A protection and retaining device for dangerous rockfalls with negative Poisson's ratio characteristics

Abstract

This application belongs to the field of slope rockfall protection, and particularly relates to a dangerous rock and rockfall protection and retaining device with negative Poisson's ratio characteristics. By designing the above-ground steel bar skeleton of the above-ground pile body in a form with negative Poisson's ratio characteristics, the dangerous rock and rockfall retaining device exhibits the characteristics of negative Poisson's ratio, and has the advantages of strong seismic performance, strong energy absorption capacity, small influence range of rockfall, and good plasticity. Through the design of the negative Poisson's ratio structure, the dangerous rock and rockfall protection and retaining device can provide better seismic resistance under earthquakes and impact forces, and effectively absorb and disperse impact and vibration energy. Its contraction characteristics can limit structural deformation and reduce the influence range of rockfall. Through the three-dimensional negative Poisson's ratio steel bar skeleton design and the gradient stirrup density design, it can effectively cope with the impact mechanics scenarios of dangerous rocks and rockfalls with high speed, high energy, three-dimensional stress waves, and pulse-type impact loads, and is applicable to areas with complex terrain and steep terrain.

Description

Technical Field

[0001] This application relates to the technical field of slope rockfall protection, and particularly to a dangerous rock and rockfall protection and retaining device with negative Poisson's ratio characteristics. Background Art

[0002] With the rapid development of China's transportation industry, infrastructure construction has been continuously expanding from plain and gentle hilly areas to mountainous and hilly areas with heavy topography. There are many mountains and hills in Southwest China, with complex terrain and steep terrain. During the process of transportation construction, dangerous rocks and rockfalls, as common geological disaster problems in railway engineering, pose a serious threat to railway lines and train operation safety. The rockfall protection retaining wall can prevent dangerous rocks and rockfalls from entering the railway track area, thus ensuring the safety of personnel and trains, protecting railway infrastructure, maintaining the normal operation of trains, reducing maintenance and repair costs, and improving the reliability and stability of railway lines. Therefore, in railway engineering, the structure of the rockfall protection retaining wall plays an important role and significance.

[0003] Conventional dangerous rock and rockfall protection retaining walls have deficiencies such as rigid limitations, local damage, and high maintenance costs. The negative Poisson's ratio structure provides a new idea for improving the impact resistance of the retaining structure. Compared with traditional structures, the negative Poisson's ratio structure has the property of "tensile dilation and compression", which endows it with excellent properties such as high energy absorption and reduction of the peak impact force. At the same time, the negative Poisson's ratio structure is usually made of high-strength materials, has good durability and impact resistance, and can withstand impact loads stably for a long time. Traditional retaining structures usually have a high stiffness, but are prone to local damage or failure under strong impacts, and their energy absorption capacity is limited, making it difficult to fully slow down the damage of rockfalls to the retaining structure. Although some traditional buffer structures can absorb a certain amount of energy, their energy absorption efficiency is low, and the buffering effect is limited, making it difficult to meet the requirements in complex geological disaster environments. The existing designs of negative Poisson's ratio columns in the prior art are often in the field of building construction, mainly for the composite stress scenarios of axial static loads and seismic dynamic loads, and most belong to the single-plane negative Poisson's ratio mechanism, with poor applicability to the dangerous rock and rockfall protection scenarios of pulse-type impacts and three-dimensional stress wave propagation characteristics. Therefore, how to improve the energy absorption capacity of the retaining structure, reduce the risk of structural damage, and at the same time ensure its efficient and durable protection performance has become a key technical problem to be solved. Summary of the Invention

[0004] The embodiments of this application provide a dangerous rock and rockfall protection and retaining device with negative Poisson's ratio characteristics, which is used to solve the problem of insufficient protection ability of the existing dangerous rock and rockfall protection and retaining structures in the face of high-energy, three-dimensional stress waves, and pulse-type impact loads.

