In-hole transient electromagnetic advanced detection device and method

Abstract

The invention discloses an in-hole transient electromagnetic advanced detection device and method, a detection head is used for providing a space for rotation of the transient electromagnetic detection device, and a push connection mechanism is used for adjusting the stretching depth of the detection head; the control mechanism is used for controlling rotation of the transient electromagnetic detection device, the z component of the transient electromagnetic detection device can be subjected to rotation detection in different planes through control, and finally-90-+ 90-degree rotation superposition detection of the z component of the transient electromagnetic detection device in multiple planes at each measuring point position in a drill hole is achieved. And correcting a depth coordinate on a certain direction line different from the axial direction of the drill hole in a three-dimensional space to the axial direction of the drill hole by adopting a depth conversion correction formula for the data obtained by rotary superposition, thereby realizing one-to-one correspondence between the apparent resistivity and the rho depth D in the direction of the drill hole, and finally finishing an advanced detection process of 30-50m in front of the drill hole. According to the method, an existing transient electromagnetic detection device can be utilized, so that implementation is facilitated, and the drilling construction amount can be effectively reduced.

Description

Technical Field

[0001] The invention relates to an advance detection technical method, in particular to an in-hole transient electromagnetic advance detection device and method. Background Art

[0002] In tunnel excavation, it is crucial to pre-evaluate the geological conditions ahead, and hydrogeological conditions are an important aspect. There may be water-conducting types such as fault fracture zone water-conducting, collapse column water-conducting, water accumulation in goaf and karst water-rich areas ahead of the excavation. Common means of exploring adverse geological factors include drilling and geophysical exploration. Although drilling has high accuracy, it is costly, time-consuming, and has a limited exploration range. In addition, since multiple detection holes need to be drilled, the detection holes formed are also prone to become channels for hidden water bodies to enter the tunnel, causing secondary accidents. Drilling alone is difficult to meet actual production needs. Geophysical exploration is widely used in water exploration due to its advantages of low cost, large exploration range and rapidity. Although there are many types of geophysical methods, such as seismic reflection wave method, direct current method, electromagnetic method (transient electromagnetic method and radio wave pit penetration), Rayleigh surface wave method, geological radar, radioactive measurement and infrared temperature measurement, most methods are difficult to apply in the excavation working face due to the sensitive characteristics of various methods themselves, the limitation of tunnel excavation space, and external influences such as metal anchor support.

[0003] In summary, conventional transient electromagnetic detection devices on the market can detect boreholes being drilled in tunnels, tunnel heads and working faces with the help of drilling holes, but they are limited to detection around the hole, that is, the length of the borehole is determined by the axial detection depth. In addition, in actual projects, when the geological conditions are poor, the quality of the hole is also poor, and the hole collapse phenomenon is prone to occur, resulting in low actual utilization of the borehole. Therefore, whether it is possible to make full use of the boreholes provided by the construction party, improve the utilization rate of the boreholes, and truly achieve advanced detection based on the length of the borehole is an urgent problem to be solved.

[0004] Therefore, how to provide a new device and method that can not only detect the circumference of the borehole being drilled in the tunnel, the head of the roadway and the working face, but also perform advance detection in front of the borehole head, and finally form an effective detection forecast that is 30 to 50 meters longer than the axial length of the borehole, is the research direction required by the present invention. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides an in-hole transient electromagnetic advance detection device and method, which can effectively solve the above-mentioned technical problems.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an in-hole transient electromagnetic advance detection device, comprising a detection head, a push connection mechanism, a control mechanism and a transient electromagnetic detection device;

[0007] The detection head, the push connection mechanism and the control mechanism are all cylindrical and coaxially connected. A plurality of guide rings I are fixed to the inner wall of the detection head, each guide ring I is penetrated by a push-pull rod I, and each push-pull rod I can move along the axial direction of the detection head. The transient electromagnetic detection device is installed in the detection head, and the transient electromagnetic detection device is movably connected to one end of each push-pull rod I; the transient electromagnetic detection device is used to emit transient electromagnetic signals to the surroundings and receive feedback detection data;

[0008] A plurality of guide rings II are fixed to the inner wall of the push-connection mechanism, each guide ring II is penetrated by a push-pull rod II, so that each push-pull rod II can move along the axial direction of the push-connection mechanism, and one end of each push-pull rod II is coaxially connected to the other end of the corresponding push-pull rod I;

[0009] A plurality of guide rings III are fixed to the inner wall of the control mechanism, each guide ring III is penetrated by a push-pull rod III, and each push-pull rod III can move along the axial direction of the control mechanism, and one end of each push-pull rod III is coaxially connected to the other end of the corresponding push-pull rod II; when a thrust or a pull is applied to the other end of any push-pull rod III, the push-pull rod III can drive the push-pull rod II and the push-pull rod I coaxial therewith, thereby steering the detection direction of the transient electromagnetic detection device. By applying a thrust or a pull to the other end of different push-pull rods III, the steering control of the detection direction of the transient electromagnetic detection device is realized.

