Mountain debris flow flexible composite barrier device

Abstract

The invention relates to the technical field of mountainous geological disaster protection, discloses a flexible composite barrier device for debris flow in a mountainous area, and aims to realize efficient debris flow protection and guarantee downstream life and property safety through segmented interception and energy consumption. According to the device, a plurality of anchoring and pulling and flexible blocking net combined structures are adopted, three blocking nets are arranged along the debris flow scouring path, and each blocking net is arranged on the two sides of a ditch in a striding mode along a cross slope. According to the specific structure, a concrete anchoring support is excavated and poured on a stable bank slope of the ditch, a steel sleeve is reserved at the top of the support, and a high-strength steel vertical rod is inserted into the steel sleeve to form bottom build-in; the top end of each steel vertical rod is provided with a longitudinal slope direction tie steel cable, and the far end of the steel cable is anchored on an upstream stable bank slope to form top tie; transverse steel cables are tied to the tops and the bottoms of the adjacent steel vertical rods respectively, a replaceable flexible steel blocking net is connected between the two transverse steel cables in a buckled mode, and holes of the steel blocking nets are gradually reduced from the upstream to the downstream. When the device works, the first blocking net intercepts large stones and coarse particles, the second blocking net reduces the flow speed and intercepts small and medium particles, the third blocking net filters residual impurities and weakens fluid kinetic energy, and finally debris flow is converted into a common mountain stream. Standardized design and installation are adopted, large-scale foundation excavation is not needed, system maintenance is easy and convenient, cost is low, and a full-path barrier of the stone flow risk can be formed.

Description

Technical Field

[0001] This technology belongs to the field of geological disaster prevention and protection engineering. It is used in mountainous debris flow risk areas. It uses multiple flexible barrier nets to intercept debris flows and create energy barriers, thus protecting the safety of life and property downstream. Background Technology

[0002] Debris flows are short-lived, special types of floods in mountainous valleys, triggered by torrential rains, snowmelt, or dam failures, carrying large amounts of mud, sand, rocks, and boulders. As a special type of flood carrying large amounts of solid debris, debris flows are characterized by their suddenness, high velocity, and immense destructive power. More than 10,000 debris flow gullies are distributed in the mountainous areas of southwest and northwest my country. According to the "2024 China Natural Resources Bulletin" released by the Ministry of Natural Resources, a total of 5,719 geological disasters occurred nationwide in 2024, including 727 debris flow disasters, seriously threatening downstream towns, transportation, and the safety of life and property. The "8.3" catastrophic debris flow in Kangding, Sichuan, instantly buried a highway bridge and temporarily cut off rescue channels, making it the deadliest single debris flow event in 2024. In areas affected by strong earthquakes, the accumulation of large amounts of loose material due to fractured rock masses exacerbates the risk of frequent debris flow disasters, creating a persistent and difficult problem of recurring damage.

[0003] Existing protective measures have significant drawbacks: traditional rigid sand dams, while capable of retaining sediment, have short lifespans, are prone to siltation, and suffer from long construction periods, high costs, and disruption of aquatic ecosystems and biological migration; gravity retaining walls and similar structures have stringent foundation requirements and are susceptible to instability due to foundation erosion in areas with complex terrain. Some flexible barriers are only suitable for small to medium-sized dilute debris flows, exhibiting low interception efficiency against high-density viscous debris flows, and their single-channel deployment makes it difficult to achieve graded energy dissipation.

[0004] Meanwhile, existing engineering projects are mostly designed as individual projects, neglecting synergistic effects, and are unable to cope with the combined threat of debris flows, which involve "large particle impact, transport of small and medium-sized particles, and release of fluid energy." Therefore, there is an urgent need for a new protection technology that combines terrain adaptability, tiered protection capabilities, and ecological compatibility to overcome the functional limitations of traditional solutions. Summary of the Invention

[0005] I. Overall Structural Design The core of this invention is to deploy multiple sets of "anchoring and tying + flexible netting" combinations on both sides of the ditch along the debris flow scour path. Each set of structures works together to form a graded protection system, and the overall structure is designed around the core requirements of graded protection.

