Discrete element simulation method for compression-torsion superposition recoil structure deformation

Abstract

The invention provides a discrete element simulation method for compression-torsion superposition recoil structure deformation, and the method comprises the steps: 1, constructing an appropriate model boundary condition, and dividing the appropriate model boundary condition into several types of modules with different motion conditions; 2, on the basis of the actual sedimentary stratum characteristics of the target research area, simulated stratum mesoscopic contact parameters are determined; step 3, designing a first-stage pre-stored back-flushing tectonic motion; step 4, designing a second-stage compression-torsion structural movement on the basis of the first-stage counter-impact structural movement; and 5, performing structural analysis based on a model result under the two-stage structural movement. According to the discrete element simulation method for the compression-torsion superposition recoil tectonic deformation, the tectonic evolution process of a research area is speculated through quantitative analysis of a simulation result, parameters involved in model construction are few and easy to implement, simulation software can provide various contact parameters, and a fault interpretation scheme is more reliable and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of structural simulation, and particularly to a discrete element simulation method for compressive-torsional superimposed thrust structural deformation. Background Art

[0002] The generalized strike-slip structure refers to the structural deformation pattern generated under the action of shear stress in the lithosphere or crust, generally including a main fault and a series of secondary faults intersecting the main fault at a small angle. Based on field outcrops and topographic maps, it can be identified according to the development of en echelon joints, steep main faults, abnormal erosion phenomena on both sides of the faults, volcanic activities, as well as long linear structures and abnormal topographic changes on the topographic maps. With the development of geophysical technologies, researchers have found that steeply dipping vertical faults extending far on seismic profiles, "flower-shaped" structures where branch faults separate upward, large differences in sedimentary thickness on both sides of the faults, and the appearance of linear isolated main faults, en echelon faults, and curved contraction or extension structures in the plan view all reflect the development of deep strike-slip faults.

[0003] Most of the existing geological structure phenomena are formed by the superposition of multiple stages of tectonic movements with different natures. In a shear stress environment, the fault planes generated in the early tectonic movements, as weak structural areas, will deform first. When predecessors conducted tectonic physical simulation experiments on strike-slip faults, they often adopted the method of presetting a basement fault to make the sedimentary strata on both sides move relatively. However, for the cases where the pre-existing faults are normal faults or reverse faults, there is still a lack of simulation experiments and other means to support quantitative research and structural analysis.

[0004] In the Chinese patent application with the application number: CN201611023470.5, it involves a method for calculating the strike-slip amount through tectonic physical simulation experiments, including the following steps: S1: Preliminary preparation for the tectonic physical simulation experiment; S2: Conducting a tectonic physical simulation experiment on the end-tail fan-shaped structure; S3: Using statistical methods to obtain the functional relationship between the experimental distance of the fan-shaped fault of the fan-shaped structure projected on the main fault and the experimental strike-slip amount in the tectonic physical simulation experiment; S4: Generalizing the functional relationship to the actual strike-slip fault according to the similarity principle; S5: Calculating the actual strike-slip amount. The invention is based on the similarity principle of tectonic physical simulation experiments, combines statistical principles and image processing technologies, realizes the accurate calculation of the strike-slip displacement amount of strike-slip faults, has a simple calculation method, high calculation accuracy, convenient operation, wide application range, and provides convenience for geological research.

[0005] In the Chinese patent application with the application number: CN201810287211.6, a method for analyzing the structural evolution of strike-slip faults is involved. By calculating the paleo-relief of the strike-slip fault at different positions, the periodic rhythmic changes of the paleo-relief of the strike-slip fault along the strike direction are analyzed; using the restored horst-graben structures on both sides of the strike-slip fault at different times, the basin prototype before the deposition of different strata on both sides of the strike-slip fault is determined, and the "damping section" of the strike-slip fault is identified; by calculating the unit activity intensity of the fault, the strike-slip amount of the strike-slip fault is characterized; using the calculated strain energy release rate of the strike-slip fault, the dynamic mechanisms of different parts of the strike-slip fault are analyzed; using numerical simulation of the tectonic stress field to explain the fault from the dynamic aspect and verify the genetic mechanism of the strike-slip fault. The invention systematically proposes a method for analyzing the genetic mechanism and evolution process of strike-slip faults from three aspects of geometry, kinematics, and dynamics, from a four-dimensional perspective of time and space.

[0006] In the Chinese patent application with the application number: CN201910228977.1, a method for identifying the maximum paleo-stress direction during the development period of strike-slip faults is involved, including the following steps: conducting a fine interpretation of the strike-slip fault, dividing the strike-slip fault into superimposed uplift segments, superimposed tensile segments, and translational segments, selecting typical overlapping segments, and identifying the local principal stress directions to establish a geological and mechanical model for numerical simulation of the stress field of the typical overlapping segments; within the range of the regional stress field direction of the strike-slip fault, loading different directions of the regional stress field on the model; determining the direction of the maximum paleo-stress during the development period of the strike-slip fault. The advantage of using this invention is that by establishing the relationship between the strike directions of secondary faults inside the overlapping segments of the strike-slip fault and the corresponding regional stress field directions, the maximum paleo-stress direction during the development period of the strike-slip fault is identified, which has important guiding significance for understanding the regional tectonic background, analyzing the origin and evolution of strike-slip faults, and exploring the development laws of the derivative fault-fracture systems in different parts of strike-slip faults and their roles in controlling reservoirs and hydrocarbon accumulations.

[0007] The above existing technologies are quite different from the present invention and fail to solve the technical problems we want to solve. Therefore, we have invented a new discrete element simulation method for compressional-shear superimposed thrust tectonic deformation. Summary of the Invention

[0008] The object of the present invention is to provide a discrete element simulation method for compressional-shear superimposed thrust tectonic deformation that speculates on the tectonic evolution process of the study area through quantitative analysis of simulation results.

[0009] The object of the present invention can be achieved by the following technical measures: a discrete element simulation method for compressional-shear superimposed thrust tectonic deformation, and this discrete element simulation method for compressional-shear superimposed thrust tectonic deformation includes:

[0010] Step 1, construct appropriate model boundary conditions and divide them into several modules with different motion conditions;

[0011] Step 2: Determine the mesoscopic contact parameters of the simulated formation based on the actual sedimentary formation characteristics of the target research area;

[0012] Step 3: Design the first-stage pre-existing thrust tectonic movement;

[0013] Step 4: Design the second-stage compressional-shear tectonic movement based on the first-stage thrust tectonic movement;

[0014] Step 5: Conduct tectonic analysis based on the model results under the two-stage tectonic movements.

