A method for determining equivalent calculation parameters of landslide surge under seismic dynamic action

Abstract

The present invention provides a method for determining equivalent calculation parameters of landslide surge under seismic dynamic action. Based on the equivalent relationship between the limit equilibrium states of landslides corresponding to the presence and absence of seismic dynamic action, the corresponding relationship between the original parameters and the equivalent parameters is established, so as to determine the equivalent calculation parameters of landslide surge under seismic dynamic action. The present invention equivalently represents the seismic dynamic action as the weakening of landslide parameters, and uses the equivalent relationship of the limit equilibrium safety factor to deduce the numerical calculation parameters of landslide surge under seismic dynamic action. The present invention equivalently represents the seismic dynamic action as the weakening of mechanical parameters. The method has a simple process and strong operability, and can effectively solve the problem of difficult application of seismic dynamic action in the existing numerical simulation of landslide surge, thereby effectively preventing the occurrence of surge disasters under seismic dynamic action.

Description

Technical Field

[0001] The present invention relates to the field of numerical simulation of landslide-induced surges, and particularly to a method for determining equivalent calculation parameters of landslide-induced surges under seismic dynamic action. Background Art

[0002] In alpine and canyon areas, earthquakes are likely to trigger landslides. When a landslide in a reservoir area becomes unstable and fails under seismic dynamic action and the sliding mass rushes into the water body at a very high speed, huge surge waves will be generated in the water body. Landslide-induced surges are the surge waves caused by the sudden sliding of the rock and soil mass on the reservoir area slope and impacting the reservoir water. Small landslides do not cause much harm, but when a large landslide with a huge sliding mass rushes into the reservoir at a very high speed, huge surge waves will be generated in the water body, rushing towards the opposite bank, water retaining structures, docks, etc., and the surge waves will produce a climbing phenomenon, thus overtopping the dam crest and endangering the dam body and the downstream. How to correctly evaluate the disaster of landslide-induced surges caused by earthquakes and thus carry out targeted prevention and control has important scientific significance and engineering value.

[0003] Appropriate numerical simulation methods can more accurately simulate the generation and propagation laws of landslide-induced surges, etc. The simulation results can provide guiding opinions for the prevention of landslide-induced surges and engineering disaster prevention and mitigation. In existing landslide-induced surge numerical simulation software, the simulation of seismic dynamic action is relatively cumbersome, and some existing software does not support the simulation of seismic dynamic action and cannot effectively apply the seismic dynamic action to the landslide, which seriously hinders the correct simulation of the surge disaster caused by the landslide under seismic dynamic action. Summary of the Invention

[0004] Aiming at the above technical problems, the present invention proposes a method for determining equivalent calculation parameters of landslide-induced surges under seismic dynamic action, which can effectively apply the seismic dynamic action to the landslide and can be applied in the simulation of landslide-induced surges.

[0005] The present invention adopts the following technical solutions:

[0006] A method for determining equivalent calculation parameters of landslide-induced surges under seismic dynamic action, for a target landslide area, the following steps are executed to obtain the equivalent calculation parameters of landslide-induced surges of each preset type of soil layer in the target landslide area under seismic dynamic action, which are used for the numerical simulation calculation of landslide-induced surges in the target landslide area under seismic dynamic action:

[0007] Step A: For the target landslide area, obtain the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force;

[0008] Step B: For the target landslide area, vertically divide the soil layer in the target landslide area into a preset number of strip-shaped soil layer blocks along the horizontal direction corresponding to the highest point to the lowest point of the landslide, and establish a landslide slice model of the target landslide area;

[0009] Step C: Based on the landslide slice model of the target landslide area and the cohesion and internal friction angle of each preset type of soil layer in the target landslide area under no external force, combined with the seismic acceleration of the preset target landslide area, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action;

[0010] Step D: Based on the limit equilibrium safety factor of the target landslide area under seismic dynamic action, combined with the cohesion and internal friction angle of each preset type of soil layer in the target landslide area under no external force, obtain the equivalent calculation parameters of landslide surge for each preset type of soil layer in the target landslide area under seismic dynamic action.

