Soil reinforcement effect detection equipment and detection method based on electrical resistance tomography

Abstract

The invention relates to the technical field of resistivity method geophysical prospecting detection, and discloses a soil reinforcement effect detection device and method based on electrical resistance tomography. The technical problems that in the prior art, an electrode device is difficult to cover the whole pile body, so that an imaging result has certain limitation, and the electrode device is difficult to adapt to pile bodies of different sizes and shapes are solved. The device comprises a rotary spray irrigation pile, a high-pressure slurry pump and an air compressor, the rotary spray irrigation pile comprises a pipe wall and a grouting pipe, a plurality of electrodes are arranged on the outer side of the pipe wall at intervals, an electrode line channel is arranged on the inner side of the pipe wall, and the electrodes are connected through a wire penetrating through the electrode line channel to form an electrode measurement network. The device has the advantages that the reinforcing process of the rotary spray irrigation pile is monitored in real time, and the physical characteristics of foundation soil or a reinforcing body are accurately analyzed.

Description

Technical Field

[0001] The invention relates to the technical field of resistivity geophysical detection, and in particular to a soil reinforcement effect detection device and a detection method based on electrical resistance tomography. Background Art

[0002] As a common foundation treatment method, jet grouting piles have been widely used in various engineering fields. Concrete is sprayed into the soil layer through a high-pressure rotating nozzle to form a pile body with high strength and stability, thereby improving the bearing capacity and stability of the foundation. However, due to many uncertain factors in the construction process of jet grouting piles, such as the complexity of the soil layer and the differences in construction technology, its reinforcement effect is often difficult to achieve the expected goal. Therefore, how to effectively detect and evaluate the reinforcement effect of jet grouting piles has become an urgent problem to be solved in the engineering community.

[0003] Traditional methods for testing the reinforcement effect of jet grouting piles mainly include core sampling, standard penetration test and static load test. Although these methods can reflect the quality and reinforcement effect of the pile body to a certain extent, they have some limitations that are difficult to overcome. For example, core sampling can only obtain a limited number of samples, which is difficult to fully reflect the quality of the entire pile body; although standard penetration test and static load test can evaluate the bearing capacity and stability of the pile body, they require destructive drilling and loading of the pile body, which is not only time-consuming and labor-intensive, but also causes certain damage to the project.

[0004] In recent years, with the development of electrical resistance tomography technology, a new non-invasive and radiation-free method has been provided for the detection of the reinforcement effect of jet-cast piles. Electrical resistance tomography technology is an imaging method based on resistivity difference. By arranging electrodes around the jet-cast piles, applying a certain current and voltage, and measuring the change in resistivity, the internal structure of the pile and the reinforcement effect can be detected.

[0005] However, there are still some problems with the existing electrical resistance tomography technology in the detection of the reinforcement effect of rotary jet cast-in-place piles. First, due to the large size of the rotary jet cast-in-place piles, the existing electrode device is difficult to cover the entire pile body, resulting in certain limitations in the imaging results. Secondly, most of the existing electrode devices adopt a fixed or mobile arrangement, which is difficult to adapt to piles of different sizes and shapes, limiting its scope of application in actual engineering. Therefore, it is necessary to study a new rotary jet cast-in-place pile reinforcement electrode device that can be used for electrical resistance tomography to achieve comprehensive and accurate detection of the internal structure of the pile body and the reinforcement effect. Summary of the invention

[0006] In view of the above technical problems, the present disclosure provides a soil reinforcement effect detection device and detection method based on electrical resistance tomography, which solves the technical problem in the prior art that the electrode device is difficult to cover the entire pile body, resulting in certain limitations in the imaging results and difficulty in adapting to piles of different sizes and shapes.

[0007] The device can realize resistance precipitation during the construction of the jet grouting pile by setting electrodes in the pile body of the jet grouting pile, thereby improving the reinforcement effect of the jet grouting pile. Compared with the existing electrode device, the device of the present invention has the advantages of simple structure, convenient construction, low energy consumption, good effect, etc., and has important practical value and broad application prospects.

