CN113761774A - Method and system for simulating landslide process of seabed - Google Patents
Method and system for simulating landslide process of seabed Download PDFInfo
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Abstract
The invention provides a method and a system for simulating a landslide process of a sea bottom, which comprises the following steps: constructing a landslide body particle model after grid-free discretization of a seabed landslide body simulation area, and initializing physical and mechanical parameter values of landslide body particles; constructing a tight branch domain of adjacent particles of the slip mass particles, traversing the slip mass particles in the tight branch domain of the adjacent particles in each time step to obtain a relative motion state among the slip mass particles and a stress tensor state of the slip mass particles, judging a critical state of the slip mass particles according to the relative motion state and selecting a corresponding constitutive equation; and obtaining a prediction-correction cycle result of the solid-liquid boundary density and the pressure according to the constitutive equation, obtaining the density change rate, the stress change rate and the momentum change rate of the landslide body particles, updating the physical and mechanical parameter values of the landslide body particles according to the prediction-correction cycle result, and realizing effective simulation of the sliding and accumulation catastrophe process of the landslide body after the submarine landslide disaster occurs within a set time step.
Description
Technical Field
The invention relates to the technical field of ocean engineering, in particular to a method and a system for simulating a landslide process of a sea bottom.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
The submarine landslide is a common geological disaster in ocean engineering, is widely distributed in regions such as offshore large land slopes, river estuaries, deep sea valleys and the like, masters the post-disaster evolution process of submarine landslide, is beneficial to the stability evaluation of submarine artificial sites and dredger island slopes, and is beneficial to the smoothness of submarine communication optical cables, petroleum engineering facilities and submarine navigation channels. The submarine landslide is difficult to observe visually due to the hidden characteristics of the submarine landslide, a slip surface is usually observed according to a geophysical exploration method after the landslide occurs, or the area and scale of the submarine landslide are presumed when sea surface waves are abnormal and even tsunami occurs, but the occurrence time and scale of disasters are difficult to judge effectively, disaster prevention and control are delayed greatly, the improvement of the disaster early warning and disaster prevention and reduction technical level of submarine landslide disasters is limited, and the safety of submarine engineering sites and underwater structures close to the sea area is threatened.
At present, common methods for analyzing the problem of the landslide on the sea bottom comprise a Discrete Element Method (DEM), a non-grid Galerkin method, a cellular automaton method, a discontinuous deformation analysis method (DDA) and the like, and the methods provide a certain research basis for inducing mechanisms, instability analysis and disaster assessment of the landslide on the sea bottom; the most typical difference between the sea-bottom landslide and the land landslide is that the sea-bottom landslide has large-scale sliding and long sliding distance, and the sliding speed, the sliding distance or the accumulation process of the sea-bottom landslide still needs to be deeply researched.
Because the cause of the submarine landslide disaster is different from the slip occurrence environment, the movement of the landslide body has different driving mechanisms. For the initial damage stage of the slope, the seabed presents obvious continuous medium properties, and soil mechanics and rock mechanics rules can be adopted for judging or explaining the stable state; but for the post-failure stage, the landslide body exhibits significant flow characteristics that often need to be addressed by relying on fluid mechanics theory. In the process of occurrence of the submarine landslide, the landslide body interacts with seawater, the proportion of water to the slope body material changes all the time, and the physical and mechanical properties and physical states of the landslide body also change; aiming at the sliding and stacking process of the seabed landslide body, a static stacking solid state stage and a fast flowing liquid sliding process exist. Although the elastic-plastic constitutive equation in the field of solid mechanics and the viscoplastic constitutive equation in the field of fluid mechanics can describe the mechanical behavior of the landslide body in the stacking state and the gliding flow state, how to correctly and timely select the elastic-plastic constitutive equation or the viscoplastic constitutive equation enables the model to accurately describe the characteristics of solid-state stacking, liquid-state sliding and solid-liquid conversion of the seabed landslide body, and the method is not completely solved so far.
