Ground shielding effectiveness system for super-large area super-high pressure metering mutual inductance laboratory

Abstract

The application discloses a kind of super-large area super-high pressure measurement mutual inductance laboratory ground shielding efficiency systems, including shielding ground structure, shielding wall, wall ground connection node, threshold, threshold connection node, pipeline and pipeline connection node;Shielding ground structure is constructed on laboratory ground, shielding wall is constructed on laboratory wall, shielding wall is connected with shielding ground structure by wall ground connection node;Threshold is constructed in shielding ground structure and is connected with shielding ground structure by threshold connection node, the top surface of threshold is flush with the top surface of shielding ground structure;Pipeline is worn in shielding ground structure, pipeline is connected with shielding ground structure by pipeline connection node;Shielding ground structure, shielding wall, threshold and pipeline form integrated shielding structure.The application relates to the technical field of laboratory construction, can solve the problem that ground shielding effect and bearing capacity in prior art cannot meet the requirements of super-large area super-high pressure measurement mutual inductance laboratory on shielding effect and bearing capacity.

Description

Technical Field

[0001] This invention relates to the field of laboratory construction technology, and in particular to a ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories. Background Technology

[0002] As society's demand for electricity increases, people's research on high-voltage and ultra-high-voltage electricity has gradually deepened. The requirements for the testing environment of instruments and equipment used for high-voltage power testing are also getting higher and higher, requiring laboratories to have a certain degree of electromagnetic shielding capabilities.

[0003] Currently, existing electromagnetic shielding room floors generally use perforated aluminum-zinc corrugated steel plates as the shielding layer, and the floor area inside the shielding room is relatively small with weak load-bearing capacity; existing ground shielding panels generally use a single layer of perforated aluminum-zinc corrugated steel plates as the ground shielding system.

[0004] For ultra-large area ultra-high voltage metrology and transformer laboratories, higher shielding effectiveness is required, and the ground must also support various large experimental equipment, making the ground's load-bearing capacity crucial. Existing electromagnetic shielding ground technologies and their load-bearing capacities are insufficient to meet the shielding and load-bearing requirements of ultra-large area ultra-high voltage metrology and transformer laboratories. Furthermore, the ground of such laboratories requires the installation of various pipelines, and electromagnetic pollution can easily occur at pipeline junctions. Therefore, there is a need to provide a ground shielding effectiveness system for ultra-large area ultra-high voltage metrology and transformer laboratories that can address the shortcomings of existing technologies in meeting these requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories, which can solve the problem that the ground shielding effect and load-bearing capacity of existing technologies cannot meet the requirements of ultra-large area ultra-high voltage metering and mutual inductance laboratories for shielding effect and load-bearing capacity.

[0006] This invention is implemented as follows:

[0007] A ground shielding effectiveness system for an ultra-large area ultra-high voltage metering and mutual inductance laboratory includes a shielded ground structure, shielded walls, wall-to-ground connection nodes, a threshold, a threshold connection node, pipes, and pipe connection nodes. The shielded ground structure is constructed on the laboratory floor, and the shielded walls are constructed on the laboratory walls, with the shielded walls connected to the shielded ground structure via the wall-to-ground connection nodes. The threshold is constructed within the shielded ground structure and connected to it via the threshold connection nodes, with the top surface of the threshold flush with the top surface of the shielded ground structure. Pipes are installed within the shielded ground structure and connected to it via pipe connection nodes. The shielded ground structure, shielded walls, threshold, and pipes form an integrated shielding structure.

[0008] The shielded ground structure includes high-pressure jet grouting piles, a plain soil layer, a cushion layer, a concrete cushion layer, a waterproof layer, a leveling layer, a shielding layer, a load-bearing layer, a floor layer, and a double-layer steel mesh. The plain soil layer, cushion layer, concrete cushion layer, waterproof layer, leveling layer, shielding layer, load-bearing layer, and floor layer are constructed sequentially from bottom to top on the laboratory floor. Several high-pressure jet grouting piles are constructed within the plain soil layer to form a composite foundation. The double-layer steel mesh is constructed within the load-bearing layer. The wall-to-ground connection nodes, threshold connection nodes, and pipe connection nodes are all connected to the shielding layer.

