Landslide surge induced glacial lake outburst flood disaster chain numerical simulation method

Abstract

The invention discloses a numerical simulation method for a landslide surge induced glacial lake outburst flood disaster chain, which comprises the following steps of: coupling a depth average mixed flow model of four-phase media of water, coarse particles, fine particles and a gas phase on the basis of a continuous medium mechanical method, and acquiring data required by the numerical simulation method. According to the method, a continuous medium mechanics theory is combined, a continuous medium mechanics method is coupled with a depth average mixed flow model of four-phase media including water, coarse particles, fine particles and a gas phase, and a finite difference method is adopted to realize numerical simulation of a landslide surge induced glacial lake outburst flood disaster chain. According to the numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain, the coupling of the whole process of the glacial lake outburst disaster chain from landslide movement to induction of surge by landslide into the lake and then induction of glacial lake outburst by surge and flood routing is comprehensively considered, and the whole-process simulation of the landslide-induced glacial lake outburst flood disaster chain is successfully realized; and technical support is provided for the field of glacial lake outburst.

Description

Technical Field

[0001] The invention belongs to the technical field of glacial lake outburst, and in particular relates to a numerical simulation method for a glacial lake outburst flood disaster chain induced by landslide surge. Background Art

[0002] Glacial lake outburst is a common natural disaster in alpine areas. The retreat of glaciers in alpine areas will form moraine lakes at the front edge of the glaciers. There are often a large number of landslides distributed around these alpine glacial lakes. After the landslides enter the lake, they have a strong impact on the lake water, thus inducing surges. When the surge reaches the moraine dam, the moraine dam is eroded by the surge, and the moraine dam is cut open by the surge, and the glacial lake begins to burst. Once the glacial lake bursts, the outburst flood will pose a serious threat to the infrastructure and lives of residents downstream of the glacial lake. At present, there is no full-process coupled numerical simulation method for this type of glacial lake outburst disaster chain. Summary of the invention

[0003] The purpose of the present invention is to provide a numerical simulation method for a landslide surge-induced glacial lake outburst flood disaster chain, so as to solve the problem that there is currently no full-process coupled numerical simulation method for the glacial lake outburst flood disaster chain.

[0004] The embodiment of the present application is implemented as follows: a numerical simulation method for a glacial lake outburst flood disaster chain induced by landslide surges includes: based on a continuous medium mechanics method, coupling a depth-averaged mixed flow model of a four-phase medium of water, coarse particles, fine particles and gas phase, obtaining data required for the numerical simulation method, the data including terrain data, the location of the landslide initiation, the volume and depth information of the landslide initiation, the initial coarse and fine particle content of the landslide, the friction angle between the landslide and the bottom bed, the coarse and fine particle content of the landslide in the erodible channel, the glacial lake water depth distribution, the bottom roughness coefficient of surge and flood evolution, the coarse and fine particle content of the moraine dam, and at least one of the characteristic particle size of the coarse particles and the characteristic particle size of the fine particles of the moraine dam.

[0005] In some embodiments, the mixed flow motion control equation of the depth average mixed flow model is: ; ; ; In the formula, is the mixed flow density, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow center Directional bed resistance, unit: ; is the mixed flow depth, unit: ; The elevation of the terrain required for numerical simulation, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the total erosion rate of the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s.

[0006] In some embodiments, the transport equations for water, fine particulate matter, coarse particulate matter, and gas phase in the mixed flow are: ; ; ; ; In the formula, is the mixed flow depth, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; is the water phase erosion rate during the mixed flow movement, unit: ; is the erosion rate of fine particles in the mixed flow process, unit: ; is the erosion rate of coarse particles in the mixed flow process, unit: ; is the air erosion rate during the mixed flow movement, unit: ; Air escape rate in mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s.

[0007] In some embodiments, the evolution equation of the terrain is: ; In the formula, The elevation of the terrain required for numerical simulation, unit: ; is the total erosion rate of the mixed flow, unit: ; t is time, unit: s.

