Experimental method of beam column type target guardrail structure and beam column type target guardrail structure

Abstract

The invention discloses an experimental method of a beam column type target guardrail structure and the beam column type target guardrail structure. The experimental method of the beam column type target guardrail structure comprises the steps that 1, a plurality of original guardrail structures are obtained; 2, simulating the disturbance degree of the structural parameters of the original guardrail structure to the flow field, and screening to obtain a primarily screened guardrail structure based on a set mode; 3, the anti-collision performance of the structural parameters of the primary screening guardrail structure is simulated, and the guardrail structure meeting the target safety protection level is screened to serve as a secondary screening guardrail structure; 4, verifying the disturbance degree of the flow field by the second sieve guardrail structure through a wind tunnel experiment mode; and 5, a real collision simulation experiment is adopted for the second-sieve guardrail structure verified through the wind tunnel experiment, and the second-sieve guardrail structure meeting the target safety protection level is obtained to serve as the target guardrail structure.

Description

Technical Field

[0001] This invention relates to the field of road safety engineering technology, specifically to an experimental method for a beam-column type target guardrail structure and the beam-column type target guardrail structure itself. Background Technology

[0002] In areas prone to blowing snow and sand, traditional guardrail structures significantly impede the flow of snow and sand, easily causing snow and sand accumulation on road sections and leading to traffic accidents. While cable-stayed guardrails reduce this obstruction, they have large deformation capacity and relatively weak protective capabilities, with the highest safety protection level only at SB level, which cannot meet the protection requirements of high-grade highways. Summary of the Invention

[0003] The purpose of this invention is to provide an experimental method for a beam-column type target guardrail structure and a beam-column type target guardrail structure. Through the improvement of the experimental method for the beam-column type target guardrail structure, the beam-column type target guardrail structure can meet the requirements of target ventilation rate and target safety protection level.

[0004] To achieve the above objectives, the present invention provides an experimental method for a beam-column type target guardrail structure, the experimental method comprising: Step 1: Obtain several original guardrail structures; Step 2: Simulate the degree of disturbance of the flow field by the structural parameters of the original guardrail structure, and select the initial guardrail structure based on the set method; Step 3: Simulate the anti-collision performance of the structural parameters of the initial screening guardrail structure, and select those that meet the target safety protection level as the second screening guardrail structure; Step 4: Verify the degree of disturbance of the flow field by the two-screen guardrail structure through wind tunnel experiments; Step 5: Using a real collision simulation experiment, the two-screen guardrail structure verified by the wind tunnel experiment is used to obtain the target guardrail structure that meets the target safety protection level.

[0005] By adopting the technical solution of this application, the original guardrail structure is screened through simulation technology, wind tunnel experiments, and actual impact testing to obtain the target guardrail structure, thereby achieving a target guardrail structure that meets the target safety protection level and target wind permeability. Based on this experimental method, a target guardrail structure suitable for high-grade highways facing wind-blown snow and sandstorm disasters can be developed.

[0006] Optionally, the original guardrail structure includes tubular parameters and the number of crossbeams; the degree of disturbance of the flow field by the structural parameters simulating the original guardrail structure includes: CFD simulation was used to simulate the degree of disturbance of the flow field by the structural parameters of the original guardrail structure.

[0007] Optionally, the structural parameters of the original guardrail structure include the first tubular parameters; The degree of disturbance of the flow field by the structural parameters of the original guardrail structure simulated by CFD simulation includes the first wind speed region index corresponding to the first tube type parameter, and the simulated amount of the first wind speed is less than or equal to the starting wind speed of the set material. The setting methods include: Step 2.11: Based on the negative correlation between the degree of disturbance of the flow field and the air permeability of the guardrail structure, the tube parameters of the guardrail structure that meet the target degree of flow field disturbance are selected as the initial screening parameters.

[0008] Optionally, the structural parameters of the original guardrail structure include the first crossbeam quantity parameter, and the degree of disturbance of the flow field by the structural parameters of the original guardrail structure to the flow field by CFD simulation includes the second wind speed region index corresponding to the first crossbeam quantity parameter, the simulated amount of the second wind speed is greater than the starting wind speed of the set substance, and the overlap index between the second wind speed region index and the set road surface index. The setting methods include: Step 2.12: Based on the positive correlation between the overlap index and the air permeability, select those that meet the target flow field disturbance level as the initial screening parameter for the number of beams of the guardrail structure.

[0009] Optionally, the anti-collision performance of the structural parameters of the simulated primary screening guardrail structure includes: The collision resistance performance of the initial screening guardrail structure was simulated using finite element method (FEM) collision experiments.

[0010] Optionally, the wind tunnel experiment includes at least one of an empty wind tunnel experiment and a medium accumulation comparison experiment.

[0011] Optionally, the target security protection level is SA level.

[0012] Optionally, the target tube shape parameter is a flat ellipse.

[0013] Optionally, the number of target beams is 3; the column spacing of the target guardrail structure is 3m.

