Physical simulation device of superimposed extrusion and tension stress field and experimental method thereof

Abstract

The application discloses a physical simulation device of superposition of extrusion and tensile stress field, comprising a power device, a sand box bin and an automatic sand distribution device, wherein the automatic sand distribution device is located above the sand box bin, and the power device is arranged at the bottom side of the sand box bin, and further discloses an experimental method of the physical simulation device of superposition of extrusion and tensile stress field. The application is suitable for the technical field of structural geology and can simulate the structural development of strata under the background of extrusion or tensile stress by adopting the power device to control the sand box to perform extrusion and tensile movement. The problem of frictional resistance of sand layer is solved by using the synchronously active side plate of the sand box. Through forward modeling and reproduction, the data collection of the development process of deep structure and the influence on shallow structure under the action of multi-period extrusion and tensile stress field is realized, and the application has universal applicability and operability.

Description

Technical Field

[0001] This invention belongs to the field of structural geology technology, specifically a physical simulation device and experimental method for superimposed compression and tension stress fields. Background Technology

[0002] Currently, a systematic understanding of the characteristics and formation mechanisms of deep tectonic deformation, basin-controlling features, and basin superposition and evolution is lacking, significantly hindering deep oil and gas exploration. Physical simulation experiments can verify the influence and controlling factors of natural deformation and are an effective way to forward model and reproduce tectonic development processes, playing a crucial role in the theoretical and practical application research of tectonic deformation.

[0003] Current structural physics simulation experiments can only complete the simulation of structural evolution in stages. For example, application number 201811323997.9 describes a diapiric physics simulation experimental device and method under hypergravity conditions. The device includes an experimental chamber and a diapiric power device. The experimental chamber consists of a long push plate, a moving plate, and a bottom plate. The moving plate includes a fixed moving plate and a telescopic moving plate connected to it. Experimental materials are placed inside the experimental chamber. Under the action of the diapiric power device, the long push plate moves back and forth, and the telescopic moving plate performs telescopic movements to compress and deform the experimental materials inside the experimental chamber. The experimental device of this invention, under constant gravity conditions, completes the arrangement of experimental materials within the deep structural physics simulation experimental chamber. Under centrifugal force conditions, it automatically controls the diapiric power device of the structural physics simulation experimental chamber, enabling the chamber to complete the deep structural physics simulation experiment. The study of the dynamic structural deformation physical simulation process within the experimental chamber provides researchers with an instant model of the geological structural evolution process.

[0004] For example, application number 201811323852.9 describes an experimental device and method for simulating strike-slip tectonic physics in a hypergravity environment. The device includes an experimental chamber and a power unit. The experimental chamber comprises a fixed baffle and two bottom plates. Each bottom plate has a movable baffle and a movable drive plate on each side, arranged in a staggered manner. The bottom of the bottom plate is mounted on a guide rail via a slider. Under the action of the power unit, each bottom plate drives its connected drive plate and movable baffle, causing the experimental material inside the chamber to deform in a staggered manner. This experimental device arranges the experimental material inside the chamber under normal gravity conditions. Under centrifugal force conditions, it automatically controls the power units on both sides of the tectonic physics simulation chamber, enabling the chamber to perform deep strike-slip tectonic physics simulation experiments, providing researchers with an instant model of geological tectonic evolution.

[0005] It can be seen that in current structural physics simulation experiments, once the compressive stress field experiment is completed, the experimental setup needs to be removed and the tensile environment experiment needs to be restarted. This makes it difficult to achieve a continuous structural evolution process, and human factors also play a significant role. In addition, the sand layer is currently pressed tightly against the glass side plate of the sand box, and the sand layer material and density are different. During the compression and tension of the sand layer, there is friction between the sand grains and the glass side plate. In particular, some wet sand layers are prone to obstruction, resulting in unclear sand layer boundaries in the frontal image, which greatly interferes with the analysis and measurement of experimental results. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a physical simulation device and experimental method for superimposed compression and tension stress fields.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, a physical simulation device for superimposed compression and tension stress fields includes a power unit, a sand box, and an automatic sand distribution device, wherein the automatic sand distribution device is located above the sand box and the power unit is located on the bottom side of the sand box.

[0009] The sand box is equipped with a sand box, which includes an outer box and an inner box. The outer box has open sides. The inner box includes side plates on the left and right sides, a movable plate on the front side, and a fixed plate on the rear side. The fixed plate is fixedly connected to the outer box. The movable plate is slidably connected to the outer box and connected to the power unit.

[0010] Preferably, the side panel is a glass panel with a slide bar fixedly connected to its bottom edge. The slide bar is located on the bottom surface of the outer casing, and several grooves perpendicular to the slide bar are provided on the bottom surface of the outer casing. The slide bar is slidably disposed in the grooves.

[0011] Preferably, a first slide block is provided on the bottom surface of the outer casing directly below the movable plate. The first slide block is connected to a power device and moves synchronously with the movable plate.