[0011] Preferably, in the said Step C, specifically through the following steps, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action:

[0012] Step C1: Based on the landslide slice model of the target landslide area, combined with the seismic acceleration of the preset target landslide area, obtain the horizontal seismic load of each strip-shaped soil layer block in the target landslide area under seismic dynamic action;

[0013] Step C2: Based on the horizontal seismic load of each strip-shaped soil layer block, obtain the vertical seismic load of each strip-shaped soil layer block under seismic dynamic action;

[0014] Step C3: Based on the horizontal seismic load and vertical seismic load of each strip-shaped soil layer block, combined with the landslide slice model of the target landslide area and the cohesion and internal friction angle of each preset type of soil layer in the target landslide area under no external force, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action.

[0015] Preferably, in the said Step C1, for each strip-shaped soil layer block respectively, through the following formula, obtain the horizontal seismic load of this strip-shaped soil layer block under seismic dynamic action, and then obtain the horizontal seismic loads of each strip-shaped soil layer block under seismic dynamic action:

[0016] F hi =α w W i α i

[0017] In the formula, F hi represents the horizontal seismic load of strip-shaped soil layer block i; α w represents the comprehensive horizontal seismic coefficient, a h represents the seismic acceleration of the preset target landslide area; ξ represents the preset reduction coefficient; g represents the acceleration of gravity; W i represents the self-gravity borne by strip-shaped soil layer block i; a i represents the dynamic distribution coefficient of strip-shaped soil layer block i.

[0018] Preferably, in the step C2, for each strip-shaped soil layer block, the vertical seismic load of the strip-shaped soil layer block under the action of seismic dynamic force is obtained through the following formula, and then the vertical seismic loads of each strip-shaped soil layer block under the action of seismic dynamic force are obtained:

[0019] F vi = F hi / 3

[0020] In the formula, F vi represents the vertical seismic load of the strip-shaped soil layer block i; F hi represents the horizontal seismic load of the strip-shaped soil layer block i.

[0021] Preferably, in the step C3, the limit equilibrium safety factor of the target landslide area under the action of seismic dynamic force is obtained through the following formula:

[0022]

[0023] In the formula, c i represents the cohesion of the preset type of soil layer without external force; represents the internal friction angle of the preset type of soil layer without external force; W i represents the self-gravity of the strip-shaped soil layer block i; N i represents the normal reaction force on the bottom surface of the strip-shaped soil layer block i; d i represents the bottom slope angle of the strip-shaped soil layer block i; l i represents the arc length of the bottom surface of the strip-shaped soil layer block i; F vi represents the vertical seismic load of the strip-shaped soil layer block i under the action of seismic dynamic force; F hi represents the horizontal seismic load of the strip-shaped soil layer block i under the action of seismic dynamic force; F s represents the limit equilibrium safety factor of the target landslide area under the action of seismic dynamic force; I represents the total number of preset strip-shaped soil layer blocks; s represents the preset type of soil layer, and S represents the total number of preset types of soil layers.

[0024] Preferably, in the step D, the equivalent calculation parameters of the landslide surge of each preset type of soil layer in the target landslide area under the action of seismic dynamic force are obtained through the following process:

[0025] Step D1: An equivalent formula of the limit equilibrium safety factor is constructed through the following formula:

[0026]

[0027] In the formula, F′ s represents the equivalent parameter of the limit equilibrium safety factor of the target landslide area under the action of seismic dynamic force; c′ iThe equivalent parameter representing the cohesion of the preset type of soil layer in the target landslide area under the action of earthquake dynamics; The equivalent parameter representing the internal friction angle of the preset type of soil layer in the target landslide area under the action of earthquake dynamics; i W represents the arc length of the bottom surface of strip soil block i; i represents the gravity of strip soil block i; N i represents the normal reaction force on the bottom surface of strip soil block i; d i represents the bottom slope angle of strip soil layer block i; I represents the total number of preset strip soil layer blocks; s represents the preset type of soil layer, and S represents the total number of preset type of soil layers;