[0015] The object of the present invention can also be achieved by the following technical measures:

[0016] In Step 1, construct a motion module capable of simultaneously carrying out motions in three-dimensional space, including a pre-existing thrust fault plane with a preset angle of the basement, partial side baffles on the hanging wall of the fault, partial side baffles on the footwall of the fault, partial bottom plates on the hanging wall of the fault, and partial bottom plates on the footwall of the fault.

[0017] In Step 1, considering the gap between the hanging wall and the footwall caused by the strike-slip amount of the designed model, an inclined baffle needs to be set between the two motion modules to ensure that the particles do not leak during the second-stage motion of the model.

[0018] In Step 1, determine the three-dimensional geometric parameters of the model according to the range of deformation expected to occur in the simulated formation, specifically referring to the inclination angle of the preset fault plane, the length of the preset fault plane, the lengths of the hanging wall and footwall parts, the width and height, and the corresponding lengths and widths of the bottom plate parts of the hanging wall and footwall.

[0019] In Step 2, in the discrete element numerical simulation, change the macroscopic deformation performance of the model according to the characteristics of the particles and the wall itself and the setting of the mesoscopic parameters of the contact model therebetween.

[0020] In Step 2, in combination with the sedimentary formation properties of the actual research area, give the mesoscopic parameters of the particles in the discrete element numerical model through the empirical formula between the macroscopic parameters and the mesoscopic parameters.

[0021] In Step 2, divide the simulated formation as needed, and display the simulated formation in groups by different colors, including the vertical grouping of homogeneous formations. In addition, the simulated formations with different characteristics can also be differentially displayed.

[0022] In Step 3, determine the model baffles that move in the first stage. The thrust movement is formed by the upward movement of the hanging wall module along the preset fault plane, while the footwall module is controlled to remain fixed.

[0023] In Step 3, the baffles that need to be given a motion speed include three parts: the preset fault plane, the hanging wall side baffle, and the hanging wall bottom plate.

[0024] In step 3, due to the existence of the preset fault, the true displacement occurs parallel to the preset fault plane. When setting the velocity, it needs to be decomposed into two directions: the horizontal direction perpendicular to the strike and the vertical direction, and attention should be paid to the matching relationship of its values in trigonometric functions.

[0025] In step 4, the compressional-shear movement is the simultaneous occurrence of strike-slip movement and thrust movement. Therefore, the setting of the thrust movement is the same as that in the previous stage, and the moving baffles involved include three parts: the preset fault plane, the upper plate side baffle, and the upper plate bottom plate; the strike-slip movement is the relative movement of the upper and lower plate modules, and the velocity setting of this part involves the side baffles and bottom plates of both the upper and lower plates at the same time.

[0026] In step 4, considering the gap generated by the relative displacement caused by the strike-slip movement between the upper and lower plate modules, the growth of the diagonal baffle between the upper and lower plate modules including their side baffles and bottom plates is also involved to compensate for the generated gap and ensure that no particles leak.

[0027] In step 4, when setting the velocity of the second-stage compressional-shear movement, the movement decomposition in three spatial directions is involved; the upper plate module includes the thrust velocity components in the horizontal direction perpendicular to the strike and the vertical direction, and the strike-slip velocity component in the horizontal direction parallel to the strike of the preset fault plane is increased; on the other hand, the lower plate module is set with a strike-slip velocity component opposite to the strike-slip direction of the upper plate module.

[0028] In step 5, during the numerical simulation experiment, the results of multiple steps of the model are saved, including the results after the completion of the thrust movement and the model results are saved at certain intervals during the compressional-shear movement. Based on the contact properties or grouping results of the saved model results, structural analysis is carried out according to the continuous deformation results.

[0029] In step 5, horizontal deformation characteristics and slice analysis along the strike-slip direction are carried out on the saved model results. Due to the limitation of the calculation speed, the number of particles is not enough to fully approach the actual sedimentary formation situation. Therefore, for the structural phenomena with obvious internal fractures in the results, it is necessary to identify and observe them by means of contact forces.

[0030] In step 5, structural interpretation is carried out on the simulated deformation results, including the combined characteristics of faults on plane and profile slices; and quantitative statistical analysis is carried out on it, and the actual stress action mechanism during the deformation process is restored according to its geometric performance; furthermore, a reasonable structural evolution process is proposed for the study area and theoretical support is provided for it.

[0031] The object of the present invention can also be achieved by the following technical measures: a discrete element simulation system for compressional-shear superimposed thrust structural deformation, and this discrete element simulation system for compressional-shear superimposed thrust structural deformation uses the discrete element simulation method of compressional-shear superimposed thrust structural deformation to quantitatively analyze and infer the structural evolution process of the study area.

[0032] The discrete element simulation method for the compression-torsion superposed thrust tectonic deformation in the present invention solves the technical problems that the genetic process of the strike-slip fault system developed on the pre-existing thrust fault plane in the compression-torsion shear environment cannot be verified and there is a lack of effective correlation between the theory and the actual genesis. The beneficial effects of the present invention are mainly as follows:

[0033] (1) The discrete element numerical simulation method and device for the compression-torsion superposed thrust tectonic deformation provided by the present invention, based on the understanding of the actual geological conditions of the research area, set the speed of the model baffle to deform the simulated formation filled inside, and obtain the simulation results. The tectonic evolution process of the research area is speculated through the quantitative analysis of the simulation results.

[0034] (2) The parameters involved in the construction of this model are few, easy to implement, and the simulation software can provide various types of contact parameters, and the fault interpretation scheme is more reliable and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a three-dimensional schematic diagram of the movement setting of the first-stage thrust movement model in a compression-torsion superposed thrust discrete element simulation method according to an embodiment of the present invention;

[0036] Figure 2 It is a three-dimensional schematic diagram of the movement setting of the second-stage compression-torsion movement model in a compression-torsion superposed thrust discrete element simulation method according to an embodiment of the present invention;

[0037] Figure 3 It is a top view of the change in contact force in the strike-slip direction of a model with a strike-slip amount to thrust amount ratio of 6:1 in the second-stage compression-torsion according to an embodiment of the present invention;

[0038] Figure 4 It is a comparison diagram of the model slice perpendicular to the strike-slip direction and the seismic profile of the actual research area of a model with a strike-slip amount to thrust amount ratio of 6:1 in the second-stage compression-torsion according to an embodiment of the present invention;

[0039] Figure 5 It is a planar comparison diagram of the model result with a strike-slip amount to thrust amount ratio of 6:1 in the second-stage compression-torsion according to an embodiment of the present invention and the actual research area;

[0040] Figure 6 It is a schematic diagram of the stress analysis of the model result with a strike-slip amount to thrust amount ratio of 6:1 in the second-stage compression-torsion according to an embodiment of the present invention;

[0041] Figure 7 It is a flowchart of a specific embodiment of the discrete element simulation method for the compression-torsion superposed thrust tectonic deformation of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, and / or combinations thereof.

