Magnetotelluric field geophysical prospecting method and device

Abstract

The invention belongs to the technical field of electromagnetic geophysical prospecting equipment, and particularly relates to a magnetotelluric field geophysical prospecting method and device. The embedded magnetic bar further comprises a splicing structure, the splicing structure is matched with the installation frame, and the splicing structure is used for reducing the probability that the magnetic bar inclines after being embedded. By arranging the splicing structure, when the magnetic bar is installed, on one hand, after the installation frame is fixed, the assembling ring is guided through the assembling groove, the assembling ring and the magnetic bar are lifted to the position close to the ground for horizontal adjustment, and compared with horizontal adjustment at the bottom of a pit groove, the controllable space is increased, and the adjustment difficulty is reduced; and on the other hand, the shape of the area where the magnetic bars are buried is standardized, splicing type filling of the buried grooves is achieved in cooperation with splicing blocks manufactured outside the pit grooves in a punning mode, it is guaranteed that the magnetic bars are effectively separated from ground electromagnetic waves through the soil layer, meanwhile, compaction operation is not needed for backfilling, and then the probability that the soil layer at the positions where the magnetic bars and the mounting frame are located settles is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic geophysical exploration equipment, and specifically relates to a magnetotelluric prospecting method and device. Background Art

[0002] MT exploration, namely magnetotelluric sounding method, is a geophysical exploration method that uses natural alternating electromagnetic fields to study the electrical structure of the earth.

[0003] In MT exploration technology, the main function of the magnetic rod is to act as a magnetic field sensor for measuring the magnetic field component of the earth's natural electromagnetic field. The presence of the magnetic rod can not only combine magnetic field data with electric field data through accurate measurement of the magnetic field component, but also the multi-directional magnetic field data provided by the magnetic rod can support more complex three-dimensional inversion calculations to more accurately infer the underground electrical structure. In order to ensure the stability of the magnetic rod performance and reduce the interference of ground electromagnetic signals, the magnetic rod is usually buried underground in a horizontal or vertical manner and isolated from the outside by backfilling the soil. During the backfilling process, since the backfill soil needs to be compacted, during the backfilling and compaction process, due to soil settlement, it is easy to cause the magnetic rod to deviate from the horizontal or vertical state, especially the installation of the horizontal magnetic rod. Because there is no observation channel after backfilling, it is impossible to confirm whether the magnetic rod is in a horizontal state. Therefore, during long-term detection, it is easy to cause the probability of measurement data distortion.

[0004] In the related art, in order to enhance the stability of the magnetic rod installation, an application with the application number CN2024101817367 and the name of the device for fixing the magnetic rod in geophysical magnetotelluric exploration is disclosed. In this solution, the two ends of the magnetic rod are clamped by a support structure to reduce the impact on the magnetic rod during soil backfilling. However, it is found during actual observation that on the one hand, during soil backfilling and compaction, it is easy for the magnetic rod and the support structure to settle together, and on the other hand, due to the narrow underground space, it is not convenient to adjust the horizontal state of the magnetic rod.

[0005] In view of this, the present invention proposes a magnetotelluric prospecting method and device to solve the above technical problems. Summary of the Invention

[0006] In order to make up for the deficiencies of the prior art and solve the above technical problems, the present invention proposes a magnetotelluric prospecting method and device.

[0007] The technical solution adopted by the present invention to solve its technical problems is a magnetotelluric prospecting device, including an installation frame and a magnetic rod. The installation frame and the magnetic rod are both buried underground, and the magnetic rod is installed on the installation frame;

[0008] It further includes a splicing structure, which cooperates with the installation frame and is used to reduce the probability of the magnetic rod tilting after being buried;

[0009] The splicing structure includes a ground burial groove, an assembly ring, a shaping layer and a splicing block;

[0010] The ground burial groove is opened on the ground, and the installation frame is fixedly installed in the ground burial groove;

[0011] The inner cavity of the installation frame forms an assembly groove, the assembly groove is open at the top of the installation frame, the assembly ring is slidably installed in the assembly groove, and the magnetic rod is installed on the assembly ring through a fine-tuning mechanism;

[0012] The shaping layer is composed of small-particle loose soil, the shaping layer is located at the bottom of the assembly groove, and the shaping layer wraps the assembly ring and the magnetic rod;

[0013] The splicing block is a high-density plate-like structure formed by pressing soil, the splicing block is installed above the shaping layer, and the splicing block and the plastic layer are used to fill the assembly groove.

[0014] Preferably, the fine-tuning mechanism is used to adjust the relative angle between the magnetic rod and the assembly ring, and the fine-tuning mechanism includes an installation ring, an adjustment rod and a support spring;

[0015] Symmetrically arranged installation rings are fixedly installed on the assembly ring, an adjustment rod is rotatably installed on the installation rings together, an installation groove is opened in the middle of the adjustment rod, and the magnetic rod is detachably fixedly installed in the installation groove;

[0016] Adjustment grooves are opened on the installation ring, the adjustment grooves are all arc-shaped, an adjustment bolt is threadedly installed on the installation ring, the adjustment bolt extends into the adjustment groove, a top piece is fixedly installed on the adjustment rod, and the top piece is located on the movement path of the adjustment bolt;

[0017] A support spring is fixedly installed at the bottom of the adjustment groove, and the support spring abuts against the bottom of the top piece.

