Tetrahedron structure and debris flow bulk density decay rate prediction method, model construction method and regulation method

Abstract

The application provides a tetrahedron structure and a debris flow volume and density decay rate prediction method, a model construction method and a regulation method, and relates to the technical field of debris flow control. The tetrahedron structure is a regular tetrahedron solid structure, a regular tetrahedron solid frame structure or a regular tetrahedron solid sphere branch structure. The debris flow volume and density decay rate prediction method is calculated through a prediction model. The model construction method is obtained by analyzing the regulation factors of the tetrahedron structure on the volume and density of the debris flow by using the dimensional analysis method. The volume and density regulation method adjusts and optimizes the best throwing interval and arrangement mode of the tetrahedron structure based on the prediction results of the debris flow volume and density decay rate, and then throws the corresponding tetrahedron structure in the target channel by using the numerical simulation method or the debris flow dam break simulation experiment device. The application is flexible in arrangement, can effectively regulate the volume and density of the debris flow, enriches the measures and technical means for regulating the volume and density of the debris flow, and provides key parameter support and technical support for the prevention and control work.

Description

Technical Field

[0001] This invention relates to the field of debris flow control technology, and in particular to a tetrahedral structure and a method for predicting the bulk density decay rate of debris flows, a model construction method, and a control method. Background Technology

[0002] As a typical high-intensity natural disaster arising from mountainous environments, debris flows are characterized by high energy density, short duration of impact, and wide spatial influence. The density of a debris flow refers to the mass of the debris flow fluid per unit volume. It is a core physical parameter describing the solid content in a debris flow, directly reflecting its consistency, fluid properties, and destructive intensity. Existing research indicates that the debris flow disaster mechanism is influenced by multiple factors, with the density of the debris flow being one of the core indicators.

[0003] Currently, the active control technology system for debris flow bulk density is still weak, and existing technologies are relatively limited and suffer from functional homogeneity. Typical application examples include: barrier facilities using beam-type grid structures can play a certain role in bulk density regulation, but their main function is to block coarse debris and drain fine debris, and they are easily damaged by high-bulk debris flows; composite drainage systems integrating stepped landforms and stilling pier components can achieve spatial reconstruction of fluid density through stepped energy dissipation structures set along the flow path, specifically reducing the debris flow density in upstream and downstream sections while strengthening the density distribution characteristics in the central region, but their layout is relatively fixed and lacks flexibility; biomimetic fishback-shaped water-rock separation structures can regulate debris flow bulk density. After debris flows of different bulk densities pass through the structure, the bulk density of the debris flows all show a decreasing trend, with an average reduction of up to 13.4%, but high solids concentration debris flows may cause fine particles to accumulate in the grid gaps, reducing the efficiency of subsequent structures. Summary of the Invention

[0004] This invention aims to provide a tetrahedral structure and a method for predicting the bulk density decay rate of debris flows, a model construction method, and a control method. The arrangement is flexible and can effectively control the bulk density of debris flows, enriching the measures and technical means for controlling the bulk density of debris flows, and providing key parameter support and technical guarantee for prevention and control work.

[0005] The technical solution adopted in this invention is:

[0006] A tetrahedral structure for controlling the bulk density of debris flows is a regular tetrahedral solid structure with a minimum edge length of: and The larger value in; where u c The initial flow velocity of the tetrahedral structure is expressed in m / s and is determined based on the flow velocity of the debris flow; k represents an empirical coefficient, ranging from 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³.3 ;γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

[0007] A method for predicting the bulk density decay rate of debris flows, used to estimate and evaluate the effectiveness of tetrahedral structures for bulk density control in debris flows as described above, includes the following steps:

[0008] Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements.

[0009] Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ;

[0010] Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m). 3 ;

[0011] Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m).

[0012] Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers;

[0013] Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r1 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r1 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation.

[0014] A tetrahedral structure for controlling the bulk density of debris flows is a regular tetrahedral solid frame structure composed of four identical solid columns. One end of each column is connected to a common point, and the remaining ends spatially form the four vertices of the regular tetrahedron. The minimum length of each solid column is: and The larger of the values, and the diameter of the circumcircle of the cross-section of the solid prism is 0.15 to 0.35 times its length; where u c The initial flow velocity of the tetrahedral structure is expressed in m / s and is determined based on the flow velocity of the debris flow; k represents an empirical coefficient, ranging from 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³. 3 ;γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

[0015] Furthermore, the solid cylinder is a cylinder or a prism.

[0016] A method for predicting the bulk density decay rate of debris flows, used to estimate and evaluate the effectiveness of tetrahedral structures for bulk density control in debris flows as described above, includes the following steps:

[0017] Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements.

