A method, system and electronic equipment for evaluating linear wave-induced seabed shear failure based on LRBFCM type meshless method

Abstract

The present invention discloses a method for assessing linear wave-induced seabed shear failure based on the LRBFCM method, comprising the following steps: collecting characteristic parameters of seabed overlying wave loads and seabed soil parameters; using linear wave analytical solutions combined with wave load characteristic parameters to calculate the seabed surface hydrodynamic pressure; establishing a seabed model, combining the seabed surface hydrodynamic pressure and seabed soil parameters to calculate the seabed dynamic response information under the action of waves; and judging the shear failure area of ​​the seabed soil using the Moore-Coulomb criterion according to the seabed dynamic response information. The present invention uses the LRBFCM method, which is much more efficient than the traditional grid-based numerical method, has fast calculation speed, high solution accuracy, and can meet engineering needs.

Description

Technical Field

[0001] The present invention belongs to the technical field of seabed soil liquefaction analysis, and specifically relates to a linear wave-induced seabed shear failure assessment method, system and electronic equipment based on an LRBFCM type gridless method. Background Art

[0002] In the field of ports, coasts and offshore engineering, seabed stability is a key factor in the stability of marine structure foundations. Under the action of wave loads, the effective stress between particles of seabed soil, as a solid-liquid two-phase porous medium material, changes, causing changes in soil strength. The main form of failure is shear failure. Once shear failure occurs, the stability of the engineering structure is threatened.

[0003] There are generally two methods for evaluating the shear failure of seabed soil, one is to evaluate through analytical solutions, and the other is to use numerical simulation methods. The analytical solution evaluation method has a limited scope of application and cannot accurately evaluate the stability of the seabed around the foundations of different structures. The numerical evaluation method can be adapted to various foundations, but the traditional mesh method (such as the finite element method) requires a lot of time and computational costs to generate the mesh, so the evaluation speed is relatively slow.

[0004] In order to solve the problem of high computational cost of traditional grid method, the present invention adopts Local Radial Basis Function Collocation Method (LRBFCM) to spatially discretize the computational domain. LRBFCM discretizes the computational domain into a set of scattered points to replace the grid, with high solution accuracy and good convergence, and eliminates the step of generating grids. It can accurately and quickly describe the dynamic response of the seabed under wave loads and perform shear failure assessment on the seabed soil. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a method, system and electronic equipment for assessing linear wave-induced seabed shear damage based on the LRBFCM method, aiming to solve the above-mentioned problems in the prior art.

[0006] The present invention is implemented by the following technical solutions:

[0007] The first aspect of the present invention provides a method for evaluating linear wave-induced seabed shear failure based on the LRBFCM method, comprising the following steps:

[0008] Collect characteristic parameters of seabed overlying wave loads and seabed soil parameters;

[0009] The dynamic water pressure on the seabed surface is calculated using the linear wave analytical solution combined with the characteristic parameters of wave loads;

[0010] Establish a seabed model and calculate the dynamic response information of the seabed under the action of waves by combining the dynamic water pressure on the seabed surface and the seabed soil parameters;

[0011] According to the dynamic response information of the seabed, the Mohr-Coulomb criterion is used to determine the shear failure area of ​​the seabed soil.

[0012] To optimize the above technical solutions, the specific measures taken also include:

[0013] Furthermore, the characteristic parameters of the overlying wave load include water depth h, wave height H, period T and wavelength L, and the seabed soil parameters include seabed thickness d, soil shear modulus G, soil density ρ s , soil saturation S r , soil permeability coefficient K s , soil porosity n s .

[0014] Furthermore, the linear wave analytical solution is combined with the characteristic parameters of wave load to calculate the dynamic water pressure on the seabed surface, specifically:

[0015] p b =p0×cos(kx-ωt)

[0016] p0=γ w H / (2cosh(kh))

[0017] k=2π / L

[0018]

[0019] Among them, p b is the dynamic water pressure on the seabed surface, p0 is the linear wave pressure amplitude, γ w is the unit weight of water, which is equal to 9.807 kN / m 3 The wave height H, the water depth h, and the wavelength L of the linear wave are obtained by on-site observation or consulting local historical data, k is the wave number of the linear wave, and ω is the angular velocity.