[0005] To achieve the above object, the present application provides a rockfall protection retaining device with negative Poisson's ratio characteristics, which is characterized in that it includes retaining piles made of reinforced concrete. The retaining piles include underground foundations and above-ground pile bodies. The above-ground pile bodies are composed of concrete and above-ground steel skeletons. The above-ground steel skeletons exhibit negative Poisson's ratio characteristics. The above-ground steel skeletons include four erection bars and a plurality of stirrups. The four erection bars are arranged vertically and are respectively located at the four corners of a square. The erection bars are linearly connected by a plurality of first bent steel bar units along the vertical direction. The planes where adjacent two first bent steel bar units are located are perpendicular to each other. The plurality of stirrups are arranged at intervals from top to bottom on the four erection bars. The stirrups are formed by connecting four second bent steel bar units in a square shape. The four corners of adjacent two stirrups are respectively connected by four first bent steel bar units with the same longitudinal span. The bending directions of the two opposite second bent steel bar units on the stirrup are the same, and the bending directions of adjacent two second bent steel bar units are opposite, and the planes where each second bent steel bar unit is located are perpendicular to the horizontal plane.

[0006] Optionally, the vertical spacing between adjacent two stirrups gradually decreases from top to bottom, and the vertical spacing satisfies the following formula:

[0007] ;

[0008] In the formula, is the serial number of the layer where the stirrup is located from top to bottom, is the vertical spacing between the stirrup of the th layer and the stirrup of the th layer, is the spacing between adjacent erection bars, is the reduction coefficient of the stirrup spacing, The value range of

[0009] is 0.85 - 0.95; The longitudinal spans of the four first bent steel bar units on the erection bar between the stirrup of the th layer and the stirrup of the th layer are all equal to

[0010] Optionally, the spacing between adjacent two erection bars is 0.4m - 1.0m.

[0011] Optionally, each first bent steel bar unit is formed by connecting four first arc segments. The four first arc segments belonging to the same first bent steel bar unit are of equal length. The first bent steel bar unit is integrally convex, and the ratio of the longitudinal span to the transverse span is 16:1.

[0012] Optionally, the angle of the first arc segment of the first bent steel bar unit at the top of the erection bar is 14.25°;

[0013] Each of the second bent steel bar units has the same structure and is formed by connecting four equal-length second arc segments. The overall shape of the second bent steel bar unit is convex. The radius of curvature of the second bent steel bar unit in the direction of rockfall impact in the stirrup and the radius of curvature of the second bent steel bar unit perpendicular to the direction of rockfall impact Satisfy: The value range of is 1.5 - 2.0, The value range of is 0.5 - 0.8, where is the radius of curvature of the first arc segment in the first bent steel bar unit at the top of the erection bar.

[0014] Optionally, the underground foundation is composed of underground concrete and an underground steel bar framework. The underground foundation is integrally cast with the above-ground pile body. The side length of the cross-section of the underground foundation is 1.5 - 2.0 times the side length of the cross-section of the above-ground pile body, and the buried depth is 1 / 3 - 1 / 2 of the height of the above-ground pile body.

[0015] Optionally, the underground steel bar framework includes four underground erection bars and a plurality of underground stirrups. The upper ends of the four underground erection bars are respectively connected to the lower ends of the four erection bars. The underground erection bars are straight steel bars; the underground stirrups are formed by connecting four straight steel bars end to end, and a plurality of the underground stirrups are arranged at equal intervals from top to bottom on the four underground erection bars.

[0016] Optionally, the vertical spacing between two adjacent underground stirrups is 0.3m - 0.4m.

[0017] Optionally, a plurality of the rock-blocking piles are arranged in two rows in the direction of rockfall impact. The rock-blocking piles in each row are spaced apart in the direction perpendicular to the rockfall impact. The two rows of rock-blocking piles are staggered in the direction of rockfall impact.

[0018] Optionally, a plurality of the rock-blocking piles are arranged and combined in the direction perpendicular to the rockfall impact to form a rock-blocking wall.