[0008] In some embodiments, the expression for the mixed flow density is: ; In the formula, is the mixed flow density, unit: ; , is the density of clean water, unit: ; , is the density of coarse and fine particles, unit: ; , is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

[0009] In some embodiments, the expressions for the bed resistance of the mixed flow along the x-direction and the y-direction are: ; ; Where: is the mixed flow density, unit: ; It is the conversion parameter when floods transition to underwater saturated landslides or debris flows, unit: dimensionless; Mixed flow edge Directional bed resistance, unit: ; Mixed flow center Directional bed resistance, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the x direction, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the y direction, unit: ; For along The drag force of coarse particles in directional mixed flow, unit: ; For along The drag force of coarse particles in directional mixed flow, unit: ; , is the acceleration due to gravity, unit: ; is the Manning coefficient, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: .

[0010] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; The expression of the conversion parameter when the flood transitions to underwater saturated landslide or debris flow is: ; In the formula, It is the conversion parameter when floods transition to underwater saturated landslides or debris flows, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; ϕ g_c is the critical total particulate matter concentration that separates underwater saturated landslide or debris flow from flood, unit: dimensionless, value is 0.18; It is the attenuation parameter when the flood transitions to underwater saturated landslide or debris flow, unit: dimensionless unit, the value is 13.8; Fine particulate matter, water and gas mixture along x Direction and y The motion resistance in the directions are: ; and ; Where: is the resistance to the movement of fine particles, water and gas mixture along the x direction, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the y direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; , is the density of clean water, unit: ; , is the density of coarse and fine particles, unit: ; , is the density of air, unit: ; is the suction stress between unsaturated fine particles, unit: ; is the friction angle between the unsaturated fine particles and the bottom bed in the mixed flow, unit: °; is the cohesion of unsaturated fine particles, unit: ; , , , , are empirical coefficients; It is the resistance conversion parameter from unsaturated landslide to saturated landslide, dimensionless.

[0011] In some embodiments, the unsaturated landslide to saturated landslide resistance conversion parameter The expression is: ; In the formula, is the transformation parameter of unsaturated landslide resistance to saturated landslide, dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; is the critical volume fraction of the gas phase when the landslide is designated as saturated by the present invention, with a value of 0.001, unit: dimensionless; is the attenuation parameter of the transformation of unsaturated landslide resistance to saturated landslide, unit: dimensionless value, the value is 13.8; Suction stress between unsaturated fine particles The expression is: ; In the formula, is the suction stress between unsaturated fine particles, unit: ; , All are empirical coefficients for calculating suction stress, unit: dimensionless; is the volumetric moisture content between fine particles, unit: dimensionless; is the residual moisture content between fine particles, unit: dimensionless; is the saturated moisture content between fine particles, unit: dimensionless; for , unit: dimensionless; Volume moisture content between fine particles The expression is: ; In the formula, is the volumetric moisture content between fine particles, unit: dimensionless; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

[0012] In some embodiments, the movement resistance of the coarse particles in the mixed flow along the x-direction and the y-direction are: ; ; In the formula, The coarse particles in the mixed flow The resistance to motion in the direction, in units: ; The coarse particles in the mixed flow The resistance to motion in the direction, in units: ; is the mixed flow density, unit: ; Density of a mixture of fine particles, water and gas, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; Mixed flow bottom edge Slope of direction, unit:°; The bottom edge of the debris flow Slope of direction, unit:°; is the friction angle between coarse particles and the bottom bed in the mixed flow, unit: °; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the turbulence coefficient of coarse particles in the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; , is the density of fine particulate matter, unit: ; Density of a mixture of fine particles, water and gas The expression is: ; In the formula, Density of a mixture of fine particles, water and gas, unit: ; , is the density of clean water, unit: ; , is the density of fine particulate matter, unit: ; , is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

[0013] In some embodiments, the total erosion rate of the mixed flow The expression is: ; In the formula, is the total erosion rate of the mixed flow, unit: ; is the mixed flow depth, unit: ; is the mixed flow density, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; Mixed flow edge Directional single width flow, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; , is the acceleration due to gravity, unit: ; It is the ratio of the pore water pressure to the total pressure in the bed granular material, unit: dimensionless parameter; , is the slope of the mixed flow channel bed, unit: °; For the bottom edge of the bed Slope of direction, unit:°; For the bottom edge of the bed Slope of direction, unit:°; is the friction angle of bed granular material, unit: °; is the cohesion of the bed granular material, unit: ; For the number ( ) grid's terrain elevation, in units: ; For the number ( ) grid's terrain elevation, in units: ; For the number ( ) grid's terrain elevation, in units: ; For terrain Grid size in direction, unit: ; For terrain Grid size in direction, unit: .