[0020] Furthermore, a seabed model is established, and the dynamic response information of the seabed under the action of waves is calculated by combining the dynamic water pressure on the seabed surface and the seabed soil parameters. Specifically:

[0021] Using the biot up equation as the governing equation for the seabed model,

[0022]

[0023] ρ f =1×10 3 kg / m 3

[0024] Among them: soil shear modulus G, soil permeability coefficient K s , soil porosity n s It is measured by the seabed soil sampling experiment, ρ f is the pore water density, p s is the pore water pressure, γ w is the unit weight of water, β s is the pore water compressibility coefficient, ε s is the volume strain, μ s is Poisson's ratio, u s , v s and w s are the displacements of the soil along the x, y, and z directions respectively;

[0025] The control equations are discretized in the computational domain using the LRBFCM method, a linear equation matrix about N scattered points is constructed, and the dynamic response of each point in the seabed at each time step is calculated, including pore water pressure and horizontal and vertical displacements.

[0026] [A] N×N [Φ] N×1 =[B] N×1 ,

[0027] [Φ] N×1 =[u1(y1),u1(y2),…,u1(y N ),u2(y1),u2(y2),…,u2(y N ),p(y1),p(y2),…,p(y N )] T

[0028] Where: [Φ] N×1 represents the dynamic response of each point, including displacement and pore water pressure, [B] N×1 A column vector of external loads representing the hydrodynamic pressure on the seabed surface, [A] N×N Represents a discretized sparse matrix;

[0029] The linear control equation matrix discretized by LRBFCM method is constructed by programming to obtain the seabed model;

[0030] According to the dynamic water pressure on the seabed surface, the seabed model is used to calculate the dynamic response information of the seabed under the action of waves. The dynamic response information of the seabed includes the soil skeleton displacement in the horizontal and vertical directions, and the pore water pressure.

[0031] Furthermore, according to the dynamic response information of the seabed, the Mohr-Coulomb criterion is used to determine the shear failure area of ​​the seabed soil, specifically:

[0032] Calculating seabed soil stress information according to seabed dynamic response information, wherein the seabed soil stress information includes effective stress and shear stress;

[0033] Calculate the actual internal friction angle based on the seabed soil stress information;

[0034] According to the actual internal friction angle and the Mohr-Coulomb criterion, the shear failure area of ​​the seabed soil is determined.

[0035] Furthermore, the seabed soil stress information is calculated based on the seabed dynamic response information, specifically:

[0036]

[0037] Where: σ′ x ,σ′ y and σ' z denote the effective stress along the x, y, and z directions, respectively, and τ xz , τ yz , τ xy represent the shear stress in three directions respectively.

[0038] Furthermore, the actual internal friction angle is calculated based on the seabed soil stress information, specifically:

[0039]

[0040]

[0041] Where: ψ is the actual internal friction angle, σ1, σ2 and σ3 represent the three principal stresses respectively, represents the polar coordinates in the π plane, s represents the vertical distance in the π plane, and J represents the third stress invariant.

[0042] Furthermore, the shear failure area of ​​the seabed soil is determined based on the actual internal friction angle and the Mohr-Coulomb criterion, specifically: ψ ≥ ψ f , the actual internal friction angle ψ and the critical internal friction angle ψ f When the actual internal friction angle ψ is greater than or equal to the set critical internal friction angle ψ, f Shear failure occurs.

[0043] The second aspect of the present invention provides a linear wave-induced seabed shear failure assessment system based on the LRBFCM method, comprising:

[0044] Collection module 1, used to collect wave load characteristic parameters;

[0045] Collection module 2, used to collect seabed parameters;

[0046] A calculation module for calculating the dynamic water pressure on the seabed surface using a linear wave analytical solution combined with wave load characteristic parameters;

[0047] Modeling module, used to establish a seabed model and calculate the dynamic response information of the seabed under the action of waves in combination with seabed soil parameters;

[0048] The analysis module is used to determine the shear failure area of ​​the seabed soil based on the dynamic response information of the seabed and the Moore-Coulomb criterion.

[0049] The third aspect of the present invention provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned linear wave-induced seabed shear damage assessment method based on the LRBFCM method.

[0050] Beneficial effects of the present invention:

[0051] Compared with the prior art, the linear wave-induced seabed shear failure assessment system based on the LRBFCM method of the present invention overcomes the shortcomings of traditional numerical methods that require a lot of time and computing cost for grid generation and division. It has high computational efficiency and fast speed, can effectively save computing space, and can calculate the seabed response and shear failure of wave loads applied to the seabed soil at any time period, which can provide a reference for the foundation stability assessment of near-coastal marine engineering structures and the site selection of offshore engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of a method for evaluating linear wave-induced seabed shear failure based on the LRBFCM method provided in the first embodiment of the present invention.

[0053] Figure 2 It is a detailed diagram of the process provided by the present invention.