[0019] The beneficial effects of the dangerous rock and rockfall protection and retaining device with negative Poisson's ratio characteristics provided by this application are as follows:

[0020] By designing the above-ground steel bar skeleton of the above-ground pile body in a form with negative Poisson's ratio characteristics, the dangerous rock and falling stone blocking device exhibits negative Poisson's ratio characteristics, and has the advantages of strong seismic resistance, strong energy absorption ability, small falling stone influence range, and good plasticity. Through the design of the negative Poisson's ratio structure, the dangerous rock and falling stone protection and blocking device can provide better seismic resistance under earthquakes and impact forces, and effectively absorb and disperse impact and vibration energy. Its shrinkage characteristics can limit structural deformation and reduce the influence range of falling stones. Through the three-dimensional negative Poisson's ratio steel bar skeleton design and the gradient stirrup density design, it can effectively cope with the impact mechanics scenarios of dangerous rocks and falling stones with high speed, high energy, three-dimensional stress waves, and pulse-type impact loads, and is applicable to areas with complex terrain and steep terrain, such as mountains and hills in the southwestern region of China. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Among them:

[0023] Figure 1 are the front view and right view of the stone-blocking pile in the dangerous rock and falling stone protection and blocking device shown in an embodiment of the present application;

[0024] Figure 2 is the perspective view of the stone-blocking pile shown in an embodiment of the present application;

[0025] Figure 3 is the schematic diagram of the steel bar skeleton in the stone-blocking pile shown in an embodiment of the present application;

[0026] Figure 4 is the schematic diagram of the first bending steel bar unit of the erection steel bars of the above-ground steel bar skeleton in the stone-blocking pile shown in an embodiment of the present application;

[0027] Figure 5 is the schematic diagram of the negative Poisson's ratio stone-blocking pile group shown in an embodiment of the present application;

[0028] Figure 6 is the schematic diagram of the negative Poisson's ratio stone-blocking wall shown in an embodiment of the present application;

[0029] Figure 7 is the schematic diagram of the numerical model;

[0030] Figure 8 is the comparison chart of the load-displacement curves of the traditional reinforced concrete hollow pile and the concrete hollow pile with a negative Poisson's ratio steel bar skeleton.

[0031] Description of the reference numerals:

[0032] 10. Underground foundation; 11. Underground concrete; 12. Underground steel reinforcement cage; 121. Underground erection bars; 122. Underground stirrups.

[0033] 20. Above-ground pile body; 21. Concrete; 22. Above-ground steel reinforcement cage; 221. Erection bars; 2211. First bent steel bar unit; 22111. First arc segment; 222. Stirrups; 2221. Second bent steel bar unit. Detailed implementation manners

[0034] For ease of understanding this application, the following will describe this application more comprehensively with reference to the relevant drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of this application more thorough and comprehensive.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0036] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of this application.

[0037] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality" and "several" is two or more, unless otherwise specifically defined.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0039] It should be noted that the existing negative Poisson's ratio column structures are mainly used for building beams and columns, often mainly targeting the composite stress scenarios of axial static loads and seismic dynamic loads. However, the protection structure for dangerous rock and falling rock has the following mechanical scenario specificities: (1) Instantaneous high-energy pulse-type impact load characteristics: The impact duration of the falling rock is about 50 - 200 ms, with an impact characteristic of the peak load per unit area > 5 MPa, significantly different from the conventional load of < 1 MPa for building structures; (2) Three-dimensional stress wave propagation characteristics: The stress wave velocity at the impact point > 2500 m / s requires the structure to have the ability of three-dimensional diffused stress waves; (3) High-frequency cumulative damage characteristics: The same component may bear cumulative damage with the number of annual impacts > 100 times.

[0040] In view of the above specificities of the mechanical scenarios of the protection structure for dangerous rock and falling rock, the design of the present invention is optimized for impact loads (such as falling rock impacts), especially in the design of the erection bars and stirrups, both of which adopt arc-shaped structures. This design method is specifically for dealing with the impacts of dangerous rock and falling rock, and can effectively absorb the impact energy and reduce the failure risk of the rock retaining pile. As Figures 1 - 3 shown, the protection and retaining device for dangerous rock and falling rock includes a rock retaining pile of reinforced concrete structure. The rock retaining pile includes an underground foundation 10 and an above-ground pile body 20. The above-ground pile body 20 is composed of concrete 21 and an above-ground steel bar framework 22. The above-ground steel bar framework 22 exhibits negative Poisson's ratio characteristics. The above-ground steel bar framework 22 includes four erection bars 221 and a plurality of stirrups 222. The four erection bars 221 are arranged vertically and are respectively located at the four corners of a square (side length is l). In order to make the structure have negative Poisson's ratio characteristics, the erection bars 221 are linearly connected vertically by a plurality of first bent steel bar units 2211, and the planes where two adjacent first bent steel bar units 2211 are located are perpendicular to each other; a plurality of stirrups 222 are arranged at intervals from top to bottom on the four erection bars 221. The stirrups 222 are formed by connecting four second bent steel bar units 2221 in a square shape. At the four corners of two adjacent stirrups 222, they are respectively connected by four first bent steel bar units 2211 with the same longitudinal span. In order to make the structure have negative Poisson's ratio characteristics, the bending directions of two opposite second bent steel bar units 2221 on the stirrup 222 are the same, the bending directions of two adjacent second bent steel bar units 2221 are opposite, and the planes where each second bent steel bar unit 2221 is located are perpendicular to the horizontal plane.

