Powder spraying pile powder conveying device, powder spraying pile construction system and control method

Abstract

The invention discloses a powder spraying pile powder conveying device, a powder spraying pile construction system and a control method. The conveying device mainly comprises a tank body, a gas circuit unit, a conveying pipeline, a feeding device, a mixer and a control unit, and an outlet of the tank body is connected to the feeding device, the mixer and the conveying pipeline; the peripheral wall of the mixer is connected with at least one gas inlet pipe; the gas circuit unit comprises a main gas supply pipe and at least one gas supply branch, an inlet of the main gas supply pipe is connected with the gas supply unit, an outlet of the main gas supply pipe is connected with the corresponding gas inlet pipes through the gas supply branches, and an outlet of the conveying pipeline is connected with the powder spraying pile drilling machine. And a dredging air supply branch and a pipeline pressure reducing device are further arranged at the bottom of the feeding device. According to the powder spraying pile powder conveying device, the powder spraying pile construction system and the control method, the conveying amount of the curing agent powder can be kept stable and uniform, the spraying pressure of the curing agent powder at the position of a spraying opening of a drill bit is guaranteed, and the feeding device and a conveying pipeline can be prevented from being blocked.

Description

Technical Field

[0001] The present invention relates to the technical field of construction of underground engineering powder jet mixing piles, and in particular to a powder jet pile powder material conveying device, a powder jet pile construction system and a control method. Background Art

[0002] Soft soil foundations are widespread in my country, particularly in areas surrounding oceans, lakes, and rivers, where soils have high moisture content, large void ratios, and high compressibility. Land development requires extensive soft soil treatment engineering for these soft soils. For nearly 70 years, traditional slurry-jet pile technology has been a common practice in civil engineering to reinforce these weak foundations. However, the strength and bearing capacity achieved using this slurry-jet pile construction technology and method often fail to meet design objectives.

[0003] To this end, Nordic countries have developed dry-mix pile technology, which uses a dry powder of a curing agent, such as lime or cement, to reinforce saturated soft soil foundations. This technology and method are particularly suitable for foundation soils with high moisture content, large void ratios, and high compressibility. Its application in civil engineering projects can effectively reinforce weak foundations. However, in actual engineering applications, powder injection pile technology still faces several technical challenges that need to be addressed. During the construction of powder spray piles, due to fluctuations in the delivery volume of the feeding background, the amount of curing agent added at different depths of the pile body becomes significantly uneven, which may even cause quality problems such as broken piles in severe cases. After long-term use, the traditional powder spray pile feeding background is prone to causing curing agent compaction and blockage at the discharge point, causing changes in the feeding volume, resulting in uneven feeding volume at different depths and poor pile quality. In addition, during the construction of powder spray piles, the traditional manual background control method has obvious operational defects. Due to the need for frequent manual intervention, not only is the operational error rate high, but when the powder spraying volume deviates by more than ±5%, manual adjustment often has a response delay of 8-10 seconds. This lag directly affects the molding quality of the pile body and is also extremely challenging to the sense of responsibility of the construction personnel. When the mixing drill nozzle is blocked from spraying powder inside the soil, the internal pressure of the conveying pipeline suddenly increases, which can easily cause pipe bursting. Summary of the Invention

[0004] In view of the characteristics of the existing powder spray pile feeding device and the technical problems it faces, the present invention proposes a powder spray pile powder conveying device, a powder spray pile construction system and a control method. By utilizing the background equipment to work in conjunction with the underground pressure monitoring device, the delivery amount of the curing agent powder can be kept stable and uniform, and the feeding pressure can be kept stable at all times. The specially designed mixer can greatly reduce the loss of conveying energy and ensure the injection pressure of the curing agent powder at the drill bit nozzle position. The control unit is used to perform intelligent and automatic control of the feeding device to meet the needs of various stages of construction and ensure the overall high-quality construction of the powder spray pile. At the same time, the setting of the dredging pipe and the pressure reducing pipe solves the blockage problem inside the conveying system in a simple way.

[0005] The technical solution adopted by the present invention is to provide a powder injection pile powder conveying device, including the tank body, the air circuit unit, the conveying pipeline, the feeding device, the mixer and the control unit, the tank body outlet is connected to the upper inlet of the feeding device, and the feeding device outlet is connected to the mixer inlet; the mixer outlet is connected to the conveying pipeline inlet, and at least one circumferentially distributed air inlet pipe is connected to the outer peripheral wall of the mixer; the air circuit unit includes a main air supply pipe and at least one air supply branch, the inlet of the main air supply pipe is connected to the air supply unit, and the outlet of the main air supply pipe is respectively connected to the air supply branch through each of the air supply branches. It is connected to each corresponding air inlet pipe, the outlet of the conveying pipeline is connected to the drilling rig unit, at least one of the air supply branches is connected to a pressure reducing exhaust pipe, and the pressure reducing exhaust pipe is provided with a pressure reducing valve for controlling the connection and disconnection between its inner cavity and the outside atmosphere; the curing agent powder in the tank body enters the interior of the mixer along the feeding device under the action of internal pressure, and enters the conveying pipeline under the action of high-pressure gas injection of several of the air supply branches; the lower end of the feeding device is also connected to a dredging air supply branch, one end of the dredging air supply branch is connected to the air supply unit or the main air supply pipe, and the other end is connected to the inner cavity of the feeding device.

