Time division single component sensor for borehole seismic exploration and method of use

Abstract

The application discloses a time-sharing single-component sensor for seismic detection in a hole and a use method thereof, and relates to the field of seismic detection. The time-sharing single-component sensor comprises a cylindrical carrier, a sensor core, a rotating shaft, a long rod, a short rod, a weight block, an open slot and a torsion spring. The rotating shaft is rotationally connected in the cylindrical carrier along the radial direction of the cylindrical carrier. One end of the long rod is fixedly connected with the rotating shaft. One end of the short rod is fixedly connected with the rotating shaft and forms an angle of 180 degrees with the long rod. The other end of the short rod is fixedly connected with an isolation layer. One end of the weight block is fixedly connected with the other end of the long rod. The weight of the weight block is lower than the sum of the weight of the isolation layer and the sensor core. The open slot is arranged on the surface of the cylindrical carrier. One end of the torsion spring is fixedly connected with the inner wall of the cylindrical carrier, and the other end is fixedly connected with the rotating shaft. The time-sharing single-component sensor can realize multi-component and multi-angle seismic signal measurement in one detection, and only one sensor core is needed, so that the hardware cost is saved.

Description

Technical Field

[0001] This invention relates to the field of borehole seismic detection devices, and particularly to a time-division single-component sensor for borehole seismic detection and its usage method. Background Technology

[0002] In their natural state, Earth's crustal rock strata are typically in a state of stress equilibrium. However, excavating tunnels within these strata alters their boundary conditions, disrupting this relative equilibrium and changing the natural stress field. This leads to a new stress equilibrium within a certain range around the tunnel. The so-called loosened zone is a stress-relaxed area formed within the surrounding rock due to this stress redistribution; it is also known as the loosened extent. Because the loosened zone exists within the surrounding rock and cannot be directly observed, it requires specific technical methods. Therefore, reliably measuring the extent of the loosened zone is a crucial concern for engineering technicians.

[0003] Chinese invention patent publication number CN106226810A discloses a borehole seismic probe and its surrounding rock detection device and method. The borehole seismic probe includes a source device and at least two signal receiving devices connected in sequence, with the source device located at the front end of the borehole seismic probe. Each signal receiving device includes a carrier, at least one sensor core, at least one wall-mounted coupling device, a vibration isolation device, and at least one sound insulation device. All the carriers of these signal receiving devices are arranged in a row, and at least one wall-mounted coupling device is provided on the outer wall of each carrier. Adjacent carriers are connected by a vibration isolation device. At least one sensor core is installed in each carrier, and these sensor cores in each carrier are covered by at least one sound insulation device. This patent achieves sensitivity in directions perpendicular to or parallel to the borehole extension direction of the borehole seismic probe by adjusting the placement angle of the sensor core. Once the sensor core is loaded into the carrier, the sensitivity direction of the sensor core cannot be changed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that once the existing borehole seismic probe is installed, the sensitivity direction of the sensor core cannot be changed, and multi-angle and multi-component measurements cannot be achieved in sequential detection. To this end, a time-division single-component sensor for borehole seismic detection and its usage method are provided.

[0005] The technical solution of this invention is: a time-division single-component sensor for borehole seismic detection, comprising: a cylindrical carrier; a sensor core, wherein the sensor core is placed inside the cylindrical carrier and covered by an isolation layer; a rotating shaft, wherein the rotating shaft is rotatably connected to the cylindrical carrier along its radial direction; a long rod, one end of which is fixedly connected to the rotating shaft; a short rod, one end of which is fixedly connected to the rotating shaft and forms a 180° angle with the long rod, and the other end of which is fixedly connected to the isolation layer; a counterweight, one end of which is fixedly connected to the other end of the long rod, the weight of which is less than the sum of the weights of the isolation layer and the sensor core; an opening slot, wherein the opening slot is formed on the surface of the cylindrical carrier, and when the long rod is perpendicular to the axial direction of the cylindrical carrier, a portion of the surface will be exposed outside the opening slot; and a torsion spring, one end of which is fixedly connected to the inner wall of the cylindrical carrier, and the other end of which is fixedly connected to the rotating shaft.

[0006] The improvement to the above solution also includes: a limiting plate, which is fixed inside the cylindrical carrier and located below the rotating shaft. When the counterweight contacts the limiting plate, the sensor core is parallel to the axis of the cylindrical carrier.