[0018] Preferably, the ground burial groove and the installation frame are of matching dimensions, the installation frame is inlaid and installed in the ground burial groove, and the soil outside the ground burial groove is all compacted.

[0019] Preferably, it further includes a shaping mechanism, which cooperates with the installation frame and is used to shape the ground burial groove. The shaping mechanism includes a pressing plate and a baffle;

[0020] The pressing plate has the same shape as the bottom surface of the assembly groove, the baffles are designed in plural, a plurality of the baffles correspond to the inner wall of the assembly groove one by one, the baffles are installed on the pressing plate, and in the initial state, the baffles and the pressing plate cooperate to separate the assembly groove from the ground burial groove.

[0021] Preferably, the baffle is hinged to the pressing plate. The inclined surfaces are arranged on the mutually approaching sides of two adjacent baffles. The baffle and the pressing plate cooperate to form a cylindrical structure with an open top. The top of the installation frame is fixedly installed with uniformly distributed limiting blocks. When the baffle and the pressing plate are in the same horizontal plane, the limiting blocks are located between two adjacent baffles.

[0022] Preferably, the shaping mechanism further includes a bearing film bag, which is a film structure made of plastic film. The cylindrical structure formed by the baffle and the pressing plate is matched with the bearing film bag. The bearing film bag cooperates with the baffle and the pressing plate to manufacture splicing blocks.

[0023] Preferably, a plurality of penetration holes are formed in the bearing film bag. The bearing film bag cooperates with the penetration holes to irrigate brine into the buried groove.

[0024] Preferably, a plurality of extension grooves are formed in the installation frame. The extension grooves are all parallel to the bottom surface of the assembly groove. Extension rods are hermetically installed in the extension grooves. A pressurization groove is formed at the top of the installation frame. A threaded rod is rotatably installed in the pressurization groove. A sealing plate is slidably installed in the pressurization groove. The sealing plate is in screw drive connection with the threaded rod. The pressurization groove is connected to the extension groove through a pipeline. Hydraulic oil is filled in both the pressurization groove and the extension groove.

[0025] Preferably, a telescopic groove is formed in the installation frame. The telescopic groove is communicated with both the pressurization groove and the assembly groove. A push rod is elastically installed in the telescopic groove through a spring. The telescopic groove and the push rod are both designed in a T shape. The push rod is aligned with the top end of the threaded rod. Uniformly distributed grooves are formed at the top end of the threaded rod. In the initial state, the push rod extends into the groove. When the threaded rod rotates, the push rod is pushed to extend into the assembly groove.

[0026] A magnetotelluric geophysical prospecting method, which includes the following steps:

[0027] S1: Dig a groove on the pre-demarcated ground, lower the installation frame into the groove, and synchronously install the pressing plate and the baffle in the assembly groove;

[0028] S2: Backfill the soil to the outside of the installation frame and synchronously carry out compaction treatment until the soil is flush with the ground, and then take out the pressing plate and the baffle;

[0029] S3: Backfill part of the soil into the assembly groove and tamp the soil. Then rotate the threaded rod to cause the push rod to extend into the assembly groove;

[0030] S4: Install the assembly ring in the assembly groove and be blocked by the push rod. Turn the adjusting bolt and, with the assistance of the bubble level on the magnetic rod, make the magnetic rod horizontal;

[0031] S5: Take out the assembly ring and the magnetic rod, filter the soil and backfill it into the assembly groove, and install the assembly ring and the magnetic rod in the middle of the backfilled soil to form a shaping layer;

[0032] S6: Place the soil in the load-bearing membrane bag and put it into the cylindrical structure formed by the baffle and the pressing plate. After ramming treatment, the splicing block is made;

[0033] S7: Place the load-bearing membrane bag and the splicing block in the assembly groove, then place the unfolded baffle and pressing plate on the installation frame, and then connect the magnetic rod connecting wire to the test instrument.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. For the geoelectric magnetic field geophysical exploration method and device of the present invention, by setting the splicing structure, when installing the magnetic rod, on the one hand, after fixing the installation frame, the assembly groove is used to guide the assembly ring, and the assembly ring and the magnetic rod are lifted to a position close to the ground for horizontal adjustment. Compared with horizontal adjustment at the bottom of the pit, the controllable space is increased, and the adjustment difficulty is reduced. On the other hand, by standardizing the shape of the area where the magnetic rod is buried and cooperating with the splicing blocks made by ramming outside the pit, the splicing filling of the buried groove is realized. While ensuring that the soil layer effectively separates the magnetic rod from the ground electromagnetic wave, backfilling does not require compaction operation, thereby reducing the probability of settlement of the soil layer where the magnetic rod and the installation frame are located and maintaining the horizontal state of the magnetic rod.