[0006] Furthermore, the air circuit unit also includes a tank body boosting pipe, one end of the tank body boosting pipe is connected to the main air supply pipe or the air supply unit, and the other end is connected to the top of the tank body, and the tank body boosting pipe is connected to a boosting valve; the upper side wall of the tank body is also provided with a feed valve, a safety valve, a pressure gauge for opening and closing the feed port, and an exhaust valve for opening and closing the exhaust pipe, and the outlet end of the feeding device is connected to a feeding switch valve; the main air supply pipe is connected to a main air circuit valve for controlling the intake flow; the air supply unit, boosting valve, feed valve, exhaust valve, main air circuit valve, feeding switch valve, unblocking air circuit valve, air supply branch valve and pressure reducing valve are all uniformly coordinated and controlled by the control unit. In the above-mentioned improved structure, the pressure inside the tank is increased by pressurization so that the pressure inside the tank is always higher than the pressure inside the conveying pipeline by a certain value, and the curing agent can be fed into the feeding device at a stable speed, thereby ensuring uniform distribution of the material at each section of the pile body; the control unit can automatically control the opening and closing status of each switch valve at different time points through a program, thereby reducing manual operation and avoiding subjective reasons that may cause a decrease in construction quality.

[0007] As an improvement, the front of the feeder tapers gradually from top to bottom, with the bottom connected to a slotted connecting pipe. The sides of the feeder taper in a triangular shape, gradually decreasing in width from top to bottom. One end of the connecting pipe connects to the mixer inlet, and the other end is equipped with a removable plug. In this improved structure, the specially shaped feeder facilitates the smooth descent of the curing agent powder. Furthermore, the connection to the slotted connecting pipe at the bottom increases the curing agent transport cross-section, reducing the curing agent's compaction at this point and effectively preventing blockage.

[0008] In a further improvement, the mixer is cylindrical in shape, and the angle between each intake pipe and the mixer is less than 90°, and each intake pipe is inclined toward the side closest to the feeding device. In this improved structure, the intake pipe and the mixer are arranged at an acute angle, allowing high-pressure gas entering the mixer to smoothly enter the delivery pipeline, reducing transmission energy loss.

[0009] In a further improvement, each of the air inlet pipes is positioned at the same distance from the front end of the mixer and arranged symmetrically along the circumference, or is positioned at different distances from the front end of the mixer, with a certain spacing between the air inlet pipes and arranged symmetrically along the circumference. In the above-mentioned improved structure, when multiple air inlet pipes are symmetrically positioned to supply air, the airflow distribution can be more uniform, and the flow path of the curing agent powder is not turbulent; when multiple air inlet pipes are spaced axially and evenly arranged circumferentially, the multiple air flows can enter the conveying pipeline more smoothly, and the spacing between the air inlet pipes can gradually enhance the energy of the gas-solid mixing flow, reducing the occurrence of blockage.

[0010] In a further improvement, the axis direction of each of the air inlet pipes passes through the center of the mixer and is arranged symmetrically along the circumference of the mixer, or the axis direction of each air inlet pipe is eccentrically arranged at the same distance from the center of the mixer and is evenly distributed along the circumference. In the above-mentioned improved structure, the axes of multiple air inlet pipes pass through the center of the mixer and are symmetrically arranged. The combined force generated by each airflow after entering the conveying pipeline is maximized, which can ensure the conveying energy. When the multiple air inlet pipes are eccentrically symmetrical, the airflow forms a rotating airflow within the pipeline after entering the conveying pipeline. The structure of multiple air inlet pipes makes the rotating airflow at the mixer have greater energy and stronger material carrying capacity.

[0011] Another technical solution adopted by the present invention is to provide a powder injection pile construction system, including an air supply unit, a drilling unit and the aforementioned powder conveying device, the drilling unit including a stirring drill bit, a drill rod and a signal transmitter arranged on the drilling unit, the stirring drill bit is arranged with a pressure monitoring device, the pressure monitoring device includes a lateral pressure sensor and a vertical pressure sensor, and the lateral pressure sensor and the vertical pressure sensor use wired or wireless transmission means to transmit the detected pressure data in the soil from the signal transmitter to the control unit for processing and analysis.