[0044] The discrete element simulation method for the compression-torsion superposed thrust structural deformation of the present invention includes: Step S1, based on the research purpose, construct appropriate model boundary conditions and divide them into several groups of baffles with different motion conditions; Step S2, based on the actual sedimentary formation characteristics of the target research area, determine the mesoscopic contact parameters of the simulated formation; Step S3, based on the research purpose, design the first-stage pre-existing thrust structural movement. By setting the model boundary velocity, make it undergo thrust movement; Step S4, on the basis of the simulation results of the first-stage thrust structural movement, design the second-stage compression-torsion structural movement, and the movement setting of the model boundary in this step is different from the thrust in the previous step; Step S5, finally, conduct structural analysis based on the model results under the two-stage structural movements.

[0045] During the construction process of the discrete element numerical simulation of the compression-torsion superposed thrust of the present invention, the number of involved parameters is small, it is easy to implement, and it helps to explain the compression-torsion structure and restore the structural evolution process of the research area.

[0046] The following are several specific embodiments applying the present invention

[0047] Embodiment 1

[0048] In a specific Embodiment 1 applying the present invention, as Figure 7 shown, Figure 7 is the flow chart of the discrete element simulation method for the compression-torsion superposed thrust structural deformation of the present invention. The discrete element simulation method for the compression-torsion superposed thrust structural deformation includes the following steps:

[0049] Step S101, based on the research purpose, construct appropriate model boundary conditions and divide them into several types of modules with different motion conditions; specifically including:

[0050] Construct a motion module that can simultaneously carry out motions in three-dimensional space. Specifically, in this invention, it includes a pre-existing thrust fault plane with a preset angle of the basement, partial side baffles on the hanging wall of the fault, partial side baffles on the footwall of the fault, partial bottom plates on the hanging wall of the fault, and partial bottom plates on the footwall of the fault.

[0051] In this model, considering the gap between the hanging wall and the footwall caused by the strike-slip amount of the design model, it is necessary to set an inclined baffle between the two motion modules to ensure that particles do not leak during the second-stage motion of the model.

[0052] Determine the three-dimensional geometric parameters of the model according to the predicted range of deformation of the simulated formation, specifically referring to the inclination angle of the preset fault plane, the length of the preset fault plane, the lengths of the hanging wall and footwall parts, the width and height, and the corresponding lengths and widths of the bottom plates of the hanging wall and footwall.

[0053] Step S102: Determine the mesoscopic contact parameters of the simulated formation based on the actual sedimentary formation characteristics of the target research area;

[0054] In the discrete element numerical simulation, the macroscopic deformation performance of the model is changed according to the characteristics of the particles and the wall itself and the setting of the mesoscopic parameters of the contact model between them.

[0055] Specifically, it is necessary to combine the sedimentary formation properties of the actual research area and give the mesoscopic parameters of the particles in the discrete element numerical model through the empirical formula between the macroscopic parameters and the mesoscopic parameters.

[0056] According to the needs of the invention, the simulated formation can be divided, and the simulated formation can be grouped and displayed by different colors. This includes the vertical grouping of homogeneous formations. In addition, the simulated formations with different characteristics can also be differentially displayed.

[0057] Step S103: Design the first-stage pre-existing thrust tectonic movement based on the research purpose. By setting the boundary velocity of the model, make it undergo thrust movement to generate a pre-existing thrust fault, specifically referring to:

[0058] Determine the baffle of the model that moves in the first stage. In the present invention, the thrust movement is formed by the upward movement of the hanging wall module along the preset fault plane, while the footwall module is controlled to remain fixed.

[0059] Specifically, the baffles that need to be given a movement speed include three parts: the preset fault plane, the hanging wall side baffle, and the hanging wall bottom plate.

[0060] It should also be noted that due to the existence of the preset fault, the true displacement occurs parallel to the preset fault plane. When setting the speed, it is necessary to decompose it in the horizontal direction perpendicular to the strike and the vertical direction, and pay attention to the matching relationship of its values in trigonometric functions.

[0061] Step S104: Design the second-stage compressional-shear tectonic movement based on the first-stage thrust tectonic movement. The movement setting of the model boundary in this step is different from the thrust in the previous step; specifically manifested in:

[0062] Specifically, the compressional-shear movement is a stage of movement where strike-slip movement and thrust movement occur simultaneously. Therefore, the thrust movement settings are the same as those in the previous stage, and the movement baffles involved include three parts: a preset fault plane, an upper plate side baffle, and an upper plate bottom plate. The strike-slip movement is the relative movement of the upper and lower plate modules, and the speed settings for this part involve the side baffles and bottom plates of both the upper and lower plates.

[0063] In addition, the gap generated by the relative displacement caused by the strike-slip movement between the upper and lower plate modules should also be taken into account. Therefore, it also involves the growth of diagonal baffles between the upper and lower plate modules (including their side baffles and bottom plates) to compensate for the generated gap and ensure that no particles leak.

[0064] Specifically, when setting the speed of the second-stage compressional-shear movement, it involves the decomposition of movement in three spatial directions. The upper plate module includes a thrust velocity component composed of a horizontal direction perpendicular to the strike and a vertical direction, and a strike-slip velocity component in the horizontal direction parallel to the strike of the preset fault plane is added. On the other hand, the lower plate module is set with a strike-slip velocity component opposite to the strike-slip direction of the upper plate module.

[0065] Step S105: Finally, perform structural analysis based on the model results under two-stage tectonic movements. During the numerical simulation experiment, the model results of multiple steps are saved, specifically including the results after the thrust movement is completed and the model results are saved at certain time intervals during the compressional-shear movement. The contact properties or grouped results of the saved model results can be displayed in the numerical simulation software, and structural analysis is performed based on the continuous deformation results.