[0006] 1. Anchoring support and steel vertical rod embedment: Excavate foundation pits on the stable slopes on both sides of the ditch, pour concrete anchoring supports, and pre-install steel sleeves matching the steel vertical rods at the top of the supports. The depth of the steel sleeves must meet the rigidity requirements to ensure that after the high-strength steel vertical rods are inserted, the anti-lateral displacement and anti-overturning performance of the concrete supports can form a stable embedment at the bottom of the steel vertical rods, preventing root displacement of the steel vertical rods when impacted by debris flows.

[0007] 2. Top tie of steel vertical poles: 2-3 tie steel cables (preferably high-strength galvanized steel cables) are symmetrically installed at the top of each steel vertical pole along the longitudinal slope. The far end of the steel cable is anchored to the intact rock layer of the stable upstream bank slope through anchor rods, forming a two-way fixed structure of "bottom embedding + top tie", which further prevents the steel vertical pole from tilting or falling due to the lateral impact force of debris flow.

[0008] 3. Horizontal steel cable and flexible steel fence fixing: A horizontal steel cable is horizontally tied to the top and bottom of each of two adjacent steel vertical poles. The two horizontal steel cables are parallel and the spacing is set according to the height of the steel fence. The replaceable flexible steel fence (made of high-toughness steel wire woven or knotted, with metal buckles on the edge) is tightly connected to the horizontal steel cable through the buckles. At the same time, the two sides of the steel fence are fixed to the steel vertical poles through the buckles to ensure that the steel fence will not fall off or shift when impacted.

[0009] 4. Three-tiered steel barrier installation: Three layers of the aforementioned flexible steel barrier are installed sequentially along the debris flow direction (from upstream to downstream), with the mesh size gradually decreasing. Preferably, the mesh size of the first steel barrier is 15-25cm, the second is 8-15cm, and the third is 3-5cm. The spacing between adjacent steel barriers is adjusted according to the slope of the ditch (usually the distance between the first and second barriers is 50-80m, and the distance between the second and third barriers is 30-50m), achieving the core design goal of tiered interception.

[0010] II. Principle of Tiered Interception and Energy Consumption The three steel barriers work together according to their functional positioning to achieve segmented energy consumption and step-by-step filtration: 1. First steel barrier (upstream): As the first line of protection upstream, it is specifically designed to intercept large rocks and coarse particles with a diameter of 30cm or more at the forefront of the debris flow. These particles have the greatest impact kinetic energy. The tensile strength and toughness of the flexible steel barrier directly buffer and block them, which can not only prevent large particles from hitting downstream structures, but also initially dissipate the impact kinetic energy of the debris flow through the collision and buffer deformation between the particles and the net.

[0011] 2. Second steel barrier (midstream): As a midstream buffer, the mesh slows down the overall flow velocity of the debris flow through the friction between the mesh and the debris flow fluid and small particles with a diameter of 5-30cm (usually reducing the flow velocity by 30%-50%). At the same time, the mesh intercepts some small particles, reducing the solid particle content in the fluid and further weakening the pushing and impact force of the debris flow.

[0012] 3. Third steel barrier (downstream): As the final downstream filtration and protection, it filters out the remaining fine impurities with a diameter of less than 5cm. At this point, the debris flow has already lost a lot of energy after passing through the first two interceptions. The third steel barrier continuously buffers and weakens the remaining kinetic energy, ultimately reducing the debris flow velocity to below 1m / s and the solid particle content to more than 90%, transforming it into a normal mountain stream without destructive power.

[0013] III. Advantages of the Equipment This device boasts significant advantages in design and application: it adopts a fully standardized design, with relatively uniform anchor support dimensions, steel vertical rod specifications, steel cable parameters, and steel mesh dimensions. Installation requires no large-scale excavation (only a small foundation pit is needed for casting the supports), making it suitable for complex mountainous terrain. Maintenance only requires periodic checks of steel cable tension and support anchorage; if the steel mesh is damaged, it can be disassembled and replaced individually (without overall removal), reducing maintenance costs by more than 40% compared to traditional rigid structures. Through the synergistic effect of the "anchoring tie structure + three-tiered steel mesh," it forms a full-path protection system from "intercepting large particles" to "weakening kinetic energy," effectively addressing the functional deficiencies of traditional solutions. Attached Figure Description

[0014] Figure 1 This is a three-dimensional overall perspective view of one of the barrier net structures in the device of the present invention. Figure 2 This is a three-dimensional perspective view of the anchor support in the device.

