Rockfall pre-perception active avoidance type steel column support system

Abstract

The present application relates to the technical field of slope rockfall protection, and provides a rockfall pre-perception active avoidance type steel column support system, which comprises a rotatable column foot, a deflection steel column, a pulley node, a pre-perception upward pulling anchor rope and a connecting piece. The bottom ear plate of the deflection steel column is provided with an opening, and the fitting tolerance between the opening and the diameter of the pin shaft is relatively large, so that the steel column can be conveniently rotated in the horizontal direction; the pulley node is provided with double pulleys, and each of the two pulleys is wound with a pre-perception upward pulling anchor rope; the two anchor points of each rope are distributed on the two sides of the projection line of the initial axis of the steel column on the slope surface (hereinafter referred to as the projection line), one of the anchor points is near the projection line, and the other anchor point is away from the projection line. Before the rockfall impacts the steel column, the rockfall will first impact the anchor rope on one side near the projection line, and under the combined action of the anchor rope, the steel column will deflect to the other side, so that the rockfall impact can be avoided or the impact damage can be reduced. The present application solves the protection problem of the rockfall directly impacting the steel column, and greatly improves the impact resistance reliability and disaster prevention toughness of the passive net.

Description

Technical Field

[0001] This invention relates to the field of slope rockfall protection technology, and provides a rockfall pre-sensing active avoidance steel column support system, which is applicable to the steel column collision prevention problem of passive flexible protection net system, and can significantly improve the impact resistance reliability and disaster prevention resilience of passive net. Background Technology

[0002] Landslides and rockfalls are common geological disasters in mountainous areas of my country. Due to their suddenness, randomness, and severity, they pose a significant safety hazard to people's lives and property. In my country, flexible protective structures are crucial technical equipment for preventing and mitigating losses from landslides and rockfalls. Passive flexible protective netting systems, as an important branch of flexible netting systems, can effectively intercept falling rocks, reducing their impact on people's lives and property and the normal operation of roads.

[0003] However, the following problems still exist:

[0004] When designing passive flexible protective nets, the scenario of falling rocks directly impacting steel columns is generally not taken into consideration. However, this situation poses a potential risk. When falling rocks directly impact steel columns, they can easily cause severe deformation, twisting, or direct damage, affecting the load-bearing capacity of the entire structure and significantly reducing the protective height, thereby decreasing the reliability of the passive net system. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a rockfall pre-sensing active avoidance steel column support system, which is suitable for solving the steel column collision prevention problem of passive flexible protective net systems and can overcome the deficiencies of current technologies.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The rockfall pre-sensing active avoidance steel column support system includes: a rotatable column base, a swaying steel column, a pulley node, a pre-sensing upper anchor rope, and connectors;

[0008] The base plate of the rotatable column foot is welded with a Y-shaped lug plate. The Y-shaped lug plate has a round hole and a pin. Two limiting springs are fitted on the pin to center the lug plate at the base of the column. The rotatable column foot allows the steel column to rotate in the horizontal direction as well.

[0009] The base of the swaying steel column is welded with a base ear plate. The inner wall of the opening of the base ear plate is a circular surface tangent to the surface of the ear plate. The diameter of the opening and the diameter of the pin are relatively large, and the clearance is large, which facilitates the horizontal rotation of the steel column. The top of the column is welded with a top plate and a top ear plate.

[0010] The pulley node is equipped with double pulleys, and the pulley support frame is connected to the column top ear plate via eye bolts and shackles. Each pulley has a pre-sensing upward anchor rope wound around it. The two anchor points of each rope are located on the uphill side, distributed on both sides of the projection line of the swaying steel column axis onto the slope (hereinafter referred to as the projection line). One anchor point is near the projection line, and the other is far from it. A pressure-reducing ring is generally attached to the pre-sensing upward anchor rope.

[0011] Preferably, the difference Δd between the minimum inner diameter of the hole in the column base lug plate and the outer diameter of the pin should be determined by the following formula:

[0012] Δd=λD

[0013] In the formula, D is the outer diameter of the pin, and λ can be taken as 0.1 to 0.125.

[0014] Preferably, the axial length l of the single-sided limiting spring s The following requirements should be met:

[0015] l s ≥d h tan15°

[0016] In the formula d h The edge distance of the hole for the Y-shaped ear plate.