[0018] Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ;

[0019] Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c， Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m). 3 ;

[0020] Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m).

[0021] Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers;

[0022] Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r2 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r2 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation.

[0023] A tetrahedral structure for controlling the bulk density of debris flows is a branched structure of a solid tetrahedral sphere, consisting of a solid sphere, four identical solid, thick, long cylinders, and thirty-six identical solid, thin, short cylinders. One end of each of the four identical solid, thick, long cylinders is fixed to a corresponding position on the solid sphere, and the remaining end forms the four vertices of the tetrahedron in space. The thirty-six solid, thin, short cylinders are divided into four large groups, each of which is further divided into three smaller groups. Each smaller group includes three solid, thin, short cylinders, one end of which is fixed to the solid, thick, long cylinder, and the other end forms the three vertices of the tetrahedron in space. The minimum diameter of the solid sphere is [missing information]. and The larger of the values; the minimum length of a solid, thick, long cylinder is: and The larger of the values, and the diameter of the circumcircle of the cross-section of a solid, thick, long prism is 0.2 to 0.4 times its length; the minimum length of a solid, thin, short prism is: and The larger of the values, and the circumcircle diameter of the cross-section of the solid, slender prism is 0.4 to 0.6 times its length; where u c The initial flow velocity of the tetrahedral structure is expressed in m / s and is determined based on the flow velocity of the debris flow; k represents an empirical coefficient, ranging from 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³. 3 γs represents the bulk density of the tetrahedral structure, in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

[0024] Furthermore, the solid, thick, elongated cylinder is a cylinder or a prism;

[0025] And / or, the solid, slender cylinder is a cylinder or a prism.

[0026] A method for predicting the bulk density decay rate of debris flows, used to estimate and evaluate the effectiveness of tetrahedral structures for bulk density control in debris flows as described above, includes the following steps:

[0027] Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements.

[0028] Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ;

[0029] Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c， Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m). 3 ;

[0030] Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m).

[0031] Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers;

[0032] Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r3 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r3 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation.

[0033] A method for constructing a debris flow unit weight decay rate prediction model to obtain the prediction model used in the aforementioned debris flow unit weight decay rate prediction method includes the following steps:

[0034] Step S1: Conduct a physical simulation experiment of debris flow movement in a flume under multiple working conditions to obtain the factors affecting the control of the tetrahedral structure on the bulk density of the debris flow. The control factors include: characteristic dimensions of the tetrahedral structure, channel conditions, debris flow properties before tetrahedral structure control, and debris flow movement state before tetrahedral structure control. The characteristic dimensions of the tetrahedral structure include: edge length L of a solid tetrahedral structure, virtual edge length L of a solid tetrahedral frame structure, or virtual edge length L of a solid tetrahedral sphere branch structure, effective height H, and volume V. t The quantity N; the channel conditions include: the longitudinal slope θ of the channel; the debris flow properties before the tetrahedral structure regulation include: the unit weight γ of the mixture. c Total volume V c Characteristic particle size d of soil particles r The tetrahedral structure was used to regulate the debris flow motion state before the flow velocity v0 and the mud depth h0.

[0035] Step S2: Dimensional analysis is used to analyze the control factors and create a predictive model for the control of debris flow bulk density by tetrahedral structure.

[0036] A method for controlling the unit weight of debris flows includes the following steps:

[0037] Step S1: Use the debris flow bulk density decay rate prediction method as described above to obtain the number N of the optimal tetrahedral structures corresponding to the tetrahedral structures.

[0038] Step S2: Using numerical simulation or debris flow dam failure simulation experimental device, set simulation conditions based on the relevant parameters collected in the debris flow bulk density decay rate prediction method mentioned above. At the same time, apply the N tetrahedral structures obtained in step S1, and adjust and optimize to obtain the optimal throwing spacing and arrangement of the tetrahedral structures.

[0039] Step S3: Based on the best simulation results obtained in step S2, the corresponding tetrahedral structure is launched into the target channel.

[0040] The beneficial effects of this invention are:

[0041] 1. This invention provides a tetrahedral structure that is flexible in arrangement, can effectively control the bulk density of debris flows, and prevents fine particles in debris flows from accumulating inside or between tetrahedral structures, resulting in a longer service life.

[0042] 2. This invention provides a method for predicting the density decay rate of debris flows, which is applicable to the refined assessment of the disaster risk of high-density debris flows and the design of prevention and control engineering schemes in mountainous debris flow gully scenarios. It overcomes the technical bottlenecks of the limitations and lack of flexibility in the application of traditional empirical methods in the dynamic control of debris flow density, and further enriches the measures and technical means for the control of debris flow density in mountainous areas of my country, providing key parameter support and technical guarantee for debris flow disaster prevention and control.

