Equipment and construction methods for micro-nano CO2 carbonization reinforcement of weak foundations

Abstract

This invention belongs to the field of foundation treatment technology in civil engineering, specifically disclosing a device and construction method for micro-nano CO2 carbonization reinforcement of weak foundations. The device includes a main unit system, a micro-nano CO2 generation system, and a feeding system. It injects CO2 gas in the form of micro-nano bubbles into the mixing pile body of activated magnesium oxide and the weak foundation, maximizing the mass transfer and utilization efficiency of CO2 gas, thereby improving the reaction efficiency between CO2 gas and activated magnesium oxide. This effectively solves the problem of slow and uneven diffusion of CO2 gas within the mixing pile body in existing carbonization solidification technologies, shortening the foundation treatment period. Furthermore, this invention directly mixes the micro-nano CO2 bubble solution, activated magnesium oxide, and the weak foundation, eliminating the step of inserting vent pipes or permeable pipe piles into the mixing pile body in existing technologies, making construction more convenient and saving on foundation treatment costs.

Description

Technical Field

[0001] This invention belongs to the field of foundation treatment technology in civil engineering, and particularly relates to a device and construction method for micro-nano CO2 carbonization reinforcement of weak foundations. Background Technology

[0002] Currently, carbonation reinforcement technology for weak foundations based on the carbonization reaction of active magnesium oxide has developed rapidly, including methods such as carbonation mixing piles, integral carbonization, and composite foundation construction methods of carbonation mixing piles and permeable pipe piles. These methods can well meet the requirements for high pile strength and exhibit low-carbon, high-efficiency, and environmentally friendly characteristics, which are in line with the development trend of green construction in civil engineering.

[0003] However, these carbonation reinforcement technologies for weak foundations have gradually shown some limitations in engineering applications. For example, they are difficult to meet the reinforcement needs of deep, weak foundations when treating shallow foundations. Chinese invention patent CN106869120B discloses a carbonation mixing pile-permeable pipe pile composite foundation and its construction method. This is currently a widely used carbonation solidification method for weak foundations. The resulting composite foundation has high bearing capacity and reliable quality. However, the "secondary pile formation" construction process of this method is relatively cumbersome and has high construction costs.

[0004] While carbonation-mixing piles are convenient and cost-effective, the method directly uses the mixing shaft as a channel for CO2 gas, making it highly susceptible to gas leakage and secondary pollution. Furthermore, CO2 gas diffuses slowly and unevenly within the pile. Chinese invention patent CN103981854B discloses a treatment system and carbonation-mixing pile method for foundation reinforcement. This method attempts to use foam as a temporary medium for CO2 gas to enter the soil, which, while addressing CO2 leakage to some extent, generally results in poor foundation reinforcement.

[0005] In recent years, micro and nanobubbles have attracted much attention due to their unique physicochemical properties and potential applications. Compared to macroscopic bubbles, micro and nanobubbles have smaller diameters, larger specific surface areas, and self-pressurizing and dissolving properties, enabling them to effectively transfer gases into water and improve gas utilization efficiency and gas-liquid mass transfer efficiency. Furthermore, the gas inside micro and nanobubbles exists in a high-pressure, high-density aggregated state, exhibiting unique stability. Their slow bubble rise rate allows them to remain suspended stably in water for hours or even days, making them a relatively ideal medium for gas slow release and transport.

[0006] Therefore, combining the problems of the above-mentioned carbonization reinforcement technology for weak foundations with the unique advantages of micro-nano bubbles, this invention has developed a device and method for micro-nano CO2 carbonization reinforcement of weak foundations, which is of great significance for effectively avoiding secondary pollution, making full use of CO2 gas, and achieving efficient construction, low carbon emissions and environmental protection. Summary of the Invention

[0007] One objective of this invention is to provide a device for micro-nano CO2 carbonization reinforcement of weak foundations, which effectively solves the problem of slow and uneven diffusion of CO2 gas within the mixing pile body in existing carbonization reinforcement technology for weak foundations.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] A device for reinforcing weak foundations using micro-nano CO2 carbonization includes a main unit system, a micro-nano CO2 generating system, and a feeding system.

[0010] The main system includes a drill rod, an upper transmission device for driving the drill rod, a material conveying device, a control system for controlling the upper transmission device, a vertical frame, and a movable chassis. The vertical frame is mounted on the chassis, the control system is mounted on the vertical frame, the upper transmission device is located on the upper part of the vertical frame, the control system is connected to the upper transmission device, the drill rod is connected to the upper transmission device, and the material conveying device is located inside the upper transmission device. The material conveying device includes a liquid conveying channel and a powder conveying channel.

