Intelligent grouting prestressed pipe pile for eicp or micp reinforcement

Abstract

The application provides an intelligent grouting prestressed pipe pile for EICP or MICP reinforcement, the pipe pile comprising a pipe pile body, a vertical grouting pipe, a drainage cleaning pipe and a movable piston; the pipe pile side wall is provided with an electrically-controlled flap valve assembly, a wireless calcium ion monitor and a transverse spout of a filter screen. The movable piston has a grouting and negative pressure suction dual function through position switching: when reinforcing, the internal negative pressure formed by the piston movement forms a hydraulic gradient to induce the directional diffusion of the biological slurry between piles; at the same time, the embedded stress strain gauge feeds back the side friction resistance change to accurately determine the reinforcement range, and the wireless calcium ion monitor monitors the biochemical reaction process in real time. The pile tip is provided with a U-shaped pipe to form a cleaning loop, and the pipe sealing butt joint is realized in cooperation with a special-shaped end plate. The application realizes the intelligentization and precision of biological foundation reinforcement, significantly improves the reinforcement efficiency and uniformity, and effectively prevents the pipe mineralization blockage.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering biological reinforcement technology, and in particular to an intelligent grouting prestressed pipe pile for EICP or MICP reinforcement. Background Technology

[0002] Traditional prestressed concrete pipe piles, after construction, have side friction resistance primarily dependent on the properties of the surrounding soil, making subsequent reinforcement difficult. Existing grouting piles mostly rely on manual grouting, which suffers from problems such as inaccurate grouting location, inability to precisely control pressure, and unknown reinforcement range. Furthermore, when multiple piles are reinforced together, the lack of effective means to guide the diffusion of the reinforcing fluid leads to uneven grouting, affecting the foundation reinforcement effect and causing material waste.

[0003] Microbial-induced calcium carbonate (MICP) technology utilizes urease produced by the metabolism of microorganisms (such as Bacillus pasteurellii), while enzyme-induced calcium carbonate (EICP) technology directly utilizes free urease extracted from plants. Both utilize urease to catalyze the hydrolysis of urea to generate carbonate ions, which then react with a calcium source to form calcium carbonate crystals with cementing properties, thereby achieving cementation and reinforcement of soil particles. Although MICP and EICP cementing solutions, i.e., reinforcement solutions, have significant advantages such as low slurry viscosity and high ground permeability, they still face significant challenges in pipe pile engineering applications: the cementing solution is easily lost due to groundwater flow interference, and the biomineralization process in deep geology is in a "black box" state, resulting in poor uniformity and reliability of reinforcement.

[0004] Therefore, existing technologies still lack an intelligent grouting prestressed pipe pile that can effectively improve the uniformity and efficiency of EICP and MICP grouting reinforcement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention integrates biomineralization technology into precast pipe piles. Utilizing a built-in calcium ion monitoring and strain feedback system, it achieves real-time tracking of the biochemical reaction process. Combined with the negative pressure induction mechanism generated by active temperature control within the pile and the linkage between injection and drainage, it effectively solves the problems of random migration and disordered loss of bio-slurry in groundwater environments. This overcomes the technical limitations of unclear biochemical reaction states and uneven cementation in deep strata, significantly improving the controllability and strength of the soil reinforcement around the pile.

[0006] This invention provides an intelligent grouting prestressed pipe pile for EICP or MICP reinforcement, comprising the following technical solutions:

[0007] This invention provides an intelligent grouting prestressed pipe pile for EICP or MICP reinforcement, comprising:

[0008] Pipe pile (1), wherein a vertical pipeline system is provided inside the pipe pile (1);

[0009] The vertical piping system includes vertically parallel grouting pipes (2), drainage and cleaning pipes (3), and a U-shaped pipe (15) located inside the pile tip (14) for connecting the vertical grouting pipes (2) and the drainage and cleaning pipes (3).

[0010] The movable piston (4) is installed inside the vertical grouting pipe (2) and can move vertically inside the vertical grouting pipe (2). It can block the vertical grouting pipe (2) at its stopping position to assist in switching between grouting mode and drainage mode.

[0011] Multiple horizontal nozzles (5) are located at different heights of the vertical grouting pipe (2) and connect the vertical grouting pipe (2) to the soil outside the pile;

[0012] The central control system includes a central control unit (13), an electric gate valve assembly (6), and a wireless calcium ion concentration monitor (7).

[0013] The central control unit (13) is located on the upper part of the prestressed pipe pile and includes a water pump jet suction device and a pressure controller. The water pump jet suction device can change the internal pressure in the pipes below the position of the movable piston (4) in the U-shaped pipe (15), the drainage cleaning pipe (3) and the vertical grouting pipe (2), thereby cooperating with the movable piston (4) to switch the grouting mode and the drainage mode of the pipe pile (1).

[0014] The electrically controlled gate valve assembly (6) is used to control the opening and closing of the transverse nozzle (5);

[0015] The wireless calcium ion concentration monitor (7) is located inside the transverse nozzle (5). In grouting mode, it monitors the calcium ion concentration in the cementing fluid injected into the soil by the prestressed pipe pile. In drainage mode, it monitors the calcium ion concentration in the cementing fluid of the soil flowing into the transverse nozzle (5) from the soil. It is used to determine the degree of movement and diffusion of the cementing fluid and the degree of cementation.

[0016] Preferably, the movable piston (4) is connected to the central control unit (13) via a traction rope (401);

[0017] In the drainage mode, the movable piston (4) moves to the horizontal nozzle (5) above the target depth and opens the horizontal nozzle (5) below the movable piston (4). The water pump jet suction device in the central control unit (13) forms a negative pressure liquid suction channel in the pipe space below the movable piston (4) in the drainage cleaning pipe (3), U-shaped pipe (15) and vertical grouting pipe (2). The hydraulic gradient guides the cementing liquid injected into the soil layer by the other prestressed pipe piles to flow towards the prestressed pipe pile, so as to improve the uniformity of EICP or MICP reinforcement at different distances of the prestressed pipe piles.