[0043] 3. This invention provides a method for constructing a debris flow bulk density reduction rate prediction model, which comprehensively considers core influencing factors such as the initial bulk density of the debris flow, the scale of the outbreak, the longitudinal slope of the channel, and the geometric morphology of the tetrahedral structure. It can achieve accurate quantitative prediction of the bulk density reduction rate of debris flows under different tetrahedral configurations.

[0044] 4. This invention provides a method for controlling the bulk density of debris flows. By controlling the bulk density of debris flows, it can serve as a key technical means to effectively prevent and mitigate disaster risks and significantly reduce their structural damage to protective structures, which has important engineering practical significance. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the tetrahedral structure used for debris flow density control in Example 1.

[0047] Figure 2 This is a schematic diagram of the tetrahedral structure used for debris flow density control in Example 2.

[0048] Figure 3 This is a schematic diagram of the tetrahedral structure used for debris flow density control in Example 3. Detailed Implementation

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.

[0051] The embodiments of the invention will now be described in detail with reference to the accompanying drawings.

[0052] Example 1

[0053] Figure 1 This is a schematic diagram of the tetrahedral structure used for debris flow density control in Example 1. Figure 1 As shown, the tetrahedral structure is a solid tetrahedron, made of concrete, reinforced concrete, or stainless steel. The minimum length of the edges of the tetrahedral structure is: and The larger value in; where u c The initial flow velocity of the tetrahedral structure is expressed in m / s and is determined based on the flow velocity of the debris flow; k represents an empirical coefficient, ranging from 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³. 3 ;γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

[0054] The tetrahedral structure in this embodiment is flexible in its arrangement, can effectively control the bulk density of debris flows, and fine particles in debris flows are not easily deposited inside or between the tetrahedral structures, resulting in a longer service life.

[0055] Example 2

[0056] Figure 2This is a schematic diagram of the tetrahedral structure used for debris flow density control in Example 2. Figure 2 As shown, the tetrahedral structure is a solid tetrahedral frame structure, mainly composed of four identical solid columns. The solid columns are made of concrete, reinforced concrete, or stainless steel, and are cylindrical or prismatic in shape. One end of each of the four solid columns is connected to a common point, which is also the centroid of the tetrahedron in terms of spatial arrangement. The remaining ends form the four vertices of the tetrahedron in terms of spatial arrangement. The minimum length of each solid column is: and The larger of the values, and the diameter of the circumcircle of the cross-section of the solid prism is 0.15 to 0.35 times its length; where u c The initial flow velocity of the tetrahedral structure is expressed in m / s and is determined based on the flow velocity of the debris flow; k represents an empirical coefficient, ranging from 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³. 3 ;γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

[0057] Example 3

[0058] Figure 3 This is a schematic diagram of the tetrahedral structure used for debris flow density control in Example 3. Figure 3 As shown, the tetrahedral structure is a regular tetrahedral solid sphere branch structure, mainly composed of a solid sphere, four identical solid thick and long prisms, and thirty-six identical solid thin and short prisms; the solid sphere, solid thick and long prisms, and solid thin and short prisms are made of concrete, reinforced concrete, or stainless steel, and the solid thick and long prisms and solid thin and short prisms are cylindrical or prismatic in shape. Four identical solid, thick, long cylinders are fixed at one end to corresponding positions on a solid sphere. The intersection of the four cylinders coincides with the center of gravity of the solid sphere, which is also the center of gravity of the tetrahedron in spatial arrangement. The remaining ends form the four vertices of the tetrahedron in space. Thirty-six solid, thin, short cylinders are divided into four large groups, each of which is further divided into three smaller groups. Each smaller group consists of three solid, thin, short cylinders, one end of which is fixed to a solid, thick, long cylinder, and the other end of which forms the three vertices of a tetrahedron in space. The minimum diameter of the solid sphere is... and The larger of the values; the minimum length of a solid, thick, long cylinder is: and The larger of the values, and the diameter of the circumcircle of the cross-section of a solid, thick, long prism is 0.2 to 0.4 times its length; the minimum length of a solid, thin, short prism is: and The larger of the values, and the circumcircle diameter of the cross-section of the solid, slender prism is 0.4 to 0.6 times its length; where u c The initial flow velocity of the tetrahedral structure is expressed in m / s and is determined based on the flow velocity of the debris flow; k represents an empirical coefficient, ranging from 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³. 3 ;γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

[0059] Example 4

[0060] This embodiment provides a method for constructing a debris flow bulk density decay rate prediction model, including the following steps:

[0061] Step S1: Conduct a physical simulation experiment of debris flow movement in a flume under multiple working conditions to obtain the factors affecting the control of the tetrahedral structure on the bulk density of the debris flow. The control factors include: characteristic dimensions of the tetrahedral structure, channel conditions, debris flow properties before tetrahedral structure control, and debris flow movement state before tetrahedral structure control. The characteristic dimensions of the tetrahedral structure include: edge length L of a solid tetrahedral structure, virtual edge length L of a solid tetrahedral frame structure, or virtual edge length L of a solid tetrahedral sphere branch structure, effective height H, and volume V. t The quantity N; the channel conditions include: the longitudinal slope θ of the channel; the debris flow properties before the tetrahedral structure regulation include: the unit weight γ of the mixture. c Total volume V c Characteristic particle size d of soil particles r The tetrahedral structure was used to regulate the debris flow motion state before the flow velocity v0 and the mud depth h0.

[0062] Step S2: Dimensional analysis is used to analyze the control factors and create a predictive model for the control of debris flow bulk density by tetrahedral structure.

[0063] In this embodiment, based on a combination of physical process analysis and empirical formulas, the regulation of debris flow bulk density by tetrahedral structures is a complex dynamic process influenced by multiple factors. This is not only reflected in the complexity of the debris flow movement itself, but also in the mutual coupling between the debris flow and the tetrahedral structure. By summarizing research findings on related applications of tetrahedral structures, the main factors influencing the regulation of debris flow by tetrahedral structures are analyzed as shown above. Based on the above analysis, the relationship between the regulation characteristics of debris flow by tetrahedral structures and the influencing factors can be expressed as a function, namely:

[0064] Formula 1

[0065] In the formula: and These are the characteristic parameters of debris flow controlled by tetrahedral structure and those controlled by tetrahedral structure, respectively. In this embodiment, the debris flow unit weight is used. This represents a functional relationship between these variables; L represents the edge length of a solid tetrahedron structure, the virtual edge length of a solid tetrahedron frame structure, or the virtual edge length of a branched solid tetrahedron sphere, in meters; H represents the effective height of the tetrahedron structure, in meters; V t The volume (space occupied) of a tetrahedral structure is expressed in meters (m). 3 N represents the number of tetrahedral structures; θ represents the longitudinal slope of the ditch; γ c V represents the bulk density of a debris flow mixture, expressed in kg / m³. c The volume of the debris flow is expressed in meters (m). 3 ;d r The characteristic particle size of the soil is represented in mm; v0 represents the debris flow velocity in m / s; and h0 represents the mud depth in m.

[0066] Because the independent variables on the right side of Formula 1 include three fundamental quantities with independent dimensions: time (T), length (L), and mass (M), according to dimensional analysis theory (… According to the theorem, 10 independent variables can be transformed into 5 dimensionless independent variables through dimensional analysis, that is:

[0067] Formula 2

[0068] In the formula: This represents 5 dimensionless independent variables.

[0069] By incorporating dimensionless numbers and experimental characteristic parameters from debris flow kinematics, it can be seen that Equation 1 can be written in the following form:

[0070]

[0071] Formula 3

[0072] In the formula: For a dimensionless dependent variable, use This indicates that the quantitative index characterizing the regulation characteristics is the bulk density decay rate of debris flow in this embodiment; V c The volume of the debris flow is expressed in meters (m). 3 N represents the number of tetrahedral structures; V t The volume of a tetrahedral structure is expressed in meters (m). 3 ;γ c This indicates the bulk density of the debris flow mixture, expressed in kg / m³. This is the specific gravity of water, taken as 1.0 kg / m³; The unit weight of the soil in the debris flow mixture is generally between 2.6 and 2.8 kg / m³, and 2.65 kg / m³ is used in this embodiment; v0 represents the debris flow velocity in m / s; h0 represents the mud depth in m; g is the acceleration due to gravity, taken as 9.8 m / s². 2 ; The relative scale of the debris flow represents the relationship between the tetrahedral structure and the scale of the debris flow. , These represent the soil volume concentration of the debris flow mixture before tetrahedral structure adjustment and the relative dimensions of the tetrahedral structure (L represents the edge length of a solid tetrahedral structure, the virtual edge length of a solid tetrahedral frame structure, or the virtual edge length of a solid tetrahedral sphere branch structure, in meters; d...). r The characteristic particle size of soil particles (in mm) represents the fluid properties of debris flows. The Froude number represents the motion state of debris flow before the tetrahedral structure regulates it. It is the tangent of the longitudinal slope of the ditch.

[0073] Based on the above analysis, and considering the mutually coupled relationship among the influencing factors, Equation 3 can be further written in the following parametric function form.