[0007] A further improvement to the above scheme is that the limiting plate is provided with a magnetic block and the counterweight is provided with magnetic material.

[0008] A further improvement to the above solution is that the cylindrical carrier is equipped with a soundproof cover, which encloses the sensor core, rotating shaft, long rod, short rod and opening slot.

[0009] Another improvement to the above solution is that the inner surface of the soundproof cover is covered with sound-absorbing material.

[0010] In the above scheme, the portion of the counterweight exposed outside the opening slot is wedge-shaped.

[0011] The method of using a time-division single-component sensor for borehole seismic detection involves connecting a cylindrical carrier to a seismic source device to form a borehole seismic probe. A guide rod is used to push the probe into the borehole, with the counterweight positioned above and partially exposed outside the opening slot, and the sensor core positioned below. Once the cylindrical carrier enters the borehole, the portion of the counterweight exposed outside the opening slot is pushed and rotates clockwise around the axis, fully entering the cylindrical carrier. This causes the sensor core to rotate clockwise around the axis, thus changing the sensitivity direction. As the torsion spring's torque gradually increases, the thrust on the counterweight disappears, and the sensor core and counterweight rotate counterclockwise back to their initial positions. This process is repeated.

[0012] The beneficial effect of this invention is that it enables the measurement of multi-component and multi-angle seismic signals in a single detection, eliminating the need for multiple sensor cores placed at different angles; only one sensor core is required, thus saving hardware costs. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the initial state of the time-division single-component sensor for borehole seismic detection according to the present invention; Figure 2 This is a schematic diagram of another state of the time-division single-component sensor for borehole seismic detection of the present invention; Figure 3 yes Figure 1 Schematic diagram of the centrally opened slot; Figure 4 yes Figure 1 Schematic diagram of the connection between the pivot shaft and the torsion spring; In the diagram, 1 is a cylindrical carrier, 2 is a sensor core, 3 is an isolation layer, 4 is a rotating shaft, 5 is a long rod, 6 is a short rod, 7 is a counterweight, 8 is an open slot, 9 is a torsion spring, 10 is a limiting plate, and 11 is a soundproof cover. Implementation

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments implemented by those skilled in the art without creative effort are within the protection scope of the present invention.

[0015] like Figure 1-4 As shown, a time-division single-component sensor for borehole seismic detection includes: a cylindrical carrier 1, which is hollow inside; a sensor core 2, which is placed inside the cylindrical carrier and covered by an isolation layer 3, which protects the sensor core; a rotating shaft 4, which is rotatably connected to the cylindrical carrier along its radial direction; a long rod 5, one end of which is fixed to the rotating shaft; a short rod 6, one end of which is fixed to the rotating shaft and forms a 180° angle with the long rod, and the other end of which is fixed to the isolation layer; a counterweight 7, one end of which is fixed to the other end of the long rod, and the weight of the counterweight is less than the sum of the weights of the isolation layer and the sensor core; an opening slot 8, which is formed on the surface of the cylindrical carrier, and when the long rod is perpendicular to the axial direction of the cylindrical carrier, part of the surface will be exposed outside the opening slot; and a torsion spring 9, one end of which is fixed to the inner wall of the cylindrical carrier, and the other end of which is fixed to the rotating shaft.

[0016] The present invention uses a long rod design to ensure that the counterweight can contact the borehole wall outside the cylindrical carrier when it is on top, thereby pushing it to rotate clockwise. The design of the opening slot extends along the axial direction of the cylindrical carrier, and the width of the opening slot matches the width of the counterweight.

[0017] As a preferred embodiment of the present invention, it further includes: a limiting plate 10, which is fixed inside the cylindrical carrier and located below the rotating shaft. When the counterweight contacts the limiting plate, the sensor core is parallel to the axial direction of the cylindrical carrier. The limiting plate is used to position the counterweight. When the counterweight rotates clockwise to approximately parallel to the axial direction of the cylindrical carrier, it is blocked by the limiting plate. At this time, the sensitivity direction of the sensor core also rotates by 90°. During the rotation of the sensor core, multi-component signals from 0° to 90° are collected.

