Well fluid plugging mechanism and detection device for tunnel cross-hole CT

Abstract

The utility model provides a kind of well fluid plugging mechanism and detecting device for tunnel hole crossing CT, belong to tunnel construction technical field, wherein, well fluid plugging mechanism includes detection rod and mounting ring, the mounting ring is fixedly sleeved in the outer end surface of detection rod, the inner end of the detection rod is inserted into borehole, the inner end surface of the mounting ring is equipped with expansion air bag, air passage is opened in the side wall of the mounting ring, the air passage penetrates mounting ring outer end face, air passage side wall is equipped with air hole, the air hole is connected with the air passage in the expansion air bag inside.The well fluid plugging is fast, convenient, simple structure, easy to install and disassemble, ensure the high quality transmission of seismic wave signal, improve the accuracy and reliability of the detection of adverse geologic body, provide strong support effect for tunnel construction safety.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction technology, specifically to a well fluid sealing mechanism and detection device for tunnel cross-hole CT. Background Technology

[0002] In tunnel and underground engineering construction, unknown adverse geological features (such as faults, fracture zones, karst caves, and water-rich areas) in and around the construction site are a major contributing factor to serious safety accidents such as water inrush, mudslides, and collapses. Therefore, conducting precise geological surveys of the geological conditions within the tunnel's influence area before or during construction—that is, carrying out advanced geological forecasting and detailed exploration—is an indispensable and crucial step in ensuring construction safety, optimizing design schemes, and mitigating geological disaster risks.

[0003] Among numerous geophysical exploration methods, cross-hole seismic computed tomography (CT) has become one of the most advanced techniques in the field due to its significant advantages, including high detection accuracy, good resolution, and intuitive imaging results. This technology is widely used on both sides of the tunnel design axis, below the invert arch, above the arch crown, and other potential risk areas requiring close monitoring (such as suspected faults or water-rich zones). Its aim is to accurately determine the integrity of the rock mass and identify the spatial location and scale of adverse geological bodies such as karst caves and fracture zones.

[0004] The basic principle and implementation process of cross-hole seismic CT technology are as follows: In the tunnel planning area or excavated area, two or more boreholes, typically tens of meters deep, are drilled according to the detection design scheme. During operation, one borehole is used as the transmitting borehole, with a seismic wave transmitting probe installed inside; the remaining boreholes are used as receiving boreholes, with an array of receiving probes consisting of multiple sensors deployed within them. By exciting seismic waves and receiving the signals after they pass through the rock mass between the boreholes, characteristic parameters such as travel time, amplitude, and frequency of the seismic waves are obtained. Subsequently, a specialized tomographic inversion algorithm is used to process and calculate the large amount of data collected, ultimately reproducing the seismic wave velocity field distribution map of the rock mass between the boreholes. Since wave velocity is closely related to the density, integrity, and mechanical properties of the rock mass, anomalous regions in the wave velocity field (such as low-velocity anomalies, which usually indicate fracturing, water abundance, or karst development) can be identified to achieve a detailed characterization and geological interpretation of the internal structure of the detection area.

[0005] As engineering requirements become more diverse and complex, the layout of boreholes has become more flexible, no longer limited to traditional vertical or horizontal holes. To adapt to specific detection targets (such as investigating fracture zones at specific angles above the tunnel arch) or to employ new detection methods, inclined boreholes are often designed and constructed. However, this technological advancement has also brought new engineering challenges. To ensure good coupling between the seismic probe and the borehole wall rock mass, and to guarantee efficient transmission and reception of seismic wave signals, the borehole usually needs to be filled with well fluid (most commonly water). When the borehole is arranged horizontally or inclined upwards along the tunnel axis, the well fluid inside will naturally flow out due to gravity, failing to remain effectively in the borehole and causing the probe to malfunction.

