Cast-in-place pile pouring process quality detection method capable of sensing ERT on inner side and outer side

Abstract

The invention discloses a cast-in-place pile pouring process quality detection method capable of sensing ERT on the inner side and the outer side. The cast-in-place pile pouring process quality detection method comprises the steps that conductivity information of the inner side and the outer side of a cast-in-place pile is collected through an electrical resistance tomography electrode array arranged at the bottom of a cast-in-place pile feeding guide pipe; the two-dimensional position information of the electrical resistance tomography electrode array in the pile hole in the horizontal direction is positioned through an ultrasonic transducer array arranged at the bottom of the feeding guide pipe; the depth information of the electrical resistance tomography electrode array is acquired through an incremental encoder and a roller which move along with the feeding guide pipe in the vertical direction; transmitting the obtained conductivity information, the two-dimensional position information and the depth information to a computer imaging system to obtain a three-dimensional conductivity distribution image of the cast-in-place pile, and analyzing the obtained image to realize quality detection of the cast-in-place pile. Total cross-section imaging of concrete and a reinforcement cage can be achieved, and the positions and sizes of karst caves and collapse possibly existing in the pile hole wall can be accurately measured.

Description

Technical Field

[0001] The present invention relates to the field of bored pile casting engineering and electrical resistance tomography technology, and in particular to a method for detecting the quality of bored pile casting process by sensing ERT from both inside and outside sides. Background Art

[0002] Electrical Resistance Tomography (ERT) technology is a type of process tomography technology. Electrical resistance tomography is a very promising two-phase flow / multiphase flow detection technology that can realize the visual measurement of multiphase flow material parameters inside closed pipelines or container equipment, and has broad application prospects. Its physical basis is that different media have different electrical conductivities. Therefore, by judging the conductivity distribution of objects in the sensitive field, the distribution of the medium in the field can be inferred. ERT measures the conductivity distribution of the medium in the imaging area by loading alternating current on two electrodes in the array electrode and measuring the potential of other electrodes. It is widely used in the characteristic value measurement of gas-liquid two-phase flow or solid-liquid two-phase flow, and has the characteristics of large amount of information, non-invasiveness, low cost, and good safety. It can realize online or offline imaging of the field distribution of the object being measured, and is a new detection method. The ERT system can be divided into three main parts: (1) Array sensor: Utilizing spatially sensitive array electrode sensors, the excitation / measurement mode is used to transform the object field distribution information into electrical signals, that is, to obtain the measured value of the positive problem based on the actual distribution of the object field. (2) Data acquisition and processing: The weak output voltage signal of the measuring electrode pair is collected, and after passing through the signal conditioning circuit, the acquired data is sent to the host computer. (3) Image reconstruction and data analysis: Using the acquired data acquisition signal, an appropriate image reconstruction algorithm is used to reconstruct the medium distribution inside the measured object field, and further extract the characteristic information of the measured object field.

[0003] Currently, most bored pile inspection methods (low-strain reflection wave method, acoustic transmission method, high-strain method, static load test, and borehole coring) perform measurements after the concrete has cured. This makes it impossible to measure problems during the pouring process in real time, resulting in extremely high repair costs for problematic piles. Publication No. CN104099956A estimates the density of the pouring medium using the pressure difference between pressure sensors arranged along the height direction. This method indirectly determines the integrity of the concrete curing process online by continuously measuring the density stability, but is susceptible to the effects of concrete flow. Publication No. CN114108713B proposes real-time imaging of the bored pile pouring process using electrical resistance tomography (ERT). However, due to the limitations of conventional ERT methods, which only image the interior of the pipe, the proposed method, influenced by the bored pile reinforcement cage, can only image a limited circular area within the reinforcement cage (less than one-quarter of the pile hole cross-sectional area), failing to fully inspect the pile hole cross-section. Therefore, improvements are needed to apply ERT technology to three-dimensional imaging in bored pile construction. Summary of the Invention