In addition, although the Smooth Particle Hydrodynamic (SPH) method has been widely used in fluid problem research such as marine engineering and geological disasters, when a large-scale fluid scene is faced, the standard SPH method is greatly compressed when simulating a fluid, causing a serious distortion phenomenon, and thus, the incompressible fluid simulation analysis problem needs to be solved.
Disclosure of Invention
In order to solve the problems, the invention provides a method and a system for simulating a landslide process, which can obtain the sliding and stacking characteristics of a variable landslide body, realize effective simulation of the sliding and stacking catastrophe process of the landslide body after a landslide disaster happens, judge the critical state of a particle model in real time, track the sliding or stacking characteristics of particles, and avoid the problem of particle boundary density and pressure distortion in the solid-liquid conversion process.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for simulating a landslide process on a sea floor, comprising:
constructing a landslide body particle model after grid-free discretization of a seabed landslide body simulation area, and initializing physical and mechanical parameter values of landslide body particles;
constructing a tight branch domain of adjacent particles of the slip mass particles, traversing the slip mass particles in the tight branch domain of the adjacent particles in each time step to obtain a relative motion state among the slip mass particles and a stress tensor state of the slip mass particles, judging a critical state of the slip mass particles according to the relative motion state and selecting a corresponding constitutive equation;
and obtaining a prediction-correction cycle result of the solid-liquid boundary density and the pressure according to the constitutive equation, obtaining the density change rate, the stress change rate and the momentum change rate of the slip mass particles, updating the physical and mechanical parameter values of the slip mass particles according to the prediction-correction cycle result, and obtaining a simulation result of the sliding and accumulation process of the seabed slip mass within a set time step.
As an alternative embodiment, a non-slip boundary particle layer with speed is created outside the boundary of the landslide body particle model according to boundary repulsive particles and virtual particles, the gravity action and the wave load of the sea water are exerted on the sea water particles, and the land slope acting force and the structural acting force of the slope body are converted into stress boundary conditions to be exerted on the boundary particle layer to serve as displacement boundary conditions.
As an alternative embodiment, the process of constructing the adjacent particle tight branch domain of the slip mass particle comprises: and matching the landslide body particles by adopting a linked list search method according to the smooth kernel function and the particle neighborhood search radius to form support domains and influence domains of all the landslide body particles, determining the interaction relationship among the landslide body particles, and constructing adjacent particle tight support domains of all the landslide body particles in the seabed landslide body simulation region.
As an alternative embodiment, the process of determining the critical state of the sliding mass particle and selecting the corresponding constitutive equation includes: selecting an elastic-plastic constitutive equation when the landslide body particles are in a solid critical state, selecting a viscoplastic constitutive equation when the landslide body particles are in a liquid flow critical state, and selecting a non-Newtonian fluid rheological model when the landslide body particles are in a solid-liquid conversion state.
As an alternative embodiment, in the prediction-correction cycle process of the solid-liquid boundary density and the pressure, in each time step, the sum of the densities of the landslide body particles in the adjacent particle tight branch regions is carried out by adopting a display integration method to obtain the density change rate of the landslide body particles, and the update of the landslide body particle pressure value is carried out by adopting a PCISPH prediction-correction strategy according to the density change rate of the landslide body particles and a pressure state equation.
As an alternative embodiment, in the prediction-correction cycle process of the solid-liquid boundary density and the pressure, after the particle pressure value is updated, whether the pressure value after the prediction-correction cycle meets the cycle condition is judged, if not, the incompressible state is reached, and the prediction-correction cycle is exited; otherwise, the prediction-correction loop continues until an incompressible state is reached.
As an alternative embodiment, the calculation process of the density change rate, the stress change rate and the momentum change rate of the particles of the sliding mass comprises the following steps: and solving the SPH approximate expression of the particle model continuity equation by a nuclear approximation method and a particle approximation method to obtain the density change rate, obtaining the stress change rate according to the SPH approximate expression of the momentum equation, and obtaining the momentum change rate according to the SPH approximate expression of the energy equation.
