A construction method for energy absorption and buffering structure of slide rail test system

Abstract

The invention discloses a construction method of an energy absorption buffer structure of a slide rail test system, comprising the following steps: S1: foundation pile construction: leveling the site, measuring and setting out, drilling, installing a steel cage, and pouring a pile foundation; S2: anchor cable construction: excavating a foundation pit, measuring and setting out, drilling, installing an anchor cable and grouting and anchoring; S3: cushion layer construction: measuring and setting out the edge line, excavating a foundation pit, cleaning the pile foundation pile head, installing a template, and pouring to form a cushion layer; S4: cap construction: setting out the edge line and center line of the cap, tying steel bars, installing a template, pouring to form a cap, prestressing the anchor cable, and sealing and fixing the anchor in the cap; S5: wall body construction: setting out the side line of a C-shaped wall, tying steel bars, installing a template, and pouring a C-shaped wall; S6: buffer stacking: stacking sandbags within the range of the C-shaped wall body. The buffer structure constructed by this method has the advantages of strong impact resistance, high reliability, and reduced damage to the test trolley and safety risks of operation.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a construction method of an energy absorption and buffering structure of a slide rail test system. Background Art

[0002] The large aircraft ground dynamics test platform is the first test platform in the relevant field in China. It is of great significance and far-reaching impact. After completion, it will test various aircraft tires, wheel brakes, landing gear systems, high-speed dynamic characteristics on different pavement surfaces and large side slip angle dynamic characteristics on real runways, and collect basic data.

[0003] The test platform uses a test rig running on a slide rail test line to simulate a large aircraft for dynamic ground testing. To ensure safety during the test, a buffer structure is required to be set up at the end of the test line to effectively stop the out-of-control test rig. The test rig can run at a maximum speed of 406 kilometers per hour, and the kinetic energy generated is enormous. Therefore, very high requirements are placed on the buffer structure's ability to resist horizontal impacts and energy consumption. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a construction method for an energy-absorbing and buffering structure of a slide rail test system with a stable structure and strong impact resistance.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A construction method for an energy absorption and buffering structure of a slide rail test system comprises the following steps:

[0007] S1: Foundation pile construction: level the site, measure and mark out the center of the pile position, use a drilling rig to drill holes, clean the holes after drilling, then install the steel cage, pour concrete and cast the pile foundation;

[0008] S2: Anchor cable construction: excavate the foundation pit, measure and lay out the hole coordinates, use a drilling rig to drill holes, install anchor cables and grouting after the holes are formed;

[0009] S3: Pad construction: After measuring and setting out the pad edge, excavate the foundation pit, break and clean the pile head, then install the formwork and pour concrete to form the pad;

[0010] S4: Cap construction: After the cushion concrete reaches the designed strength, the edge and center lines of the cap are laid out, the steel bars are tied, the formwork is installed, and the concrete is poured to form the cap. At the same time, the anchor cables are prestressed and anchored in the cap;

[0011] S5: Wall construction: Use a total station to lay out the C-shaped wall sideline on the foundation, then set up scaffolding, tie steel bars, install formwork, and pour concrete to form a C-shaped wall;

[0012] S6: Buffer stacking: After the C-shaped wall reaches the designed strength, sandbags are stacked within the wall and protected by wire mesh.

[0013] As a further improvement of the above technical solution:

[0014] In step S1, a steel casing is buried manually with an excavator according to the center of the pile position, and a grouting hole is opened on the upper part of the steel casing.

[0015] In step S1, a mud pool is set up on site, and mud is continuously added to the hole during drilling construction.

[0016] The mud is prepared from high plastic clay or bentonite.

[0017] In step S4, the foundation is cast in two layers, and after the first layer of the foundation reaches the designed strength, the anchor cables are tensioned, tested and sealed.

[0018] In step S4, the anchor cable after being sealed and fixed forms an angle of 30° with the horizontal plane.

