energy;
(4) starting a high-speed centrifugal device at the bottom, applying centrifugal force to the box body, further accelerating liquefaction of over-wet soft soil in the box body, and realizing rapid reduction of adsorption potential on the surfaces of over-wet soft soil particles and releasing more weak binding water by means of the liquefaction of the over-wet soft soil;
(5) when the water overflow phenomenon occurs on the top surface of the over-wet soft soil in the box body, the soil body is liquefied, an external vacuum pump is started, the bottom area of the box body is vacuumized through a drain pipe, a high-speed centrifugal device is reversely started, and the efficient dehydration of the over-wet soft soil is realized under the synergistic effect of vacuum negative pressure adsorption force and high-speed centrifugal force;
(6) when the water yield is less than the preset requirement, closing the vibrator and the vacuum pump, starting the high-pressure air pump at the moment, injecting high-pressure air into the over-wet soft soil to be treated through an external air inlet pipe and an air inlet at the top of the box body, forming a continuous and stable airflow field inside the dehydrated over-wet soft soil, and further reducing the bound water of the over-wet soft soil by means of a strong wind field effect formed by a plurality of vertical drainage pipes;
(7) after high-pressure gas injection is carried out for 2-5 minutes, the high-pressure gas pump is closed;
(8) restarting the external vacuum pump, vacuumizing the bottom of the device through the drain pipe, restarting the high-speed centrifugal device in a reverse direction, and realizing secondary efficient dehydration on the over-wet soft soil under the synergistic effect of the vacuum negative pressure adsorption force and the high-speed centrifugal force;
(9) determining whether to perform top high-pressure gas injection, bottom high-pressure centrifugation and vacuum pumping for the third time according to the condition of the dehydration humidity; and when the water content of the dehydrated over-wet soft soil meets the preset requirement, transferring the dehydrated over-wet soft soil in the box body to a formulated place for stacking for physical or chemical solidification improvement in the subsequent steps.
Further, the ratio of the liquid high-efficiency nanoparticle dispersing agent in the step (3) added into the soft soil is as follows: injecting 15-30 parts of macromolecular nano-soil particle dispersing agent into 100 parts of soft soil, wherein the concentration of the liquid high-efficiency nano-particle dispersing agent is 2-5%.
Furthermore, the proportion of the polymer nano soil particle dispersing agent permeation diluent is that every 100 parts of diluent contains 15-25 parts of phosphate, 40-60 parts of polymer nano modifier and 25-35 parts of active stabilizer.
Further, the phosphate is a single component or a mixture of several components of sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate and iron phosphate; the macromolecular nano modifier is a salt single component of alkylamine and amide or a mixture of the alkylamine and the amide; the active stabilizer is 2% of slaked lime water or 0.05% of metal soap water. Among them, the metallic soap water of the present invention refers to metallic salt water of higher fatty acid. The alkylamine is trialkylamine salt, and the amide is formamide salt.
Further, the polymer nano modifier is a polymer nano modifier formed by mixing a trialkylamine salt and a formamide salt or two of the trialkylamine salt and the formamide salt according to the concentration of 1:1, and the hydrophilic-lipophilic balance value of the mixed polymer nano modifier is 10-20.
Compared with the prior art, the invention has the advantages that: the hydrogen ion potential of polar water molecules is replaced by adding nano soil particle dispersant diluent to release more weak binding water, the pore water pressure promoted by high-frequency vibration destroys the micro ink bottle pore structure among soft soil particles to form a pore water drainage channel, the micro ink bottle is directly dehydrated by utilizing high-speed centrifugation and vacuum negative pressure rapid dehydration equipment, a continuous stable airflow field is formed inside the dehydrated over-wet soft soil by utilizing high-pressure airflow, the water content of the over-wet soft soil is further reduced by relying on the strong wind field effect formed by a plurality of vertical drainage pipes, the ultra-high water content of the over-wet soft soil is reduced to the water content range required by roadbed filling materials, and only nano soil particle dispersant diluent, mechanical consumption cost and a small amount of manual operation cost exist in the process; the rapid dehydration device and the rapid dehydration method have simple steps and high dehydration efficiency, and the dehydration device can be directly used for dehydration treatment on the highway subgrade filling construction site, thereby realizing the cost balance of the traditional method for filling the subgrade.