[0012] Another technical solution adopted by the present invention is to provide a control method for a powder injection pile construction system, characterized in that it includes the following specific steps: S1. Before construction, first connect the powder injection pile air supply unit, powder conveying device and drilling unit through the main air supply pipe and conveying pipeline in sequence; S2. The loading operation is started by the control unit. At this time, the feeding switch valve and the tank boost valve at the rear end of the feeding device are automatically closed, the feed valve and the exhaust valve at the top of the tank are opened, and the curing agent is fed into the tank through the feed port. When the weight of the curing agent reaches the set value, the control unit automatically stops loading, closes the feed valve and the exhaust valve, and opens the tank boost valve. At this time, the loading program ends; S3. After the drilling unit moves to the construction pile position, adjust the verticality, and use the control unit to start the preparation for pile driving operation. At this time, the gas supply unit starts to provide high-pressure gas, which is pressurized into the tank through the tank booster pipe. The pressure P1 in the tank is monitored in real time using a pressure gauge; the main gas circuit valve opens to provide gas to the transmission pipeline for each gas supply branch. During the gas supply period, the gas supply branch valve opens and closes at the set frequency interval to ensure that the gas circuit reaches a stable state; S4. Start the drilling unit to start the piling operation. At this time, the drilling unit starts to drill downward. When the drill bit enters the formation, the pressure monitoring device installed on the mixing drill bit will monitor the lateral and vertical pressure inside the soil, and calculate a soil pressure P2 through the control unit. During the drilling process, P1 is adjusted in real time to always keep the difference ΔP between the tank pressure P1 and the soil pressure P2 at a constant value; S5. After the mixing drill bit enters the soil, the feed switch valve is opened, and the internal pressure P1 of the tank is used to stably feed the curing agent powder through the feeding device and the mixer to the delivery pipeline. The multiple air inlet pipes are used to regularly supply air to form a stable solid-gas mixed flow in the mixer. During the drilling process, the fixed difference ΔP between the internal pressure P1 of the tank and the internal pressure P2 of the soil and the stable drilling speed are used to ensure the uniformity of the curing agent injected into each section of the pile. S6. After the drilling rig unit drills and sprays powder to the designed base height, the feed switch valve is closed to stop feeding, and the main air valve is adjusted to reduce the air supply. After continuous stirring for 0.5 minutes, the drill is raised to the surface to complete the construction of a single powder injection pile. S7: The drilling unit moves to the next pile position, and steps S2 to S6 are repeated to construct the next pile.

[0013] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects: 1. Compared with the traditional structure, the air supply unit adds at least one air supply branch in addition to the main air supply pipe, and the air supply branch is directly connected to the mixer. By regularly opening and closing the valves of each air supply branch, the gas entering the mixer can form a smooth airflow, thereby mixing the curing agent powder and the high-pressure gas more evenly, which is conducive to the uniform spreading of the curing agent.

[0014] 2. A pressure reducing exhaust pipe is provided on at least one gas supply branch, and a pressure reducing valve is provided on the pressure reducing exhaust pipe. During the construction process, the change of underground pressure is irregular, which may cause powder to accumulate at the nozzle and cause the pressure inside the conveying pipeline to increase suddenly. At this time, the monitoring system can automatically identify this situation, close the feeding switch valve and each gas supply branch valve, and open the pressure reducing valve to release the pressure inside the conveying pipeline. After the pressure is reduced and the pipeline is unblocked, the feeding drilling can be carried out, thereby preventing the pipe from bursting due to excessive pressure in the pipeline caused by nozzle blockage during construction.

[0015] 3. The air passage at the bottom of the feeding device of the powder conveying device is opened and closed at intervals during construction, which prevents the curing agent powder at the feeding device from being squeezed and blocked during a long feeding process, and can keep the powder at this part loose, making the transportation smoother.

[0016] 4. The multiple air inlet pipes installed on the mixer in front of the conveying pipeline adopt a combination of equidistant, unequal distance, axial symmetry, eccentric symmetry, etc., and adopt different inclination angles to effectively utilize the conveying energy provided by the high-pressure gas, improve the conveying capacity of the curing agent powder, and form a stable gas-solid fluid in the conveying pipeline.

[0017] 5. The pressure monitoring device provided on the mixing drill bit of the present invention can monitor the pressure in the soil in real time. The pressure data is transmitted to the control unit, and the curing agent delivery amount is controlled by adjusting the pressure difference between the tank pressure and the soil pressure, thereby achieving the demand for stable material supply.

[0018] 6. The powder injection pile feeding device of the present invention is uniformly controlled by a control unit. The loading and feeding functions during construction are automatically controlled according to the construction sequence, which reduces manual operation and the occurrence of errors caused by human subjective factors. At the same time, it also saves labor costs and improves construction efficiency.

[0019] Other structures of the present invention will be described in detail in the following detailed description, and in part will become apparent from the description or understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the powder material conveying device for powder injection piles of the present invention; Figure 2 Schematic diagram of the structure of the gas circuit unit in the present invention; Figure 3 It is a side view of the feeding device structure in the present invention; Figure 4 This is a side view of the mixer structure of Example 1 of the present invention; Figure 5 This is a side view of the mixer structure of Example 2 of the present invention; Figure 6 This is a side view of the mixer structure of Example 3 of the present invention; Figure 7 This is a side view of the mixer structure of Example 4 of the present invention; Figure 8 This is a front view of the mixer structure of Example 1 of the present invention; Figure 9 This is a front view of the mixer structure of Example 4 of the present invention; Figure 10 This is a structural diagram of a drilling rig unit in the present invention; Figure 11 Schematic diagram of the drill bit structure of the present invention; Figure 12 This is a schematic diagram of the partial structure of a pressure monitoring device according to a first embodiment of the present invention; Figure 13 This is a cross-sectional view of a drill bit according to a fifth embodiment of the present invention; Figure 14 This is a structural diagram of a pressure monitoring device according to a fifth embodiment of the present invention; Figure 15 It is a structural schematic diagram of the powder injection pile construction system of the present invention.