[0036] 2. For the geoelectric magnetic field geophysical exploration method and device of the present invention, the excavated soil is backfilled to the outside of the installation frame and the soil is compacted. On the one hand, the soil will wrap the outer wall of the installation frame, causing the installation frame to be embedded in the inner wall of the buried groove. On the other hand, the density of the soil layer around the installation frame will increase. The combination of the two will effectively reduce the probability of the installation frame moving. Especially during the installation of the magnetic rod, it can effectively avoid the probability of settlement of the soil layer around the installation frame caused by operations such as manual walking and soil backfilling. Therefore, after the initial leveling of the magnetic rod, its horizontal state can be maintained for a long time. Brief Description of the Drawings

[0037] The present invention will be further described below with reference to the accompanying drawings.

[0038] Figure 1 is the underground burial schematic of the present invention;

[0039] Figure 2 is the lateral schematic of the present invention;

[0040] Figure 3 is the three-dimensional assembly drawing of the pressing plate and the baffle in the assembly groove;

[0041] Figure 4It is a three-dimensional assembly drawing of the pressing plate and the baffle plate at the top of the installation frame;

[0042] Figure 5 It is a three-dimensional assembly drawing of the assembly ring, the magnetic rod and the installation frame;

[0043] Figure 6 It is a three-dimensional drawing of the fine-tuning mechanism;

[0044] Figure 7 It is an internal structure drawing of the installation frame;

[0045] Figure 8 It is Figure 7 The partial enlarged view at position A in

[0046] Figure 9 It is a three-dimensional drawing of the load-bearing membrane bag;

[0047] Figure 10 It is the method flow chart of the present invention;

[0048] In the figure: 1. Installation frame; 2. Buried trench; 21. Assembly groove; 22. Assembly ring; 23. Shaping layer; 24. Splicing block; 3. Installation ring; 31. Adjusting rod; 32. Installation groove; 33. Adjusting groove; 34. Adjusting bolt; 35. Top piece; 36. Support spring; 4. Pressing plate; 41. Baffle plate; 42. Limit block; 5. Load-bearing membrane bag; 51. Penetration hole; 6. Extension groove; 61. Extension insertion rod; 62. Pressurization groove; 63. Threaded rod; 64. Sealing plate; 65. Telescopic groove; 66. Thrust rod; 67. Groove; 7. Magnetic rod. Detailed implementation manners

[0049] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific implementation manners.

[0050] As Figures 1 to 9 shown, a geoelectric magnetic field geophysical exploration device according to the present invention includes an installation frame 1 and a magnetic rod 7. The installation frame 1 and the magnetic rod 7 are both buried underground, and the magnetic rod 7 is installed on the installation frame 1;

[0051] It further includes a splicing structure, the splicing structure is matched with the installation frame 1, and the splicing structure is used to reduce the probability of the magnetic rod 7 tilting after being buried;

[0052] The splicing structure includes a buried trench 2, an assembly ring 22, a shaping layer 23 and a splicing block 24;

[0053] The buried trench 2 is opened on the ground, the installation frame 1 is fixedly installed in the buried trench 2, and the buried trench 2 is dug and trimmed manually;

[0054] The inner cavity of the installation frame 1 forms an assembly groove 21. The assembly groove 21 is open at the top of the installation frame 1. The assembly ring 22 is slidably installed in the assembly groove 21. The magnetic rod 7 is installed on the assembly ring 22 through a fine-tuning mechanism. In the present invention, the installation frame 1 is a rectangular frame structure composed of vertical rods and crossbars. The inner cavity of the installation frame 1 forms the assembly groove 21. The assembly groove 21 is a vertical groove, and the sides are perpendicular to the bottom surface. The assembly ring 22 is a rectangular ring, and the assembly ring 22 has the same size as the assembly groove 21. The assembly groove 21 can guide the assembly ring 22, causing the assembly ring 22 to move parallel in the height direction of the assembly groove 21. Therefore, when the installation frame 1 is fixed, when the assembly ring 22 is at the top position of the assembly groove 21, if the magnetic rod 7 is in a horizontal state, since the assembly ring 22 moves parallel in the height direction of the assembly groove 21 in the assembly groove 21, after the assembly ring 22 descends to the bottom of the assembly groove 21, the magnetic rod 7 is still in a horizontal position;

[0055] The shaping layer 23 is composed of small-particle loose soil. The shaping layer 23 is located at the bottom of the assembly groove 21. The shaping layer 23 wraps the assembly ring 22 and the magnetic rod 7. The soil that constitutes the shaping layer 23 is obtained by screening the excavated soil. When the plastic layer is formed, it is necessary to first manually sprinkle a layer of soil into the installation frame 1 to fill the gap between the installation frame 1 and the bottom of the buried groove 2 with the soil. Then, place the assembly ring 22 installed with the magnetic rod 7. Finally, sprinkle another layer of small-particle loose soil above the magnetic rod 7. It should be noted that when filling the two layers of soil, the thickness of the two layers of soil needs to be greater than the radius of the magnetic rod 7. When the included angle between the magnetic rod 7 and the assembly ring 22 is relatively large, the thickness of the two layers of soil needs to be greater than the diameter of the magnetic rod 7 to facilitate the shaping layer 23 to completely cover the magnetic rod 7;