[0018] In grouting mode, the movable piston (4) moves to the horizontal nozzle (5) below the target reinforced soil layer depth. The central control unit (13) activates the internal heating device to preheat the cementing liquid to the preset reaction temperature and adjusts the grouting pressure through the pressure controller in the central control unit (13) to press the cementing liquid into the soil layer through the vertical grouting pipe (2) from the target horizontal nozzle (5).

[0019] Preferably, the transverse nozzle (5) is arranged inclined upwards and outwards from the prestressed pipe pile;

[0020] The transverse nozzle (5) is provided with an electrically controlled gate valve assembly (6), a wireless calcium ion concentration monitor (7), and a reverse filter (8) in sequence facing the soil layer.

[0021] Preferably, a vertically distributed frame (25) is provided inside the pipe pile (1), a sensing sealing chamber (123) is provided on the frame (25), and a self-compensating sensing unit is provided inside the sensing sealing chamber (123). The self-compensating sensing unit includes a suspended compensation block (122) adhered to the soft silicone or polymer sponge (26) on the inner wall of the sealing chamber (123), a stress strain gauge (12) attached to the frame (25), and a temperature compensation plate (121) attached to the surface of the suspended compensation block (122).

[0022] The temperature compensation plate (121) can compensate for temperature changes at different underground depths, as well as temperature changes caused by heat conduction due to the flow of the cementitious liquid after heating;

[0023] The suspension compensation block (122) is made of the same material as the frame and is in a state of independent force from the frame (25);

[0024] The stress strain gauge (12) and the temperature compensation gauge (121) are connected to the compensation circuit of the central control unit (13) to counteract thermal interference; the stress strain gauge (12) feeds back data to obtain the distribution of side friction resistance and determines the location of the weak interlayer; the central control unit (13) calculates the real-time side friction resistance of the prestressed pipe pile according to the axial stress gradient and determines the soil reinforcement range and effect accordingly.

[0025] Preferably, the vertical grouting pipe (2), drainage and cleaning pipe (3), and U-shaped pipe (15) form a cleaning circulation loop, which can clean the residual EICP or MICP cementing liquid and its products in the pipeline after grouting is completed.

[0026] Preferably, the central control unit (13) also integrates a temperature sensor, a flow rate sensor, a drive motor and a heating device to adjust the reaction environment of the EICP or MICP cementing liquid and participate in the realization of the grouting mode and the drainage mode.

[0027] Preferably, each of the electrically controlled gate valve assemblies (6) used to control the switching of the transverse nozzle (5) is integrated into a sealed protective shell (22); the sealed protective shell (22) is provided with a micro drive assembly, including a micro motor (16), a return spring (18), a mechanical linkage structure (17), and a sealing plate (21) connected in sequence; the mechanical linkage structure (17) includes a longitudinal lead screw (19), a transmission nut (23), and a connecting rod (24), the longitudinal lead screw (19) is connected to the micro motor (16), the return spring (18) and the transmission nut (23) are sleeved on the longitudinal lead screw (19), and the transmission nut (23) is rigidly connected to the sealing plate (21) through the connecting rod (24);

[0028] When powered on, the micro motor (16) can drive the mechanical linkage structure (17) to move the sealing plate (21) to open the transverse nozzle (5); when powered off, the reset spring (18) can drive the sealing plate (21) to reset to block the transverse nozzle (5).

[0029] Preferably, the prestressed pipe pile is made up of multiple pipe piles (1) connected longitudinally by irregular end plates (9). One side of the irregular end plate (9) is a concave ring with an annular groove and the other side is a convex ring with a protruding ring. Both the concave ring and the convex ring are provided with through holes corresponding to the vertical grouting pipe (2). The convex-concave fit between the irregular end plates (9) ensures the sealing connection of the grout channel.

[0030] Each section of the pipe pile (1) is provided with a special-shaped end plate (9) at the upper and lower ends respectively. The concave ring of the special-shaped end plate (9) at the upper end of the pipe pile (1) faces upward and a connecting pipe section (11) protruding from the end face is provided in the through hole. The convex ring of the special-shaped end plate (9) at the lower end of the pipe pile (1) faces downward and a water-stop rubber sleeve (10) is provided in the through hole.

[0031] The present invention also provides a construction method for prestressed pipe piles, comprising:

[0032] Step 1: Install prestressed concrete pipe piles;

[0033] Step 2: The wireless calcium ion concentration monitor (7) collects the initial chemical background value of the calcium ion concentration in the soil layer, and the stress strain gauge (12) collects the original strain signal; the central control unit (13) obtains the background data of the initial axial force and side friction of the pile body through the differential bridge of the temperature compensation plate (121) and the stress strain gauge (12) and the built-in algorithm, monitors the side friction distribution of each section, and determines the location of the weak soil layer with missing side friction by the change of axial force gradient between adjacent sections, and sets it as the target reinforcement range;

[0034] Step 3: The movable piston (4) inside the command pile moves to the horizontal nozzle (5) below the target reinforcement layer to execute the grouting mode. The central control unit (13) starts the internal heating device to preheat the cementing liquid to the preset reaction temperature, and adjusts the grouting pressure through the pressure controller in the central control unit (13). The cementing liquid used for soil reinforcement is pressed into the soil layer from the horizontal nozzle (5) of the target through the vertical grouting pipe (2).

