A method and related device for identifying defects of rotary jetting piles based on distributed optical fiber sensing technology

Abstract

The application provides a rotary jetting pile defect identification method based on a distributed optical fiber sensing technology and a related device, and belongs to the technical field of rotary jetting pile body quality detection.The application binds strain data, temperature data and vibration data with the axial position of a distributed optical fiber sensing unit to obtain strain curves, temperature curves and vibration curves;obtains real-time strain data, real-time temperature data and real-time vibration data in the strain curves, the temperature curves and the vibration curves;compares the real-time strain data, the real-time temperature data and the real-time vibration data in the strain curves, the temperature curves and the vibration curves with pre-set strain data, temperature data and vibration data abnormal mutation determination thresholds to obtain the characteristics of strain data, temperature data and vibration data abnormal mutation;and determines the defect type of the rotary jetting pile according to the characteristics of strain data, temperature data and vibration data abnormal mutation.The application solves the problem of low accuracy of rotary jetting pile defect identification.

Description

Technical Field

[0001] This invention belongs to the field of jet grouting pile quality inspection technology, specifically relating to a method and related device for identifying defects in jet grouting piles based on distributed optical fiber sensing technology. Background Technology

[0002] Jet grouting is a core technology for soft soil foundation reinforcement. Current construction quality control mostly relies on post-construction core drilling and low-strain testing, which have problems such as delayed detection, inability to achieve continuous monitoring throughout the entire cycle, and insufficient accuracy in defect identification.

[0003] Some existing technologies use parameters such as grouting pressure and flow rate during construction, or single-type fiber optic sensing monitoring. These technologies require multi-parameter coupling to calculate indicators such as soil and pile impermeability and leakage index. They have limitations such as complex calculation process, large susceptibility to environmental interference, low accuracy of defect identification, and inability to achieve full-length distributed monitoring. They are difficult to meet the real-time quality control requirements of the entire construction cycle of jet grouting piles. Summary of the Invention

[0004] The purpose of this invention is to provide a method and related device for identifying defects in jet grouting piles based on distributed optical fiber sensing technology, in order to solve the problem of low accuracy in identifying defects in existing jet grouting piles.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for identifying defects in jet grouting piles based on distributed optical fiber sensing technology, comprising the following steps: During the construction of jet grouting piles, the wavelength signal of the distributed optical fiber sensing unit is acquired; The wavelength change is obtained based on the wavelength signal from the distributed optical fiber sensing unit. The wavelength change is converted into strain data, temperature data, and vibration data; By binding strain data, temperature data, and vibration data with the axial position of the distributed fiber optic sensing unit, strain curves, temperature curves, and vibration curves are obtained. Acquire real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves; The real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve are compared with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. Based on the characteristics of abnormal abrupt changes in strain, temperature, and vibration data, the defect type of the jet grouting pile is determined.

[0006] A further improvement of the present invention is that the distributed optical fiber sensing unit adopts an integrated stainless steel sealed package.

[0007] A further improvement of the present invention is that the threshold for determining abnormal mutations is determined based on geological conditions, construction techniques, and preliminary test data.

[0008] A further improvement of this invention lies in that, specifically, determining the defect type of the jet grouting pile based on the characteristics of abnormal abrupt changes in strain data, temperature data, and vibration data is as follows: If the strain data shows a negative abrupt change, the temperature data shows a positive abrupt change, and the vibration data shows a high-frequency abrupt change, then the jet grouting pile is determined to be a leak point defect. If the strain data shows a positive abrupt change, the temperature data shows a positive abrupt change, and the vibration data shows a low-frequency abrupt change, then the jet grouting pile is determined to have a diameter reduction defect. If the strain data shows a step change, the temperature data shows a step change, and the vibration data shows an impact change, then the jet grouting pile is determined to be a broken pile defect.

[0009] A further improvement of this invention is that if the jet grouting pile is determined to be a leak, the construction personnel will immediately carry out re-grouting and patching operations to seal the leakage location.

[0010] A further improvement of the present invention is that if the jet grouting pile is determined to have a diameter reduction defect, the construction personnel adjust the grouting pressure and grout flow rate, and repeat the grouting in the defective section to make up for the cross-section of the pile.

[0011] A further improvement of this invention is that if a jet grouting pile is determined to be a broken pile defect, all construction shall be stopped immediately.

[0012] Secondly, the present invention provides a jet grouting pile defect identification system based on distributed optical fiber sensing technology, comprising: The data acquisition module is used to acquire the wavelength signal of the distributed optical fiber sensing unit during the jet grouting pile construction process. The wavelength change determination module is used to obtain the wavelength change based on the wavelength signal from the distributed optical fiber sensing unit. The conversion module is used to convert wavelength changes into strain data, temperature data, and vibration data. The curve plotting module is used to bind strain data, temperature data, and vibration data with the axial position of the distributed fiber optic sensing unit to obtain strain curves, temperature curves, and vibration curves. Acquire real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves; The comparison module is used to compare the real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data, so as to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. The defect type determination module is used to determine the defect type of the jet grouting pile based on the characteristics of abnormal changes in strain data, temperature data, and vibration data.

[0013] Thirdly, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the jet grouting pile defect identification method based on distributed optical fiber sensing technology described above.

[0014] Fourthly, the present invention provides a storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the jet grouting pile defect identification method based on distributed optical fiber sensing technology described above.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The proposed defect identification method for jet grouting piles based on distributed optical fiber sensing technology has two main aspects. First, during the jet grouting pile construction process, the wavelength signal of the distributed optical fiber sensing unit is acquired, significantly reducing missed identifications at the sampling level. Second, strain data, temperature data, and vibration data are bound to the axial position of the distributed optical fiber sensing unit to obtain strain curves, temperature curves, and vibration curves. This operation can completely preserve the response morphology and change law of different pile defects in the corresponding axial segment. Furthermore, the real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve are compared with pre-set abnormal change judgment thresholds for strain data, temperature data, and vibration data to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. Thus, this invention provides a unified judgment standard and eliminates subjective human error. Attached Figure Description

[0016] Figure 1 This is a flowchart of the jet grouting pile defect identification method based on distributed optical fiber sensing technology of the present invention; Figure 2 This is a schematic diagram of the jet grouting pile defect identification system based on distributed optical fiber sensing technology of the present invention; Figure 3 This is a schematic diagram of the structure of the electronic device of the present invention. Detailed Implementation

[0017] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0018] Example 1: The flowchart of the jet grouting pile defect identification method based on distributed optical fiber sensing technology of this invention is as follows: Figure 1 As shown, the defect identification method for jet grouting piles based on distributed optical fiber sensing technology of the present invention includes the following steps: S1. During the jet grouting pile construction process, acquire the wavelength signal of the distributed optical fiber sensing unit; S2. Based on the wavelength signal of the distributed optical fiber sensing unit, the wavelength change is obtained; S3. Convert the wavelength change into strain data, temperature data, and vibration data; S4. Bind the strain data, temperature data, and vibration data to the axial position of the distributed fiber optic sensing unit to obtain the strain curve, temperature curve, and vibration curve. S5. Obtain real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves; S6. Compare the real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. S7. Determine the defect type of the jet grouting pile based on the characteristics of abnormal changes in strain data, temperature data, and vibration data.