[0010] Furthermore, there are four push-pull rods I, II and III, and the push-pull rods I are evenly distributed in the same cross section of the detection head.

[0011] Furthermore, one end of the push-pull rod I is connected to the transient electromagnetic detection device via a universal joint, so that the transient electromagnetic detection device can be driven to rotate when the push-pull rod is pushed or pulled.

[0012] Furthermore, the receiver of the transient electromagnetic detection device is a three-component receiving coil.

[0013] Furthermore, the coaxial push-pull rods I and II, and the push-pull rods II and III are all connected by mortise and tenon joints. This method is convenient for connection and has good stability after connection.

[0014] Furthermore, the push-connection mechanisms are multiple and are coaxially connected, so that a corresponding number of push-connection mechanisms can be selected according to the drilling depth, thereby ensuring stable detection.

[0015] The working method of the above-mentioned in-hole transient electromagnetic advance detection device comprises the following specific steps:

[0016] Step 1: Detection drilling construction: Drill a hole of a certain depth in the required detection direction, and the diameter of the hole is larger than the transient electromagnetic advance detection device, and the hole washing and sweeping work is done to ensure that the transient electromagnetic advance detection device can be extended into the hole;

[0017] Step 2: Plan the measuring points and determine the number of push-connection mechanisms: According to the length of the borehole constructed in step 1, plan the number of measuring points in the borehole and the spacing between adjacent measuring points, and determine the number of push-connection mechanisms according to the length of the borehole;

[0018] Step 3, acquisition of detection data: With the borehole axial direction as the z-axis, the x-axis and y-axis are set perpendicular to each other in the cross section of the borehole to establish an xyz coordinate system, the transient electromagnetic advance detection device is placed in the borehole and extended along the borehole, and the detection head is stopped after it is advanced to the first measuring point. Initially, the three-component receiving coils of the transient electromagnetic detection device are parallel to the x, y and z axes respectively; by pushing and pulling the push-pull rods III of the control mechanism, the transient electromagnetic detection device is driven to turn, so that the transient electromagnetic detection device first rotates in the yz plane with the x-axis as the axis at the measuring point (that is, the z component of the transient electromagnetic detection device is in yz plane), and after completion, the initial position is restored, and then the transient electromagnetic detection device is rotated in the xz plane with the y axis as the axis at the position of the measuring point (that is, the z component of the transient electromagnetic detection device rotates in the xz plane), and during each rotation process, the transient electromagnetic detection device transmits and receives transient electromagnetic detection data to the surrounding in real time, and wirelessly transmits the received detection data to the ground data processing center, thereby completing the detection process of the first measuring point; then the transient electromagnetic advance detection device is advanced to the next measuring point, and the detection process of the first measuring point is repeated at each measuring point until the detection of all measuring points in the borehole is completed;

[0019] Step 4: Obtaining angle information: During the process of rotating detection at each measuring point, the transient electromagnetic detection device records the angle of two rotations of each measuring point;

[0020] Step 5, depth conversion correction: according to the detection data obtained in steps 3 and 4, the three-dimensional apparent resistivity software provided by the transient electromagnetic detection device is used to perform depth inversion. The depth inversion results in that the three-dimensional coordinates of the depth of any point on a line in the three-dimensional space model with the end of the detection head as the reference point in the xyz coordinate system are D(x, y, z). On this line, the apparent resistivity ρ and the depth D correspond one to one. The depth conversion correction formula is used to correct the depth coordinates on a line in a different direction from the borehole axis in the three-dimensional space to the axis of the borehole, that is, the z-axis of the xyz coordinate system, so as to achieve a one-to-one correspondence between the apparent resistivity and the ρ depth D in the borehole direction, and finally complete the advance detection process in front of the borehole.

[0021] Furthermore, the depth conversion correction formula in step 5 is specifically as follows: Assume that the angle of rotation about the x-axis is The angle of rotation about the y-axis is θ; the specific calculation process of the three transformed coordinates is:

[0022]

[0023] Furthermore, the angle range of each rotation in step three is -90° to +90°.

