Debris flow flexible protective net design method based on cooperation of energy matching and force balance

Abstract

The invention discloses a debris flow flexible protective net design method based on cooperation of energy matching and force balance, and belongs to the technical field of geological disaster prevention and control engineering. According to the method, debris flow impact energy is distributed to energy dissipaters at all parts according to a preset proportion, and scientific preliminary selection and matching of structural components are achieved; a continuous impact process is dispersed into a plurality of dynamic stages, solid-liquid separation and blocking effects are considered, and the load of each stage is finely calculated; establishing a finite element model for multi-stage nonlinear analysis to obtain a structure response peak value; and performing double verification on the strength of the component and the performance of the energy dissipater, and iteratively optimizing the design scheme. According to the method, the spanning from experience design to theoretical and refined design is realized, and the scientificity, the safety and the economical efficiency of the design of the single protective net are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of geological disaster prevention and control engineering technology, specifically to a design method for a flexible debris flow protection net based on the synergy of energy matching and force balance. Background Technology

[0002] With the rapid advancement of infrastructure construction in western my country, coupled with the increasing frequency of extreme weather events caused by global climate change, the risk of debris flow geological disasters has significantly intensified, creating an urgent need for efficient and reliable debris flow barrier structures.

[0003] Flexible debris flow protection netting, as a novel active prevention structure, mainly consists of interception units (flexible metal mesh), support structures (steel wire rope systems), energy-dissipating units (such as pressure-reducing rings), and connecting components. This structure effectively reduces peak impact loads through flexible large deformation and inherent solid-liquid separation (water filtration and sedimentation) effects. With its high structural efficiency, excellent economic performance, and convenient installation, it demonstrates great potential in addressing debris flow disasters characterized by high flow velocity, large boulders, and strong impacts in the rugged mountainous regions of western China.

[0004] Currently, relevant domestic engineering technical specifications mainly focus on rigid structures such as gravity dams and grid dams, and have not systematically provided specific design methods for flexible debris flow protection net structures. This leads to current related engineering applications relying heavily on engineering experience, exhibiting strong subjectivity and arbitrariness. To promote the standardization of this technology, some research has emerged that attempts to provide design methods. For example, Chinese invention patent CN109183705A discloses a "design method for segmented interception of flexible debris flow protection systems." This method mainly includes: determining the channel size and target interception volume based on hydrological data, and calculating the required number and spacing of the protection nets accordingly; simplifying the load acting on a single protection net into a static resultant force composed of debris flow impact force, accumulated weight component, and channel friction force; and then establishing a finite element model for stress analysis and verifying the strength of the components.

[0005] However, this existing technical method still has the following limitations: First, its core focus is on the macroscopic layout of multiple protective nets in the trench (the number and spacing of segmented interceptions), while the detailed and theoretical design of the single protective net structure itself, especially the energy dissipator as a key energy-consuming component, lacks scientific guidance in its design and selection. It only mentions "considering setting it if necessary," failing to establish a quantitative design chain from impact energy to energy consumption requirements to energy dissipation device selection. Second, in terms of load calculation, this method simplifies the complex and dynamic debris flow impact-deposition process into a static resultant force, ignoring the stages of the impact process, the time-varying characteristics of the load, and the load reduction effect of the solid-liquid separation effect of the protective net, making it difficult to accurately simulate the mechanical response of the structure during a real impact process. Finally, its design process lacks a dedicated verification step for the performance of the energy dissipator, failing to ensure the coordinated work and safety reserves between the energy dissipation unit and the main load-bearing components.

[0006] Therefore, current technologies still lack a systematic approach for the refined and dynamic design of flexible debris flow protection nets, based on the essence of energy transfer and dissipation. Insufficient depth in design theory makes it difficult to scientifically guarantee the rationality, coordination, and overall reliability of the net structure's internal components (especially energy dissipators) under extreme disasters, thus hindering further optimization and safe application of this advanced technology. Developing a design method that integrates energy matching and dynamic force balance to achieve a leap from empirical design to theoretical and refined design has significant practical engineering implications and technological innovation value. Summary of the Invention

[0007] To address the lack of refined design methods based on energy analysis in existing technologies, and the oversimplification of load models that fail to reflect the entire dynamic impact process of debris flows, this invention aims to provide a design method for flexible debris flow protection nets based on the synergy of energy matching and force balance. This method combines the scientific matching of energy dissipation with multi-stage dynamic mechanical analysis, forming a complete closed-loop process from preliminary design to detailed verification. It aims to fundamentally improve the scientific rigor, safety, and economy of single-layer protection net structure design.