[0017] Preferably, the anchor point spacing of the pre-sensing pull-up anchor rope should meet the following requirements:

[0018] d a1 =Min(αL,1)

[0019]

[0020] In the formula d a1 d is the distance between two anchor points close to the projection line. a2 The distance between two anchor points far from the projection line is in meters; Min is a function that takes the smaller of the two values, where α can be 1 / 8 to 1 / 6, and L is the length of the column. c The column spacing in a passive flexible protection system.

[0021] Preferably, the distance d from the center of the pin shaft is the midpoint of the line connecting the two anchor points close to the projection line. w The following requirements should be met:

[0022] d w ≥Max(L,2vt)

[0023] In the formula, Max is a function that takes the larger of the two values, v is the maximum impact velocity that falling rocks may reach during the protection design, and t is the deflection reaction time of the steel column, which is taken as 0.08s.

[0024] Preferably, the surface of the double pulley disc after installation is parallel to the plane where the pre-sensing upper anchor rope is located, and the pulley shaft is perpendicular to the plane where the pre-sensing upper anchor rope is located; the diameter of the pulley groove is not less than 8 times the diameter of the steel wire rope used for the pre-sensing upper anchor rope.

[0025] The yaw trajectory of the column top node is controllable and can be determined as follows: Assume an Oxyz right-handed rectangular coordinate system, with the x-axis passing through four anchor points. The midpoint of the line connecting two anchor points closest to the projection line is the origin O. The initial axis of the steel column lies in the yz plane. Then, the yaw trajectory of the column top node can be determined by the following formula:

[0026]

[0027]

[0028] In the formula, y0 and z0 are the y and z coordinates of the pin center, which are known quantities after the system configuration is determined. L a 'b' is the length of a single pre-sensing pull-up anchor rope, which is the sum of the distances from the two anchor points of the rope to the center of the pulley shaft. It is a known quantity, and 'b' is an intermediate variable.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] When a rockfall is likely to impact a steel column, it will first strike the pre-sensing upper anchor rope near the projection line above the column. Since the probability of a perfectly symmetrical impact is zero, the center of gravity of the rockfall will always be closer to the upper anchor rope near a certain projection line. After the rockfall hits, the tension on that anchor rope increases dramatically. Due to the special way the anchor rope is threaded and the way the anchor points are arranged, the steel column will actively sway to the other side under the combined force of this anchor rope, thereby avoiding the impact of the rockfall. Depending on the shape, speed, and impact location of the rockfall, the impact damage to the steel column can be reduced or completely avoided, thus greatly improving the survivability of the steel column in the field and enhancing the reliability and disaster resilience of the passive net system against rockfall impacts. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the rockfall pre-sensing active avoidance steel column support system in the embodiment.

[0032] Figure 2 This is an isometric view of the deflection of the rockfall pre-sensing active avoidance steel column support system in the embodiment.

[0033] Figure 3 This is a top view illustrating the deflection of the rockfall pre-sensing active avoidance steel column support system in the embodiment.

[0034] Figure 4 This is an isometric view of the rotatable column base in the embodiment;

[0035] Figure 5 This is a schematic diagram showing the connection between the rotatable column base and the eccentric steel column base in the embodiment;

[0036] Figure 6 This is an isometric schematic diagram of the skewed steel column in the embodiment;

[0037] Figure 7 This is an isometric schematic diagram of the pulley node in the embodiment;

[0038] Figure 8 This is an isometric schematic diagram of the pre-sensing pull-up anchor rope and connector in the embodiment;

[0039] Figure 9 This is a schematic diagram showing the connection between the pulley node and the eccentric steel column head in the embodiment.

[0040] Figure 10 This is a top view of the dynamic simulation results of the impact of spherical falling rocks in the experimental example.

[0041] Figure 11 This is a top view of the dynamic simulation results of the implementation effect of the hexahedral rockfall impact in the experimental example.