[0041] Through the collaborative design of the bidirectional alternating bending of the first bent reinforcement unit 2211 in the erection reinforcement 221 and the stirrups 222, a three-dimensional gradient dissipation mechanism is constructed to achieve targeted optimization. The alternating bending geometric characteristics of the first bent reinforcement unit 2211 extend the energy release path and the impact action time through wave-like collaborative deformation under impact, reduce the peak value of the instantaneous load, and at the same time, the negative Poisson's ratio effect induces lateral contraction, converts local high stress into multi-directional elastic deformation, reduces local stress concentration, effectively disperses the impact energy and reduces the peak stress. Aiming at the three-dimensional stress wave propagation characteristics, the stirrups 222 absorb the impact kinetic energy through elastic deformation, and combine the three-dimensional staggered deformation paths of the erection reinforcement 221 and the stirrups 222 to achieve the staggered dispersion of the three-dimensional stress wave in the longitudinal, transverse and depth directions. For the problem of high-frequency cumulative damage, the structure absorbs the impact energy through the three-dimensional gradient dissipation mechanism and inhibits the propagation of microcracks inside the concrete 21. Through the three-dimensional collaborative deformation of the erection reinforcement 221 and the stirrups 222, this design breaks through the limitations of the axial static load adaptation of building structures, targets and adapts to high-energy pulse impacts, complex stress wave propagation and dynamic fatigue scenarios, forms a systematic adaptation at the levels of load response, waveform dispersion and durability, provides an innovative structural solution for complex geological disaster scenarios, and realizes the systematic performance improvement of the dangerous rock and falling stone protection structure.

[0042] In the embodiment of the present application, by designing the above-ground steel bar skeleton 22 of the above-ground pile body 20 in a form with negative Poisson's ratio characteristics, the dangerous rock and falling stone blocking device exhibits the characteristics of negative Poisson's ratio, and has the advantages of strong seismic resistance, strong energy absorption ability, small falling stone influence range, light structure weight and good plasticity. Through the design of the negative Poisson's ratio structure, the dangerous rock and falling stone protection and blocking device can provide better seismic resistance under earthquakes and impact forces, and effectively absorb and disperse the impact and vibration energy. Its contraction characteristics can limit the structural deformation and reduce the influence range of falling stones. Through the three-dimensional negative Poisson's ratio steel bar skeleton design and the gradient stirrup 222 density design, it can effectively cope with the impact mechanics scenarios of dangerous rocks and falling stones with high speed, high energy, three-dimensional stress waves and pulse-type impact loads, and is applicable to areas with complex terrain and steep terrain, such as mountains and hills in the southwestern region of China.

[0043] In one embodiment, as Figures 1 - 3 shown, according to the different requirements for falling stone impact protection and site conditions, the spacing between adjacent two erection reinforcements 221 can be selectively set to 0.4 m - 1.0 m, that is, the side length of the square where the four erection reinforcements 221 are located is 0.4 m - 1.0 m. The stirrups 222 are distributed along the longitudinal direction of the stone-blocking pile with a gradient spacing. From top to bottom, the density of the stirrups 222 gradually increases, that is, the vertical spacing between adjacent two stirrups 222 gradually decreases from top to bottom, and the vertical spacing

[0044] ;

[0045] In the formula, is the serial number of the layer where the stirrup 222 is located from top to bottom, and the value range is 1, 2, 3, 4,..., n, is the layer stirrup 222 and the vertical spacing between the stirrups 222 of the layer, is the spacing between adjacent erection bars 221, is the reduction coefficient of the stirrup 222 spacing, The value range of is 0.85 - 0.95; the longitudinal spans of the four first bending bar units 2211 on the erection bar 221 between the stirrups 222 of the layer and the stirrups 222 of the layer are all equal to .