Drawings
FIG. 1 is a schematic view showing the construction of a rapid dehydration apparatus in embodiment 1 of the present invention;
FIG. 2 is a schematic view showing the structure of a drain pipe according to embodiment 1 of the present invention;
fig. 3 is a cross-sectional view of fig. 1.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
Example 1
As shown in fig. 1 to 3, the fast dewatering device for roadbed filling material through improved solidification after dewatering of over-wet soft soil has the following specific structure: the box 1 for containing the over-wet soft soil can be a container with closed peripheral wall, the container can be a hollow cylinder, a hollow square cylinder, a hollow rectangular cylinder or a groove with an upward opening, the top of the box 1 is detachably connected with a piston type top cover, an air inlet 11 at the top of the box 1 is arranged on the top cover, an external air inlet pipe injects high-pressure air into the over-wet soft soil through the air inlet 11, the lower end area 11 of the box 1 is provided with a vacuum pipe connected with an external vacuum pump 2, the vacuum pump 2 is arranged at the lower end area 11 of the box 1, and provides power for the transportation of water and air fluid which are used for establishing negative pressure in the box 1 and are separated from the box 1 through an outlet opening through a vacuum suction pipe, wherein the box 1 is provided with at least one flow channel 12 which is used for fluidly connecting the box 1 and pipelines at the lower end area 11, flow passages 12 for fluids such as air and water; the box body 1 is also internally provided with a matrix of water discharge pipes 3, and each water discharge pipe 3 is used for conveying the over-wet soft soil in the box body 1 to a flow channel 12 of a lower end area 11 of the box body 1 after the over-wet soft soil is separated by vacuum negative pressure under the vacuumizing action of the vacuum pump 2; in addition, the dewatering device also comprises a digital display variable frequency vibrator 4 connected to two sides of the peripheral wall of the box body 1 and a high-speed centrifugal rotating device arranged at the bottom of the box body 1, when the vacuum dewatering effect is not obvious, the high-speed centrifugal and vacuum negative pressure quick dewatering device can be started to dewater directly, high-pressure gas is injected into the over-wet soft soil body through the air inlet 11 by utilizing an external air inlet pipe, so that the high-pressure gas flow forms a continuous and stable airflow field inside the dewatered over-wet soft soil, the strong wind field effect formed by a plurality of vertical drain pipes 3 is relied on, the moisture content of the over-wet soft soil is further reduced, and the ultrahigh moisture content of the over-wet soft soil is reduced to the range of.
The relation between the height H of the drain pipe 3 in the specific dehydration device and the height H of the box body 1 satisfies the following conditions: h is 0.8H-0.95H, the diameter of the outer wall of each drain pipe 3 is 2-3 cm, the wall thickness is 3-5 mm, the aperture of each through hole 31 on the pipe wall of each drain pipe 3 is 3-6 mm, and the distance delta d between every two adjacent drain pipes 3 is 5 cm; the vibration frequency of the digital display vibrator 4 is 28-50 HZ, and the vibration time is 2-5 min; the high-speed centrifugal device 5 has the centrifugal rotating speed of 500-1800 rpm for 2-5 min; the dehydration time of the dehydration device is 8-20 min;
when in use, the over-wet soft soil is firstly put into the cavity of the box body 1 through the grab bucket of the excavator, then the dehydration device is used for vacuum water pumping, the main free water, capillary water and part of weak combined water in the over-wet soft soil are discharged through the water discharge pipe 3, the vibrator 4 and the high-speed centrifugal device 5 can be started to jointly dewater, when the direct vacuum pumping effect is not obvious, high-pressure gas is injected into the over-wet soft soil body through the gas inlet 11 by utilizing an external gas inlet pipe, so that the high-pressure airflow forms a continuous and stable airflow field in the dehydrated over-wet soft soil, the water content of the over-wet soft soil is further reduced, the ultrahigh water content of the over-wet soft soil is reduced to the range of the water content required by the roadbed filling material, and when the dehydration treatment is carried out after a certain time till the requirement is met, and opening the top cover, and moving the dehydrated over-wet soft soil in the box body 1 to a designated place for stacking for physical or chemical solidification improvement in the subsequent steps.