[0014] The beam-column type target guardrail structure includes several horizontal beams arranged vertically in sequence and columns for supporting the horizontal beams. The cross-section of each horizontal beam is a flat ellipse. Each horizontal beam includes a narrow side portion. The narrow side portion of the horizontal beam and the column are opposite to and fixedly connected to each other along the thickness direction of the target guardrail structure.

[0015] The beam-column target guardrail structure obtained through the aforementioned experimental method, using a flat elliptical column and beam structure, can achieve the target safety protection level and the target ventilation rate of the target guardrail structure; it can meet the protection level requirements of high-grade highways located in windy snow and windy sand areas, and can also reduce or avoid the problems of snow and sand accumulation.

[0016] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0018] Figure 1 This is one of the experimental methods for the beam-column type target guardrail structure in the implementation method; Figure 2 This is the second experimental method for the beam-column type target guardrail structure in the implementation method; Figure 3 This is the third experimental method for the beam-column type target guardrail structure in the implementation plan; Figure 4 This is the fourth experimental method for the beam-column type target guardrail structure in the implementation plan; Figure 5 It is one of the CFD simulations of flow field for the first tube type parameters; Figure 6 This is the second CFD simulation of the flow field for the first tube type parameter; Figure 7 This is the third CFD simulation of the flow field for the first tube type parameter; Figure 8 This is the fourth CFD simulation of the flow field for the first tube type parameter; Figure 9 This is the fifth CFD simulation of the flow field for the first tube type parameter; Figure 10 It is one of the CFD simulation flow field simulations of the first crossbeam quantity parameter; Figure 11 This is the second part of the CFD simulation of the flow field for the first crossbeam quantity parameter; Figure 12 This is a schematic diagram of the target guardrail structure in an embodiment of the present invention; Figure 13 yes Figure 12 A top view of a partial structure; Figure 14 yes Figure 13 A magnified schematic diagram of a local structure; Figure 15 yes Figure 1 One of the side views; Figure 16 yes Figure 15 A magnified schematic diagram of a local structure; Figure 17 yes Figure 12 The second side view.

[0019] Figure label: 1-Column; 11-Pile segment; 21-First crossbeam; 22-Second crossbeam; 23-Third crossbeam; 24-Beam segment; 3-Connecting sleeve; 4-Anti-blocking block; 41-First connecting section; 42-Second connecting section; 43-Transition section; 51a-First long side; 51b-First narrow side; 52a-Second long side; 52b-Second narrow side; 6-Delineator; 7-Anti-glare plate. Detailed Implementation

[0020] This invention provides an experimental method for a beam-column type target guardrail structure and a beam-column type target guardrail structure. Through improvements to the experimental method for the beam-column type target guardrail structure, the beam-column type target guardrail structure can meet the requirements of target ventilation rate and target safety protection level.

[0021] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0023] In areas prone to blowing snow and sand, traditional rigid guardrail structures significantly impede snow and wind flow, easily causing snow accumulation on roads, leading to traffic accidents and posing a significant threat to traffic safety. Specifically, the air permeability of SA-grade concrete F-type guardrail structures is 0%, while SA-grade corrugated beam guardrails have an air permeability of 52%. In some snow-blocked road sections, SA-grade beam-column guardrails used at bridge approach ramps have an air permeability of 56%, all resulting in significant sand and snow obstruction. In areas prone to sand and snow damage, guardrails, due to their disturbance of the near-surface airflow, can even become a major cause of road blockage.

[0024] Another type of rope guardrail has a ventilation rate of over 85%, and the rate and scale of sand and snow accumulation are relatively much smaller. However, due to its special flexible structure, its impact resistance is severely limited, and it can only reach the SB level of safety protection, making it difficult to use on high-grade highways.

[0025] Air permeability refers to the ability of a fence structure to allow natural elements such as wind, snow, or sand to pass through it, usually expressed as a percentage. Specifically, air permeability reflects the ratio of the area of ​​the openings perpendicular to the airflow direction to the total area of ​​the fence structure. A higher air permeability indicates less obstruction of wind, snow, or sand, allowing more natural elements to pass through; conversely, a lower air permeability indicates greater obstruction.

[0026] To achieve the above objectives, such as Figure 1 As shown, Figure 1 This is one of the experimental methods for the beam-column type target guardrail structure in the embodiments of this application; This invention provides an experimental method for a beam-column type target guardrail structure, the experimental method comprising: Step 1: Obtain several original guardrail structures; Step 2: Simulate the degree of disturbance of the flow field by the structural parameters of the original guardrail structure, and select the initial guardrail structure based on the set method; Step 3: Simulate the anti-collision performance of the structural parameters of the initial screening guardrail structure, and select those that meet the target safety protection level as the second screening guardrail structure; Step 4: Verify the degree of disturbance of the flow field by the two-screen guardrail structure through wind tunnel experiments; Step 5: Using a real collision simulation experiment, the two-screen guardrail structure verified by the wind tunnel experiment is used to obtain the target guardrail structure that meets the target safety protection level.