[0012] Preferably, both ends of the first slide block are slidably connected to slide rails, the slide rails are parallel to the slide bar, and the slide rails are provided with wedge surfaces with a certain inclination angle on the side of the slide bar. The two ends of the first slide block are also connected to telescopic rods, the ends of the telescopic rods are connected to second slide blocks, and the second slide blocks are slidably disposed on the slide bar.

[0013] Preferably, the bottom surface of the inner box is provided with rubber between the side panels.

[0014] Preferably, the rubber sheet is laid flat on the bottom surface of the inner box, with one end fixed to the fixing plate and the other end fixed to the inner box by adhesive. A wet sand layer is laid on top of the rubber sheet, and a dry sand layer is laid on top of the wet sand layer.

[0015] Preferably, a layer of glass beads is laid between the rubber sheet and the wet sand layer.

[0016] Preferably, the thickness of the glass bead layer is 0.2-0.5 cm, the thickness of the wet sand layer is 2-3 cm, and the thickness of the dry sand layer is 0.5-1 cm.

[0017] Preferably, the bottom end of the movable plate is provided with a protrusion, and the protrusion is provided with a through hole.

[0018] Preferably, a spring is provided inside the groove.

[0019] Secondly, an experimental method for a physical simulation device of superimposed compression and tension stress fields includes the following steps:

[0020] S1: Fix the rubber sheet to the experimental table, and use a power device to push the movable plate forward while keeping the rubber sheet stationary, so that the movable plate moves a certain distance at a certain speed;

[0021] S2: The structural evolution of the dry sand layer, wet sand layer and glass bead layer is observed by scanning the top plane of the sand box with a scanner after it has moved a certain distance. The structural evolution of the dry sand layer, wet sand layer and glass bead layer under compression is recorded by a camera from the front of the sand box, so that the structural physics simulation can complete the data collection of the compression experiment.

[0022] S3: After the physical simulation of the extrusion structure is completed, the raised areas on the top plane of the sand box are swept and filled with sand using an automatic sand distribution device;

[0023] S4: Unfix the end of the rubber sheet near the power device to the test bench, and fix the unfixed rubber sheet to the movable plate. Use the power device to pull the movable plate backward to generate tensile stress in the rubber sheet and maximize the tensile distance at a certain speed.

[0024] S5: Scan the top plane of the sand box with a scanner to observe the structural evolution of the dry sand layer, wet sand layer and glass bead layer after moving a certain distance. Record the structural evolution of the dry sand layer, wet sand layer and glass bead layer under tension with a camera from the front of the sand box, so that the structural physics simulation can complete the collection of tension experiment data.

[0025] S6: After the physical simulation of the tension structure is completed, the sand box is filled with sand by an automatic sand distribution device to complete one compression and tension experiment.

[0026] Preferably, in steps S1 and S4, the moving speed is set to 0.02 to 0.08 mm / s, and the extrusion distance in step S1 is 6 to 10 cm.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] In this invention, in terms of structural physics simulation experiments, the structural physics simulation device uses a power device to control the sand box to perform compression and tension movements, which can simulate the structural development of strata under compression or tension stress background. The synchronously moving side plates of the sand box solve the problem of frictional resistance between the sand layer and the sand. Through forward modeling and reproduction under the action of multiple compression and tension stress fields, the data acquisition of the development process of deep structures and their impact on shallow structures is realized, which has universal applicability and operability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the sand box structure in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the structure of the bottom surface of the sand box in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the cross-section of the sand box in an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of the experimental cross-sectional effect of an embodiment of the present invention;

[0034] Figure 6 This is a simulation experiment diagram of a single-fracture depression according to an embodiment of the present invention;

[0035] Figure 7 This is a simulation experiment diagram of the double-fracture depression in an embodiment of the present invention.

[0036] Reference numerals in the attached drawings: 1. Power unit; 2. Sand box; 3. Automatic sand distribution device; 4. Inner box; 41. Slide groove; 42. Slide rail; 421. Wedge surface; 43. First slider; 44. Telescopic rod; 45. Second slider; 5. Inner box; 51. Movable plate; 511. Protrusion; 52. Side plate; 521. Slide bar; 53. Fixed plate; 6. Rubber sheet; 7. Wet sand layer; 8. Dry sand layer; 9. Glass bead layer. Detailed Implementation

[0037] The specific embodiments of the present invention are described in detail below.

[0038] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 10–50 is listed for a specific parameter, it is also expected that ranges of 10–40 and 20–50 are also included. Furthermore, if the minimum range values ​​are 1 and 2, and the maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0–5" means that all real numbers between "0–5" have been listed herein; "0–5" is merely a shortened representation of these numerical combinations.

[0039] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0040] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0041] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0042] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0043] Unless otherwise specified, the reaction will proceed under normal temperature and pressure conditions.

[0044] Unless otherwise specified, all parts or percentages are by weight or by weight percentage.

[0045] In this invention, all the substances used are known substances that can be purchased or synthesized by known methods.

[0046] In this invention, all the devices or equipment used are conventional devices or equipment known in the art and are readily available.

[0047] The following embodiments further illustrate specific implementations of the physical simulation device and experimental method for superimposed extrusion and tension stress fields according to the present invention. The physical simulation device and experimental method for superimposed extrusion and tension stress fields according to the present invention are not limited to the descriptions in the following embodiments.