[0021] As shown in the figure: 100, air supply unit; 200, powder conveying device; 300, drilling unit; 1, safety valve; 2, pressure gauge; 3, boost valve; 4, tank boost pipe; 5, feed port; 6, feed valve; 7, exhaust valve; 8, exhaust channel; 9, tank; 10, main air supply pipe; 11, main air valve; 12, conveying pipe; 13, feeding device; 14, mixer; 15, connecting pipe; 16, feeding switch valve; 17, plug; 18, air valve for dredging; 19, air supply branch; 20, air pipe for dredging; 21, air supply branch valve; 211, air supply branch valve 1; 212, Air supply branch valve two; 213, air supply branch valve three; 22, air supply branch; 221, air supply branch one; 222, air supply branch two; 223, air supply branch three; 23, air inlet pipe; 231, air inlet pipe one; 232, air inlet pipe two; 233, air inlet pipe three; 24, stirring drill bit; 25, drill rod; 251, outer drill rod; 252, inner drill rod; 26, signal transmitter; 27, bottom excavation blade; 28, pressure monitoring device; 281, protective casing; 282, lateral pressure sensor; 283, vertical pressure sensor; 29-pressure reducing valve; 30-pressure reducing exhaust pipe. DETAILED DESCRIPTION

[0022] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of the present application and are not intended to limit the scope of protection of the embodiments of the present application. Those skilled in the art may adjust them as needed to suit specific application scenarios.

[0023] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0024] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions.

[0025] Example 1: The following combination Figures 1 to 4 、 Figure 8 、 Figures 10-12 and Figure 15 The specific implementation of the first embodiment of the present invention is described in detail: As attached Figure 1As shown, the powder conveying device 200 of the present invention includes a tank body 9, an air path unit, a conveying pipeline 12, a feeding device 13, a dredging unit, a pressure reducing unit, a mixer 14 and a corresponding control unit. The tank body 9 is installed on a bracket, and a corresponding weighing sensor is provided on the bracket, which can monitor the weight change of the tank body 9 in real time to realize real-time monitoring of the use of the powder in the tank body 9. The discharge port at the bottom of the tank body 9 is connected to the feeding device 13. A dredging unit is provided in the vertical direction at the bottom of the feeding device 13. The dredging unit can vertically spray high-pressure gas into the feeding device 13. It is opened once every T seconds during the feeding process to prevent the curing agent from agglomerating for a long time and forming a compaction, thereby ensuring a stable conveying volume. The outlet of the feeding device 13 is connected in sequence with the conveying pipe 12 of the mixer 14, and the curing agent powder can be transported from the inside of the tank body 9 along the feeding device 13 and the mixer 14; the air path unit is provided with high-pressure gas by the air supply unit 100. Before entering the mixer 14, a main air supply pipe 10 is divided into an air supply branch 1 221 and an air supply branch 2 222, and is connected to the air inlet pipe 1 211 and the air inlet pipe 2 212 on the mixer 14, so that the high-pressure gas and the curing agent powder form a gas-solid mixture in the mixer 14, which is delivered to the drill nozzle position of the drilling unit 300 through the conveying pipe 12 and then stirred into piles.

[0026] As attached Figure 1 As shown, all operations of the powder conveying device 200 of the present invention are uniformly controlled and adjusted in real time by the control unit to ensure the stability of the curing agent powder delivery rate. The tank body 9 in the present invention is a high-pressure tank body. The side wall of the tank body 9 is equipped with a safety valve 1, a pressure gauge 2, a boost valve 3, a boost pipe 4, a feed port 5, a feed valve 6, an exhaust valve 7, and an exhaust pipe 8. The main air supply pipe 10 is also connected to the main air valve 11. The outlet end of the feeding device 13 is connected to the feeding switch valve 16. Each switch valve is uniformly monitored and coordinated by the control unit. After the drilling rig is in place, construction can be started with just one click. The background control unit will automatically open and close the switch valves during the loading phase. After the loading is completed, it will automatically open and close the switch valves during the construction. At the same time, during the construction process, the control unit will also adjust the pressure in the tank body 9 in real time by monitoring the delivery rate and the drilling speed to ensure the uniformity of the curing agent incorporation. During the construction process, the pressure value P1 inside the tank body 9 is read by the pressure gauge 2 and sent to the control unit.

[0027] As attached Figure 2 、 3 As shown, the front of the feeding device 13 is gradually narrowed from top to bottom, and the side cross-section is approximately triangular. The lower part is connected to the slotted connecting pipe 15 to ensure the flow area of ​​the curing agent powder. The rear end of the connecting pipe 15 is a detachable plug 17, which can be easily cleaned when the internal curing agent becomes damp and agglomerated. The front end is connected to the mixer 14, and a feeding switch valve 16 for controlling the discharge of the curing agent is provided at one end near the mixer 14.

[0028] As attached Figure 2 、 4 As shown in FIG8 , the mixer 14 is a cylindrical structure, and an air inlet pipe 1 231 and an air inlet pipe 2 232 are arranged on its side wall, which are connected to the air supply branch 1 221 and the air supply branch 2 222 respectively. The air supply branch valve 1 211 and the air supply branch valve 2 212 control the air supply opening and closing of the air supply branch 1 221 and the air supply branch 2 222 respectively. The air inlet pipe 1 231 and the air inlet pipe 2 232 are both 15 cm away from the left end of the mixer 14, and the angle between the two air inlet pipes 23 and the main pipeline of the mixer 14 is 45 degrees; Figure 4 It can be seen that the two air inlet pipes 23 are evenly and symmetrically arranged on both sides of the mixer 14, and the axis direction of the air inlet pipe 23 passes through the center of the mixer 14. The high-pressure gases discharged from the two air inlet pipes 23 merge to form a main airflow to transport the curing agent.