[0056] The splicing block 24 is a high-density plate-like structure formed by pressing soil. The splicing block 24 is installed above the shaping layer 23. The splicing block 24 and the plastic layer are used to fill the assembly groove 21. After the excavated soil is screened, after removing the part used to shape the shaping layer 23, a part of the remaining soil is tamped in a mold to manufacture the splicing block 24. When manufacturing the splicing block 24, it is necessary to pay attention to making the size of the splicing block 24 match the assembly groove 21.

[0057] The buried groove 2 matches the size of the installation frame 1. The installation frame 1 is inlaid and installed in the buried groove 2. The soil outside the buried groove 2 is all compacted.

[0058] In the geophysical exploration technology of magnetotelluric field, the horizontal burial of the magnetic rod 7 has a significant impact on the detection accuracy and detection effect of the magnetic field. The method of first burying and then backfilling and pressing the soil has a probability of causing uneven settlement of the magnetic rod 7 because it is not easy to control the uniformity of the force during backfilling and pressing, resulting in the magnetic rod 7 that was leveled during installation tilting again. To improve this situation, a splicing mechanism is set in the present invention. After the magnetic rod 7 is installed underground, it is not necessary to press and tamp the soil too much, and the magnetic rod 7 can be isolated from the ground environment by using relatively dense soil.

[0059] Specifically, when horizontally burying the magnetic rod 7, the staff first locates the installation position according to GPS and installation requirements. After the installation position is determined, equipment such as a digging shovel is used to assist in digging a pit at the installation position. During the digging, the depth of the pit needs to be greater than 30 cm. After the pit is dug, the installation frame 1 is placed in the pit, and the staff manually adjusts the installation frame 1 to make it approximately vertical, minimizing the gap between the top surface of the installation frame 1 and the horizontal plane. Subsequently, the excavated soil is backfilled outside the installation frame 1. It should be noted that during backfilling, soil entry into the assembly groove 21 needs to be avoided. After the soil backfilling is completed, the soil layer outside the installation frame 1 is compacted by tamping, and during the tamping process, attention should be paid to making the ground level with the top end of the installation frame 1. Then, the assembly ring 22 is placed in the assembly groove 21, and the levelling mechanism is used to adjust the levelness of the magnetic rod 7. After the adjustment is completed, the assembly ring 22 and the magnetic rod 7 are taken out, and small-particle soil is filled into the assembly groove 21. After filling to a certain thickness, the assembly ring 22 and the magnetic rod 7 are placed downward through the assembly groove 21, and a small force is applied to the magnetic rod 7 and the assembly ring 22. During the pressing, the bubble level on the magnetic rod 7 needs to be constantly monitored to prevent the magnetic rod 7 from deviating from the horizontal plane. At the same time, the connecting wire at the end of the magnetic rod 7 needs to be pulled out of the assembly groove 21 to facilitate subsequent connection of the magnetic rod 7 to the testing instrument using the connecting wire. When the bottoms of the magnetic rod 7 and the assembly ring 22 are in contact with the soil, small-particle soil is filled into the assembly groove 21 again to completely cover the magnetic rod 7 and the assembly ring 22, forming a shaping layer 23 that wraps the magnetic rod 7. After slightly leveling the top of the shaping layer 23, the splicing block 24 formed by tamping and pressing is directly placed in the assembly groove 21. Under the action of gravity, the splicing block 24 fits with the plastic layer and seals the assembly groove 21, thus completing the horizontal burial of the magnetic rod 7.

[0060] In the present invention, by providing a splicing structure, when installing the magnetic rod 7, on the one hand, after fixing the installation frame 1, the assembly groove 21 is used to guide the assembly ring 22, and the assembly ring 22 and the magnetic rod 7 are lifted to a position close to the ground for horizontal adjustment. Compared with horizontal adjustment at the bottom of the pit groove, the manipulable space is increased, and the adjustment difficulty is reduced. On the other hand, by standardizing the shape of the area where the magnetic rod 7 is buried and cooperating with the splicing block 24 manufactured by ramming outside the pit groove, the splicing filling of the buried groove 2 is realized. While ensuring that the soil layer effectively separates the magnetic rod 7 from the ground electromagnetic wave, backfilling does not require compaction operation, thereby reducing the probability of settlement of the soil layer where the magnetic rod 7 and the installation frame 1 are located and maintaining the horizontal state of the magnetic rod 7.

