Electrode device and method for tunnel electrical method advanced detection

Abstract

The application provides an electrode device and method for tunnel electric method advanced detection, which comprises an electrode, an expansion pipe and a plugging device. The electrode is a long-axis screw with threads on the surface, and the outside of the electrode is sleeved with the expansion pipe. The top end of the electrode is provided with a variable-diameter circular cone structure. A plurality of gaps are arranged on the circumference of the connection between the expansion pipe and the circular cone structure, so that the expansion pipe has a certain elasticity and is adapted to the variable-diameter of the circular cone structure. A plurality of holes are arranged on the circumference of the long-axis screw and the expansion pipe. The other end of the expansion pipe is provided with a nut, and the inside of the nut is provided with a thread structure matched with the threads. A through hole is arranged in the long-axis screw, and a piston core rod for propelling a coupling agent is movably arranged in the through hole. The plugging device is sleeved outside the expansion pipe and can slide along the expansion pipe to plug the holes on the expansion pipe. The electrode coupling with the surrounding rock can be further improved, the electrode can be conveniently disassembled, and the position of the electrode on the working face can be accurately positioned.

Description

Technical Field

[0001] This invention belongs to the field of electrical detection technology, and relates to an electrode device and method for electrical detection of tunnels. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] As the focus of water conservancy and transportation engineering construction shifts towards areas with complex topography, geology, and hydrology, increasingly complex geological disaster types and variable hazard factors urgently need to be addressed, posing a serious threat to construction safety. In the advanced prediction of adverse geological conditions in tunnels, obtaining information on water-bearing structures is particularly crucial for disaster assessment and early warning. Accurately acquiring the core attributes of hazard-causing water bodies, such as their spatial location, occurrence state, scale, and morphology, is the primary controlling geological factor in determining the scale of water inrush and mudslide disasters. Tunnel-induced polarization has unique advantages in the advanced detection of water-bearing geological structures and is widely used in engineering for the advanced detection of water-bearing structures in tunnels.

[0004] Tunnel-induced polarization (TEP) detection is an important geophysical exploration method. In this method, rod-shaped metal electrodes are commonly used, requiring pre-drilling holes at the tunnel face before inserting the electrodes. This results in poor coupling with the surrounding rock, leading to excessive grounding resistance. Grounding resistance is a crucial factor affecting the quality of electrical resistivity data acquisition; excessive resistance reduces the supply current and weakens the observation signal, thus decreasing the detection depth and accuracy. Furthermore, securing the electrodes in the holes is difficult, and they sometimes slip during measurement, causing interruptions. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes an electrode device and method for advanced electrical detection of tunnels. This invention further improves the coupling between the electrode and the surrounding rock and facilitates disassembly.

[0006] According to some embodiments, the present invention adopts the following technical solution:

[0007] An electrode device for advanced electrical detection of tunnels includes electrodes, an expansion tube, and a sealing device, wherein:

[0008] The electrode is a long-shaft screw with threads on its surface and an expansion tube sleeved on its outer side;

[0009] The top of the electrode is provided with a variable-diameter frustum structure, and the connection between the expansion tube and the frustum structure is provided with several gaps around the circumference to provide a certain degree of elasticity and to adapt to the variable diameter of the frustum structure; both the long shaft screw and the expansion tube are provided with several holes around the circumference.

[0010] The other end of the expansion tube is provided with a nut, and the inner side of the nut is provided with a thread structure that matches the thread.

[0011] The long-shaft screw has a through hole, and a piston core rod for propelling the coupling agent is movably disposed in the through hole;

[0012] The sealing device is sleeved on the outside of the expansion tube and can slide along the expansion tube to seal the hole on the expansion tube.

[0013] As an alternative implementation, the diameter of the frustum structure gradually increases outwards.

[0014] As an alternative implementation, as the nut is tightened, the gap at the front end of the expansion tube increases due to the force of the frustum structure, thus increasing the inner diameter of the front end of the expansion tube. This stabilizes the electrode within the borehole.

[0015] As an alternative implementation, the electrode has multiple holes around its circumference near the frustum structure.

[0016] As an alternative implementation, the piston rod includes a piston, a piston rod, and a piston handle arranged sequentially, wherein the piston handle is a cylindrical component with a diameter larger than that of the piston rod. This increases the force-bearing surface and facilitates the pushing action.

[0017] As an alternative implementation, the length of the electrode is greater than the length of the expansion tube.

[0018] As an alternative implementation, a lead wire is connected to the inside of the electrode.

[0019] As an alternative implementation, the expansion tube has multiple holes around its circumference near the gap.

[0020] As an alternative implementation, the expansion tube is provided with a pin near the nut.

[0021] As an alternative implementation, the sealing device includes an elastic element with a bayonet, the width of which is greater than the diameter of the hole, and a clamping element is movably connected to the bayonet.