In a second aspect, the present invention provides a landslide process simulation system, comprising:
the model building module is configured to build a landslide body particle model after grid-free discretization of a seabed landslide body simulation area and initialize physical and mechanical parameter values of landslide body particles;
the constitutive equation determining module is configured to construct a slip mass particle adjacent particle tight branch domain, traverse the slip mass particles in the adjacent particle tight branch domain in each time step, obtain a relative motion state among the slip mass particles and a stress tensor state of the slip mass particles, judge a critical state of the slip mass particles, and select a corresponding constitutive equation;
and the simulation module is configured to obtain a prediction-correction cycle result of the solid-liquid boundary density and the pressure according to the constitutive equation, obtain the density change rate, the stress change rate and the momentum change rate of the slip mass particles, update the physical and mechanical parameter values of the slip mass particles according to the density change rate, the stress change rate and the momentum change rate, and obtain a simulation result of the sliding and stacking process of the seabed slip mass within a set time step.
In a third aspect, the present invention provides an electronic device comprising a memory and a processor, and computer instructions stored on the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method of the first aspect is performed.
In a fourth aspect, the present invention provides a computer readable storage medium for storing computer instructions which, when executed by a processor, perform the method of the first aspect.
Compared with the prior art, the invention has the beneficial effects that:
the method introduces the core thought and the calculation advantages of smooth particle fluid dynamics into the field of ocean engineering, can capture the sliding and stacking characteristics of variable submarine landslide bodies, effectively describes the carrying process of the submarine landslide bodies, determines the sliding scale, the sliding speed and the stacking characteristics of the landslide bodies, realizes effective simulation of the sliding and stacking catastrophe process of the landslide bodies after submarine landslide disasters occur, and has higher calculation efficiency and precision.
The method can simulate the fluid to obtain the data result of each particle in the computational domain based on the SPH method, is easier to track the fluid surface and reconstruct the fluid surface, is convenient to analyze the mixed fluid details of the landslide body and the seawater and visualize the result, and is an effective numerical simulation method for reproducing the sliding and accumulation process of the submarine landslide body.
The method judges the critical state of the particle system in real time in the whole solving process, and tracks the sliding or stacking characteristics of the particles; meanwhile, the problems of density and pressure distortion of particle boundaries in the solid-liquid conversion process are avoided, and efficient solving of the problem domain is effectively guaranteed.
The method is used for modeling aiming at the whole solving area, can reproduce the sliding behavior and the accumulation characteristic of the landslide body, simultaneously captures the surge effect in the landslide process, can accurately track the sliding speed, the sliding scale and the accumulation distribution condition of the landslide body, and can provide theoretical guidance for the safety protection of offshore engineering.
In order to better adapt to the characteristics of large-scale slip mass sliding in the process of submarine landslide and realize high-efficiency Incompressible fluid simulation, the invention adopts a PCISPH (predictive-Corrective integral SPH) method based on a prediction-correction strategy to simulate the slip and accumulation process of the submarine slip mass, and improves the simulation efficiency by setting a larger time step length and simultaneously enhances the incompressibility of the fluid.
Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
Fig. 1 is a flowchart of a method for simulating a landslide process of a sea floor according to embodiment 1 of the present invention.
Detailed Description
The invention is further described with reference to the following figures and examples.
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should be understood that the terms "comprises" and "comprising", and any variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
Example 1
The method is only used for simulating the stage process of landslide mass accumulation after the occurrence of the submarine landslide disaster, and aims to obtain the sliding and accumulation characteristics of the landslide mass in the motion process, so that the occurrence scale, the sliding speed and the accumulation characteristics of the landslide mass are determined, and finally, a basis is provided for landslide early warning prediction, landslide risk evaluation and the like. In addition, due to the complex type of seabed stratum, even after the disaster of the seabed landslide occurs, the landslide body can be gradually changed into a liquid landslide body which slides quickly along with the interaction with seawater in the gliding process along with the solid-state sliding process of integral sliding.
Based on this, as shown in fig. 1, the present embodiment provides a method for simulating a sliding and stacking process of a landslide body in a landslide process, which specifically includes the following steps:
s1: and constructing a landslide body particle model after grid-free discretization of the seabed landslide body simulation area, and initializing physical and mechanical parameter values of the landslide body particles.
