Grating steel pipe constraint block stone concrete bullet shielding structure and preparation method thereof

Abstract

The invention provides a grid steel pipe restrained block stone concrete bullet shielding structure and a preparation method thereof. The structure comprises a grid steel pipe structure and block stone concrete filled in the grid steel pipe structure; the grating steel pipe structure comprises a plurality of longitudinal steel plates, a plurality of transverse steel plates and an outer frame; a plurality of rectangular slots are equally processed in each longitudinal steel plate in the length direction of the longitudinal steel plate, and a plurality of rectangular slots are correspondingly equally processed in each transverse steel plate in the length direction of the transverse steel plate; the length of the rectangular slot is half of the width of the steel plate; the plurality of longitudinal steel plates and the plurality of transverse steel plates are vertically and horizontally inserted through the rectangular slots to form a plurality of square grid units which are identical in shape and size, and the joints of the slots are fixed through welding; the outer frame and the grid structure formed by inserting are welded into a whole to jointly form a closed grid steel pipe structure; the block stone concrete comprises block stone aggregate and a cement-based material.

Description

Technical Field

[0001] This invention relates to the field of building protective structure technology, and in particular, to a grid steel pipe constrained boulders concrete shielding structure and its preparation method. Background Technology

[0002] Traditional plain concrete or reinforced concrete protective structures are prone to typical damage such as collapse, pitting, brittle fracture, and penetration under high-speed penetration impact, resulting in a severe reduction in overall protective performance and unsatisfactory protective effectiveness. Steel-confined concrete mainly relies on the three-dimensional confinement of the core concrete by the steel pipe to improve its strength, ductility, and toughness, thereby enhancing its overall penetration resistance, but the improvement effect is limited. In addition, existing protective structures have weak resistance to multiple / repeated impacts, and damage from multiple impacts tends to accumulate and spread, seriously affecting the overall protective effectiveness of the structure.

[0003] Therefore, there is an urgent need for a new structure that combines resistance to penetration, resistance to multiple attacks, the ability to induce projectile yaw, and suitability for the protection of large-caliber weapons. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a grating steel pipe-constrained concrete boulders shielding structure and its preparation method. This structure is a protective structure with excellent penetration resistance, strong resistance to multiple / repeated hits, and functions in abrading projectiles and inducing projectile yaw. It also has comprehensive advantages such as simple construction and good economy. The grating steel pipe-constrained concrete boulders shielding structure provided by this invention has a protection mechanism of multiple constraint effects + boulders abrasion energy dissipation + yaw mechanism, specifically reflected in the constraint effect of the steel pipe on the concrete, the synergistic effect between the structural units, and the boulders' abrasion and induced yaw of the projectile.

[0005] To achieve the above objectives, the present invention provides a grid steel pipe constrained boulders concrete shielding structure, comprising a grid steel pipe structure and boulders concrete filled inside the grid steel pipe structure; The grating steel pipe structure includes multiple longitudinal steel plates, multiple transverse steel plates, and an outer frame; Each of the longitudinal steel plates has multiple rectangular slots equally divided along its length, and each of the transverse steel plates also has multiple rectangular slots equally divided along its length; the width of the rectangular slots is the same as the thickness of the steel plates, and the length is half the width of the longitudinal or transverse steel plates. Multiple longitudinal steel plates and multiple transverse steel plates are inserted into each other through the rectangular slots to form multiple square grid units with the same shape and size, and the joints of each slot are fixed by welding to form an internal grid structure. The outer frame is welded to the inserted internal grid structure to form a closed grid steel pipe structure. The rubble concrete includes rubble aggregate and cement-based materials.

[0006] Furthermore, the number and length of the longitudinal steel plates and the transverse steel plates are equal, and the number of equally divided rectangular slots is adapted to the number of steel plates.

[0007] Furthermore, the rectangular slots are formed by laser cutting, and the slots on all longitudinal and transverse steel plates are completely identical in size and position.