[0015] The core components of the device of this invention consist of three flexible composite barriers. The structures of each flexible composite barrier are basically the same, except that the aperture size of the flexible mesh varies at different locations. The specific structure is as follows: concrete anchor support (1), reserved steel sleeve (2), steel vertical rod (3), longitudinal tie cable (4), steel cable anchoring end (5), top transverse tie cable (6), bottom transverse tie cable (7), replaceable flexible steel mesh (8), and mesh edge lock (81). In addition, this device is installed on both sides of the ditch (9) in the debris flow erosion path in mountainous areas.

[0016] Figure 1 The figure shows the overall installation status of any flexible barrier structure in the device on both sides of a mountain ditch. As can be seen in the figure, two sets of core structural units are symmetrically arranged on the left and right banks of the ditch (9): the bottom of each unit is a block concrete anchor support (1), and a steel sleeve (2) is reserved in the anchor support (1). A steel vertical rod (3) is vertically inserted into the sleeve (2), and the bottom end of the steel vertical rod (3) is completely embedded in the steel sleeve (2) to form a bottom fixation; two inclined longitudinal tie steel cables (4) are symmetrically connected on both sides of the top of each steel vertical rod (3). The steel cables (4) extend upward along the longitudinal slope and the far end is connected to the wedge-shaped steel cable anchor end (5). The steel cable anchor end (5) is embedded in the stable foundation of the upstream bank slope to form a top tie system.

[0017] At the same time, the top of the steel vertical poles (3) on the left and right sides are horizontally connected with the top horizontal tie steel cable (6), and the bottom of the steel vertical poles (3) are horizontally connected with the bottom horizontal tie steel cable (7). The two horizontal steel cables are parallel and the spacing is adapted to the height of the replaceable flexible steel net (8). The flexible steel net (8) is circular or polygonal. The net edge buckle (81) is fastened and fixed with the top and bottom horizontal tie steel cables (6) and (7). The two sides of the net are connected to the steel vertical poles (3) through the net edge buckle (81). The whole structure forms a stable combination structure of "vertical support - horizontal tie - net fixing", clearly showing the complete assembly relationship of the single net.

[0018] Figure 2 The detailed structure of the concrete anchor support (1) is shown separately under magnification. The support (1) is a block structure, which is poured with concrete after the foundation is excavated. A steel sleeve (2) is reserved in the center of the top of the support. The sleeve (2) is poured into the support concrete as a whole. The inner diameter of the sleeve matches the outer diameter of the steel vertical rod (3). The depth of the sleeve is not less than 1 / 2 of the height of the support to ensure that the steel vertical rod has sufficient embedment strength after insertion.

[0019] It should be noted that the three-layer barrier structure of the device is constructed in accordance with... Figure 1 Consistent, only the size of the holes in the replaceable flexible steel mesh (8) gradually decreases from upstream to downstream. The attached diagram shows the design logic of the overall graded protection of the complete support device through the details of the single structure and core components. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0021] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0022] The specific implementation of this invention needs to be carried out in conjunction with the actual terrain of the debris flow erosion path in mountainous areas.

[0023] I. Preliminary Preparations and Site Survey First, a geological survey was conducted on both sides of the ditch (9) along the debris flow path in the mountainous area to determine the stable slope area as the installation point of the device, avoiding loose rock layers or landslide-prone areas, and ensuring that the foundation bearing capacity of the concrete anchor support (1) meets the requirements; at the same time, based on the width, slope and historical debris flow scale of the ditch (9), the installation spacing of three replaceable flexible steel nets (8) was planned, and the installation height and lateral coverage of each net (8) were clarified.

[0024] II. Core Structure Installation Process 1. Assembly of anchor support and steel vertical rod: Excavate a small foundation pit at the surveyed location and pour concrete anchor support (1). During the pouring process, embed the reserved steel sleeve (2) simultaneously to ensure that the sleeve (2) and the support (1) are poured together and are perpendicular to the slope surface. After the concrete strength reaches the standard, insert the steel vertical rod (3) vertically into the reserved steel sleeve (2). Through the close cooperation between the sleeve (2) and the steel vertical rod (3), the bottom of the steel vertical rod (3) is embedded to prevent root displacement when it is impacted.