[0022] A method for operating the above-mentioned electrode device includes the following steps:

[0023] Determine the drilling locations on the tunnel sidewalls or face;

[0024] The long shaft screw, expansion tube, and nut of the electrode device are placed into the borehole. By tightening the nut, the top of the expansion tube deforms and is fixed in the surrounding rock.

[0025] Fill the expansion tube with coupling agent;

[0026] Insert the piston rod into the long-shaft screw and push it forward, so that the coupling agent is pressed into the gap between the surrounding rock and the electrode along the radial holes on the long-shaft screw and the expansion tube;

[0027] After all the coupling agent is pressed in, if you feel the thrust of the piston rod suddenly increase and it cannot be pushed in, it means that the gap between the electrode and the surrounding rock has been filled. Stop the piston rod from moving forward.

[0028] Insert the pin into the tail end of the long shaft screw to fix the position of the piston core rod;

[0029] One end of the lead wire is fixed to the end of the long-shaft screw, and the other end is connected to the external transmission cable for detection;

[0030] After the detection is completed, turn off the power, reverse the nut to allow the expanded tube to recover, and remove the electrode;

[0031] Discharge the remaining coupling agent from the long-shaft screw and retract the electrode.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] The electrode device provided by this invention introduces a coupling agent through an axial hole in a long-shaft screw, which is then pressed into the gap between the surrounding rock and the electrode by a piston rod. A sealing device and a pin are designed on the long-shaft screw to improve the density of the coupling agent, increase conductivity, and solve the problem of coupling between the electrode and the surrounding rock.

[0034] The electrode device of the present invention has an expansion tube with a certain elasticity, which can expand and contract, allowing for quick disassembly of the electrode; by fixing the electrode to the working face through the expansion tube, it can prevent the electrode from falling off during the test and causing the test to be interrupted.

[0035] The electrode device of the present invention uses a coupling agent composed of saturated brine and clay. The saturated brine and clay are made into a fluid state, which has good conductivity and is simple to prepare and easy to obtain. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0037] Figure 1 This is a three-dimensional view of the electrode device;

[0038] Figure 2 A three-dimensional view of the long-axis screw of the electrode assembly;

[0039] Figure 3 A three-dimensional view of the expanded tube of the electrode device;

[0040] Figure 4A 3D view of the piston rod;

[0041] Figure 5 3D view of the sealing device

[0042] Among them, 1. long shaft screw, 2. expansion tube, 3. nut, 4. piston core rod, 5. lead wire, 6. expansion tube small hole, 7. sealing device, 8. fixing bayonet, 9. hard rubber ring, 10. pin, 11. long shaft screw small hole, 12. piston handle, 13. piston rod, 14. piston, 15. fixing bayonet screw hole. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] Example 1

[0047] An electrode device for electrical resistivity tomography (EDT) detection in tunnels, such as Figure 1-5 As shown, it includes: a long-shaft screw 1 (i.e., an electrode) with axial holes and radial bores, an expansion tube 2 wrapped around the long-shaft screw 1 and having four radial bores, a nut 3 for fixing the expansion tube, a piston rod 4 for pushing the coupling agent, a sealing device 7 for sealing, and a pin 10 for fixing the piston rod 4.

[0048] Among them, the long-shaft screw 1, expansion tube 2, nut 3, and piston rod 4 are all made of non-polarizable metal.

[0049] The expansion tube 2 is fitted onto the outside of the long shaft screw 1. As the nut 3 is tightened, the front end of the expansion tube 2 is opened by the force of the variable diameter position of the long shaft screw 1, and can be fixed inside the drill hole.

[0050] The piston rod 4 is located inside the long shaft screw 1 and can move freely and can also be freely removed from the long shaft screw 1.

[0051] The piston rod 4 is used to propel the coupling agent, so that the coupling agent enters the gap between the surrounding rock and the electrode along the radial hole of the long shaft screw and the radial hole on the expansion tube.

[0052] The piston 14 is connected to the piston rod 13, and the piston rod 13 is connected to the piston handle 12 by threads.

[0053] The sealing device 7 is used to seal the coupling agent flowing out along the gap between the surrounding rock and the electrode, and at the same time, it applies pressure to the coupling agent to increase its density. The sealing device 7 includes an elastic element with a latch (in this embodiment, it is a rigid rubber ring 9 with a fixing latch 8). The width of the elastic element is larger than the diameter of the hole. A clamping element is movably connected to the latch (in this embodiment, the fixing latch 8 is provided with a fixing latch screw hole 10, which can be used to adjust the diameter of the sealing device to abut against the expansion tube 2 and seal the coupling agent).