[0008] Furthermore, the outer frame is composed of two equilateral L-shaped steel plates welded together. The length of the equilateral L-shaped steel plate is twice the length of the longitudinal or transverse steel plate, and the width of the L-shaped steel plate is the same as the width of the longitudinal or transverse steel plate.

[0009] Furthermore, the stone aggregate is granite, basalt, quartzite or corundum stone with a uniaxial compressive strength of not less than 100 MPa; the stone aggregate is pre-stacked randomly in square grid cells.

[0010] Furthermore, the minimum size of the stone aggregate is not less than 1.5 times the diameter of the penetrating projectile.

[0011] Furthermore, the ratio of the side length of the square grid cell to the diameter of the penetrating projectile is 15 to 25.

[0012] Furthermore, the material of the grating steel pipe structure is carbon structural steel, alloy structural steel, or stainless steel.

[0013] This invention also provides a method for preparing the above-mentioned grid steel pipe confined boulders concrete elastic shielding structure, comprising the following steps: Step 1: Select steel plates that meet the design strength requirements, cut them into plates according to the design dimensions, and divide the plates into longitudinal steel plates and transverse steel plates. Step 2: Each longitudinal and transverse steel plate is equally divided along its length into multiple rectangular slots. The width of the rectangular slot is the same as the thickness of the steel plate, and the length is half the width of the steel plate. The longitudinal and transverse steel plates are then connected by inserting them into the rectangular slots to form multiple square grid units with the same shape and size. The joints of the slots are fixed by welding to form an internal grid structure steel plate. Step 3: Take a steel plate with a length twice that of the inner grid structure steel plate and a width equal to that of the inner grid structure steel plate, and process it into an equilateral L-shaped frame steel plate; Step 4: Weld the two L-shaped frame pieces to the grid structure steel plate to form an integral grid structure; Step 5: After assembling and welding the grating steel pipe structure, pre-pile rubble aggregate into the cavity of the steel pipe; then inject cement-based material into the cavity of the steel pipe under high pressure. Step 6: Perform post-construction maintenance.

[0014] Furthermore, in step five, cement-based material is injected into the cavity of the steel pipe under high pressure. Specifically, a temporary closed pressure-bearing system is first established at both ends of the steel pipe. Then, a flange with a valve is installed at each end of the steel pipe, and a grouting hole is opened at the lower flange. In the initial stage of pouring, the exhaust valve is opened to expel the air in the pipe. After the air is completely expelled, grouting begins from the grouting port at the bottom of the steel pipe. When the cement-based material flows out stably from the exhaust port and has the same properties as the pumped cement-based material, the exhaust valve is closed, grouting is stopped, and the temporary flange device is removed.

[0015] The present invention has the following beneficial effects: (1) This invention provides a grid steel pipe confined rubble concrete bulletproof structure, comprising a grid steel pipe structure and rubble concrete filled inside the grid steel pipe structure; the grid steel pipe structure comprises multiple longitudinal steel plates, multiple transverse steel plates, and an outer frame steel plate; the multiple longitudinal steel plates and multiple transverse steel plates adopt a slot-type grid assembly process, the plates are laser-cut into slots, and are assembled into an internal grid structure by longitudinal and transverse insertion of the slots; the outer frame is made of two equilateral L-shaped steel plates welded together, and is welded together with the internal grid structure to form a grid steel pipe structure; the rubble concrete comprises rubble aggregate and cement-based materials. This bulletproof structure can be assembled in a standardized manner, which facilitates the processing and installation of components, as well as the replacement and repair of the structure after damage. In addition, different protection requirements can be met by adjusting the unit size, steel plate thickness, and rubble gradation.