[0008] According to one aspect of the present disclosure, there is provided a soil reinforcement effect detection device based on electrical resistance tomography, comprising a rotary jet cast-in-place pile capable of accommodating grouting material, wherein the jet port of the rotary jet cast-in-place pile is connected to the outlet of a high-pressure mud pump via a pipeline, the compressed air inlet of the rotary jet cast-in-place pile is connected to an air compressor, the rotary jet cast-in-place pile comprises a pipe wall and a grouting pipe installed in the pipe wall, a plurality of electrodes are arranged at intervals along the longitudinal and transverse directions on the outer side of the pipe wall of the rotary jet cast-in-place pile, the spacing between the electrodes is set to match the size of the grouting pipe of the rotary jet cast-in-place pile, an electrode line channel is arranged on the inner side of the pipe wall of the rotary jet cast-in-place pile, the electrodes are connected via a wire passing through the electrode line channel to form an electrode measurement network, the electrodes are excited to measure electrical signals, and data imaging is inverted.

[0009] In some embodiments of the present disclosure, the grouting material includes cement slurry and chemical slurry.

[0010] In some embodiments of the present disclosure, the electrode material is stainless steel or copper or graphite.

[0011] In some embodiments of the present disclosure, the conductor is a waterproof conductor, a hub is installed on the outside of the waterproof conductor via a waterproof rubber ring, a plurality of grooves are arranged on the outer surface of the hub, the hub is installed on the inner wall of the rotary jet cast-in-place pile via a plurality of clip-on structures, the clip-on structure includes a clip-on plate, one end of the clip-on plate is clipped into the groove, and the other end is installed on the inner wall of the rotary jet cast-in-place pile via a spring.

[0012] According to another aspect of the present disclosure, a soil reinforcement effect detection method based on electrical resistance tomography is provided, comprising the following steps: (1) Electrode arrangement: Before the construction of jet grouting piles, the horizontal and vertical electrodes are designed according to the diameter, length and imaging accuracy requirements of the jet grouting pipe to cover the area to be monitored; (2) Electrode connection: The electrodes are connected through wires to form an electrode measurement network; the outer side of the wire is wrapped with a waterproof rubber ring and installed into the hub in turn, one end of the spring connecting the card and the board is pressed to make the other end of the card and the board tilt up, and the hub is installed so that the groove above the hub is at the corresponding position of the card and the board, and the card and the board are loosened, and the card and the board are installed in the groove of the hub to fix the hub; (3) Jet-jet reinforcement: Use jet-jet piles to spray grouting materials into the foundation through high-pressure jetting. During the spraying process, the grouting materials mix with the foundation soil to form a reinforcement body to improve the bearing capacity and stability of the foundation. (4) Resistance measurement: During or after the construction of the jet-cast pile, the electrodes are excited to obtain resistance measurement data inside the foundation soil or reinforcement body; (5) Tomography: Resistivity imaging technology is used to convert resistivity data into resistivity images or three-dimensional models. By analyzing the images or models, the physical properties, structural status and potential problems of the foundation soil or reinforcement can be understood.

[0013] The beneficial effects of the present invention are: 1. Real-time monitoring: Through the electrode device and resistance measurement system, the electrical resistance tomography can monitor the resistivity changes in the process of jet grouting pile reinforcement in real time, timely discover and deal with potential problems, and improve construction quality and efficiency.

[0014] 2. Accurate analysis: Resistivity imaging technology can provide high-precision resistivity distribution images or three-dimensional models, which helps to accurately analyze the physical properties of foundation soil or reinforcement.

[0015] 3. Guide construction: The results of electrical resistance tomography can be used to guide the construction process of rotary jet grouting piles, optimize the construction plan, and improve the reinforcement effect and quality.

[0016] 4. Non-invasive: ERT technology does not require drilling and loading of the pile, will not cause damage to the project, and can be used for testing without affecting the construction progress and quality.

[0017] 5. No radiation: Electrical resistance tomography technology does not involve radioactive substances, will not cause harm to the human body and the environment, and has high safety and environmental protection.

[0018] 6. High resolution: ERT technology has a high resolution and can clearly display the fine structure and defects inside the pile body, so as to more accurately evaluate the reinforcement effect.