[0054] The pin 10 is used to fix the position after the piston rod 4 is pushed forward, to prevent the piston rod 4 from springing outward under certain pressure, and to fix the position.

[0055] Example 2

[0056] Embodiment 2 of the present invention provides a method for operating an electrode device for advanced electrical detection of tunnels as described in Embodiment 1, comprising the following steps:

[0057] 1. Determine the location of the borehole on the sidewall or face of the tunnel.

[0058] 2. Place the long shaft screw 1, expansion tube 2, and nut 3 from the electrode device into the borehole. Tighten the nut 3 to deform the top of the expansion tube 2 and fix it in the surrounding rock.

[0059] 3. Fill expansion tube 1 with coupling agent.

[0060] 4. Insert the piston rod 4 into the long-shaft screw 1 and push it forward so that the coupling agent is pressed into the gap between the surrounding rock and the electrode along the radial holes on the long-shaft screw 1 and the expansion tube 2.

[0061] 5. After all the coupling agent is pressed in, if you feel the thrust of the piston rod suddenly increase and it cannot be pushed in, it means that the gap between the electrode and the surrounding rock has been filled. Stop the piston rod 4 from moving forward.

[0062] 6. Insert the pin 10 into the tail end of the long shaft screw 1 to fix the position of the piston core rod 4.

[0063] 7. Fix one end of lead wire 5 to the end of long shaft screw 1, and connect the other end to the external transmission cable.

[0064] 8. Power on and conduct the detection.

[0065] 9. After the detection is complete, turn off the power. Reverse the nut 3 to return the expansion tube 2 to its original position, and remove the electrode.

[0066] 10. Discharge the remaining coupling agent from the long-shaft screw 1 and retract the electrode.

[0067] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An electrode device for electrical resistivity tomography (EDT) detection in tunnels, characterized in that, Includes electrodes, expansion tubes, and sealing devices, wherein: The electrode is a long-shaft screw with threads on its surface and an expansion tube sleeved on its outer side; The top of the electrode is provided with a variable-diameter frustum structure. The circumference of the connection between the expansion tube and the frustum structure is provided with several gaps to provide a certain degree of elasticity and to adapt to the variable diameter of the frustum structure. The diameter of the frustum structure gradually increases outward. Several expansion tube holes are provided on the circumference of the expansion tube. Multiple long-axis screw holes are provided on the circumference of the long-axis screw near the frustum structure. The other end of the expansion tube is provided with a nut, and the inner side of the nut is provided with a thread structure that matches the thread. The long-shaft screw has a through hole, and a piston core rod for propelling the coupling agent is movably disposed in the through hole; The sealing device is sleeved on the outside of the expansion tube and can slide along the expansion tube to seal the coupling agent flowing out of the gap between the surrounding rock and the electrode; wherein, the sealing device includes an elastic element with a latch, the elastic element being a hard rubber ring with a fixed latch, and a clamping element being movably connected at the latch.

2. The electrode device for tunnel electrical resistivity tomography (EPT) advance detection as described in claim 1, characterized in that, The piston core rod includes a piston, a piston rod, and a piston handle arranged in sequence, wherein the piston handle is a cylindrical part with a diameter larger than that of the piston rod.

3. The electrode device for tunnel electrical resistivity tomography (EPT) advance detection as described in claim 1, characterized in that, The length of the electrode is greater than the length of the expansion tube.

4. The electrode device for tunnel electrical resistivity tomography (EPT) advance detection as described in claim 1, characterized in that, The inner side of the electrode is connected to a lead wire.

5. The electrode device for tunnel electrical resistivity tomography (EPT) advance detection as described in claim 1, characterized in that, The expansion tube is provided with a pin near the nut.

6. The method of operating the electrode device as described in any one of claims 1-5, characterized in that, Includes the following steps: Determine the drilling locations on the sidewalls or face of the tunnel; The long shaft screw, expansion tube, and nut of the electrode device are placed into the borehole. By tightening the nut, the top of the expansion tube deforms and is fixed in the surrounding rock. Fill the long-shaft screw with coupling agent; Insert the piston rod into the long-shaft screw and push it forward, so that the coupling agent is pressed into the gap between the surrounding rock and the electrode along the small hole of the long-shaft screw and the radial hole of the expansion tube. After all the coupling agent is pressed in, if you feel that the thrust of the piston rod suddenly increases and it cannot be pushed in, it means that the gap between the electrode and the surrounding rock has been filled. Stop pushing the piston rod forward. Insert the pin into the tail end of the long shaft screw to fix the position of the piston core rod; One end of the lead wire is fixed to the end of the long-shaft screw, and the other end is connected to the external transmission cable for detection; After the detection is completed, turn off the power, reverse the nut to allow the expanded tube to recover, and remove the electrode; Discharge the remaining coupling agent from the long-shaft screw and retract the electrode.

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