[0016] (2) The projectile-resistant structure provided by this invention, which is constrained by steel pipe grids and reinforced concrete, exhibits outstanding anti-penetration performance due to the synergistic effect of multiple constraint mechanisms. During projectile penetration, the outer square grid steel pipe units and the core concrete form a synergistic protection system. Furthermore, during projectile penetration, the projectile is not only constrained by the concrete but also by the square grid steel pipe units, while adjacent steel pipe concrete units also exert additional constraints, forming a regional synergistic anti-penetration mechanism that significantly enhances the structure's protective effectiveness.

[0017] (3) The high-strength boulders pre-stacked inside the square grid unit steel pipe in this invention have a dual anti-penetration function: on the one hand, the strength difference between the boulders and the filling cement matrix causes the projectile to generate an asymmetric force during penetration, inducing the projectile to yaw; on the other hand, the high hardness of the boulders is used to achieve the effects of energy dissipation, abrasion, or upsetting of the projectile. In view of the technical problem that relying solely on the passive constraint of the grid unit steel pipe on the concrete has limited effect on improving the overall anti-penetration performance of the structure, this invention stacks high-strength boulders inside the square grid unit steel pipe as a reinforcing medium (i.e., the boulder aggregate is granite, basalt, quartzite, or corundum boulders with a uniaxial compressive strength of not less than 100 MPa). Utilizing their high hardness and high strength characteristics, the boulders-concrete system induces the projectile to yaw or abrade the projectile during penetration, achieving a dual anti-penetration mechanism and significantly improving the anti-penetration performance of the structure.

[0018] (4) This invention takes into account the proportional relationship between the characteristic dimensions of the steel pipe of the grid unit and the diameter of the penetrating projectile, that is, the ratio of the side length of the grid unit to the diameter of the penetrating projectile is 15~25, which maximizes the constraint effect of the steel pipe on the concrete and can resist large-caliber bullets or bunker busters. In addition, this invention relies on the high strength, large size and irregularity of the boulders to dissipate energy and abrade the projectile during the penetration process, so that the projectile is subjected to asymmetrical forces and induces the projectile to yaw. The yaw is mainly achieved by the boulders material. And when the minimum size of the boulders aggregate is not less than 1.5 times the diameter of the penetrating projectile, it has the best protective effect.

[0019] (5) The boulders of the present invention are randomly stacked, and the boulders do not need to be processed into regular cubic modules, which simplifies the construction process; the irregular distribution of the boulder-concrete interface also effectively disrupts the continuity of the penetration process, avoiding the problem of large differences in strength between the interface and the boulders. In addition, the present invention introduces a mechanism for induced projectile yaw and overall structural anti-penetration, which significantly improves the anti-penetration performance of the structure.

[0020] (6) The high-pressure grouting process used in this invention can significantly improve the density of the structure. This process mainly involves drawing a vacuum inside the steel pipe and then using high-pressure grouting to fully fill the gaps between the boulders with cement-based materials, forming a dense steel pipe-constrained boulder concrete structure. This effectively avoids defects such as voids and debonding that are prone to occur in traditional casting processes, not only improving construction efficiency but also ensuring a tight bond between material interfaces and improving the overall quality of the structure. In addition, this invention uses a pre-irregularly stacked boulders + high-pressure grouting process, which is simple; and the steel pipe can be used as a template for stacking boulders and during the casting process. The boulders are readily available and do not require further processing, and the steel plates can be pre-processed in the factory, making construction convenient.