[0008] To solve the above-mentioned technical problems, the technical solution proposed in this application is as follows: This invention provides a design method for flexible debris flow protection nets based on the synergy of energy matching and force balance, comprising the following steps: S1: Based on hydrological survey data, determine the layout location of the flexible debris flow protection net, the cross-sectional dimensions of the trench, and the debris flow design parameters. Based on the principle of energy matching, conduct a preliminary design of the protection net structure and complete the selection of energy dissipators and support ropes. S2: The process of debris flow acting on the protective net is divided into the initial impact stage, multiple siltation stages and the overflow stage. Based on the debris flow depth and the height of the protective net, the total number of impact stages required to divide the siltation stage into multiple load stages is determined. S3: Determine the loads acting on the protective net structure at each stage. Based on the total number of impact stages determined in S2, calculate the number of siltation stages and calculate the impact pressure of debris flow and the lateral pressure generated by the deposited debris flow on the flexible protective net at different siltation stages. S4: Establish a finite element model of the protective net structure, apply the loads determined in S3 to the model in stages for multi-stage nonlinear calculation, and obtain the peak values ​​of internal forces, deformations and energy dissipators elongation of each component. S5: Verify based on the calculation results of S4: Verify whether the peak internal force of each support rope and mesh meets its bearing capacity requirements, and verify whether the peak elongation of each energy dissipator meets its working performance requirements; if any verification fails to meet the requirements, return to S1 to adjust the preliminary design scheme.

[0009] Furthermore, the preliminary design of the protective net structure based on the energy matching principle described in S1 includes: S11: Determine the geometric dimensions of the protective netting based on the cross-sectional dimensions of the trench; S12: Calculate the debris flow impact energy based on the debris flow design parameters, and determine the energy consumption requirements of the energy dissipators connected to each support rope; S13: Select each energy consuming device according to the principle that the energy consumption capacity is not lower than the energy consumption demand, and determine the maximum working pull force of the selected energy consuming device; S14: Select each support rope according to the principle that the breaking force of the wire rope is greater than the maximum working tension of the connected energy consumer and taking into account the safety factor λ.

[0010] Furthermore, the specific steps in S1 include: S11: Based on the trench cross-sectional dimensions at the location where the flexible debris flow protection net is to be installed, determine the geometric dimensions of the flexible debris flow protection net, including the bottom width A. b Top width B b Height H b This ensures that the mesh size matches the trench size at the installation location, and the initial selection of mesh specifications is completed accordingly. S12: The debris flow design parameters include debris flow volume V, debris flow density ρ, debris flow impact velocity v0, flow depth h, and internal friction angle φ. The debris flow impact energy is calculated based on these parameters. E t The calculation formula is: ; S13: Based on the energy matching principle, determine the energy consumption requirements E1, E2, E3, and E4 of the energy consumers connected to the upper support rope, middle support rope, lower support rope, and side support rope. The calculation formulas are as follows:

[0011]

[0012]

[0013]

[0014] Wherein, k1, k2, k3, and k4 are the energy consumption ratio coefficients of the energy-consuming devices connected to the upper support rope, middle support rope, lower support rope, and side support rope, respectively. Based on the principle that the energy consumption capacity is not lower than the energy consumption demand, each energy consuming device is selected, and the maximum working pull force of each selected energy consuming device is determined. F ed1 , F ed2 , F ed3 , F ed4 ; S14: Based on the breaking force of the wire rope F rope Greater than the maximum working pull of the connected energy dissipator F ed And taking into account the principle of safety factor λ, that is Select and match various support ropes.

[0015] Furthermore, in S2, the formula for calculating the total number of impact stages n is: ,in H b h represents the height of the protective netting, and h represents the depth of the debris flow; the number of siltation stages. i ∈[2, n].

[0016] Furthermore, in S3, the debris flow impact force during the initial impact stage... The calculation formula is: , where α is the dynamic coefficient and β is the filtration effect coefficient.