[0042] In the diagram: 1-Rotable column foot, 2-Oscillating steel column, 3-Pulley node, 4-Sensing pull-up anchor rope, 11-Base plate, 12-Y-shaped ear plate, 13-Pin shaft, 14-Limiting spring, 21-Column base ear plate, 22-Column body, 23-Column top plate, 24-Column top ear plate, 31-Pulley, 32-Pulley support frame, 33-Pulley shaft, 34-Lifting eye bolt, 35-Shackle, 42-Wire rope, 42-Pressure relief ring, 51-Through shackle, 52-Figure-eight rope. Detailed Implementation

[0043] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0044] Example

[0045] like Figure 1-3 As shown, a rockfall pre-sensing active avoidance steel column support system includes: a rotatable column base 1, a swaying steel column 2, a pulley node 3, and a pre-sensing upward anchor rope 4.

[0046] like Figure 4-5 As shown, a Y-shaped lug 12 is welded to the base plate 11 of the rotatable column foot 1. A round hole is opened on the Y-shaped lug 12 and a pin 13 passes through it. Two limiting springs 14 are sleeved on the pin 13 to center the column base lug 21. The rotatable column foot 1 enables the steel column to have a certain rotation ability in the horizontal direction.

[0047] For example Figure 6As shown, the base of the swaying steel column 2 is welded with a column base ear plate 21. The inner wall of the opening of the column base ear plate 21 is a circular annular surface tangent to the surface of the ear plate. The diameter of the opening is relatively large compared with the diameter of the pin 13 and the fitting clearance is large, which facilitates the horizontal rotation of the steel column. The top of the column body 22 is welded with a column top plate 23 and a column top ear plate 24.

[0048] For example Figure 7 As shown, pulley node 3 is equipped with double pulleys 31. The two pulleys 31 are mounted on pulley support frame 32 via pulley shaft 33. The pulley support frame 32 is connected to the column top ear plate 24 via eye bolts 34 and shackles 35. Each of the two pulleys 31 is wound with a pre-sensing upward anchor rope 4. The two anchor points of each upward anchor rope are located on the uphill side and are distributed on both sides of the projection line (hereinafter referred to as the projection line) of the axis of the swaying steel column 2 on the slope surface. One anchor point is near the projection line, and the other anchor point is far away from the projection line. The pre-sensing upward anchor rope 4 is generally connected with a pressure relief ring 42.

[0049] like Figure 8 As shown, the pre-sensing pull-up anchor rope 4 includes a steel wire rope 41, a pressure relief ring 42 installed on the steel wire rope 41, a figure-eight rope 52 connected to the end of the steel wire rope 41, and a shackle 51 installed on the figure-eight rope 52.

[0050] Preferably, the difference Δd between the minimum inner diameter of the opening in the base lug 21 and the outer diameter of the pin 13 should be determined by the following formula:

[0051] Δd=λD

[0052] In the formula, D is the outer diameter of the pin 13, and λ can be taken as 0.1 to 0.125. If the diameter of the pin 13 is 40mm (determined according to the bearing capacity), then the minimum inner diameter of the opening of the column base ear plate 21 can be taken as 45mm. The fit tolerance satisfies the above formula to ensure that the horizontal sway of the steel column is not obstructed.

[0053] Preferably, the axial length l of the single-sided limiting spring 14 is... s The following requirements should be met:

[0054] l s ≥d h tan15°

[0055] In the formula d h The hole edge distance of the Y-shaped ear plate 12 is 100mm (determined according to the bearing capacity). Then the axial length of the single-sided limiting spring 14 is not less than 27mm, which can be 40mm. This ensures that the horizontal sway of the steel column is not obstructed while keeping the bottom ear plate 21 of the column in the center.

[0056] Preferably, the anchor point spacing of the pre-sensing pull-up anchor rope 4 should meet the following requirements:

[0057] d a1 =Min(αL,1)

[0058]

[0059] In the formula d a1 d is the distance between two anchor points close to the projection line. a2 The distance between two anchor points far from the projection line is in meters; Min is a function that takes the smaller of the two values, where α can be 1 / 8 to 1 / 6, and L is the length of the column 22. c This refers to the column spacing in a passive flexible protection system. If the steel column length L = 4m (determined based on the required protection height), the column spacing L... c =10m (a commonly used value in the industry), if we take α = 1 / 6.6, then we can take d. a1 =0.6m, d a2 =8m, which satisfies the requirements of the above formula.