Example 2
A dewatering treatment method for treating excessively wet soft soil using the dewatering device of embodiment 1, the method comprising the steps of:
(1) the distance between the water discharge pipes 3, the vacuum degree, the vacuum pumping time, the vibration frequency, the vibration force and the vibration frequency parameters of the vibrator 4 and the time of the high-speed centrifugal device 5 are determined by calculation according to the over-wet soft soil to be treated;
(2) keeping the box body 1 parallel to the ground, and enabling each drain pipe 3 to be vertically arranged; the lower ends of the drain pipes 3 are connected to the lower end area 31 of the box body 1 and the suction vacuum pipe of the vacuum pump 2;
(3) putting the over-wet soft soil to be treated into the box body 1 through a grab bucket of an excavator, and injecting a liquid high-efficiency nano-particle dispersing agent into each vertical drain pipe 3; starting a bottom vibrator 4, applying a vibration load to the peripheral wall of the box body 1 filled with the over-wet soft soil to be treated and the liquid high-efficiency nano-particle dispersing agent, and promoting the high-efficiency nano-particle dispersing agent to diffuse into the over-wet soft soil by the vibration energy through the integral vibration of the box body 1; adding 15 parts of polymer nano-soil particle dispersant permeation diluent into over-wet soft soil with the soft soil adding proportion of 100 parts by volume, wherein the concentration of the liquid high-efficiency nano-particle dispersant is 2%, and the proportion of the polymer nano-soil particle dispersant permeation diluent is that each 100 parts of diluent contains 15 parts of phosphate, 40 parts of polymer nano-dispersant and 25 parts of active stabilizer, wherein the phosphate is single components of sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate and iron phosphate or a mixture of several of the components; the polymer nano modifier is a salt single component of alkylamine and amide or a mixture of the alkylamine and the amide; the active stabilizer is 2% of slaked lime water; the hydrophilic-lipophilic balance value of the macromolecular nano modifier is 10, and the concentration of the liquid high-efficiency nano particle dispersant is 2%.
(4) The bottom high-speed centrifugal device 5 is started to apply centrifugal force to the box body 1, so that the liquefaction phenomenon of the over-wet soft soil in the box body 1 is further accelerated, and the adsorption potential on the surfaces of over-wet soft soil particles is quickly reduced by means of the liquefaction of the over-wet soft soil, so that more weak bound water is released;
(5) when the water overflow phenomenon occurs on the top surface of the over-wet soft soil in the box body 1, the soil body is liquefied, a vacuum pump 2 at the bottom of the device is started, the vacuum is pumped through a drain pipe 3, a high-speed centrifugal device 5 is reversely started, and the efficient dehydration of the over-wet soft soil is realized under the synergistic effect of vacuum negative pressure adsorption force and high-speed centrifugal force;
(6) when the water yield is less than the preset requirement, closing the bottom vibrator 4 and the vacuum pump 2, starting the high-pressure air pump at the moment, injecting high-pressure air into the over-wet soft soil to be treated through an external air inlet pipe through an air inlet 11 at the top of the box body 1, forming a continuous and stable airflow field in the dehydrated soft soil, and further reducing the water content of the over-wet soft soil by means of a strong wind field effect formed by a plurality of vertical drain pipes 3;
(7) after high-pressure gas injection is carried out for 2-5 minutes, the high-pressure gas pump is closed;
(8) restarting a vacuum pump 2 at the bottom of the device, vacuumizing through a drain pipe 3, restarting a high-speed centrifugal device 5 in a reverse direction, and realizing secondary efficient dehydration of the over-wet soft soil under the synergistic effect of vacuum negative pressure adsorption force and high-speed centrifugal force;
(9) determining whether to perform top high-pressure gas injection, bottom high-pressure centrifugation and vacuum pumping for the third time according to the condition of the dehydration humidity; when the water content of the dewatered soft soil reaches the preset requirement, the soft soil treated in the box body 1 is moved to a specified place to be stacked for physical or chemical solidification improvement of the subsequent steps.