[0061] As a preferred embodiment of the present invention, the fine-tuning mechanism is used to adjust the relative angle between the magnetic rod 7 and the assembly ring 22. The fine-tuning mechanism includes an installation ring 3, an adjustment rod 31 and a support spring 36;

[0062] Symmetrically arranged installation rings 3 are fixedly installed on the assembly ring 22. An adjustment rod 31 is rotatably installed on the installation rings 3 together. An installation groove 32 is formed in the middle of the adjustment rod 31. The magnetic rod 7 is detachably and fixedly installed in the installation groove 32. In the present invention, the magnetic rod 7 is a cylindrical structure, and its middle part is installed in the installation groove 32. When the adjustment rod 31 rotates, the magnetic rod 7 will rotate. When the axis direction of the magnetic rod 7 is parallel to the horizontal direction, the horizontal adjustment of the magnetic rod 7 is realized;

[0063] An adjustment groove 33 is formed in one of the installation rings 3. The adjustment groove 33 is arc-shaped. An adjustment bolt 34 is threadedly installed on the installation ring 3. The adjustment bolt 34 extends into the adjustment groove 33. A top piece 35 is fixedly installed on the adjustment rod 31. The top piece 35 is located on the movement path of the adjustment bolt 34;

[0064] A support spring 36 is fixedly installed at the bottom of the adjustment groove 33. The support spring 36 abuts against the bottom of the top piece 35.

[0065] When adjusting the level of the magnetic rod 7, a worker pulls the assembly ring 22 with one hand, causing the assembly ring 22 to stay near the ground in the assembly groove 21, and turns the adjustment bolt 34 with a screwdriver with the other hand. Since the adjustment bolt 34 is threadedly connected to the installation ring 3, as the adjustment bolt 34 rotates, the adjustment bolt 34 gradually extends into or withdraws from the adjustment groove 33. The top piece 35 fixed on the adjustment rod 31 abuts against the support spring 36 and the adjustment bolt 34 on both sides respectively. Therefore, as the adjustment bolt 34 moves, the top piece 35 and the adjustment rod 31 can be made to rotate around the central axis of the adjustment groove 33, thereby realizing the adjustment of the angle of the magnetic rod 7.

[0066] As a preferred embodiment of the present invention, it further includes a shaping mechanism, which cooperates with the installation frame 1 and is used to shape the shape of the buried groove 2. The shaping mechanism includes a pressing plate 4 and a baffle 41;

[0067] The pressing plate 4 has the same shape as the bottom surface of the assembly groove 21. The baffles 41 are designed in plurality, and a plurality of the baffles 41 correspond to the inner wall of the assembly groove 21 one by one. The baffles 41 are installed on the pressing plate 4. In the initial state, the baffles 41 and the pressing plate 4 cooperate to separate the assembly groove 21 from the buried groove 2. When excavating and trimming the buried groove 2, the staff inserts the baffles 41 and the pressing plate 4 into the assembly groove 21. Under the guiding action of the assembly groove 21, the pressing plate 4 and the baffles 41 move along the height direction of the assembly groove 21. In the present invention, a handle is fixedly installed at one end of the baffle 41 away from the pressing plate 4, which is convenient for the staff to hold. By pushing the baffle 41, the pressing plate 4 can be driven to lift and lower in the assembly groove 21. Before installing the magnetic ring, by pushing the baffle 41 and the pressing plate 4 and hitting the bottom of the assembly groove 21, the bottom of the buried groove 2 can be effectively tamped. After tamping, the bottom of the buried groove 2 tends to be flat. Then, the baffles 41 and the pressing plate 4 are completely inserted into the assembly groove 21. The baffles 41 and the pressing plate 4 will separate the assembly groove 21 from the buried groove 2. At this time, the excavated soil is backfilled to the outside of the installation frame 1 and the soil is compacted. On the one hand, the soil will wrap the outer wall of the installation frame 1, causing the installation frame 1 to be embedded on the inner wall of the buried groove 2. On the other hand, the soil layer density around the installation frame 1 will increase. The combination of the two will effectively reduce the probability of the installation frame 1 moving. Especially during the installation of the magnetic rod 7, it can effectively avoid the probability of the soil layer settlement around the installation frame 1 caused by operations such as manual walking and soil backfilling. Furthermore, after the magnetic rod 7 is initially leveled, its horizontal state can be maintained for a long time.

[0068] The baffle 41 is hinged to the pressing plate 4. The inclined surfaces are arranged on the mutually approaching sides of two adjacent baffles 41. The baffle 41 and the pressing plate 4 cooperate to form a cylindrical structure with an open top. The shape setting of the baffle 41 enables the baffle 41 to cooperate with the pressing plate 4 to form a cylindrical structure with stable dimensions in the assembly groove 21. When the baffle 41 and the pressing plate 4 are separated from the assembly groove 21, in order to maintain its shape, a steel wire or a telescopic baffle 41 can be used to bind the periphery. Uniformly distributed limit blocks 42 are fixedly installed at the top of the installation frame 1. When the baffle 41 and the pressing plate 4 are in the same horizontal plane, the limit blocks 42 are located between two adjacent baffles 41.