[0006] To address this issue, the current engineering solution typically involves grouting at the borehole opening, either horizontally or inclined upwards. While this method can prevent well fluid outflow to some extent, it has significant drawbacks: First, the grouting process itself is time-consuming, requiring time for the grout to solidify, reducing on-site construction efficiency. Second, after completing the exploration task, removing the sealing structure (such as breaking the solidified grout) is cumbersome and inconvenient, and may damage the borehole opening. Therefore, existing well fluid plugging methods have become a bottleneck restricting the efficient application of inclined borehole cross-hole seismic CT technology, urgently requiring a more convenient and efficient plugging technology and device to solve this problem. Utility Model Content

[0007] One objective of this invention is to provide a well fluid sealing mechanism for cross-hole CT in tunnels, which solves the problems of low construction efficiency and difficulty in removing the sealing structure when grouting and sealing at the borehole opening in the prior art; the second objective is to provide a detection device for cross-hole CT in tunnels.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A well fluid sealing mechanism for cross-hole CT in tunnels includes a probe rod and a mounting ring. The mounting ring is fixedly fitted onto the outer end surface of the probe rod, and the inner end of the probe rod is inserted into the borehole. An inflatable airbag is installed on the inner end surface of the mounting ring. An air passage is provided in the side wall of the mounting ring, and the air passage penetrates the outer end face of the mounting ring. A vent is provided in the side wall of the air passage, and the vent connects the inside of the inflatable airbag with the air passage.

[0009] Furthermore, clamps are installed at both ends of the inflatable airbag, and the inflatable airbag is fixed to the mounting ring by the clamps.

[0010] Furthermore, there are two air passages, which are evenly distributed along the circumference of the mounting ring.

[0011] Furthermore, each of the air passages is connected to an air pipe connector at its outer end.

[0012] Furthermore, both sides of the outer end of the probe rod or mounting ring are provided with connecting parts, and connecting parts are provided with connecting members for connecting to the main body of the tunnel structure.

[0013] Furthermore, the connecting part can be any one of a lug, a sling, or a connecting ring.

[0014] Furthermore, the connecting component is a tether rope and an expansion bolt. The expansion bolt is used to drive into the main body of the tunnel structure. One end of the tether rope is fixedly connected to the connecting part, and the other end is fixedly connected to the expansion bolt. Alternatively, the connecting component is an iron chain and an expansion bolt. The expansion bolt is used to drive into the main body of the tunnel structure. One end of the iron chain is fixedly connected to the connecting part, and the other end is fixedly connected to the expansion bolt.

[0015] On the other hand, this utility model also proposes a tunnel cross-hole CT detection device, including a seismic wave transmitting unit and a seismic wave receiving unit. The seismic wave transmitting unit includes at least one transmitting probe and a well fluid sealing mechanism as described above. The seismic wave receiving unit includes at least one receiving probe and a well fluid sealing mechanism as described above. The transmitting probe and receiving probe are respectively fixed on the detection rod of the corresponding well fluid plugging mechanism; A through hole is opened in the middle of the probe rod.

[0016] Furthermore, both the transmitting probe and the receiving probe are provided with wires, and the mounting ring has a through hole for the wires to pass through.

[0017] Furthermore, an annular mounting groove is provided on the outer side of the sidewall of the wire hole, and a rubber sealing ring (not shown in the figure) is provided in the annular mounting groove.

[0018] The beneficial effects of this utility model are: 1. This application achieves rapid and convenient well fluid sealing by inserting a probe rod into the borehole and inflating an expansion bladder through an external air source via an air passage and vent. The inflated bladder presses firmly against the inner wall at the borehole opening. This mechanism eliminates the need for grouting, avoiding the time spent waiting for grout to solidify and the damage during removal, significantly improving the construction efficiency of cross-bore seismic CT detection. Furthermore, the device's simple structure and convenient installation and disassembly ensure high-quality transmission of seismic wave signals, thereby enhancing the accuracy and reliability of detecting adverse geological formations and providing strong support for tunnel construction safety.

[0019] 2. When facing an upward-sloping borehole, the inflatable airbag is in close contact with the inner wall of the borehole, and there is a large friction between the two, which allows the probe rod to be fixed inside the borehole.

[0020] 3. This application effectively fixes the position of the entire mechanism in the borehole by setting a connecting part at the outer end of the probe rod or mounting ring and connecting it to the main body of the tunnel structure through a connector, preventing displacement caused by borehole tilting or vibration, and ensuring the stability of the detection process and the accuracy of the data. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the well fluid plugging mechanism of this utility model; Figure 2 This is a partial cross-sectional structural diagram of the well fluid plugging mechanism of this utility model; Figure 3 This is a schematic diagram of the detection device in this utility model.

[0022] The components include: 1. Detector rod; 2. Mounting ring; 3. Inflatable airbag; 4. Clamp; 5. Receiver probe; 6. Wire; 7. Threading hole; 8. Air passage; 9. Vent hole; 10. Connector; 11. Air pipe connector; 12. Well fluid; 13. Receiver hole; 14. Through hole; and 15. Roller. Detailed Implementation

[0023] The embodiments of this utility model will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be understood that the preferred embodiments are only for illustrating this utility model and not for limiting the scope of protection of this utility model.