[0019] Example 2: A schematic diagram of the jet grouting pile defect identification system based on distributed optical fiber sensing technology of this invention is shown below. Figure 2 As shown, the jet grouting pile defect identification system based on distributed optical fiber sensing technology of the present invention includes: The data acquisition module is used to acquire the wavelength signal of the distributed optical fiber sensing unit during the jet grouting pile construction process. The wavelength change determination module is used to obtain the wavelength change based on the wavelength signal from the distributed optical fiber sensing unit. The conversion module is used to convert wavelength changes into strain data, temperature data, and vibration data. The curve plotting module is used to bind strain data, temperature data, and vibration data with the axial position of the distributed fiber optic sensing unit to obtain strain curves, temperature curves, and vibration curves. Acquire real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves; The comparison module is used to compare the real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data, so as to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. The defect type determination module is used to determine the defect type of the jet grouting pile based on the characteristics of abnormal changes in strain data, temperature data, and vibration data.

[0020] Example 3: The present invention provides a defect identification method for jet grouting piles based on distributed optical fiber sensing technology, comprising the following steps: S1. During the jet grouting pile construction process, acquire the wavelength signal of the distributed optical fiber sensing unit.

[0021] In this step, the distributed fiber optic sensing unit is encapsulated in an integrated stainless steel sealed package.

[0022] S2. Based on the wavelength signal of the distributed optical fiber sensing unit, the wavelength change is obtained.

[0023] S3. Convert the wavelength change into strain data, temperature data, and vibration data.

[0024] S4. Bind the strain data, temperature data, and vibration data to the axial position of the distributed fiber optic sensing unit to obtain the strain curve, temperature curve, and vibration curve.

[0025] S5. Obtain real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves.

[0026] S6. Compare the real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data.

[0027] The threshold for determining abnormal mutations in this step is determined based on geological conditions, construction techniques, and preliminary test data.

[0028] S7. Determine the defect type of the jet grouting pile based on the characteristics of abnormal changes in strain data, temperature data, and vibration data.

[0029] This step determines the defect type of the jet grouting pile based on the characteristics of abnormal abrupt changes in strain, temperature, and vibration data. Specifically: If the strain data shows a negative abrupt change, the temperature data shows a positive abrupt change, and the vibration data shows a high-frequency abrupt change, then the jet grouting pile is determined to be a leak point defect. If the strain data shows a positive abrupt change, the temperature data shows a positive abrupt change, and the vibration data shows a low-frequency abrupt change, then the jet grouting pile is determined to have a diameter reduction defect. If the strain data shows a step change, the temperature data shows a step change, and the vibration data shows an impact change, then the jet grouting pile is determined to be a broken pile defect.

[0030] If the jet grouting pile is determined to be a leak point during this step, the construction personnel will immediately carry out re-grouting and patching operations to seal the leaking location.

[0031] If the jet grouting pile is determined to have a diameter reduction defect in this step, the construction personnel will adjust the grouting pressure and grout flow rate, and repeat the grouting in the defective section to make up for the cross-section of the pile.

[0032] If the jet grouting pile is determined to be a broken pile defect during this step, all construction should be stopped immediately.

[0033] Example 4: The method of this invention adopts distributed optical fiber sensing technology. By pre-embedding a special composite optical cable integrating three types of sensing units—strain, temperature, and vibration—with fiber optic demodulation equipment, data processing terminal, and construction management platform before jet grouting pile construction, real-time monitoring of the entire length of the pile body is achieved throughout the entire cycle of jet grouting pile drilling, grouting, pile formation, and curing. Defects such as leaks, diameter reduction, and pile breakage are identified by direct abnormal changes in strain, temperature, and vibration signals, without the need to calculate indirect parameters such as soil impermeability coefficient and leak index.

[0034] In this embodiment, the fiber optic demodulation equipment (hereinafter referred to as the demodulation equipment) adopts a wavelength scanning fiber optic grating demodulator. The built-in functional modules of the wavelength scanning fiber optic grating demodulator have wavelength signal acquisition, signal conversion and curve generation functions.

[0035] The jet grouting pile defect identification method of the present invention using distributed optical fiber sensing technology is specifically implemented based on a jet grouting pile defect identification system (hereinafter referred to as the system) using distributed optical fiber sensing technology. The method of the present invention will be described in detail below: Step 1: Preliminary System Customization and On-site Survey and Calibration Step one specifically includes: 1. Collection and sorting of basic engineering parameters Before formally commencing system customization, a comprehensive set of data for the target jet grouting pile project was collected, including the overall construction plan, individual pile design drawings, detailed geological survey reports, underground pipeline detection reports, and on-site environmental monitoring records. The core technical parameters of each jet grouting pile were then extracted one by one, specifically: The designed pile length ranges from 8.6m to 22.3m, with two pile diameter specifications: 600mm and 800mm. The designed conventional grouting pressure is 22MPa, with the pressure increased to 25MPa for special soft strata. The standard drill rod lifting speed is 18cm / min, reduced to 12cm / min for hard interlayer strata. Stratigraphic information is simultaneously compiled, from top to bottom: miscellaneous fill layer, silty soft soil layer, silty clay layer, medium-coarse sand layer, and strongly weathered bedrock. The thickness, soil moisture content, density, and normal ground temperature of each layer are recorded. Groundwater level depth, stratum corrosivity level, and sections prone to borehole wall collapse are also marked. All parameters are recorded electronically by pile location number, serving as the core basis for customizing sensor cables and sensor units, ensuring complete matching of equipment specifications with on-site conditions.