[0046] Reduction coefficient The value interval of can avoid the waste of materials caused by excessive densification of the stirrup 222 while ensuring the structural performance. If is too small (such as <0.85), it will cause the stirrup 222 spacing to be too dense, increasing the construction difficulty and the complexity of concrete pouring; if is too large (such as >0.95), it is difficult to achieve the gradient densification effect of the stirrup 222. This value range not only meets the requirements of structural strength but also takes into account economy, meeting the optimization principle of engineering design.

[0047] It can be seen from the above calculation formula that the vertical spacing between the two stirrups 222 at the upper end of the erection bar 221 is equal to the spacing between adjacent erection bars 221. This design not only simplifies the design calculation and construction process but also optimizes the material use and reduces the cost. Through the gradient densification design, the density of the bottom stirrup 222 is higher to enhance the flexural stiffness of the lower part of the pile body, adapt to the mechanical characteristics of the moment decreasing from bottom to top during the impact of falling rocks, and at the same time reduce the risk of local concrete cracking.

[0048] In an embodiment, as Figures 1 - 4 shown, each first bending bar unit 2211 is sequentially connected by four first arc segments 22111. The four first arc segments 22111 belonging to the same first bending bar unit 2211 are of equal length. The first bending bar unit 2211 is integrally convex, and the ratio of the longitudinal span to the transverse span is 16:1. The angle of the first arc segment 22111 of the first bending bar unit 2211 at the top of the erection bar 221 is 14.25°.

[0049] The second bent steel bar unit 2221 of the stirrup 222 has a similar structural form, except that its circular arc curvature has the characteristic of double curvature coupling. Specifically, each second bent steel bar unit 2221 has the same structure and is formed by connecting four equal-length second arc segments. The second bent steel bar unit 2221 is convex as a whole. Among the second bent steel bar units 2221 in the stirrup 222 along the direction of the falling rock impact ( Figure 2 shown in ), the radius of curvature and the radius of curvature of the second bent steel bar unit 2221 perpendicular to the direction of the falling rock impact ( Figure 2 shown as b in ) satisfy: The value range of is 1.5 - 2.0, and the value range of is 0.5 - 0.8, where is the radius of curvature of the first arc segment 22111 in the first bent steel bar unit 2211 at the top of the erection bar 221.

[0050] The larger longitudinal radius of curvature makes the structure more likely to undergo elastic bending deformation absorption when subjected to impact, and drives the adjacent units to form a wingspan effect (the middle of the unit expands outwards, driving the adjacent units to deform synergistically); the smaller transverse radius of curvature forms a local high-stiffness area. When the corrugated unit is subjected to transverse shear (oblique impact of falling rocks), stress wave reflection occurs at the curvature mutation, reducing transverse deformation and enhancing shear resistance. The combined design of longitudinal and transverse curvatures enables the structure to exhibit different responses under loads in different directions, achieving three-dimensional gradient dissipation (energy gradually decays along the longitudinal, transverse, and depth directions).

[0051] In one embodiment, as Figures 1 - 3 shown, the underground foundation 10 is composed of underground concrete 11 and an underground steel bar skeleton 12. The underground foundation 10 is integrally cast with the above-ground pile body 20. The side length of the cross-section of the underground foundation 10 is 1.5 - 2.0 times the side length of the cross-section of the above-ground pile body 20, and the buried depth is 1 / 3 - 1 / 2 of the height of the above-ground pile body 20.

[0052] Among them, the underground steel bar skeleton 12 includes four underground erection bars 121 and a plurality of underground stirrups 122. The upper ends of the four underground erection bars 121 are respectively connected to the lower ends of the four erection bars 221. The underground erection bars 121 are straight steel bars; the underground stirrups 122 are formed by connecting four straight steel bars end to end. A plurality of underground stirrups 122 are arranged at equal intervals from top to bottom on the four underground erection bars 121. The vertical spacing between two adjacent underground stirrups 122 is 0.3 m - 0.4 m.