[0027] By adopting the technical solution of this application, the original guardrail structure is screened by using simulation technology, wind tunnel experiments and actual impact tests to obtain the target guardrail structure, thereby obtaining a target guardrail structure that meets the target safety protection level and the target ventilation rate.

[0028] Based on this experimental method, a target guardrail structure suitable for high-grade highways in areas facing wind-blown snow and sandstorm disasters can be developed.

[0029] In step 1, the original guardrail structure can be selected using parameters from a common beam-column target guardrail structure. It can be determined that the structural parameters of the guardrail structure typically include pipe type parameters, the number of crossbeams, and the post spacing parameters. It also includes the dimensions of the pipe cross-section, which are within a set range. The number of crossbeams refers to the number of crossbeams arranged along the height direction of the target guardrail structure.

[0030] In a specific example, the pipe cross-sectional dimensions were tested in this experimental method with a pipe cross-sectional perimeter of 300mm ± 50mm.

[0031] The original guardrail structure is defined by the following parameters: the tubular type parameter is called the first tubular type parameter, the number of crossbeams is called the first crossbeam number parameter, and the post spacing parameter is called the first post spacing parameter. The first tubular type parameter can include square tubing, rectangular tubing, elliptical tubing, round tubing, and flat elliptical tubing, etc. Those skilled in the art can also select other first tubular type parameters for experimentation according to actual needs. The number of first crossbeams is 3 or 4.

[0032] The first post spacing parameter refers to the distance between two adjacent posts in the extension direction of the target guardrail structure. Commonly used post spacing parameters are 2m, 3m or 4m, so the first post spacing parameter is 2m, 3m or 4m.

[0033] In step 2, the structural parameters of the original guardrail structure are simulated to simulate the degree of disturbance to the flow field, and a preliminary guardrail structure is obtained based on the set method.

[0034] Specifically, the degree of flow field disturbance refers to the extent to which the guardrail structure affects the surrounding airflow (flow field). Air permeability, as an indicator negatively correlated with the degree of flow field disturbance, is introduced in this embodiment. The higher the air permeability, the lower the degree of flow field disturbance caused by the guardrail. In this embodiment, to reduce the problem of snow and sand accumulation, a target air permeability is matched to the target flow field disturbance level.

[0035] Simulation technology was used to simulate the degree of flow field disturbance caused by the structural parameters of the original guardrail structure. Specifically, simulation analysis was performed on the parameters of the first tube type, the number of first crossbeams, and the spacing of the first posts. The degree of flow field disturbance caused by the structural parameters of each original guardrail structure was compared. By comparing and analyzing the flow field response of different original guardrail structures under the same flow conditions, the parameters that match the target air permeability were selected as the initial screening parameters. The initial screening parameters include the initial screening tube type parameters, the initial screening crossbeam number parameters, and the initial screening post spacing parameters. The guardrail structure that meets the initial screening parameters is selected as the initial screening guardrail structure.

[0036] The resulting initial screening guardrail structure can reduce the interference of the flow field on the environment and effectively reduce the amount of snow on the road surface in areas with windblown sand and snow, thereby ensuring traffic safety while promoting the economic efficiency and environmental friendliness of the project.

[0037] like Figure 2 As shown, Figure 2 This is the second experimental method for the beam-column type target guardrail structure in the implementation method. In a more specific implementation method, the degree of disturbance of the flow field by the structural parameters of the simulated original guardrail structure includes: Step 2.1: Use CFD simulation to simulate the degree of disturbance of the flow field by the structural parameters of the original guardrail structure.

[0038] CFD (Computational Fluid Dynamics) simulation technology is used to simulate the flow field disturbance in areas with blowing snow and blowing sand. CFD is a method that uses computers to perform numerical calculations and image display to analyze systems involving physical phenomena such as fluid flow and heat conduction. CFD flow field simulation is the process of simulating and analyzing fluid flow phenomena using CFD technology.

[0039] In the technical solution of this application, the degree of flow field disturbance corresponding to each first tube type parameter and the number of first crossbeams is screened through CFD simulation flow field simulation to obtain the initial tube type parameters and the initial crossbeam number parameters. This allows the air permeability of the initial screened guardrail structure to match the target air permeability, mitigating the problems of snow and sand accumulation on high-grade highways.

[0040] In step 3, the collision resistance performance of the structural parameters of the initial screening guardrail structure is simulated, and those that meet the target safety protection level are selected as the second screening guardrail structures.

[0041] In a specific example, we will take the target safety protection level as SA (level 5) as an example. The safety protection level SA refers to the SA (level 5) protection level requirement in the "Evaluation Standard for Safety Performance of Highway Guardrails" (JTG B05-01-2013).

[0042] According to the test conditions and evaluation methods for the SA level (level 5) protection level requirements in the "Evaluation Standard for Safety Performance of Highway Guardrails" (JTG B05-01-2013), a computer simulation collision test was conducted.

[0043] This method allows for the simulation of the initial safety protection level of the initial screening guardrail structure, comparison of the anti-collision performance of each initial screening guardrail structure, and thus the selection of the second screening guardrail structure that meets the target safety protection level.