[0036] 2. Customization of sensor optical cable structure and specifications A custom-designed composite sensing optical cable was developed, taking into account factors such as pile length, geological environment, high-pressure grouting impact, and drill rod friction. The cable adopts a central bundled tube composite structure, with a total length configured according to the single pile design length plus a 1.4m redundancy section. The 0.3m redundancy section inside the hole is used to compensate for length deviations caused by pile bottom sediment and drilling disturbance, while the 1.1m lead-in section outside the hole is specifically used for laying connectors and connecting demodulation equipment. Throughout the entire process, the fiber optic connectors are kept away from the grouting slurry and groundwater soaking areas.

[0037] The optical cable's layered structure and parameters from the inside out are as follows: The first layer is a single-mode optical fiber core with a core diameter of 9μm and a cladding diameter of 125μm, featuring low loss and bending resistance. The second layer is a polyimide tight-fitting layer with a thickness of 0.14mm, which is resistant to high temperatures and cement hydration deformation, and can withstand short-term high temperatures of 120℃. The third layer is a low-density polyethylene buffer layer with a thickness of 0.9mm, which has excellent elastic buffering performance and can absorb mechanical loads generated by high-pressure slurry impact and drill pipe scraping. The fourth layer is a metal armor layer, which is made of 304 stainless steel wire with a diameter of 0.25mm spirally woven, with a braiding density strictly controlled at 87% and a braiding pitch of 12mm, providing all-round resistance to shearing, friction, and high-pressure erosion. The outermost layer is a polyurethane outer sheath with a thickness of 1.6mm, which is waterproof, resistant to soil corrosion, and anti-aging, and suitable for damp and slightly corrosive underground strata.

[0038] The overall outer diameter of the optical cable is controlled at 7.2mm, and the minimum bending radius is 12 times the outer diameter of the optical cable. During the production process, each reel is subjected to a water pressure test at a pressure of 28MPa. Only after the pressure is maintained for 30 minutes without leakage or structural deformation can the cable be shipped out.

[0039] 3. Layout planning and integration of fiber Bragg grating sensing units Multiple composite sensing units are integrated along the axis of the customized optical cable. Each unit independently integrates a fiber optic strain unit, a fiber optic temperature unit, and a fiber optic vibration unit. The spectra of the three types of units are independent and free from crosstalk, and each unit is an independent monitoring node.

[0040] The unit layout is divided into zones with controlled spacing, specifically as follows: First, in the conventional strata section (silty clay and medium-coarse sand layers), the axial spacing between the centers of two adjacent sets of sensing units is uniformly set to 1.0m. Second, in the high-risk section at the pile top, i.e., the area within 3.0m below the pile top surface, this area is affected by surface disturbance, grout backflow, and pile head formation, resulting in a high incidence of leakage points and diameter reduction defects. The units are densely arranged, and the spacing between adjacent centers is adjusted to 0.5m. Third, in the high-risk section at the pile bottom, i.e., the area within 2.0m above the pile bottom, this area is prone to pile breakage and bottom leakage problems due to the influence of sediment and the interface between soft and hard strata. The unit spacing is also densely arranged to 0.5m.

[0041] All sensing units are encapsulated in a single, sealed stainless steel enclosure with a wall thickness of 0.15mm. The enclosure is filled with thermally conductive and insulating silicone grease, ensuring a full and seamless seal. This silicone grease guarantees accurate transmission of strain, temperature, and vibration signals while also providing an IP68 waterproof rating, allowing for long-term immersion in cement slurry and groundwater, and resisting the instantaneous impact pressure generated by high-pressure grouting. All sensing units are simultaneously etched and integrated during the optical cable production stage, resulting in a seamless connection between the unit and the cable body without any protruding structures, preventing snagging on the borehole walls and soil during the lowering process.

[0042] 4. Sensor unit technical parameters and indoor calibration The three types of sensing units are each set with an independent center wavelength, measurement range, and resolution. Full-range indoor calibration is completed before leaving the factory to establish the correspondence curve between wavelength and physical quantity.

[0043] Fiber optic strain gauge unit: center wavelength 1529.6nm, wavelength resolution 0.8pm, effective measurement range -1480με~+1490με, which can completely cover the deformation range of the pile body under compression, tension, contraction and expansion. Fiber Bragg grating temperature unit: center wavelength 1549.7nm, temperature resolution 0.18℃, measurement range -18℃~78℃, can monitor the normal temperature of the formation, the temperature rise of cement hydration, and the temperature change during post-curing. Fiber Bragg grating vibration unit: center wavelength 1569.5nm, frequency response range 12Hz~980Hz, acceleration range -9.7g~+9.8g, can identify different vibration characteristics such as drill rod rotation, grout injection, pile fracture, and soil slippage.

[0044] The calibration environment was set in a standard constant-temperature laboratory with an ambient temperature of 22℃ and humidity of 55%. The strain gauge unit employed a graded axial loading method, with each grade loading 100με and recording the corresponding wavelength value after 30 seconds of stabilization. The temperature unit used a gradient heating mode, with each 5℃ increment representing a gradient, and wavelengths were read after 5 minutes of stabilization. The vibration unit used a standard vibration table for graded excitation, testing and recording data sequentially according to frequency and gradient. All calibration data was automatically entered into the built-in database of the fiber optic demodulation equipment. The equipment can automatically perform real-time conversion between wavelength and physical quantities based on the calibration curve, and the calibration report is archived with the equipment.

[0045] 5. On-site benchmark data acquisition and threshold pre-configuration After the optical cables and demodulation equipment arrive on site and undergo initial visual and power-on inspections, on-site benchmark data collection is carried out at the corresponding pile locations. Portable temperature and humidity detectors, high-precision vibration sensors, and static strain acquisition instruments are deployed within a 1m radius around the pile holes to be constructed, with the equipment 0.5m off the ground to avoid vibration interference from construction machinery.

[0046] Three sets of initial field data were continuously collected, with each set lasting 5 minutes and an interval of 1 minute between collections. After the first set of data was collected, the data was allowed to stand for 2 minutes before the second and third sets were collected. The collected data included static strain values ​​of the formation, initial average temperature of the formation, and amplitude of inherent minor vibrations of the formation. Significantly abnormal fluctuation values ​​were removed from the three sets of data, and the arithmetic mean of the valid data was taken. This value was set as the initial reference value for the full-cycle monitoring of this pile location and was simultaneously entered into the data processing terminal and fiber optic demodulation equipment.