[0018] As a preferred embodiment of the present invention, in order to ensure that the sensor core can rotate 90° clockwise, a magnetic block is provided on the limiting plate and a magnetic material is provided on the counterweight. In this way, when the counterweight rotates clockwise to be close to the limiting plate, the attraction between the magnetic block and the magnetic material causes the counterweight to continue rotating and contact the limiting plate. The magnetic force plays an auxiliary role in the rotation. The magnetic force, the self-weight of the sensor core, and the torsion of the torsion spring achieve a temporary balance. When the cylindrical carrier is subjected to external vibration, this balance is broken. The torsion of the torsion spring and the self-weight of the sensor core are greater than the magnetic force, causing the sensor core to return to the initial state. Part of the surface of the counterweight is exposed outside the opening groove of the cylindrical carrier again. This process is repeated.

[0019] In a preferred embodiment of the present invention, a soundproof cover 11 is provided inside the cylindrical carrier, which encloses the sensor core, rotating shaft, long rod, short rod, and opening slot. The inner surface of the soundproof cover is covered with sound-absorbing material, such as sound-absorbing cotton, foam material, etc.

[0020] As a preferred embodiment of the present invention, the portion of the counterweight exposed outside the opening slot is wedge-shaped. When the wedge interacts with the inner wall of the borehole, it can provide a downward thrust to the counterweight, thereby improving the pushing effect.

[0021] The method of using a time-division single-component sensor for borehole seismic detection involves connecting a cylindrical carrier to a seismic source device to form a borehole seismic probe. A guide rod is used to push the probe into the borehole, with the counterweight positioned above and partially exposed outside the opening slot, while the sensor core, due to its own weight, is positioned below. Once the cylindrical carrier enters the borehole, the portion of the counterweight exposed outside the opening slot is pushed and rotates clockwise around the axis, fully entering the cylindrical carrier. This causes the sensor core to rotate clockwise around the axis, thus changing the sensitivity direction. As the torsion spring's torque gradually increases, the thrust on the counterweight disappears, and the sensor core and counterweight rotate counterclockwise back to their initial positions. This process is repeated.

Claims

1. A method for using a time-division single-component sensor for borehole seismic detection, characterized in that, The time-division single-component sensor for borehole seismic detection includes: a cylindrical carrier (1); a sensor core (2), which is placed inside the cylindrical carrier and covered by an isolation layer (3); a rotating shaft (4), which is rotatably connected to the cylindrical carrier along the radial direction; a long rod (5), one end of which is fixed to the rotating shaft; a short rod (6), one end of which is fixed to the rotating shaft and forms a 180° angle with the long rod, and the other end of which is fixed to the isolation layer; a counterweight (7), one end of which is fixed to the other end of the long rod, and the weight of the counterweight is less than the sum of the weights of the isolation layer and the sensor core; and an opening slot (8), which is opened on the surface of the cylindrical carrier, and when the long rod is perpendicular to the axial direction of the cylindrical carrier, part of the surface will be exposed outside the opening slot. Torsion spring (9), one end of which is fixed to the inner wall of the cylindrical carrier and the other end is fixed to the rotating shaft; limiting plate (10), which is fixed inside the cylindrical carrier and located below the rotating shaft. When the counterweight contacts the limiting plate, the sensor core is parallel to the axis of the cylindrical carrier; the limiting plate is provided with a magnetic block and the counterweight is provided with magnetic material; the method of use includes the following steps: connecting the cylindrical carrier and the source device to form a borehole seismic probe, using a guide rod to push the borehole seismic probe into the borehole, with the counterweight located above and partially exposed outside the opening slot, and the sensor core located below; when the cylindrical carrier enters the borehole, the part of the counterweight exposed outside the opening slot is pushed to rotate clockwise around the rotating shaft and completely enter the cylindrical carrier, causing the sensor core to rotate clockwise around the rotating shaft, thereby changing the sensitivity direction. When the torque of the torsion spring gradually increases, the thrust on the counterweight disappears, and the sensor core and the counterweight rotate counterclockwise back to the initial position, and so on.

2. The method of using the time-division single-component sensor for borehole seismic detection as described in claim 1, characterized in that, The cylindrical carrier is equipped with a soundproof cover (11), which encloses the sensor core, rotating shaft, long rod, short rod and opening slot.

3. The method of using the time-division single-component sensor for borehole seismic detection as described in claim 2, characterized in that, The inner surface of the soundproof cover is covered with sound-absorbing material.

4. The method of using the time-division single-component sensor for borehole seismic detection as described in claim 1, characterized in that: The portion of the counterweight exposed outside the opening slot is wedge-shaped.

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