[0028] Step D2: Under no external force, the cohesion and internal friction angle of each preset type of soil layer in the target landslide area are iteratively weakened in equal proportion to obtain c′ i and c′ obtained at each iteration i and Substitute the equivalent formula to obtain F′ s , until F′ s Equal to the limit equilibrium safety factor of the target landslide area under earthquake dynamics, the iteration ends, and the output is F′ s c′ corresponding to each preset type of soil layer when the limit equilibrium safety factor of the target landslide area under earthquake dynamics is equal i and As the equivalent calculation parameter of landslide surge in the preset type of soil layer in the target landslide area under the action of earthquake dynamics.

[0029] The beneficial effects of the present invention are as follows: the present invention proposes a method for determining equivalent calculation parameters of landslide surge waves under earthquake dynamic action, establishes a correspondence between original parameters and equivalent parameters based on the equivalent relationship between the landslide limit equilibrium states corresponding to earthquake dynamic action and the landslide limit equilibrium states without earthquake dynamic action, thereby determining the equivalent calculation parameters of landslide surge waves under earthquake dynamic action; the present invention equates earthquake dynamic action to the weakening of landslide parameters, and uses the equivalent relationship of limit equilibrium safety factor to infer the numerical calculation parameters of landslide surge waves under earthquake dynamic action. The present invention equates earthquake dynamic action to the weakening of mechanical parameters. The method has a simple process and strong operability, and can effectively solve the problem of difficulty in applying earthquake dynamic action in the existing numerical simulation of landslide surge waves, thereby effectively preventing surge disasters under earthquake dynamic action based on numerical simulation of landslide surge waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Flow chart of the method of the present invention;

[0031] Figure 2 This is a schematic diagram of the landslide strip model of the present invention;

[0032] Figure 3 Schematic diagram of the force on a strip-shaped soil layer block under the action of seismic forces in the present invention;

[0033] Figure 4 Schematic diagram of the force on a strip-shaped soil layer block under the equivalent parameters of the present invention;

[0034] Figure 5 Landslide slice model diagram in this embodiment. Detailed implementation manner

[0035] The present invention will be further described below with reference to the accompanying drawings. The following embodiments can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

[0036] A method for determining equivalent calculation parameters of landslide surge under the action of seismic forces, the flow chart is as Figure 1 shown. For the target landslide area, perform the following steps to obtain the equivalent calculation parameters of landslide surge for each preset type of soil layer in the target landslide area under the action of seismic forces, which are used for numerical simulation calculation of landslide surge in the target landslide area:

[0037] Step A: For the target landslide area, obtain the relevant geological profiles and parameters of the landslide. In this embodiment, a landslide in a reservoir area of a hydropower station on the Yalong River is selected. The relevant geological profiles and parameters mainly include landslide profile information, soil layer density, soil layer cohesion, and soil layer internal friction angle; based on the relevant geological profiles and parameters of the landslide, obtain the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force; Table 1 is the table of landslide-related geological parameters. Five soil layers as shown in the following table are selected in this embodiment.

[0038] Table 1 Table of landslide soil layer parameters

[0039] Material grouping Cohesion (kPa) Internal friction angle (°) <![CDATA[Severe (kg / m 3 )]]> Silty clay with gravel 90 31.0 2250 Deep sliding zone 60 31.5 2250 Colluvial deposits 45 33.0 2250 Gravelly soil mixture 70 35.0 2300 Block stone layer 100 40.0 2400

[0040] Step B: For the target landslide area, as Figure 2 shown, vertically divide the soil layer in the target landslide area into a preset number of strip-shaped soil layer blocks along the horizontal direction corresponding to the highest point to the lowest point, and establish a landslide slice model for the target landslide area; in this embodiment, a landslide slice model as Figure 5 shown is established.