[0047] Simultaneously, based on the geological report and construction parameters, the signal anomaly judgment thresholds determined in the early stage were preloaded into the equipment system: strain mutation threshold ±118με, temperature mutation threshold ±1.7℃, and vibration mutation threshold ±2.4g. The system was pre-configured and awaited the drilling operation.

[0048] Step 2: Piling and Pre-laying of Optical Cables Step two specifically includes: 1. Pre-construction equipment placement and pile location verification A total station was used to conduct a secondary verification and layout of the designed pile positions, marking the center point of the pile hole. Simultaneously, four directional control piles were laid out around the pile positions to facilitate verification of the drilling rig position during the drilling process. A matching jet grouting drilling rig and corresponding drill bits were selected: a Φ630mm drill bit for a 600mm pile diameter and a Φ830mm drill bit for an 800mm pile diameter, ensuring that the drilled hole diameter was 30mm larger than the designed pile diameter.

[0049] Once the drilling rig is positioned above the pile location, its levelness and verticality are adjusted. Using the rig's built-in plumb bob and inclination measuring device for double verification, the verticality deviation is strictly controlled within 0.2%. After the drilling rig is in place, the drill rod connection is checked for secureness, the grouting pipeline is sealed, and the air compressor is functioning correctly. The air pressure is confirmed to be stably maintained at 0.35 MPa. Drilling operations can only begin after all equipment is functioning normally.

[0050] 2. Pile hole drilling and slag removal operations Start the drilling rig and begin drilling. The drilling speed is controlled differentially based on the geological formation differences. Specifically: For conventional silty clay and miscellaneous fill layers, the drilling speed is set at 0.45 m / min; for silty soft soil layers, the speed is reduced to 0.38 m; and for medium-coarse sand and mixed soft and hard strata, the speed is further reduced to 0.32 m to prevent the drilling speed from disturbing the borehole wall and causing the borehole to collapse due to excessive speed.

[0051] The drilling depth is controlled according to the designed pile length + 0.6m. The over-drilled portion is reserved as space for sediment at the pile bottom. After the drilling rig reaches the designed depth, it is immediately stopped from lowering and the drill rod is slowly raised to the hole opening. Then, the air compressor is turned on and the annular purging nozzle is connected. The nozzle is lowered to the bottom of the hole, and dry compressed air at 0.35MPa is used to purge along the hole wall in a circular motion for a uniform duration of 90 seconds, cleaning the loose soil, loose debris, and fallen soil clods attached to the hole wall from top to bottom.

[0052] After purging, a measuring rope and a sediment measuring plate are used to check the thickness of the sediment at the bottom of the pile. The acceptable sediment thickness is ≤45mm. If the sediment exceeds the standard, the purging nozzle is lowered again for secondary cleaning until the standard is met. After cleaning, the hole is left to stand for 2 minutes to allow the airflow in the hole to stabilize completely and the suspended soil particles to settle before proceeding to the fiber optic cable pre-laying process.

[0053] 3. Assembly and pretreatment of optical cable end fittings An integrated streamlined stainless steel guide head is installed at the bottom of the optical cable. The guide head has a total length of 135mm, a maximum outer diameter of 20mm, and an overall cone angle of 28°. It is made of 304 stainless steel, which has rust-proof and wear-resistant properties. The outer wall of the guide head is evenly distributed with three rings of barbs, with 6 independent barbs in each ring. The height of each barb is 2.1mm, and the axial spacing between adjacent barbs is 36mm. The surface of the barbs is passivated. During the lowering process, it can assist in guiding and engaging the hole wall. During the grouting stage, it can effectively prevent the optical cable from floating and radially shifting.

[0054] The connection between the optical cable and the guide is sealed and reinforced, specifically as follows: Insert the end of the optical cable into the built-in connection slot of the guide head to a depth of 40mm. Fill the inside and outside of the slot with two-component epoxy resin sealant. The sealant curing layer is 2mm thick, completely sealing the gaps and preventing groundwater and cement slurry from seeping in and damaging the internal optical fiber and sensing unit.

[0055] At a distance of 1.7m from the fiber optic cable opening, pre-install a split-opening special cable clamp on the lead-in section outside the cable hole. The clamp has a 5mm thick anti-slip rubber pad on the inside and a fastening bolt on the outside for subsequent fiber optic cable fixing. Check the clamp's opening, closing, and fastening functions in advance to ensure normal operation.

[0056] 4. Uniform speed lowering of optical cable and attitude correction throughout the process The optical cable was lowered using a combination of manual labor and a small winch. The winch's traction force was kept constant at 95N to maintain the cable under slight tension throughout the process, preventing bending, kinking, and localized compression. The standard lowering speed was controlled at 0.6m / min. Two operators were assigned to the lowering process: one operated the winch to control the speed, and the other observed the cable's posture at the opening.

[0057] Define the segmented attitude detection rules as follows: After each 2.0m descent, immediately pause the winch operation. Place the portable digital inclinometer probe against the outer wall of the optical cable and slide it vertically along that section of the cable to check the verticality. The testing length for each section is 2.0m, and the allowable deviation for verticality is ≤0.3%. If the deviation exceeds the limit, immediately fine-tune the lateral support points of the winch and manually assist in straightening the optical cable until the verticality meets the standard before continuing the descent.

[0058] When the guide head contacts the soil at the bottom of the pile and encounters significant resistance, reduce the lowering speed to 0.2 m / min and slowly release the remaining cable, ensuring that the guide head is completely in contact with the bottom of the pile without any suspension, tilting, or lifting. After the entire optical cable is lowered into place, re-measure the verticality along its entire length to confirm that the overall posture meets the requirements.

[0059] 5. Fixing the fiber optic cable opening and debugging the line connection. After the optical cable is in place, the opening fixing work will be carried out, specifically as follows: Secure the pre-installed cable clamp onto the optical cable, align it with the pre-set mounting bracket on the drilling rig frame, and tighten the clamp bolts using a torque wrench, strictly controlling the tightening torque to 18N. m ensures a secure fixation while preventing the clamps from squeezing and damaging the outer sheath of the optical cable.

[0060] The external lead segment is regulated as follows: Flame-retardant nylon cable ties are used to bind the cables in sections, with a binding spacing of 30cm. The cables are allowed to bend naturally, with the bending radius always greater than 12 times the outer diameter of the optical cable. Sharp bends and abrupt angles are strictly prohibited. After binding, the fiber optic connectors are cleaned by wiping the connector ends with a dust-free non-woven cloth dampened with anhydrous alcohol to remove dust, water stains, and dirt, ensuring optical continuity.