[0060] Preferably, the distance d from the center of pin 13 is the midpoint of the line connecting the two anchor points close to the projection line. w The following requirements should be met:

[0061] d w ≥Max(L,2vt)

[0062] In the formula, Max is a function that takes the larger of the two values, v is the maximum impact velocity that falling rocks may reach during the protection design, and t is the deflection reaction time of the steel column, which is taken as 0.08s. This formula is to meet the reaction time of the steel column deflection. In the industry, v is usually taken as 25m / s, so d can be taken as... w =4m.

[0063] like Figure 9 As shown, preferably, the surface of the double pulley 31 after installation is parallel to the plane where the pre-sensing upper anchor rope 4 is located, and the pulley shaft 33 is perpendicular to the plane where the pre-sensing upper anchor rope 4 is located; the diameter of the groove of the pulley 31 is not less than 8 times the diameter of the steel wire rope 41 used for the pre-sensing upper anchor rope 4. If the diameter of the anchor rope is 20mm, the diameter of the groove of the pulley 31 can be 160mm. The pulley 31 of the appropriate specification is selected according to this value.

[0064] The yaw trajectory of the column top node is controllable and can be determined as follows: Assume an Oxyz right-handed rectangular coordinate system, with the x-axis passing through four anchor points. The midpoint of the line connecting two anchor points closest to the projection line is the origin O. The initial axis of the steel column lies in the yz plane. Then, the yaw trajectory of the column top node can be determined by the following formula:

[0065]

[0066]

[0067] In the formula, y0 and z0 are the y and z coordinates of the center of pin 13, which are known quantities after the system configuration is determined.a 'b' is the length of a single pre-sensing pull-up anchor rope 4, which is the sum of the distances from the two anchor points of the rope to the center of the pulley shaft 33. It is a known quantity, and 'b' is an intermediate variable.

[0068] Test case

[0069] To better demonstrate the implementation effect of this invention, a finite element dynamic simulation model was established based on the LS-DYNA explicit dynamic simulation platform. The relevant parameters are as follows: steel column length L = 4m, and the distance d between the two anchor points close to the projection line. a1 =0.6m, the distance d between two anchor points far from the projection line a2 =8m, the distance d from the midpoint of the line connecting the two anchor points closest to the projection line to the column base. w =4m, the steel column axis is set horizontally, the steel column section is P219×8 round pipe, and the diameter of the anchor rope is 20mm;

[0070] The pulley node is simulated using a special sliding node, which can achieve an equivalent inner boundary effect to the pulley. The anchor point and column base node are in the same vertical plane, and the column base is set as a hinge. The impact energy is 800kJ, the impact velocity is 25m / s, and the impact is vertically downward. The mass of the falling rocks is 2500kg. There are two working conditions: the falling rocks are spherical and cubic. The diameter of the sphere is 1.25m, and the side length of the cube is 1m. Figure 10 , Figure 11 As shown;

[0071] In the spherical impact test, the horizontal projection point of the sphere's center of gravity is 0.1m to the right of the steel column axis, which is very close to the axis of symmetry. In the cubic impact test, the horizontal projection point of the block's center of gravity is 0.3m to the right of the steel column axis, which is a test with slightly greater asymmetry.

[0072] Simulation results show that although the falling rock still collides with the steel column under the spherical impact condition, the steel column buckling damage is low and it does not fail (unlike traditional steel column support systems which are considered to be damaged in this case), because the steel column has already moved away from the impact point. It still has a certain load-bearing capacity. Figure 10 );

[0073] In cubic impact conditions, the steel column can completely avoid collisions with falling rocks, achieving a very good protective effect. Figure 11 The above dynamic simulation process shows that the rockfall pre-sensing active avoidance steel column support system has a good steel column protection effect.