[0017] Furthermore, in S3, during the siltation stage, the first... i Stage of debris flow impact pressure Lateral pressure generated by deposited debris flows The calculation formulas are as follows:

[0018]

[0019]

[0020]

[0021] in The number of siltation stages is i The velocity of the debris flow at that time; c The coefficient for the evolution of the blocking effect is recommended to be between 0.7 and 1.0. K The lateral pressure coefficient can be taken as 0.5; g It is the acceleration due to gravity; H i This represents the depth of the deposited debris flow.

[0022] Furthermore, in S3, the loads during the overflow stage include: Maximum lateral pressure generated by deposited debris flow The drag force τ generated by the subsequent flow overflowing from the top is calculated using the following formula:

[0023]

[0024] Furthermore, in S4, when establishing the finite element model, the mesh is simulated using beam elements, the support rope is simulated using cable elements, the connection between the mesh and the support rope is simulated using a sliding boundary, and the energy dissipator is simulated using elastoplastic spring elements.

[0025] Furthermore, in S5, the verification is accomplished by comparing the peak internal force of each component obtained in S4 with its bearing capacity, and comparing the peak elongation of each energy consumer with its allowable elongation; when the peak internal force of the support rope increases sharply, it is determined that the energy consumer connected to it has reached its maximum elongation.

[0026] Furthermore, in S5, the adjustment of the preliminary design scheme includes at least one of the following: adjusting the energy consumption device configuration, increasing the number of intermediate support ropes, increasing the rope specifications, and selecting higher strength materials.

[0027] On the other hand, this application also claims protection for an electronic device, comprising: processor; Memory, used to store one or more programs; When the processor executes one or more programs, it enables the processor to implement the design method for flexible debris flow protection nets based on the coordination of energy matching and force balance as described in any of the preceding claims.

[0028] Compared with the prior art, the present invention achieves the following beneficial technical effects: This invention proposes for the first time a design framework that coordinates energy matching and multi-stage dynamic force balance, enabling the design of flexible debris flow protection nets to move from experience to theory. By discretizing the impact process into multiple stages and introducing key effect coefficients, the realism and accuracy of load simulation are significantly improved; the scientific quantitative configuration of energy-consuming components and the collaborative design of the support system are realized; and a complete closed loop of "design-verification-optimization" is ultimately formed, achieving optimized design with economical materials while ensuring structural safety and reliability. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart illustrating the design process of a flexible debris flow protection net design method based on the synergy of energy matching and force balance, as described in this application. Figure 2 This is a load diagram illustrating the design method for a flexible debris flow protection net based on the synergy of energy matching and force balance in an embodiment of this application. Figure 3 This is a plan view of a flexible debris flow protection net based on the design method of energy matching and force balance in an embodiment of this application. Figure 4 This is a finite element model of a debris flow protection net based on the design method of flexible debris flow protection net based on energy matching and force balance in the embodiments of this application; Figure 5 This is a deformation diagram of the finite element model of the debris flow protection net based on the design method of flexible debris flow protection net based on energy matching and force balance in the embodiments of this application; Figure 6 This is a design analysis diagram of a flexible debris flow protection net structure design method based on the synergy of energy matching and force balance, as described in an embodiment of this application.

[0031] In the diagram: 1. Upper support rope; 2. Middle support rope; 3. Lower support rope; 4. Side support rope; 5. Netting; 6. Energy dissipator; 7. Anchor point. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] See Figure 3 The flexible debris flow protection net structure targeted by the method of this invention mainly includes: an upper support rope 1, a middle support rope 2, a lower support rope 3, a side support rope 4, a mesh panel 5, an energy dissipator 6, and anchor points 7. The energy dissipator 6 is connected to the upper support rope 1, the middle support rope 2, the lower support rope 3, and the side support rope 4 respectively. The ends of each support rope are ultimately anchored to a stable foundation (ground or mountain) through the anchor points 7. The mesh panel 5 is connected to each support rope through connectors, forming the main flexible interception surface.

[0034] like Figure 1 As shown, this application discloses a design method for a flexible debris flow protection net structure based on the synergy of energy matching and force balance, which includes the following steps: S1: Based on hydrological survey data, determine the layout location of the flexible debris flow protection net, the cross-sectional dimensions of the trench, and the debris flow design parameters. Based on the principle of energy matching, conduct a preliminary design of the protection net structure and complete the selection of energy dissipators and support ropes.