Specifically, in the embodiment, a seabed landslide body simulation calculation area is subjected to non-grid discretization to form a certain number of SPH particles with different physical state attributes, a non-grid landslide body particle model of the whole slope is constructed, and initial physical and mechanical parameters are assigned to the particles;
preferably, the physical-mechanical parameters include: density, mass, stress, position, velocity, period, amplitude, etc.
In the embodiment, a non-slip boundary particle layer is established outside the boundary according to the boundary repulsive particles and the virtual particles, so that the influence of the boundary effect on the core calculation area is compensated; meanwhile, double-layer boundary layer particles are laid in a staggered mode, repelling particles are increased to prevent particles caused by excessive speed of real particles from escaping, a certain speed is given to virtual particles, and the effect that the speed on the boundary is not slipped is achieved.
In the embodiment, by combining the reverse repulsive force of the repulsive particles and the initial velocity value of the virtual particles, the boundary slippage of the particles between the non-physical penetration boundary and the virtual particles can be prevented, the precision of the SPH approximation method at the boundary region is improved, the accuracy of the result of the boundary simulation of the calculation region is ensured, and the boundary layer particles are not in the actual calculation region and are only used for compensating and correcting the solution of the real particles on the boundary of the calculation region.
In the embodiment, the gravity action and the wave action of the seawater are applied to seawater particles, the land slope acting force and the structural acting force applied to a slope body are converted into the stress boundary condition of a slope body particle calculation area, and the stress boundary condition is applied to boundary layer particles to apply displacement boundary condition;
meanwhile, the PCISPH method is adopted to carry out self-adaptive sampling on boundary particles, and the incompressible type in the fluid (seawater and liquid landslide mass) and the impermeability of the solid boundary (non-slip landslide mass) are simultaneously ensured in an iterative solution mode through prediction-correction circulation.
In particular, a seabed side slope is usually in an infinite seawater coverage environment, seawater particles and slope particles interact in the gliding process of a landslide body, and because the particle sampling at a liquid boundary depends on a solid boundary, and the boundary particles on the surface of the slope body are complex in distribution, the calculation error of the fluid particle density is often caused at a fluid-solid interface. To better address the difficulty of ensuring impermeability of fluid particles to solid boundaries at large time steps or large velocity differentials, the present embodiment applies boundary forces once inside and once outside of the predictor-corrector loop, i.e., first applying the boundary forces once in the external force calculation step, and then updating the boundary forces based on the predicted fluid positions for the next iteration of the calculation when the pressure is calculated at the last step of the predictor-corrector loop.
Preferably, the incompressibility condition is satisfied by continuously correcting the density of the fluid particles to approach the static density during the iteration process, whereby the prediction-correction loop of the PCISPH method can be solved iteratively while ensuring incompressibility inside the fluid and impermeability to solid boundaries.
Preferably, in the prediction-correction cycle, the velocity and position of the particle are predicted from the resultant force experienced by the particle, and the density of the fluid particle is determined from the predicted position of the fluid particle
And density error prediction
Updating the particle pressure value by a pressure updating formula; calculating the pressure F at the end of the cyclep(t) judging whether a circulation condition is satisfied; if not, indicating that the fluid reaches the incompressible state, and exiting the cycle; otherwise, the cycle continues until the fluid reaches an incompressible state.
Preferably, the pressure update formula for PCISPH is as follows:
wherein p isiThe value of the pressure intensity is set,
to predict the error of the fluid particle density from the static density, δ is the calculated coefficient for the case where the fluid particle is filled with neighboring particles.
S2: and constructing a tight branch domain of adjacent particles of the slip mass particles, traversing the slip mass particles in the tight branch domain of the adjacent particles in each time step to obtain a relative motion state among the slip mass particles and a stress tensor state of the slip mass particles, judging the critical state of the slip mass particles according to the relative motion state and selecting a corresponding constitutive equation.