[0011] The drill rod includes a drill bit and a rod section. The rod section consists of an inner tube and an outer tube that are not interconnected. The inner tube is located inside the outer tube, and the outer diameter of the inner tube is smaller than the inner diameter of the outer tube. The bottom end of the outer tube is located above the bottom end of the inner tube. The bottom end of the outer tube is connected to the top end of the drill bit. The inner tube is inserted into the drill bit and extends to near the bottom end of the drill bit. The lower part of the outer tube is provided with a through-hole for liquid injection, and the lower part of the inner tube is provided with a through-hole for powder injection. The drill bit is provided with a through hole at a position corresponding to the powder injection hole.

[0012] The micro-nano CO2 generating system includes a CO2 storage tank, a micro-nano bubble generating device, a water storage tank, and a liquid pressurization device. The micro-nano bubble generating device includes an inlet, a first circulation inlet located at the bottom of the micro-nano bubble generating device, and a second circulation inlet located at the top of the micro-nano bubble generating device. The water storage tank includes a water storage tank inlet located on one side of the bottom of the water storage tank, a first water storage tank outlet located on the other side of the bottom of the water storage tank, and a second water storage tank outlet located at the top of the water storage tank.

[0013] The CO2 storage tank is connected to the inlet of the micro-nano bubble generator. The first circulation inlet of the micro-nano bubble generator is connected to the inlet of the water storage tank. The second outlet of the water storage tank is connected to the second circulation inlet of the micro-nano bubble generator. The first outlet of the water storage tank is connected to the inlet of the liquid pressurizing device. The outlet of the liquid pressurizing device is connected to the liquid delivery channel of the conveying device. The liquid delivery channel is connected to the outer pipe.

[0014] The feeding system includes a storage tank for storing powdered curing agent and a powder pressurizing device. The storage tank is connected to the inlet of the powder pressurizing device, the outlet of the powder pressurizing device is connected to the powder conveying channel of the conveying device, and the powder conveying channel is connected to the inner tube.

[0015] Furthermore, both the bottom ends of the inner tube and the outer tube are closed, and the inner tube extends downward through the bottom end of the outer tube to near the bottom end of the drill bit.

[0016] Furthermore, there are multiple powder spray nozzles and multiple liquid spray nozzles.

[0017] Furthermore, the powder spray nozzles are evenly arranged around the inner tube, and the liquid spray nozzles are evenly arranged around the outer tube.

[0018] Another objective of this invention is to provide a construction method for micro-nano CO2 carbonization reinforcement of weak foundations, which effectively solves the problem of slow and uneven diffusion of CO2 gas within the mixing pile body in existing carbonization reinforcement technology for weak foundations.

[0019] A construction method for reinforcing weak foundations with micro-nano CO2 carbonization, using the micro-nano CO2 carbonization equipment for reinforcing weak foundations described in the above embodiments, includes the following steps:

[0020] S1. Level the site;

[0021] S2, Drill pipe positioning;

[0022] Move the chassis and align the drill rod vertically with the designated pile position on the natural foundation;

[0023] S3. Preparation of micro / nano CO2 bubble solution;

[0024] Open the CO2 storage tank and start the micro-nano bubble generator to prepare a micro-nano CO2 bubble solution;

[0025] S4. Stir and let it settle;

[0026] The upper transmission device is activated by the control system to drive the drill rod into the set depth of the set pile position in the natural foundation.

[0027] S5, powder spraying, liquid spraying, stirring and lifting;

[0028] The control system controls the drill rod to the lifting state, activates the liquid pressurization device to deliver the micro-nano CO2 bubble solution to the outer tube and spray it out from the spray nozzle, and at the same time activates the powder pressurization device to deliver the powdered curing agent to the inner tube and spray it out from the powder spray nozzle, while spraying powder, stirring and lifting.

[0029] S6. Complete the forming of the mixing pile body and the soft foundation reinforcement is formed.

[0030] Furthermore, after the stirring and lifting described in step S5, the drill rod is re-stirred, and then lifted to the ground.

[0031] Furthermore, the powdered curing agent is active magnesium oxide powder.

[0032] The beneficial technical effects of the present invention are:

[0033] (1) In this invention, CO2 gas is injected into the mixing pile body of active magnesium oxide and soft foundation in the form of micro-nano bubbles, which maximizes the mass transfer efficiency and utilization efficiency of CO2 gas, further improves the reaction efficiency of CO2 gas and active magnesium oxide, effectively solves the problem of slow and uneven diffusion of CO2 gas in the mixing pile body in the existing carbonization and solidification technology, and shortens the foundation treatment period.