[0035] 1. Based on hydrological survey data, determine the locations for deploying flexible debris flow protection nets and the cross-sectional dimensions (bottom width) of the trenches at those locations. A c Top width B c ,depth H c ), and debris flow characteristics (volume) V ,density r ,speed v 0. Flow depth h、 internal friction angle f wait); 2. Preliminary design of a flexible debris flow protection net structure based on energy matching; Based on the trench cross-sectional dimensions at the location where the flexible debris flow protection net is to be installed, determine the geometric dimensions (bottom width) of the flexible debris flow protection net. A b Top width B b ,high H b The mesh size is generally equivalent to the size of the trench at the installation location, and the initial selection of mesh specifications is completed accordingly.

[0036] Calculate the impact energy of debris flow based on its characteristics. E t :

[0037] Based on the principle of energy matching, the energy consumption ratio coefficients of the energy consumers connected to the upper support rope, middle support rope, lower support rope, and side support rope are clearly defined. k 1. k 2. k 3. k 4. This clarifies the energy consumption requirements of the energy consumers connected to the upper, middle, lower, and side support ropes. E 1. E 2. E 3. E 4:

[0038]

[0039]

[0040]

[0041] Energy consumption ratio of the upper support rope energy dissipator k 1. A recommended value is 5%~8%, which is the energy consumption ratio coefficient of the middle support rope energy dissipator. k 2. A value of 5% to 20% is recommended for the energy consumption ratio of the lower support rope energy dissipator. k 3. A value of 5% to 10% is recommended for the energy consumption ratio of the side support rope energy dissipator. k 4. It is recommended that the value be between 3% and 5%.

[0042] Based on this, and adhering to the principle that the energy consumption capacity should not be lower than the energy consumption demand, energy consumers are selected from the existing energy consumer database, thereby determining the maximum working pull of the selected energy consumer. F ed Therefore, the connecting wire rope is selected based on the breaking force of the wire rope being greater than the maximum working tensile force of the energy dissipator, while also considering a certain safety factor. l :

[0043] Safety factor of wire rope l It is recommended that the value be no less than 2.0.

[0044] S2: The process of debris flow acting on the protective net is divided into the initial impact stage, multiple siltation stages, and overflow stage. Based on the debris flow depth and the height of the protective net, the total number of impact stages required to divide the siltation stage into multiple load stages is determined.

[0045] Based on the debris flow depth in step S1 h and the height of the flexible protective net for debris flow H b Determine the total number of impact phases n :

[0046] S3: Determine the loads acting on the protective net structure at each stage. Based on the total number of impact stages determined in S2, calculate the number of siltation stages, and calculate the impact pressure of debris flow and the lateral pressure generated by the deposited debris flow on the flexible protective net at different siltation stages.

[0047] Determine the loads acting on the flexible debris flow protection net structure at each stage; In the initial impact phase, the flexible debris flow protection net mainly bears the impact force of the debris flow. :

[0048] Power coefficient α It is recommended to use a value of 0.7 to 2.0 based on the debris flow density; filtration effect coefficient β It is recommended to use 0.5~1.0 based on the debris flow density.

[0049] Number of siltation stages i(i) ∈[2, n Flexible debris flow protection nets can withstand the impact pressure of debris flows. Lateral pressure generated by deposited debris flows :

[0050]

[0051]

[0052]

[0053] Number of siltation stages i The velocity of the debris flow; c The coefficient for the evolution of the blocking effect is recommended to be between 0.7 and 1.0. K The lateral pressure coefficient can be taken as 0.5; g It is the acceleration due to gravity; H i This represents the depth of the deposited debris flow.

[0054] During the overflow stage, the flexible protective netting for debris flows withstands the lateral pressure generated by the deposited debris flows. The drag force generated by the subsequent flow overflowing from the top. t :

[0055]

[0056] S4: Establish a finite element model of the protective net structure, apply the loads determined in S3 to the model in stages for multi-stage nonlinear calculation, and obtain the peak values ​​of internal forces, deformations and energy dissipators elongation of each component. Based on the dimensions and component configuration of the flexible debris flow protection net determined in step S1, a finite element calculation model is established. The loads acting on the flexible debris flow protection net structure at each stage as specified in step S3 are applied to the finite element model in stages. Multi-stage nonlinear calculations are performed until the load application is completed, and the internal forces, deformations, and elongations of the energy dissipators of each component in the structure are obtained, and their peak values ​​are determined. S5: Verify based on the calculation results of S4: Verify whether the peak internal force of each support rope and mesh meets its bearing capacity requirements, and verify whether the peak elongation of each energy dissipator meets its working performance requirements; if any verification fails to meet the requirements, return to S1 to adjust the preliminary design scheme.