[0044] In a specific example, the impact resistance performance of the structural parameters of the simulated initial screening guardrail structure includes: Step 2.2: Use finite element method (FEM) to simulate the collision performance of the initial screening guardrail structure's structural parameters.

[0045] A simulation of a car colliding with the guardrail can be performed using finite element modeling of the vehicle and the initial screening guardrail structure. The initial screening guardrail structure that meets the target safety protection level is then used as the second screening guardrail structure.

[0046] Of course, during the simulation process, those skilled in the art can also simulate the connection methods between the posts and beams, and the connection methods between the posts and the ground, by referring to the aforementioned scheme, thereby further improving the accuracy of the target guardrail structure. In other words, the guardrail parameters of this application also include other parts related to ventilation rate and safety protection level. The test process here can refer to the foregoing and will not be repeated here.

[0047] In step 4, the degree of disturbance of the flow field by the two-screen guardrail structure is verified by wind tunnel experiment; Following step 3, several secondary target guardrail structures matching the target permeability and target safety protection level were obtained. Wind tunnel experiments were then conducted on these secondary target guardrail structures. This allowed for the analysis of the low-disturbance ground-level airflow distribution under different flow field media such as wind, sand, or snow, ultimately yielding a three-screen guardrail structure whose actual permeability matched the target permeability.

[0048] Because snow particles have complex properties in reality, they are not only greatly affected by wind fields, but their viscosity is also difficult to analyze. Wind tunnel tests use scaled-down physical models to simulate the on-site environment, obtaining the motion trajectory and accumulation distribution of the simulated material under the combined action of various mechanical devices. This allows for more accurate selection of three-screen guardrail structures that match the actual air permeability with the target air permeability.

[0049] Step 5: The two-screen guardrail structure (i.e., the aforementioned three-screen guardrail structure) verified by the wind tunnel experiment is subjected to a real collision simulation experiment to obtain the target guardrail structure that meets the target safety protection level.

[0050] Finally, an actual safety protection level test was conducted on the three-screen guardrail structure, which was then used as the target guardrail structure.

[0051] In other embodiments, CFD simulation is used to simulate the degree of disturbance of the flow field by the structural parameters of the original guardrail structure. These structural parameters include the first tube shape parameters and the first number of crossbeams. Finite element method (FEM) simulation of collision experiments is used to simulate the collision resistance performance of the initial guardrail structure's structural parameters to obtain the first post spacing parameters.

[0052] In this embodiment, the initial screening parameters of the guardrail structure, including the initial screening tube type and the number of initial screening beams, are determined using CFD simulation of the flow field. The column spacing parameters are obtained through finite element method (FEM) collision simulation experiments. This is because the initial screening tube type and the number of initial screening beams significantly affect the air permeability of the guardrail structure, while the column spacing parameter is inversely proportional to the air permeability; that is, a larger column spacing results in better air permeability. Therefore, experiments can be conducted only on column spacing that matches the target safety protection level. This improves the efficiency of the experiment.

[0053] The structural parameters of the original guardrail structure include the first tubular parameters; The degree of disturbance of the flow field by the structural parameters of the original guardrail structure simulated by CFD simulation includes the first wind speed region index corresponding to the first tube type parameter, and the simulated amount of the first wind speed is less than or equal to the starting wind speed of the set material. The setting methods include: like Figure 3 As shown, Figure 3 This is the third experimental method for the beam-column type target guardrail structure in the implementation method. Step 2.11: Based on the negative correlation between the degree of disturbance of the flow field and the air permeability of the guardrail structure, the tube type parameters of the guardrail structure that meet the target flow field disturbance degree are selected as the initial screening parameters based on the negative correlation between the first wind speed area index and the air permeability.

[0054] The first wind speed zone index refers to the flow field distribution area with the first wind speed, including its length, width, and area.

[0055] By leveraging the inverse relationship between the first wind speed zone index and the air permeability, we can obtain the initial screening tube type parameters that meet the target air permeability.

[0056] Specifically, the simulation results of fluid dynamics experiments and the constructed mesh are combined into a single graph, and simulation experiments are conducted on various parameters of the first tube type.

[0057] At this point, in the flow field, different original pipe shapes can cause different degrees of disturbance to the flow field, and this degree of disturbance is characterized by wind speed.

[0058] like Figures 5-9 As shown, Figure 5 The first tube type parameter is an elliptical tube, and the dimensions of the elliptical tube are 120mm × 60mm; Figure 6 The first tube type parameter is a flat elliptical tube, and the dimensions of the flat elliptical tube are 100mm × 50mm; Figure 7 The first tube type parameter is a circular tube, and the dimensions of the circular tube are... =89mm; Figure 8 The first tube type parameter is a rectangular tube, and the dimensions of the rectangular tube are 100mm × 50mm; Figure 9 The first tube type parameter is a square tube, and the dimensions of the square tube are 75mm × 75mm.

[0059] Figures 5 to 9 In the diagram, blue to red indicates wind speed increasing from low to high.