[0014] In some embodiments, the expressions for the erosion rates of the water phase, gas phase, fine particle phase, and coarse particle phase in the mixed flow are: ; In the formula, is the total erosion rate of the mixed flow, unit: ; Is the gas phase erosion rate during the mixed flow movement, unit: ; is the erosion rate of fine particles in the mixed flow process, unit: ; is the erosion rate of coarse particles in the mixed flow process, unit: ; is the erosion rate of the water phase during the mixed flow movement, unit: ; is the volume fraction of the gas phase in the erodible gully bed, unit: dimensionless; is the volume fraction of fine-grained material in the erodible gully bed, unit: dimensionless; is the volume fraction of coarse-grained material in the erodible gully bed, unit: dimensionless; is the volume fraction of the water phase in the erodible gully bed, unit: dimensionless.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: This application combines the theory of continuum mechanics, couples the depth average mixed flow model of water, coarse particles, fine particles and gas phase four-phase media through the continuum mechanics method, and uses the finite difference method to realize the numerical simulation of the landslide surge-induced glacial lake outburst flood disaster chain. The numerical simulation method of the landslide surge-induced glacial lake outburst flood disaster chain in this application comprehensively considers the coupling of the entire process of the glacial lake outburst disaster chain from landslide movement to landslide entering the lake induced surge to surge-induced glacial lake outburst and flood evolution, and successfully realizes the simulation of the entire process of the landslide-induced glacial lake outburst flood disaster chain, providing technical support for the field of glacial lake outburst. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the simulation result of glacial lake outburst induced by landslide surge in a gully in the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] The technical solution of this application is as follows: See also Figure 1The embodiment of the present application provides a numerical simulation method for a landslide surge-induced glacial lake outburst flood disaster chain, comprising: coupling a depth-averaged mixed flow model of a four-phase medium of water, coarse particles, fine particles and gas based on a continuous medium mechanics method, and obtaining data required for the numerical simulation method, wherein the data include terrain data, the location of the landslide initiation, the volume and depth information of the landslide initiation, the initial coarse and fine particle content of the landslide, the friction angle between the landslide and the bottom bed, the coarse and fine particle content of the landslide in the erodible channel, the glacial lake water depth distribution, the bottom bed roughness coefficient of surge and flood evolution, the coarse and fine particle content of the moraine dam, and at least one of the characteristic particle size of the coarse particles and the characteristic particle size of the fine particles of the moraine dam.

[0019] This application combines the theory of continuum mechanics, couples the depth average mixed flow model of water, coarse particles, fine particles and gas phase four-phase media through the continuum mechanics method, and uses the finite difference method to realize the numerical simulation of the landslide surge-induced glacial lake outburst flood disaster chain. The numerical simulation method of the landslide surge-induced glacial lake outburst flood disaster chain in this application comprehensively considers the coupling of the entire process of the glacial lake outburst disaster chain from landslide movement to landslide entering the lake induced surge to surge-induced glacial lake outburst and flood evolution, and successfully realizes the simulation of the entire process of the landslide-induced glacial lake outburst flood disaster chain, providing technical support for the field of glacial lake outburst.