[0069] The presence of the baffle 41 and the pressing plate 4 can be used not only to facilitate the trimming of the buried groove 2, but also to manufacture the splicing block 24. Since the tubular structure with an open top formed by the pressing plate 4 and the baffle 41 is more consistent with the size and shape of the assembly groove 21, a baffle 41 with a smaller thickness is preferably selected. After combining the baffle 41 and the pressing plate 4, they are used to compact and manufacture the splicing block 24. After the splicing block 24 is shaped, the restraint around the periphery of the multiple baffles 41 is removed. At this time, the baffle 41 and the pressing plate 4 rotate relative to each other to realize the demolding of the splicing block 24. After the splicing block 24 is filled into the assembly groove 21, in order to prevent the settlement of the installation frame 1 caused by accidental trampling by personnel, the staff spreads the unfolded baffle 41 and pressing plate 4 on the top of the installation frame 1 and uses the limit block 42 to limit them. When necessary, marks can also be sprayed on the baffle 41 or the pressing plate 4, thereby reducing the probability of personnel trampling on the ground near the installation frame 1, and thus maintaining the level of the magnetic rod 7.

[0070] As a preferred embodiment of the present invention, the shaping mechanism further includes a load-bearing membrane bag 5. The load-bearing membrane bag 5 is a membranous structure made of plastic film. The tubular structure formed by the baffle 41 and the pressing plate 4 is matched with the load-bearing membrane bag 5, and the load-bearing membrane bag 5 cooperates with the baffle 41 and the pressing plate 4 to manufacture the splicing block 24.

[0071] A plurality of permeation holes 51 are formed in the load-bearing membrane bag 5. The load-bearing membrane bag 5 cooperates with the permeation holes 51 to pour brine into the buried groove 2.

[0072] The presence of the load-bearing membrane bag 5 not only reduces the demolding efficiency of the splicing block 24 when shaping the splicing block 24, but also facilitates the movement of the splicing block 24. After the splicing block 24 is filled into the assembly groove 21, when the magnetic rod 7 needs to be inspected later, the difficulty of removing the splicing block 24 can be reduced by lifting the load-bearing membrane bag 5. The arrangement of the permeation holes 51 formed in the load-bearing membrane bag 5 enables brine to be poured into the load-bearing membrane bag 5 after the splicing block 24 is filled. The brine permeates from the periphery of the splicing block 24 into the assembly groove 21 and the buried groove 2. On the one hand, the brine entraps the soil to fill the gaps between the buried groove 2 and the assembly groove 21. On the other hand, the brine itself also has the function of reducing the impedance between the magnetic rod 7 and the environment.

[0073] As a preferred embodiment of the present invention, a plurality of extension grooves 6 are formed in the installation frame 1. The extension grooves 6 are all parallel to the bottom surface of the assembly groove 21. Extension insertion rods 61 are hermetically installed in the extension grooves 6. A pressurization groove 62 is formed at the top end of the installation frame 1. A threaded rod 63 is rotatably installed in the pressurization groove 62. A sealing plate 64 is slidably installed in the pressurization groove 62. In the present invention, the top end of the pressurization groove 62 is circular, which facilitates the rotation of the top end of the threaded rod 63. The sliding part of the sealing plate 64 is set as an incomplete circle, so that the sealing plate 64 cannot rotate around the threaded rod 63. The sealing plate 64 is in screw drive connection with the threaded rod 63. The pressurization groove 62 and the extension groove 6 are connected by a pipeline. Hydraulic oil is filled in both the pressurization groove 62 and the extension groove 6. In order to further enhance the stability of the installation frame 1 after installation, after the installation frame 1 is placed in the buried groove 2 and before the buried groove 2 is trimmed, the staff manually turns the threaded rod 63. Under the principle of screw drive, the sealing plate 64 changes from rotation to linear motion. The sealing plate 64 presses the hydraulic oil in the pressurization groove 62, causing the hydraulic oil to flow into the extension groove 6 and pushing the extension insertion rod 61 to move outwards. The extension insertion rod 61 gradually inserts into the soil layer to realize the preliminary fixation of the installation frame 1.

[0074] A telescopic groove 65 is formed in the installation frame 1. The telescopic groove 65 is communicated with both the pressurization groove 62 and the assembly groove 21. A top rod 66 is elastically installed in the telescopic groove 65 through a spring. The telescopic groove 65 and the top rod 66 are both designed in a T shape. The top rod 66 is aligned with the top end of the threaded rod 63. Uniformly distributed grooves 67 are formed at the top end of the threaded rod 63. In the initial state, the top rod 66 extends into the grooves 67. When the threaded rod 63 rotates, it pushes the top rod 66 to extend into the assembly groove 21. When the threaded rod 63 rotates, the grooves 67 on the threaded rod 63 rotate, causing the positions of the grooves 67 and the top rod 66 to change. In the present invention, the grooves 67 are all arc-shaped. When the threaded rod 63 rotates, the grooves 67 can gradually push the top rod 66 to move in a direction away from the threaded rod 63, so that the top rod 66 extends into the assembly groove 21. At this time, the assembly ring 22 is placed in the assembly groove 21. The assembly ring 22 slides under the action of gravity and is finally intercepted by the top rod 66. At this time, when the magnetic rod 7 is adjusted, it is not necessary for the staff to manually maintain the position of the assembly ring 22, further enhancing the convenience of equipment use.