[0041] Step C: Based on the landslide slice model of the target landslide area and the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force, combined with the seismic acceleration of the preset target landslide area, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action; the seismic acceleration is determined according to the existing specifications and the on-site fortification intensity. According to the provisions in the "China Seismic Ground Motion Parameter Zoning Map (GB 18306-2015)", the seismic acceleration of the preset target landslide area in this embodiment is obtained as 0.15g. The seismic acceleration of the preset target landslide area is a value based on the specifications, that is, determined by the maximum earthquake intensity that may occur in this area, so as to better prevent in advance the hazards brought by landslide surges under seismic dynamic action.

[0042] In the said Step C, specifically through the following steps, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action:

[0043] Step C1: Based on the landslide slice model of the target landslide area, combined with the seismic acceleration of the preset target landslide area, obtain the horizontal seismic load of each strip-shaped soil layer block in the target landslide area under seismic dynamic action;

[0044] In the said Step C1, for each strip-shaped soil layer block respectively, through the following formula, obtain the horizontal seismic load of this strip-shaped soil layer block under seismic dynamic action, and further obtain the horizontal seismic loads of each strip-shaped soil layer block under seismic dynamic action:

[0045] F hi =α w W i α i

[0046] In the formula, F hi represents the horizontal seismic load of strip-shaped soil layer block i; α w represents the comprehensive horizontal seismic coefficient, α h represents the seismic acceleration of the preset target landslide area; ξ represents the preset reduction coefficient, taking 0.25; g represents the acceleration of gravity; W i represents the self-gravity borne by strip-shaped soil layer block i; α i represents the dynamic distribution coefficient of strip-shaped soil layer block i, α i ∈[1, 3].

[0047] Step C2: Based on the horizontal seismic loads of each strip-shaped soil layer block, obtain the vertical seismic loads of each strip-shaped soil layer block under seismic dynamic action;

[0048] In step C2, for each strip-shaped soil layer block, the vertical seismic load of the strip-shaped soil layer block under seismic dynamic action is obtained through the following formula, and then the vertical seismic loads of each strip-shaped soil layer block under seismic dynamic action are obtained:

[0049] F vi =F hi / 3

[0050] In the formula, F vi represents the vertical seismic load of strip-shaped soil layer block i; F hi represents the horizontal seismic load of strip-shaped soil layer block i. The seismic dynamic action loads of strip-shaped soil layer blocks are shown in Table 2.

[0051] Table 2 Seismic dynamic action loads on strip-shaped soil layer blocks

[0052] Slice number <![CDATA[Horizontal seismic load F hi (kN)]]> <![CDATA[Vertical seismic load F vi (kN)]]> 1 2.37 0.79 2 39.44 13.15 3 38.50 12.83 ... ... ... 88 41.47 13.82 89 10.89 3.63 90 1.07 0.36

[0053] As Figure 3 shown is the schematic diagram of the force on the strip-shaped soil layer block under seismic dynamic action in the invention. In the figure, E i+1 is the horizontal force of the previous strip-shaped soil layer block on strip-shaped soil layer block i, E i is the horizontal force of the next strip-shaped soil layer block on strip-shaped soil layer block i, X i+1 is the frictional force of the previous strip-shaped soil layer block on strip-shaped soil layer block i, X i is the frictional force of the next strip-shaped soil layer block on strip-shaped soil layer block i. In the present invention, it is assumed that the horizontal forces on both sides of the strip-shaped soil layer block are equal in magnitude and the frictional forces are equal in magnitude. Therefore, E and X are not considered in the calculation. T i is the frictional force received by strip-shaped soil layer block i

[0054] Step C3: Based on the horizontal seismic loads and vertical seismic loads of each strip-shaped soil layer block, combined with the landslide slice model of the target landslide area and the cohesion and internal friction angle of each preset type of soil layer in the target landslide area under no external force, the limit equilibrium safety factor of the target landslide area under seismic dynamic action is obtained.