[0021] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the grid steel pipe constrained block stone concrete shielding structure of the present invention; Figure 2 This is a schematic diagram of the internal grid structure of the grid steel pipe constrained concrete shielding structure of the present invention; Figure 3 This is a schematic diagram of the outer frame in the grid steel pipe constrained boulders concrete elastic shielding structure of the present invention; Figure 4 This is a cross-sectional view of the steel pipe confined concrete in the grid steel pipe confined boulders concrete elastic structure of the present invention; Figure 5 This is a schematic diagram of the projectile entering the projectile shielding structure in the grid steel pipe constrained boulders concrete projectile shielding structure of the present invention; Figure 6 This is a construction flowchart of the grid steel pipe constrained block stone concrete elastic shielding structure of the present invention; Among them, 1. longitudinal steel plate, 2. transverse steel plate, 3. outer frame, 4. rubble concrete, 5. rubble aggregate, and 6. cement-based materials. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] See Figures 1 to 4 The present invention provides an anti-penetration grid steel pipe constrained boulders concrete bulletproof structure, including a grid steel pipe structure and boulders concrete 4 filled inside the grid steel pipe structure; The grating steel pipe structure includes multiple longitudinal steel plates 1, multiple transverse steel plates 2, and an outer frame 3; Each of the longitudinal steel plates 1 has multiple rectangular slots equally divided along its length, and each of the transverse steel plates 2 also has multiple rectangular slots equally divided along its length; the width of the rectangular slots is the same as the thickness of the steel plate, and the length is half the width of the steel plate; Multiple longitudinal steel plates 1 and multiple transverse steel plates 2 are inserted into each other through the rectangular slots to form multiple square grid units with the same shape and size, and the joints of each slot are fixed by welding to form an internal grid structure. The outer frame 3 is welded to the inserted internal grid structure to form a closed grid steel pipe structure. The rubble concrete 4 includes rubble aggregate 5 and cement-based material 6. Preferably, the cement-based material 6 is an ultra-high strength cement-based material.

[0025] The number of longitudinal steel plates 1 and transverse steel plates 2 are equal, and the number of equally processed slots is adapted to the number of steel plates.

[0026] The rectangular slots are formed by laser cutting, and the slots on all the longitudinal and transverse steel plates are exactly the same in size and position.

[0027] The outer frame 3 is composed of two equilateral L-shaped steel plates welded together. The side length of the equilateral L-shaped steel plate matches the side length of the outer contour of the internal grid structure, and the thickness of the L-shaped steel plate is the same as the thickness of the steel plate. That is, the length of the equilateral L-shaped steel plate is twice the length of the longitudinal or transverse steel plate, and the width of the L-shaped steel plate is the same as the width of the longitudinal or transverse steel plate.

[0028] The material for the grating steel pipe structure can be carbon structural steel, alloy structural steel, or stainless steel. High-strength, large-sized boulders are placed inside the pipe cavity; these boulders should preferably be high-hardness materials such as granite, basalt, quartzite, or corundum. Then, a cement-based material is poured using a high-pressure grouting process to form a dense steel pipe-constrained boulder concrete structure. The upper and lower surfaces of the grating steel pipe-constrained boulder concrete bullet shield structure provided by this invention are arranged perpendicular to the direction of projectile penetration. When a bullet impacts the bullet shield structure at high speed, the projectile will first contact the concrete part of the bullet shield structure (e.g.,...). Figure 5 (As shown).

[0029] This invention provides a steel-tube grid-constrained concrete bulletproof structure, whose outstanding anti-penetration performance lies in the synergistic effect of multiple constraint effects. During bullet penetration, the outer square grid-unit steel tubes and the core concrete form a collaborative protection system. Furthermore, during bullet penetration, the bullet is not only constrained by the concrete but also by the constraint exerted on the concrete by the grid-unit steel tubes. Simultaneously, adjacent steel-tube concrete units also exert additional constraints, forming a regional collaborative anti-penetration mechanism that significantly enhances the structure's protective effectiveness.

[0030] To address the technical problem that relying solely on the passive constraint of concrete by grid unit steel pipes has limited effect on improving the overall penetration resistance of a structure, this invention uses high-strength boulders (i.e., the boulders are granite, basalt, quartzite, or corundum boulders with a uniaxial compressive strength of not less than 100 MPa) stacked inside square grid unit steel pipes as a reinforcing medium. Utilizing their high hardness and high strength characteristics, the boulders-concrete system abrades the projectile during penetration and induces the projectile to yaw, achieving a dual penetration resistance mechanism and significantly improving the structure's penetration resistance.