[0019] 7. The hub is installed on the outside of the waterproof wire through a waterproof rubber ring, which can effectively prevent groundwater or construction water from entering the wire, ensure the safe operation of the electrical system, and avoid short circuits or other electrical failures caused by water intrusion.

[0020] 8. The hub is installed on the inner wall of the rotary jet cast-in-place pile through a card-and-type structure, ensuring that the hub is firmly fixed in the designated position, and can also adapt to vibration and displacement during construction, reducing wire damage caused by mechanical movement.

[0021] 9. The card-and-type structure includes a card-connecting plate and a spring design, making the installation and removal of the hub simple and quick. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a bottom view of the rotary jet cast-in-place pile; Figure 2 This is the front view of the rotary jet cast-in-place pile; Figure 3 This is a partial enlarged view of the electrode of the rotary jet grouting pile; Figure 4 This is a schematic diagram of the connection between the high-pressure mud pump and the air compressor; Figure 5 It is a flow chart of the method for detecting the reinforcement effect of rotary jetting grouting piles by electrical resistance tomography; Figure 6 This is a schematic diagram of the waterproof wire installation structure; Figure 7 Another perspective structural diagram of waterproof wire installation; Figure 8 This is a schematic diagram for field verification; Fig. 9 It is the effect diagram of the test and certification of the tomography equipment; The names of the components in the figure are: 1. Jet-cast pile; 2. High-pressure mud pump; 3. Air compressor; 4. Pipe wall; 5. Grouting pipe; 6. Electrode; 7. Electrode line channel; 8. Waterproof wire; 9. Hub; 10. Groove; 11. Snap-in plate; 12. Spring. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. Example 1

[0024] This example discloses a soil reinforcement effect detection device and detection method based on electrical resistance tomography, see Figures 1 to 9 ; The soil reinforcement effect detection equipment based on electrical resistance tomography comprises a rotary jet cast-in-place pile 1 for accommodating grouting materials, the jet port of the rotary jet cast-in-place pile 1 is connected to the outlet of a high-pressure mud pump 2 via a pipeline, the compressed air inlet of the rotary jet cast-in-place pile 1 is connected to an air compressor 3, the rotary jet cast-in-place pile 1 comprises a pipe wall 4 and a grouting pipe 5 installed in the pipe wall 4, a plurality of electrodes 6 are arranged at intervals along the longitudinal and transverse directions on the outer side of the pipe wall 4 of the rotary jet cast-in-place pile, the spacing between the electrodes 6 is set to match the size of the grouting pipe 5 of the rotary jet cast-in-place pile 1, an electrode line channel 7 is set on the inner side of the pipe wall 4 of the rotary jet cast-in-place pile, and the electrodes 6 are connected via a wire passing through the electrode line channel 7 to form an electrode measurement network, the electrodes are excited to measure electrical signals, and data imaging is inverted.

[0025] Grouting materials include cement slurry and chemical slurry.

[0026] The electrode material is stainless steel, copper or graphite.

[0027] The conductor is a waterproof conductor 8, and a hub 9 is installed on the outside of the waterproof conductor 8 through a waterproof rubber ring. A plurality of grooves 10 are arranged on the outer surface of the hub 9. The hub 9 is installed on the inner wall of the rotary jet cast-in-place pile 1 through a plurality of card-and-type structures. The card-and-type structure includes a card-connecting plate 11. One end of the card-connecting plate 11 is carded in the groove 10, and the other end is installed on the inner wall of the rotary jet cast-in-place pile 1 through a spring 12.

[0028] A soil reinforcement effect detection method based on electrical resistance tomography comprises the following steps: (1) Electrode arrangement: Before the construction of jet grouting piles, the horizontal and vertical electrodes are designed according to the diameter, length and imaging accuracy requirements of the jet grouting pipe to cover the area to be monitored; (2) Electrode connection: The electrodes are connected through wires to form an electrode measurement network; the outer side of the wire is wrapped with a waterproof rubber ring and installed into the hub in turn, one end of the spring connecting the card and the board is pressed to make the other end of the card and the board tilt up, and the hub is installed so that the groove above the hub is at the corresponding position of the card and the board, and the card and the board are loosened, and the card and the board are installed in the groove of the hub to fix the hub; (3) Jet-jet reinforcement: Use jet-jet piles to spray grouting materials into the foundation through high-pressure jetting. During the spraying process, the grouting materials mix with the foundation soil to form a reinforcement body to improve the bearing capacity and stability of the foundation. (4) Resistance measurement: During or after the construction of the jet-cast pile, the electrodes are excited to obtain resistance measurement data inside the foundation soil or reinforcement body; (5) Tomography: Resistivity imaging technology is used to convert resistivity data into resistivity images or three-dimensional models. By analyzing the images or models, the physical properties, structural status and potential problems of the foundation soil or reinforcement can be understood.