[0035] Step 4: When the adjacent prestressed pipe pile is grouting, the movable piston (4) of this prestressed pipe pile is moved to the horizontal nozzle (5) above the grouting reinforcement soil layer depth to execute the diversion mode. The central control unit (13) opens the horizontal nozzle (5) below the movable piston (4) and opens the water pump jet suction device in the central control unit (13) to form a negative pressure in the vertical grouting pipe (2), U-shaped pipe (15) and drainage cleaning pipe (3), inducing the cementing liquid injected into the soil layer by the adjacent pipe pile to diffuse towards this pile. When the cementing liquid in the reinforcement soil layer flows into the inclined horizontal nozzle (5) of the adjacent pipe pile, and the calcium ion concentration value measured by the wireless calcium ion concentration monitor (7) in the horizontal nozzle (5) is close to the calcium ion concentration of the grouting pile nozzle, the horizontal nozzle (5) is closed.

[0036] Step 5: When the change in calcium ion concentration value monitored by the wireless calcium ion concentration monitor (7) tends to be stable, alternate between grouting mode and drainage mode, and repeat the above steps 3 to 4. When the side friction resistance monitored in real time reaches the design threshold and the calcium ion concentration drops back to the background value, the reinforcement operation is completed.

[0037] After the reinforcement work is completed, open the bottom horizontal nozzle (5), start the water pump jet suction device to generate negative pressure, and suck the remaining cementing liquid waste in the soil around the pile into the pipe space below the movable piston (4) in the drainage cleaning pipe (3), U-shaped pipe (15) and vertical grouting pipe (2), and then suck it into the central control unit (13) for harmless treatment before discharge.

[0038] The present invention also provides a construction method for intelligent grouting prestressed pipe piles for EICP or MICP reinforcement.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] (1) This invention integrates a calcium ion monitor and a stress strain gauge at the nozzle to capture the biochemical reaction process of EICP or MICP and the dynamic changes in soil side friction in real time. At the same time, it integrates a temperature sensor and a heating device to adjust the optimal temperature range for urease activity in the EICP or MICP reaction in real time.

[0041] (2) The movable piston, vertical pipeline system, water pump jet suction device and pressure controller of the present invention are linked together in the soil between piles to establish an active "injection-suction" hydraulic gradient. By inducing slurry directional infiltration through negative pressure, the slurry is forced to uniformly penetrate the soil layer between piles, effectively avoiding slurry loss and local blockage, and ensuring the homogeneity of large-area foundation reinforcement.

[0042] (3) Based on the monitored side friction distribution, the present invention can flexibly switch the target nozzle to reinforce the weak interlayer at a specific depth, which greatly saves the amount of EICP or MICP binder and achieves the optimal configuration of reinforcement performance.

[0043] This invention utilizes a central control unit to coordinate the positive pressure of grouting piles with the negative pressure of diversion piles, creating an active "injection-absorption" hydraulic gradient in the soil between piles. Compared to traditional methods relying on gravity or single grouting pressure diffusion, this invention significantly extends the effective directional migration distance of the cementing fluid by leveraging the centripetal hydraulic gradient generated by negative pressure. Experimental data shows that in conventional sandy soils, this invention can increase the effective drainage radius of the cementing fluid from the traditional 1.0m to over 3.0m. This not only ensures the homogeneity of the soil reinforcement between piles but also allows for a larger pile spacing layout, thereby reducing the number of pipe piles required for the same reinforcement area by 20%-30%, lowering material costs, and shortening the construction period. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of the pipe pile of the present invention;

[0045] Figure 2 This is a schematic diagram of the irregularly shaped end plate and the pipe connection structure. Figure 2 (a) is a schematic diagram of the pipeline connection structure. Figure 2 (b) is a schematic diagram of the irregular end plate;

[0046] Figure 3 This is a schematic diagram of a horizontal nozzle structure;

[0047] Figure 4 This is a schematic diagram of the micro-drive component structure. Figure 4 (a) is a schematic diagram of the overall appearance. Figure 4 (b) is a schematic diagram of the internal structure;

[0048] Figure 5 This is a schematic diagram of the sensor sealing chamber assembly structure;

[0049] Figure 6 This is a schematic diagram of the grouting and drainage process for pipe piles. Figure 6 (a) is the grouting mode. Figure 6 (b) is the traffic generation mode;

[0050] Figure 7This is a schematic diagram of the functional modules.

[0051] In the diagram: 1. Pipe pile, 2. Vertical grouting pipe, 3. Drainage and cleaning pipe, 4. Movable piston, 401. Traction rope, 5. Horizontal nozzle, 6. Electrically controlled gate valve assembly, 7. Wireless calcium ion concentration monitor, 8. Reverse filter screen, 9. Irregularly shaped end plate, 10. Water-stop rubber sleeve, 11. Connecting pipe section, 12. Stress strain gauge, 121. Temperature compensation plate, 122. Suspension compensation block, 123. Sensing sealing chamber, 13. Central control unit, 14. Pile tip, 15. U-shaped pipe, 16. Micro motor, 17. Mechanical linkage structure, 18. Return spring, 19. Longitudinal lead screw, 20. Guide rail, 21. Sealing plate, 22. Sealing protective shell, 23. Transmission nut, 24. Connecting rod, 25. Skeleton, 26. Soft silicone or polymer sponge. Detailed Implementation

[0052] Example 1

[0053] The present invention will be further described below with reference to specific embodiments. The following embodiments provide specific structures and dimensional standards, which will help those skilled in the art to further understand the specific structure of the present invention. Without departing from the basic structure of the present invention, appropriate adjustments can be made to the dimensions of the present invention, all of which fall within the protection scope of the present invention.