[0053] The above design significantly enhances the overall stability and impact resistance of the rock retaining pile. The larger lateral cross-sectional dimension improves the anti-overturning and shear resistance of the foundation, effectively dispersing the impact load of the falling rocks; the reasonable embedment depth makes full use of the lateral restraint and self-weight of the soil, enhancing the anti-pulling and anti-sliding performance and ensuring the stability of the pile under extreme loads. At the same time, on the basis of meeting the structural performance requirements, this design avoids the economic waste caused by excessive expansion of the foundation size or increase of the embedment depth, achieving the balance between economy and performance. In addition, this design has high construction feasibility and strong adaptability, and can be applied to various geological conditions, providing a reliable guarantee for the long-term stable operation of the rock retaining pile in various environments. The underground steel skeleton 12 of the underground foundation 10 adopts a regular framework composed of straight underground erection bars 121 and underground stirrups 122, with a simple structure and low cost. The underground erection bars 121 and underground stirrups 122 form a rigid restraint, enhancing the shear resistance and anti-overturning ability of the foundation.

[0054] In a specific embodiment, the above-ground pile body 20 of the rock retaining pile is 3.125 m high, and the cross-section is a square with a side length of 0.5 m. The lateral cross-sectional dimension of the underground foundation 10 is 0.75 m × 0.75 m, and the embedment depth is 1.1 m.

[0055] It should be noted that the rock retaining pile can be designed as a hollow structure according to the actual working conditions. The setting of the hollow rock retaining pile is applicable to situations such as reducing self-weight to adapt to the foundation bearing capacity, saving material costs, enhancing impact energy absorption capacity, optimizing construction efficiency, and meeting multi-functional requirements. The hollow design can reduce the weight of the pile body, reduce the pressure on the foundation, and at the same time absorb the impact energy through the deformation of the inner wall, improving the impact resistance. In addition, the hollow structure is convenient for transportation and installation, especially suitable for areas with complex terrain. However, in the design, it is necessary to ensure that the strength and wall thickness of the pile body are reasonable to prevent local instability, and at the same time take protective measures to avoid water accumulation or corrosion to ensure the safety and durability of the structure.

[0056] In some embodiments, as Figure 5 shown, multiple rock retaining piles are arranged in two rows in the direction of the falling rock impact. The rock retaining piles in each row are spaced at intervals in the direction perpendicular to the falling rock impact, and the two rows of rock retaining piles are staggered in the direction of the falling rock impact.

[0057] As one of the preferred installation methods, different sizes of stone-blocking piles and different pile group settings can be used in actual projects according to different protection requirements for dangerous rockfalls. In addition to blocking dangerous rockfalls, stone-blocking pile groups can also be used to intercept and dissipate energy for debris flows. Traditional stone-blocking walls are only suitable for intercepting falling rocks, but they are less effective in intercepting debris flows, because the wall loses its interception effect after a large debris flow overflows the wall. However, stone-blocking pile groups can allow fluids and small solids to pass through, while intercepting large solids, which can greatly reduce the impact energy of the debris flow and thus reduce the damage range of the debris flow. When the stone-blocking piles are impacted, the steel skeleton with a negative Poisson's ratio effect has a stronger restraining effect on the concrete than the traditional steel skeleton, thereby improving the impact resistance of the stone-blocking piles.

[0058] In other embodiments, Figure 6 As shown, a plurality of rock retaining piles are arranged and combined perpendicular to the direction of rockfall impact to form a rock retaining wall.

[0059] Specifically, the steel skeletons of the rock-blocking piles are arranged in the transverse direction to form a steel skeleton of the rock-blocking wall. The steel skeleton of the rock-blocking wall and the concrete 21 form a rock-blocking wall with negative Poisson's ratio characteristics.