[0024] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0025] On the one hand, this embodiment proposes a well fluid sealing mechanism for cross-hole CT in tunnels, such as... Figures 1 to 2As shown, the borehole used for cross-hole CT detection in tunnels, in this embodiment, refers to a hole drilled along the tunnel axis. The well fluid 12 sealing mechanism includes a probe rod 1 and a mounting ring. The mounting ring is fixedly fitted onto the outer end surface of the probe rod 1, and the inner end of the probe rod 1 is inserted into the borehole. An inflatable airbag 3 is installed on the inner end surface of the mounting ring. An air passage 8 is provided inside the side wall of the mounting ring, and the air passage 8 penetrates the outer end face of the mounting ring. A vent hole 9 is provided on the side wall of the air passage 8, which connects the interior of the inflatable airbag 3 to the air passage 8. In this embodiment, the number of vent holes 9 can be multiple, depending on the length of the inflatable airbag 3, and the multiple vent holes 9 are evenly distributed along the axial direction of the probe rod 1.

[0026] Both ends of the inflatable airbag 3 are fitted with clamps 4, which fix the inflatable airbag 3 to the mounting ring. The clamps 4 tighten both ends of the inflatable airbag 3 to prevent air leakage.

[0027] There are two air passages 8, which are evenly distributed along the circumference of the mounting ring. In this embodiment, by setting two air passages 8, the inflatable airbag 3 is subjected to uniform force during inflation, avoiding the uneven inflation or airbag deformation problems that may be caused by a single air passage 8, thereby improving the sealing performance and consistency of the seal.

[0028] Each air passage 8 is connected to an air pipe connector 11 at its outer end, which facilitates quick connection and disconnection with an external air source, simplifies the inflation operation, and improves the convenience and efficiency of on-site construction.

[0029] Both sides of the outer end of the probe rod 1 or mounting ring are provided with connecting parts 10, and connecting parts 10 are provided with connecting components (not shown in the figure). The connecting components are used to connect with the main body of the tunnel structure. The connecting part 10 can be any one of a lug, a lifting lug, or a connecting ring. The connecting component is a rope and an expansion bolt. The expansion bolt is used to drive into the main body of the tunnel structure. One end of the rope is fixedly connected to the connecting part 10, and the other end is fixedly connected to the expansion bolt. Alternatively, the connecting component is an iron chain and an expansion bolt. The expansion bolt is used to drive into the main body of the tunnel structure, and one end of the iron chain is fixedly connected to the connecting part 10, and the other end is fixedly connected to the expansion bolt. In the above embodiments, a connecting part 10 is provided at the outer end of the detection rod 1 or the mounting ring, and is connected to the main tunnel structure through a connector, effectively fixing the position of the entire mechanism in the borehole, preventing displacement caused by borehole tilting or vibration, and ensuring the stability and data accuracy of the detection process. For example, when the connector is a rope and an expansion bolt, the expansion bolt is driven into the main tunnel structure outside the borehole opening, with the outer end of the expansion bolt protruding outside the main tunnel structure. One end of the rope is tied to the outer end of the expansion bolt, and the other end is tied to the connecting part 10, so that the entire sealing mechanism can be fixed inside the borehole.

[0030] On the other hand, this embodiment also proposes a detection device for tunnel cross-hole CT, such as... Figure 3As shown, the system includes a seismic wave transmitting unit and a seismic wave receiving unit. The seismic wave transmitting unit includes at least one transmitting probe and the aforementioned well fluid 12 sealing mechanism. The seismic wave receiving unit includes at least one receiving probe 5 and the aforementioned well fluid 12 sealing mechanism. The transmitting probe and receiving probe 5 are respectively fixed to the probe rod 1 of the corresponding well fluid 12 sealing mechanism. The probes can be fixed by adhesive, binding, or bolts. These fixing methods are common in existing technologies and will not be elaborated further here. A through hole 14 is formed in the middle of the probe rod 1. In this embodiment, by forming a through hole 14 on the probe rod 1, the outer end of the probe rod 1 extends out of the borehole during cross-hole CT detection, facilitating connection to the pumping system via a water pipe connector. The pumping system is existing technology and can pump the well fluid 12 into the stop hole.