[0029] In this embodiment, at least one air supply branch 22 is connected to a pressure reducing exhaust pipe 30 and is provided with a pressure reducing valve 29. One end of the pressure reducing exhaust pipe 30 is arranged at the air outlet end of the air supply branch valve 21, and the other end is opened and closed by the pressure reducing valve 29 and is connected to the atmosphere, so as to facilitate exhaust and pressure reduction when the internal pressure of the conveying pipeline is too high.

[0030] In some other embodiments, each air supply branch 22 may be connected to a pressure reducing exhaust pipe 30 and provided with a pressure reducing valve 29 to facilitate the selection of opening one or more pressure reducing valves 29 during use.

[0031] As attached Figure 2 As shown, the control unit programs the air supply branch valve 1 211 and the air supply branch valve 2 212 so that the air supply branch valve 1 211 is opened for 3 seconds and the air supply branch valve 2 212 is closed for 3 seconds. Then, the air supply branch valve 1 211 is closed for 3 seconds and the air supply branch valve 2 212 is opened for 3 seconds. Then, the air supply branch valve 1 211 and the air supply branch valve 2 212 are opened for 5 seconds simultaneously. This cycle is repeated during the construction process. This setting allows the curing agent powder and the high-pressure gas to be fully mixed in the mixer 14, forming a stable gas-solid mixed flow and is less likely to cause pipeline blockage.

[0032] like Figures 10-12The powder injection pile construction system of the present invention includes an air supply unit 100, a drilling unit 300 and a powder conveying device 200. In this embodiment, a multi-layer shearing mixing drill bit is used. The inside of the drill bit adopts a single-channel structure with only one main gas-powder channel 291. A pressure monitoring device 28 is hidden under the excavation blade 27 at the bottom of the mixing drill bit 24. There are two groups of pressure monitoring devices 28 symmetrically arranged along the diameter of the mixing drill bit 25. Each group of pressure monitoring devices 28 consists of a protective sleeve 281, a lateral pressure sensor 282 and a vertical pressure sensor 283. The pressure surfaces of the two types of sensors are exposed in the protective sleeve in the corresponding direction. At the pipe opening, two vertical pressure sensors 283 in this embodiment are arranged on one side. The pressure data measured by the lateral pressure sensor 282 and the vertical pressure sensor 283 are provided as electrical signals through the built-in micro power supply. The drill pipe 25 and the earth are used as carriers to transmit the pressure data to the signal transmitter 26, which is then wirelessly transmitted to the control unit by the signal transmitter 26. In the control unit, multiple pressure data are integrated and processed into soil pressures P2 at different depths. During the drilling process, the control unit adjusts P1 in real time to always keep the difference △P between the tank pressure P1 and the soil pressure P2 at a constant value of 0.2 MPa.

[0033] The control method of the powder injection pile construction system in this embodiment includes the following steps: S1. Before construction, first connect the powder injection pile air supply unit 100, the powder conveying device 200 and the drilling unit 300 in sequence through the main air supply pipe 10 and the conveying pipe 12; S2. The loading operation is started by the control unit. At this time, the feeding switch valve 16 at the rear end of the feeding device 13 and the tank body pressurization valve 3 are automatically closed, the feeding valve 6 and the exhaust valve 7 at the top of the tank body 9 are opened, and the curing agent is fed into the tank body 9 through the feeding port 5. When the weight of the curing agent reaches the set value, the control unit automatically stops loading, closes the feeding valve 6 and the exhaust valve 7, and opens the tank body pressurization valve 3. At this time, the loading program ends; S3. After the drilling unit 300 moves to the construction pile position, it adjusts the verticality and uses the control unit to start preparing for the pile driving operation. At this time, the gas supply unit 100 starts to supply high-pressure gas, which is pressurized into the tank body 9 through the tank body pressurization pipe 4. The pressure P1 in the tank body 9 is monitored in real time by the pressure gauge 2. The main gas circuit valve 11 is opened to provide gas to the delivery pipe 12 for each gas supply branch 22. During the gas supply period, the gas supply branch valve 21 is opened and closed at a set frequency interval to ensure that the gas circuit reaches a stable state. S4. The drilling unit 300 is started to start the piling operation. At this time, the drilling unit 300 begins to drill downward. When the drill bit enters the formation, the pressure monitoring device 28 installed on the mixing drill bit 24 monitors the lateral and vertical pressures inside the soil, and calculates and synthesizes a soil pressure P2. During the drilling process, P1 is adjusted in real time to always maintain the difference ΔP between the tank pressure P1 and the soil pressure P2 at a constant value; S5. After the mixing drill bit enters the soil, the feed switch valve 16 is opened, and the internal pressure P1 of the tank body 9 is used to stably feed the curing agent powder through the feeding device 13 and the mixer 14 to the delivery pipe 12. The multiple air inlet pipes 23 are used to regularly supply air at intervals to form a stable solid-gas mixed flow in the mixer 14. During the drilling process, the fixed difference ΔP between the tank pressure P1 and the soil pressure P2 and the stable drilling speed are used to ensure the uniformity of the curing agent injected into each section of the pile body. S6. After the drilling unit 300 drills and sprays powder to the designed base height, the feed switch valve 16 is closed to stop feeding, and the main air valve 11 is adjusted to reduce the air supply. After stirring for 0.5 minutes, the drill is raised to the surface to complete the construction of a single powder injection pile. S7: The drilling unit 300 moves to the next pile position and repeats steps S2 to S6 to perform the next pile construction.