[0020] In some embodiments, the mixed flow motion control equation of the depth average mixed flow model is: ; ; ; In the formula, is the mixed flow density, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow center Directional bed resistance, unit: ; is the mixed flow depth, unit: ; The elevation of the terrain required for numerical simulation, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the total erosion rate of the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s; In some embodiments, the transport equations for water, fine particulate matter, coarse particulate matter, and gas phase in the mixed flow are: ; ; ; ; In the formula, is the mixed flow depth, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; is the water phase erosion rate during the mixed flow movement, unit: ; is the erosion rate of fine particles in the mixed flow process, unit: ; is the erosion rate of coarse particles in the mixed flow process, unit: ; is the air erosion rate during the mixed flow movement, unit: ; Air escape rate in mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s; In some embodiments, the evolution equation of the terrain is: ; In the formula, The elevation of the terrain required for numerical simulation, unit: ; is the total erosion rate of the mixed flow, unit: ; t is time, unit: s.

[0021] In some embodiments, the expression for the mixed flow density is: ; In the formula, is the mixed flow density, unit: ; , is the density of clean water, unit: ; , is the density of coarse and fine particles, unit: ; , is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

[0022] In some embodiments, the expressions for the bed resistance of the mixed flow along the x-direction and the y-direction are: ; ; Where: is the mixed flow density, unit: ; It is the conversion parameter when floods transition to underwater saturated landslides or debris flows, unit: dimensionless; Mixed flow edge Directional bed resistance, unit: ; Mixed flow center Directional bed resistance, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the x direction, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the y direction, unit: ; For along The drag force of coarse particles in directional mixed flow, unit: ; For along The drag force of coarse particles in directional mixed flow, unit: ; , is the acceleration due to gravity, unit: ; is the Manning coefficient, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless.

[0023] Furthermore, the expression of the conversion parameter when the flood transitions to underwater saturated landslide or debris flow is: ; In the formula, It is the conversion parameter when floods transition to underwater saturated landslides or debris flows, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; ϕ g_c is the critical total particulate matter concentration that separates underwater saturated landslide or debris flow from flood, unit: dimensionless, value is 0.18; It is the attenuation parameter when the flood transitions to underwater saturated landslide or debris flow, unit: dimensionless unit, the value is 13.8; Understandably, when =0.18, representing the conversion parameter of flood Equal to 10 -6 ,when When the value is greater than 0.18, the movement resistance degenerates into the movement resistance of underwater saturated landslide (or debris flow), that is, the bed resistance of the mixed flow along the x and y directions is and From this we can calculate The value of is taken as 13.8.

[0024] Further, the fine particulate matter, water and gas mixture along x Direction and y The motion resistance in the directions are: ; and ; Where: is the resistance to the movement of fine particles, water and gas mixture along the x direction, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the y direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; , is the density of clean water, unit: ; , is the density of coarse and fine particles, unit: ; , is the density of air, unit: ; is the suction stress between unsaturated fine particles, unit: ; is the friction angle between the unsaturated fine particles and the bottom bed in the mixed flow, unit: °; is the cohesion of unsaturated fine particles, unit: ; , , , , are empirical coefficients; It is the resistance conversion parameter from unsaturated landslide to saturated landslide, dimensionless.

[0025] Furthermore, the unsaturated to saturated landslide resistance conversion parameter The expression is: ; In the formula, is the transformation parameter of unsaturated landslide resistance to saturated landslide, dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; It is the critical volume fraction of the gas phase when the landslide is designated as saturated by the present invention, with a value of 0.001, and the unit is dimensionless.

[0026] is the attenuation parameter of the transformation of unsaturated landslide resistance to saturated landslide, unit: dimensionless value, the value is 13.8; It can be understood that when the gas phase volume fraction =0.001, represents the resistance conversion parameter from unsaturated landslide to saturated landslide Equal to 10 -6 , gas phase volume fraction When it is greater than 0.001, the movement resistance degenerates into the movement resistance of unsaturated landslide (or debris flow), that is, the mixture of fine particles, water and gas phase along the x Direction and y The motion resistance in the directions are and , from which we can calculate The value of is taken as 13.8.

[0027] Furthermore, the adsorption stress between unsaturated fine particles The expression is: ; In the formula, is the suction stress between unsaturated fine particles, unit: ; , All are empirical coefficients for calculating suction stress, unit: dimensionless; is the volumetric moisture content between fine particles, unit: dimensionless; is the residual moisture content between fine particles, unit: dimensionless; is the saturated moisture content between fine particles, unit: dimensionless; for , unit: dimensionless.