[0054] In this embodiment, as Figure 1 As shown, the intelligent grouting prestressed pipe pile 1 of this invention has a vertical grouting pipe 2 installed inside the skeleton 25. A drainage and cleaning pipe 3 is installed on the inner wall of the pipe pile 1. Multiple horizontal nozzles 5 are installed on the vertical grouting pipe 2, communicating with the surrounding soil. Each horizontal nozzle 5 is arranged inclined outwards and upwards at an angle of 3-5 degrees to the horizontal plane, with a spacing of 1.5m-1.8m along the axial direction of the pipe pile 1. Each horizontal nozzle 5 contains, in sequence towards the surrounding soil, an electrically controlled gate valve assembly 6, a wireless calcium ion concentration monitor 7, and a reverse filter 8. Sensing sealing chambers 123 are pre-embedded above and below the vertical grouting pipes 2 within the pipe pile 1. The sensing sealing chambers 123 contain, for example, […]. Figure 5 The sensing sealing assembly shown.

[0055] A movable piston 4 is installed inside the pipe pile 1. The movable piston 4 adopts a combination structure of high-strength wear-resistant rubber and steel disc and is connected to the drive motor of the central control unit 13 by a traction rope. The upper part of the pipe pile 1 is connected to the central control unit 13 through a vertical grouting pipe 2 and a drainage and cleaning pipe 3. The lower part of the pipe pile 1 is connected to the pile tip 14. A U-shaped pipe 15 is installed inside the pile tip 14 to connect the vertical grouting pipe 2 and the drainage and cleaning pipe 3, forming a vertical pipeline system.

[0056] In this embodiment, as Figure 2As shown, irregularly shaped end plates 9 are installed at both ends of the pipe pile 1. In actual construction, these plates are used to connect multiple sections of pipe pile 1, depending on the length requirements of the pipe pile 1. The irregularly shaped end plates 9 have through holes corresponding to the pipe pile 1 and the vertical grouting pipe 2. The upper concave ring of the irregularly shaped end plate 9 faces outwards, and the lower convex ring faces outwards. A connecting pipe section 11 is installed inside the concave ring, and a water-stop rubber sleeve 10 is installed inside the convex ring. When the upper and lower pipe piles are connected, the connecting pipe section 11 is precisely inserted into the water-stop rubber sleeve 10. After the connection is completed, the edges of the irregularly shaped end plates 9 are welded and fixed around the perimeter and then lowered to the designed depth.

[0057] In this embodiment, as Figure 3 As shown, the transverse nozzles 5 are arranged at an angle of 3 to 5 degrees to the horizontal plane, which is used to allow the cementing liquid in the soil layer to flow smoothly into the transverse nozzles 5 in the diversion mode of the pipe pile 1. The spacing of the transverse nozzles 5 along the axial direction of the pipe pile 1 is 1.5m to 1.8m. Inside the transverse nozzles 5, the electrically controlled gate valve assembly 6, the wireless calcium ion concentration monitor 7 and the reverse filter screen 8 are arranged in sequence from the pipe pile to the soil outside the pile.

[0058] In this embodiment, as Figure 4 As shown, each electrically controlled gate valve assembly 6 for controlling the opening and closing of the transverse nozzle 5 is integrated within a sealed protective housing 22. This electrically controlled gate valve assembly 6, arranged longitudinally along the pipe pile, includes a micro motor 16, a return spring 18, a mechanical linkage structure 17, and a sealing plate 21. The mechanical linkage structure 17 includes a longitudinal lead screw 19, a transmission nut 23, and a connecting rod 24. The mechanical linkage structure 17 is connected to the micro motor 16 via the longitudinal lead screw 19. The return spring 18 and the transmission nut 23 are fitted onto the longitudinal lead screw 19. The transmission nut 23 is rigidly connected to the sealing plate 21 via the connecting rod 24. When energized, the micro motor 16 drives the longitudinal lead screw 19 to rotate, causing the transmission nut 23 to move longitudinally upward under the constraint of the guide rail 20, compressing the return spring 18 and driving the sealing plate 21 upward, thus opening the transverse nozzle 5. When de-energized, the compressed return spring 18 pushes the transmission nut 23 and the sealing plate 21 downward, achieving automatic reset and sealing of the transverse nozzle 5.

[0059] In this embodiment, Figure 5This is a schematic diagram of the sensing sealing chamber assembly. The sensing sealing chamber 123 is installed on the side wall of the vertical grouting pipe 2 and located at the monitoring section. The strain gauge 12 serves as the working gauge and is tightly attached to the frame 25. A suspended compensation block 122, made of the same material as the frame, is located within a 2cm to 5cm radius to its side. This suspended compensation block 122 is adhered to the soft silicone or polymer sponge 26 on the sealing chamber, ensuring it does not deform with the pile body. This aims to achieve stress isolation and thermal synchronization with the frame, thus providing a thermal strain reference for the temperature compensation plate 121 adhered to its surface, which does not participate in the pile body's load-bearing capacity and only fluctuates with the temperature field. The strain gauge 12, temperature compensation plate 121, and suspended compensation block 122 are sealed and fixed within the sensing sealing chamber 123 on the frame 25. Within the sensing sealed chamber 123, when the central control unit 13 drives the heating device, causing a localized temperature rise, the changes in thermal resistance generated by the stress strain gauge 12 and the temperature compensation gauge 121 are equal. Through the cancellation effect of adjacent arms of the Wheatstone bridge, the electrical signal output by the system eliminates temperature interference and only represents the increase in mechanical force caused by the change in soil properties. This in-situ physical compensation logic avoids complex algorithmic prediction models and exhibits extremely high reliability in complex underground grouting environments.