[0034] Example 2: The following combination Figures 1-3 、 Figure 5 、 10 ~12 and Figure 15 The specific implementation of the first embodiment of the present invention is described in detail: The basic structure of the backend device in this embodiment is similar to that in the first embodiment, except that: like Figure 5As shown, in this embodiment, the mixer 14 is provided with an air inlet pipe 1 231, an air inlet pipe 232 and an air inlet pipe 3 233, which are respectively connected to the air supply branch 1 221, the air supply branch 2 222 and the air supply branch 3 223. The air inlet pipe 1 231, the air inlet pipe 232 and the air inlet pipe 3 233 are all 10 cm away from the left end of the mixer 14. The angle between the air inlet pipe 23 and the main pipeline of the mixer 14 is 35 degrees. The three air inlet pipes are evenly and symmetrically arranged on the circumferential side of the mixer 17, and the axial direction of the air inlet pipe 21 passes through the center of the mixer 17. The high-pressure gases discharged from the three groups of air inlet pipes merge to form a main airflow to transport the curing agent; the control unit is used to The air supply branch valve 1 211, the air supply branch valve 2 212 and the air supply branch valve 3 213 are programmed so that the air supply branch valve 1 211 and the air supply branch valve 2 212 are opened for 5 seconds while the air supply branch valve 3 213 is closed for 5 seconds, and then the air supply branch valve 1 211 and the air supply branch valve 2 212 are closed for 5 seconds while the air supply branch valve 3 213 is opened for 5 seconds, and then the air supply branch valve 1 211, the air supply branch valve 2 212 and the air supply branch valve 3 213 are opened at the same time for 5 seconds, and the cycle is performed during the construction process. The three air inlet pipes are arranged symmetrically so that the resultant force generated after each air flow enters the transmission pipeline is maximized, thereby ensuring the transmission energy.

[0035] In this embodiment, the mixing drill bit 24 uses three bottom excavation blades 27, and there are three sets of corresponding pressure monitoring devices 28 symmetrically arranged under the bottom excavation blades 27. During the drilling process, the difference ΔP between the pressure P2 in the treated soil and the pressure P1 in the tank is always maintained at a constant value of 0.3 MPa.

[0036] The operation method in this embodiment is the same as that in the first embodiment and will not be described in detail.

[0037] Example 3: The basic structure of the backend device in this embodiment is similar to that in the first embodiment, except that: like Figure 6As shown, the mixer 14 in this embodiment is provided with an air inlet pipe 1 231 and an air inlet pipe 2 232, which are respectively connected to the air supply branch 1 221 and the air supply branch 2 222. The air inlet pipe 1 231 and the air inlet pipe 2 232 are both 20 cm away from the left end of the mixer 14. The angle between the air inlet pipe 23 and the main pipeline of the mixer 14 is 25 degrees. The two air inlet pipes are eccentrically symmetrical in the cross section of the pipeline. The axial direction of each air inlet pipe 23 has the same eccentricity with the center of the mixer 14. The high-pressure gases discharged from the two groups of air inlet pipes converge to form a main airflow to transport the curing agent. Since the two air inlet pipes 23 are eccentrically symmetrical, the two air flows will form a rotating airflow after entering the interior of the mixer 14. This structure makes the rotating airflow at the mixer have greater energy and stronger material carrying capacity. The control unit programs the gas supply branch valve 1 211 and the gas supply branch valve 2 212 so that the opening time of the gas supply branch valve 1 211 and the gas supply branch valve 2 212 is 6 seconds and the closing time is 2 seconds each time. When the gas supply starts, the gas supply branch valve 1 211 is opened for 2 seconds, and then the gas supply branch valve 2 212 is opened again, and the process is repeated in sequence to always keep gas flowing in the delivery pipeline.

[0038] In this embodiment, the mixing drill bit 24 adopts unidirectional mixing, and there are two bottom excavation blades 27. There are two sets of corresponding pressure monitoring devices 28 symmetrically arranged under the bottom excavation blades 27, and each set of pressure monitoring devices 28 is provided with a vertical pressure sensor 283 and a lateral pressure sensor 282 at the bottom. During the drilling process, the difference ΔP between the pressure P2 in the treated soil and the pressure P1 in the tank is always maintained at a constant value of 0.1 MPa, and P1 is adjusted accordingly in real time during the drilling process.

[0039] The operation method in this embodiment is the same as that in the first embodiment and will not be described in detail.