[0031] The ratio of the side length of the grid cell to the diameter of the penetrating projectile is 15-25. This maximizes the constraint effect of the steel pipe on the concrete and can withstand large-caliber bullets or bunker buster bombs. Furthermore, this invention relies on the high strength, large size, and irregular shape of the aggregate blocks to dissipate energy and abrade the projectile during penetration, subjecting it to asymmetrical forces and inducing yaw. This yaw is primarily achieved through the aggregate blocks. Optimal protective effect is achieved when the minimum size of the aggregate blocks is not less than 1.5 times the diameter of the penetrating projectile.

[0032] The present invention employs irregularly stacked boulders, eliminating the need for processing them into regular cubic modules, thus simplifying the construction process. The irregular distribution of the boulders-concrete interface also effectively disrupts the continuity of the penetration process, avoiding the problem of significant strength differences between the interface and the boulders. Furthermore, the present invention introduces a mechanism for induced projectile yaw and overall structural synergy in resisting penetration, significantly improving the structure's anti-penetration performance.

[0033] This invention also provides a method for preparing the above-mentioned grid steel pipe confined boulders concrete elastic shielding structure, comprising the following steps: Step 1: Select steel plates that meet the design strength requirements, cut them into plates according to the design dimensions, and divide the plates into longitudinal steel plates and transverse steel plates. Step 2: Each longitudinal and transverse steel plate is equally divided along its length and machined with multiple rectangular slots. The width of the rectangular slots is the same as the thickness of the steel plate, and the length is half the width of the steel plate. The longitudinal and transverse steel plates are then connected by inserting them into the rectangular slots to form multiple square grid units with the same shape and size. The joints of the slots are welded together to form an internal grid structure steel plate. Step 3: Take a steel plate with a length twice that of the grid structure steel plate and a width equal to that of the grid structure steel plate, and process it into an equilateral L-shaped frame steel plate; Step 4: Weld the two L-shaped frame pieces to the grid structure steel plate to form an integral grid structure; Step 5: After assembling and welding the grating steel pipe structure, pile up the stone aggregate in the cavity of the steel pipe; then inject cement-based material into the cavity of the steel pipe under high pressure. Step 6: Perform post-construction maintenance.

[0034] like Figure 6 As shown, taking a grid pattern of nine square grid units as an example, the specific manufacturing process of a grid steel pipe constrained concrete elastic shielding structure is as follows: Step 1: Select steel plates that meet the design strength requirements and cut them into plates according to the design dimensions. The length, width, and thickness tolerances of the steel plates should be controlled within ±0.5 mm. After cutting, the cut edges of the plates are machined to eliminate cutting defects such as heat-affected zones, hardened layers, or microcracks. Step 2: At 1 / 3 and 2 / 3 of the length of the steel plate, use laser cutting to create precision slots. The slots should be the same width as the plate thickness and half the width of the plate. The cutting accuracy should be controlled so that the width error of the cut does not exceed ±0.1mm. Step 3: Connect the four slotted steel plates through slots to form a grid structure, and weld them together at the joints of the slots to ensure that the misalignment of the nodes is no more than 1.5mm. Step 4: Take a steel plate with a length twice that of the grid structure steel plate and a width that is the same as the width of the grid structure steel plate. Process it into an equilateral L-shaped frame steel plate using a CNC bending machine. When bending, a bending amount of 0.5°~1° should be preset to compensate for the springback, so as to ensure that the angle deviation after forming is not greater than ±0.5° and the bending radius error is not more than 0.1 times the plate thickness. Step 5: Weld the two L-shaped frame pieces to the "well" shaped grid structure to form an integral grid structure. All welds should be full penetration butt welds, located at the connection between the frame and the grid structure and at the frame joints. The distance between adjacent welds should be greater than 300 mm. Step 6: After assembling and welding the grating steel pipe structure, place high-strength, large-sized stones inside the steel pipe cavity. The stones should preferably be high-hardness stones such as granite, basalt, quartzite, or corundum, with a uniaxial compressive strength of not less than 100 MPa, and the minimum size of the stones should not be less than 1.5 times the diameter of the penetrating projectile. Step 7: Establish a temporary closed pressure system at both ends of the steel pipe: Install a flange with a valve at each end of the steel pipe, with a grouting hole to be opened at the lower flange; at the beginning of the pouring, open the vent valve to release the air in the pipe; after the air is completely released, start grouting from the grouting port at the bottom of the steel pipe; when the cement-based material flows out steadily from the vent and has the same properties as the pumped cement-based material, close the vent valve, stop grouting, and remove the temporary flange device. Step 8: Perform proper maintenance afterwards.