[0055] In step C3, the limit equilibrium safety factor of the target landslide area under seismic dynamic action is obtained through the following formula:

[0056]

[0057] In the formula, c i represents the cohesion of the preset type of soil layer under no external force; represents the internal friction angle of the preset type of soil layer under no external force; W i represents the self-weight of strip-shaped soil layer block i; Ni Denote the normal reaction force on the bottom surface of the strip soil layer block i; d i Denote the bottom slope angle of the strip soil layer block i; l i Denote the arc length of the bottom surface of the strip soil layer block i; F vi Denote the vertical seismic load of the strip soil layer block i under the action of seismic dynamic force; F hi Denote the horizontal seismic load of the strip soil layer block i under the action of seismic dynamic force; F s Denote the ultimate equilibrium safety factor of the soil layer of the preset type in the target landslide area under the action of seismic dynamic force; I represents the total number of preset strip soil layer blocks; s represents the preset type of soil layer, and S represents the total number of preset types of soil layers. Based on the horizontal seismic load and vertical seismic load of each strip soil layer block, and the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force, the sum calculation is carried out based on the above formula to obtain the ultimate equilibrium safety factor of the target landslide area under the action of seismic dynamic force as F s = 0.983.

[0058] Step D: Based on the ultimate equilibrium safety factor of the target landslide area under the action of seismic dynamic force, combined with the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force, obtain the equivalent calculation parameters of the landslide surge of each preset type of soil layer in the target landslide area under the action of seismic dynamic force.

[0059] In the said Step D, through the following process, obtain the equivalent calculation parameters of the landslide surge of each preset type of soil layer in the target landslide area under the action of seismic dynamic force:

[0060] Step D1: Through the following formula, construct an equivalent formula for the ultimate equilibrium safety factor, that is, the ultimate equilibrium safety factor under equivalent parameters is expressed as:

[0061]

[0062] In the formula, F′ s Denote the equivalent parameter of the ultimate equilibrium safety factor of the target landslide area under the action of seismic dynamic force; c′ i Denote the equivalent parameter of the cohesion of the preset type of soil layer in the target landslide area under the action of seismic dynamic force; Denote the equivalent parameter of the internal friction angle of the preset type of soil layer in the target landslide area under the action of seismic dynamic force; l i Denote the arc length of the bottom surface of the strip soil layer block i; W i Denote the self-weight of the strip soil layer block i; N i Denote the normal reaction force on the bottom surface of the strip soil layer block i; d i Denote the bottom slope angle of the strip soil layer block i; I represents the total number of preset strip soil layer blocks; s represents the preset type of soil layer, and S represents the total number of preset types of soil layers;

[0063] Step D2: Iteratively and proportionally weaken the cohesion and internal friction angle of each preset type of soil layer in the target landslide area under no external force to obtain c′ i and The c′ obtained from each iteration i and Substitute into the equivalent formula to obtain F′ s , until F′ s is equal to the limit equilibrium safety factor of the target landslide area under seismic dynamic action, the iteration ends, and output F′ s The c′ corresponding to each preset type of soil layer when F′ i and is equal to the limit equilibrium safety factor of the target landslide area under seismic dynamic action are used as the equivalent calculation parameters of the landslide surge of this preset type of soil layer in the target landslide area under seismic dynamic action.