[0066] Perform horizontal deformation characteristics and slice analysis along the strike-slip direction on the saved model results. Limited by the calculation speed, the number of particles is not enough to fully approximate the actual sedimentary formation situation. Therefore, for structural phenomena such as internal fractures in the results that are not obvious, it is necessary to identify and observe them by means of properties such as contact forces.

[0067] Perform structural interpretation on the simulated deformation results, including the combined characteristics of faults on plane and profile slices. And perform quantitative statistical analysis on it, and restore the actual stress action mechanism during the deformation process based on its geometric manifestations. Furthermore, propose a reasonable structural evolution process for the study area and provide theoretical support for it.

[0068] According to a discrete element numerical simulation method for compressional-shear superimposed thrust tectonic deformation provided by the present invention, a model sufficient to realize complex compressional-shear and thrust tectonic movements is constructed based on the research purpose.

[0069] Embodiment 2

[0070] In a specific Embodiment 2 of applying the present invention, the discrete element simulation method for compressional-shear superimposed thrust tectonic deformation includes the following steps:

[0071] Step S1: Based on the research purpose, construct appropriate model boundary conditions and divide them into several modules with different motion conditions.

[0072] Step S2: Based on the actual sedimentary formation characteristics of the target research area, determine the mesoscopic contact parameters of the simulated formation.

[0073] Step S3: Based on the research purpose, design the first-stage pre-existing thrust tectonic movement. By setting the model boundary velocity, make it undergo thrust movement to generate a pre-existing thrust fault.

[0074] Step S4: On the basis of the first-stage thrust tectonic movement, design the second-stage compressional-shear tectonic movement. The motion setting of the model boundary in this step is different from the thrust in the previous step.

[0075] Step S5: Finally, conduct tectonic analysis based on the model results under the two-stage tectonic movements.

[0076] Under the background of shear stress, strike-slip fault systems often develop in sedimentary formations, characterized by linear extension in the plane and narrow fault fracture zones in the section. Therefore, according to the research purpose of the present invention for compressional-shear tectonic deformation, a longer dimension should be set in the direction of strike-slip displacement, and a reasonable width should be set in the thrust direction. Considering that both stages of tectonic activities in the present invention involve thrust activities and have the accumulation of two-stage thrust activities, the width of the model in the thrust direction should accommodate the deformation range of the reverse fault. The first-stage thrust activity requires a pre-existing fault to control the tectonic deformation range. In the present invention, discrete element numerical simulation means are used, and the above boundary conditions are all established by building baffles to construct the model framework. The discrete element numerical simulation means mainly generate pressure on the internal simulated formation by setting the boundary geometric shape of the model and endowing the boundary baffles with motion attributes to cause displacement, and the internal stress action is the reason for its tectonic deformation.

[0077] Specifically, Figure 1 shows the boundaries set in the example of the present invention, including the pre-existing thrust fault plane with a preset angle of the basement, partial side baffles on the hanging wall of the fault, partial side baffles on the footwall of the fault, partial bottom plates on the hanging wall of the fault, and partial bottom plates on the footwall of the fault, as well as the inclined baffle set to ensure that the particles of the simulated formation do not leak during the second-stage compressional-shear movement.

[0078] To more accurately represent the three-dimensional geometric shape of the model, a three-dimensional coordinate system (XYZ) is added to the example model of the present invention. Among them, the extension direction of the X-axis is the width direction, the extension direction of the Y-axis is the length direction, and the extension direction of the Z-axis is the height direction.

[0079] Exemplarily, set the length, width, and height of the model boundary (corresponding to the y-axis, x-axis, and z-axis directions respectively) to be 8.0 m, 7.0 m, and 3.0 m, where:

[0080] The base preset thrust fault plane ( Figure 1 in ①) has an inclination angle of 45°, a height of 0.5 m, a width of 0.5 m, and extends 8.0 m in length. The footwalls of the hanging wall and the footwall of the fault are set on the X0Y plane ( Figure 2 in ④ and ⑤). The length of the footwall of the hanging wall is 8.0 m and the width is 4.0 m; the length of the footwall of the footwall is 8.0 m and the width is 3.0 m. The height of the side baffle is set to 3.0 m. The front and rear side baffles of the hanging wall are trapezoidal, parallel to the preset thrust fault plane, and fit with the front and rear triangular side baffles of the footwall (height 3.0 m, width 3.0 m). The lengths of the left and right side baffles of both plates are set to 8.0 m and the height is set to 3.0 m. In particular, for the gap caused by the strike-slip displacement amount set in the second-phase compressional-shear movement, an inclined baffle that grows synchronously with the strike-slip speed needs to be set between the front and rear side baffles of the upper and lower plates. Its inclination angle is 45°, height is 3.0 m, and width is 3.0 m, as shown by the baffle in Figure 2 ⑥.

[0081] In all the baffles described in the embodiments of the present invention, velocities can be assigned in three-dimensional directions. The tectonic activities in the study area are simulated through the movement of the baffles, and then the deformation characteristics of the internal simulated sedimentary strata are mainly observed.

[0082] Furthermore, in step S2, according to the actual sedimentary strata characteristics of the study area, the simulated strata are determined, that is, the mesoscopic parameters of the particles in the discrete element numerical simulation. These include, but are not limited to, particle size, intergranular porosity, particle density, and mesoscopic parameters of the contact model acting between particles (such as Young's modulus, friction coefficient, rolling resistance coefficient, and normal and tangential bonding strengths).

[0083] In the embodiments of the present invention, the above-mentioned parameters are assigned according to the empirical formulas given by predecessors for the particle parameters and macroscopic deformation parameters applicable to discrete element numerical simulation.

[0084] The target study area is the Kelamayi-Baikouquan fault zone, which is developed in front of the Zhayier Mountains. The base is in unconformable contact with the overlying strata, and the seismic profile shows an asymmetric positive flower structure. The Carboniferous system of the base develops the Lower Carboniferous Xibeikulas Formation, the Lower Carboniferous-Upper Carboniferous Baogutu Formation, and the Upper Carboniferous Tailgula Formation from bottom to top, and the lithology is volcanic rock. The Jurassic, Cretaceous and other strata deposited above are all clastic rocks.