[0074]

[0075] Formula 4

[0076] In the formula: , , , , , The coefficients are undetermined. The optimal values ​​of each parameter can be determined through nonlinear regression analysis based on experimental data. The coefficients also differ for different quantitative indicators of control characteristics. θ represents the longitudinal slope of the ditch. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; The Froude number is represented; L represents the edge length of a solid tetrahedron, the virtual edge length of a solid tetrahedron frame structure, or the virtual edge length of a branched solid tetrahedron sphere, in meters (m); d r This indicates the characteristic particle size of the soil particles, in mm.

[0077] This embodiment does not consider the influence of the relative dimensions of the tetrahedral structure, i.e., the parameters under experimental conditions. Since is a constant, Equation 4 can be further written as:

[0078] Formula 5

[0079] Formula 6

[0080] In the formula: , , , , , The coefficients are undetermined. The optimal values ​​of each parameter can be determined through nonlinear regression analysis based on experimental data. The coefficients also differ for different quantitative indicators of control characteristics. θ represents the longitudinal slope of the ditch. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; The Froude number is represented by L; L represents the edge length of a tetrahedral structure, the length of a solid prism, or the length of a solid, thick prism, in meters (m); d r This indicates the characteristic particle size of the soil particles, in mm.

[0081] In this embodiment, the measured bulk density data of debris flow obtained from multiple sets of experiments (e.g., conducting 56 sets of experiments) can be used to obtain the following data through regression analysis: , , , , The quantized value.

[0082] For the tetrahedral structure in Example 1, the parameters of the formula for the bulk density decay rate of the tetrahedral solid structure can be determined by the least squares method. , , , , The values ​​are 0.023, 0.069, -1.609, -0.041, and -0.484, respectively. Therefore, the expression for the density decay rate of the solid tetrahedral debris flow structure is obtained as follows:

[0083] ,

[0084] In the formula: It indicates the relative scale of debris flows and characterizes the relationship between tetrahedral structure and debris flow scale; The volumetric concentration of debris flow soil before tetrahedral structure regulation is used to characterize the fluid properties of debris flow. The Froude number represents the motion state of debris flow before the tetrahedral structure regulates it. It is the tangent of the longitudinal slope of the ditch.

[0085] For the tetrahedral structure in Example 2, the parameters of the formula for the density decay rate of the tetrahedral solid frame structure can be determined by the least squares method. , , , , The values ​​are 0.021, 0.056, -1.258, 0.037, and -0.656, respectively. Therefore, the expression for the debris flow unit weight attenuation rate of the tetrahedral solid frame structure is obtained as follows:

[0086] ,

[0087] In the formula: It indicates the relative scale of debris flows and characterizes the relationship between tetrahedral structure and debris flow scale; The volumetric concentration of debris flow soil before tetrahedral structure regulation is used to characterize the fluid properties of debris flow. The Froude number represents the motion state of debris flow before the tetrahedral structure regulates it. It is the tangent of the longitudinal slope of the ditch.

[0088] For the tetrahedral structure in Example 3, the parameters of the formula for the bulk density decay rate of the tetrahedral solid sphere branch structure can be determined by the least squares method. , , , , The values ​​are 0.005, 0.207, -2.099, 0.056, and -0.732, respectively. Therefore, the expression for the density decay rate of debris flow in a tetrahedral solid sphere branched structure is obtained as follows:

[0089] ,

[0090] In the formula: It indicates the relative scale of debris flows and characterizes the relationship between tetrahedral structure and debris flow scale; The volumetric concentration of debris flow soil before tetrahedral structure regulation is used to characterize the fluid properties of debris flow. The Froude number represents the motion state of debris flow before the tetrahedral structure regulates it. It is the tangent of the longitudinal slope of the ditch.

[0091] The method for constructing the debris flow bulk density reduction rate prediction model in this embodiment comprehensively considers core influencing factors such as the initial bulk density of the debris flow, the scale of the outbreak, the longitudinal slope of the channel, and the geometric morphology of the tetrahedral structure. It can achieve accurate quantitative prediction of the bulk density reduction rate of debris flows under different tetrahedral configurations.

[0092] Example 5

[0093] This embodiment provides a method for predicting the bulk density decay rate of debris flows, in order to estimate and evaluate the effectiveness of the tetrahedral structure used for bulk density control of debris flows as described in Embodiment 1 above. The method includes the following steps:

[0094] Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements.

[0095] Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ;

[0096] Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c， Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m). 3 ;

[0097] Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2h0 represents mud depth, in meters (m).

[0098] Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers;

[0099] Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r1 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r1 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation.

[0100] The debris flow density decay rate prediction method in this embodiment is applicable to the refined assessment of the disaster risk of high-density debris flows and the design of prevention and control engineering schemes in mountainous debris flow gully scenarios. It overcomes the technical bottlenecks of the limitations and lack of flexibility of traditional empirical methods in the dynamic control of debris flow density, and further enriches the measures and technical means for the control of debris flow density in mountainous areas of my country, providing key parameter support and technical guarantee for debris flow disaster prevention and control.