[0061] After cleaning, precisely insert the fiber optic connector into the signal input port of the fiber optic demodulation equipment, and attach a matching waterproof and dustproof protective cap to the outside of the interface. After completing the hardware connection, start the fiber optic demodulation equipment. After a 3-minute warm-up period, wake up all sensor units and read the real-time signal. Compare the current signal with the previous field reference value to check the signal waveform continuity and wavelength stability, confirming there are no signal disconnections, wavelength drift, or unit failures. If signal anomalies occur, re-inspect the connector connections and fiber optic cable appearance to troubleshoot the problem; if the signal is normal, the pre-embedding work is considered complete, and the jet grouting construction phase begins.

[0062] Step 3: Real-time data acquisition and preliminary signal analysis during the jet grouting pile construction phase Step three specifically includes: Demodulation equipment parameter configuration and preheating are as follows: Start the wavelength scanning fiber optic demodulator. The device operates at AC220V and has a warm-up time of 8 minutes. Set the wavelength scanning range to 1520nm to 1580nm, covering the center wavelengths of all three types of sensing units. Set the basic scanning frequency to 160Hz, matching the conventional lifting speed of the jet grouting pile. Input the previously calibrated wavelength-strain, wavelength-temperature, and wavelength-vibration conversion formulas into the device's built-in system. Enable real-time data storage and curve generation functions. The storage format is a dual mode of local encrypted files and cloud synchronous backup, with a local data storage interval of 0.01s and a cloud synchronization interval of 0.05s. Simultaneously, set up a real-time signal display interface. The interface is divided into coordinates according to the axial length of the pile, simultaneously displaying three continuous distribution curves of strain, temperature, and vibration. The horizontal axis represents the pile depth, and the vertical axis represents the corresponding physical quantity values.

[0063] Before grouting, a secondary benchmark value verification was performed. Five sets of static signal data were continuously collected at 2-second intervals. After removing abnormal fluctuation data, the average value was taken and updated as the initial benchmark value for grouting operations. The temperature distribution at different depths of the pile was carefully checked to confirm that before the cement grout was injected, the temperature deviation between the borehole temperature and the previous stratum benchmark temperature was ≤1.0℃, the vibration signal maintained the inherent low amplitude state of the stratum, and the strain signal showed no significant fluctuations, confirming that the monitoring system was in a stable working state.

[0064] Simultaneous data acquisition during grouting operations: The jet grouting equipment is activated, employing conventional jet grouting technology. After the drill rod is lowered to the bottom of the pile, grout is sprayed upwards, with the drill rod lifting speed set at 20 cm / min. The corresponding demodulation equipment maintains a 160 Hz acquisition frequency, continuously acquiring wavelength signals from all sensor units throughout the process. During high-pressure grouting, the hydration heat release of the cement grout, grout impact, and drill rod disturbance will cause normal signal fluctuations. These fluctuations are normal process phenomena, and the equipment automatically distinguishes between normal and abnormal conditions. Every 1 meter of pile length, the system automatically marks the location node and archives the three sets of sensor data at that location in real time, ensuring a spatial resolution within 0.5m. During the acquisition process, a dedicated person monitors the demodulation equipment, observing the overall trend of the curve. If a large-scale, continuous signal abrupt change occurs, the grouting operation is immediately suspended for on-site investigation.

[0065] Real-time signal conversion and curve generation are specifically as follows: The demodulation device's built-in signal conversion module converts the acquired wavelength changes into corresponding physical quantities in real time: wavelength offset (wavelength change) corresponding to strain, temperature, and vibration values. The demodulation device's built-in curve generation module automatically binds the converted physical quantities to the axial position of the sensing unit, plotting a continuous distribution curve along the entire length of the pile. The strain curve reflects the deformation of the pile caused by grout compression and soil constraint; the temperature curve reflects the temperature change after the superposition of ground temperature and cement hydration; the vibration curve reflects the vibration amplitude and frequency generated by drill rod rotation, grout injection, and soil disturbance. The three curves are refreshed and displayed synchronously, with no data gaps throughout the entire process.

[0066] Step 4: Defect Identification During Construction Step four specifically includes: The abnormal thresholds are uniformly set based on geological conditions, construction techniques, and preliminary test data. Three types of abnormal signal mutation judgment thresholds are uniformly set as follows: The threshold for abrupt changes in strain signals relative to the reference value is ±118με, the threshold for abrupt changes in temperature signals relative to the reference value is ±1.7℃, and the threshold for abrupt changes in vibration signals relative to the reference value is ±2.4g. When any one of these signals at a single location exceeds the threshold, the system triggers an early warning. If all three signals are synchronously abnormal, it is determined to be a substantial pile defect. There is no need to calculate indirect parameters such as soil impermeability or leakage index; the defect type is determined directly based on the signal abrupt change characteristics. Defect types include leakage defects, diameter reduction defects, and broken pile defects. The identification of leakage defects, diameter reduction defects, and broken pile defects is explained in detail below: Leakage defect identification, specifically: When a combination of negative strain abrupt change, positive temperature abrupt change, and high-frequency vibration (in this embodiment, a frequency greater than or equal to 30 Hz is considered high-frequency) abrupt change occurs at a certain axial location, it is determined to be a pile leakage point. The principle is that at the leakage point, grout leaks out, causing a decrease in internal pile pressure and resulting in shrinkage strain. The hydration of the leaking grout causes a local temperature increase, and continuous grout leakage triggers high-frequency vibration. Axial leakage point identification uses an abnormal sensing unit group as its core, combined with the gradual change range of signals from adjacent units, controlling the identification accuracy within 0.5m. Simultaneously, the severity of the leakage point is distinguished based on the magnitude of the strain abrupt change amplitude: strain abrupt changes between 60 με and 118 με indicate a minor leakage point, while those above 118 με indicate a severe leakage point. After identifying a leakage point, the system immediately pushes an alert to the construction management platform, indicating the leakage depth and severity level. Construction personnel immediately perform re-grouting and sealing operations to plug the leakage location.

[0067] The identification of necking defects is as follows: When a combination of abrupt changes in strain, temperature, and low-frequency vibration (considered low-frequency in this embodiment, 0-30Hz) occurs at a certain axial location, it is determined to be pile diameter reduction. Insufficient grout filling at the diameter reduction location results in a smaller pile cross-section. External soil compression causes compressive strain in the pile, leading to localized grout accumulation, hydration, and temperature rise. Friction between the soil and pile generates low-frequency vibration. The axial diameter reduction identification accuracy is within 0.5m. The degree of diameter reduction is determined based on the amplitude of the strain mutation; a larger amplitude indicates a more severe loss of pile cross-section. After discovering the diameter reduction defect, construction personnel adjust the grouting pressure and flow rate, repeatedly spraying grout into the defective section to replenish the pile cross-section.