[0085] Specifically, the mechanical parameters of the materials used in the physical simulation sandbox experiment are first determined, the microscopic parameters are calibrated according to the macroscopic parameters based on the theoretical model, and then the parameters are fine-tuned according to the actual pre-simulation results. For example, the internal friction angle of loose quartz sand is about 30°, so the rolling friction linear model is used. The macroscopic internal friction angle is controlled by the particle friction coefficient μ and the rolling resistance coefficient μr. Through the benchmark model test, the discrete element numerical simulation particle friction coefficient μ and rolling resistance coefficient μr that meet the rock Coulomb-Moore fracture criterion are finally obtained to be 0.6 and 0.6 respectively.

[0086] In the example of the invention, a homogeneous brittle simulated stratum is filled, and its particle radius, density, porosity, and Young's modulus are 0.035m, 2600kg / m3, 0.15, and 20Mpa, respectively. The overall particle radius statistics conform to the Gaussian distribution, and the confidence interval is 25%.

[0087] Furthermore, a simulated stratum is laid within the set range, and the particles with the above-mentioned properties and parameters are tightly filled within the distribution range of the simulated stratum. The example of the present invention mainly involves the structural deformation of the sedimentary stratum above the base, so only a simulated stratum with a thickness of 0.5m is laid within the model framework, and the initial filling range is 8.0m*7.0m*0.5m. In order to more clearly identify the fault characteristics caused by the strike-slip displacement on the plane, a layer of reference lines is set on the surface of the simulated stratum, with a width of about one particle diameter (0.07m), extending along the X-axis direction, a length of 7.0m, and an interval of 0.5m. In the example of the present invention, a total of 15 black reference lines ( Figure 3 black particles).

[0088] Furthermore, in order to facilitate identification of deformation features on the cross section, the simulated strata are grouped in the present invention example, and particles in each group are displayed alternately in black and white. Figure 4 In the figure, the simulated stratum with a thickness of 0.5 m is evenly divided into small layers with a thickness of 0.1 m vertically, and white and black are displayed alternately from bottom to top, among which the particles within the reference line are displayed black.

[0089] In step S3, the thrust tectonic movement is simulated by assigning the corresponding baffle velocity. In the numerical simulation, the displacement and velocity of the particles are first reset to zero before the push plate is assigned a velocity.

[0090] Specifically, the thrust movement is achieved by the movement of the fault hanging plate module, so the baffles selected for movement are the pre-existing thrust fault surface, the side baffles of the fault hanging plate and the bottom plate of the hanging plate with a preset angle ( Figure 1 The lower plate is kept stationary, and the speed in all three directions is set to 0.0 m / s.

[0091] Specifically, set the speed of the moving baffle to perform a reverse thrust movement along a preset 45° angle. There are two moving components in the X and Z directions. According to trigonometric functions, the speed magnitudes in the two moving directions are the same. The speeds of the No. ①, ②, and ④ baffles are set such that the moving speed in the X direction is -0.01 m / s and the moving speed in the Z direction is 0.01 m / s. Set the extrusion amount in the X direction to 0.25 m, and the movement lasts for 25 s. Save the result of the last step of operation. After the first-stage reverse thrust movement ends, the total uplift amount of the hanging wall part is 0.25 m, and the

[0092] extrusion amount in the X direction is 0.25 m. After the first-stage reverse thrust occurs along the 45° fault plane, low-angle reverse thrust faults parallel to the fault plane develop in the footwall along the fault plane. The roots converge on the footwall of the pre-existing fault plane, and the reverse thrust faults developed in the hanging wall converge at a high angle on the surface of the hanging wall base of the fault plane, and the deformation zone develops in a fan shape.

[0093] In step S4, the second-stage compressional-shear tectonic movement is simulated by setting the speed of the model boundary baffle. Different from the above reverse thrust movement, the compressional-shear movement involves more strike-slip displacement in the Y direction. Therefore, in the second-stage compressional-shear movement, it can be decomposed into the superposition of the reverse thrust movement and the strike-slip movement of the baffle on the hanging wall of the fault, and the strike-slip movement of the baffle on the footwall is increased compared with that in step S3. Similarly, before the speed is given to the push plate that saves the model again after the end of step S3, the displacement and speed of the particles are reset to zero again.

[0094] Exemplarily, in the example of the present invention, the strike-slip movement is set as a left-lateral strike-slip system.

[0095] Exemplarily, in the second-stage compressional-shear movement of the example of the present invention, the ratio of the reverse thrust amount to the strike-slip amount is set to 1:6. Accordingly, the baffle speeds are set as follows (X, Y, Z): For the preset pre-existing fault plane, the hanging wall side baffle, and the hanging wall floor, they are (0.01 m / s, 0.03 m / s, 0.01 m / s); for the footwall side baffle and the footwall floor, they are (0.01 m / s, -0.03 m / s, 0.01 m / s). Especially in step S4, the growth speeds of the diagonal baffles on both sides of the Y axis between the two plates need to be set to the strike-slip speeds of the two plates (0.03 m / s) (such as Figure 2 ).

[0096] Specifically, after the model starts the second-stage compressional-shear movement, save the model results every 1 s for the study of tectonic evolution. The model runs for a total of 25 steps. The displacement amount in the X-axis direction is -0.25 m, the uplift amount in the Z-axis is 0.25 m, and the relative strike-slip displacement amount between the two plates is 1.5 m.

[0097] In step S5, a comparative study is carried out based on the final model results after the two-stage tectonic movement and the actual study area, and the tectonic evolution process of the study area is speculated with the help of the saved intermediate steps.

[0098] Specifically, in the simulation experiment of compression-torsion superposition thrust, as Figure 3 , the particle contact force (contact force_Y) in the strike-slip direction is extracted for display. According to the Mohr-Coulomb failure criterion: the shear fracture angle θ (shear fracture included angle) often appears at a relationship with the principal stress σ1 axis of θ = 45° - φ / 2, [φ (internal friction angle of rock)]. The internal friction angle of the homogeneous simulated formation is a fixed value, and the shear fracture generated under compression-torsion stress can be explained by the particle contact force in the Y direction.