Example 3
A dewatering treatment method for treating excessively wet and excessively wet soft soil using the dewatering device of embodiment 1, the method comprising the steps of:
(1) the distance between the water discharge pipes 3, the vacuum degree, the vacuum pumping time, the vibration frequency, the vibration force and the vibration frequency parameters of the vibrator 4 and the time of the high-speed centrifugal device 5 are determined by calculation according to the over-wet and over-wet soft soil to be treated;
(2) keeping the box body 1 parallel to the ground, and enabling each drain pipe 3 to be vertically arranged; the lower ends of the drain pipes 3 are connected to the lower end area 31 of the box body 1 and the vacuum pump 2;
(3) placing the over-wet and over-wet soft soil to be treated into the box body 1 through a grab bucket of an excavator, and injecting a liquid efficient nanoparticle dispersing agent into each vertical drain pipe 3; starting a bottom vibrator 4, applying a vibration load to the peripheral wall of the box body 1 filled with the over-wet soft soil to be treated and the liquid high-efficiency nano-particle dispersing agent, and promoting the high-efficiency nano-particle dispersing agent to diffuse into the over-wet soft soil by the vibration energy through the integral vibration of the box body 1; 30 parts of polymer nano-soil particle dispersant permeation diluent is injected into 100 parts of soft soil with the volume ratio of over-wet soft soil, the concentration of the liquid high-efficiency nano-soil particle dispersant is 5%, the proportion of the polymer nano-soil particle dispersant permeation diluent is that every 100 parts of diluent contains 25 parts of phosphate, 60 parts of polymer nano-soil dispersant and 35 parts of active stabilizer, wherein the phosphate is single components of sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate and iron phosphate or a mixture of several of the components; the polymer nano modifier is a salt single component of alkylamine and amide or a mixture of the alkylamine and the amide; the active stabilizer is 0.05 percent of metal soap water; the hydrophilic-lipophilic balance value of the macromolecular nano modifier is 20, and the concentration of the liquid high-efficiency nano particle dispersant is 3%.
(4) The bottom high-speed centrifugal device 5 is started to apply centrifugal force to the box body 1, so that the liquefaction phenomenon of over-wet soft soil in the box body 1 is further accelerated, the adsorption potential on the surface of soft soil particles is quickly reduced by virtue of the liquefaction of the soft soil, and more weak bound water is released;
(5) when the water overflow phenomenon occurs on the top surface of the over-wet soft soil in the box body 1, the soil body is liquefied, a vacuum pump 2 at the bottom of the device is started, the vacuum is pumped through a drain pipe 3, a high-speed centrifugal device 5 is reversely started, and the efficient dehydration of the over-wet soft soil is realized under the synergistic effect of vacuum negative pressure adsorption force and high-speed centrifugal force;
(6) when the water yield is less than the preset requirement, closing the bottom vibrator 4 and the vacuum pump 2, starting the high-pressure air pump at the moment, injecting high-pressure air into the over-wet soft soil to be treated through an external air inlet pipe and an air inlet 11 at the top of the box body 1, forming a continuous and stable airflow field inside the dehydrated over-wet soft soil, and further reducing the water content of the soft soil by means of a strong wind field effect formed by a plurality of vertical drain pipes 3;
(7) after high-pressure gas injection is carried out for 2-5 minutes, the high-pressure gas pump is closed;
(8) restarting a vacuum pump 2 at the bottom of the device, vacuumizing through a drain pipe 3, restarting a high-speed centrifugal device 5 in a reverse direction, and realizing secondary efficient dehydration of the over-wet soft soil under the synergistic effect of vacuum negative pressure adsorption force and high-speed centrifugal force;
(9) determining whether to perform top high-pressure gas injection, bottom high-pressure centrifugation and vacuum pumping for the third time according to the condition of the dehydration humidity; when the water content of the dehydrated over-wet soft soil meets the preset requirement, the soft soil treated in the box body 1 is moved to a specified place to be stacked for physical or chemical solidification improvement in the subsequent steps.