[0019] In step S5, an impact-resistant wall is cast behind the C-shaped wall.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] The construction method of the energy-absorbing and buffering structure of the slide rail test system of the present invention adopts a pile-cap structure composed of a pile foundation and a cap, which has a stable structure and high strength, and is provided with anchor cables for prestressed tensioning and anchoring, has strong horizontal impact resistance and high reliability, and is provided with a cushion layer for leveling to ensure a horizontal construction plane. Sandbags are stacked in a C-shaped wall to form a buffer for the test trolley, absorb the remaining kinetic energy of the test trolley, and achieve the purpose of deceleration. While effectively intercepting the test trolley, the degree of damage and the safety risks during the test process are reduced, thereby preventing the test trolley from derailing and damaging surrounding facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a construction flow chart of the present invention.

[0023] Figure 2 It is a schematic diagram of the energy absorbing and buffering structure of the present invention.

[0024] Figure 3 Schematic diagram of the energy-absorbing and buffering structure of the present invention (from another perspective).

[0025] The symbols in the figure represent:

[0026] 1. Pile foundation; 2. Anchor cable; 3. Capping platform; 4. C-shaped wall; 5. Impact wall. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figures 1 to 3 As shown, the construction method of the energy absorption and buffering structure of the slide rail test system of this embodiment includes the following steps:

[0029] S1: Foundation pile construction: level the site, measure and mark out the center of the pile position, use a drilling rig to drill holes, clean the holes after drilling, then install the steel cage, pour concrete and cast the pile foundation 1;

[0030] S2: Anchor cable construction: excavate the foundation pit, measure and lay out the hole coordinates, use a drilling rig to drill holes, install anchor cable 2 after the holes are formed and grout anchor;

[0031] S3: Cushion construction: After measuring and setting out the cushion edge, excavate the foundation pit, break and clean the pile head of pile foundation 1, then install the formwork and pour concrete to form the cushion;

[0032] S4: Cap construction: After the cushion concrete reaches the designed strength, the edge line and center line of the cap 3 are laid out, the steel bars are tied, the formwork is installed, and the concrete is poured to form the cap 3. At the same time, the anchor cable 2 is prestressed and anchored in the cap 3;

[0033] S5: Wall construction: Use a total station to lay out the side line of the C-shaped wall 4 on the cap 3, then set up scaffolding, tie steel bars, install formwork, and pour concrete to form the C-shaped wall 4;

[0034] S6: Buffer stacking: After the C-shaped wall 4 reaches the designed strength, sandbags are stacked within the wall and protected by wire mesh.

[0035] The method adopts a pile-cap structure composed of a pile foundation 1 and a cap 3, which has a stable structure and high strength, and is provided with an anchor cable 2 for prestressed anchoring, which has strong resistance to horizontal impact and high reliability. A cushion layer is provided for leveling to ensure a horizontal construction plane, and sandbags are stacked in a C-shaped wall 4 to form a buffer for the test trolley and absorb the remaining kinetic energy of the test trolley to achieve the purpose of deceleration. While effectively intercepting the test trolley, the degree of damage and the safety risks during the test process are reduced, thereby preventing the test trolley from derailing and damaging surrounding facilities.

[0036] In this embodiment, in step S1, a steel casing is buried manually with an excavator according to the center of the pile position, and a grouting hole is opened on the upper part of the steel casing. The pile position of the steel casing is positioned and the grouting hole is set on the steel casing to prevent the mud from leaking at the bottom of the steel casing.

[0037] In this embodiment, the steel casing is rolled with a steel plate with a thickness of 12mm to ensure sufficient strength and rigidity. The inner diameter is 100mm larger than the pile diameter, which is Φ1100mm. The casing is 2m long and has 1-2 overflow holes on the top. The casing is buried manually with an excavator according to the pre-arranged design pile position center, and the verticality of the casing should be strictly maintained. The top is 50cm above the ground. Clay soil is backfilled and compacted in layers at the bottom and around the outside of the casing. When underwater construction is required, the length of the casing is determined according to the actual situation. The bottom end of the hole casing should be buried in a watertight stable layer. When the hole casing is buried in unstable surface soil, the surrounding area should be replaced with soil or pre-treated. After the casing is buried, the deviation between the center of the casing and the center of the design pile position is measured with a total station and a calibrated steel ruler, and the plane size and verticality deviation are checked with a plumb bob and a steel ruler.

