A method for predicting geometric parameters of a barrier dam

Abstract

The application discloses a kind of prediction methods of damming dam geometric form parameters, comprising: obtaining physical parameters and topography and geomorphology parameters to establish the calculation model of damming dam formation process;Analysis landslide volume, sliding surface inclination, landslide body natural repose angle and landslide speed influence on damming dam geometric form parameters obtain the fitting formula.Distribution position and volume of potential landslide body entering valley are obtained, based on the distribution position and the volume of potential landslide body entering valley, the volume of potential landslide body entering valley per unit time is obtained;Compare the volume of potential landslide body entering valley and river flow, to determine whether damming dam can be formed;Obtain the state parameters of potential landslide body and potential damming dam;Based on the geometric formula, the state parameters of potential landslide body and potential damming dam, the geometric form parameters of damming dam are predicted.The application can predict the geometric form of potential damming dam in advance, and provide a new method for the prediction and early warning of mountain damming dam geological disasters.

Description

Technical Field

[0001] This invention belongs to the field of geological disaster prevention and mitigation of landslide dams, and in particular relates to a method for predicting the geometric parameters of landslide dams. Background Technology

[0002] Landslide dams, caused by rockfalls, landslides, and debris flows, are common geological hazards in high mountain and canyon regions worldwide. The stability of landslide dams varies greatly, with lifespans ranging from hours to years. Once a landslide dam breaks, it can cause catastrophic floods, posing a significant threat to downstream people and their property. For example, during the 2008 Wenchuan earthquake in China, the collapse of a landslide dam severely threatened the lives of nearly one million people downstream. The Baige landslide dam, which formed in China in 2018, directly caused economic losses of 15 billion yuan. Research shows that the formation process of landslide dams can affect the geometry of the dam body, thereby affecting the water storage capacity of the landslide-dammed lake, and further influencing the scale of potential flood disasters. Therefore, the three-dimensional geometry of landslide dams is a key parameter for disaster prevention and mitigation, summarized in the following three aspects: First, the height of the landslide dam determines the reservoir capacity of the landslide-dammed lake. Second, the stability of a landslide dam is generally affected by its geometry. Third, the geometry of a landslide dam is a crucial prerequisite for assessing the outburst flood flow caused by dam failure. Therefore, predicting the three-dimensional geometry of potential landslide dams after determining that a landslide may occur would provide crucial technical support for the prediction and early warning of landslide dam disasters. However, current prediction methods do not adequately consider the influencing factors, leading to inaccurate prediction results. Summary of the Invention

[0003] The purpose of this invention is to provide a method for predicting the geometric parameters of landslide dams, so as to solve the problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides a method for predicting the geometric parameters of a landslide dam, comprising:

[0005] Numerical analysis and calculation model of the formation process of the landslide dam was established by obtaining the physical and mechanical parameters of the landslide body and the topographic elevation parameters.

[0006] Based on the numerical analysis and calculation model, the influence of landslide volume, sliding surface dip angle, landslide body natural repose angle and landslide body velocity on the geometric parameters of the landslide dam is used to obtain a fitting formula.

[0007] The distribution location and volume of potential landslide bodies entering the valley are obtained, and the volume entering the valley per unit time is obtained based on the distribution location and the volume entering the valley.

[0008] By comparing the volume of water entering the valley with the river flow, it can be determined whether a landslide dam has formed.

[0009] If a landslide dam can form, the geometric parameters of the landslide dam corresponding to the potential landslide body are predicted based on the fitting formula, the state parameters of the potential landslide body and the potential landslide dam.

[0010] Optionally, a computational model of the landslide dam formation process can be constructed using a smoothed fluid dynamics method, wherein the sliding surface and the riverbed are simulated as rigid bodies without considering deformation, and the landslide particles are simulated using a constitutive model considering Mohr-Coulomb.

[0011] Optionally, the process of obtaining the volume entering the valley per unit time includes:

[0012] The centroid of the landslide is identified, and the sliding velocity of the landslide is calculated based on the centroid location and the volume entering the valley. The sliding time is then obtained, and the water inflow per unit time of the landslide is calculated based on the sliding time and the volume entering the valley.

[0013] Optionally, if the volume of landslide entering the valley per unit time is a preset multiple of the river flow, it is considered that a landslide dam may form; otherwise, it is considered that a landslide dam may not form.

[0014] Optionally, the state parameters of the potential landslide body include: the location of the potential landslide body, the angle of repose, the volume, the width, the location and dip angle of the potential sliding surface;

[0015] The state parameters of a potential landslide dam include: river flow in the area where the dam is located, the slope angles of the left and right banks of the valley, the bottom width of the valley, and the inclination angle of the riverbed.

[0016] Optionally, the fitting formulas include the formulas for predicting the maximum width of the landslide dam, the length of the landslide dam, the maximum height of the landslide dam, and the minimum height of the landslide dam.