[0034] (2) The present invention directly mixes micro-nano CO2 bubble solution, active magnesium oxide and soft foundation to form a mixing pile body, which eliminates the step of inserting air pipe or air-permeable pipe pile into the mixing pile body in the prior art, making construction more convenient and saving the cost of foundation treatment.

[0035] (3) This invention uses active magnesium oxide to replace traditional Portland cement, while effectively utilizing greenhouse gas CO2, and has the advantages of energy saving, environmental protection and low carbon and high efficiency.

[0036] (4) This invention is applicable to deep foundation treatment and can meet the reinforcement of deep and weak foundation soil. Attached Figure Description

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0038] Figure 1 This is a schematic diagram of the device structure of the present invention;

[0039] Figure 2 yes Figure 1 A cross-sectional view of the drill pipe;

[0040] Figure 3 This is a schematic diagram of the construction method of the present invention. Detailed Implementation

[0041] Example 1

[0042] like Figure 1 As shown, a device for reinforcing weak foundations using micro-nano CO2 carbonization includes a main unit system, a micro-nano CO2 generating system, and a feeding system.

[0043] The main system includes a drill rod 1, an upper transmission device 2 for driving the drill rod 1, a material conveying device 3, a control system 4 for controlling the upper transmission device 2, a frame 5, and a movable chassis 6. In some specific embodiments, the chassis 6 moves by tracks.

[0044] The upright frame 5 is mounted on the chassis 6, the control system 4 is mounted on the upright frame 5, the upper transmission device 2 is mounted on the upper part of the upright frame 5, the control system 4 is connected to the upper transmission device 2, the drill rod 1 is connected to the upper transmission device 2, the material conveying device 3 is located inside the upper transmission device 2, and the material conveying device 3 includes a liquid conveying channel and a powder conveying channel.

[0045] In some specific embodiments, the upright frame 5 is connected in an L-shape by a transverse rod 51 and a longitudinal rod 52. The transverse rod 51 is fixed to the top of the chassis 6. The control system 4 is located at the free end of the transverse rod 51, and the upper transmission device 2 is located on the upper part of the longitudinal rod 52. To enhance the stability of the connection between the control system 4 and the upright frame 5, and between the transverse rod 51 and the longitudinal rod 52, a first support rod 53 is connected between the control system 4 and the longitudinal rod 52, and a second support rod 54 is connected between the first support rod 53 and the transverse rod 51.

[0046] like Figure 2 As shown, the drill rod 1 includes a drill bit 11 and a rod portion 12. The drill bit 11 is in the shape of an inverted cone. The rod portion 12 consists of an inner tube 7 and an outer tube 8 that are not interconnected. The inner tube 7 is located inside the outer tube 8. The outer diameter of the inner tube 7 is smaller than the inner diameter of the outer tube 8. The bottom end of the outer tube 8 is located above the bottom end of the inner tube 7. The bottom end of the outer tube 8 is connected to the top end of the drill bit 11. The inner tube 7 is inserted into the drill bit 11 and extends to near the bottom end of the drill bit 11.

[0047] In some specific embodiments, the bottom end of the inner tube 7 and the bottom end of the outer tube 8 are both closed, and the inner tube 7 extends downward through the bottom end of the outer tube 8 to near the bottom end of the drill bit 11.

[0048] The lower part of the outer tube 8 is provided with a through-hole 9, the lower part of the inner tube 7 is provided with a through-hole 10, and the drill bit 11 is provided with a through hole at a position corresponding to the powder injection port 10.

[0049] In some specific embodiments, a first short tube is connected to the liquid spraying port 9, and a second short tube is connected to the powder spraying port 10, with the second short tube extending outward from the through hole.

[0050] In some specific embodiments, there are multiple powder spraying nozzles 10 and liquid spraying nozzles 9. In particular, the powder spraying nozzles 10 are evenly arranged around the inner tube 7, and the liquid spraying nozzles 9 are evenly arranged around the outer tube 8.

[0051] The micro-nano CO2 generating system includes a CO2 storage tank 13, a micro-nano bubble generating device 14, a water storage tank 15, and a liquid pressurization device 16.

[0052] The micro / nano bubble generator 14 includes an inlet 141, a first circulation inlet 142 located at the bottom of the micro / nano bubble generator 14, and a second circulation inlet 143 located at the top of the micro / nano bubble generator 14.