[0004] 1. Technical problems to be solved: To address the above-mentioned technical issues, the present invention provides a method for inspecting the quality of bored pile casting using internal and external ERT sensing. This method improves upon existing real-time imaging of the bored pile casting process using electrical resistance tomography (ERT). The method not only images the interior of the sensor tube but also the exterior of the ERT electrode array tube. The diameter of the imaging area is larger than the diameter of the electrode array tube, thereby enabling full-cross-sectional two-dimensional imaging of the entire pile bore area when the electrode array tube is smaller than the reinforcement cage. Furthermore, the present invention measures the distance traveled by the concrete feed conduit by installing a guide wheel and an incremental encoder on the conduit, thereby measuring the depth of the ERT electrode array tube. This allows the location of defects detected by imaging to be determined. A complete three-dimensional image of the bored pile casting process is obtained based on the two-dimensional pile bore imaging and the depth of the electrode array tube.

[0005] 2. Technical solution: A method for inspecting the quality of a bored pile casting process using internal and external ERT sensing is characterized by: collecting conductivity information both inside and outside the bored pile using an electrical resistance tomography (ERT) electrode array disposed at the bottom of the bored pile feed conduit; obtaining two-dimensional horizontal position information of the electrical resistance tomography (ERT) electrode array within the pile hole using an ultrasonic transducer array disposed at the bottom of the feed conduit; collecting depth information of the electrical resistance tomography (ERT) electrode array using an incremental encoder and a roller that move vertically with the feed conduit; transmitting the acquired conductivity information, two-dimensional position information, and depth information to a computer imaging system to obtain a three-dimensional conductivity distribution image of the bored pile; and analyzing the acquired three-dimensional conductivity distribution image to inspect the quality of the bored pile casting process.

[0006] Furthermore, the data acquisition device implemented therein includes a feed conduit, a measuring tube, an incremental encoder and a roller; the inner diameter of the measuring tube made of insulating material is larger than that of the feed conduit and smaller than that of the steel cage, and is immersed in the measured medium, i.e., the flowing concrete slurry, during measurement; the measuring tube is suspended to the bottom outlet of the feed conduit through an adjustable device; each electrode in the resistance tomography electrode array is embedded in the tube wall of the measuring tube at the same height, and the electrode surface contacts the measured medium inside and outside the measuring tube, forming a ring-shaped electrode array; the multiple ultrasonic transducers in the ultrasonic transducer array are evenly distributed at the same height on the outer wall of the measuring tube, and the position of the measuring tube in the pile hole is obtained by collecting the echo time during data acquisition, thereby obtaining the horizontal two-dimensional position information of the resistance tomography electrode array at this time; the incremental encoder and the roller are installed on the top of the feed conduit, and when the feed conduit is lifted, the roller is driven to rotate, and the incremental encoder measures the rotation angle of the roller to measure the depth of the measuring tube.

[0007] Furthermore, the data processing and imaging device implemented therein includes a computer pre-installed with an ERT two-dimensional image reconstruction algorithm and a three-dimensional image stitching algorithm; the ultrasonic transducer array and the electrical resistance tomography electrode array transmit the collected horizontal two-dimensional position information and conductivity information to the computer via a wireless transmission module to realize the acquisition of two-dimensional images of the cast-in-place piles; the incremental encoder transmits the collected depth information to the computer, matches the depth information with the two-dimensional image, and thereby realizes the acquisition of horizontal and vertical three-dimensional images of the cast-in-place piles.

[0008] Furthermore, the resistance tomography electrode array adopts an adjacent excitation measurement mode, applying an excitation current to two adjacent electrodes and measuring the voltage on other electrodes in the array; measuring the voltage of other electrodes under the excitation of all adjacent electrodes in sequence; and obtaining conductivity information for image reconstruction by measuring the voltage of other electrodes under the excitation of different electrode pairs on the sensitive electrode array.

[0009] Furthermore, the adjustable device is a chain device; it includes multiple chains, and the feeding conduit and the measuring tube are coaxially connected by adjusting the chains, while ensuring that the concrete slurry flowing out of the feeding conduit can flow smoothly to the outside of the measuring tube.