[0024] The innovative principle of the present invention is: conventional borehole transient electromagnetic detection is limited by the borehole, and the length of the hole is limited, and further advance detection is impossible. Moreover, when the conventional borehole transient electromagnetic three-component is received, only the radial anomalies around the hole are detected, that is, only the transient electromagnetic signals of the radial components (X component and Y component) are detected. The same is true for the later imaging, forming an image with the horizontal axis being the borehole length (that is, the probe pushing depth) and the vertical axis being the detection depth. A large amount of information about the inclination and trend of the underground space in the forward-detected axial component Z component is ignored. The present application makes full use of the z component through multi-directional rotation to achieve borehole transient electromagnetic advance detection beyond the borehole length.

[0025] Compared with the prior art, the present invention adopts a combination of a detection head, a push connection mechanism, a control mechanism and a transient electromagnetic detection device. The detection head is used to hold the transient electromagnetic detection device and provide a space for the transient electromagnetic detection device to rotate. The push connection mechanism is used to adjust the insertion depth of the detection head and make the detection head and the control mechanism coaxially connected for subsequent rotation detection. The control mechanism is used to control the rotation of the transient electromagnetic detection device. By controlling, the z component of the transient electromagnetic detection device can be rotated in different planes for detection, and finally realizes the -90° to +90° rotational superposition detection process of the z component of the transient electromagnetic detection device in multiple planes at each measuring point in the borehole. Then, the depth conversion correction formula is used for the data obtained by the rotational superposition, and the depth coordinate on a line in a different direction from the borehole axis in the three-dimensional space is corrected to the axial direction of the borehole, so as to realize the one-to-one correspondence between the apparent resistivity and the ρ depth D in the borehole direction, and finally complete the advance detection process of 30 to 50 m in front of the borehole. The present invention can use the existing transient electromagnetic detection device to realize the advance detection beyond the borehole length, so that it is not only easy to implement, but also can effectively reduce the amount of drilling construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the present invention;

[0027] Figure 2 It is a schematic diagram of the depth conversion correction of the present invention.

[0028] In the figure: 1-transient electromagnetic detection device, 2-push-pull rod, 3-angle measurement tool, 4-upper push-pull rod, 5-lower push-pull rod, 6-left push-pull rod, 7-right push-pull rod. DETAILED DESCRIPTION

[0029] The present invention will be further described below.

[0030] like Figure 1 As shown, a transient electromagnetic advance detection device in a hole includes a detection head, a push connection mechanism, a control mechanism and a transient electromagnetic detection device 1; the receiver of the transient electromagnetic detection device 1 is a three-component receiving coil.

[0031] The detection head, the push connection mechanism and the control mechanism are all cylindrical and coaxially connected. A plurality of guide rings I are fixed to the inner wall of the detection head, each guide ring I is penetrated by a push-pull rod I, and each push-pull rod I can move along the axial direction of the detection head. The transient electromagnetic detection device 1 is installed in the detection head, and the transient electromagnetic detection device 1 is movably connected to one end of each push-pull rod I; the transient electromagnetic detection device 1 is used to transmit transient electromagnetic signals to the surroundings and receive feedback detection data;

[0032] A plurality of guide rings II are fixed to the inner wall of the push-connection mechanism, each guide ring II is penetrated by a push-pull rod II, so that each push-pull rod II can move along the axial direction of the push-connection mechanism, and one end of each push-pull rod II is coaxially connected to the other end of the corresponding push-pull rod I;

[0033] A plurality of guide rings III are fixed to the inner wall of the control mechanism, each guide ring III is penetrated by a push-pull rod III, and each push-pull rod III can move along the axial direction of the control mechanism, and one end of each push-pull rod III is coaxially connected to the other end of the corresponding push-pull rod II; when a thrust or a pull is applied to the other end of any push-pull rod III, the push-pull rod III can drive the push-pull rod II and the push-pull rod I coaxial therewith, thereby steering the detection direction of the transient electromagnetic detection device 1, and by applying a thrust or a pull to the other end of different push-pull rods III, the steering control of the detection direction of the transient electromagnetic detection device 1 is realized;

[0034] There are four push-pull rods I, II and III, and the push-pull rods I are evenly distributed in the same cross section of the detection head. One end of the push-pull rod I is connected to the transient electromagnetic detection device 1 through a universal joint. The coaxial push-pull rods I and II, and the push-pull rods II and III are connected through mortise and tenon joints. There are multiple push-pull connection mechanisms, and the multiple push-pull connection mechanisms are coaxially connected.