[0068] The identification of broken pile defects is as follows: A pile fracture is identified when a combination of strain step change, temperature step change, and vibration impact change occurs at a certain axial location. After the pile fractures, the upper and lower sections separate, and the strain and temperature signals exhibit a precipitous step change, with impact vibration generated at the moment of fracture. The identification accuracy for this type of defect can reach 0.25m, accurately distinguishing the depth of the upper and lower interfaces of the fractured pile. A broken pile is a major quality defect; the system triggers a level one warning, and all on-site construction is immediately halted. Drilling, grouting, and secondary pile construction are then carried out on the fractured section.

[0069] The early warning information flow and on-site handling: All defect early warning information includes defect type, precise depth, signal change amplitude, and handling suggestions, and is pushed to the on-site construction terminal and the back-end management platform in real time. The early warning information is accompanied by a timestamp and pile location number for easy record keeping. On-site personnel handle the situation according to the early warning level. Minor defects are rectified while construction continues, while major defects require immediate work stoppage for rectification. After rectification, the corresponding section of signal is continuously monitored, and normal construction can only resume after the signal is confirmed to have returned to the normal range.

[0070] Step 5: Full-cycle monitoring during the post-pile completion curing stage Step five specifically includes: After the jet grouting operation of the jet grouting pile is completed and the drill rod and grouting pipe are pulled out of the pile hole, the acquisition parameters of the demodulation equipment are adjusted. The acquisition frequency is reduced to one set every 10 minutes to adapt to the slow physical changes during the curing stage. The function of synchronous acquisition of three types of signals and curve display is retained to continuously record data such as pile strain and shrinkage, cement hydration cooling, and minor environmental vibrations.

[0071] The full-cycle continuous monitoring and maintenance monitoring period is strictly set at 28 days according to the specifications, covering the entire process of cement grout hydration, consolidation, and strength development. Each day, the signal curves of the entire pile length are checked in three key time periods: morning, noon, and evening, with particular attention paid to the pile top, pile bottom, and sections where previous defects have been rectified. During the maintenance phase, the main monitoring focuses on secondary defects such as pile shrinkage cracking, uneven settlement, and subsequent leakage. If local strain continues to increase negatively, it is determined that there is a risk of shrinkage cracking; if local temperature rises abnormally and is accompanied by vibration signals, it is determined that subsequent leakage has occurred. Upon detection of abnormalities, timely measures such as surface sealing and pressure grouting are taken.

[0072] After the 28-day maintenance period, real-time monitoring ceases, and the system automatically exports the original data, signal curves, defect warning records, and handling logs for the entire jet grouting pile cycle, classifying and archiving them by pile location number and construction time. This complete set of data can serve as the basis for pile integrity acceptance, eliminating the need for additional post-construction testing such as core drilling and low-strain analysis, thus achieving closed-loop management of the entire process from pre-embedding, construction monitoring, defect handling to maintenance acceptance.

[0073] After the equipment is reset and single-pile monitoring is completed, the connection between the optical cable and the demodulation equipment is disconnected, the cement slurry and soil attached to the surface of the optical cable are cleaned, and the appearance of the optical cable sheath and sensor unit is checked for damage. The optical cable is then recycled, tidied up, and stored in a reel for reuse at the next pile location. After the demodulation equipment completes data export, the factory basic parameters are restored, the equipment power is turned off, dust protection is implemented, and the system is ready for the next round of construction. The entire system can be reused in a cyclical manner, reducing monitoring costs.

[0074] Example 5: To verify the effectiveness of the method of the present invention, this embodiment conducted 8 experiments: Experiment 1: Pile location Z01 was selected, with a designed pile length of 8.6m and a designed pile diameter of 600mm. The strata, from top to bottom, consist of miscellaneous fill, silty soft soil, and silty clay, with a groundwater level depth of 3.2m. Following the established procedures, the fiber optic cable was customized, on-site marked, and the pile hole was drilled and the fiber optic cable was pre-embedded. The drilled hole diameter was 630mm, the actual drilled depth was 9.2m, and the sediment thickness at the pile bottom was 41mm. The total length of the fiber optic cable was 10.0m. The spacing between sensor units in the standard section was 1.0m, and the spacing between units in the 3.0m range from the pile top to the 2.0m range from the pile bottom was 0.5m. During the pre-embedding process, the maximum verticality deviation of the fiber optic cable was 0.27%, and the winch traction force was consistently maintained at 95N. The drill rod lifting speed during the jet grouting operation was 18cm / min, the grouting pressure was 22MPa, and the demodulation equipment scanning frequency was 160Hz throughout the construction process. Monitoring results: No abnormal signal changes occurred during the construction phase, and there were no defects such as leaks, diameter reduction, or broken piles; during the 28-day curing period, the pile strain, temperature, and vibration signals remained within the benchmark threshold range, the pile integrity was good, and no secondary problems such as cracking or leakage occurred in the later stages of curing.

[0075] Experiment 2: Pile location Z02 was selected, with a designed pile length of 11.2m and a designed pile diameter of 600mm. The strata consist of miscellaneous fill, silty soil, and medium-coarse sand layers, with a groundwater level depth of 2.8m. The borehole diameter was 630mm, the actual borehole depth was 11.8m, and the sediment thickness at the pile bottom was 38mm. The total length of the optical cable was 12.6m. The maximum vertical deviation of the optical cable during the entire pre-laying process was 0.25%, and the tightening torque of the borehole clamp was 18N. m. The jet grouting parameters were the same as in Implementation 1. At a pile depth of 4.7m, a strain mutation of 114με, a temperature mutation of 1.62℃, and a vibration mutation of 2.28g were detected, triggering a minor leak warning. Re-grouting and repair were promptly carried out on-site, and the signal at that location returned to the normal range after rectification. During subsequent construction and the 28-day curing period, the signals in other sections remained stable, and the overall pile quality met the standards.