[0053] The water storage tank 15 includes a water storage tank inlet 151 located on one side of the bottom of the water storage tank, a water storage tank first outlet 153 located on the other side of the bottom of the water storage tank, and a water storage tank second outlet 152 located on the top of the water storage tank 15.

[0054] The CO2 storage tank 13 is connected to the inlet 141 of the micro-nano bubble generator 14 via a gas delivery pipe. The first circulation inlet 142 of the micro-nano bubble generator 14 is connected to the inlet 151 of the water storage tank via a liquid outlet pipe. The second outlet 152 of the water storage tank is connected to the second circulation inlet 143 of the micro-nano bubble generator 14 via a liquid inlet pipe. The first outlet 153 of the water storage tank is connected to the inlet of the liquid pressurizing device 16 via a liquid delivery pipe. The outlet of the liquid pressurizing device 16 is connected to the liquid delivery channel of the conveying device 3, and the liquid delivery channel is connected to the outer pipe 8.

[0055] The feeding system includes a storage tank 17 for storing powdered curing agent and a powder pressurizing device 18. In some specific embodiments, the powdered curing agent is active magnesium oxide powder. By using active magnesium oxide to replace traditional Portland cement, and effectively utilizing greenhouse gas CO2, it has the advantages of energy saving, environmental protection, low carbon and high efficiency.

[0056] The storage tank 17 is connected to the inlet of the powder pressurizing device 18, the outlet of the powder pressurizing device 18 is connected to the powder conveying channel of the conveying device 3, and the powder conveying channel is connected to the inner tube 7.

[0057] Example 2

[0058] A construction method for reinforcing weak foundations using micro-nano CO2 carbonization, employing the equipment for micro-nano CO2 carbonization reinforcement of weak foundations described in Example 1, such as... Figure 3 As shown, it includes the following steps:

[0059] S1. Level the site.

[0060] S2, Drill pipe 1 positioning;

[0061] Move the chassis 6 and align the drill rod 1 vertically with the designated pile position of the natural foundation 19.

[0062] S3. Preparation of micro / nano CO2 bubble solution;

[0063] Open the CO2 storage tank 13 and start the micro-nano bubble generator 14. The micro-nano bubble generator 14 and the water storage tank 15 are connected in a loop to prepare micro-nano CO2 bubble solution.

[0064] S4. Stir and let it settle;

[0065] The upper transmission device 2 is activated by the control system 4 to drive the drill rod 1 to the set depth of the set pile position of the natural foundation 19.

[0066] S5, powder spraying, liquid spraying, stirring and lifting;

[0067] The control system 4 controls the drill rod 1 to the lifting state, starts the liquid pressurization device 16, and delivers the micro-nano CO2 bubble solution to the outer tube 8 and sprays it out from the spray nozzle 9. At the same time, the powder pressurization device 18 is started to deliver the powdered curing agent to the inner tube 7 and spray it out from the powder spraying nozzle 10. The powder is sprayed while stirring and lifting.

[0068] S6. Re-stir, and after re-stirring, lift drill rod 1 to the ground.

[0069] S7. Complete the forming of the mixing pile body 20, and reinforce the soft foundation.

[0070] The re-stirring in step S6 is to make the powdered curing agent and the micro-nano CO2 bubble solution more evenly dispersed in the stirring pile 20. This step can be decided whether to be carried out depending on the specific situation.

[0071] This invention injects CO2 gas in the form of micro-nano bubbles into the mixing pile body 20 of activated magnesium oxide and soft foundation, maximizing the mass transfer and utilization efficiency of CO2 gas, thereby improving the reaction efficiency between CO2 gas and activated magnesium oxide. This effectively solves the problem of slow and uneven diffusion of CO2 gas within the mixing pile body 20 in existing carbonization and solidification technologies, shortening the foundation treatment period. Furthermore, this invention directly mixes the micro-nano CO2 bubble solution, activated magnesium oxide, and soft foundation to form the mixing pile body 20, eliminating the need for inserting vent pipes or permeable pipe piles into the mixing pile body 20 in existing technologies, making construction more convenient and saving on foundation treatment costs.

[0072] For any parts not mentioned in this invention, existing technologies can be used or referenced.