[0025] 2. Tie system construction: Install longitudinal tie steel cables (4) symmetrically on both sides of the top of each steel vertical pole (3). One end of the steel cable (4) is fixed to the connector at the top of the steel vertical pole (3), and the other end extends upward along the longitudinal slope until the complete rock layer of the stable upstream bank slope. The steel cable anchor end (5) is inserted through drilling and the steel cable (4) is connected and fixed to the anchor end (5) to form a two-way fixed structure of "bottom embedding + top tie". Then tie the top horizontal tie steel cable (6) between the tops of adjacent steel vertical poles (3) and tie the bottom horizontal tie steel cable (7) between the bottoms to ensure that the two horizontal steel cables (6) and (7) are parallel and the spacing is adapted to the height of the replaceable flexible steel fence (8).

[0026] 3. Installation of flexible steel netting: The replaceable flexible steel netting (8) is fastened and fixed to the top horizontal tie steel cable (6) and the bottom horizontal tie steel cable (7) by the netting edge lock (81). At the same time, the netting edge lock (81) is used to connect the two sides of the steel netting (8) to the steel vertical pole (3) to prevent the netting (8) from shifting or falling off when impacted by debris flow. The installation of the three nettings (8) is completed in the same process. Only the netting (8) with the corresponding mesh size is selected according to the graded protection requirements from upstream to downstream.

[0027] III. Graded Protection Operation and Maintenance When a debris flow occurs, the first barrier net (8) upstream intercepts large rocks and coarse particles, buffering the impact through the toughness of the net body; the second barrier net (8) in the middle reaches reduces the flow velocity by means of the friction of the net body, intercepting small and medium-sized particles; the third barrier net (8) downstream filters the remaining impurities and weakens the kinetic energy, ultimately turning the debris flow into a normal mountain stream. In daily maintenance, the tension of the longitudinal tie cables (4), the top transverse tie cables (6), and the bottom transverse tie cables (7) are checked regularly, and the concrete anchor support (1) is checked for cracks or displacement; if the replaceable flexible steel barrier net (8) is damaged, it is only necessary to unlock the edge buckle (81), remove the damaged barrier net (8) and replace it with a new net, without disassembling the entire device structure. Example

[0028] This embodiment is applied to a typical debris flow gully in the southwestern mountainous area. The gully is 15-20m wide and has a longitudinal slope of 15°. It has a history of medium-sized viscous debris flows. Three flexible composite barriers need to be deployed to achieve full-path protection. The specific parameters and implementation process are as follows.

[0029] I. Basic Parameter Settings Based on the valley topography, the concrete anchor support (1) is made of C30 concrete and is a block column with a diameter of 1.2m and a height of 1.8m. The reserved steel sleeve (2) is made of Φ150mm steel pipe with a length of 1.2m (bottom sealed) and a wall thickness of 8mm. It is fixed coaxially with the steel reinforcement skeleton of the support (1) during pouring. The steel vertical rod (3) is made of Q355 high-strength steel with a diameter of Φ140mm and a length of 5.2m. It is inserted into the sleeve (2) to a depth of 1.2m and exposed to a height of 4.0m.

[0030] II. Core Component Installation Anchoring and tying system: The longitudinal tying steel cable (4) is a Φ18mm high-strength galvanized steel cable (tensile strength 1800MPa). Two cables are symmetrically arranged at the top of each steel vertical rod (3). The far end of the steel cable is embedded into the upstream intact rock layer 1.5m deep through a Φ28mm threaded steel anchor rod (steel cable anchoring end (5)). The top transverse tying steel cable (6) and the bottom transverse tying steel cable (7) are both Φ18mm galvanized steel cables. The distance between adjacent steel vertical rods (3) is 12m, and the distance between the two transverse steel cables is 3.5m (to match the height of the fence).