[0076] Experiment 3: Pile location Z03 was selected, with a designed pile length of 15.7m and a designed pile diameter of 800mm. The strata contained alternating layers of soft and hard soil, and the groundwater level was at a depth of 4.1m. The borehole diameter was 830mm, the actual borehole depth was 16.3m, and the sediment thickness at the pile bottom was 43mm. The total length of the optical cable was 17.1m. During the lowering process, the verticality was checked in sections, with a maximum deviation of 0.28%. The jet grouting pressure was adjusted to 25MPa, and the drill rod lifting speed was 12cm / min. At a pile depth of 9.3m, a strain mutation of 126με, a temperature mutation of 1.75℃, and a vibration mutation of 2.36g were detected, indicating a moderate diameter reduction defect. The grouting flow rate and pressure were adjusted on-site for supplementary grouting, and the signal returned to normal after rectification. No new defects were found during the entire monitoring cycle, and all indicators of the pile remained stable during the curing phase.

[0077] Experiment 4: Pile location Z04 was selected, with a designed pile length of 18.1m and a designed pile diameter of 800mm. The soil composition is mainly silty clay and strongly weathered bedrock, with a groundwater level depth of 5.3m. The borehole diameter was 830mm, the actual borehole depth was 18.7m, and the sediment thickness at the pile bottom was 40mm. The total length of the optical cable was 19.5m, and the pre-laying operation proceeded smoothly with no significant deviation in the cable's orientation. During the jet grouting construction, a strain step change of 139με, a temperature step change of 1.81℃, and a vibration impact change of 2.42g occurred at a pile depth of 12.5m, indicating a shallow pile break. Work was immediately halted on-site for drilling and replacement pile treatment. After rectification, monitoring was conducted again, and the signal in the area returned to normal. Subsequent construction and maintenance phases showed no abnormalities.

[0078] Experiment 5: Pile location Z05 was selected, with a designed pile length of 9.4m and a designed pile diameter of 600mm. The soil stratum is primarily silty soft soil with high water content and a tendency for slight borehole wall collapse. The borehole diameter was 630mm, the actual borehole depth was 10.0m, and the sediment thickness at the pile bottom was 44mm. The total length of the optical cable was 10.8m, the lowering speed was 0.6m / min, and the traction force fluctuated between 92-97N throughout the process. The signal remained stable throughout the jet grouting construction, with only minor normal signal fluctuations at the stratum interface, without triggering any abnormal warnings. During the 28-day curing period, the pile temperature gradually and naturally decreased with cement hydration, and the strain slowly contracted without cracking or leakage; the pile integrity was deemed satisfactory.

[0079] Experiment 6: Pile number Z06 was selected, with a designed pile length of 22.3m and a designed pile diameter of 800mm, making it the longest pile on the site. The strata are multi-layered, including miscellaneous fill, silty soil, silty clay, medium-coarse sand, and strongly weathered rock, with a groundwater level at a depth of 3.6m. The borehole diameter was 830mm, the actual borehole depth was 22.9m, and the sediment thickness at the pile bottom was 42mm. The total length of the optical cable was 23.7m. Due to the large pile length, the frequency of segmented testing increased, and the maximum verticality deviation of the optical cable was 0.29%. The jet grouting construction used a grouting pressure of 25MPa and a lifting speed of 12cm / min. Multiple small signal fluctuations were detected in the 2.1m section at the top of the pile, with a minor leak warning triggered at a depth of 1.8m. After local re-grouting, the hidden danger was eliminated. After the completion of the entire pile construction, all monitoring data remained stable during the curing phase.

[0080] Experiment 7: Pile location Z07 was selected, with a designed pile length of 13.5m and a designed pile diameter of 600mm. The soil has a high proportion of medium-coarse sand and strong permeability. The borehole diameter was 630mm, the actual borehole depth was 14.1m, and the sediment thickness at the pile bottom was 39mm. The total length of the optical cable was 14.9m, and the pre-embedding and line connection were normal. During the jet grouting construction, a diameter reduction characteristic signal appeared at a pile depth of 6.8m, with a strain mutation of 121με, a temperature mutation of 1.69℃, and a vibration mutation of 2.31g. After re-grouting treatment, the defect was eliminated, and there was no recurrence during the entire cycle of monitoring. All performance characteristics of the pile met the design requirements.

[0081] Experiment 8: Pile location Z08 was selected, with a designed pile length of 16.9m and a designed pile diameter of 800mm. The strata contained multiple transitional zones between soft and hard surfaces, resulting in significant construction disturbance. The borehole diameter was 830mm, the actual drilling depth was 17.5m, and the sediment thickness at the pile bottom was 41mm. The total length of the optical cable was 18.3m, and its lowering attitude was well controlled. Signals were normal in the early stages of the jet grouting construction. A broken pile characteristic signal was detected at a pile depth of 14.2m, prompting a timely halt to work and rectification. Monitoring continued after the replacement pile was completed, and no secondary defects appeared in the pile during the curing phase.

[0082] This embodiment completed a full-cycle monitoring test of jet grouting piles with different pile lengths, diameters, and geological conditions. It covered a variety of typical working conditions, including conventional soft soil, sand, mixed soft and hard strata, and weathered rock. The test scenarios closely matched the actual construction status of geotechnical engineering.

[0083] Overall, the defect identification method for jet grouting piles based on distributed fiber optic sensing technology is stable. The pre-embedded composite optical cables and various types of fiber optic grating sensing units did not exhibit damage, signal interruption, or wavelength drift under complex conditions such as high-pressure grouting, ground friction, and soil deformation. The hardware reliability of the sensing system meets the requirements for long-term field use. Key indicators such as verticality, traction force, borehole fixing torque, and pile bottom sediment of all piles during the optical cable pre-embedding stage were controlled within the preset allowable range. The pre-embedding process is standardized and reproducible, ensuring coordinated deformation of the sensing units and the pile body and accurate data acquisition. During monitoring, the system can quickly identify three core defects—leakage points, diameter reduction, and pile breakage—based on direct abnormal changes in strain, temperature, and vibration signals, without needing to calculate indirect parameters such as soil impermeability and leakage index, significantly simplifying the data processing flow. The defect identification response speed is fast, and the defect identification accuracy is controlled within the design range, demonstrating stable identification capabilities in short piles, long piles, and different strata. In strata prone to defects, such as soft soil and highly permeable sand layers, the system can detect potential problems in advance and trigger early warnings, enabling immediate on-site rectification and effectively eliminating construction quality issues during the pile formation stage. For challenging conditions like ultra-long piles and mixed soft-hard strata, where pile breakage is common, the system can accurately determine the location and type of defects. Monitoring data from a complete 28-day curing cycle demonstrates that this technology not only enables dynamic control of the construction process but also continuously monitors pile hydration, shrinkage, and settlement, promptly identifying secondary defects such as cracking and leakage, forming a comprehensive quality control system from pre-embedding, construction monitoring, defect rectification to curing acceptance. Compared to traditional post-pile core sampling and low-strain testing methods, this invention achieves real-time online monitoring, significantly improving detection efficiency while reducing pile damage caused by destructive testing. Compared to traditional multi-parameter coupled calculation monitoring methods, this invention has a simpler logic and stronger resistance to environmental interference.