[0035] The high-pressure grouting process employed in this invention significantly improves the density of the structure. This process primarily involves creating a vacuum inside a steel pipe, followed by high-pressure grouting to fully fill the gaps between the boulders with cement-based material, forming a dense steel-pipe-constrained boulder concrete structure. This effectively avoids defects such as voids and debonding that are common in traditional casting processes, improving construction efficiency and ensuring a tight bond between material interfaces, thus enhancing the overall structural quality. Furthermore, this invention employs a pre-arranged irregular stacking of boulders combined with high-pressure grouting, simplifying the process. The steel pipe serves as a template for both boulder stacking and casting; the boulders are readily available and require no further processing; and the steel plates can be pre-processed in the factory, making construction convenient.

[0036] The anti-penetration mechanism of this invention is based on the synergistic effect of multiple constraint effects. During the projectile penetration process, the constraint effect of concrete on the projectile, the constraint effect of steel pipe on its core concrete, and the additional constraints provided by adjacent units form a regional synergistic anti-penetration mechanism, which significantly increases the penetration resistance of the projectile, reduces the penetration depth of the projectile, effectively limits damage propagation, and improves the anti-penetration performance of the structure. In this invention, the high-strength boulders pre-stacked inside the square grid unit steel pipe have a dual anti-penetration function: on the one hand, the discontinuous distribution of the boulders-cement matrix interface and the strength difference between the boulders and the filling cement matrix induce asymmetric forces in the projectile, causing it to "yaw"; on the other hand, the steel pipe constrains the boulders in the concrete structure, subjecting it not only to the constraint provided by the concrete but also to the constraint effect exerted by the outer steel pipe and the additional constraint exerted by the surrounding steel pipe concrete units, placing it under triaxial compression, significantly improving the strength, ductility, and toughness of the boulders, thereby enhancing the overall anti-penetration performance. The boulders should preferably be high-hardness materials such as granite, basalt, quartzite, or corundum, with a uniaxial compressive strength of not less than 100 MPa. The minimum size of the boulders should not be less than 1.5 times the diameter of the penetrating projectile, and the gradation between the boulders should be considered. The ratio of the characteristic dimension of the grid steel pipe (i.e., the side length of the square grid unit) to the diameter of the penetrating projectile should preferably be between 15 and 25. The external steel pipe material can be selected from carbon structural steel or alloy structural steel, or stainless steel, depending on the project requirements, to meet the protection needs of special areas. The bullet shielding structure of this invention has high adaptability. According to the requirements of the diameter of the protected weapon bullet, different protection needs can be matched by adjusting the pipe wall thickness, cross-sectional dimensions, and the gradation and size of the stones.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 grid steel pipe constrained concrete block shielding structure, characterized in that, Includes a grid steel pipe structure and rubble concrete filling the interior of the grid steel pipe structure; The grating steel pipe structure includes multiple longitudinal steel plates, multiple transverse steel plates, and an outer frame; Each of the longitudinal steel plates has multiple rectangular slots equally divided along its length, and each of the transverse steel plates also has multiple rectangular slots equally divided along its length; the width of the rectangular slots is the same as the thickness of the steel plates, and the length is half the width of the longitudinal or transverse steel plates. Multiple longitudinal steel plates and multiple transverse steel plates are inserted into each other through the rectangular slots to form multiple square grid units with the same shape and size, and the joints of each slot are fixed by welding to form an internal grid structure. The outer frame is welded to the inserted internal grid structure to form a closed grid steel pipe structure. The rubble concrete includes rubble aggregate and cement-based materials.