[0010] Furthermore, the measurement and control circuits of the electrical resistance tomography electrode array and the ultrasonic transducer array are integrated into a measurement integrated circuit, which is arranged in the inner wall of the measuring tube; the measurement integrated circuit also integrates a battery and a wireless transmission module; the wireless transmission module is a wireless transmission module based on the LoRa protocol; the incremental encoder uploads information to the computer via 485 communication.

[0011] Further, the following steps are included: Step 1: Install the measuring tube to the bottom outlet of the feed conduit, and install the incremental encoder and roller to the inlet of the feed conduit; calibrate the initial depth of the measuring tube, the center of the measuring tube, and the vertical distance between the electrical resistance tomography electrode array and the ultrasonic transducer array; Step 2: During the concrete pouring process, based on a preset acquisition cycle, the RRT electrode array excites the electrodes to obtain conductivity information at that moment. The ultrasonic transducer array emits ultrasonic waves to the pile hole wall to obtain the echo time to obtain the array position at that moment. The horizontal coordinate of the RRT electrode array is obtained by combining the vertical distance between the two arrays. The depth information of the incremental encoder is obtained to obtain the vertical coordinate of the sensitive field. Step 3: The computer acquires the conductivity information at each acquisition moment and reconstructs a two-dimensional conductivity image of the inside and outside of the pipe in the plane where the electrical resistance tomography electrode array is located at that moment using the ERT two-dimensional image reconstruction algorithm. The position of the ERT image in the pile hole is adjusted based on the horizontal coordinate information measured by ultrasound. The two-dimensional electrical resistance tomography images at different depths are spliced ​​together to form a quasi-3D conductivity distribution image. Step 4: Based on the reconstructed conductivity distribution image, real-time detection is performed to determine whether there are one or more quality issues in the pouring process, including water seepage, pile hole wall collapse, uneven concrete slurry distribution, steel cage position offset, missing steel cage, or other quality issues in the construction process.

[0012] Furthermore, the body of the measuring cylinder is made of an electrically insulating composite resin material with a high elastic modulus, and the cylinder body does not deform when subjected to impact.

[0013] 3.Beneficial effects: (1) This method proposes a method for detecting the quality of the cast-in-place pile casting process using ERT, which can sense both inside and outside the pile, and solve the problem that the measuring tube cannot cover the entire measuring area. In the existing technology, the ERT sensor with only one-side sensing inward is unable to image the entire cross section of the cast-in-place pile due to interference from the steel cage and the problem that the pipe may get stuck on the pile hole wall due to its large size. This method can not only image the entire cross section of the concrete and steel cage, but also accurately measure the location and size of possible cavities and collapses in the pile hole wall.

[0014] (2) This method proposes a method for detecting the quality of bored pile casting process by sensing ERT on both the inside and outside sides. It performs real-time conductivity imaging of the casting center position, which can detect problems that occur during the casting process in real time, discover problems in time and facilitate handling, and avoid the huge economic costs and serious impact on the project progress caused by measuring problems after solidification and then dealing with broken piles.

[0015] (3) This method proposes a method for detecting the quality of bored pile casting process with internal and external double-sided sensing ERT. By using electrical resistance tomography with internal and external double-sided sensing and combining it with the three-dimensional position data measured in the pile hole, a complete three-dimensional image is provided for each pile foundation, which greatly improves the casting quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the electrical resistance tomography electrode array involved in the present method for collecting sensitive field information inside and outside the tube; Figure 2 is an overall schematic diagram of the data acquisition device involved in this method; Figure 3 A cross-sectional view of the data acquisition device at position AA in this method; Figure 4 is a cross-sectional view of the BB position of the data acquisition device in this method; Figure 5 The overall block diagram of the bored pile pouring process quality detection system for realizing the internal and external dual-side sensing ERT of this method; Figure 6 The figure is the simulation result of the verification example.

[0017] Explanation of reference numerals: 1 hopper; 2 incremental encoder and roller; 3 feed conduit; 4 pile hole; 5 reinforcement cage; 6 water; 7 muddy water; 8 flowing concrete; 9 adjustable device; 10 measurement circuit and battery; 11 electrical resistance tomography electrode array; 12 measurement tube; 13 ultrasonic transducer. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below with reference to the accompanying drawings.