[0040] Example 4: The basic structure of the backend device in this embodiment is similar to that in the second embodiment, except that: like Figure 7 、 Figure 9As shown, the mixer 14 in this embodiment is provided with three groups of air inlet pipes 23 and are respectively connected to the air supply branch 22, air inlet pipe 1 231 is 5 cm away from the left end of the mixer 14, air inlet pipe 232 is 15 cm away from the left end of the mixer 14, and air inlet pipe 3 233 is 25 cm away from the left end of the mixer 17, and the angle between each air inlet pipe 23 and the main pipeline of the mixer 14 is 30 degrees. The three air inlet pipes 23 are eccentrically symmetrical in the cross section of the pipeline, and the axial direction of each air inlet pipe 23 has the same eccentricity with the center of the mixer 14. The high-pressure gases discharged from the three groups of air inlet pipes 23 converge to form a main airflow to transport the curing agent; the mixer in this embodiment not only has more groups of air inlet pipes 23, but also is eccentrically symmetrical, with a certain distance between them, so that the resistance encountered by the high-pressure gas entering the mixer 14 is smaller, and a step-by-step acceleration effect is produced, forming a rotating airflow that is more conducive to the transportation of the curing agent. The air supply branch valve 1 211, the air supply branch valve 2 212 and the air supply branch valve 3 213 are programmed through the control unit so that the opening time of the air supply branch valve 1 211, the air supply branch valve 2 212 and the air supply branch valve 3 213 is 8 seconds and the closing time is 4 seconds each time. When the air supply starts, the air supply branch valve 1 211 is opened for 4 seconds, and then the air supply branch valve 2 212 is opened again. After the air supply branch valve 2 212 is opened for 4 seconds, the air supply branch valve 3 213 is opened again, and the process is repeated in sequence to always keep gas flowing in the delivery pipeline.

[0041] In this embodiment, the mixing drill bit 24 adopts unidirectional mixing, and there are three bottom excavation blades 27. There are three sets of corresponding pressure monitoring devices 28 symmetrically arranged under the bottom excavation blades 27, and three vertical pressure sensors 283 and one lateral pressure sensor 282 are provided at the bottom of each set of pressure monitoring devices 28. During the drilling process, the difference ΔP between the pressure P2 in the treated soil and the pressure P1 in the tank is always maintained at a constant value of 0.35 MPa, and P1 is adjusted accordingly in real time during the drilling process.

[0042] The operation method in this embodiment is the same as that in the second embodiment and will not be described in detail.

[0043] Example 5 The basic structure and control method of the background device in this embodiment are similar to those in the first embodiment, except that: like Figure 13 As shown, the drill bit 24 in this embodiment adopts a multi-layer shearing and mixing drill bit, which is respectively provided with a gas-powder channel 291 and an auxiliary gas channel 292. The gas-powder channel 291 carries the curing agent powder through high-pressure gas, and the auxiliary gas channel 292 separately transports high-pressure gas, and the auxiliary jet sprays the curing agent into the soil to prevent the curing agent from being unable to be sprayed out smoothly due to insufficient pressure or blockage.

[0044] like Figure 14As shown, the pressure monitoring device 28 is set on the side of the drill pipe 25 above the tunneling blade 27 and is arranged in a circularly symmetrical manner, wherein the vertical pressure sensor 283 and the lateral pressure sensor 282 are arranged at two intervals respectively. During the drilling process, the difference △P between the processed soil pressure P2 and the tank pressure P1 is always maintained at a constant value of 0.15MPa, and P1 is adjusted accordingly in real time during the drilling process.

[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A powder material conveying device for powder injection piles, characterized by: The invention comprises a tank body (9), an air circuit unit, a conveying pipeline (12), a feeding device (13), a mixer (14) and a control unit, wherein the outlet of the tank body (9) is connected to the upper inlet of the feeding device (13), and the outlet of the feeding device (13) is connected to the inlet of the mixer (14); the outlet of the mixer (14) is connected to the inlet of the conveying pipeline (12), and at least one air inlet pipe (23) distributed along the circumferential direction is connected to the outer peripheral wall of the mixer (14); the air circuit unit comprises a main air supply pipe (10) and at least one air supply branch (22), the inlet of the main air supply pipe (10) is connected to the air supply unit (100), and the outlet of the main air supply pipe (10) is connected to each corresponding air inlet pipe (23) through each air supply branch (22). The outlet of the delivery pipeline (12) is connected to the drilling unit (300), at least one of the air supply branches (22) is connected to a pressure reducing exhaust pipe (30), and the pressure reducing exhaust pipe (30) is provided with a pressure reducing valve (29) for controlling the opening and closing of the inner cavity thereof and the outside atmosphere; the curing agent powder in the tank body (9) enters the interior of the mixer (14) along the feeding device (13) under the action of the internal pressure, and enters the delivery pipeline (12) under the action of the high-pressure gas jet from the plurality of air supply branches (22); the lower end of the feeding device (13) is further connected to a dredging air supply branch (19), one end of the dredging air supply branch (19) is connected to the air supply unit (100) or the main air supply pipe, and the other end is connected to the inner cavity of the feeding device (13).

2. The powder material conveying device for powder injection pile according to claim 1, characterized in that: The gas circuit unit further comprises a tank body boosting pipe (4), one end of which is connected to the main gas supply pipe (10) or the gas supply unit (100), and the other end of which is connected to the top of the tank body (9), and a boosting valve (3) is connected to the tank body boosting pipe (4); a feed valve (6) for opening and closing the feed port (5), a safety valve (1), a pressure gauge (2) and a valve for opening and closing the exhaust pipe (8) are also provided on the upper side wall of the tank body (9). The exhaust valve (7) is connected to the outlet end of the feeding device (13) and is connected to a feeding switch valve (16); the main air path valve (11) for controlling the intake air flow is connected to the main air supply pipe (10); the air supply unit, the boost valve (3), the feed valve (6), the exhaust valve (7), the main air path valve (11), the feeding switch valve (16), the dredging air path valve (18), the air supply branch valve (21) and the pressure reducing valve (29) are all controlled by the control unit in a unified and coordinated manner.