[0038] In this embodiment, in step S1, a mud pool is set up on site, and mud is continuously added to the hole during drilling construction. The water head in the steel casing is maintained by continuous grouting to prevent the hole wall from collapsing.

[0039] In this embodiment, before drilling, the drilling rig must ensure that the base is stable when it is in place, and the verticality of the drill rod and the horizontality of the frame platform must be controlled to ensure that the drill rod and the center of the casing are on a vertical line, and the deviation is controlled within 2 cm. After the drilling rig is in place, the top elevation of the casing is remeasured as a basis for measuring the hole depth and sediment thickness in the future. According to the position of each pile, a mud pool is arranged on site for the discharge and storage of mud to minimize the pollution caused by mud circulation. The mud pool is maintained with steel pipes all around, painted with red and white paint, set up safety warning signs and installed with dense mesh vertical nets.

[0040] In this embodiment, the mud is prepared by high plasticity clay or bentonite. The slurry is made by high-quality bentonite and carboxymethyl cellulose. High-quality bentonite is prepared before the pile is piled, and the mud ratio is determined to be water: bentonite = 980Kg: 35Kg according to the test. The slurry is made by excavator and mud pump in the mud pool by self-circulation. The mud is adjusted appropriately according to the geological conditions, and the mud performance is adjusted at any time according to the changes in soil quality. The fresh mud index is generally: relative specific gravity 1.04-1.10, sand content ≤1%, viscosity 18-30, and the export mud index is generally: relative specific gravity 1.1-1.2, sand content ≤4%, viscosity 18-30. During the drilling process, the performance of the mud in the hole is tested at any time, and records are kept. If it does not meet the requirements, it should be adjusted in time. Mud index testing must be carried out at geological changes and during shift changes. In order to ensure the quality of the pile foundation 1, slurry is made in the mud pool, and slurry in the hole is strictly prohibited. The drilling mud is recycled and reused to reduce the amount of discharge. After the construction is completed, the waste mud is first concentrated and then treated. It is strictly forbidden to discharge it at will to pollute the environment and waters.

[0041] Commercial concrete is used for pouring pile foundation 1, with a concrete strength of C30, a concrete mix ratio of cement 1: water 0.36: sand 3.42: stone 3.32, a slump of 180-200mm, and a diffusion of 340-380mm. In order to improve work efficiency, this construction uses a concrete tank truck for direct concrete pouring, with the conduit connected for 25-30 meters at a time, and the continuous pouring pile top elevation should be at least 0.5m higher than the design elevation.

[0042] In this embodiment, in step S2, the anchor cable 2 is formed by 3 steel strands, the free section of the anchor cable 2 is treated with anti-corrosion, wrapped with a plastic tube, and the plastic tube mouth at the intersection with the anchor section should be sealed and tied with lead wire. The anchor grouting of the anchor cable 2 adopts a secondary grouting method, one normal pressure grouting and one high pressure grouting.

[0043] In this embodiment. In step S3, after the pile head of the pile foundation 1 is cut off, the bottom of the foundation pit is manually cleaned to the design elevation and then leveled with a 10cm thick C15 plain concrete cushion layer using a steel mold. The top surface is not higher than the base elevation, and the edge of the cushion layer is 20-30cm larger than the size of the platform. The template uses a 10cm thick channel steel. After the template is installed, the elevation of the top of the template is consistent with the elevation of the top of the cushion layer. The outside is fixed and supported by steel bars. The joints are tight and the line shape is straight. The concrete is poured using a truck crane batching hopper. During pouring, the concrete is vibrated and compacted, and the whole is flat. After the concrete is poured, a plastic film is covered on the concrete surface and watered for maintenance to ensure that the concrete surface is always in a moist state. Clean tap water should be used for maintenance, and the maintenance period is generally 2-3 days.