[0099] Furthermore, the plane deformation results of the model results in the compression-torsion stage are analyzed: when the unilateral strike-slip amount is 0.4 m: in the top view, the reverse thrust fault on the hanging wall boundary developed by the first-stage thrust activity is parallel to the pre-existing fault. The shear fractures generated by the strike-slip movement appear on the hanging wall of the reverse thrust fault. The number of developed R fractures is small, and there is a large included angle with the pre-existing fault plane of the basement; when the unilateral strike-slip amount is 0.6 m: in the final evolution stage of the model, the included angle of the R fracture becomes smaller, and it gradually develops along the pre-existing reverse thrust fault plane into a trend of a main displacement zone (PDZ). Especially in the left side of the model, the "S"-shaped R fracture evolves maturely; finally, it is observed that: the high strike-slip displacement generates a squeezing amount at the model boundary. Obliquely arranged boundary reverse faults are observed to be connected with the reverse thrust fault on the hanging wall boundary on the plane. In the final evolution stage, it is nearly parallel to the pre-existing fault plane, and together with the similarly nearly parallel P fractures on the hanging wall of the model, it forms a nearly linear PDZ. The fractures developed near the boundary reverse fault are difficult to distinguish under the state of high strike-slip amount.

[0100] Furthermore, as Figure 4 , on the cross-sectional slice perpendicular to the Y axis of the model results: the root of the reverse thrust fault on the hanging wall converges at the middle and lower position of the pre-existing 45° fault plane, and the reverse thrust fault develops upward at a low angle. The root of the high-angle reverse thrust fault on the hanging wall converges at the top of the pre-existing fault plane, jointly forming a "half flower-shaped" structure. The envelope lines of the deformed areas of the three models on the cross-section are basically coincident.

[0101] Furthermore, as Figure 5As shown, the planar fault distribution of the compression-torsion superimposed thrust simulation results in the invention example is compared with the distribution characteristics of the Cretaceous bottom interface faults in the Karamay-Baikouquan area: the fault arrangement in the Karamay-Baikouquan fault zone indicates right-side strike-slip movement, and the second phase of the tectonic movement in this compression-torsion superimposed thrust model is set as left-side strike-slip movement. In order to make the numerical simulation results more consistent with the actual geological data, the planar fault distribution in the numerical simulation results is mirrored. The branch faults in the Karamay-Baikouquan fault zone are arranged in an en-echelon arrangement on both sides of the main fault. The main thrust fault in the compression-torsion superimposed thrust model also has a strike-slip property. In the numerical simulation results, the secondary faults are arranged in a left-step en-echelon arrangement and developed on one side of the main thrust fault. Similarly, at the tail end of the main fault, a broom-shaped structure in the strike-slip fault system is developed, such as the northern end of the Kebai fault zone. The numerical simulation results also produce a secondary thrust fault at the tail end, which forms a broom-shaped structure with the main thrust fault. In the section, as Figure 5 As shown in Figure 1, the seismic profile in the study area shows an asymmetric positive flower-shaped structure. The main strike-slip fault is steeply inclined, and the branch fault develops on one side of the main fault, showing "reverse fault displacement", reflecting the nature of compression-torsion strike-slip. Numerical simulation results show that after the compression-torsion movement, the roots of the secondary faults all converge on the pre-existing thrust fault plane, and a large-scale thrust fault develops in the footwall, which together with the secondary faults in the hanging wall form a "semi-flower-shaped structure".

[0102] Furthermore, if Figure 6 As shown, stress analysis is performed on the simulation results of compression-torsion superimposed thrust. The classic strike-slip strain ellipse shows that under the action of simple shear stress, the R rupture and its conjugate ruptures R' rupture and P rupture are respectively developed on both sides of the main rupture zone PDZ (main displacement zone of the strike-slip system). In the example of the present invention, the thrust action is increased under the action of simple shear. The law of fracture formation during the compression-torsion movement in the example of the invention is explained by the stress-strain relationship in geology: in the second phase of compression-torsion tectonic activity, the pure strike-slip tectonic deformation conforms to the deformation mode of simple shear, accompanied by the simultaneous thrust activity, which is equivalent to applying another compression force perpendicular to the direction of the strike-slip movement. At this time, the actual shear stress direction that produces the strike-slip action is equivalent to rotating counterclockwise (in a left-handed strike-slip system). The first phase of thrust activity constrains the PDZ to the upper plate parallel to the pre-existing thrust fault. The angle between the R rupture developed under the actual shear force of the strike-slip action and the pre-existing fault is greater than φ / 2.

[0103] Furthermore, it is inferred that the development of the Karamay-Baikouquan strike-slip fault zone is controlled by early pre-existing faults, the location of the surrounding fault development and the later fault structural style; the Kebai fault zone is developed under the background of compression-torsion tectonic stress, and its strike-slip faults are of thrust nature, and the thrust faults also have displacement components along the strike; and it is inferred that its early strike-slip faults also show an en echelon distribution of R ruptures, forming a large strike-slip fault zone under the continuous compression-torsion.

[0104] Example 3

[0105] In the specific embodiment 3 of applying the present invention, the compression-torsion superposed thrust tectonic deformation includes the following steps:

[0106] Step S1: Based on the research purpose, construct appropriate model boundary conditions and divide them into several modules with different motion conditions;

[0107] Step S2: Based on the actual sedimentary formation characteristics of the target research area, determine the mesoscopic contact parameters of the simulated formation;

[0108] Step S3: Based on the research purpose, design the first-stage pre-existing thrust tectonic movement. By setting the model boundary velocity, make it undergo thrust movement to generate pre-existing thrust faults;

[0109] Step S4: On the basis of the first-stage thrust tectonic movement, design the second-stage compression-torsion tectonic movement. The motion setting of the model boundary in this step is different from the thrust in the previous step;

[0110] Step S5: Finally, conduct tectonic analysis based on the model results under the two-stage tectonic movements.

[0111] Specifically, as in Example 2, set the model boundary. It includes a pre-existing thrust fault plane with a preset angle of the basement, partial baffles on the hanging wall of the fault, partial baffles on the footwall of the fault, partial bottom plates on the hanging wall of the fault, and partial bottom plates on the footwall of the fault, as well as the oblique baffles set to ensure that the particles in the model do not overflow during the second-stage compression-torsion movement. The coordinate system is the same as in Example 2.