[0060] During the experiment, as long as the starting wind speed of the material in the area where the wind blows snow or sand is determined, the first wind speed area index can be calculated accordingly.

[0061] With the initial wind speed of the material being 4 m / s, the first wind speed region index corresponding to each first tube type parameter is obtained as shown in the table below. The first wind speed region is the low speed region in the table below, which is the dark blue region in the figure.

[0062]

[0063] Ranking the impact of different tube types on the flow field disturbance index, the elliptical tube (120mm×60mm) has the least impact on the flow field disturbance, with a low-velocity area of ​​only 2611mm2. The flat elliptical tube (100mm×50mm) is the next most affected, with a low-velocity area of ​​4462mm2. The rectangular tube (50mm×100mm) has the greatest impact on the flow field disturbance, with a low-velocity area of ​​64433mm2, which is 24.68 times that of the elliptical tube (120mm×60mm) and 14.44 times that of the flat elliptical tube (100mm×50mm).

[0064] It is evident that the first wind speed region index is smaller for both streamlined tube types: the elliptical tube (120mm×60mm) and the flat elliptical tube (100mm×50mm). These two tube types can achieve the maximum possible air permeability.

[0065] In the foregoing embodiments, the structural parameters of the original guardrail structure include the first crossbeam quantity parameter. The degree of disturbance of the flow field by the structural parameters of the original guardrail structure to the flow field by CFD simulation includes the second wind speed region index corresponding to the first crossbeam quantity parameter. The simulated amount of the second wind speed is greater than the starting wind speed of the set substance and the overlap index between the second wind speed region index and the set road surface index. Please continue to refer to Figure 3 The setting methods include: Step 2.12: Based on the positive correlation between the overlap index and the air permeability, select those that meet the target flow field disturbance level as the initial screening parameter for the number of beams of the guardrail structure.

[0066] In this plan, a road surface model needs to be established, which is modeled with reference to the road structure of the target area.

[0067] The second region differs from the first region in that the simulated value of the first wind speed in the first region is less than or equal to the starting wind speed of the set substance, while the simulated value of the second wind speed in the second region needs to be greater than the starting wind speed of the set substance.

[0068] In the simulation results, the number of initial screening beams is determined by the area where the second wind speed region index overlaps with the horizontal projection of the road surface. The smaller the overlapping area, the better the air permeability of the target guardrail structure, allowing snow, sand, and other materials to be blown away from the road surface, thus reducing snow and sand accumulation.

[0069] The number of initial screening beams that meet the target permeability can be obtained by positively correlating the value of the overlapping area between the second wind speed zone index and the horizontal projection of the road surface with a set width with the permeability.

[0070] In such Figures 10-11 In the technical solution, Figure 10 This is a simulation example of three crossbeams in an elliptical tube (120mm × 60mm). Figure 11 This is a simulation example of four crossbeams in an elliptical tube (120mm × 60mm). Similarly, the wind speed increases from blue to red.

[0071] according to Figure 10 and Figure 11 It can be seen that the target guardrail structure with three horizontal beams has a large area overlapping with the second wind speed zone index within the horizontal projection range of the road surface (i.e., the area not in dark blue in the figure). As a result, sand and snow can pass through the initial screening guardrail structure and leave the road surface with almost no accumulation.

[0072] In the aforementioned embodiments, the target air permeability can be greater than or equal to 85%. Within this range, sand and snow can be blown away from the road surface, reducing the amount of sand and snow on the road surface.

[0073] In the foregoing embodiments, the wind tunnel experiment includes at least one of an empty wind tunnel experiment and a medium accumulation comparison experiment. The empty wind tunnel experiment only simulates the flow field and does not simulate the materials (sand, snow) in the flow field. The medium accumulation comparison experiment simulates both the flow field and the materials in the flow field in the wind tunnel. One or both experimental methods can be used. This allows for obtaining the degree of matching between the actual permeability and the target permeability of the two-screen guardrail structure through wind tunnel experiments, thereby further screening the three-screen guardrail structure and ensuring that the target guardrail structure meets the target permeability under actual conditions.

[0074] like Figure 4 As shown, Figure 4 This is the fourth experimental method for the beam-column type target guardrail structure in the embodiments. In the aforementioned embodiments, the method further includes the following between step 3 and step 4: Step 3.1: Calculate the air permeability of the two-screen guardrail structure as the air permeability to be verified; Step 3.2: Compare the air permeability to be verified with the target air permeability. If they match, proceed to step 4. If they do not match, repeat steps 1 to 3.

[0075] This allows for the verification of the air permeability of the two-screen guardrail structure. If the structure meets the requirements, proceed to step 4; otherwise, repeat steps 1 to 3. This enables further verification of the air permeability of the two-screen guardrail structure before actual testing.

[0076] like Figures 12 to 17 , Figure 12 This is a structural schematic diagram of the guardrail structure in an embodiment of the present invention; Figure 13 yes Figure 12 A top view of a partial structure; Figure 14 yes Figure 13 A magnified schematic diagram of a local structure; Figure 15 yes Figure 12 One of the side views; Figure 16 yes Figure 15 A magnified schematic diagram of a local structure; Figure 17 yes Figure 12 The second side view.