[0029] See also Figure 8and Fig. 9 Show the test process of this application, Figure 8 Shown is a photo of a specific test pit at the construction site, in which Figure 8 The test pit corresponds to Fig. 9 In the red circle, Fig. 9 The spatial distribution of resistivity values ​​at different locations is mapped by color, and dark blue represents low resistivity areas. Therefore, the resistivity data measured in this application can be verified, providing a scientific basis for construction decisions.

[0030] Although some preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0031] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of this application and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A soil reinforcement effect detection device based on electrical resistance tomography, characterized in that: It comprises a rotary jet cast-in-place pile capable of accommodating grouting material, wherein the jet port of the rotary jet cast-in-place pile is connected to the outlet of a high-pressure mud pump via a pipeline, the compressed air inlet of the rotary jet cast-in-place pile is connected to an air compressor, the rotary jet cast-in-place pile comprises a pipe wall and a grouting pipe installed in the pipe wall, a plurality of electrodes are arranged at intervals along the longitudinal and transverse directions on the outer side of the pipe wall of the rotary jet cast-in-place pile, the spacing between the electrodes is set in accordance with the size of the grouting pipe of the rotary jet cast-in-place pile, an electrode line channel is arranged on the inner side of the pipe wall of the rotary jet cast-in-place pile, the electrodes are connected via a wire passing through the electrode line channel to form an electrode measurement network, measure electrical signals, and invert data imaging.

2. The soil reinforcement effect detection device based on electrical resistance tomography according to claim 1, characterized in that: The grouting material is cement slurry or chemical slurry.

3. The soil reinforcement effect detection device based on electrical resistance tomography according to claim 1, characterized in that: The electrode material is stainless steel, copper or graphite.

4. The soil reinforcement effect detection device based on electrical resistance tomography according to claim 1, characterized in that: The conductor is a waterproof conductor, and a hub is installed on the outside of the waterproof conductor via a waterproof rubber ring. A plurality of grooves are arranged on the outer surface of the hub. The hub is installed on the inner wall of the rotary jet cast-in-place pile via a plurality of clip-on structures. The clip-on structure includes a clip-on plate, one end of which is clipped into the groove, and the other end is installed on the inner wall of the rotary jet cast-in-place pile via a spring.

5. A soil reinforcement effect detection method based on electrical resistance tomography, characterized in that: The steps include: (1) Electrode arrangement: Before the construction of jet grouting piles, the horizontal and vertical electrodes are designed according to the diameter, length and imaging accuracy requirements of the jet grouting pipe to cover the area to be monitored; (2) Electrode connection: The electrodes are connected through wires to form an electrode measurement network; the outer side of the wire is wrapped with a waterproof rubber ring and installed into the hub in turn, one end of the spring connecting the card and the board is pressed to make the other end of the card and the board tilt up, and the hub is installed so that the groove above the hub is at the corresponding position of the card and the board, and the card and the board are loosened, and the card and the board are installed in the groove of the hub to fix the hub; (3) Jet-jet reinforcement: Use jet-jet piles to spray grouting materials into the foundation through high-pressure jetting. During the spraying process, the grouting materials mix with the foundation soil to form a reinforcement body to improve the bearing capacity and stability of the foundation. (4) Resistance measurement: During or after the construction of the jet-cast pile, the electrodes are excited to obtain resistance measurement data inside the foundation soil or reinforcement body; (5) Tomography: Resistivity imaging technology is used to convert resistivity data into resistivity images or three-dimensional models. By analyzing the images or models, the physical properties, structural status and potential problems of the foundation soil or reinforcement can be understood.

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