3. The powder material conveying device for powder injection pile according to claim 1, characterized in that: The front of the feeding device (13) is gradually narrowed from top to bottom, and the bottom is connected to the upper slotted connecting pipe (15). The side of the feeding device (13) is triangular in shape with gradually decreasing width from top to bottom. One end of the connecting pipe (15) is connected to the inlet of the mixer (14), and the other end is provided with a detachable plug (17).

4. The powder material conveying device for powder injection pile according to any one of claims 1 to 3, characterized in that: The mixer (14) is a cylindrical structure, the connection angle between each air inlet pipe (23) and the mixer (14) is less than 90°, and each air inlet pipe (23) is inclined toward a side close to the feeding device (13).

5. The powder material conveying device for powder injection pile according to claim 4, characterized in that: Each of the air inlet pipes (23) is arranged at the same distance from the front end of the mixer (14) and is symmetrically arranged along the circumference, or is arranged at different distances from the front end of the mixer (14), and there is a certain distance between the air inlet pipes (23) and they are symmetrically arranged along the circumference.

6. The powder material conveying device for powder injection pile according to claim 5, characterized in that: The axial direction of each of the air inlet pipes (23) passes through the center of the mixer (14), and the air inlet pipes (23) are arranged in a symmetrical manner along the circumferential side of the mixer (14).

7. The powder material conveying device for powder injection pile according to claim 5, characterized in that: The axial direction of each of the air inlet pipes (23) is eccentrically arranged at the same distance from the center of the mixer (14), and is evenly distributed along the circumferential direction of the mixer (14).

8. A powder injection pile construction system, characterized by: The invention comprises an air supply unit (100), a drilling unit (300) and a powder conveying device (200) according to any one of claims 1 to 7, wherein the drilling unit (300) comprises a stirring drill bit (24), a drill rod (25) and a signal transmitter (26) arranged on the drilling unit, and a pressure monitoring device (28) is arranged on the stirring drill bit (24), and the pressure monitoring device (28) comprises a lateral pressure sensor (282) and a vertical pressure sensor (283), and the lateral pressure sensor (282) and the vertical pressure sensor (283) use wired or wireless transmission means to transmit the pressure data in the soil detected by the signal transmitter (26) to the control unit for processing and analysis.

9. A control method for the powder injection pile construction system according to claim 8, characterized in that: The specific steps include: S1. Before construction, the powder injection pile air supply unit (100), the powder conveying device and the drilling unit (300) are connected in sequence through the main air supply pipe (10) and the conveying pipe (12); S2, the feeding operation is started by the control unit. At this time, the feeding switch valve (16) at the rear end of the feeding device (13) and the tank body pressure boosting valve (3) are automatically closed, the feeding valve (6) and the exhaust valve (7) at the top of the tank body (9) are opened, and the curing agent is fed into the tank body (9) through the feeding port (5). When the weight of the curing agent reaches the set value, the control unit automatically stops feeding, closes the feeding valve (6) and the exhaust valve (7), and opens the pressure boosting valve (3). At this time, the feeding program ends; S3. After the drilling unit (300) moves to the construction pile position, the verticality is adjusted and the control unit is turned on to prepare for the pile driving operation. At this time, the gas supply unit (100) starts to provide high-pressure gas, and pressurizes the tank body (9) through the tank body pressurization pipe (4). The pressure P1 in the tank body (9) is monitored in real time by the pressure gauge (2); the main gas circuit valve (11) is opened to provide the gas supply branch (22) with the delivery pipe (12). During the gas supply period, the gas supply branch valve (21) is opened and closed at a set frequency interval to make the gas circuit reach a stable state; S4, start the drilling unit (300) to start the piling operation, at which time the drilling unit (300) starts to drill downward, and when the drill bit enters the stratum, the pressure monitoring device (28) installed on the mixing drill bit (24) monitors the lateral and vertical pressures inside the soil, and calculates a soil pressure P2 through the control unit, and adjusts P1 in real time during the drilling process, so as to always keep the difference ΔP between the tank pressure P1 and the soil pressure P2 at a constant value; S5. After the mixing drill bit enters the soil, the feed switch valve (16) is opened, and the internal pressure P1 of the tank body (9) is used to stably feed the curing agent powder through the feeding device (13) and the mixer (14) to the delivery pipe (12), and the plurality of air inlet pipes (23) are used to regularly supply air at intervals to form a stable solid-gas mixed flow in the mixer (14). During the drilling process, the fixed difference ΔP between the tank pressure P1 and the soil pressure P2 and the stable drilling speed are used to ensure the uniformity of the curing agent injected into each section of the pile body; S6. After the drilling unit (300) drills down and sprays powder to the designed bottom height, the feed switch valve (16) is closed to stop feeding, and the main air valve (11) is adjusted down to reduce the air supply. After stirring for 0.5 minutes, the drill is raised to the surface to complete the construction of a single powder injection pile. S7, the drilling unit (300) moves to the next pile position, and repeats steps S2 to S6 to construct the next pile.

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