[0009] The high-pressure jet grouting piles have a diameter of 600mm, and several high-pressure jet grouting piles are arranged in a matrix. The vertical compressive bearing capacity of a single high-pressure jet grouting pile is not less than 110kN.

[0010] The top surface of the subgrade soil layer is higher than the top of the high-pressure jet grouting pile, the compaction coefficient of the subgrade soil layer is greater than 0.95, the bearing capacity characteristic value of the subgrade soil layer is greater than 100kN, and the bearing capacity characteristic value of the composite foundation is not less than 100kPa.

[0011] The mattress layer is laid on the subgrade soil layer with a laying height of 300mm. The mattress layer is formed by compacting graded crushed stone with a compaction coefficient greater than 0.95 and a bearing capacity characteristic value greater than 100kN.

[0012] The concrete cushion layer is constructed on the mattress layer, with a construction height of 100-105mm, and the overall flatness of the concrete cushion layer does not exceed ±5mm.

[0013] The waterproof layer is made of modified bitumen waterproof membrane, which is laid on the concrete subbase along with the ground.

[0014] The leveling layer is made of 1:3 cement mortar with a thickness of 20mm and an overall flatness error of no more than 5mm.

[0015] The load-bearing layer is a 250mm thick concrete layer, and the height of the load-bearing layer is greater than the height of the double-layer steel mesh, so that the load-bearing layer completely covers the double-layer steel mesh.

[0016] The double-layer steel mesh is formed by overlapping and spot welding upper and lower double-layer steel meshes to form a whole, and the double-layer steel mesh is spot welded to the shielding layer to form a whole;

[0017] The floor layer is made of 5mm thick corundum wear-resistant flooring material, and the overall flatness of the floor layer does not exceed ±3mm.

[0018] The shielding layer is composed of several shielding steel plates that are stacked in sequence. One end of each shielding steel plate forms a first rib with an inverted L-shaped structure, and the other end of the shielding steel plate forms a second rib with an inverted L-shaped structure. The second rib is matched and overlapped on the first rib to form a shielding plate rib, and the two adjacent shielding steel plates are spliced ​​into an integral structure. A double-layer steel mesh is overlapped on the shielding plate rib and spot-welded together.

[0019] The shielding steel plate can be made of galvanized steel plate with a thickness of 0.15mm, and the flatness error of several shielding steel plates spliced ​​together is no more than 3mm.

[0020] The wall-to-ground connection node includes a shielding extension, a connector, and a shielding keel. The shielding keel is circumferentially arranged along the connection between the shielded ground structure and the shielded wall, and the shielded wall is constructed on top of the shielding keel. One end of the shielding extension overlaps with the edge of the shielding layer, and the other end of the shielding extension overlaps with one end of the connector. The other end of the connector overlaps with the shielding keel, so that the shielding wall is connected to the shielding layer as a whole through the wall-to-ground connection node.

[0021] The shielding wall includes an inner shielding mesh and an outer shielding plate. The inner shielding mesh is located inside the outer shielding plate, and the inner shielding mesh and the outer shielding plate are connected by connecting components to form a double-layer shielding wall.

[0022] The threshold connection node includes pads and lap joints; several pads are spaced apart at the bottom of the threshold, so that the threshold is embedded in the load-bearing layer through the pads, and the top surface of the threshold is flush with the top surface of the floor layer; the lap joint overlaps between the bottom of the threshold and the shielding layer, and the lower steel bar of the double-layer steel mesh overlaps at the bottom of the threshold.

[0023] The pipe connection node includes a sleeve and a gasket; the inner diameter of the sleeve is larger than the outer diameter of the pipe, so that the sleeve fits onto the pipe; the sleeve is located inside the load-bearing layer, and the bottom of the sleeve is fixedly connected to the shielding layer; the gasket has a ring structure, the inner ring of the gasket is connected to the bottom outer wall of the sleeve, and the outer ring of the gasket is connected to the edge of the opening in the shielding layer.