[0112] Exemplarily, set the length, width, and height of the model boundary (corresponding to the y-axis, x-axis, and z-axis directions respectively) to be 10.0 m, 7.0 m, and 3.0 m, where:

[0113] The pre-existing thrust fault plane of the basement ( Figure 1 ① in it) has an inclination angle of 45°, a height of 0.5 m, a width of 0.5 m, and extends 10.0 m in length. The bottom plates of the hanging wall and the footwall of the fault are set on the X0Y plane ( Figure 2 ④ and ⑤ in it). The length of the bottom plate of the hanging wall is 10.0 m and the width is 4.0 m; the length of the bottom plate of the footwall is 10.0 m and the width is 3.0 m. The height of the side baffles is set to 3.0 m. The front and rear side baffles of the hanging wall are trapezoidal, parallel to the preset thrust fault plane, and fit with the front and rear triangular side baffles of the footwall (height 3.0 m, width 3.0 m). The lengths of the left and right side baffles on both sides are set to 10.0 m and the height is set to 3.0 m. Especially for the gap caused by the strike-slip displacement amount set during the second-stage compression-torsion movement, an oblique baffle that grows synchronously with the strike-slip speed needs to be set between the front and rear side baffles of the upper and lower plates. Its inclination angle is 45°, height is 3.0 m, and width is 3.0 m, as shown by the baffle ⑥ in Figure 2 it.

[0114] In the examples of the present invention, all baffles can be given velocities in three-dimensional directions. The tectonic activities in the study area are simulated through the movement of the baffles, and then the deformation characteristics of the internal simulated sedimentary strata are mainly observed.

[0115] Furthermore, the parameters of the simulated strata are set. Further, within the set range, the simulated strata are laid, and the particles with the above-mentioned properties and parameters are tightly filled within the distribution range of the simulated strata. In the examples of the present invention, the tectonic deformation of the sedimentary strata above the basement is mainly involved. Therefore, only a 0.5 m thick simulated strata is laid within the model framework, and the initial filling range is 10.0 m * 7.0 m * 0.5 m. To more clearly identify the fault characteristics caused by the strike-slip displacement on the plane, a layer of reference lines is set on the surface of the simulated strata. The width of the reference lines is about one particle diameter (0.07 m), extending along the X-axis direction, with a length of 7.0 m and an interval of 0.5 m. A total of 15 black reference lines ( Figure 3 black particles) are set in the examples of the present invention.

[0116] Furthermore, to facilitate the identification of the deformation characteristics in the cross-section, in the examples of the present invention, the simulated strata are grouped, and the particles in each group are displayed with black and white colors interspersed. Specifically, as Figure 4 shown, the 0.5 m thick simulated strata are equally divided into small layers with a thickness of 0.1 m vertically, and are displayed alternately with white and black from bottom to top, and the particles within the reference lines are displayed in black.

[0117] In step S3, the thrust tectonic movement is simulated by giving corresponding velocities to the baffles. In the numerical simulation, before the pushing plate is given a velocity, the displacements and velocities of the particles are first cleared to zero.

[0118] Specifically, the thrust movement is realized through the movement of the hanging wall module of the fault. Therefore, the selected moving baffles are the pre-existing thrust fault plane with a preset angle, the side baffle of the hanging wall of the fault, and the bottom plate of the hanging wall ( Figure 1 baffles ①, ②, and ④ shown in the figure). The footwall part remains stationary, and the velocities in the three-dimensional directions are all set to 0.0 m / s.

[0119] Specifically, the velocities of the moving baffles are set to perform thrust movement along the preset 45° angle. There are two movement components in the X direction and the Z direction. According to trigonometric functions, the velocity magnitudes in the two movement directions are the same. The velocities of baffles ①, ②, and ④ are set such that the movement velocity in the X direction is -0.01 m / s and the movement velocity in the Z direction is 0.01 m / s. The extrusion amount in the X direction is set to 0.25 m, and the movement lasts for 25 s, and the result of the last step of the operation is saved. After the first-stage thrust movement ends, the total uplift amount of the hanging wall part is 0.25 m, and in the X direction

[0120] The extrusion amount is 0.25 m. After the thrust along the 45° fault plane in the first stage, low-angle thrust faults parallel to the fault plane developed in the hanging wall of the fault plane, converging at the root in the footwall of the pre-existing fault plane. The thrust faults developed in the hanging wall converged at a high angle on the surface of the uplifted basement of the fault plane, and the deformation zone developed in a fan shape.

[0121] In step S4, the second-stage compressional-shear tectonic movement is simulated by setting the velocity of the model boundary baffle. Different from the above thrust movement, the compressional-shear movement involves more the strike-slip displacement in the Y direction. Therefore, in the second-stage compressional-shear movement, it can be decomposed into the superposition of the thrust movement and the strike-slip movement of the baffle on the hanging wall of the fault, while the baffle on the footwall increases the strike-slip movement compared with that in step S3. Similarly, before the push plate that saved the model at the end of step S3 is given a velocity again, the displacement and velocity of the particles are reset to zero.

[0122] Exemplarily, in the example of the present invention, the strike-slip movement is set as a right-lateral strike-slip system.

[0123] Exemplarily, in the second-stage compressional-shear movement in the example of the present invention, the ratio of the thrust amount to the strike-slip amount is set to 1:6. Correspondingly, the baffle velocities are set as follows (X, Y, Z): The pre-existing fault plane, the baffle on the hanging wall side and the hanging wall floor are set as (0.01 m / s, -0.03 m / s, 0.01 m / s); the baffle on the footwall side and the footwall floor are set as (0.01 m / s, 0.03 m / s, 0.01 m / s). Especially in step S4, the growth velocities of the diagonal baffle between the two plates on both sides of the Y axis need to be set as the strike-slip velocities of the two plates (-0.03 m / s) (such as Figure 2 ).

[0124] Specifically, after the model starts the second-stage compressional-shear movement, the model results are saved every 1 s for the study of tectonic evolution. The model runs for a total of 40 steps, the displacement in the X-axis direction is -0.4 m, the uplift amount in the Z-axis is 0.4 m, and the relative strike-slip displacement between the two plates is 2.4 m.

[0125] In step S5, a comparative study is carried out based on the final model results after the two-stage tectonic movement and the actual study area, and the tectonic evolution process of the study area is inferred with the help of the saved intermediate steps.

[0126] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0127] Except for the technical features described in the specification, all are well-known technologies to those skilled in the art.