[0101] In the experiment of controlling the bulk density of debris flow using a regular tetrahedral solid structure as described in Example 1, the bulk density of debris flow was measured to be 1700 kg / m³ when the slope was 7°, and the debris flow volume was 0.3 m³. Under the condition of a regular tetrahedral solid structure, the bulk density of debris flow decreased by 39.48%. At the same time, the debris flow velocity was measured to be 0.5316 m / s and the mud depth was 0.0231 m in the simulation experiment.

[0102] Based on the above, the parameters can be obtained as follows:

[0103]

[0104] 0.4145;

[0105] =1.2225;

[0106] =0.1228.

[0107] Substitute the parameters obtained above into the formula for the density decay rate of debris flow in a tetrahedral solid structure for calculation:

[0108]

[0109]

[0110] According to the calculation results, the attenuation rate of the solid structure of a regular tetrahedron to the bulk density of debris flow is... The result differs from the actual measured bulk density decay rate of 39.48% by an error of (39.48% - %). The result of 2.88% (%) / 39.48% = 2.88%, indicating that the prediction model established in this embodiment has high accuracy and good applicability. The prediction result of the debris flow bulk density decay rate can accurately reflect the influence of the tetrahedral solid structure on the debris flow bulk density, and the error is within a reasonable range.

[0111] Example 6

[0112] This embodiment provides a method for predicting the bulk density decay rate of debris flows, in order to estimate and evaluate the effectiveness of the tetrahedral structure used for bulk density control of debris flows as described in Embodiment 2 above. The method includes the following steps:

[0113] Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements.

[0114] Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Where Cv represents the soil volume concentration of the debris flow mixture; γ c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ;

[0115] Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c， Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c This indicates the total volume of the debris flow, in m3. Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m).3 ;

[0116] Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m).

[0117] Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers;

[0118] Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r2 The calculation is iterated until the debris flow density decay rate ωr2 converges to the expected target value, the optimal number of tetrahedral structures N is determined, and the estimated debris flow density decay rate after using the corresponding tetrahedral structure is finally obtained.

[0119] In the experiment of controlling the bulk density of debris flow using the tetrahedral solid frame structure in Example 2, the bulk density of the debris flow was measured to be 1700 kg / m³ at a slope of 7°, and the debris flow volume was 0.3 m³. Under the condition of a tetrahedral solid frame structure, the bulk density reduction rate of the debris flow was 43.07%. In addition, in the simulation experiment, the flow velocity of the debris flow was measured to be 0.5835 m / s, and the mud depth was 0.0161 m.

[0120] Based on the above, the parameters can be obtained as follows:

[0121]

[0122] 0.4145;

[0123] =2.1209;

[0124] =0.1228.

[0125] Substitute the parameters obtained above into the formula for the debris flow unit weight reduction rate of a tetrahedral solid frame structure for calculation:

[0126]

[0127]

[0128] According to the calculation results, the attenuation rate of the solid tetrahedral frame structure for debris flow density is... The result, compared to the actual measured bulk density decay rate of 43.07%, has an error of 5.4%, indicating that the prediction model established in this embodiment has high accuracy and good applicability. The predicted bulk density decay rate of debris flows can accurately reflect the influence of the tetrahedral solid frame structure on the bulk density of debris flows, and the error is within a reasonable range.

[0129] Example 7

[0130] This embodiment provides a method for predicting the bulk density decay rate of debris flows, in order to estimate and evaluate the effectiveness of the tetrahedral structure used for bulk density control of debris flows as described in Embodiment 3 above. The method includes the following steps:

[0131] Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements.

[0132] Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ;

[0133] Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c， Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m).3 ;

[0134] Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m).

[0135] Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers;

[0136] Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r3 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r3 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation.

[0137] In the experiment of controlling the bulk density of debris flow using the tetrahedral solid sphere branch structure in Example 3, the measured slope at the test site was 7° and the bulk density of debris flow was 1700 kg / m³. 3 The debris flow density decay rate was 46.86% under the working condition of a debris flow scale of 0.3 m³ and a number of tetrahedral solid sphere branch structures of 1. In addition, in the simulation experiment, the flow velocity of the debris flow was measured to be 0.5813 m / s and the mud depth was 0.0114 m.

[0138] Based on the above, the parameters can be obtained as follows:

[0139]

[0140] 0.4145;

[0141] =2.9688;

[0142] =0.1228.