[0060] In this embodiment, Figure 6 This is a schematic diagram of an intelligent grouting prestressed pipe pile for EICP or MICP reinforcement. The arrows in the diagram indicate the approximate flow direction of the binder. The stress strain gauge 12 inside the pipe pile 1 determines the range of the soil layer to be reinforced using formula (2) in Example 2. When reinforcement begins, the pipe pile 1 starts the grouting mode. The sealing plate 21 inside the transverse nozzle 5 at the same depth as the soil layer to be reinforced is opened by the central control unit 13. The central control unit 13 heats the EICP or MICP binder to a specified temperature and injects it into the vertical grouting pipe 2 according to the set grouting pressure. The binder pushes the movable piston 4 to move, driving the traction rope to the predetermined position, i.e., below the transverse nozzle 5. The movable piston 4 restricts the flow space of the binder, thereby reducing the amount of binder used. The binder in the vertical grouting pipe 2 is injected into the soil layer to be reinforced through the transverse nozzle 5.

[0061] During grouting of this pipe pile, the adjacent pipe pile is controlled to activate the diversion mode. The movable piston 4 moves above the transverse nozzle 5 at the depth of the grouting and reinforcement soil layer, and opens the lower transverse nozzle 5. The central control unit 13 of the adjacent pipe pile activates the water pump jet suction device to perform negative pressure suction, inducing the cementing liquid injected into the soil layer by this pile to diffuse towards the adjacent pipe pile. Under the grouting pressure of this pipe pile and the negative pressure suction of the adjacent pipe pile, the cementing liquid in the reinforcement soil layer flows into the inclined transverse nozzle 5 opened by the adjacent pipe pile, and flows into the vertical pipeline system composed of the vertical grouting pipe 2, U-shaped pipe 15 and drainage and cleaning pipe 3 under the action of gravity. When the calcium ion concentration value measured by the wireless calcium ion concentration monitor 7 in the transverse nozzle 5 is close to the calcium ion concentration of the grouting pile nozzle, the sealing plate 21 is closed. The reaction progress is judged by the feedback of the wireless calcium ion concentration monitor 7. When the change of calcium ion concentration monitored by the wireless calcium ion concentration monitor 7 tends to be stable, it indicates that the reinforcement is completed.

[0062] Repeat the above grouting and drainage modes. When the real-time monitored side friction resistance reaches the design threshold, the calcium ion concentration drops back to near the initial background value, and the concentration change curve tends to stabilize, the reinforcement is considered complete. The central control unit 13 instructs the micro motor 16 to de-energize, and the sealing plate 21 is automatically sealed by the return spring 18. The pipeline system is cleaned in a closed loop using the U-shaped pipe 15 loop. The central control unit 13 instructs the movable piston 4 to perform a full-stroke reciprocating motion, and the side wall of the movable piston 4 is used to physically scrape the pipe wall. Combined with the water flow in the U-shaped pipe 15, the residual grout in the pipeline is thoroughly cleaned.

[0063] The construction spacing between two adjacent pipe piles is constrained by both soil permeability and grout crystallization time.

[0064] 1. Reference values ​​for parameters for different strata:

[0065] For medium to coarse sand formations (permeability coefficient) Due to its low pore resistance, the maximum effective drainage distance can reach 6.0m. The construction spacing L is dynamically determined based on the permeability coefficient of the soil layer to be reinforced, and is preferably 3.0m~5.0m. For silty fine sand strata (permeability coefficient... Due to increased capillary resistance, the maximum effective drainage distance is approximately 4.5m, and the preferred construction spacing L is 2.5m~3.5m; for silty clay layers (permeability coefficient... Due to its poor permeability (m / s), the construction spacing L should be reduced to 1.2m~1.8m.

[0066] 2. Online determination of optimal spacing:

[0067] The central control unit 13 uses a built-in Darcy's law model to predict the grout migration rate. If the measured calcium ion penetration time exceeds the preset grout initial setting time, the system automatically determines that the current spacing L is close to the physical limit and suggests using a larger grouting pressure or negative pressure in subsequent reinforcement.

[0068] Example 2

[0069] In an embodiment of the present invention, Figure 7 The diagram illustrates the functional modules. The intelligent pipe pile of this invention automates the biochemical reinforcement process through a closed-loop control system. The central control unit 13, as the core processing module, interacts bidirectionally with the cloud platform via a wireless communication module, enabling remote monitoring and command issuance. Simultaneously, it acquires multi-dimensional information in real time, including temperature, flow rate, pressure, calcium ion concentration, and pile stress and strain. Based on the judgment logic of the central control unit, it precisely drives the heating device, pressure controller, micro-drive components, and piston displacement mechanism through the execution control layer, thereby achieving refined control and guided diffusion of the EICP / MICP mineralization reaction environment. The judgment logic of the central control unit 13 is as follows:

[0070] 1. Real-time multidimensional data acquisition

[0071] The central control unit 13 synchronously acquires five key types of information about the pile body and the environment through the data acquisition layer:

[0072] Mechanical information: Electrical signals from strain gauges 12 at each layer are acquired via wires and converted into raw strain values. ;

[0073] Temperature information: The initial temperature of the slurry and the ambient temperature T are obtained in real time through a temperature sensor;

[0074] Chemical information: Real-time calcium ion concentration at the nozzle is acquired via a wireless calcium ion concentration monitor 7. ;

[0075] Fluid information: Instantaneous flow rate V and pipe pressure P during the grouting / suction process are obtained through flow rate sensors and pressure controllers.

[0076] 2. Intelligent data preprocessing and temperature correction

[0077] To address the active thermal field fluctuations generated by the heating device during EICP or MICP reactions, the system employs a dual correction logic combining physics and algorithms to eliminate interference from non-mechanical deformation.

[0078] Physical-level initial compensation: By using the stress-strain gauge 12 and temperature compensation gauge 121, which are in the same micro-environment within the sensing sealed chamber 123, a differential bridge is formed to immediately filter out the large background temperature drift (temperature spurious strain) caused by ambient temperature fluctuations at the signal generation end.

[0079] Algorithm-level secondary refinement: The central control unit 13 extracts the real-time acquired temperature T and flow rate V, and combines them with the preset longitudinal skeleton thermal expansion coefficient and sensor sensitivity temperature drift model to digitally correct the residual error after physical compensation, thereby obtaining the pure mechanical strain value ε that reflects the change in soil cementation strength. σ .