[0077] In another aspect of this application, a target guardrail structure is provided, the protection level of which is SA. The target guardrail structure has a length direction extending in the same direction as the crossbeam, that is, the extension direction of the target guardrail structure, and also has a thickness direction perpendicular to the length direction and a height direction perpendicular to the length direction and the thickness direction, that is, vertical.

[0078] The target guardrail structure includes several horizontal beams arranged vertically in sequence and columns 1 for supporting the horizontal beams. The cross-section of the horizontal beams is flat ellipse and the horizontal beams have narrow sides. The narrow sides of the horizontal beams are opposite to and fixedly connected to the columns along the thickness direction of the target guardrail structure.

[0079] The crossbeams extend horizontally and are spaced out vertically. A portion of the column 1 is fixed to the ground, while another portion protrudes above the ground and is fixedly connected to several crossbeams. The column 1 and the crossbeams can be connected by welding, by using anti-blocking blocks 4, or by other connection methods, which can be chosen by those skilled in the art.

[0080] By adopting the method described in this application, the structure of flat elliptical columns 1 and beams can achieve a safety protection level of SA for the target guardrail structure, while also improving the ventilation rate of the target guardrail structure.

[0081] As an alternative example, both the cross-section of the beam and column 1 are planar elliptical, with the narrow side of the beam facing and fixedly connected to the narrow side of column 1. The horizontal cross-section of column 1 is planar elliptical, and the vertical cross-section of the beam is also planar elliptical; both have the same cross-sectional shape. The "planar elliptical" shape is racetrack-shaped, with two opposing straight walls as long sides. At each end of the two long sides are two arc-shaped narrow sides, located on the same circumference. Both the beam and column 1 include connected arc-shaped narrow sides and straight long sides. The long sides of the beam face each other vertically, while the narrow sides face each other along their thickness. The long sides of column 1 face each other along the extension direction of the beam.

[0082] The narrow sides of the crossbeam are opposite each other along the thickness direction, and the narrow sides of the column 1 are also opposite each other along the thickness direction. The narrow sides of the column 1 and the narrow sides of the crossbeam are opposite each other along the thickness direction and are fixedly connected.

[0083] Specifically, the narrow side of the beam is the first narrow side 51b, the long side of the beam is the first long side 51a, the narrow side of the column 1 is the second narrow side 52b, and the long side of the column 1 is the second long side 52a.

[0084] Combination Figure 14 , Figure 16 The content shown is as follows. Figure 14 This is a top view of the target guardrail structure. Figure 16 This is a side view of the target guardrail structure. Figure 14 The thickness of the guardrail structure in the middle is along the top and bottom of the paper. Figure 16 The thickness direction of the guardrail structure in the middle is the left-right direction of the paper.

[0085] exist Figure 14 The end face of column 1 is shown in the figure. Figure 14 In the figure, the column 1 has two second narrow sides 52b opposite each other along the thickness direction. The top surface of the beam is the first long side 51a, and a portion of the first narrow side 51b is shown where it meets the first long side 51a.

[0086] like Figure 16 The content shown, Figure 16 The end face of the beam is shown, which fully demonstrates the cross-sectional shape of the beam. Figure 16 In the crossbeam, the two first long sides 51a are vertically opposite each other, and the two first narrow sides 51b are horizontally opposite each other in the thickness direction. Conversely, only one side of the column 1, the second long side 52a, and the portion of the second narrow side 52b connected to the second long side 52a are shown. The second narrow side 52b is opposite to the first narrow side 51b in the thickness direction.

[0087] Therefore, the dimension occupied in the thickness direction of the target guardrail structure ensures the safety protection level of the target guardrail structure.

[0088] In this embodiment, the cross-sectional dimensions of the beam and the column 1 are identical. That is, the cross-section of the beam and the cross-section of the column 1 can overlap. The beam and the column 1 are formed as a single tubular component, which is then cut to different lengths to form the beam and column 1 respectively. This achieves a "strong beam, weak column" effect, improving the impact resistance of the target guardrail structure. Of course, the cross-sectional dimensions of the beam and the column 1 can also be different. Those skilled in the art can choose according to their needs to achieve the "strong beam, weak column" effect.

[0089] In some specific implementations, the number of crossbeams is three, but it can also be more or fewer, depending on the need to increase ventilation and ensure a safety protection level of SA.

[0090] In the technical solution of this application, a first reference plane with a height of 1m and extending vertically is defined. The area of ​​the projected region formed by projecting the crossbeam and column 1 onto the first reference plane in the horizontal direction is the blocking area, and the ratio of the blocking area to the first reference plane is less than or equal to 30%. Within this range, its ventilation rate is significantly increased compared with traditional target guardrail structures.

[0091] Furthermore, the ratio of the blocking area to the first reference surface is less than or equal to 15%. Within this range, the target guardrail structure can further prevent snow and sand accumulation on the road surface.