[0057] Extract the peak internal force of each component and verify the bearing capacity of the upper support rope 1, middle support rope 2, lower support rope 3, side support rope 4, and mesh 5; extract the elongation of the energy dissipator and verify the energy dissipator 6; if the component strength or the elongation of the energy dissipator cannot meet the requirements, return to step S1 and adjust the preliminary design scheme. S6: Design the connection nodes and anchor points of the flexible debris flow protection net structure.

[0058] Furthermore, the total energy consumption of the energy dissipators in the debris flow flexible protection net is less than the impact kinetic energy of the debris flow, and the proportion is usually less than 30%.

[0059] Furthermore, in the finite element model, the mesh 5 can be simulated using beam elements, and the support rope can be simulated using cable elements; the mesh ring 5 and the upper support rope 1, middle support rope 2, lower support rope 3, and side support rope 4 can be simulated using sliding boundaries to ensure that the mesh can slide along the rope when under force; the energy dissipator 6 can be simulated using an elastoplastic spring.

[0060] Furthermore, the proposed adjustments to the preliminary design include adjusting the energy dissipator configuration, increasing the number of intermediate support ropes, increasing rope specifications, and selecting higher strength materials.

[0061] See Figure 2-6 The following section, using a specific debris flow disaster site as an example, details the process of designing a flexible debris flow protection net based on the synergy of energy matching and force balance, as described in this invention: (1) Based on hydrogeological survey data, the bottom width of the trench cross-section at the location where the flexible debris flow protection net is laid is...A c Top width B c ,depth H c The lengths of the debris flow protection nets are 2.92m, 6.85m, and 2.48m respectively, representing the volume of debris flows intercepted. V 100m 3 Debris flow density r ,speed v 0. Flow depth h、 internal friction angle f 1500 kg / m 3 6 m / s, 0.5 m and 12°; (2) Preliminary design of flexible debris flow protection net structure based on energy matching; Based on the trench cross-sectional dimensions at the location where the flexible debris flow protection net is to be installed, determine the bottom width of the flexible debris flow protection net. A b Top width B b ,high H b The sizes are 3m, 7m, and 2.5m respectively, and the initial mesh size is RN / 9 / 3 / 300.

[0062] Calculate the debris flow impact energy based on the debris flow characteristics described in step one. E t :

[0063] Determine the energy consumption ratio of the energy consumers connected to the upper, middle, lower, and side support ropes. k 1. k 2. k 3. k The percentages 4 are 6%, 10%, 8%, and 4%, respectively, thus clearly defining the energy consumption requirements of the energy consumers connected to the upper, middle, lower, and side support ropes. E 1. E 2. E 3. E 4分别为 :

[0064]

[0065]

[0066]

[0067] The GS8002 pressure reducing ring is selected as the energy dissipator. The maximum working tensile force of a single pressure reducing ring is 60kN, and the energy dissipation capacity is 55kJ. Based on the principle that the energy dissipation capacity should not be lower than the energy dissipation demand, the energy dissipators for the upper support rope, middle support rope, lower support rope, and side support rope are configured as B2C2, B3C2, B2C2, and C2 respectively (B: series, C: parallel). Therefore, the maximum working tensile force of the energy dissipator group for the upper support rope, middle support rope, lower support rope, and side support rope can be determined. F ed The strengths are 120kN, 180kN, 120kN, and 60kN, respectively, with a maximum elongation of 1m for each. Based on this, the specifications of the selected upper support rope, middle support rope, lower support rope, and side support rope are 1φ22, 2φ20, 1φ22, and 1φ16, respectively, with breaking forces of 304kN, 504kN, 304kN, and 161kN, and a safety factor of [missing information]. l The values ​​are 2.5, 2.8, 2.5 and 2.7 respectively.