[0024] The inner diameter of the sleeve is 5-8 cm larger than the outer diameter of the pipe, and the height of the sleeve is 200 mm.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The shielded ground structure of this invention strengthens the bearing capacity of the composite foundation through a subgrade layer with high-pressure jet grouting piles and a cushion layer, laying the foundation for the bearing capacity of the subsequent shielded ground structure. By introducing a leveling layer, the construction flatness of the shielding layer is improved, and the material of the shielding layer is selected as 1.5mm thick galvanized steel plate, which enhances the shielding effectiveness of the shielding layer and facilitates subsequent cross-processing with other nodes. At the same time, setting the load-bearing layer on top of the shielding layer can compact the gaps below the shielding layer to a certain extent, and the diamond abrasion wear-resistant floor layer on top can also improve the wear resistance of the ground, increasing the comprehensive performance of the shielded ground structure and meeting the requirements of ultra-large area ultra-high voltage metering and mutual inductance laboratories for shielding effect and bearing capacity.

[0027] 2. The shielding layer of the present invention uses a shielding steel plate with shielding ribs, which allows the double-layer steel mesh to be placed on the shielding ribs, so that the shielding layer is connected to the double-layer steel mesh, thereby enhancing the shielding effect of the shielding ground structure and saving construction time and costs associated with placing pads under the double-layer steel mesh during construction.

[0028] 3. The present invention connects the shielding wall to the shielding ground structure through the bottom shielding keel. The shielding keel also serves to install and fix the double-layer shielding wall, which facilitates the interconnection and overall connection of the entire laboratory shielding system.

[0029] 4. In this invention, the lower layer of the double-layer steel mesh is welded and fixed above the bottom of the threshold. This not only fixes the threshold and prevents it from shifting during concrete pouring, thus preventing damage to the weld between the threshold and the shielding layer, but also connects the threshold to the laboratory shielding system through the lap joint, thereby enhancing the overall shielding capability of the laboratory.

[0030] 5. The present invention adds a sleeve around the pipe, which can not only allow concrete to flow into the area around the pipe, but also enhance the shielding effectiveness at the node after the pipe passes through the shielding layer. The setting of the gasket can also provide double protection at the node and the connection of the shielding layer. Attached Figure Description

[0031] Figure 1 This is a cross-sectional view of the ground shielding effectiveness system for the ultra-large area ultra-high voltage metering and mutual inductance laboratory of the present invention.

[0032] Figure 2 This is a schematic diagram of the overlapping of the shielding layer in the ultra-large area ultra-high voltage metering and mutual inductance laboratory ground shielding effectiveness system of the present invention;

[0033] Figure 3 This is a cross-sectional view of the wall-to-ground connection node in the ultra-large area ultra-high voltage metering and mutual inductance laboratory ground shielding effectiveness system of the present invention.

[0034] Figure 4This is a cross-sectional view of the threshold connection node in the ultra-large area ultra-high voltage metering and mutual inductance laboratory ground shielding effectiveness system of the present invention.

[0035] Figure 5 This is a cross-sectional view of the pipe connection node in the ultra-large area ultra-high voltage metering and mutual inductance laboratory ground shielding effectiveness system of the present invention.

[0036] In the diagram, the components are: 1. High-pressure jet grouting pile; 2. Plain soil layer; 3. Subgrade layer; 4. Concrete cushion layer; 5. Waterproof layer; 6. Leveling layer; 7. Shielding layer; 701. Shielding steel plate; 702. First rib; 703. Second rib; 8. Load-bearing layer; 9. Ground layer; 10. Double-layer steel mesh; 11. Shielding plate rib; 12. Shielding wall; 121. Inner shielding mesh; 122. Outer shielding plate; 13. Threshold; 14. Pipe; 15. Shielding extension; 16. Connector; 17. Shielding keel; 18. Spacer block; 19. Overlap joint; 20. Sleeve; 21. Washer ring. Detailed Implementation

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

[0038] Please see the appendix Figure 1 A ground shielding effectiveness system for an ultra-large area ultra-high voltage metering and mutual inductance laboratory includes a shielded ground structure, a shielded wall 12, a wall-to-ground connection node, a threshold 13, a threshold connection node, a pipe 14, and a pipe connection node. The shielded ground structure is constructed on the laboratory floor, the shielded wall 12 is constructed on the laboratory wall, and the shielded wall 12 is connected to the shielded ground structure through the wall-to-ground connection node. The threshold 13 is constructed within the shielded ground structure and is connected to the shielded ground structure through the threshold connection node, and the top surface of the threshold 13 is flush with the top surface of the shielded ground structure. The pipe 14 is installed within the shielded ground structure and is connected to the shielded ground structure through the pipe connection node. The shielded ground structure, shielded wall 12, threshold 13, and pipe 14 form an integral shielding structure.