[0035] The working method of the above-mentioned in-hole transient electromagnetic advance detection device comprises the following specific steps:

[0036] Step 1: Detection drilling construction: Drill a hole of a certain depth in the required detection direction, and the diameter of the hole should be more than 5mm larger than the diameter of the transient electromagnetic advance detection device. Wash and sweep the hole to ensure that the transient electromagnetic advance detection device can be inserted into the hole.

[0037] Step 2: Plan the measuring points and determine the number of push-connecting mechanisms: According to the length of the borehole constructed in step 1, plan the number of measuring points in the borehole and the spacing between adjacent measuring points, and determine the number of push-connecting mechanisms based on the length of the borehole.

[0038] Step 3, acquisition of detection data: an xyz coordinate system is established with the borehole axial direction as the z axis and the x and y axes being perpendicular to each other in the cross section of the borehole, a transient electromagnetic advance detection device is placed in the borehole and extended along the borehole, and the detection head is stopped when it is advanced to the first measuring point. Initially, the three-component receiving coils (i.e., the x component, the y component, and the z component) of the transient electromagnetic detection device are parallel to the x, y, and z axes respectively; by pushing and pulling the push-pull rods III with different control mechanisms, the transient electromagnetic detection device 1 is driven to turn, and the four push-pull rods III are specifically divided, and the two push-pull rods III on the y axis are determined as the upper push-pull rod 4 and the lower push-pull rod 5 according to the position relationship, and the two push-pull rods III on the x axis are determined as the left push-pull rod 6 and the right push-pull rod 7 according to the position relationship, and the left push-pull rod 6 and the right push-pull rod 7 are kept stationary, and the transient electromagnetic detection device 1 is first rotated in the yz plane with the x axis as the axis at the measuring point by synchronously pushing or pulling the upper push-pull rod 4 and pulling or pushing the lower push-pull rod 5. The transient electromagnetic detection device 1 rotates in the xz plane with the y axis as the axis by synchronously pushing or pulling the left push-pull rod 6 and pulling or pushing the right push-pull rod 7. The angle range of each rotation of the transient electromagnetic detection device 1 is -90° to +90°; and during each rotation, the transient electromagnetic detection device 1 transmits and receives transient electromagnetic detection data to the surrounding in real time, and wirelessly transmits the received detection data to the ground data processing center, so that the transient electromagnetic detection device 1 completes the multi-plane rotation superposition detection process of -90° to +90° of the axial z component of the first measuring point; then the transient electromagnetic advance detection device is advanced to the next measuring point, and each measuring point repeats the detection process of the first measuring point until the detection of all measuring points in the borehole is completed.

[0039] Step 4: Obtaining angle information: When the transient electromagnetic detection device 1 performs rotation detection at each measuring point, the angle measurement tool 3 is used to record the angle of two rotations of each measuring point.

[0040] Step 5, depth conversion correction: according to the detection data obtained in steps 3 and 4, the three-dimensional apparent resistivity software provided by the transient electromagnetic detection device 1 is used to perform depth inversion. The depth inversion results in that the three-dimensional coordinates of the depth of any point on a line in the three-dimensional space model with the end of the detection head as the reference point in the xyz coordinate system are D (x, y, z). On this line, the apparent resistivity ρ and the depth D correspond one to one. The depth conversion correction formula is used to correct the depth coordinates on a line in a different direction from the borehole axis in the three-dimensional space to the axial direction of the borehole, that is, the z-axis of the xyz coordinate system, so as to achieve a one-to-one correspondence between the apparent resistivity and the ρ depth D in the borehole direction, as shown in FIG. Figure 2 As shown, specifically: Assume that the angle of rotation around the x-axis is The angle of rotation about the y-axis is θ; the specific calculation process of the three transformed coordinates is:

[0041]

[0042] Finally, the advance detection process of 30 to 50 meters ahead of the borehole is completed.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A transient electromagnetic advance detection device in a hole, characterized in that: It includes a detection head, a push connection mechanism, a control mechanism and a transient electromagnetic detection device; The detection head, the push connection mechanism and the control mechanism are all cylindrical and coaxially connected. A plurality of guide rings I are fixed to the inner wall of the detection head, each guide ring I is penetrated by a push-pull rod I, and each push-pull rod I can move along the axial direction of the detection head. The transient electromagnetic detection device is installed in the detection head, and the transient electromagnetic detection device is movably connected to one end of each push-pull rod I; the transient electromagnetic detection device is used to emit transient electromagnetic signals to the surroundings and receive feedback detection data; A plurality of guide rings II are fixed to the inner wall of the push-connection mechanism, each guide ring II is penetrated by a push-pull rod II, so that each push-pull rod II can move along the axial direction of the push-connection mechanism, and one end of each push-pull rod II is coaxially connected to the other end of the corresponding push-pull rod I; A plurality of guide rings III are fixed to the inner wall of the control mechanism, each guide ring III is penetrated by a push-pull rod III, and each push-pull rod III can move along the axial direction of the control mechanism, and one end of each push-pull rod III is coaxially connected to the other end of the corresponding push-pull rod II; when a thrust or a pull is applied to the other end of any push-pull rod III, the push-pull rod III can drive the push-pull rod II and the push-pull rod I coaxial therewith, thereby steering the detection direction of the transient electromagnetic detection device. By applying a thrust or a pull to the other end of different push-pull rods III, the steering control of the detection direction of the transient electromagnetic detection device is realized.