Claims

1. Discrete element simulation method for compression-torsion superposed thrust tectonic deformation, characterized in that The discrete element simulation method for the compression-torsion superposed thrust tectonic deformation includes: Step 1: Construct appropriate model boundary conditions and divide them into several modules with different motion conditions. Step 2: Determine the mesoscopic contact parameters of the simulated strata based on the actual sedimentary strata characteristics of the target research area. Step 3: Design the first-phase pre-existing thrust tectonic movement. Step 4: Design the second-phase compression-torsion tectonic movement based on the first-phase thrust tectonic movement. Step 5: Conduct tectonic analysis based on the model results under the two-phase tectonic movements.

2. The discrete element simulation method for the compression-torsion superposed thrust structural deformation according to claim 1, wherein In Step 1, construct motion modules that can simultaneously carry out motions in three-dimensional space, including a pre-existing thrust fault plane with a preset angle at the basement, partial side baffles on the hanging wall of the fault, partial side baffles on the footwall of the fault, partial floor on the hanging wall of the fault, and partial floor on the footwall of the fault.

3. The discrete element simulation method for compressive-torsional superposed thrust structural deformation according to claim 2, characterized in that In Step 1, considering the gap formed between the hanging wall and the footwall when the strike-slip amount of the designed model occurs, an inclined baffle needs to be set between the two motion modules to ensure that no particles are lost during the second-phase movement of the model.

4. The discrete element simulation method for compression-torsion superposed thrust structural deformation according to claim 3, wherein In Step 1, determine the three-dimensional geometric parameters of the model according to the range of deformation expected to occur in the simulated strata, specifically referring to the inclination angle of the preset fault plane, the length of the preset fault plane, the lengths of the hanging wall and footwall parts, the width and height, and the corresponding lengths and widths of the floor parts of the hanging wall and footwall.

5. The discrete element simulation method for compressive-torsional superposed thrust structural deformation according to claim 1, characterized in that In Step 2, in the discrete element numerical simulation, change the macroscopic deformation performance of the model according to the characteristics of the particles and the wall itself and the setting of the mesoscopic parameters of the contact model between them.

6. The discrete element simulation method for compressive-torsional superposed thrust structural deformation according to claim 5, characterized in that In Step 2, combined with the sedimentary strata properties of the actual research area, give the mesoscopic parameters of the particles in the discrete element numerical model through the empirical formula between the macroscopic parameters and the mesoscopic parameters.

7. The discrete element simulation method for the compression-torsion superposition thrust structural deformation according to claim 6, wherein In Step 2, divide the simulated strata as needed, and group and display the simulated strata in different colors, including the vertical grouping of homogeneous strata. In addition, differential display of simulated strata with different characteristics can also be carried out.

8. The discrete element simulation method for compression-torsion superposed thrust structural deformation according to claim 1, characterized in that In Step 3, determine the model baffles that move in the first phase. The thrust movement is formed by the upward movement of the hanging wall module along the preset fault plane, while the footwall module is controlled to remain fixed.

9. The discrete element simulation method for compressive-torsional superposed thrust structural deformation according to claim 8, characterized in that, In Step 3, the baffles that need to be given motion speeds include three parts: the preset fault plane, the side baffle of the hanging wall, and the floor of the hanging wall.

10. The discrete element simulation method for compression-torsion superposed thrust structural deformation according to claim 9, wherein In Step 3, due to the existence of the preset fault, the real displacement occurs parallel to the preset fault plane. When setting the speed, it needs to be decomposed in the horizontal direction perpendicular to the strike and the vertical direction, and attention should be paid to the matching relationship of its values in trigonometric functions.

11. The discrete element simulation method for the compression-torsion superposed thrust structural deformation according to claim 1, wherein In Step 4, the compression-torsion movement is the simultaneous occurrence of strike-slip movement and thrust movement. Therefore, the thrust movement setting is the same as that in the previous phase, and the motion baffles involved include three parts: the preset fault plane, the side baffle of the hanging wall, and the floor of the hanging wall. The strike-slip movement is the relative movement between the hanging wall and footwall modules, and the speed setting of this part involves the side baffles and floors of both the hanging wall and the footwall.

12. The discrete element simulation method for compression-torsion superposition thrust structural deformation according to claim 11, characterized in that, In Step 4, considering the gap generated by the relative displacement caused by the strike-slip movement between the hanging wall and footwall modules, the growth of the inclined baffles between the hanging wall and footwall modules including their side baffles and floors is also involved to compensate for the generated gap and ensure that no particles are lost.

13. The discrete element simulation method for compression-torsion superposed thrust structural deformation according to claim 12, characterized in that In step 4, when setting the velocity of the second-phase compressional-shear movement, the movement is decomposed in three spatial directions; the hanging-wall module includes the thrust velocity components in the horizontal direction perpendicular to the strike and the vertical direction, and the strike-slip velocity component in the horizontal direction parallel to the strike of the preset fault plane is increased; on the other hand, the footwall module is set with a strike-slip velocity component opposite to the strike-slip direction of the hanging-wall module.

14. The discrete element simulation method for compression-torsion superposed thrust structural deformation according to claim 1, characterized in that, In step 5, during the numerical simulation experiment, the results of multiple steps of the model are saved, including the results after the thrust movement is completed and the model results are saved at certain intervals during the compressional-shear movement. Based on the contact properties or grouped results of the saved model results, structural analysis is carried out according to the continuous deformation results.

15. The discrete element simulation method for the compressive-torsional superposed thrust structural deformation according to claim 14, wherein In step 5, horizontal deformation characteristics and slice analysis along the strike-slip direction of the saved model results are carried out. Due to the limitation of the calculation speed, the number of particles is not enough to fully approximate the actual sedimentary strata situation. Therefore, for the structural phenomena with obvious internal fractures in the results, it is necessary to identify and observe them with the help of contact forces.

16. The discrete element simulation method for compressional-torsional superposed thrust structural deformation according to claim 15, wherein In step 5, structural interpretation is carried out on the simulated deformation results, including the combination characteristics of faults on the plane and profile slices; and quantitative statistical analysis is carried out on them, and the actual stress action mechanism during the deformation process is restored according to their geometric manifestations; furthermore, a reasonable structural evolution process is proposed for the study area and theoretical support is provided for it.

17. Discrete element simulation system for compressive-torsional superposed thrust tectonic deformation, characterized in that, The discrete element simulation system for compressional-shear superimposed thrust structural deformation quantitatively analyzes and infers the structural evolution process of the study area by using the discrete element simulation method for compressional-shear superimposed thrust structural deformation described in any one of claims 1-16.

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