[0060] Rockfall protection walls with negative Poisson's ratio characteristics have a series of significant advantages. First, they provide stronger seismic resistance and can reduce the impact of earthquakes or other dynamic loads on the structure. By utilizing the characteristics of negative Poisson's ratio structures, the structure can shrink laterally when subjected to force, reducing deformation and stress concentration, thereby improving the overall seismic resistance. Secondly, the rockfall protection wall with negative Poisson's ratio structure can have a higher energy absorption capacity and can effectively absorb impact and vibration energy, thereby reducing the risk of structural damage. In addition, the contraction characteristics of the negative Poisson's ratio structure can limit the deformation range of the structure, thereby reducing the impact range of the rockfall. This is crucial to protecting the surrounding environment and the safety of nearby personnel. Negative Poisson's ratio rockfall walls can reduce the ejection distance of stones and the splash range of fragments, effectively controlling the scope of damage caused by rockfall.

[0061] In addition to the above-mentioned implementation methods, the negative Poisson's ratio rock-blocking pile and rock-blocking wall structure can also be combined into a pile-board rock-blocking wall. In actual projects, different combinations and geometric layouts of rock-blocking structures can be adopted according to different terrain, geology, rockfall characteristics, structural stability and other requirements, which may include the selection of rock-blocking piles / rock-blocking walls, the height of the structure, the inclination angle, the dumping method and the spacing between structures. Ensure that the rock-blocking structure can effectively intercept and block rockfall and reduce its impact on the surrounding environment.

[0062] Similarly, the above design method can also be applied to reinforced rubber rock retaining piles and reinforced rubber rock retaining walls. The reinforced concrete material can be replaced with reinforced rubber, the concrete 21 is replaced with rubber, and the steel bars are replaced with high-strength synthetic fibers.

[0063] In order to verify the effect of the negative Poisson's ratio structure in enhancing the flexural strength and toughness of concrete rock retaining piles, based on the finite element analysis software ABAQUS, the present invention establishes three-dimensional models of a traditional reinforced concrete hollow pile and a concrete hollow pile with a negative Poisson's ratio steel bar skeleton, and conducts numerical simulations of four-point bending tests on the two structures. By comparing the load-displacement curves of the two, the enhancing effect of the negative Poisson's ratio structure on the flexural performance of the concrete column is analyzed.

[0064] As Figure 7 shown, both models adopt the same material parameters, geometric dimensions and loading methods. By comparing their load-displacement curves, the flexural strength and toughness performance are evaluated. The steel bar skeleton of the traditional concrete hollow pile consists of traditional straight erection bars and stirrups, and the steel bar skeleton of the concrete hollow pile with negative Poisson's ratio is a negative Poisson's ratio structure. Simply supported boundary conditions are applied at both ends of the concrete column. A displacement load is applied in the loading area to simulate the mechanical loading process of the test. Through numerical calculation, the load-displacement curves of the traditional concrete pile and the concrete pile with negative Poisson's ratio structure are obtained, as Figure 8 shown. The peak load of the traditional concrete column is 344 kN, and the peak load of the concrete column with negative Poisson's ratio is 368 kN, which is about 7% higher than that of the traditional column, significantly enhancing the flexural strength. At the same time, the areas under the curves of the two structures are not significantly different, indicating that the negative Poisson's ratio structure does not significantly reduce the toughness performance while maintaining a high energy absorption capacity.

[0065] The numerical simulation results prove that the negative Poisson's ratio structure effectively improves the flexural strength of the concrete pile, and the increase in the peak load verifies the enhancing effect of the negative Poisson's ratio characteristics of the steel bar skeleton on the overall structural performance. This is mainly attributed to the fact that the negative Poisson's ratio structure can effectively disperse stress concentration during the deformation process, improving the bearing capacity of the structure. The concrete pile with negative Poisson's ratio structure of the present invention shows superiority in both flexural strength and toughness. The application of the negative Poisson's ratio structure enables the concrete pile to have better comprehensive performance under high-strength load conditions, and has important practical application value in enhancing the safety and stability of engineering structures. It is particularly suitable for the protection engineering of dangerous rock falls with high impact and high flexural strength requirements, and has important application value.