2. The in-hole transient electromagnetic advance detection device according to claim 1 is characterized in that: There are four push-pull rods I, II and III, and the push-pull rods I are evenly distributed in the same cross section of the detection head.

3. The in-hole transient electromagnetic advance detection device according to claim 1 is characterized in that: One end of the push-pull rod I is connected to the transient electromagnetic detection device through a universal joint.

4. The in-hole transient electromagnetic advance detection device according to claim 1 is characterized in that: The receiver of the transient electromagnetic detection device is a three-component receiving coil.

5. The in-hole transient electromagnetic advance detection device according to claim 1 is characterized in that: The coaxial push-pull rods I and II, as well as the push-pull rods II and III are all connected through mortise and tenon joints.

6. The in-hole transient electromagnetic advance detection device according to claim 1, characterized in that: There are multiple push-connecting mechanisms, and the multiple push-connecting mechanisms are coaxially connected.

7. A method for operating the in-hole transient electromagnetic advance detection device according to claim 1, characterized in that: The specific steps are: Step 1: Detection drilling construction: Drill a hole of a certain depth in the required detection direction, and the diameter of the hole is larger than the transient electromagnetic advance detection device, and the hole washing and sweeping work is done to ensure that the transient electromagnetic advance detection device can be extended into the hole; Step 2: Plan the measuring points and determine the number of push-connection mechanisms: According to the length of the borehole constructed in step 1, plan the number of measuring points in the borehole and the spacing between adjacent measuring points, and determine the number of push-connection mechanisms according to the length of the borehole; Step 3, acquisition of detection data: with the borehole axial direction as the z axis, the x axis and the y axis are set perpendicular to each other in the cross section of the borehole to establish an xyz coordinate system, the transient electromagnetic advance detection device is placed in the borehole and extended along the borehole, and the detection head stops advancing when it is advanced to the first measuring point. Initially, the three-component receiving coils of the transient electromagnetic detection device are parallel to the x, y and z axes respectively; by pushing and pulling the push-pull rods III of the control mechanism, the transient electromagnetic detection device is driven to turn, so that the transient electromagnetic detection device rotates in the yz plane with the x axis as the axis at the measuring point, and then restores the initial position after completion, and then the transient electromagnetic detection device rotates in the xz plane with the y axis as the axis at the measuring point, and during each rotation, the transient electromagnetic detection device transmits and receives transient electromagnetic detection data to the surrounding in real time, and wirelessly transmits the received detection data to the ground data processing center, thereby completing the detection process of the first measuring point; then the transient electromagnetic advance detection device is advanced to the next measuring point, and each measuring point repeats the detection process of the first measuring point until the detection of all measuring points in the borehole is completed; Step 4: Obtaining angle information: During the process of rotating detection at each measuring point, the transient electromagnetic detection device records the angle of two rotations of each measuring point; Step 5, depth conversion correction: according to the detection data obtained in steps 3 and 4, the three-dimensional apparent resistivity software provided by the transient electromagnetic detection device is used to perform depth inversion. The depth inversion results in that the three-dimensional coordinates of the depth of any point on a line in the three-dimensional space model with the end of the detection head as the reference point in the xyz coordinate system are D(x, y, z). On this line, the apparent resistivity ρ and the depth D correspond one to one. The depth conversion correction formula is used to correct the depth coordinates on a line in a different direction from the borehole axis in the three-dimensional space to the axis of the borehole, that is, the z-axis of the xyz coordinate system, so as to achieve a one-to-one correspondence between the apparent resistivity and the ρ depth D in the borehole direction, and finally complete the advance detection process in front of the borehole.

8. The working method according to claim 7, characterized in that: The depth conversion correction formula in step 5 is specifically: Assume that the angle of rotation around the x-axis is The angle of rotation about the y-axis is θ; the specific calculation process of the three transformed coordinates is:

9. The working method according to claim 7, characterized in that: The angle range of each rotation in step 3 is -90° to +90°.

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