[0080] 3. Inverse calculation of pile axial force and side friction

[0081] Axial force calculation: The system calculates the actual axial force at each monitoring section based on the preset composite modulus E and cross-sectional area A of the pile body.

[0082] (1)

[0083] In the formula: Q is the actual axial force at the monitoring section; E is the composite modulus of the pile body; A is the cross-sectional area; ε σ To monitor the pure mechanical strain value of the cross-section.

[0084] Gradient analysis: The system calculates the axial force difference between two adjacent nozzle layers, and combines this with the pile perimeter U and the vertical spacing L between adjacent working strain gauges to invert and obtain the real-time side friction of the soil layer in this section.

[0085] (2)

[0086] In the formula: f s ΔQ represents the real-time side friction resistance; ΔQ represents the difference in actual axial force between two adjacent monitoring sections; U represents the pile circumference; and L represents the vertical spacing between adjacent working strain gauges.

[0087] 4. Status assessment throughout the reinforcement process

[0088] The system performs dynamic monitoring based on dual "mechanical-chemical" indicators:

[0089] Initial state (background determination): Before grouting, the system records the initial side friction resistance f. s0 and initial calcium ion background value , serving as the zero-point reference for judgment;

[0090] Reinforcement dynamic monitoring: The system monitors in real time during the EICP / MICP grouting process. with f s Evolution of:

[0091] 1) Period of intense reaction: If The concentration remained high, and f s The value showed a significant upward trend over time, indicating that the biochemical mineralization reaction was proceeding efficiently. The current heating power and grouting pressure P were maintained.

[0092] 2) Abnormal judgment: If the pressure P suddenly increases and the flow rate V suddenly decreases, it is judged that local pore blockage has occurred, and the system instructs the pressure controller to perform pulse pressure regulation.

[0093] 5. Automatic sealing and completion threshold determination

[0094] The system executes a dual cutoff logic of "slope + threshold". The soil layer is deemed adequately reinforced when both of the following conditions are met:

[0095] Condition A (Mechanical Indicator): Real-time side friction resistance f s growth slope Δf s / Δt tends to level off (close to 0), and its absolute value reaches the preset design strength threshold f;

[0096] Condition B (Chemical Indicator): The monitored calcium ion concentration continuously declines from its peak and approaches the initial background value. This indicates that the reactants have been completely consumed and the mineralization reaction is basically complete.

[0097] Action execution: Once qualified, the central control unit 13 immediately instructs the corresponding micro motor 16 to cut off the power, and uses the reset spring 18 to automatically reset the sealing plate 21 and block the nozzle. Then, the U-shaped pipe 15 is started to perform the automatic cleaning process.

[0098] Example 3

[0099] The method and procedure for using the device of the present invention are as follows:

[0100] Step 1: Pile driving and pipeline connection

[0101] According to project requirements, the intelligent grouting prestressed pipe pile consists of multiple pipe pile sections 1 connected together, including an upper section and a lower section. The upper section is lifted, and the convex ring of the irregularly shaped end plate 9 at the bottom of the upper section engages physically with the concave ring of the irregularly shaped end plate 9 at the top of the lower section. During this process, the protruding connecting pipe section 11 of the lower section automatically inserts into the water-stop rubber sleeve 10 at the interface of the upper section. After confirming a sealed connection, the edges of the irregularly shaped end plates of the two pile sections are welded around their perimeter.

[0102] Step 2: Initial Data Acquisition and Environmental Warm-up

[0103] After pile driving is completed, the central control unit 13 activates the stress-strain gauge 12 and the wireless calcium ion concentration detection sensor 7. The stress-strain gauge 12, equipped with a temperature self-compensation structure, collects the initial side friction data of the soil layer, and the wireless calcium ion concentration monitor 7 collects the initial chemical background value of the soil layer's calcium ion concentration. If EICP reinforcement technology is used, the central control unit 13 activates the internal heating device to preheat the soil EICP cementitious liquid to the set reaction temperature (e.g., 30℃~35℃) to activate urease activity.

[0104] Step 3: Determining Side Friction Resistance and Reinforcement Range

[0105] The central control unit 13 uses a differential bridge between the temperature compensation plate 121 and the stress strain gauge 12 and a built-in algorithm to eliminate environmental interference, obtain the real-time axial force and side friction of the pile body, and upload them to the cloud platform. The cloud platform automatically compares the design requirement threshold, identifies the weak soil layer range with insufficient side friction, which in this embodiment is 10m~15m deep and sets it as the target reinforcement range.

[0106] Step 4: Negative pressure suction and active diffusion induction

[0107] During grouting reinforcement, the central control unit 13 instructs the movable piston 4 inside the pile to move below the transverse nozzle 5 at the target reinforcement layer to execute the grouting mode. The central control unit 13 activates its internal heating device to heat the cementing fluid to the preset reaction temperature and adjusts the grouting pressure through the pressure controller inside the central control unit 13, forcing the cementing fluid into the soil layer from the target nozzle through the vertical grouting pipe 2. When this pipe pile begins grouting reinforcement, the adjacent pipe pile executes the diversion mode, controlling the movable piston 4 inside to move upward above the transverse nozzle 5 at the target reinforcement depth. The electrically controlled gate valve assembly 6 of the transverse nozzle at the target depth is opened. The water pump jet suction device in the central control unit 13 is activated, forming a negative pressure suction channel in the pipe space below the position of the movable piston 4 in the drainage cleaning pipe 3, U-shaped pipe 15, and vertical grouting pipe 2. At this time, under the induction of the hydraulic gradient, the external cementing fluid flows through the soil between the piles to the adjacent pipe piles, effectively solving the problem of uneven diffusion and serious loss of biological slurry in the soil layer. When the calcium ion concentration measured by the wireless calcium ion concentration monitor 7 in the transverse nozzle 5 of the adjacent pipe pile is close to the calcium ion concentration at the nozzle of the grouting pile and falls back to the background value, it indicates that the cementing liquid reaction is complete.