Example 4
A dewatering treatment method for treating excessively wet soft soil using the dewatering device of embodiment 1, the method comprising the steps of:
(1) the distance between the water discharge pipes 3, the vacuum degree, the vacuum pumping time, the vibration frequency, the vibration force and the vibration frequency parameters of the vibrator 4 and the time of the high-speed centrifugal device 5 are determined by calculation according to the over-wet soft soil to be treated;
(2) keeping the box body 1 parallel to the ground, and enabling each drain pipe 3 to be vertically arranged; the lower ends of the drain pipes 3 are connected to the lower end area 31 of the box body 1 and the vacuum pump 2;
(3) putting the over-wet soft soil to be treated into the box body 1 through a grab bucket of an excavator, and injecting a liquid high-efficiency nano-particle dispersing agent into each vertical drain pipe 3; starting a bottom vibrator 4, applying a vibration load to the peripheral wall of the box body 1 filled with the soft soil to be treated and the liquid-state high-efficiency nano-particle dispersing agent, and promoting the high-efficiency nano-particle dispersing agent to diffuse into the over-wet soft soil by the vibration energy through the integral vibration of the box body 1; adding the liquid high-efficiency nano-particle dispersing agent into over-wet soft soil with the over-wet soft soil volume ratio of 100 parts, injecting 25 parts of polymer nano-particle dispersing agent permeation diluent, wherein the concentration of the liquid high-efficiency nano-particle dispersing agent is 3%, and the proportion of the polymer nano-particle dispersing agent permeation diluent is that each 100 parts of the diluent contains 20 parts of phosphate, 50 parts of polymer nano-particle dispersing agent and 28 parts of active stabilizer, wherein the phosphate is a single component or a mixture of several components of sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate and iron phosphate; the polymer nano modifier is a salt single component of alkylamine and amide or a mixture of the alkylamine and the amide; the active stabilizer is 2% of slaked lime water; the hydrophilic-lipophilic balance value of the macromolecular nano modifier is 15, and the concentration of the liquid high-efficiency nano particle dispersant is 5%.
(4) The bottom high-speed centrifugal device 5 is started to apply centrifugal force to the box body 1, so that the liquefaction phenomenon of the over-wet soft soil in the box body 1 is further accelerated, and the adsorption potential on the surfaces of over-wet soft soil particles is quickly reduced by means of the liquefaction of the over-wet soft soil, so that more weak bound water is released;
(5) when the water overflow phenomenon occurs on the top surface of the over-wet soft soil in the box body 1, the soil body is liquefied, a vacuum pump 2 at the bottom of the device is started, the vacuum is pumped through a drain pipe 3, a high-speed centrifugal device 5 is reversely started, and the efficient dehydration of the over-wet soft soil is realized under the synergistic effect of vacuum negative pressure adsorption force and high-speed centrifugal force;
(6) when the water yield is less than the preset requirement, closing the bottom vibrator 4 and the vacuum pump 2, starting the high-pressure air pump at the moment, injecting high-pressure air into the over-wet soft soil to be treated through an external air inlet pipe and an air inlet 11 at the top of the box body 1, forming a continuous and stable airflow field inside the dehydrated over-wet soft soil, and further reducing the water content of the over-wet soft soil by means of a strong wind field effect formed by a plurality of vertical drain pipes 3;
(7) after high-pressure gas injection is carried out for 2-5 minutes, the high-pressure gas pump is closed;
(8) restarting a vacuum pump 2 at the bottom of the device, vacuumizing through a drain pipe 3, restarting a high-speed centrifugal device 5 in a reverse direction, and realizing secondary efficient dehydration of the over-wet soft soil under the synergistic effect of vacuum negative pressure adsorption force and high-speed centrifugal force;
(9) determining whether to perform top high-pressure gas injection, bottom high-pressure centrifugation and vacuum pumping for the third time according to the condition of the dehydration humidity; when the water content of the dehydrated over-wet soft soil meets the preset requirement, the soft soil treated in the box body 1 is moved to a specified place to be stacked for physical or chemical solidification improvement in the subsequent steps.