[0054] Figure 3 It is a schematic diagram of the shear failure area of ​​the seabed soil of the present invention.

[0055] Figure 4 It is a schematic diagram of module connection provided by the second embodiment of the present invention.

[0056] Figure 5 It is a structural schematic diagram of an electronic device provided by the third embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to illustrate the technical solution and working principle of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0058] The present invention provides Figure 1-2 A linear wave-induced seabed shear failure assessment method based on the LRBFCM method is shown, comprising the following steps:

[0059] Step S1: Collecting characteristic parameters of seabed overlying wave loads and seabed soil parameters.

[0060] The characteristic parameters of the overlying wave load include water depth h, wave height H, period T and wavelength L. The seabed soil parameters include seabed thickness d, soil shear modulus G, soil density ρ s , soil saturation S r , soil permeability coefficient K s , soil porosity n s .

[0061] Step S2: Calculate the dynamic water pressure on the seabed surface using the linear wave analytical solution combined with the wave load characteristic parameters, specifically:

[0062] p b =p0×cos(kx-ωt)

[0063] p0=γ w H / (2cosh(kh))

[0064] k=2π / L

[0065]

[0066] Among them, p b is the dynamic water pressure on the seabed surface, p0 is the linear wave pressure amplitude, γ w is the unit weight of water, which is equal to 9.807 kN / m 3 The wave height H, the water depth h, and the wavelength L of the linear wave are obtained by on-site observation or consulting local historical data, k is the wave number of the linear wave, and ω is the angular velocity.

[0067] Step S3: Establish a seabed model and calculate the dynamic response information of the seabed under the action of waves by combining the dynamic water pressure on the seabed surface and the seabed soil parameters

[0068] S31: Use the biot up equation as the governing equation for the seabed model,

[0069]

[0070] ρ f=1×10 3 kg / m 3

[0071] Among them: soil shear modulus G, soil permeability coefficient K s , soil porosity n s It is measured by the seabed soil sampling experiment, ρ f is the pore water density, p s is the pore water pressure, γ w is the unit weight of water, β s is the pore water compressibility coefficient, ∈ s is the volume strain, μ s is Poisson's ratio, u s , v s and w s are the displacements of the soil along the x, y, and z directions respectively;

[0072] S32: Use the LRBFCM method to discretize the control equations in the computational domain, construct a linear equation matrix about N scattered points, and calculate the dynamic response of each point in the seabed at each time step. The dynamic response includes pore water pressure and horizontal and vertical displacements.

[0073] [A] N×N [Φ] N×1 =[B] N×1 ,

[0074] [Φ] N×1 =[u1(y1),u1(y2),…,u1(y N ),u2(y1),u2(y2),…,u2(y N ),p(y1),p(y2),…,p(y N )] T

[0075] Where: [Φ] N×1 represents the dynamic response of each point, including displacement and pore water pressure, [B] N×1 A column vector of external loads representing the hydrodynamic pressure on the seabed surface, [A] N×N Represents a discretized sparse matrix.

[0076] S33: Programming the linear control equation matrix discretized by the LRBFCM method to obtain a seabed model. In this embodiment, the programming is written in C++ language.

[0077] S34: According to the dynamic water pressure on the seabed surface, using the seabed model, the dynamic response information of the seabed under the action of waves is calculated, wherein the seabed dynamic response information includes soil skeleton displacement in the horizontal and vertical directions, and pore water pressure.

[0078] Step S4: According to the dynamic response information of the seabed, the shear failure area of ​​the seabed soil is determined using the Moore-Coulomb criterion.

[0079] S41: Calculate seabed soil stress information according to the seabed dynamic response information, wherein the seabed soil stress information includes effective stress and shear stress. The specific calculation formula is:

[0080]

[0081]

[0082] Where: σ′ x ,σ′ y and σ' z denote the effective stress along the x, y, and z directions, respectively, and τ xz , τ yz , τ xy represent the shear stress in three directions respectively.

[0083] S42: Calculate the actual internal friction angle based on the seabed soil stress information. The calculation formula is as follows:

[0084]

[0085] Where: ψ is the actual internal friction angle, σ1, σ2 and σ3 represent the three principal stresses respectively, represents the polar coordinates in the π plane, s represents the vertical distance in the π plane, and J represents the third stress invariant.

[0086] S43: Determine the shear failure area of ​​the seabed soil based on the actual internal friction angle and the Mohr-Coulomb criterion.