[0028] Understandably, , It is obtained from experiments on unsaturated soil.

[0029] Furthermore, the volumetric water content between fine particles The expression is: ; In the formula, is the volumetric moisture content between fine particles, unit: dimensionless; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

[0030] Furthermore, the motion resistance of coarse particles in the mixed flow along the x-direction and the y-direction are: ; ; In the formula, The coarse particles in the mixed flow The resistance to motion in the direction, in units: ; The coarse particles in the mixed flow The resistance to motion in the direction, in units: ; is the mixed flow density, unit: ; Density of a mixture of fine particles, water and gas, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; Mixed flow bottom edge Slope of direction, unit:°; The bottom edge of the debris flow Slope of direction, unit:°; is the friction angle between coarse particles and the bottom bed in the mixed flow, unit: °; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the turbulence coefficient of coarse particles in the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; , is the density of fine particulate matter, unit: .

[0031] Furthermore, the density of the mixture of fine particles, water and gas is The expression is: ; In the formula, Density of a mixture of fine particles, water and gas, unit: ; , is the density of clean water, unit: ; , is the density of fine particulate matter, unit: ; , is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

[0032] Furthermore, the total erosion rate of the mixed flow The expression is: ; In the formula, is the total erosion rate of the mixed flow, unit: ; is the mixed flow depth, unit: ; is the mixed flow density, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; Mixed flow edge Directional single width flow, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; , is the acceleration due to gravity, unit: ; It is the ratio of the pore water pressure to the total pressure in the bed granular material, unit: dimensionless parameter; , is the slope of the mixed flow channel bed, unit: °; For the bottom edge of the bed Slope of direction, unit:°; For the bottom edge of the bed Slope of direction, unit:°; is the friction angle of bed granular material, unit: °; is the cohesion of the bed granular material, unit: ; For the number ( ) grid's terrain elevation, in units: ; For the number ( ) grid's terrain elevation, in units: ; For the number ( ) grid's terrain elevation, in units: ; For terrain Grid size in direction, unit: ; For terrain Grid size in direction, unit: .

[0033] Furthermore, the expressions for the erosion rates of water phase, gas phase, fine particle phase and coarse particle phase in the mixed flow are: ; In the formula, is the total erosion rate of the mixed flow, unit: ; Is the gas phase erosion rate during the mixed flow movement, unit: ; is the erosion rate of fine particles in the mixed flow process, unit: ; is the erosion rate of coarse particles in the mixed flow process, unit: ; is the erosion rate of the water phase during the mixed flow movement, unit: ; is the volume fraction of the gas phase in the erodible gully bed, unit: dimensionless; is the volume fraction of fine-grained material in the erodible gully bed, unit: dimensionless; is the volume fraction of coarse-grained material in the erodible gully bed, unit: dimensionless; is the volume fraction of the water phase in the erodible gully bed, unit: dimensionless.