[0075] As Figure 10 shown, a magnetotelluric prospecting method for the earth includes the following steps:

[0076] S1: With the assistance of tools, the staff digs a groove on the pre-demarcated ground. The depth of the groove is greater than 30 CM. Then, the installation frame 1 is lowered into the groove, and the pressure plate 4 and the baffle 41 are installed in the assembly groove 21 synchronously;

[0077] S2: With the assistance of tools, backfill the excavated soil to the outside of the installation frame 1, and during the backfilling process, compact the soil until the soil is flush with the ground, and then remove the pressing plate 4 and the baffle 41;

[0078] S3: Backfill a part of the soil into the assembly groove 21, use the pressing plate 4 and the baffle 41 to tamp the soil in the assembly groove 21, and then rotate the threaded rod 63 with the aid of tools, causing the ejector rod 66 to extend into the assembly groove 21;

[0079] S4: Install the assembly ring 22 at the top of the assembly groove 21. The assembly ring 22 and the magnetic rod 7 descend under the action of gravity until blocked by the ejector rod 66. At this time, manually turn the adjusting bolt 34, and with the assistance of the bubble level on the magnetic rod 7, make the magnetic rod 7 horizontal;

[0080] S5: Take out the adjusted assembly ring 22 and magnetic rod 7. After filtering the soil, first backfill a layer of soil into the assembly groove 21, then install the assembly ring 22 and the magnetic rod 7, and finally fill another layer of small-particle soil to form the shaping layer 23;

[0081] S6: Place the soil-filled load-bearing membrane bag 5 in the cylindrical structure formed by the baffle 41 and the pressing plate 4, and use tools to tamp the soil in the load-bearing membrane bag 5, and remove the baffle 41 and the pressing plate 4, then the splicing block 24 is made;

[0082] S7: First place the load-bearing membrane bag 5 and the splicing block 24 in the assembly groove 21, then place the unfolded baffle 41 and pressing plate 4 on the installation frame 1, and then connect the connecting wire of the magnetic rod 7 to the test instrument.

[0083] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A geoelectric and geomagnetic field geophysical prospecting device, comprising an installation frame (1) and a magnetic rod (7), both the installation frame (1) and the magnetic rod (7) are buried underground, and the magnetic rod (7) is installed on the installation frame (1); It is characterized in that: It further includes a splicing structure, which cooperates with the installation frame (1) and is used to reduce the probability of the magnetic rod (7) tilting after being buried; The splicing structure includes a buried groove (2), an assembly ring (22), a shaping layer (23) and a splicing block (24); The buried groove (2) is opened on the ground, and the installation frame (1) is fixedly installed in the buried groove (2); The inner cavity of the installation frame (1) forms an assembly groove (21), the assembly groove (21) is open at the top of the installation frame (1), the assembly ring (22) is slidably installed in the assembly groove (21), and the magnetic rod (7) is installed on the assembly ring (22) through a fine-tuning mechanism; The shaping layer (23) is composed of small particle loose soil, the shaping layer (23) is located at the bottom of the assembly groove (21), and the shaping layer (23) wraps the assembly ring (22) and the magnetic rod (7); The splicing block (24) is a high-density plate-like structure formed by pressing soil, the splicing block (24) is installed above the shaping layer (23), and the splicing block (24) and the plastic layer are used to fill the assembly groove (21).

2. The magnetotelluric geophysical prospecting device according to claim 1, wherein: The fine-tuning mechanism is used to adjust the relative angle between the magnetic rod (7) and the assembly ring (22), and the fine-tuning mechanism includes an installation ring (3), an adjustment rod (31) and a support spring (36); Symmetrically arranged installation rings (3) are fixedly installed on the assembly ring (22), an adjustment rod (31) is rotatably installed on the installation rings (3) together, an installation groove (32) is opened in the middle of the adjustment rod (31), and the magnetic rod (7) is detachably and fixedly installed in the installation groove (32); Adjustment grooves (33) are opened on the installation ring (3), the adjustment grooves (33) are all arc-shaped, an adjustment bolt (34) is threadedly installed on the installation ring (3), the adjustment bolt (34) extends into the adjustment groove (33), and a top piece (35) is fixedly installed on the adjustment rod (31), and the top piece (35) is located on the movement path of the adjustment bolt (34); A support spring (36) is fixedly installed at the bottom of the adjustment groove (33), and the support spring (36) abuts against the bottom of the top piece (35).