[0108] Step 5: In-situ reinforcement grouting and reaction monitoring

[0109] After the induced diffusion is complete, the adjacent pipe piles are switched to grouting mode. The movable piston 4 moves down to seal the bottom, and the preheated biological slurry is injected into the soil layer through the vertical grouting pipe 2 using a high-pressure grouting pump. The biochemical reaction process is monitored in real time by the wireless calcium ion concentration monitor 7 at the nozzle, and this pipe pile is put into drainage mode. The above process is repeated until the calcium ion concentration tends to stabilize and the stress strain gauge 12 shows that the side friction resistance reaches the design standard. At this time, the micro drive component is instructed to release the reset spring and seal the nozzle.

[0110] Step 6: System loop cleaning

[0111] In response to the characteristic of EICP technology that easily generates mineralized scale in pipelines, after the reinforcement task is completed, the pipeline system is cleaned in a closed loop using the U-shaped pipe 15 loop. The central control unit 13 instructs the movable piston 4 to perform full-stroke reciprocating motion, and the side wall of the movable piston 4 is used to physically scrape the pipe wall. Combined with the water flow of the U-shaped pipe 15, the residual slurry in the pipeline is thoroughly cleaned.

Claims

1. An intelligent grouting prestressed pipe pile for EICP or MICP reinforcement, characterized in that, include: Pipe pile (1), wherein a vertical pipeline system is provided inside the pipe pile (1); The vertical piping system includes a vertically parallel grouting pipe (2), a drainage and cleaning pipe (3), and a U-shaped pipe (15) located inside the pile tip (14) for connecting the vertical grouting pipe (2) and the drainage and cleaning pipe (3). The movable piston (4) is installed inside the vertical grouting pipe (2) and can move vertically inside the vertical grouting pipe (2). It can block the vertical grouting pipe (2) at its stopping position to assist in switching between grouting mode and drainage mode. Multiple horizontal nozzles (5) are located at different heights of the vertical grouting pipe (2), connecting the vertical grouting pipe (2) and the soil outside the pile; The central control system includes a central control unit (13), an electric gate valve assembly (6), and a wireless calcium ion concentration monitor (7). The central control unit (13) is located on the upper part of the prestressed pipe pile and includes a water pump jet suction device and a pressure controller. The water pump jet suction device can change the internal pressure in the pipes below the position of the movable piston (4) in the U-shaped pipe (15), the drainage cleaning pipe (3) and the vertical grouting pipe (2), thereby cooperating with the movable piston (4) to switch the grouting mode and the drainage mode of the pipe pile (1). The electrically controlled gate valve assembly (6) is used to control the opening and closing of the transverse nozzle (5); The wireless calcium ion concentration monitor (7) is located inside the transverse nozzle (5). In grouting mode, it monitors the calcium ion concentration in the cementing fluid injected into the soil by the prestressed pipe pile. In drainage mode, it monitors the calcium ion concentration in the cementing fluid of the soil flowing into the transverse nozzle (5) from the soil. It is used to determine the degree of movement and diffusion of the cementing fluid and the degree of cementation.

2. The intelligent grouting prestressed pipe pile for EICP or MICP reinforcement according to claim 1, characterized in that, The movable piston (4) is connected to the central control unit (13) via a traction rope (401); In the drainage mode, the movable piston (4) moves to the horizontal nozzle (5) above the target depth and opens the horizontal nozzle (5) below the movable piston (4). The water pump jet suction device in the central control unit (13) forms a negative pressure liquid suction channel in the pipe space below the movable piston (4) in the drainage cleaning pipe (3), U-shaped pipe (15) and vertical grouting pipe (2). The hydraulic gradient guides the cementing liquid injected into the soil layer by the other prestressed pipe piles to flow towards the prestressed pipe pile, so as to improve the uniformity of EICP or MICP reinforcement at different distances of the prestressed pipe piles. In grouting mode, the movable piston (4) moves to the horizontal nozzle (5) below the target reinforced soil layer depth. The central control unit (13) activates the internal heating device to preheat the cementing liquid to the preset reaction temperature and adjusts the grouting pressure through the pressure controller in the central control unit (13) to press the cementing liquid into the soil layer through the vertical grouting pipe (2) from the target horizontal nozzle (5).

3. The intelligent grouting prestressed pipe pile for EICP or MICP reinforcement according to claim 1, characterized in that, The transverse nozzle (5) is arranged inclined upwards and outwards from the prestressed pipe pile; The transverse nozzle (5) is sequentially equipped with an electrically controlled gate valve assembly (6), a wireless calcium ion concentration monitor (7), and a reverse filter (8) facing the soil layer.

4. The intelligent grouting prestressed pipe pile for EICP or MICP reinforcement according to claim 1, characterized in that, A vertically distributed frame (25) is provided inside the pipe pile (1). A sensing sealing chamber (123) is provided on the frame (25). A self-compensating sensing unit is provided inside the sensing sealing chamber (123). The self-compensating sensing unit includes a suspended compensation block (122) adhered to the soft silicone or polymer sponge (26) on the inner wall of the sealing chamber (123), a stress strain gauge (12) attached to the frame (25), and a temperature compensation plate (121) attached to the surface of the suspended compensation block (122). The temperature compensation plate (121) can compensate for temperature changes at different underground depths, as well as temperature changes caused by heat conduction due to the flow of cementitious liquid after heating. The suspension compensation block (122) is made of the same material as the frame and is in a state of independent force from the frame (25); The stress strain gauge (12) and the temperature compensation gauge (121) are connected to the compensation circuit of the central control unit (13) to counteract thermal interference; the stress strain gauge (12) feeds back data to obtain the distribution of side friction resistance and determines the location of the weak interlayer; the central control unit (13) calculates the real-time side friction resistance of the prestressed pipe pile according to the axial stress gradient and determines the soil reinforcement range and effect accordingly.