[0017] The formula for predicting the maximum width of a landslide dam is expressed as follows:

[0018]

[0019] In the formula, w max V is the maximum width of the landslide dam, V is the volume of the landslide mass entering the river, v is the sliding velocity of the landslide mass, l is the length of the landslide dam, α is the dip angle of the sliding surface, and θ is the dip angle of the riverbed. θ is the natural angle of repose of the landslide, and g is the acceleration due to gravity.

[0020] Optionally, the formula for predicting the length of a landslide dam is expressed as follows:

[0021]

[0022] In the formula, l is the length of the landslide dam, b is the width of the valley floor, and φ is the width of the dam. l and φ r These are the slope angles of the left and right banks of the river valley, respectively.

[0023] Optionally, the formula for predicting the maximum height of a landslide dam is expressed as follows:

[0024]

[0025] In the formula, h max This indicates the maximum height of the landslide dam.

[0026] Optionally, the formula for predicting the minimum height of a landslide dam is expressed as follows:

[0027]

[0028] In the formula, h min This indicates the minimum height of the landslide dam.

[0029] The technical effects of this invention are as follows:

[0030] Based on the state of potential landslide bodies, this method can predict in advance whether a landslide dam will form and the geometric shape of any formed landslide dam. This fills the gap in empirical formulas for predicting the geometric shape of landslide dams and provides a new method for predicting and warning of geological disasters caused by landslide dams in mountainous areas. Attached Figure Description

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0032] Figure 1 This is a flowchart of the method for predicting the geometric parameters of a landslide dam in an embodiment of the present invention;

[0033] Figure 2 The above are simulation results of the landslide dam formation process based on the smooth fluid dynamics method in the embodiments of the present invention;

[0034] Figure 3 The figure shows the fitting results of the expressions for the maximum dam width, maximum dam height and minimum dam height in the embodiment of the present invention, where (a) is the maximum dam height, (b) is the minimum dam height and (c) is the maximum dam width. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0037] Example 1

[0038] like Figure 1-3 As shown, this embodiment provides a method for predicting the geometric parameters of a landslide dam, including:

[0039] S1: Obtain the physical and mechanical parameters of the landslide body and the topographic elevation parameters to establish a numerical analysis and calculation model of the formation process of the landslide dam;

[0040] S2: Numerical simulation analysis of the influence of landslide volume, sliding surface dip angle, landslide body angle of repose and landslide body velocity on the morphological characteristics of the landslide dam, and establishment of quantitative relationships between the above physical quantities;

[0041] S3: Through geological surveys, determine the location, angle of repose, volume, width, location and dip angle of potential landslide bodies, and record them; if cracks are found on the slope, or if the slope has shifted, the slope is considered a potential landslide.

[0042] S4: Through geological surveys, determine the river flow, left and right bank slope angles, valley bottom width, and riverbed dip angle in the area where a potential landslide dam may be located;

[0043] S5: Compare the volume of landslide entering the valley per unit time with the river flow rate to determine whether a landslide dam may form;

[0044] S6: If it is determined that a landslide dam may form, the geometric parameters of the landslide dam are predicted according to the calculation formula provided in this invention.

[0045] In this implementation scheme, a computational model of the formation process of the landslide dam was established in S1 using the smoothed fluid dynamics method. The sliding surface and the riverbed were simulated as rigid bodies without considering deformation, and the landslide particles were simulated using a constitutive model considering Mohr-Coulomb. Figure 2 Simulation results of the landslide dam formation process based on the smooth fluid dynamics method are presented.

[0046] The sliding surface and the sliding bed are simulated using rigid bodies without considering deformation, which can improve computational efficiency; the landslide particles are simulated using the constitutive model of Mohr-Coulomb, which can better reflect the actual movement of the landslide.

[0047] In this implementation plan, by conducting multiple sets of parameter sensitivity numerical analyses, S2 used regression analysis to establish fitting relationships between landslide volume, sliding surface dip angle, landslide body natural repose angle and landslide body velocity and the maximum dam width, maximum dam height and minimum dam height of the barrier dam. Figure 3 The fitting results for the expressions of the maximum dam width, maximum dam height, and minimum dam height of the landslide dam are presented. The fitting formulas serve as prediction formulas for the morphological parameters of the landslide dam.

[0048] In this implementation plan, the prediction of the morphological characteristics of the landslide dam relies on engineering surveys of the potential landslide body and the valley in which it is located. The surveys need to provide information such as the location of the potential landslide body, its angle of repose, volume, width, location and dip angle of the potential sliding surface, river flow, the left and right bank slope angles of the valley, the bottom width of the valley, and the riverbed dip angle.