[0039] The shielded floor structure is connected to the shielded wall 12 through the wall-to-floor connection node, the shielded floor structure is connected to the threshold 13 through the threshold connection node, and the shielded floor structure is connected to the pipe 14 through the pipe connection node, so that the door, floor and wall are connected to form a whole, forming an overall shielding effect, and the pipe 14 has a good shielding effect at the passage part, avoiding electromagnetic pollution.

[0040] Please see the appendix Figure 1The shielded ground structure includes high-pressure jet grouting piles 1, a plain soil layer 2, a cushion layer 3, a concrete cushion layer 4, a waterproof layer 5, a leveling layer 6, a shielding layer 7, a load-bearing layer 8, a floor layer 9, and a double-layer steel mesh 10. The plain soil layer 2, cushion layer 3, concrete cushion layer 4, waterproof layer 5, leveling layer 6, shielding layer 7, load-bearing layer 8, and floor layer 9 are constructed sequentially from bottom to top on the laboratory floor. Several high-pressure jet grouting piles 1 are constructed within the plain soil layer 2 to form a composite foundation. The double-layer steel mesh 10 is constructed within the load-bearing layer 8. The wall-to-ground connection nodes, threshold connection nodes, and pipe connection nodes are all connected to the shielding layer 7.

[0041] The construction of high-pressure jet grouting piles 1, plain soil layer 2 and mattress layer 3 improves the load-bearing capacity of the shielded ground structure. The construction of concrete mattress layer 4 and waterproof layer 5 improves the waterproof and moisture-proof performance of the shielded ground structure. The leveling layer 6 facilitates the construction of shielding layer 7. The load-bearing layer 8 is set on top of shielding layer 7, and a floor layer 9 is set on top to improve the wear resistance of the ground.

[0042] Preferably, the high-pressure jet grouting pile 1 has a diameter of 600mm, and several high-pressure jet grouting piles 1 are arranged in a matrix. The vertical compressive bearing capacity of a single high-pressure jet grouting pile 1 is not less than 110kN, thereby improving the bearing capacity of the shielded ground structure.

[0043] After the high-pressure jet grouting pile 1 is constructed, plain soil needs to be backfilled and compacted on the top of the pile 1 to form plain soil layer 2. Preferably, the top surface of the plain soil layer 2 is higher than the top of the high-pressure jet grouting pile 1, the compaction coefficient of the plain soil layer 2 is greater than 0.95, the characteristic value of the bearing capacity of the plain soil layer 2 is greater than 100kN, and the characteristic value of the bearing capacity of the composite foundation is not less than 100kPa, thereby improving the bearing capacity of the shielded ground structure.

[0044] Preferably, the mattress layer 3 is laid on the subgrade layer 2 with a laying height of 300mm. The mattress layer 3 is formed by compacting graded crushed stone with a compaction coefficient greater than 0.95. The characteristic value of the bearing capacity of the mattress layer 3 is greater than 100kN, thereby improving the bearing capacity of the shielded ground structure.

[0045] Preferably, the concrete cushion layer 4 is constructed on the mattress layer 3, with a construction height of 100-105mm and an optimal thickness of 100mm. The overall flatness of the concrete cushion layer 4 does not exceed ±5mm, thereby improving the waterproof and moisture-proof performance of the shielded ground structure.

[0046] Preferably, the waterproof layer 5 is made of modified bitumen waterproof membrane, which is fully laid on the concrete subbase 4 along with the ground to improve the waterproof and moisture-proof performance of the shielded ground structure.

[0047] Preferably, the leveling layer 6 is made of 1:3 cement mortar with a thickness of 20mm and an overall flatness error of no more than 5mm.

[0048] Please see the appendix Figure 2 Preferably, the shielding layer 7 is composed of several shielding steel plates 701 stacked sequentially. One end of each shielding steel plate 701 forms a first rib 702 with an inverted L-shaped structure, and the other end of the shielding steel plate 701 forms a second rib 703 with an inverted L-shaped structure. The second rib 703 is matched and overlapped on the first rib 702 to form a shielding plate rib 11, and adjacent shielding steel plates 701 are spliced ​​into an integral structure. The double-layer steel mesh 10 is overlapped on the shielding plate rib 11 and spot-welded.