[0064] Specifically, proportionally weaken the mechanical parameters (cohesion and internal friction angle) of each type of soil layer to obtain c′ i and Substitute into

[0065] Weaken and calculate multiple times, and finally find the weakening parameters that satisfy the condition F s = F′ s , which are used as the equivalent parameters for the landslide soil layer under seismic dynamic action. The equivalent parameters are shown in Table 3. As shown in Figure 4 is the schematic diagram of the force on the strip soil layer block under the equivalent parameters of the present invention. T′ i is the frictional force on the strip soil layer block i under the equivalent parameters

[0066] Table 3 Equivalent parameter table of landslide soil layer under seismic dynamic action

[0067] Material grouping Equivalent cohesion (kPa) Equivalent internal friction angle (°) <![CDATA[Severe (kg / m 3 )]]> Silty clay with gravel 78.3 27.0 2250 Deep sliding zone 52.2 27.4 2250 Colluvial deposits 39.2 28.7 2250 Gravelly soil mixture 60.9 30.5 2300 Block stone layer 87.0 34.8 2400

[0068] Let the limit equilibrium safety factor calculated using the equivalent formula be equal to the limit equilibrium safety factor calculated using the original parameters, that is, F s = F′ s , then the calculation parameters equivalent to the seismic dynamic action can be obtained from the equivalent relationship. The obtained equivalent parameters can be used for the numerical simulation study of landslide surge under seismic dynamic action. The numerical simulation of landslide surge based on the equivalent parameters can effectively evaluate the landslide surge disaster induced by earthquakes, so as to carry out targeted prevention and control.

[0069] This solution designs a method for calculating the numerical parameters of landslide surge under seismic dynamic action by using the equivalent relationship of the limit equilibrium safety factor, and equivalent the seismic dynamic action to the weakening of mechanical parameters. By using the equivalent relationship between the landslide limit equilibrium states corresponding to the cases with and without seismic dynamic action, the corresponding relationship between the original parameters and the equivalent parameters is established, so as to determine the equivalent calculation parameters of landslide surge under seismic dynamic action, and equivalent the seismic dynamic action to the weakening of landslide parameters. This method has a simple process and strong operability, and can effectively solve the problem of difficult application of seismic dynamic action in the existing numerical simulation of landslide surge, and then effectively prevent the surge disaster under seismic dynamic action based on the numerical simulation of landslide surge.

[0070] The above are only the preferred embodiments of the present invention, but do not limit the patent scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing specific embodiments, or perform equivalent replacements for some of the technical features. Any equivalent structure made by using the content of the specification and drawings of the present invention, directly or indirectly applied in other related technical fields, is similarly within the scope of the patent protection of the present invention.

Claims

1. A method for determining equivalent calculation parameters of landslide surge under seismic dynamic action, characterized in that: For the target landslide area, the following steps are performed to obtain the equivalent calculation parameters of landslide surge for each preset type of soil layer in the target landslide area under seismic dynamic action, which are used for numerical simulation calculation of landslide surge in the target landslide area under seismic dynamic action: Step A: For the target landslide area, obtain the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force. Step B: For the target landslide area, divide the soil layer of the target landslide area vertically and equally into a preset number of strip-shaped soil blocks along the horizontal direction corresponding to the highest point to the lowest point of the landslide, and establish a landslide strip division model of the target landslide area. Step C: Based on the landslide strip division model of the target landslide area, the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force, and combined with the seismic acceleration of the preset target landslide area, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action. Step D: Based on the limit equilibrium safety factor of the target landslide area under seismic dynamic action, and combined with the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force, obtain the equivalent calculation parameters of landslide surge for each preset type of soil layer in the target landslide area under seismic dynamic action. In the above Step D, through the following process, obtain the equivalent calculation parameters of landslide surge for each preset type of soil layer in the target landslide area under seismic dynamic action: Step D1: Through the following formula, construct an equivalent formula for the limit equilibrium safety factor: where F′ s represents the equivalent parameter of the limit equilibrium safety factor of the target landslide area under seismic dynamic action; c′ i represents the equivalent parameter of the cohesion of the soil layer of the preset type in the target landslide area under seismic dynamic action; represents the equivalent parameter of the internal friction angle of the soil layer of the preset type in the target landslide area under seismic dynamic action; l i represents the arc length of the bottom surface of the strip soil block i; W i represents the self-weight of the strip soil block i; N i represents the normal reaction force on the bottom surface of the strip soil block i; d i represents the bottom slope angle of the strip soil block i; I represents the total number of preset strip soil blocks; s represents the preset type of soil layer, and S represents the total number of preset type of soil layers; Step D2: The cohesion and internal friction angle of each preset type of soil layer in the target landslide area under no external force are iteratively and proportionally weakened to obtain c′ i and The c′ obtained in each iteration i and are substituted into the equivalent formula to obtain F′ s , until F′ s is equal to the limit equilibrium safety factor of the target landslide area under seismic dynamic action, the iteration ends, and F′ s and the corresponding c′ of each preset type of soil layer when it is equal to the limit equilibrium safety factor of the target landslide area under seismic dynamic action i and are used as the equivalent calculation parameters of the landslide surge of this preset type of soil layer in the target landslide area under seismic dynamic action.