In the embodiment, a proper smooth kernel function and a particle neighborhood search radius are selected, a linked list search method is adopted to perform particle pairing, support domains and influence domains of all SPH particles are formed, the interaction relationship among the particles is determined, and the adjacent particle tight support domains of all the particles in the simulation calculation region are constructed.
Preferably, an integral representation function method is adopted to integrate an arbitrary function and a smooth kernel function, the smooth function W (x-x ', h) is adopted to replace the kernel function delta (x-x ') of the delta function, and W (x-x ', h) is defined in a tight branch domain; in the smooth function, the SPH smooth kernel selects a cubic spline kernel, that is:
wherein q is | r |/h, | r | is the distance between two particles, h is the smooth kernel length associated with the particle, and to maintain normalization (standardization), the distribution of the setting constants in one, two and three dimensions takes the values: ch＝1/h、Ch＝15/(7πh2)、Ch＝3/(2πh3)。
In this embodiment, in each time step, traversal search is performed on the landslide body particles in the adjacent particle tight branch region, the relative motion state between the landslide body particles and the stress tensor state of the landslide body particles are obtained, and the critical state of the particles is judged, so that an elastic-plastic constitutive equation, a viscoplastic constitutive equation or a solid-liquid transformation constitutive equation is selected, and the time step solution of the constitutive model is further completed.
Specifically, the submarine landslide process is accompanied by obvious stage characteristics, has mechanical behaviors of solid-state, liquid-state and solid-liquid transformation, and the key point for describing the transformation process or moment is to accurately obtain the stress critical state in the sliding process of the landslide body and provide a critical state partial stress expression of solid-liquid transformation.
Many researches show that the traditional description of the critical state of the soil body has general significance on the particle medium material and has important significance on building a particle medium constitutive model; but the critical state of the soil body in the traditional soil mechanics
And soil body critical state described by rate type relational expression
The bias stress tensor S under the critical state can not be completely determined; meanwhile, different constitutive models have different descriptions of the bias stress tensor S under the critical state, namely in the soil mechanics structure (in the field of solid mechanics), S*0; in the visco-plastic structure (in the field of hydrodynamics), S is in a limit state,
the above bias stress states are not uniform.
In this embodiment, the critical state of the particle system is determined by analyzing the stress, the stress ratio, and the deformation power per unit volume in the critical state of the particle system with respect to the critical state of the particle having different phase attributes of the particle system, obtaining the maximum value of the deformation power per unit volume of the particle system, and defining the critical bias stress tensor of the solid-liquid transition.
Selecting a constitutive equation of a particle system in a corresponding state according to the judgment of the critical state in the particle tight branch region, wherein the constitutive equation comprises the following steps: selecting an elastoplasticity constitutive equation when the sliding mass presents a solid sliding characteristic, selecting a viscoplasticity constitutive equation when the sliding mass presents a liquid flowing characteristic, and selecting a non-Newtonian fluid constitutive equation of the sliding mass material in the solid-liquid conversion process according to the non-Newtonian fluid characteristic and the change of the liquid sliding mass in the sliding process; during the gliding process of the landslide body material, seawater interacts with the landslide body, when the solid particle volume of the landslide body exceeds a certain value, the landslide body slides to present the mud flow characteristic of non-Newtonian fluid, and through laboratory measurement and reference of relevant empirical data, a rheological constitutive equation of the landslide body material for representing liquid-like flow, such as a modified Bingham or modified Herschel-Bulkley equation, can be established.
S3: and obtaining a prediction-correction cycle result of the solid-liquid boundary density and the pressure intensity, and the density change rate, the stress change rate and the momentum change rate of the slip mass particles according to the constitutive equation, updating physical and mechanical parameter values of the slip mass particles according to the prediction-correction cycle result, and obtaining a simulation result of the sliding and accumulation process of the seabed slip mass within a set time step.