[0087] ψ ≥ ψ f

[0088] Where: f is the critical internal friction angle, ψ is the actual internal friction angle;

[0089] The actual internal friction angle is compared with the critical internal friction angle. When the actual internal friction angle is greater than or equal to the set critical internal friction angle, shear failure occurs.

[0090] The present invention discloses a method for rapidly evaluating linear wave-induced seabed shear damage under wave action based on a gridless method, which overcomes the shortcomings of traditional numerical methods that require a lot of time and computational cost for grid generation and division. It has high computational efficiency and fast speed, can effectively save computational space, and can provide a reference for foundation stability assessment of near-coast marine engineering structures and site selection of offshore engineering.

[0091] The step division of the above methods is only for the purpose of clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent. Specific embodiment:

[0093] Step 1: Determine the characteristics of the seabed overlying wave load, select the sea area with a water depth of 8m, a wave height of 3m, a period of 6s, and a wavelength of 45.2m, and calculate the dynamic water pressure on the seabed surface according to the above method.

[0094] Determine the seabed soil parameters, including: the seabed thickness d is 8m, the soil deformation modulus E is equal to 2.66*10 7 N / m 2 , soil density is 2650kg / m 3 , the soil saturation is 0.975, and the soil permeability coefficient K is equal to 1*10 -5 m / s, soil porosity 0.425, and soil parameters were obtained by on-site sampling exploration in the simulated area.

[0095] Step 2: Establish a seabed model based on the LRBFCM meshless method to calculate the dynamic response information of the seabed under the action of waves. The dynamic response information of the seabed includes the effective stress and shear stress in the horizontal and numerical directions.

[0096] Step 3: If Figure 2 The figure shows the schematic diagram of the shear failure area of ​​the seabed soil. Based on the effective stress and shear stress in the horizontal and numerical directions, the Moore-Coulomb criterion model is used to evaluate the shear failure risk of the seabed soil and estimate the seabed shear failure area. The calculation results show that when the time is 35 seconds, the actual internal friction angle at this time is equal to the set critical internal friction angle, and shear failure occurs in the seabed soil at this time.

[0097] Second embodiment

[0098] As shown in the figure, the second embodiment of the present invention provides a linear wave-induced seabed shear failure assessment system based on the LRBFCM method, which is characterized by: comprising:

[0099] A collection module 201 is used to collect wave load characteristic parameters;

[0100] The second acquisition module 202 is used to acquire seabed parameters;

[0101] A calculation module 203 is used to calculate the dynamic water pressure on the seabed surface using a linear wave analytical solution combined with wave load characteristic parameters;

[0102] Modeling module 204, used to establish a seabed model and calculate the dynamic response information of the seabed under the action of waves by combining the dynamic water pressure on the seabed surface and the seabed soil parameters;

[0103] Analysis module 205, used to determine the shear failure area of ​​the seabed soil according to the seabed dynamic response information using the Moore-Coulomb criterion

[0104] It is not difficult to find that this embodiment is a system embodiment corresponding to the first embodiment, and this embodiment can be implemented in conjunction with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the first embodiment.

[0105] It is worth mentioning that all modules involved in this embodiment are logic modules. In practical applications, a logic unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by the present invention, but this does not mean that there are no other units in this embodiment.

[0106] Third embodiment:

[0107] As shown in the figure, the third embodiment of the present invention provides an electronic device, comprising: at least one processor 301; and a memory 302 communicatively connected to the at least one processor 301; wherein the memory 302 stores instructions executable by the at least one processor 301, and the instructions are executed by the at least one processor 301 so that the at least one processor 301 can execute the above-mentioned linear wave-induced seabed shear damage assessment method based on the LRBFCM method.

[0108] The memory 302 and the processor 301 are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors 301 and the memory 302 together. The bus can also connect various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor 301 is transmitted on a wireless medium through an antenna, and further, the antenna also receives data and transmits the data to the processor 301.

[0109] The processor 301 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management and other control functions. The memory 302 can be used to store data used by the processor 301 when performing operations.