[0034] Experimental example The landslide in a gully is about 150 m long, 70 m wide, 60 m thick, and has a volume of about 1.1 million m³. There is an ice lake downstream of the landslide, and the drop from the landslide to the surface of the ice lake is about 240 m. The initial coarse particle volume fraction of the landslide body is 35%, the initial fine particle volume fraction is 25%, and the initial water volume fraction is 5%. The friction angle between the coarse particle material and the bottom bed in the mixed flow is 30°, the friction angle between the unsaturated fine particle material and the bottom bed in the mixed flow is 25°, and the empirical coefficient of suction stress is =0.1, empirical coefficient for suction stress =0.8, the turbulence coefficient of coarse particles is 30.0 The Manning roughness coefficient of the outburst flood is 0.05 ; The air overflow rate in the mixed flow is 0.05 , the volume fraction of the gas phase in the erodible trench bed is 0.15; the volume fraction of fine particles in the erodible gully bed is 0.24; the volume fraction of coarse particles in the erodible gully bed is 0.36; the volume fraction of coarse particles in the erodible gully bed is 0.25; the empirical rheological coefficient of liquid slurry is , , , , the ratio of the pore water pressure to the total pressure in the bed granular material is 0.8 (unit: dimensionless parameter), the friction angle of the bottom bed granular material The value is 32°, the cohesion of the bottom granular material The value is 12500 , the terrain is The grid size in the direction is 12.5m, and the terrain is The grid size in the direction is 12.5m, and the clear water density is , the density of coarse and fine particles , the density of air The above parameters are input into the depth average mixed flow model for calculation, and the dynamic distribution results of landslide depth and glacial lake flood depth at different times are obtained. The results are as follows: Figure 1 shown.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Numerical simulation method of landslide surge-induced glacial lake outburst flood disaster chain, characterized by: include: Based on the continuum mechanics method, a depth-averaged mixed flow model of four-phase media including water, coarse particles, fine particles and gas is coupled to obtain the data required for the numerical simulation method, which includes terrain data, the location of landslide initiation, the volume and depth information of landslide initiation, the initial coarse and fine particle content of the landslide, the friction angle between the landslide and the bottom bed, the coarse and fine particle content of the landslide in the erodible channel, the distribution of glacial lake water depth, the bottom roughness coefficient of surge and flood evolution, the coarse and fine particle content of the moraine dam, and at least one of the characteristic particle size of the coarse particles and the characteristic particle size of the fine particles of the moraine dam.

2. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 1 is characterized in that: The mixed flow motion control equation of the depth average mixed flow model is: ； ； ； In the formula, is the mixed flow density, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow center Directional bed resistance, unit: ; is the mixed flow depth, unit: ; The elevation of the terrain required for numerical simulation, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the total erosion rate of the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s.

3. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 2 is characterized in that: In mixed flow, the transport equations for water, fine particles, coarse particles, and gas are: ； ； ； ； In the formula, is the mixed flow depth, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; is the water phase erosion rate during the mixed flow movement, unit: ; is the erosion rate of fine particles in the mixed flow process, unit: ; is the erosion rate of coarse particles in the mixed flow process, unit: ; is the air erosion rate during the mixed flow movement, unit: ; Air escape rate in mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s.

4. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 2 is characterized in that: The evolution equation of the terrain is: ； In the formula, The elevation of the terrain required for numerical simulation, unit: ; is the total erosion rate of the mixed flow, unit: ; t is time, unit: s.

5. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 2 is characterized in that: The expression of mixed flow density is: ； In the formula, is the mixed flow density, unit: ; , is the density of clean water, unit: ; , is the density of coarse and fine particles, unit: ; , is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

6. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 2 is characterized in that: The expressions of the bed resistance of mixed flow along the x and y directions are: ； ； Where: is the mixed flow density, unit: ; It is the conversion parameter when floods transition to underwater saturated landslides or debris flows, unit: dimensionless; Mixed flow edge Directional bed resistance, unit: ; Mixed flow center Directional bed resistance, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the x direction, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the y direction, unit: ; For along The drag force of coarse particles in directional mixed flow, unit: ; For along The drag force of coarse particles in directional mixed flow, unit: ; , is the acceleration due to gravity, unit: ; is the Manning coefficient, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; , for the mixed flow Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; The expression of the conversion parameter when the flood transitions to underwater saturated landslide or debris flow is: ； In the formula, It is the conversion parameter when floods transition to underwater saturated landslides or debris flows, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; ϕ g_c is the critical total particulate matter concentration that separates underwater saturated landslide or debris flow from flood, unit: dimensionless, value is 0.18; It is the attenuation parameter when the flood transitions to underwater saturated landslide or debris flow, unit: dimensionless unit, the value is 13.8; Fine particulate matter, water and gas mixture along x Direction and y The motion resistance in the directions are: ； and ； Where: is the resistance to the movement of fine particles, water and gas mixture along the x direction, unit: ; is the resistance to the movement of fine particles, water and gas mixture along the y direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; , is the density of clean water, unit: ; , is the density of coarse and fine particles, unit: ; , is the density of air, unit: ; is the suction stress between unsaturated fine particles, unit: ; is the friction angle between the unsaturated fine particles and the bottom bed in the mixed flow, unit: °; is the cohesion of unsaturated fine particles, unit: ; , , , , are empirical coefficients; It is the resistance conversion parameter from unsaturated landslide to saturated landslide, dimensionless.

7. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 6 is characterized in that: Resistance conversion parameters from unsaturated landslide to saturated landslide The expression is: ； In the formula, is the transformation parameter of unsaturated landslide resistance to saturated landslide, dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; is the critical volume fraction of the gas phase when the landslide is designated as saturated by the present invention, with a value of 0.001, unit: dimensionless; is the attenuation parameter of the transformation of unsaturated landslide resistance to saturated landslide, unit: dimensionless value, the value is 13.8; Suction stress between unsaturated fine particles The expression is: ； In the formula, is the suction stress between unsaturated fine particles, unit: ; , All are empirical coefficients for calculating suction stress, unit: dimensionless; is the volumetric moisture content between fine particles, unit: dimensionless; is the residual moisture content between fine particles, unit: dimensionless; is the saturated moisture content between fine particles, unit: dimensionless; for , unit: dimensionless; Volume moisture content between fine particles The expression is: ； In the formula, is the volumetric moisture content between fine particles, unit: dimensionless; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

8. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 6 is characterized in that: The motion resistance of coarse particles in the mixed flow along the x-direction and y-direction are: ； ； In the formula, The coarse particles in the mixed flow The resistance to motion in the direction, in units: ; The coarse particles in the mixed flow The resistance to motion in the direction, in units: ; is the mixed flow density, unit: ; Density of a mixture of fine particles, water and gas, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; is the mixed flow depth, unit: ; Mixed flow bottom edge Slope of direction, unit:°; The bottom edge of the debris flow Slope of direction, unit:°; is the friction angle between coarse particles and the bottom bed in the mixed flow, unit: °; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the turbulence coefficient of coarse particles in the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; , is the density of fine particulate matter, unit: ; Density of a mixture of fine particles, water and gas The expression is: ； In the formula, Density of a mixture of fine particles, water and gas, unit: ; , is the density of clean water, unit: ; , is the density of fine particulate matter, unit: ; , is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

9. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 8 is characterized in that: Total erosion rate of mixed flow The expression is: ； In the formula, is the total erosion rate of the mixed flow, unit: ; is the mixed flow depth, unit: ; is the mixed flow density, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow edge Directional bed resistance, unit: ; Mixed flow edge Directional flow velocity, unit: ; Mixed flow edge Flow velocity in direction, unit: ; Mixed flow edge Directional single width flow, unit: ; Mixed flow edge Single-width flow in a direction, unit: ; , is the acceleration due to gravity, unit: ; It is the ratio of the pore water pressure to the total pressure in the bed granular material, unit: dimensionless parameter; , is the slope of the mixed flow channel bed, unit: °; For the bottom edge of the bed Slope of direction, unit:°; For the bottom edge of the bed Slope of direction, unit:°; is the friction angle of bed granular material, unit: °; is the cohesion of the bed granular material, unit: ; For the number ( ) grid's terrain elevation, in units: ; For the number ( ) grid's terrain elevation, in units: ; For the number ( ) grid's terrain elevation, in units: ; For terrain Grid size in direction, unit: ; For terrain Grid size in direction, unit: .

10. The numerical simulation method for the landslide surge-induced glacial lake outburst flood disaster chain according to claim 9 is characterized in that: The expressions for the erosion rates of water phase, gas phase, fine particle phase and coarse particle phase in mixed flow are: ； In the formula, is the total erosion rate of the mixed flow, unit: ; Is the gas phase erosion rate during the mixed flow movement, unit: ; is the erosion rate of fine particles in the mixed flow process, unit: ; is the erosion rate of coarse particles in the mixed flow process, unit: ; is the erosion rate of the water phase during the mixed flow movement, unit: ; is the volume fraction of the gas phase in the erodible gully bed, unit: dimensionless; is the volume fraction of fine-grained material in the erodible gully bed, unit: dimensionless; is the volume fraction of coarse-grained material in the erodible gully bed, unit: dimensionless; is the volume fraction of the water phase in the erodible gully bed, unit: dimensionless.

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