[0049] The quantity and size of the shielding steel plates 701 can be adjusted according to the actual ground area. The overlapping of the second rib 703 with the first rib 702 in an inverted L-shaped structure ensures a seamless and reliable connection between adjacent shielding steel plates 701, thus ensuring shielding effectiveness.

[0050] The shielding rib 11 formed by the overlap of the second rib 703 and the first rib 702 facilitates the overlap of adjacent shielding steel plates 701 to form a shielding layer 7 with good integrity, and also facilitates the overlap of the double-layer steel mesh 10.

[0051] Preferably, the shielding steel plate 701 can be made of galvanized steel plate with a thickness of 0.15mm, and the flatness error of several shielding steel plates 701 spliced ​​together is no more than 3mm, so as to ensure the shielding effectiveness of the shielding ground structure.

[0052] Preferably, the load-bearing layer 8 is a 250mm thick concrete layer, and the height of the load-bearing layer 8 is greater than the height of the double-layer steel mesh 10, so that the load-bearing layer 8 completely encloses the double-layer steel mesh 10.

[0053] Preferably, the double-layer steel mesh 10 is formed by overlapping and spot welding upper and lower double-layer steel meshes to form a whole, and the double-layer steel mesh 10 and the shielding layer 7 are spot welded to form a whole, thereby improving the load-bearing capacity of the shielding ground structure.

[0054] Preferably, the floor layer 9 is made of a 5mm thick corundum wear-resistant flooring material, and the overall flatness of the floor layer 9 does not exceed ±3mm, thereby improving the wear resistance of the shielded ground structure.

[0055] Please see the appendix Figure 3Preferably, the wall-to-ground connection node includes a shielding extension 15, a connector 16, and a shielding keel 17; the shielding keel 17 is circumferentially arranged along the connection part between the shielding ground structure and the shielding wall 12, and the shielding wall 12 is constructed on top of the shielding keel 17; one end of the shielding extension 15 overlaps with the edge of the shielding layer 7, the other end of the shielding extension 15 overlaps with one end of the connector 16, and the other end of the connector 16 overlaps with the shielding keel 17, so that the shielding wall 12 is connected to the shielding layer 7 as a whole through the wall-to-ground connection node, thereby achieving the purpose of connecting the shielding wall 12 with the shielding ground structure.

[0056] The shielding keel 17 facilitates the installation and fixing of the shielding wall 12, and also connects the shielding wall 12 with the shielding ground structure to form an integrated wall and ground shielding system.

[0057] The shielding wall 12 includes an inner shielding mesh 121 and an outer shielding plate 122. The inner shielding mesh 121 is disposed on the inner side of the outer shielding plate 122. The inner shielding mesh 121 and the outer shielding plate 122 are connected by connecting members to form a double-layer shielding wall 12.

[0058] Preferably, the connection nodes between the inner shielding mesh 121, the outer shielding plate 122, the shielding extension 15, the connector 16, and the shielding keel 17 are all fully welded; the shielding extension 15 can be made of 1.5mm thick galvanized steel plate, the connector 16 can be made of 3mm thick steel plate, the shielding keel 17 can be made of 80mm×80mm×3mm galvanized square tube, the outer shielding plate 122 can be made of 1.5mm thick galvanized steel plate, and the inner shielding mesh 121 can be made of 0.6mm thick perforated aluminum-zinc corrugated steel plate (porosity 2%, hole diameter 0.78mm).

[0059] Please see the appendix Figure 4 The threshold connection node includes pads 18 and lap joints 19; several pads 18 are respectively spaced at the bottom of the threshold 13, so that the threshold 13 is embedded in the load-bearing layer 8 through the pads 18, and the top surface of the threshold 13 is flush with the top surface of the floor layer 9; the lap joint 19 overlaps between the bottom of the threshold 13 and the shielding layer 7, and the lower steel bar of the double-layer steel mesh 10 overlaps at the bottom of the threshold 13.