[0110] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A linear wave-induced seabed shear failure assessment method based on the LRBFCM type meshless method, characterized in that: The following steps are involved: Collect characteristic parameters of seabed overlying wave loads and seabed soil parameters; The characteristic parameters of the overlying wave load include water depth h, wave height H, period T and wavelength L. The seabed soil parameters include seabed thickness d, soil shear modulus G, soil density ρ s , soil saturation S r , soil permeability coefficient K s , soil porosity n s ; The dynamic water pressure on the seabed surface is calculated using the linear wave analytical solution combined with the characteristic parameters of wave loads, specifically: p b =p0×cos(kx-ωt) p0=γ w H / (2cosh(kh)) k=2π / L Among them, p b is the dynamic water pressure on the seabed surface, p0 is the linear wave pressure amplitude, γ w is the unit weight of water, k is the wave number of the linear wave, and ω is the angular velocity; A seabed model is established, and the dynamic response information of the seabed under the action of waves is calculated by combining the dynamic water pressure on the seabed surface and the seabed soil parameters. Specifically: Using the biot up equation as the governing equation for the seabed model, ρ f =1×10 3 kg / m 3 Where: f is the pore water density, p s is the pore water pressure, γ w is the unit weight of water, β s is the pore water compressibility coefficient, ∈ s is the volume strain, μ s is Poisson's ratio, u s , v s and w s are the displacements of the soil along the x, y, and z directions respectively; The control equations are discretized in the computational domain using the LRBFCM method, a linear control equation matrix about N scattered points is constructed, and the dynamic response of each point in the seabed at each time step is calculated, including pore water pressure and horizontal and vertical displacements. [A] N×N [F] N×1 =[B] N×1 , [Φ] N×1 =[u1(y1),u1(y2),…,u1(y N ),u2(y1),u2(y2),…,u2(y N ),p(y1),p(y2),…,p(y N )] T Where: [Φ] N×1 represents the dynamic response of each point, including displacement and pore water pressure, [B] N×1 A column vector of external loads representing the hydrodynamic pressure on the seabed surface, [A] N×N Represents a discretized sparse matrix; The linear control equation matrix discretized by LRBFCM method is constructed by programming to obtain the seabed model; According to the dynamic water pressure on the seabed surface, using the seabed model, the dynamic response information of the seabed under the action of waves is calculated, wherein the dynamic response information of the seabed includes soil skeleton displacement in the horizontal and vertical directions, and pore water pressure; According to the dynamic response information of the seabed, the Mohr-Coulomb criterion is used to determine the shear failure area of ​​the seabed soil.

2. A linear wave-induced seabed shear failure assessment method based on LRBFCM type meshless method according to claim 1, characterized in that: According to the dynamic response information of the seabed, the shear failure area of ​​the seabed soil is determined using the Moore-Coulomb criterion, specifically: Calculating seabed soil stress information according to seabed dynamic response information, wherein the seabed soil stress information includes effective stress and shear stress; Calculate the actual internal friction angle based on the seabed soil stress information; According to the actual internal friction angle and the Mohr-Coulomb criterion, the shear failure area of ​​the seabed soil is determined.

3. A linear wave-induced seabed shear failure assessment method based on LRBFCM type meshless method according to claim 2, characterized in that: According to the dynamic response information of the seabed, the stress information of the seabed soil is calculated, specifically: Where: σ' x , σ' y and σ' z denote the effective stress along the x, y, and z directions, respectively, and τ xz , τ yz , τ xy represent the shear stress in three directions respectively.

4. A linear wave-induced seabed shear damage assessment method based on LRBFCM type meshless method according to claim 3, characterized in that: The actual internal friction angle is calculated based on the seabed soil stress information, specifically: Where: ψ is the actual internal friction angle, σ1, σ2 and σ3 represent the three principal stresses respectively, represents the polar coordinates in the π plane, s represents the vertical distance in the π plane, and J represents the third stress invariant.

5. A linear wave-induced seabed shear failure assessment method based on LRBFCM type meshless method according to claim 4, characterized in that: According to the actual internal friction angle, the shear failure area of ​​the seabed soil is determined in combination with the Mohr-Coulomb criterion, specifically: ψ ≥ ψ f , the actual internal friction angle ψ and the critical internal friction angle ψ f When the actual internal friction angle ψ is greater than or equal to the set critical internal friction angle ψ, f Shear failure occurs.

6. An assessment system using the linear wave-induced seabed shear failure assessment method based on the LRBFCM type meshless method according to any one of claims 1 to 5, characterized in that: include, Collection module 1, used to collect wave load characteristic parameters; Collection module 2, used to collect seabed parameters; A calculation module for calculating the dynamic water pressure on the seabed surface using a linear wave analytical solution combined with wave load characteristic parameters; Modeling module, used to establish a seabed model and calculate the dynamic response information of the seabed under the action of waves in combination with seabed soil parameters; The analysis module is used to determine the shear failure area of ​​the seabed soil based on the dynamic response information of the seabed and the Moore-Coulomb criterion.

7. An electronic device, characterized in that: include: at least one processor; And, a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned linear wave-induced seabed shear damage assessment method based on the LRBFCM type gridless method as described in any one of claims 1-5.

Images