[0031] Flexible steel fence assembly: The replaceable flexible steel fence (8) is woven with high-toughness galvanized steel wire, and the mesh edge lock (81) is made of galvanized material; the first fence (8) upstream has an aperture of 18cm and a distance of 60m from the second fence; the second fence (8) has an aperture of 10cm and a distance of 40m from the third fence; the third fence (8) has an aperture of 4cm and is fixed to the horizontal steel cables (6) and (7) and the steel vertical rod (3) by the mesh edge lock (81). Each fence covers a valley width of 12m horizontally.

[0032] III. Application Effects During a mudslide triggered by a rainstorm, the first barrier net (8) successfully intercepted more than 120 rocks with a diameter of 30-80cm, buffering the impact kinetic energy; the second barrier net (8) reduced the mud and water flow velocity from 3.2m / s to 1.8m / s, intercepting about 60% of the 5-30cm particles; the third barrier net (8) filtered out the remaining fine particles, and the final outflowing water velocity was 0.8m / s, with a solid content of less than 5%, transforming into ordinary mountain stream water. In daily maintenance, only the tension of the steel cables needs to be checked every quarter, and the partially damaged barrier net (8) needs to be replaced and the accumulated layer needs to be removed the following year. The maintenance cost is low and the operation is simple.

[0033] This invention is designed for debris flow protection in mountainous areas. It can efficiently intercept solid particles in stages and gradually weaken the fluid's kinetic energy, avoiding the hazards of large particle impacts and high flow velocities. It requires no large-scale excavation and is suitable for complex mountainous terrain; the steel mesh can be disassembled and replaced individually, making maintenance simple and quick. It forms a complete protection system along the entire path, effectively ensuring the safety of downstream towns, transportation, and life and property, with an overall cost significantly lower than traditional rigid structures.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A flexible composite barrier device for debris flow in mountainous areas, characterized in that: Multiple sets of anchoring and tie structures combined with flexible netting are installed on both sides of the ditch along the debris flow scour path. The assembly includes: 1) concrete anchoring supports excavated and poured on the stable bank slope of the ditch, with a steel sleeve pre-installed at the top of the support, into which high-strength steel vertical rods are inserted to form bottom fixation; 2) tie cables extending longitudinally along the top of each steel vertical rod, with the far end of the cable anchored to the upstream stable bank slope to form top tie of the steel vertical rod; 3) transverse tie cables are installed at the top and bottom of two adjacent steel vertical rods, and replaceable flexible steel netting is fastened between the two transverse tie cables; 4) three flexible steel nettings are sequentially installed along the debris flow scour direction, with the mesh size of each flexible steel netting gradually decreasing from upstream to downstream; 5) the three flexible steel nettings achieve segmented energy dissipation and step-by-step interception and filtration of the debris flow, buffering and absorbing the impact kinetic energy of the debris flow and intercepting its solid particles.

2. The flexible composite barrier device for debris flow in mountainous areas as described in claim 1, characterized in that: The first flexible steel barrier, located at the very upstream, is used to intercept large rocks and coarse particles in debris flows, achieving initial interception of solid particles in debris flows.

3. The flexible composite barrier device for debris flow in mountainous areas as described in claim 1 or 2, characterized in that: The second flexible steel barrier, located downstream of the first flexible steel barrier, reduces the velocity of the debris flow through friction and structural blocking, while intercepting small and medium-sized particles in the debris flow, reducing the sediment content of the debris flow and weakening its fluid impact force.

4. The flexible composite barrier device for debris flow in mountainous areas as described in any one of claims 1 to 3, characterized in that: The third flexible steel barrier, located downstream of the second flexible steel barrier, is used to filter out remaining impurities in the debris flow, further weakening the flow energy and destructive force of the debris flow, so that the debris flow after passing through the steel barrier is transformed into ordinary mountain stream water.

5. The flexible composite barrier device for debris flow in mountainous areas as described in claim 1, characterized in that: The device adopts a standardized design, eliminating the need for large-scale excavation; the flexible steel barrier is replaceable, making maintenance simple and cost-effective; through the synergistic effect of three flexible steel barriers and anchoring structures, a full-path debris flow protection system is formed, effectively protecting downstream life and property in mountainous debris flow risk areas and achieving efficient debris flow protection.

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