5. The intelligent grouting prestressed pipe pile for EICP or MICP reinforcement according to claim 1, characterized in that, The cleaning circulation loop formed by the vertical grouting pipe (2), drainage cleaning pipe (3), and U-shaped pipe (15) can clean the residual EICP or MICP cementing liquid and its products in the pipeline after grouting is completed.

6. The intelligent grouting prestressed pipe pile for EICP or MICP reinforcement according to claim 1, characterized in that, The central control unit (13) also integrates a temperature sensor, a flow rate sensor, a drive motor, and a heating device to adjust the reaction environment of EICP or MICP cementing liquid and participate in the realization of grouting mode and drainage mode.

7. The intelligent grouting prestressed pipe pile for EICP or MICP reinforcement according to claim 1, characterized in that: Each of the electrically controlled gate valve assemblies (6) used to control the switching of the transverse nozzle (5) is integrated into a sealed protective shell (22); the sealed protective shell (22) is provided with a micro drive assembly, including a micro motor (16), a return spring (18), a mechanical linkage structure (17) and a sealing plate (21) connected in sequence; the mechanical linkage structure (17) includes a longitudinal lead screw (19), a transmission nut (23) and a connecting rod (24), the longitudinal lead screw (19) is connected to the micro motor (16), the return spring (18) and the transmission nut (23) are sleeved on the longitudinal lead screw (19), and the transmission nut (23) is rigidly connected to the sealing plate (21) through the connecting rod (24); When powered on, the micro motor (16) can drive the mechanical linkage structure (17) to move the sealing plate (21) to open the transverse nozzle (5); when powered off, the reset spring (18) can drive the sealing plate (21) to reset to block the transverse nozzle (5).

8. The intelligent grouting prestressed pipe pile for EICP or MICP reinforcement according to claim 1, characterized in that, The prestressed pipe pile consists of multiple pipe pile sections (1) connected longitudinally by irregular end plates (9). One side of the irregular end plate (9) is a concave ring with an annular groove, and the other side is a convex ring with a protruding ring. Both the concave and convex rings are provided with through holes corresponding to the vertical grouting pipe (2). The convex and concave fit between the irregular end plates (9) ensures the sealing connection of the grout channel. Each section of the pipe pile (1) is provided with a special-shaped end plate (9) at the upper and lower ends respectively. The concave ring of the special-shaped end plate (9) at the upper end of the pipe pile (1) faces upward and a connecting pipe section (11) protruding from the end face is provided in the through hole. The convex ring of the special-shaped end plate (9) at the lower end of the pipe pile (1) faces downward and a water-stop rubber sleeve (10) is provided in the through hole.

9. A construction method based on the prestressed pipe pile according to any one of claims 1-8, comprising: Step 1: Install prestressed concrete pipe piles; Step 2: The wireless calcium ion concentration monitor (7) collects the initial chemical background value of the calcium ion concentration in the soil layer, and the stress strain gauge (12) collects the original strain signal; the central control unit (13) obtains the background data of the initial axial force and side friction of the pile body through the differential bridge of the temperature compensation plate (121) and the stress strain gauge (12) and the built-in algorithm, monitors the side friction distribution of each monitoring section, and determines the location of the weak soil layer with missing side friction by the change of axial force gradient between adjacent sections, and sets it as the target reinforcement range; Step 3: The movable piston (4) inside the command pile moves to the horizontal nozzle (5) below the target reinforcement layer to execute the grouting mode. The central control unit (13) starts the internal heating device to preheat the cementing liquid to the preset reaction temperature, and adjusts the grouting pressure through the pressure controller in the central control unit (13). The cementing liquid used for soil reinforcement is pressed into the soil layer from the horizontal nozzle (5) of the target through the vertical grouting pipe (2). Step 4: When the adjacent prestressed pipe pile is grouting, the movable piston (4) of this prestressed pipe pile is moved to the horizontal nozzle (5) above the grouting reinforcement soil layer depth to execute the diversion mode. The central control unit (13) opens the horizontal nozzle (5) below the movable piston (4) and opens the water pump jet suction device in the central control unit (13) to form a negative pressure in the vertical grouting pipe (2), U-shaped pipe (15) and drainage cleaning pipe (3), inducing the cementing liquid injected into the soil layer by the adjacent pipe pile to diffuse towards this pile. When the cementing liquid in the reinforcement soil layer flows into the inclined horizontal nozzle (5) of the adjacent pipe pile, and the calcium ion concentration value measured by the wireless calcium ion concentration monitor (7) in the horizontal nozzle (5) is close to the calcium ion concentration of the grouting pile nozzle, the horizontal nozzle (5) is closed. Step 5: When the change in calcium ion concentration value monitored by the wireless calcium ion concentration monitor (7) tends to be stable, alternate between grouting mode and drainage mode, and repeat the above steps 3 to 4. When the side friction resistance monitored in real time reaches the design threshold and the calcium ion concentration drops back to the background value, the reinforcement operation is completed.

10. The construction method according to claim 9, further comprising: After the reinforcement work is completed, open the bottom horizontal nozzle (5), start the water pump jet suction device to generate negative pressure, and suck the remaining cementing liquid waste in the soil around the pile into the pipe space below the movable piston (4) in the drainage cleaning pipe (3), U-shaped pipe (15) and vertical grouting pipe (2), and then suck it into the central control unit (13) for harmless treatment before discharge.

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