[0068] (3) Based on the debris flow depth in step one h The height of the flexible debris flow protection net in step two H b Determine the total number of impact phases n :

[0069] (4) Determine the loads acting on the flexible debris flow protection net structure at each stage; In the initial impact phase, the dynamic coefficient α Take 1.5; filtration effect coefficient β Taking 0.8, the main debris flow impact pressure that the flexible debris flow protection net can withstand is... :

[0070] Number of siltation stages i ( i (∈[2, 5]) Flexible debris flow protection netting withstands the impact pressure of debris flows. Lateral pressure generated by deposited debris flows Evolution coefficient of blocking effect c The value is 0.8, and the lateral pressure coefficient is... K Taking 0.5, the stage's impact force All are:

[0071] Number of siltation stages i The lateral pressures corresponding to values ​​2, 3, 4, and 5 are as follows:

[0072]

[0073]

[0074]

[0075] During the overflow stage, the flexible protective netting for debris flows withstands the lateral pressure generated by the deposited debris flows. The drag force generated by the subsequent flow overflowing from the top. t :

[0076]

[0077] (5) Establish a calculation model and perform force analysis; In the embodiments of this application, a finite element model of the flexible debris flow protection net was established using the general-purpose finite element software LS-DYNA, and calculation analysis was performed. The net rings were simulated using beam elements, with each ring divided into 16 elements. The rings were connected by a nesting mechanism, and a contact algorithm was used to achieve force transfer and contact slip between the rings. The energy dissipator was simulated using elastoplastic spring elements, and the wire rope was simulated using cable elements. A guided slip contact method was used between the wire rope and the net rings. The loads of each stage were applied evenly to the nodes within the corresponding height range in stages, with each stage lasting 0.5 seconds. The time-history changes of the internal forces, deformations, and displacements of each component in the structure were recorded and analyzed, and their peak values ​​were determined.

[0078] The types of finite element software are not limited to the specific implementation methods described above, and those skilled in the art can select according to their needs.

[0079] (6) Verify the load-bearing capacity of each component of the debris flow flexible protection net; Extract the peak internal forces of each component and verify the bearing capacity of the upper support rope 1, middle support rope 2, lower support rope 3, side support rope 4, and mesh 5; extract the elongation of the energy dissipator and verify the energy dissipator 6.

[0080]

[0081] (7) Design the connection nodes and anchor points of the flexible debris flow protection net structure.

[0082] The structural design includes the connection between the steel profile of the anchor bolt and the upper and lower support ropes, and the connection between the wire rope and the anchor bolt.

[0083] This application also provides an electronic device for implementing the above method, comprising: At least one processor; and A memory that is communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method.

[0084] The electronic device may include one or more processors, memory, and transmission devices, and the terminal may also include input / output devices.

[0085] Those skilled in the art will understand that the terminal can be a smartphone (such as an Android phone, an iOS phone, etc.), a tablet computer, a PDA, a mobile internet device (MID), a PAD, and other terminal devices.

[0086] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing the hardware related to the terminal device. This program can be stored in a computer-readable storage medium, which may include: a flash drive, read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk, etc. The storage medium stores a computer program that, when executed by a processor, implements the steps of the methods described above.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for flexible debris flow protection nets based on the synergy of energy matching and force balance, characterized in that, Includes the following steps: S1: Based on hydrological survey data, determine the layout location of the flexible debris flow protection net, the cross-sectional dimensions of the trench, and the debris flow design parameters. Based on the principle of energy matching, conduct a preliminary design of the protection net structure and complete the selection of energy dissipators and support ropes. S2: The process of debris flow acting on the protective net is divided into the initial impact stage, multiple siltation stages and the overflow stage. Based on the debris flow depth and the height of the protective net, the total number of impact stages required to divide the siltation stage into multiple load stages is determined. S3: Determine the loads acting on the protective net structure at each stage. Based on the total number of impact stages determined in S2, calculate the number of siltation stages and calculate the impact pressure of debris flow and the lateral pressure generated by the deposited debris flow on the flexible protective net at different siltation stages. S4: Establish a finite element model of the protective net structure, apply the loads determined in S3 to the model in stages for multi-stage nonlinear calculation, and obtain the peak values ​​of internal forces, deformations and energy dissipators elongation of each component. S5: Verify based on the calculation results of S4: Verify whether the peak internal force of each support rope and mesh meets its bearing capacity requirements, and verify whether the peak elongation of each energy dissipator meets its working performance requirements; if any verification fails to meet the requirements, return to S1 to adjust the preliminary design scheme.