[0092] In such Figure 12 In the example shown, the beams include a first beam 21, a second beam 22, and a third beam 23, which are arranged alternately from bottom to top. The distances from the ground to the first beam 21 are h1, to the second beam 22 h2, and to the third beam 23 h3, respectively, where 35cm ≤ h1 ≤ 60cm, 80cm ≤ h2 ≤ 100cm, and 110cm ≤ h3 ≤ 130cm. The height of each beam from the ground is the distance from its vertical midpoint to the ground.

[0093] The height of the three crossbeams from the ground can also be used as structural parameters of the original guardrail structure. After simulation, the actual verification is carried out through wind tunnel experiments, which will not be elaborated here.

[0094] Within this range, the ventilation rate of the target guardrail structure can be further increased. Optionally, h1 is 45cm, h2 is 90cm, and h3 is 120cm. Within the above range, the ratio of the blocking area to the first reference surface can be guaranteed to be less than or equal to 15%.

[0095] In other embodiments, as an example, the columns 1 are spaced apart by a distance s1 along the extension direction of the beam, where 1.5m ≤ s1 ≤ 3m; or, the height of the top of the column 1 from the ground is h4, where 119cm ≤ h4 ≤ 139cm. In another example, adjacent columns 1 are spaced apart by a distance s1 along the extension direction of the beam, where 1.5m ≤ s1 ≤ 3m, and the height of the top of the column 1 from the ground is h4, where 119cm ≤ h4 ≤ 139cm. Optionally, h4 is 129cm. This ensures both the protection level and the ventilation rate of the target fence structure.

[0096] In the above embodiment, the post 1 also includes a pile segment 11 for burying in the ground, the vertical dimension of the pile segment 11 being greater than or equal to 120cm. This improves the impact resistance of the target guardrail structure.

[0097] The dimensions of pile segment 11 are also part of the guardrail parameters, and those skilled in the art can conduct tests by referring to the aforementioned test methods.

[0098] like Figure 13 As shown, to achieve the connection of the crossbeam, the target guardrail structure also includes a connecting sleeve 3 that can be built into two adjacent beam segments 24 of the crossbeam. The connecting sleeve 3 fits against the inner wall of the crossbeam. Several screw holes are opened on the connecting sleeve 3, and screw holes are also opened on the end of the crossbeam that is adapted to the connecting sleeve 3. The connecting sleeve 3 is threadedly connected to the crossbeam.

[0099] The cross-sectional shape of the connecting sleeve 3 matches the internal shape of the beam. Each beam consists of several beam segments 24 connected sequentially. Part of the connecting sleeve 3 is embedded in one of two adjacent beam segments 24, and part is embedded in the other of two adjacent beam segments 24. Then, the connecting sleeve 3 is threadedly connected to the corresponding beam segment 24.

[0100] In the aforementioned embodiment, the thickness of the plate material of at least one of the beams and posts 1 is greater than or equal to 6 mm. This improves the impact resistance of the target guardrail structure.

[0101] Optionally, the average tensile strength of at least one of the connecting sleeve 3, the crossbeam, and the post 1 is greater than or equal to 355 MPa. The target guardrail structure uses high-strength steel with high tensile strength, with a steel consumption of only 52.6 kg / m, which is about 22% lower than the 65.7 kg / m steel consumption of the target guardrail structure with a safety protection level of SA on the market. This reduces the amount of steel used in the guardrail production process, achieving the effect of less steel consumption, better performance indicators, and stronger protection level.

[0102] Disturbance of windblown sand (snow) flow is key to the formation of road surface sand (snow), and guardrails operate in the ground-level air layer. Therefore, the design of a target guardrail structure with low disturbance to the ground-level air flow field is particularly crucial. When the air permeability below 1m exceeds 85%, snow resistance is significantly reduced. By adopting the technical solution of this application, the air permeability of the target guardrail structure below 1m reaches 88%, which means the ratio of the blocking area to the first reference surface is 12%. Simulation and wind tunnel experiments demonstrate that this target guardrail structure can mitigate the disasters of sand and snow accumulation on highways in special road areas.

[0103] In the aforementioned embodiments, the target guardrail structure further includes a buffer block 4, which has a first connecting section 41 for fixed connection with the post 1 and a second connecting section 42 for fixed connection with the crossbeam. The first connecting section 41 and the second connecting section 42 are spaced apart to form a buffer section. The first connecting section 41, the second connecting section 42, and the buffer section are distributed along the thickness direction of the target guardrail structure, with the buffer section located between the first connecting section 41 and the second connecting section 42. The buffer block, with its buffer section, can prevent the post 1 from deforming after the target guardrail structure is impacted.

[0104] The first connecting section 41 has a first receiving groove for embedding the post 1, and the second connecting section 42 has a second receiving groove for embedding the crossbeam. The first receiving groove passes vertically through the anti-blocking block 4, and the second receiving groove passes horizontally through the anti-blocking block 4. The target guardrail structure also includes connecting bolts, which pass through the post 1 and the first receiving groove in sequence to connect the post 1 to the first receiving groove. The connecting bolts also pass through the crossbeam and the second receiving groove in sequence to connect the crossbeam to the second receiving groove.