[0143] Substitute the parameters obtained above into the formula for the density decay rate of debris flow in a tetrahedral solid sphere branched structure for calculation:

[0144]

[0145]

[0146] According to the calculation results, the attenuation rate of the solid tetrahedral sphere branch structure on the bulk density of debris flows is 50.54%. This result differs from the actual measured attenuation rate of 46.86% by only 3.68%, indicating that the prediction model established in this embodiment has high accuracy and good applicability. The predicted attenuation rate of debris flows can accurately reflect the influence of the solid tetrahedral sphere branch structure on the bulk density of debris flows, and the error is within a reasonable range.

[0147] Example 8

[0148] This embodiment provides a method for controlling the bulk density of debris flows, including the following steps:

[0149] Step S1: Use the debris flow bulk density decay rate prediction method as described in Examples 5, 6 or 7 above to obtain the number N of the optimal tetrahedral structures corresponding to the tetrahedral structures.

[0150] Step S2: Using numerical simulation methods (such as RAMMS, RapidMassMovement Simulation, or rapid mass movement simulation software) or existing debris flow dam failure simulation experimental devices, simulation conditions are set based on the relevant parameters collected in the debris flow bulk density decay rate prediction method mentioned above. At the same time, the number N tetrahedral structures obtained in step S1 are applied to adjust and optimize the optimal throwing spacing and arrangement of the tetrahedral structures.

[0151] Step S3: Based on the best simulation results obtained in step S2, the corresponding tetrahedral structure is launched into the target channel.

[0152] The debris flow bulk density control method in this embodiment can be used as a key technical means to effectively prevent and mitigate disaster risks and significantly reduce the structural damage to protective structures by controlling the bulk density of debris flows. It has important engineering practical significance.

Claims

1. A method for predicting the bulk density decay rate of debris flows, used to estimate and evaluate the effectiveness of tetrahedral structures for regulating the bulk density of debris flows, characterized in that, Includes the following steps: Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements. Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ; Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m). 3 ; Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m). Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers; Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r1 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r1 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation. Among them, the tetrahedral structure used for debris flow bulk density control is a regular tetrahedral solid structure, and the minimum length of its edges is: and The larger value in; where u c The initial flow velocity of the tetrahedral structure is expressed in m / s and is determined based on the flow velocity of the debris flow; k represents an empirical coefficient, ranging from 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³. 3 ;γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

2. A method for predicting the bulk density decay rate of debris flows, used to estimate and evaluate the effectiveness of tetrahedral structures for debris flow bulk density regulation, characterized in that... Includes the following steps: Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements. Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ; Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c， Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m). 3 ; Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m). Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers; Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r2 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r2 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation. The tetrahedral structure used for debris flow density control is a solid tetrahedral frame structure, consisting of four identical solid columns. One end of each column is connected to a single point, and the remaining ends form the four vertices of the tetrahedron in spatial arrangement. The minimum length of each solid column is: and The larger of the values ​​is given, and the diameter of the circumcircle of the solid column's cross-section is 0.15 to 0.35 times its length; where uc represents the starting velocity of the tetrahedral structure, in m / s, determined based on the debris flow velocity; k represents an empirical coefficient, taken as 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³; γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

3. The method for predicting the bulk density decay rate of debris flows according to claim 2, characterized in that, The solid cylinder is either a cylinder or a prism.