2. The method for determining equivalent calculation parameters of landslide surge under seismic dynamic action according to claim 1, wherein: In the above Step C, specifically through the following steps, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action: Step C1: Based on the landslide strip division model of the target landslide area, and combined with the seismic acceleration of the preset target landslide area, obtain the horizontal seismic load of each strip-shaped soil block in the target landslide area under seismic dynamic action. Step C2: Based on the horizontal seismic load of each strip-shaped soil block, obtain the vertical seismic load of each strip-shaped soil block under seismic dynamic action. Step C3: Based on the horizontal seismic load and vertical seismic load of each strip-shaped soil block, combined with the landslide strip division model of the target landslide area and the cohesion and internal friction angle of each preset type of soil layer in the target landslide area without external force, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action.

3. The method for determining equivalent calculation parameters of landslide surge under seismic dynamic action according to claim 2, wherein: In the above Step C1, for each strip-shaped soil block respectively, through the following formula, obtain the horizontal seismic load of this strip-shaped soil block under seismic dynamic action, and then obtain the horizontal seismic load of each strip-shaped soil block under seismic dynamic action: F hi = α w W i a i In the formula, F hi represents the horizontal seismic load of the strip soil layer block i; α w represents the comprehensive horizontal seismic coefficient, a h represents the seismic acceleration of the preset target landslide area; ξ represents the preset reduction coefficient; g represents the acceleration of gravity; W i represents the self-gravity of the strip soil layer block i; a i represents the dynamic distribution coefficient of the strip soil layer block i.

4. The method for determining equivalent calculation parameters of landslide surge under seismic dynamic action according to claim 2, wherein: In the above Step C2, for each strip-shaped soil block respectively, through the following formula, obtain the vertical seismic load of this strip-shaped soil block under seismic dynamic action, and then obtain the vertical seismic load of each strip-shaped soil block under seismic dynamic action: F vi = F hi / 3 In the formula, F vi represents the vertical seismic load of the strip soil layer block i; F hi represents the horizontal seismic load of the strip soil layer block i.

5. The method for determining equivalent calculation parameters of landslide surge under seismic dynamic action according to claim 2, characterized in that: In the above Step C3, through the following formula, obtain the limit equilibrium safety factor of the target landslide area under seismic dynamic action: where c i represents the cohesion of the preset type of soil layer without external force; represents the internal friction angle of the preset type of soil layer without external force; W i represents the self-weight of the strip soil mass i; N i represents the normal reaction force on the bottom surface of the strip soil mass i; d i represents the bottom slope angle of the strip soil mass i; l i represents the arc length of the bottom surface of the strip soil mass i; F vi represents the vertical seismic load of the strip soil mass i under seismic dynamic action; F hi represents the horizontal seismic load of the strip soil mass i under seismic dynamic action; F s represents the limit equilibrium safety factor of the target landslide area under seismic dynamic action; I represents the total number of preset strip soil masses; s represents the preset type of soil layer, and S represents the total number of preset types of soil layers.

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