In the embodiment, in each time step, a display integration method is adopted to solve a continuity equation, a momentum equation and an energy equation of the particles in the tight branch region and predict and correct the density pressure of the particles at the solid-liquid boundary, and the density summation, stress and partial stress of the particles in the region, energy change rate and other physical quantity calculations are carried out;
specifically, a display integration method is adopted to carry out particle density summation in a tight branch region, adjacent particles of the particles are searched, particle density information at the moment is solved, and updating pressure is corrected through predicting density fluctuation in prediction-correction of solid-liquid boundary particle density pressure; solving stress, partial stress tensor and momentum change rate of the particles in the tight branch domain based on a continuity equation, a momentum equation and an energy equation;
furthermore, an SPH approximate expression of a continuity equation of the particle model is solved through a nuclear approximation method and a particle approximation method, and the change rate of the particle density in the particle tight branch domain is obtained; updating pressure correction is carried out by adopting a prediction-correction strategy according to the predicted density fluctuation and a pressure state equation, and the prediction-correction of the SPH particle boundary is completed; and solving the stress change of the particle system according to the SPH approximate expression of the momentum equation, and obtaining the momentum change rate of the particle system according to the SPH approximate expression of the energy equation.
In this embodiment, according to the above solution result, the physical and mechanical information of the particles of the landslide body is updated, which mainly includes the coordinates, stress, partial stress, acceleration, momentum change rate, etc. of the particles; and then entering the next calculation time step cycle, setting time step intervals, outputting physical and mechanical information of the particle system after solving the time step at each interval, outputting results by a post-processing program for batch processing, and finally completing the simulation of the sliding and stacking process of the seabed landslide body.
Example 2
The present embodiment provides a submarine landslide process simulation system, including:
the model building module is configured to build a landslide body particle model after grid-free discretization of a seabed landslide body simulation area and initialize physical and mechanical parameter values of landslide body particles;
the constitutive equation determining module is configured to construct a slip mass particle adjacent particle tight branch domain, traverse the slip mass particles in the adjacent particle tight branch domain in each time step, obtain a relative motion state among the slip mass particles and a stress tensor state of the slip mass particles, judge a critical state of the slip mass particles, and select a corresponding constitutive equation;
and the simulation module is configured to obtain a prediction-correction cycle result of the solid-liquid boundary density and the pressure according to the constitutive equation, obtain the density change rate, the stress change rate and the momentum change rate of the slip mass particles, update the physical and mechanical parameter values of the slip mass particles according to the density change rate, the stress change rate and the momentum change rate, and obtain a simulation result of the sliding and stacking process of the seabed slip mass within a set time step.
It should be noted that the modules correspond to the steps described in embodiment 1, and the modules are the same as the corresponding steps in the implementation examples and application scenarios, but are not limited to the disclosure in embodiment 1. It should be noted that the modules described above as part of a system may be implemented in a computer system such as a set of computer-executable instructions.
In further embodiments, there is also provided:
an electronic device comprising a memory and a processor and computer instructions stored on the memory and executed on the processor, the computer instructions when executed by the processor performing the method of embodiment 1. For brevity, no further description is provided herein.
It should be understood that in this embodiment, the processor may be a central processing unit CPU, and the processor may also be other general purpose processors, digital signal processors DSP, application specific integrated circuits ASIC, off-the-shelf programmable gate arrays FPGA or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and so on. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory may include both read-only memory and random access memory, and may provide instructions and data to the processor, and a portion of the memory may also include non-volatile random access memory. For example, the memory may also store device type information.
A computer readable storage medium storing computer instructions which, when executed by a processor, perform the method described in embodiment 1.
The method in embodiment 1 may be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor. The software modules may be located in ram, flash, rom, prom, or eprom, registers, among other storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor. To avoid repetition, it is not described in detail here.
Those of ordinary skill in the art will appreciate that the various illustrative elements, i.e., algorithm steps, described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (10)
1. A method for simulating a landslide process on a sea floor, comprising:
constructing a landslide body particle model after grid-free discretization of a seabed landslide body simulation area, and initializing physical and mechanical parameter values of landslide body particles;
constructing a tight branch domain of adjacent particles of the slip mass particles, traversing the slip mass particles in the tight branch domain of the adjacent particles in each time step to obtain a relative motion state among the slip mass particles and a stress tensor state of the slip mass particles, judging a critical state of the slip mass particles according to the relative motion state and selecting a corresponding constitutive equation;
and obtaining a prediction-correction cycle result of the solid-liquid boundary density and the pressure according to the constitutive equation, obtaining the density change rate, the stress change rate and the momentum change rate of the slip mass particles, updating the physical and mechanical parameter values of the slip mass particles according to the prediction-correction cycle result, and obtaining a simulation result of the sliding and accumulation process of the seabed slip mass within a set time step.