[0019] As attached Figure 2 To the attached Figure 5 As shown, a method for inspecting the quality of a bored pile casting process using internal and external ERT sensing is described, characterized in that: an electrical resistance tomography electrode array 11 disposed at the bottom of a bored pile feed conduit 3 collects conductivity information both inside and outside the conduit; an array of ultrasonic transducers 13 disposed at the bottom of the feed conduit locates two-dimensional position information of the electrical resistance tomography electrode array in the horizontal direction within the pile hole; an incremental encoder and a roller 2 that move vertically with the feed conduit collect depth information of the electrical resistance tomography electrode array; the acquired conductivity information, two-dimensional position information, and depth information are transmitted to a computer imaging system to obtain a three-dimensional conductivity distribution image of the bored pile; and the acquired three-dimensional conductivity distribution image is analyzed to inspect the quality of the bored pile casting process.

[0020] Furthermore, the data acquisition device implemented therein includes a feed conduit 3, a measuring tube 12, an incremental encoder and a roller 2; the inner diameter of the measuring tube made of insulating material is larger than that of the feed conduit and smaller than that of the steel cage, and is immersed in the measured medium, i.e., the flowing concrete slurry, during measurement; the measuring tube is suspended to the bottom outlet of the feed conduit through an adjustable device; each electrode in the resistance tomography electrode array is embedded in the tube wall of the measuring tube at the same height, and the electrode surface contacts the measured medium inside and outside the measuring tube, forming a ring-shaped electrode array; the multiple ultrasonic transducers in the ultrasonic transducer array are evenly distributed to the same height of the outer wall of the measuring tube, and the position of the measuring tube in the pile hole is obtained by collecting the echo time during data acquisition, thereby obtaining the horizontal two-dimensional position information of the resistance tomography electrode array at this time; the incremental encoder and the roller are installed on the top of the feed conduit, and when the feed conduit is lifted, the roller is driven to rotate, and the incremental encoder measures the rotation angle of the roller to measure the depth of the measuring tube.

[0021] Furthermore, the data processing and imaging device implemented therein includes a computer pre-installed with an ERT two-dimensional image reconstruction algorithm and a three-dimensional image stitching algorithm; the ultrasonic transducer array and the electrical resistance tomography electrode array transmit the collected horizontal two-dimensional position information and conductivity information to the computer via a wireless transmission module to realize the acquisition of two-dimensional images of the cast-in-place piles; the incremental encoder transmits the collected depth information to the computer, matches the depth information with the two-dimensional image, and thereby realizes the acquisition of horizontal and vertical three-dimensional images of the cast-in-place piles.

[0022] Furthermore, the resistance tomography electrode array adopts an adjacent excitation measurement mode, applying an excitation current to two adjacent electrodes and measuring the voltage on other electrodes in the array; measuring the voltage of other electrodes under the excitation of all adjacent electrodes in sequence; and obtaining conductivity information for image reconstruction by measuring the voltage of other electrodes under the excitation of different electrode pairs on the sensitive electrode array.

[0023] Furthermore, the adjustable device 9 is a chain device; it includes multiple chains, and the feeding conduit and the measuring tube are coaxially connected by adjusting the chains, while ensuring that the concrete slurry flowing out of the feeding conduit can flow smoothly to the outside of the measuring tube.

[0024] Furthermore, the measurement and control circuits of the electrical resistance tomography electrode array and the ultrasonic transducer array are integrated into a measurement integrated circuit 10, which is arranged in the inner wall of the measuring tube; the measurement integrated circuit also integrates a battery and a wireless transmission module; the wireless transmission module is a wireless transmission module based on the LoRa protocol; the incremental encoder uploads information to the computer via 485 communication.