2. The grid steel pipe constrained boulders concrete elastic shielding structure according to claim 1, characterized in that, The number and length of the longitudinal steel plates and the transverse steel plates are equal, and the number of equally processed rectangular slots matches the number of steel plates.

3. The grid steel pipe constrained boulders concrete elastic shielding structure according to claim 1, characterized in that, The rectangular slots are formed by laser cutting, and the slots on all the longitudinal and transverse steel plates are exactly the same in size and position.

4. The grid steel pipe constrained boulders concrete elastic shielding structure according to claim 2, characterized in that, The outer frame is composed of two equilateral L-shaped steel plates welded together. The length of the equilateral L-shaped steel plate is twice the length of the longitudinal or transverse steel plate, and the width of the L-shaped steel plate is the same as the width of the longitudinal or transverse steel plate.

5. A grid steel pipe confined concrete bulletproof structure according to claim 1, characterized in that, The stone aggregate is made of granite, basalt, quartzite or corundum blocks, with a uniaxial compressive strength of not less than 100 MPa; the stone aggregate is pre-stacked randomly in square grid cells.

6. The grid steel pipe constrained boulders concrete elastic shielding structure according to claim 1, characterized in that, The minimum size of the stone aggregate is not less than 1.5 times the diameter of the penetrating projectile.

7. The grid steel pipe constrained boulders concrete elastic shielding structure according to claim 1, characterized in that, The ratio of the side length of the square grid cell to the diameter of the penetrating projectile is 15 to 25.

8. A grid steel pipe confined concrete bulletproof structure according to claim 1, characterized in that, The material of the grating steel pipe structure is carbon structural steel, alloy structural steel or stainless steel.

9. A method for preparing a grid steel pipe confined boulders concrete elastic shielding structure according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Select steel plates that meet the design strength requirements, cut them into plates according to the design dimensions, and divide the plates into longitudinal steel plates and transverse steel plates. Step 2: Process multiple rectangular slots equally along the length of each longitudinal and transverse steel plate. The width of the rectangular slot is the same as the thickness of the steel plate, and the length is half the width of the steel plate. Then, insert the longitudinal and transverse steel plates into the rectangular slots to form multiple square grid units with the same shape and size. The joints of the slots are fixed by welding to form an internal grid structure steel plate. Step 3: Take a steel plate with a length twice that of the inner grid structure steel plate and a width equal to that of the inner grid structure steel plate, and process it into an equilateral L-shaped frame steel plate; Step 4: Weld the two L-shaped frame pieces to the grid structure steel plate to form an integral grid structure; Step 5: After assembling and welding the grating steel pipe structure, pre-pile rubble aggregate into the cavity of the steel pipe; then inject cement-based material into the cavity of the steel pipe under high pressure. Step 6: Perform post-construction maintenance.

10. The preparation method according to claim 9, characterized in that, In step five, cement-based material is injected into the cavity of the steel pipe under high pressure. Specifically, a temporary closed pressure system is first established at both ends of the steel pipe. Then, a flange with a valve is installed at each end of the steel pipe, and a grouting hole is opened at the lower flange. In the initial stage of pouring, the exhaust valve is opened to expel the air in the pipe. After the air is completely expelled, grouting begins from the grouting port at the bottom of the steel pipe. When the cement-based material flows out steadily from the exhaust port and has the same properties as the pumped cement-based material, the exhaust valve is closed, grouting is stopped, and the temporary flange device is removed.

Images