2. The method for simulating a submarine landslide process according to claim 1, wherein a non-slip boundary particle layer is created outside the boundary of the landslide body particle model according to the velocity of boundary repulsive particles and virtual particles, the gravity action and wave load of the sea water are applied to the sea water particles, and the land slope force and the construction force of the slope body are converted into stress boundary conditions and applied to the boundary particle layer as displacement boundary conditions.
3. The method for simulating a landslide process of claim 1, wherein the process of constructing the immediate vicinity of the landslide body particle comprises: and matching the landslide body particles by adopting a linked list search method according to the smooth kernel function and the particle neighborhood search radius to form support domains and influence domains of all the landslide body particles, determining the interaction relationship among the landslide body particles, and constructing adjacent particle tight support domains of all the landslide body particles in the seabed landslide body simulation region.
4. The method of claim 1, wherein the step of determining the critical state of the landslide body particles and selecting the corresponding constitutive equation comprises: selecting an elastic-plastic constitutive equation when the landslide body particles are in a solid critical state, selecting a viscoplastic constitutive equation when the landslide body particles are in a liquid flow critical state, and selecting a non-Newtonian fluid rheological model when the landslide body particles are in a solid-liquid conversion state.
5. The method for simulating a landslide process of claim 1, wherein during the prediction-correction cycle of solid-liquid boundary density and pressure, the landslide body particle density within the adjacent particle tight-branching region is summed by display integration to obtain a landslide body particle density change rate at each time step, and the landslide body particle pressure value is updated by using a PCISPH prediction-correction strategy according to the landslide body particle density change rate and a pressure state equation.
6. The method for simulating a submarine landslide process according to claim 1, wherein in the prediction-correction cycle process of solid-liquid boundary density and pressure, after updating the particle pressure value, it is determined whether the pressure value after the prediction-correction cycle satisfies the cycle condition, and if not, it indicates that the incompressible state has been reached, and the prediction-correction cycle is exited; otherwise, the prediction-correction loop continues until an incompressible state is reached.
7. The method for simulating a landslide process on the sea floor of claim 1, wherein the calculating of the density change rate, the stress change rate, and the momentum change rate of the landslide body particles comprises: and solving the SPH approximate expression of the particle model continuity equation by a nuclear approximation method and a particle approximation method to obtain the density change rate, obtaining the stress change rate according to the SPH approximate expression of the momentum equation, and obtaining the momentum change rate according to the SPH approximate expression of the energy equation.
8. A seafloor landslide process simulation system, comprising:
the model building module is configured to build a landslide body particle model after grid-free discretization of a seabed landslide body simulation area and initialize physical and mechanical parameter values of landslide body particles;
the constitutive equation determining module is configured to construct a slip mass particle adjacent particle tight branch domain, traverse the slip mass particles in the adjacent particle tight branch domain in each time step, obtain a relative motion state among the slip mass particles and a stress tensor state of the slip mass particles, judge a critical state of the slip mass particles, and select a corresponding constitutive equation;
and the simulation module is configured to obtain a prediction-correction cycle result of the solid-liquid boundary density and the pressure according to the constitutive equation, obtain the density change rate, the stress change rate and the momentum change rate of the slip mass particles, update the physical and mechanical parameter values of the slip mass particles according to the density change rate, the stress change rate and the momentum change rate, and obtain a simulation result of the sliding and stacking process of the seabed slip mass within a set time step.
9. An electronic device comprising a memory and a processor and computer instructions stored on the memory and executed on the processor, the computer instructions when executed by the processor performing the method of any of claims 1-7.
10. A computer-readable storage medium storing computer instructions which, when executed by a processor, perform the method of any one of claims 1 to 7.
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