[0025] Further, the following steps are included: Step 1: Install the measuring tube to the bottom outlet of the feed conduit, and install the incremental encoder and roller to the inlet of the feed conduit; calibrate the initial depth of the measuring tube, the center of the measuring tube, and the vertical distance between the electrical resistance tomography electrode array and the ultrasonic transducer array; Step 2: During the concrete pouring process, based on a preset acquisition cycle, the RRT electrode array excites the electrodes to obtain conductivity information at that moment. The ultrasonic transducer array emits ultrasonic waves to the pile hole wall to obtain the echo time to obtain the array position at that moment. The horizontal coordinate of the RRT electrode array is obtained by combining the vertical distance between the two arrays. The depth information of the incremental encoder is obtained to obtain the vertical coordinate of the sensitive field. Step 3: The computer acquires the conductivity information at each acquisition moment and reconstructs a two-dimensional conductivity image of the inside and outside of the pipe in the plane where the electrical resistance tomography electrode array is located at that moment using the ERT two-dimensional image reconstruction algorithm. The position of the ERT image in the pile hole is adjusted based on the horizontal coordinate information measured by ultrasound. The two-dimensional electrical resistance tomography images at different depths are spliced ​​together to form a quasi-3D conductivity distribution image. Step 4: Based on the reconstructed conductivity distribution image, real-time detection is performed to determine whether there are one or more quality issues in the pouring process, including water seepage, pile hole wall collapse, uneven concrete slurry distribution, steel cage position offset, missing steel cage, or other quality issues in the construction process.

[0026] Furthermore, the body of the measuring cylinder is made of an electrically insulating composite resin material with a high elastic modulus, and the cylinder body does not deform when subjected to impact. Specific embodiment: The pouring process of the cast-in-place pile involved in this method is as follows Figure 2 As shown, a rebar cage 5 is placed in the pile hole 4, and then a feed conduit 3 is inserted. The bottom of the feed conduit 3 is equipped with a feed conduit port for discharge, and the top is equipped with a hopper 1 for feeding. During construction, the feed conduit 3 is inserted into the rebar cage 5 and initially stopped at a certain distance from the pile hole bottom. Material is then poured through the hopper 1, forming multiple fluid layers from bottom to top at the bottom of the pile hole: flowing concrete 8, slurry 7, and water 6. After the initial pour, feeding and pouring continue, and the feed conduit 3 is slowly raised, gradually completing the concrete pouring of the entire hole. During this process, this solution utilizes a dual-sided electrical resistance tomography method with inward and outward sensing, along with its quality inspection system for the cast-in-place pile casting process, to continuously image the concrete during the cast-in-place pile casting process.

[0028] This embodiment images the conductivity distribution within the pile hole during cast-in-place pile construction, enabling cross-sectional imaging at different depths. The resulting three-dimensional images can be used to identify broken piles caused by rebar cages, water seepage, landslides, and voids based on conductivity anomalies. Furthermore, the location of pile quality issues can be accurately determined, allowing for timely remediation.

[0029] In this embodiment, the electrical resistance tomography electrode array includes 16 electrodes. Conventional techniques for circular tube electrical resistance tomography (ERT) imaging typically use an inward sensing imaging system. The sensor electrode array is only electrically connected to the medium within the tube, imaging only the conductivity distribution of the medium within the tube. The electrode array is insulated from the area outside the tube. However, in the present invention's inward- and outward-sensing ERT imaging method, both the inside and outside of the tube are imaged, and the electrodes are electrically connected to both the inside and outside of the tube, as shown in the attached diagram. Figure 1 As shown, during the detection process, an AC excitation current is applied to adjacent electrodes 1 and 16, and the potential difference V between all adjacent electrodes 2-3, 3-4, ..., 14-15 is measured in sequence; then an AC excitation current is applied to electrodes 1 and 2, and the potential differences between electrodes 3-4, 4-5, ..., 15-16 are measured in sequence, and so on. Finally, an AC excitation current is applied to electrodes 15 and 16, and the potential differences between electrodes 1-2, 2-3, ..., 13-14 are measured in sequence, thereby completing the acquisition of all data for one frame of image. Figure 1 The distribution of equipotential lines inside and outside the sensor pipe under the excitation of electrodes 1 and 16 is shown. Measuring the potential difference V between any adjacent electrodes reflects the conductivity distribution on both sides of the pipe. This ultimately enables a dual-sided electrical resistance tomography method with inward and outward sensing, significantly increasing the imaging range.