[0044] In this embodiment, in step S4, the cap 3 is cast in two layers, and the anchor cable 2 is anchored and fixed after the first layer of the cap 3 reaches the design strength. The cap 3 is cast in layers to avoid cold joints. After the cushion layer is constructed, the edge line and center line of the cap are laid out and the cushion layer elevation is measured. Before tying the steel bars of the cap 3, the plane position of each bottom steel bar is marked on the cushion layer, and the steel bars are accurately placed and tied. After the steel bars are tied and installed, the stiffness and strength of the formwork meet the requirements of the specification. After the template is installed, the linearity is straight, and the steel template is brushed with a release agent, the joints are tight, and the support is firm.

[0045] After the first layer of the cap 3 is poured, the anchor strength of the prestress of the anchor cable 2 is tested, the prestressed anchor cable is tensioned and locked, the loss of the prestress of the anchor cable is tested, and finally the anchor is sealed. Then the second layer of the cap 3 is poured.

[0046] In this embodiment, in step S4, the anchor cable 2 after being sealed and fixed forms an angle of 30° with the horizontal plane.

[0047] In this embodiment, in step S5, an anti-impact wall 5 is also cast behind the C-shaped wall 4. The anti-impact wall 5 enhances the ability of the C-shaped wall 4 to resist impact and improves the stability of the structure.

[0048] In step S5, the concrete of the C-shaped wall 4 is poured and compacted in layers to ensure the bonding degree of the upper and lower layers of concrete before initial setting and avoid the formation of cold joints. To avoid segregation during concrete pouring, the free fall height of the concrete from a height is not more than 2 meters. Concrete vibration: Use a φ50 inserted vibrator. When vibrating, insert quickly and pull out slowly. The insertion points should be evenly arranged, moved point by point, and carried out in sequence without omission to ensure uniform vibration. The movement of the vibrator adopts a "determinant" movement spacing of no more than 400mm. At the same time, in order to avoid cold joints in the concrete, when vibrating the upper layer of concrete, it should be inserted into the lower layer by 50 to 100mm to eliminate the joints between the two layers.

[0049] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A construction method for an energy absorption and buffering structure of a slide rail test system, characterized in that: The following steps are involved: S1: Construction of foundation piles: leveling the site, measuring and marking out the center of the pile position, drilling with a drilling rig, cleaning the hole after drilling, installing the steel cage, pouring concrete to build the pile foundation (1), burying the steel casing manually with an excavator according to the center of the pile position, and opening a grouting hole on the top of the steel casing; S2: Anchor cable construction: excavate the foundation pit, measure and lay out the hole coordinates, use a drilling rig to drill holes, install the anchor cable (2) after the holes are drilled, and grout the anchors; S3: Cushion construction: After measuring and setting out the cushion boundary, excavate the foundation pit, break and clean the pile head of the pile foundation (1), then install the formwork and pour concrete to form the cushion; S4: Cap construction: After the cushion concrete reaches the design strength, the edge line and center line of the cap (3) are laid out, the steel bars are tied, the formwork is installed, and the concrete is poured to form the cap (3). At the same time, the anchor cable (2) is prestressed and anchored in the cap (3). The cap (3) is cast in two layers. After the first layer of the cap (3) reaches the design strength, the anchor cable (2) is tensioned, tested and anchored; S5: Wall construction: Use a total station to lay out the sideline of the C-shaped wall (4) on the pedestal (3), then set up scaffolding, tie steel bars, install formwork, and pour concrete to form the C-shaped wall (4). An impact-resistant wall (5) is also poured behind the C-shaped wall (4); S6: Buffer stacking: After the C-shaped wall (4) reaches the designed strength, sandbags are stacked within the wall and protected with wire mesh.

2. The construction method of the energy absorption and buffering structure of the slide rail test system according to claim 1 is characterized in that: In step S1, a mud pool is set up on site, and mud is continuously added to the hole during drilling construction.

3. The construction method of the energy absorption and buffering structure of the slide rail test system according to claim 2 is characterized in that: The mud is prepared from high plastic clay or bentonite.

4. The construction method of the energy absorption and buffering structure of the slide rail test system according to claim 1 is characterized in that: In step S4, the anchor cable (2) after being sealed and fixed forms an angle of 30° with the horizontal plane.

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