2. The method according to claim 1, characterized in that, The preliminary design of the protective net structure based on the energy matching principle described in S1 includes: S11: Determine the geometric dimensions of the protective netting based on the cross-sectional dimensions of the trench; S12: Calculate the debris flow impact energy based on the debris flow design parameters, and determine the energy consumption requirements of the energy dissipators connected to each support rope; S13: Select each energy consuming device according to the principle that the energy consumption capacity is not lower than the energy consumption demand, and determine the maximum working pull force of the selected energy consuming device; S14: Select each support rope according to the principle that the breaking force of the wire rope is greater than the maximum working tension of the connected energy consumer and taking into account the safety factor λ.

3. The method according to claim 2, characterized in that, The specific steps in S1 include: S11: Based on the trench cross-sectional dimensions at the location where the flexible debris flow protection net is to be installed, determine the geometric dimensions of the flexible debris flow protection net, including the bottom width A. b Top width B b Height H b This ensures that the mesh size matches the trench size at the installation location, and the initial selection of mesh specifications is completed accordingly. S12: The debris flow design parameters include debris flow volume V, debris flow density ρ, debris flow impact velocity v0, flow depth h, and internal friction angle φ. The debris flow impact energy is calculated based on these parameters. E t The calculation formula is: ; S13: Based on the energy matching principle, determine the energy consumption requirements of the energy consumers connected to the upper support rope, middle support rope, lower support rope, and side support rope. , , , The calculation formulas are as follows: Wherein, k1, k2, k3, and k4 are the energy consumption ratio coefficients of the energy-consuming devices connected to the upper support rope, middle support rope, lower support rope, and side support rope, respectively. Based on the principle that the energy consumption capacity is not lower than the energy consumption demand, each energy consuming device is selected, and the maximum working pull force of each selected energy consuming device is determined. F ed1 , F ed2 , F ed3 , F ed4 ; S14: Based on the breaking force of the wire rope F rope Greater than the maximum working pull of the connected energy dissipator F ed And taking into account the principle of safety factor λ, that is Select and match various support ropes.

4. The method according to claim 1, characterized in that, In S2, the formula for calculating the total number of impact stages n is: ,in H b h represents the height of the protective netting, and h represents the depth of the debris flow; the number of siltation stages. i ∈[2, n].

5. The method according to claim 1, characterized in that, In S3, the debris flow impact force during the initial impact stage The calculation formula is: , where α is the dynamic coefficient and β is the filtration effect coefficient.

6. The method according to claim 1, characterized in that, In S3, during the siltation stage, the first i Stage of debris flow impact pressure Lateral pressure generated by deposited debris flows The calculation formulas are as follows: in The number of siltation stages is i The velocity of the debris flow at that time; γ The coefficient for the evolution of the blocking effect is recommended to be between 0.7 and 1.

0. K The lateral pressure coefficient can be taken as 0.5; g It is the acceleration due to gravity; H i This represents the depth of the deposited debris flow.

7. The method according to claim 1, characterized in that, In S3, the loads during the overflow stage include: Maximum lateral pressure generated by deposited debris flow The drag force τ generated by the subsequent flow overflowing from the top is calculated using the following formula:

8. The method according to claim 1, characterized in that, In S4, when establishing the finite element model, the mesh is simulated using beam elements, the support rope is simulated using cable elements, the connection between the mesh and the support rope is simulated using a sliding boundary, and the energy dissipator is simulated using elastoplastic spring elements.

9. The method according to claim 1, characterized in that, In S5, the verification is completed by comparing the peak internal force of each component obtained in S4 with its bearing capacity, and comparing the peak elongation of each energy consumer with its allowable elongation; when the peak internal force of the support rope increases sharply, it is determined that the energy consumer connected to it has reached its maximum elongation.

10. The method according to claim 1, characterized in that, In S5, the adjustment of the preliminary design scheme includes at least one of the following: adjusting the energy consumption device configuration, increasing the number of intermediate support ropes, increasing the rope specifications, and selecting higher strength materials.

11. An electronic device, characterized in that, include: processor; Memory, used to store one or more programs; When the processor executes the one or more programs, it causes the processor to implement the design method for flexible debris flow protection nets based on energy matching and force balance as described in any one of claims 1-10.

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