[0084] Based on all test data and field performance, this technology is suitable for various foundation conditions, and its monitoring accuracy, stability, and practicality meet the needs of engineering applications, making it widely applicable.

[0085] Example 6: Please see Figure 3 As shown, the present invention also provides an electronic device 100 for a jet grouting pile defect identification method based on distributed optical fiber sensing technology; the electronic device 100 includes a memory 101, at least one processor 102, a computer program 103 stored in the memory 101 and executable on the at least one processor 102, and at least one communication bus 104.

[0086] The memory 101 can be used to store the computer program 103. The processor 102 implements the steps of the jet grouting pile defect identification method based on distributed optical fiber sensing technology described in Embodiment 1 by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101. The memory 101 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the electronic device 100 (such as audio data), etc. In addition, the memory 101 may include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0087] The at least one processor 102 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 102 may be a microprocessor or any conventional processor. The processor 102 is the control center of the electronic device 100, connecting various parts of the electronic device 100 via various interfaces and lines.

[0088] The memory 101 in the electronic device 100 stores multiple instructions to implement a jet grouting pile defect identification method based on distributed optical fiber sensing technology, and the processor 102 can execute the multiple instructions to achieve the following: During the construction of jet grouting piles, the wavelength signal of the distributed optical fiber sensing unit is acquired; The wavelength change is obtained based on the wavelength signal from the distributed optical fiber sensing unit. The wavelength change is converted into strain data, temperature data, and vibration data; By binding strain data, temperature data, and vibration data with the axial position of the distributed fiber optic sensing unit, strain curves, temperature curves, and vibration curves are obtained. Acquire real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves; The real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve are compared with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. Based on the characteristics of abnormal abrupt changes in strain, temperature, and vibration data, the defect type of the jet grouting pile is determined.

[0089] Example 7: If the modules / units integrated in the electronic device 100 are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0090] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0091] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0092] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0093] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for defect identification of jet grouting piles based on distributed optical fiber sensing technology, characterized in that, Includes the following steps: During the construction of jet grouting piles, the wavelength signal of the distributed optical fiber sensing unit is acquired; The wavelength change is obtained based on the wavelength signal from the distributed optical fiber sensing unit. The wavelength change is converted into strain data, temperature data, and vibration data; By binding strain data, temperature data, and vibration data with the axial position of the distributed fiber optic sensing unit, strain curves, temperature curves, and vibration curves are obtained. Acquire real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves; The real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve are compared with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. Based on the characteristics of abnormal abrupt changes in strain, temperature, and vibration data, the defect type of the jet grouting pile is determined.

2. The method for identifying defects in jet grouting piles based on distributed optical fiber sensing technology according to claim 1, characterized in that, The distributed optical fiber sensing unit is encapsulated in an integrated stainless steel sealed package.

3. The method for defect identification of jet grouting piles based on distributed optical fiber sensing technology according to claim 1, characterized in that, The threshold for determining abnormal mutations is determined based on formation conditions, construction techniques, and preliminary test data.

4. The method for defect identification of jet grouting piles based on distributed optical fiber sensing technology according to claim 1, characterized in that, The defect type of the jet grouting pile is determined based on the characteristics of abnormal abrupt changes in strain, temperature, and vibration data, specifically as follows: If the strain data shows a negative abrupt change, the temperature data shows a positive abrupt change, and the vibration data shows a high-frequency abrupt change, then the jet grouting pile is determined to be a leak point defect. If the strain data shows a positive abrupt change, the temperature data shows a positive abrupt change, and the vibration data shows a low-frequency abrupt change, then the jet grouting pile is determined to have a diameter reduction defect. If the strain data shows a step change, the temperature data shows a step change, and the vibration data shows an impact change, then the jet grouting pile is determined to be a broken pile defect.

5. The method for defect identification of jet grouting piles based on distributed optical fiber sensing technology according to claim 4, characterized in that, If the jet grouting pile is determined to have a leak, the construction workers will immediately carry out re-grouting and patching operations to seal the leak.

6. The method for identifying defects in jet grouting piles based on distributed optical fiber sensing technology according to claim 4, characterized in that, If the jet grouting pile is determined to have a diameter reduction defect, the construction personnel will adjust the grouting pressure and grout flow rate, and repeat the grouting in the defective section to make up for the cross-section of the pile.

7. The method for identifying defects in jet grouting piles based on distributed optical fiber sensing technology according to claim 4, characterized in that, If a jet grouting pile is determined to have a broken pile defect, all construction should be stopped immediately.

8. A defect identification system for jet grouting piles based on distributed optical fiber sensing technology, characterized in that, include: The data acquisition module is used to acquire the wavelength signal of the distributed optical fiber sensing unit during the jet grouting pile construction process. The wavelength change determination module is used to obtain the wavelength change based on the wavelength signal from the distributed optical fiber sensing unit. The conversion module is used to convert wavelength changes into strain data, temperature data, and vibration data. The curve plotting module is used to bind strain data, temperature data, and vibration data with the axial position of the distributed fiber optic sensing unit to obtain strain curves, temperature curves, and vibration curves. Acquire real-time strain data, real-time temperature data, and real-time vibration data from strain curves, temperature curves, and vibration curves; The comparison module is used to compare the real-time strain data, real-time temperature data, and real-time vibration data in the strain curve, temperature curve, and vibration curve with the pre-set thresholds for judging abnormal changes in strain data, temperature data, and vibration data, so as to obtain the characteristics of abnormal changes in strain data, temperature data, and vibration data. The defect type determination module is used to determine the defect type of the jet grouting pile based on the characteristics of abnormal changes in strain data, temperature data, and vibration data.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the jet grouting pile defect identification method based on distributed optical fiber sensing technology as described in any one of claims 1 to 7.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the jet grouting pile defect identification method based on distributed optical fiber sensing technology as described in any one of claims 1 to 7.

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