[0066] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0067] The above embodiments only represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A rockfall protection and blocking device with negative Poisson's ratio, characterized in that: A stone-blocking pile comprising a reinforced concrete structure, wherein the stone-blocking pile comprises an underground foundation and an above-ground pile body, wherein the above-ground pile body is composed of concrete and an above-ground steel bar skeleton, wherein the above-ground steel bar skeleton exhibits a negative Poisson's ratio characteristic, and wherein the above-ground steel bar skeleton comprises four frame bars and a plurality of stirrups, wherein the four frame bars are arranged vertically and are respectively located at the four corners of a square, wherein the frame bars are formed by a plurality of first curved steel bar units connected linearly along a vertical direction, and the planes where two adjacent first curved steel bar units are located are perpendicular to each other; wherein a plurality of stirrups are arranged at intervals from top to bottom on the four frame bars, wherein the stirrups are formed by four second curved steel bar units connected in a square shape, and the four corners of two adjacent stirrups are respectively connected by four first curved steel bar units with the same longitudinal span, wherein the bending directions of two opposite second curved steel bar units on the stirrups are the same, and the bending directions of two adjacent second curved steel bar units are opposite, and the planes where each second curved steel bar unit is located are perpendicular to the horizontal plane; Each first curved steel bar unit is formed by connecting four first arc segments, and the four first arc segments belonging to the same first curved steel bar unit are of equal length. The first curved steel bar unit is convex as a whole, and the longitudinal to transverse span ratio is 16:1; The angle of the first arc segment of the first curved steel bar unit at the top end of the frame bar is 14.25°; Each of the second curved steel bar units has the same structure, and is formed by connecting four second arc segments of equal length. The second curved steel bar unit is convex as a whole, and the curvature radius of the second curved steel bar unit in the stirrup along the direction of rockfall impact is R v and the curvature radius of the second curved reinforcement element perpendicular to the rockfall impact direction R h satisfy: R v / R The value range is 1.5-2.0, R h / R The value range is 0.5-0.8, where R It is the radius of curvature of the first arc segment in the first curved reinforcement unit at the top of the reinforcement.

2. The device for preventing and blocking dangerous rocks and falling rocks according to claim 1 is characterized in that: The vertical spacing between two adjacent stirrups d n It gradually decreases from top to bottom, and the vertical spacing d n Satisfies the following formula: ； In the formula, n It is the serial number of the layer where the stirrups are located from top to bottom. d n It is n Layer stirrups and the first n+1 The vertical spacing of layer stirrups, l is the spacing between adjacent reinforcement bars, a is the reduction factor for the stirrup spacing, a The value range of is 0.85-0.95; The frame reinforcement is located at the n Layer stirrups and the first n+1 The longitudinal spans of the four first bending reinforcement elements between the layer stirrups are equal to d n .

3. The device for preventing and blocking dangerous rocks and falling rocks according to claim 1 is characterized in that: The spacing between two adjacent reinforcement bars is 0.4m-1.0m.

4. The device for preventing and blocking dangerous rocks and falling rocks according to any one of claims 1 to 3, characterized in that: The underground foundation is composed of underground concrete and underground steel frame. The underground foundation and the above-ground pile body are cast as one piece. The cross-sectional side length of the underground foundation is 1.5-2.0 times the cross-sectional side length of the above-ground pile body, and the burial depth is 1 / 3-1 / 2 of the height of the above-ground pile body.

5. The device for preventing and blocking dangerous rocks and falling rocks according to claim 4 is characterized in that: The underground steel bar skeleton includes four underground frame bars and multiple underground stirrups. The upper ends of the four underground frame bars are respectively connected to the lower ends of the four frame bars. The underground frame bars are straight steel bars. The underground stirrups are formed by connecting four sections of straight steel bars end to end. The multiple underground stirrups are arranged at equal intervals from top to bottom on the four underground frame bars.

6. The device for preventing and blocking dangerous rocks and falling rocks according to claim 5 is characterized in that: The vertical spacing between two adjacent underground stirrups is 0.3m-0.4m.

7. The device for preventing and blocking dangerous rocks and falling rocks according to claim 1 is characterized in that: The plurality of rock-blocking piles are arranged in two rows in the direction of rockfall impact, the rock-blocking piles in each row are spaced apart perpendicular to the direction of rockfall impact, and the two rows of rock-blocking piles are staggered with each other in the direction of rockfall impact.

8. The device for preventing and blocking dangerous rocks and falling rocks according to claim 1 is characterized in that: A plurality of the rock-blocking piles are arranged and combined in a direction perpendicular to the impact direction of falling rocks to form a rock-blocking wall.

Images