3. The magnetotelluric geophysical prospecting device according to claim 2, wherein: The buried groove (2) and the installation frame (1) are of matching dimensions, the installation frame (1) is inlaid and installed in the buried groove (2), and the soil outside the buried groove (2) is compacted.

4. The geoelectric magnetic field geophysical prospecting device according to claim 3, characterized in that: It further includes a shaping mechanism, which cooperates with the installation frame (1) and is used to shape the shape of the buried groove (2), and the shaping mechanism includes a pressing plate (4) and a baffle (41); The pressing plate (4) has the same shape as the bottom surface of the assembly groove (21), the baffle (41) is designed in plural, and a plurality of the baffles (41) correspond to the inner wall of the assembly groove (21) one by one. The baffle (41) is installed on the pressing plate (4), and in the initial state, the baffle (41) and the pressing plate (4) cooperate to separate the assembly groove (21) from the buried groove (2).

5. A magnetotelluric geophysical prospecting device according to claim 4, characterized in that: The baffle plate (41) is hinged to the pressing plate (4). The adjacent two baffle plates (41) are both provided with inclined surfaces on the mutually approaching sides. The baffle plate (41) and the pressing plate (4) cooperate to form a tubular structure with an open top. The top of the mounting frame (1) is fixedly provided with evenly distributed limit blocks (42). When the baffle plate (41) and the pressing plate (4) are in the same horizontal plane, the limit blocks (42) are located between the adjacent two baffle plates (41).

6. The magnetotelluric geophysical prospecting device according to claim 5, characterized in that: The shaping mechanism further includes a bearing film bag (5). The bearing film bag (5) is a film-like structure made of plastic film. The tubular structure formed by the baffle plate (41) and the pressing plate (4) is matched with the bearing film bag (5). The bearing film bag (5) cooperates with the baffle plate (41) and the pressing plate (4) to manufacture the splicing block (24).

7. An earth electromagnetic field geophysical prospecting device according to claim 6, characterized in that: A plurality of penetration holes (51) are formed in the bearing film bag (5). The bearing film bag (5) cooperates with the penetration holes (51) to irrigate brine into the buried groove (2).

8. The magnetotelluric geophysical prospecting device according to claim 7, characterized in that: A plurality of extension grooves (6) are formed in the mounting frame (1). The extension grooves (6) are all parallel to the bottom surface of the assembly groove (21). Extension insertion rods (61) are hermetically installed in the extension grooves (6). A pressurization groove (62) is formed at the top of the mounting frame (1). A threaded rod (63) is rotatably installed in the pressurization groove (62). A sealing plate (64) is slidably installed in the pressurization groove (62). The sealing plate (64) is in screw drive connection with the threaded rod (63). The pressurization groove (62) is conductively connected to the extension groove (6) through a pipeline. Hydraulic oil is filled in both the pressurization groove (62) and the extension groove (6).

9. The magnetotelluric geophysical prospecting device according to claim 8, characterized in that: A telescopic groove (65) is formed in the mounting frame (1). The telescopic groove (65) is conductively connected to both the pressurization groove (62) and the assembly groove (21). A top rod (66) is elastically installed in the telescopic groove (65) through a spring. Both the telescopic groove (65) and the top rod (66) are designed in a T shape. The top rod (66) is aligned with the top end of the threaded rod (63). Uniformly distributed grooves (67) are formed at the top end of the threaded rod (63). In the initial state, the top rod (66) extends into the grooves (67). When the threaded rod (63) rotates, the top rod (66) is pushed to extend into the assembly groove (21).

10. A geoelectric magnetic field geophysical prospecting method, characterized in that: This method uses the magnetotelluric prospecting device described in claim 9. This method includes the following steps: S1: Dig a groove on the pre-demarcated ground, lower the mounting frame (1) into the groove, and synchronously install the pressing plate (4) and the baffle plate (41) in the assembly groove (21). S2: Backfill the soil outside the mounting frame (1) and synchronously perform a compaction treatment until the soil is flush with the ground, and then take out the pressing plate (4) and the baffle plate (41). S3: Backfill part of the soil into the assembly groove (21), tamp the soil, and then rotate the threaded rod (63) so that the top rod (66) extends into the assembly groove (21). S4: Install the assembly ring (22) in the assembly groove (21) and be blocked by the top rod (66). Turn the adjusting bolt (34), and with the assistance of the bubble level on the magnetic rod (7), make the magnetic rod (7) horizontal. S5: Take out the assembly ring (22) and the magnetic rod (7), filter the soil and backfill it into the assembly groove (21), and install the assembly ring (22) and the magnetic rod (7) in the middle of the backfilled soil to form the shaping layer (23); S6: Place the soil-filled carrier membrane bag (5) in the cylindrical structure formed by the baffle (41) and the pressing plate (4). After tamping, the splicing block (24) is made; S7: Place the carrier membrane bag (5) and the splicing block (24) in the assembly groove (21), then place the unfolded baffle (41) and pressing plate (4) on the installation frame (1), and then connect the magnetic rod (7) connecting wire to the test instrument.

Images