[0073] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A device for reinforcing weak foundations using micro / nano CO2 carbonization, characterized in that, This includes the main unit system, the micro / nano CO2 generator system, and the feeding system; The main system includes a drill rod, an upper transmission device for driving the drill rod, a material conveying device, a control system for controlling the upper transmission device, a vertical frame, and a movable chassis. The vertical frame is mounted on the chassis, the control system is mounted on the vertical frame, the upper transmission device is mounted on the upper part of the vertical frame, the control system is connected to the upper transmission device, the drill rod is connected to the upper transmission device, and the material conveying device is located inside the upper transmission device. The material conveying device includes a liquid conveying channel and a powder conveying channel. The drill rod includes a drill bit and a rod section. The rod section consists of an inner tube and an outer tube that are not interconnected. The inner tube is located inside the outer tube, and the outer diameter of the inner tube is smaller than the inner diameter of the outer tube. The bottom end of the outer tube is located above the bottom end of the inner tube. The bottom end of the outer tube is connected to the top end of the drill bit. The inner tube is inserted into the drill bit and extends to near the bottom end of the drill bit. The lower part of the outer tube is provided with a through-hole for liquid injection, and the lower part of the inner tube is provided with a through-hole for powder injection. The drill bit is provided with a through hole at a position corresponding to the powder injection hole. The micro-nano CO2 generating system includes a CO2 storage tank, a micro-nano bubble generating device, a water storage tank, and a liquid pressurization device. The micro-nano bubble generating device includes an inlet, a first circulation inlet located at the bottom of the micro-nano bubble generating device, and a second circulation inlet located at the top of the micro-nano bubble generating device. The water storage tank includes a water storage tank inlet located on one side of the bottom of the water storage tank, a first water storage tank outlet located on the other side of the bottom of the water storage tank, and a second water storage tank outlet located at the top of the water storage tank. The CO2 storage tank is connected to the inlet of the micro-nano bubble generator, the first circulation inlet of the micro-nano bubble generator is connected to the inlet of the water storage tank, the second outlet of the water storage tank is connected to the second circulation inlet of the micro-nano bubble generator, the first outlet of the water storage tank is connected to the inlet of the liquid pressurizing device, the outlet of the liquid pressurizing device is connected to the liquid conveying channel of the conveying device, and the liquid conveying channel is connected to the outer pipe. The feeding system includes a storage tank for storing powdered curing agent and a powder pressurizing device. The storage tank is connected to the inlet of the powder pressurizing device, the outlet of the powder pressurizing device is connected to the powder conveying channel of the conveying device, and the powder conveying channel is connected to the inner tube.

2. The device for reinforcing weak foundations using micro / nano CO2 carbonization according to claim 1, characterized in that, The bottom ends of both the inner and outer tubes are closed, and the inner tube extends downward through the bottom end of the outer tube to near the bottom end of the drill bit.

3. The device for reinforcing weak foundations using micro / nano CO2 carbonization according to claim 2, characterized in that, There are multiple powder spray nozzles and multiple liquid spray nozzles.

4. The device for reinforcing weak foundations using micro / nano CO2 carbonization according to claim 3, characterized in that, The powder spray nozzles are evenly arranged around the inner tube, and the liquid spray nozzles are evenly arranged around the outer tube.

5. A construction method for reinforcing weak foundations using micro / nano CO2 carbonization, characterized in that, The device for reinforcing weak foundations using micro-nano CO2 carbonization as described in any one of claims 1-4 includes the following steps: S1. Level the site; S2, Drill pipe positioning; Move the chassis and align the drill rod vertically with the designated pile position on the natural foundation; S3. Preparation of micro / nano CO2 bubble solution; Open the CO2 storage tank and start the micro-nano bubble generator to prepare a micro-nano CO2 bubble solution; S4. Stir and let it settle; The upper transmission device is activated by the control system to drive the drill rod into the set depth of the set pile position in the natural foundation. S5, powder spraying, liquid spraying, stirring and lifting; The control system controls the drill rod to the lifting state, activates the liquid pressurization device to deliver the micro-nano CO2 bubble solution to the outer tube and spray it out from the spray nozzle, and at the same time activates the powder pressurization device to deliver the powdered curing agent to the inner tube and spray it out from the powder spray nozzle, while spraying powder, stirring and lifting. S6. Complete the forming of the mixing pile body and the soft foundation reinforcement is formed.

6. The construction method for reinforcing weak foundations using micro-nano CO2 carbonization according to claim 5, characterized in that, After stirring and lifting as described in step S5, the drill rod is stirred again and then lifted to the ground.

7. The construction method for micro-nano CO2 carbonization reinforcement of weak foundations according to claim 5 or claim 6, characterized in that, The powdered curing agent is active magnesium oxide powder.

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