[0060] The lap joint 19 connects the threshold 13 to the shielded ground structure, facilitating both door installation and connection to the entire wall and floor shielding system. The pad 18 ensures the top surface of the threshold 13 is flush with the top surface of the floor layer 9, guaranteeing the load-bearing capacity of the threshold 13 and maintaining a level surface.

[0061] Preferably, the threshold 13 can be made of H-beam steel with a specification of 200mm×200mm×10mm and material of Q235B; the pad 18 can be made of galvanized square tubing of 50mm×50mm×3mm; and the lap joint 19 can be made of 1.5mm thick galvanized steel plate. The lap joints of the lap joint 19, threshold 13, shielding layer 7, and double-layer steel mesh 10 are all fully welded, connecting the door frame into the shielding system and improving the overall shielding effect of the laboratory.

[0062] Please see the appendix Figure 5 The pipe connection node includes a sleeve 20 and a gasket 21; the inner diameter of the sleeve 20 is larger than the outer diameter of the pipe 14, so that the sleeve 20 is fitted onto the pipe 14; the sleeve 20 is located inside the load-bearing layer 8, and the bottom of the sleeve 20 is fixedly connected to the shielding layer 7; the gasket 21 has a ring structure, the inner ring of the gasket 21 is connected to the bottom outer wall of the sleeve 20, and the outer ring of the gasket 21 is connected to the edge of the opening in the shielding layer 7, thereby achieving the purpose of enhancing the shielding effectiveness at the pipe node.

[0063] The periphery of the pipe 14 is connected to the shielding layer 7 through the sleeve 20 and the gasket 21, which ensures the shielding effectiveness of the pipe 14 and avoids electromagnetic interference.

[0064] Preferably, the inner diameter of the sleeve 20 is 5-8 cm larger than the outer diameter of the pipe 14, with 6 cm being optimal, and the height of the sleeve 20 is 200 mm.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A ground-based shielding effectiveness system for an ultra-large area ultra-high voltage metering and mutual inductance laboratory, characterized in that: The shielding structure includes a shielded ground structure, a shielded wall (12), a wall-to-ground connection node, a threshold (13), a threshold connection node, a pipe (14), and a pipe connection node. The shielded ground structure is constructed on the laboratory floor, the shielded wall (12) is constructed on the laboratory wall, and the shielded wall (12) is connected to the shielded ground structure through the wall-to-ground connection node. The threshold (13) is constructed inside the shielded ground structure and is connected to the shielded ground structure through the threshold connection node, and the top surface of the threshold (13) is flush with the top surface of the shielded ground structure. The pipe (14) is installed inside the shielded ground structure and is connected to the shielded ground structure through the pipe connection node. The shielded ground structure, the shielded wall (12), the threshold (13), and the pipe (14) form an integrated shielding structure. The shielded ground structure includes high-pressure jet grouting piles (1), a plain soil layer (2), a cushion layer (3), a concrete cushion layer (4), a waterproof layer (5), a leveling layer (6), a shielding layer (7), a load-bearing layer (8), a floor layer (9), and a double-layer steel mesh (10). The plain soil layer (2), cushion layer (3), concrete cushion layer (4), waterproof layer (5), leveling layer (6), shielding layer (7), load-bearing layer (8), and floor layer (9) are constructed sequentially from bottom to top on the laboratory ground. Several high-pressure jet grouting piles (1) are constructed within the plain soil layer (2) to form a composite foundation. The double-layer steel mesh (10) is constructed within the load-bearing layer (8). The wall-to-ground connection nodes, threshold connection nodes, and pipe connection nodes are all connected to the shielding layer (7). The shielding layer (7) is composed of several shielding steel plates (701) stacked in sequence. One end of each shielding steel plate (701) forms a first rib (702) with an inverted L-shaped structure, and the other end of the shielding steel plate (701) forms a second rib (703) with an inverted L-shaped structure. The second rib (703) is matched and overlapped on the first rib (702) to form a shielding plate rib (11), and two adjacent shielding steel plates (701) are spliced ​​into an integral structure. The double-layer steel mesh (10) is overlapped on the shielding plate rib (11) and spot welded together. The threshold connection node includes pads (18) and lap joints (19); several pads (18) are respectively spaced at the bottom of the threshold (13), so that the threshold (13) is embedded in the load-bearing layer (8) through the pads (18), and the top surface of the threshold (13) is flush with the top surface of the floor layer (9); the lap joints (19) overlap between the bottom of the threshold (13) and the shielding layer (7), and the lower steel bar of the double-layer steel mesh (10) overlaps at the bottom of the threshold (13).