[0031] Both the transmitting probe and the receiving probe 5 are equipped with wires 6, and the mounting ring has a through hole 7 for the wires 6 to pass through. When there are multiple transmitting probes, they are connected end to end in sequence along the axial direction of the detection rod 1 via wires 6; when there are multiple receiving probes 5, they are connected end to end in sequence along the axial direction of the detection rod 1 via wires 6.

[0032] An annular mounting groove is provided on the outer side wall of the wire hole 7, and a rubber sealing ring is provided in the annular mounting groove to increase the sealing of the wire hole 7 and prevent the well fluid 12 from flowing out of the wire hole 7.

[0033] Currently, as needed, the drilling methods for cross-hole CT detection during tunnel construction are becoming increasingly diverse. The layout of these boreholes is not limited to the traditional parallel to the tunnel axis, but is flexible and varied. For example, when drilling at the tunnel face, these holes are divergent along the tunnel axis to obtain a larger detection range. This means that these boreholes may be inclined downwards, inclined upwards, or parallel to the tunnel axis. Typically, only one transmitting hole is set up, and the remaining holes are used as receiving holes 13. The transmitting unit is placed in the transmitting hole to generate seismic waves, and the receiving unit is placed in the receiving hole 13 to receive seismic waves. For ease of operation and cost-saving, the transmitting hole is usually a downward-sloping drill hole. On the probe rod 1 of the transmitting hole, only one or a few transmitting probes are set up. On the probe rod 1 of the receiving hole 13, several receiving probes 5 are set up on each probe rod 1. The receiving probes 5 are arranged at equal intervals along the axial direction of the probe rod 1 (such as 0.5m, 1m or 2m). When the probe rod 1 is inserted into the receiving hole 13, each receiving probe 5 forms several receiving nodes. In the transmitting hole, a transmitting node is set up for each receiving node. The probe rod 1 in the transmitting hole is first fully inserted. After the innermost transmitting node generates seismic waves for detection, the probe rod 1 and the transmitting probe are moved outward so that the transmitting probe moves to the next transmitting node for detection again. This cycle is repeated until all transmitting nodes have been detected. It should be noted that, since the space inside the tunnel is limited when the borehole is inclined, and the borehole depth is usually tens of meters, the entire probe rod 1 is not convenient or can not be used for detection operations in the narrow tunnel space. Therefore, the probe rod 1 can be designed as a segmented type, and two adjacent probe rods 1 can be sealed and spliced, such as by using threads and using O-rings for sealing, which facilitates handling and operation.

[0034] In the above embodiments, in order to facilitate the smooth deployment and removal of the probe rod 1, a roller can be set at the front end of the probe rod 1 so that the axis of the probe rod 1 coincides with the axis of the borehole as much as possible, so that the inflatable airbag 3 can seal the borehole more evenly and stably.

[0035] Working principle: Taking one transmitting hole and multiple receiving holes 13 as an example, along the tunnel axis, the transmitting hole is inclined downwards, and the receiving hole 13 may be inclined downwards, horizontally, or inclined upwards.

[0036] The launching probe is used and fixed on the probe rod 1 to form a launching unit. Then the probe rod 1 is fully inserted into the launching hole until the launching probe reaches the launching node position at the innermost end of the launching hole. Since the launching hole is inclined downward, there is no need to plug it after filling the well fluid 12. Since the launching probe needs to move inside the launching hole, the probe rod 1 does not need to be fixed inside the launching hole. Therefore, the probe rod 1 of the launching unit does not need to be designed with a plugging mechanism, connecting part 10, connecting parts and other structures.