[0049] It should be noted that after a landslide occurs, the landslide mass does not necessarily enter the river channel completely; part of the landslide remains on the original slope. Based on expert experience, the volume of the landslide mass entering the valley is estimated, and the sliding velocity and sliding time are estimated based on the height difference between its center of gravity and the bottom of the valley. The volume of the landslide entering the valley per unit time is estimated using the ratio of the volume to the sliding time. If the volume of the landslide entering the valley per unit time is 1.5 times the river flow, a landslide dam is considered likely to form; otherwise, a landslide dam is not considered likely. In this implementation plan, it is necessary to identify the distribution locations of landslide masses that may enter the valley and determine the volume of landslide masses entering the river channel. Based on the distribution locations of landslide masses that may enter the river channel, their center of gravity locations are determined. Based on this, a formula is used... Estimate the landslide velocity, where v is the landslide velocity, h is the vertical distance from the center of mass to the valley floor, and g is the acceleration due to gravity. After obtaining the landslide velocity, estimate the sliding time based on the length of the sliding path; based on the sliding time and the volume of landslide entering the river channel, estimate the volume of landslide entering the river per unit time, and compare it with the river flow rate to determine whether a landslide dam is likely to form.

[0050] Based on the aforementioned state parameters of the landslide body and its valley as provided by the survey, the geometric morphology of the potential landslide dam is predicted using the dam morphology parameter prediction formula provided in this invention.

[0051] The formula for predicting the geometry of landslide dams provided by this invention is expressed as follows.

[0052] The maximum width of a landslide dam is predicted using the following formula;

[0053]

[0054] In the formula: w maxV is the maximum width of the landslide dam, V is the volume of the landslide mass entering the river, v is the sliding velocity of the landslide mass, l is the length of the landslide dam, α is the dip angle of the sliding surface, and θ is the dip angle of the riverbed. θ is the natural angle of repose of the landslide, and g is the acceleration due to gravity.

[0055] The length of a landslide dam is predicted using the following formula:

[0056]

[0057] In the formula: l is the length of the landslide dam, b is the width of the valley floor, φ1 and φ r These are the slope angles of the left and right banks of the river valley, respectively.

[0058] The maximum height of a landslide dam is predicted using the following formula;

[0059]

[0060] Where: h max It is the maximum height of the landslide dam.

[0061] The minimum height of a landslide dam is predicted using the following formula;

[0062]

[0063] Where: h min It is the minimum height of the landslide dam.

[0064] Based on the implementation scheme and model formula provided by this invention, potential landslide bodies can be discovered in the watershed, and the formation of landslide dams and their geometric shapes can be determined in advance, providing a new method for predicting and warning of geological disasters caused by landslide dams in mountainous areas.

[0065] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for predicting the geometric parameters of a landslide dam, characterized in that, Includes the following steps: Numerical analysis and calculation model of the formation process of the landslide dam was established by obtaining the physical and mechanical parameters of the landslide body and the topographic elevation parameters. Based on the numerical analysis and calculation model, the influence of landslide volume, sliding surface dip angle, landslide body natural repose angle and landslide body velocity on the geometric parameters of the landslide dam is used to obtain a fitting formula. The distribution location and volume of potential landslide bodies entering the valley are obtained, and the volume entering the valley per unit time is obtained based on the distribution location and the volume entering the valley. By comparing the volume of water entering the valley with the river flow, it can be determined whether a landslide dam has formed. If a landslide dam can form, then based on the fitting formula and the state parameters of the potential landslide body and the potential landslide dam, the geometric parameters of the landslide dam formed by the potential landslide body are predicted. The state parameters of the potential landslide body include: the location of the potential landslide body, the angle of repose, the volume, the width, and the location and dip angle of the potential sliding surface; The state parameters of potential landslide dams include: river flow in the area where the landslide dam is located, the slope angles of the left and right banks of the valley, the bottom width of the valley, and the dip angle of the riverbed; The formula for predicting the length of a landslide dam is expressed as: In the formula, b is the length of the landslide dam, and b is the width of the river valley floor. and These are the slope angles of the left and right banks of the river valley, respectively. The formula for predicting the maximum height of a landslide dam is expressed as: In the formula, Indicates the maximum height of the landslide dam; It is the volume of the landslide entering the river. It is the sliding velocity of the landslide body. It is the length of the landslide dam. It is the inclination angle of the sliding surface. It is the angle of the riverbed. It is the natural angle of repose of the landslide. It is gravitational acceleration; The formula for predicting the minimum height of a landslide dam is expressed as: In the formula, This indicates the minimum height of the landslide dam.

2. The method for predicting the geometric parameters of a landslide dam according to claim 1, characterized in that, A computational model of the landslide dam formation process was constructed using the smoothed fluid dynamics method. The sliding surface and the riverbed were simulated as rigid bodies without considering deformation, while the landslide particles were simulated using a constitutive model considering Mohr-Coulomb.

3. The method for predicting the geometric parameters of a landslide dam according to claim 1, characterized in that, The process of obtaining the volume of water entering the valley per unit time includes: The centroid of the landslide is identified, and the sliding velocity of the landslide is calculated based on the centroid location and the volume entering the valley. The sliding time is then obtained, and the water inflow per unit time of the landslide is calculated based on the sliding time and the volume entering the valley.

4. The method for predicting the geometric parameters of a landslide dam according to claim 1, characterized in that, If the volume of landslide entering the valley per unit time is a preset multiple of the river flow, it is considered that a landslide dam may form; otherwise, it is considered that a landslide dam may not form.

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