2. The ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories according to claim 1, characterized in that: The diameter of the high-pressure jet grouting pile (1) is 600mm. Several high-pressure jet grouting piles (1) are arranged in a matrix. The characteristic value of the vertical compressive bearing capacity of a single high-pressure jet grouting pile (1) is not less than 110kN. The top surface of the subgrade (2) is higher than the top of the high-pressure jet grouting pile (1), the compaction coefficient of the subgrade (2) is greater than 0.95, the bearing capacity characteristic value of the subgrade (2) is greater than 100kN, and the bearing capacity characteristic value of the composite foundation is not less than 100kPa. The mattress layer (3) is laid on the plain soil layer (2) with a laying height of 300mm. The mattress layer (3) is formed by compacting graded crushed stone with a compaction coefficient greater than 0.

95. The characteristic value of the bearing capacity of the mattress layer (3) is greater than 100kN. The concrete cushion layer (4) is constructed on the mattress layer (3) with a construction height of 100-105mm. The overall flatness of the concrete cushion layer (4) shall not exceed ±5mm. The waterproof layer (5) is made of modified bitumen waterproof membrane, which is laid on the concrete cushion layer (4) along with the ground. The leveling layer (6) is made of 1:3 cement mortar with a thickness of 20mm and an overall flatness error of no more than 5mm. The load-bearing layer (8) is a 250mm thick concrete layer. The height of the load-bearing layer (8) is greater than the height of the double-layer steel mesh (10), so that the load-bearing layer (8) completely covers the double-layer steel mesh (10). The double-layer steel mesh (10) is formed by overlapping and spot welding of upper and lower double-layer steel meshes to form a whole, and the double-layer steel mesh (10) and the shielding layer (7) are spot welded to form a whole; The floor layer (9) is made of 5mm thick corundum wear-resistant flooring material, and the overall flatness of the floor layer (9) does not exceed ±3mm.

3. The ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories according to claim 1, characterized in that: The shielding steel plate (701) can be made of galvanized steel plate with a thickness of 0.15mm, and the flatness error of several shielding steel plates (701) spliced ​​together is no more than 3mm.

4. The ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories according to claim 1, characterized in that: The wall-to-ground connection node includes a shielding extension (15), a connector (16), and a shielding keel (17). The shielding keel (17) is circumferentially arranged along the connection between the shielding ground structure and the shielding wall (12), and the shielding wall (12) is constructed on the top of the shielding keel (17). One end of the shielding extension (15) overlaps with the edge of the shielding layer (7), and the other end of the shielding extension (15) overlaps with one end of the connector (16). The other end of the connector (16) overlaps on the shielding keel (17), so that the shielding wall (12) is connected to the shielding layer (7) as a whole through the wall-to-ground connection node.

5. The ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories according to claim 1, characterized in that: The shielding wall (12) includes an inner shielding mesh (121) and an outer shielding plate (122). The inner shielding mesh (121) is located inside the outer shielding plate (122). The inner shielding mesh (121) and the outer shielding plate (122) are connected by connecting members to form a double-layer shielding wall (12).

6. The ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories according to claim 1, characterized in that: The pipe connection node includes a sleeve (20) and a gasket (21); the inner diameter of the sleeve (20) is larger than the outer diameter of the pipe (14), so that the sleeve (20) is fitted onto the pipe (14); the sleeve (20) is located inside the load-bearing layer (8), and the bottom of the sleeve (20) is fixedly connected to the shielding layer (7); the gasket (21) has a ring structure, the inner ring of the gasket (21) is connected to the bottom outer wall of the sleeve (20), and the outer ring of the gasket (21) is connected to the edge of the opening of the shielding layer (7).

7. The ground shielding effectiveness system for ultra-large area ultra-high voltage metering and mutual inductance laboratories according to claim 6, characterized in that: The inner diameter of the sleeve (20) is 5-8 cm larger than the outer diameter of the pipe (14), and the height of the sleeve (20) is 200 mm.

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