[0037] Each receiving hole 13 contains a receiving unit, and each receiving unit has multiple receiving probes 5 mounted on its probe rod 1. The wire 6 of the outermost receiving probe 5 passes through the wire hole 7 and extends out of the receiving hole 13. The probe rod 1 of each receiving unit is inserted into the corresponding receiving hole 13 until all the receiving probes 5 coincide with the position of each receiving node. For a downwardly inclined receiving hole 13, the structure of its receiving unit can be the same as that of the transmitting unit, i.e., there is no need to use a plugging mechanism, connecting part 10, connecting parts, etc. For a horizontally set receiving hole 13, only a plugging mechanism can be set without the need for connecting part 10 and connecting parts. For an upwardly inclined receiving hole 13, a well fluid 12 plugging mechanism, connecting part 10, and connecting parts are required. Taking an upwardly inclined receiving hole 13 as an example, after the probe rod 1 is inserted into place, a dual-purpose air pump for charging and discharging is used in conjunction with a solenoid valve to charge and discharge the expansion air bag 3. The dual-purpose air pump for charging and discharging can be connected to two air pipe joints 11 through a three-way pipe. One end of the three-way pipe is connected to the air port of the dual-purpose air pump for charging and discharging. The other two ends of the tube are connected to two air pipe connectors 11 respectively. First, the expansion airbag 3 is inflated so that the expansion airbag 3 is tightly attached to the inner wall of the receiving hole 13 to complete the sealing. Then, the probe rod 1 is fixed in the receiving hole 13 through the connecting part 10 and the connecting piece. The probe rod 1 is fixed in the receiving hole 13. The well fluid 12 is pumped into the receiving hole 13 and filled through the pumping system connected to the outer end of the probe rod 1. The transmitting probe excites seismic waves at each transmitting node in sequence. All the receiving probes 5 receive the seismic waves synchronously to complete the tunnel cross-hole CT detection. After the detection is completed, the expansion airbag 3 is deflated. Since the total amount of well fluid 12 is small, it can be allowed to flow out naturally. Then, the connecting piece is disconnected and the transmitting unit and receiving unit are retrieved.

[0038] The above embodiments are merely preferred embodiments provided to fully illustrate the present utility model, and the protection scope of the present utility model is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present utility model are all within the protection scope of the present utility model.

Claims

1. A well fluid sealing mechanism for cross-hole CT in tunnels, used inside the borehole for cross-hole CT detection in tunnels, characterized in that: The device includes a probe rod and a mounting ring. The mounting ring is fixedly fitted onto the outer end surface of the probe rod. The inner end of the probe rod is inserted into a drill hole. An inflatable airbag is installed on the inner end surface of the mounting ring. An air passage is provided inside the side wall of the mounting ring. The air passage passes through the outer end face of the mounting ring. A vent is provided on the side wall of the air passage, and the vent connects the inside of the inflatable airbag to the air passage.

2. The well fluid sealing mechanism for tunnel cross-hole CT according to claim 1, characterized in that: Both ends of the inflatable airbag are fitted with clamps, and the inflatable airbag is fixed to the mounting ring by the clamps.

3. The well fluid sealing mechanism for tunnel cross-hole CT according to claim 1, characterized in that: There are two air passages, which are evenly distributed along the circumference of the mounting ring.

4. The well fluid sealing mechanism for tunnel cross-hole CT according to claim 3, characterized in that: Each of the air passages is connected to an air pipe connector at its outer end.

5. The well fluid sealing mechanism for tunnel cross-hole CT according to claim 1, characterized in that: Both sides of the outer end of the probe rod or mounting ring are provided with connecting parts, and connecting parts are provided with connecting members for connecting to the main body of the tunnel structure.

6. The well fluid sealing mechanism for tunnel cross-hole CT according to claim 5, characterized in that: The connecting part can be any one of a lug, a sling, or a connecting ring.

7. The well fluid sealing mechanism for tunnel cross-hole CT according to claim 5, characterized in that: The connecting components are a tether rope and an expansion bolt. The expansion bolt is used to drive into the main body of the tunnel structure. One end of the tether rope is fixedly connected to the connecting part, and the other end is fixedly connected to the expansion bolt. Alternatively, the connecting components are an iron chain and an expansion bolt. The expansion bolt is used to drive into the main body of the tunnel structure. One end of the iron chain is fixedly connected to the connecting part, and the other end is fixedly connected to the expansion bolt.

8. A detection device for cross-hole CT in tunnels, characterized in that: It includes a seismic wave transmitting unit and a seismic wave receiving unit. The seismic wave transmitting unit includes at least one transmitting probe and a well fluid plugging mechanism as described in any one of claims 1-7. The seismic wave receiving unit includes at least one receiving probe and a well fluid plugging mechanism as described in any one of claims 1-7. The transmitting probe and receiving probe are respectively fixed on the detection rod of the corresponding well fluid plugging mechanism; A through hole is opened in the middle of the probe rod.

9. The detection device for tunnel cross-hole CT according to claim 8, characterized in that: Both the transmitting probe and the receiving probe are equipped with wires, and the mounting ring has a through hole for the wires to pass through.

10. The detection device for tunnel cross-hole CT according to claim 9, characterized in that: An annular mounting groove is provided on the outer side of the sidewall of the threading hole, and a rubber sealing ring is provided in the annular mounting groove.

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