[0030] In this method, the electrical resistance tomography (ERT) electrode array is embedded in the wall of a measuring tube. The conductive electrodes directly contact the measured medium on both sides of the tube, including concrete, water, collapsed soil, and reinforced steel cages. The measuring tube is made of an electrically insulating, high-strength composite resin material, and its hardness is required to ensure it remains resistant to deformation under impact.

[0031] In this embodiment, four transducers are usually selected and evenly distributed on the outer wall of the measuring tube, with a known distance between them and the electrodes.

[0032] Verification example: This demonstration uses the finite element method to construct an electrical resistance tomography (ERT) model for inward and outward dual-image sensing. The frontier advancing method achieves high-precision adaptive discretization of the geometric domain. Using a pioneering annular ERT system with inward and outward dual-sensing architecture, 16 insulated electrodes are equally spaced (with a strict 1:1 ratio of electrode width to gap width) on the outer wall of the pile hole (R = 10 cm radius) and the inner wall of the measuring tube (r = 6 cm radius). This enables simultaneous analysis of the conductivity distribution within the measuring tube (0 < ρ < 6 cm) and in the annular region outside the measuring tube (6 cm < ρ < 10 cm). This system, applied to the quality monitoring of cast-in-place pile concrete placement, employs an improved Newton-Raphson iterative algorithm to detect uneven changes in cross-sectional conductivity distribution in real time and accurately identify defects such as concrete segregation and voids. Figure 6 The simulation experiment results show that the system can accurately identify complex flow patterns and form a complete "sensing-imaging-evaluation" quality control closed loop. It can replace the traditional drilling and coring method to reduce detection costs and provide a reliable real-time monitoring solution for concrete pouring in civil engineering.

[0033] Although the present invention has been disclosed above in terms of preferred embodiments, they are not intended to limit the present invention. Anyone skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined by the claims of this application.

Claims

1. A method for detecting the quality of a bored pile during pouring with internal and external ERT sensing, characterized by: An electrical resistance tomography (ERT) electrode array, located at the bottom of the bored pile feed conduit, collects conductivity information both inside and outside the conduit. An ultrasonic transducer array, also located at the bottom of the feed conduit, acquires two-dimensional horizontal position information of the ERT electrode array within the pile hole. An incremental encoder and roller, moving vertically with the feed conduit, acquire depth information from the ERT electrode array. The acquired conductivity information, two-dimensional position information, and depth information are transmitted to a computer imaging system to obtain a three-dimensional conductivity distribution image of the bored pile. Analysis of the acquired three-dimensional conductivity distribution image allows quality inspection of the bored pile casting process.

2. The method for detecting the quality of a bored pile during pouring with ERT sensing on both the inside and outside sides according to claim 1 is characterized by: The data acquisition device implemented therein includes a feed conduit, a measuring tube, an incremental encoder and a roller; the inner diameter of the measuring tube made of insulating material is larger than that of the feed conduit and smaller than that of the steel cage, and is immersed in the measured medium, i.e., the flowing concrete slurry, during measurement; the measuring tube is suspended to the bottom outlet of the feed conduit through an adjustable device; each electrode in the resistance tomography electrode array is embedded in the tube wall of the measuring tube at the same height, and the electrode surface contacts the measured medium inside and outside the measuring tube, forming a ring-shaped electrode array; multiple ultrasonic transducers in the ultrasonic transducer array are evenly distributed at the same height on the outer wall of the measuring tube. During data acquisition, the position of the measuring tube in the pile hole is obtained by collecting the echo time, and then the horizontal two-dimensional position information of the resistance tomography electrode array at this time is obtained; the incremental encoder and roller are installed on the top of the feed conduit. When the feed conduit is lifted, the roller is driven to rotate, and the incremental encoder measures the rotation angle of the roller to measure the depth of the measuring tube.