4. A method for predicting the bulk density decay rate of debris flows, used to estimate and evaluate the effectiveness of tetrahedral structures for regulating the bulk density of debris flows, characterized in that... Includes the following steps: Step S1: Conduct surveys and deployment planning for the target gullies, focusing on locating the gentler slope sections within the flat areas of the gullies, and determining the longitudinal slope θ of the gullies through topographic maps and on-site measurements. Step S2: Determine the unit weight γ of the debris flow mixture by on-site sampling or using historical data. c Calculate the soil volume concentration of the debris flow mixture. Among them, C v γ represents the soil volume concentration of a debris flow mixture; c The unit of density of debris flow mixture is kg / m³. 3 ;γ t This indicates the unit weight of the soil in a debris flow mixture, expressed in kg / m³. 3 γ represents the specific gravity of water, in kg / m³. 3 ; Step S3: Estimate the total volume V of the debris flow based on historical disaster records or hydrological models. c， Then calculate the relative scale of the debris flow. ;in, V represents the relative scale of a debris flow. c The volume of the debris flow is expressed in meters (m). 3 ; Indicates the number of tetrahedral structures; V t The volume of a single tetrahedral structure is expressed in meters (m). 3 ; Step S4: Obtain the debris flow velocity v0 using channel video monitoring or flow velocity sensors, obtain the mud depth h0 through channel cross-section sensors or historical post-disaster trace inversion, and calculate the Froude number. Among them, F r The deflector is the Froude number; v0 represents the flow velocity of the debris flow, in m / s; g represents the acceleration due to gravity, in m / s². 2 h0 represents mud depth, in meters (m). Step S5, calculate the longitudinal slope gradient θ of the gully and the soil volume concentration of the debris flow mixture. The relative scale of debris flows , Froude number Import the prediction model and calculate the bulk density decay rate of debris flow. ;in, θ represents the density decay rate of debris flow; θ represents the longitudinal slope gradient of the gully. This indicates the soil volume concentration of the debris flow mixture. Indicates the relative scale of a debris flow; Represent Froude numbers; Step S6: Change the number N of tetrahedral structures, and re-import the adjusted number N into the prediction model to recalculate the debris flow unit weight decay rate ω. r3 Iterative calculations are performed until the debris flow unit weight decay rate ω is reached. r3 The convergence to the expected target value determines the optimal number N of tetrahedral structures, and finally obtains the estimated debris flow density decay rate after using the corresponding tetrahedral structure for regulation. The tetrahedral structure used for debris flow density control is a regular tetrahedral solid sphere branched structure, consisting of a solid sphere, four identical solid thick-long cylinders, and thirty-six identical solid thin-short cylinders. One end of each of the four identical solid thick-long cylinders is fixed to a corresponding position on the solid sphere, and the remaining end forms the four vertices of the regular tetrahedron in space. The thirty-six solid thin-short cylinders are divided into four large groups, each of which is further divided into three smaller groups. Each smaller group includes three solid thin-short cylinders, one end of which is fixed to the solid thick-long cylinder, and the other end forms the three vertices of the regular tetrahedron in space. The minimum diameter of the solid sphere is [missing information]. and The larger of the values; the minimum length of a solid, thick, long cylinder is: and The larger of the values, and the diameter of the circumcircle of the cross-section of a solid, thick, long prism is 0.2 to 0.4 times its length; the minimum length of a solid, thin, short prism is: and The larger of the values ​​in the equation, and the circumcircle diameter of the solid, slender prism cross-section is 0.4 to 0.6 times its length; where uc represents the starting velocity of the tetrahedral structure, in m / s, determined based on the debris flow velocity; k represents an empirical coefficient, taken as 5.0 to 7.0 m. 0.5 / s, a value determined based on actual conditions at the engineering site; γ represents the specific gravity of water, in kg / m³. 3 ;γ s The density of a tetrahedral structure is expressed in kg / m³. 3 The value is determined based on the material of the tetrahedral structure; g represents the acceleration due to gravity, in m / s². 2 K represents the stability coefficient, which ranges from 0.68 to 0.72, and is determined based on the actual conditions at the engineering site.

5. The method for predicting the bulk density decay rate of debris flows according to claim 4, characterized in that, The solid, thick, long cylinder is either a cylinder or a prism; And / or, the solid, slender cylinder is a cylinder or a prism.

6. A method for constructing a debris flow bulk density decay rate prediction model, to obtain the prediction model used in the debris flow bulk density decay rate prediction method as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: Conduct a physical simulation experiment of debris flow movement in a flume under multiple working conditions to obtain the factors affecting the control of the tetrahedral structure on the bulk density of the debris flow. The control factors include: characteristic dimensions of the tetrahedral structure, channel conditions, debris flow properties before tetrahedral structure control, and debris flow movement state before tetrahedral structure control. The characteristic dimensions of the tetrahedral structure include: edge length L of a solid tetrahedral structure, virtual edge length L of a solid tetrahedral frame structure, or virtual edge length L of a solid tetrahedral sphere branch structure, effective height H, and volume V. t The quantity N; the channel conditions include: the longitudinal slope θ of the channel; the debris flow properties before the tetrahedral structure regulation include: the unit weight γ of the mixture. c Total volume V c Characteristic particle size d of soil particles r The tetrahedral structure was used to regulate the debris flow motion state before the flow velocity v0 and the mud depth h0. Step S2: Dimensional analysis is used to analyze the control factors and create a predictive model for the control of debris flow bulk density by tetrahedral structure.

7. A method for controlling the bulk density of debris flows, characterized in that, Includes the following steps: Step S1: Use the debris flow bulk density decay rate prediction method as described in any one of claims 1 to 5 to obtain the number N of the optimal tetrahedral structures corresponding to the tetrahedral structures. Step S2: Using numerical simulation or debris flow dam failure simulation experimental device, set simulation conditions based on relevant parameters collected in the debris flow unit weight attenuation rate prediction method. At the same time, apply the N tetrahedral structures obtained in step S1, and adjust and optimize to obtain the optimal throwing spacing and arrangement of the tetrahedral structures. Step S3: Based on the best simulation results obtained in step S2, the corresponding tetrahedral structure is launched into the target channel.

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