[0105] In other embodiments, the guardrail structure further includes a post cap structure disposed at the top of the post, the post cap structure being connected to a wind power generation device. The wind power generation device is used to power the early warning device. The post cap structure has a base that is fixedly connected to the top of the post 1. Thus, when the wind force exceeds a set threshold, the wind power generation device starts to operate and power the early warning device.

[0106] In other embodiments, the guardrail structure is further provided with post-type delineators 6, which are installed on the posts 1. The delineators 6 have a trapezoidal cross-sectional shape. When the main line travels in the left direction, the delineators 6 are yellow; when the main line travels in the right direction, the delineators 6 are white. The reflective surface is made of a high-transmittance material.

[0107] In some other embodiments, an anti-glare plate 7 is also provided at the top of the column 1. The anti-glare plate 7 is made of basalt fiber and is integrally molded from basalt material. It includes the anti-glare plate 7 body and the base. The base is provided with base connection holes for fixing the basalt anti-glare plate 7.

[0108] In some embodiments, a vibration cable is also provided on the second crossbeam 22, and the vibration cable is equipped with tension sensors arranged at intervals. The tension sensors are connected to the alarm signal. The distance between two adjacent tension sensors is between 45m and 70m (including the endpoint value). Thus, an alarm can be triggered after deformation of the guardrail structure is detected.

[0109] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An experimental method for beam-column type target guardrail structures, characterized in that, The experimental methods include: Step 1: Obtain several original guardrail structures; Step 2: Simulate the degree of disturbance of the flow field by the structural parameters of the original guardrail structure, and select the initial guardrail structure based on the set method; Step 3: Simulate the anti-collision performance of the initial screening guardrail structure and select those that meet the target safety protection level as the second screening guardrail structure; Step 4: Verify the degree of disturbance of the flow field by the two-screen guardrail structure through wind tunnel experiments; Step 5: Using a real collision simulation experiment, the two-screen guardrail structure verified by the wind tunnel experiment is used to obtain the target guardrail structure that meets the target safety protection level.

2. The experimental method for the target guardrail structure according to claim 1, characterized in that, The degree of disturbance to the flow field caused by the structural parameters of the simulated original guardrail structure includes: Step 2.1: Use CFD simulation to simulate the degree of disturbance of the flow field by the structural parameters of the original guardrail structure.

3. The experimental method for the target guardrail structure according to claim 2, characterized in that, The structural parameters of the original guardrail structure include the first tubular parameters; The degree of disturbance to the flow field by the structural parameters of the original guardrail structure, simulated using CFD flow field simulation, includes: The first wind speed area index corresponding to the first tube type parameter, the simulated value of the first wind speed is less than or equal to the starting wind speed of the set substance. The setting methods include: Step 2.11: Based on the negative correlation between the degree of disturbance of the flow field and the air permeability, the pipe type parameters of the guardrail structure that meet the target degree of flow field disturbance are selected as the initial screening parameters.

4. The experimental method for the target guardrail structure according to claim 3, characterized in that, The structural parameters of the original guardrail structure include the number of first crossbeams; The degree of disturbance to the flow field by the structural parameters of the original guardrail structure, simulated using CFD flow field simulation, includes: The second wind speed zone index corresponding to the first crossbeam quantity parameter, the simulated amount of the second wind speed is greater than the starting wind speed of the set material, and the overlap index between the second wind speed zone index and the set road surface index. The setting methods include: Step 2.12: Based on the positive correlation between the overlap index and the air permeability, select those that meet the target flow field disturbance level and use them as the initial screening parameter for the number of beams of the guardrail structure.

5. The experimental method for the target guardrail structure according to claim 1, characterized in that, The anti-collision performance of the structural parameters of the simulated primary screening guardrail structure includes: Step 2.2: Use finite element method (FEM) to simulate the collision performance of the initial screening guardrail structure's structural parameters.

6. The experimental method for the target guardrail structure according to any one of claims 1-5, characterized in that, The wind tunnel experiment includes at least one of the following: an empty wind tunnel experiment and a medium accumulation comparison experiment.

7. The experimental method for the target guardrail structure according to any one of claims 1-5, characterized in that, The target's security protection level is SA.

8. The experimental method for the target guardrail structure according to any one of claims 1-5, characterized in that, The tubular parameters of the target guardrail structure are flat ellipse.

9. The experimental method for the target guardrail structure according to any one of claims 1-5, characterized in that, The target guardrail structure has 3 horizontal beams and 3m vertical posts.

10. A beam-column type target guardrail structure, characterized in that, It includes several horizontal beams arranged vertically in sequence and columns for supporting the horizontal beams. The cross-section of each horizontal beam is a flat ellipse. Each horizontal beam includes a narrow side portion. The narrow side portion of the horizontal beam and the column are opposite to and fixedly connected to each other along the thickness direction of the target guardrail structure.

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