3. The method for detecting the quality of a bored pile during pouring with ERT sensing on both the inside and outside sides according to claim 2 is characterized by: The data processing and imaging device implemented therein includes a computer pre-installed with an ERT two-dimensional image reconstruction algorithm and a three-dimensional image stitching algorithm; the ultrasonic transducer array and the electrical resistance tomography electrode array transmit the collected horizontal two-dimensional position information and conductivity information to the computer via a wireless transmission module to realize the collection of two-dimensional images of the cast-in-place piles; the incremental encoder transmits the collected depth information to the computer, matches the depth information with the two-dimensional image, and thereby realizes the collection of horizontal and vertical three-dimensional images of the cast-in-place piles.

4. The method for detecting the quality of a bored pile during pouring with ERT sensing on both the inside and outside sides according to claim 2 is characterized by: The electrical resistance tomography electrode array adopts an adjacent excitation measurement mode, applying an excitation current to two adjacent electrodes and measuring the voltages on other electrodes in the array; the voltages of other electrodes under the excitation of all adjacent electrodes are measured in sequence; and by measuring the voltages of other electrodes under the excitation of different electrode pairs on the sensitive electrode array, conductivity information for image reconstruction is obtained.

5. The method for detecting the quality of a bored pile during pouring with ERT sensing on both the inside and outside sides according to claim 2 is characterized by: The adjustable device is a chain device; it includes multiple chains, and the chain is adjusted to achieve coaxial connection between the feed conduit and the measuring tube, while ensuring that the concrete slurry flowing out of the feed conduit can flow smoothly to the outside of the measuring tube.

6. The method for detecting the quality of a bored pile during pouring with ERT sensing on both the inside and outside sides according to claim 2 is characterized by: The measurement and control circuits of the electrical resistance tomography electrode array and ultrasonic transducer array are integrated into a measurement integrated circuit, which is arranged in the inner wall of the measuring tube. The measurement integrated circuit also integrates a battery and a wireless transmission module; the wireless transmission module is a wireless transmission module based on the LoRa protocol; the incremental encoder uploads information to the computer via 485 communication.

7. The method for detecting the quality of a bored pile during pouring with ERT sensing on both the inside and outside sides according to claim 2 is characterized by: The following steps are involved: Step 1: Install the measuring tube to the bottom outlet of the feed conduit, and install the incremental encoder and roller to the inlet of the feed conduit; calibrate the initial depth of the measuring tube, the center of the measuring tube, and the vertical distance between the electrical resistance tomography electrode array and the ultrasonic transducer array; Step 2: During the concrete pouring process, based on a preset acquisition cycle, the RRT electrode array excites the electrodes to obtain conductivity information at that moment. The ultrasonic transducer array emits ultrasonic waves to the pile hole wall to obtain the echo time to obtain the array position at that moment. The horizontal coordinate of the RRT electrode array is obtained by combining the vertical distance between the two arrays. The depth information of the incremental encoder is obtained to obtain the vertical coordinate of the sensitive field. Step 3: The computer acquires the conductivity information at each acquisition moment and reconstructs a two-dimensional conductivity image of the inside and outside of the pipe in the plane where the electrical resistance tomography electrode array is located at that moment using the ERT two-dimensional image reconstruction algorithm. The position of the ERT image in the pile hole is adjusted based on the horizontal coordinate information measured by ultrasound. The two-dimensional electrical resistance tomography images at different depths are spliced ​​together to form a quasi-3D conductivity distribution image. Step 4: Based on the reconstructed conductivity distribution image, real-time detection is performed to determine whether there are one or more quality issues in the pouring process, including water seepage, pile hole wall collapse, uneven concrete slurry distribution, steel cage position offset, missing steel cage, or other quality issues in the construction process.

8. The method for detecting the quality of a bored pile during pouring with ERT sensing on both the inside and outside sides according to claim 2 is characterized by: The body of the measuring cylinder is made of an electrically insulating composite resin material with a high elastic modulus, and the cylinder body does not deform when subjected to impact.

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