[0074] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A rockfall pre-sensing active avoidance steel column support system, comprising a rotatable column base (1), a swaying steel column (2), a pulley node (3), a pre-sensing upward anchor rope (4), and a connector (5), wherein the rotatable column base (1) and the bottom end of the swaying steel column (2) are hinged, the pulley node (3) is installed on the top of the swaying steel column (2), and the pre-sensing upward anchor rope (4) is fitted onto the pulley node (3), with both ends of the pre-sensing upward anchor rope (4) respectively fixed to anchor points, characterized in that: A Y-shaped lug (12) is welded to the base plate (11) of the rotatable column foot (1), and a round hole is opened on the Y-shaped lug (12) and a pin (13) is inserted through it; a column base lug (21) is welded to the column foot end of the sway steel column (2), and the column base lug (21) is fitted on the pin (13), and a limiting spring (14) for centering the column base lug (21) is fitted on the pin (13); The top of the column body (22) of the swaying steel column (2) is welded with a column top plate (23) and a column top ear plate (24), and the pulley node (3) is installed on the column top ear plate (24); The pulley node (3) includes a pulley support frame (32), a pulley shaft (33) and two pulleys (31). The two pulleys (31) are mounted on the pulley support frame (32) through the pulley shaft (33). The pulley support frame (32) is connected to the column top ear plate (24) through eye bolts (34) and shackles (35). Each of the two pulleys (31) is wound with a pre-sensing pull-up anchor rope (4). The two anchor points of each pre-sensing pull-up anchor rope (4) are located on the uphill side and distributed on both sides of the projection line of the axis of the swaying steel column (2) on the slope. One anchor point is near the projection line and the other anchor point is far away from the projection line.

2. The rockfall pre-sensing active avoidance steel column support system according to claim 1, characterized in that: The base lug plate (21) has a through hole, and the wall of the through hole is an annular surface tangent to the surface of the base lug plate (21). The difference Δd between the minimum inner diameter of the base lug plate (21) and the outer diameter of the pin (13) is as follows: Δd=λD In the formula, D is the outer diameter of the pin (13), and λ can be taken as 0.1 to 0.

125.

3. The rockfall pre-sensing active avoidance steel column support system according to claim 1, characterized in that: The axial length l of the limiting spring (14) s The following requirements must be met: L s ≥d h tan15° In the formula, d h The edge distance of the hole for the Y-shaped ear plate (12).

4. The rockfall pre-sensing active avoidance steel column support system according to claim 1, characterized in that: The pre-sensing pull-up anchor rope (4) includes a steel wire rope (41), a pressure-reducing ring (42) is installed on the steel wire rope (41), and a figure-eight rope (52) is connected to the end of the steel wire rope (41). A shackle (51) is installed on the figure-eight rope (52). The anchor point spacing of the pre-sensing pull-up anchor rope (4) meets the following requirements: d a1 =Min(αL,1) In the formula, d a1 d is the distance between two anchor points close to the projection line. a2 The distance between two anchor points far from the projection line is in meters; Min is a function that takes the smaller of the two values, α takes values ​​from 1 / 8 to 1 / 6, and L is the length of the column (22). c The column spacing in a passive flexible protection system.

5. A rockfall pre-sensing active avoidance steel column support system according to claim 4, characterized in that, The distance d from the center of the pin (13) to the midpoint of the line connecting the two anchor points close to the projection line. w The following requirements must be met: d w ≥Max(L,2vt) In the formula, Max is a function that takes the larger of the two values, v is the maximum impact velocity of falling rocks during the protection design, and t is the deflection reaction time of the steel column, which is taken as 0.08s.

6. The rockfall pre-sensing active avoidance steel column support system according to claim 1, characterized in that: The pulley (31) disc surface is parallel to the plane where the pre-sensing upward anchor rope (4) is located, and the pulley shaft (33) is perpendicular to the plane where the pre-sensing upward anchor rope (4) is located; the diameter of the groove of the pulley (31) is not less than 8 times the diameter of the wire rope (41) used for the pre-sensing upward anchor rope (4).

7. The rockfall pre-sensing active avoidance steel column support system according to claim 1, characterized in that: The yaw trajectory of the top node of the yaw steel column (2) is controllable and is determined by the following method: Let Oxyz be a right-handed rectangular coordinate system. The x-axis passes through four anchor points. The midpoint of the line connecting two anchor points close to the projection line is the origin O. The initial axis of the swaying steel column (2) lies in the yz plane. The swaying trajectory of the column top node is determined by the following formula: In the formula, y0 and z0 are the y and z coordinates of the center of the pin shaft (13), which are known quantities after the system configuration is determined. L a The length of a single pre-sensing pull-up anchor rope (4) is the sum of the distances from the two anchor points of the rope to the center of the pulley shaft (33), which is a known quantity, and b is an intermediate variable.

Images