[0048] Example 1:

[0049] like Figures 1 to 4 As shown, a physical simulation device for superimposed compression and tension stress fields includes a power unit 1, a sand box 2, and an automatic sand distribution device 3. The automatic sand distribution device 3 is located above the sand box 2, and the power unit 1 is located on the bottom side of the sand box 2.

[0050] The sand box 2 contains a sand box, which consists of an outer box 4 and an inner box 5. The outer box 4 has open sides. The inner box 5 consists of side plates 52 on both sides, a movable plate 51 on one side, and a fixed plate 53 on the other side. The fixed plate 53 is fixedly connected to the outer box 4. The movable plate 51 is slidably connected inside the outer box 4 and connected to the power device 1. The power device 1 is used to drive the movable plate 51 to move at a low speed. The power device 1 can be composed of a motor and a high-precision ball screw pair.

[0051] All side panels 52 are glass plates, and their bottom edges are fixedly connected to slide bars 521. The slide bars 521 are located on the inner bottom surface of the outer housing 4, and several slide grooves 41 perpendicular to the slide bars 521 are provided on the inner bottom surface of the outer housing 4. The slide bars 521 are slidably disposed in the slide grooves 41. A first slide block 43 is also provided on the inner bottom surface of the outer housing 4, directly below the movable plate 51. The first slide block 43 is also connected to the power device 1 and moves synchronously with the movable plate 51. The two ends of the first slide block 43 are slidably connected to a slide rail 42. The slide rail 42 is parallel to the slide bars 521, and the slide rail 42 is provided with a wedge surface 421 with a certain inclination angle on the side of the slide bars 521. The two ends of the first slide block 43 are also connected to telescopic rods 44 (the first slide block 43 is connected to the telescopic rods 44 through a U-shaped block passing under the slide rails 42). The end of the telescopic rods 44 is connected to a second slide block 45, which is slidably disposed on the slide bars 521.

[0052] Example 2:

[0053] like Figures 1 to 4As shown, a physical simulation device for superimposed compression and tension stress fields is similar to that in Embodiment 1 in other aspects. The bottom surface of the inner box 4 is provided with rubber 6 between the side plates 52. Specifically, the rubber 6 is laid flat on the bottom surface of the inner box 4 and one end is fixed to the fixing plate 53, while the other end is fixed to the inner box 4 by adhesive. A wet sand layer 7 is laid on top of the rubber 6, and a dry sand layer 8 is laid on top of the wet sand layer 7.

[0054] Example 3:

[0055] like Figures 1 to 4 As shown, a physical simulation device for superimposed compression and tension stress fields is presented. The other structures are similar to those in Example 1, with a glass bead layer 9 laid between the rubber sheet 6 and the wet sand layer 7.

[0056] Example 4:

[0057] like Figures 1 to 4 As shown, a physical simulation device for superimposed compression and tension stress fields is presented. The other structures are similar to those in Example 1, except that the thickness of the glass bead layer 9 is set to 0.2 cm, the thickness of the wet sand layer 7 is set to 2 cm, and the thickness of the dry sand layer 8 is set to 0.5 cm.

[0058] Example 5:

[0059] like Figures 1 to 4 As shown, a physical simulation device for superimposed compression and tension stress fields is presented. The other structures are similar to those in Example 1, except that the thickness of the glass bead layer 9 is set to 0.4 cm, the thickness of the wet sand layer 7 is set to 2.5 cm, and the thickness of the dry sand layer 8 is set to 0.8 cm.

[0060] Example 6:

[0061] like Figures 1 to 4 As shown, a physical simulation device for superimposed compression and tension stress fields is presented. The other structures are similar to those in Example 1, except that the thickness of the glass bead layer 9 is set to 0.5 cm, the thickness of the wet sand layer 7 is set to 3 cm, and the thickness of the dry sand layer 8 is set to 1 cm.

[0062] Example 6:

[0063] like Figures 1 to 4As shown, a physical simulation device for superimposed compression and tension stress fields is used. Based on the actual geological conditions of the research area, the length-to-width ratio of the inner box 5 is generally chosen to be approximately 2:1. The movable plate 51 is connected to the power device 1. A rubber sheet 6 is laid on the experimental platform, serving as the primary carrier for power transmission. The continuous experimental process is mainly achieved through the fixing of the rubber sheet 6. A 0.3cm layer of glass beads 9 is laid on top of the rubber sheet 6 to simulate a high-conductivity, low-velocity body within the crust, i.e., a separation zone, allowing stress to be better transferred to the sand layer above. Based on the properties and similarity principles of the strata, a 2cm layer of wet sand 7 is laid on top of the glass bead layer 9, and a 1cm layer of dry sand 8 is laid on top of the wet sand layer 7 to simulate the Paleozoic strata and the upper crust.

[0064] The compression experiment begins first. At this time, one end of the rubber sheet 6 is attached to the experimental table. The moving plate 51 is pushed forward by the power device 1, while the rubber sheet 6 remains stationary. Due to the forward movement of the moving plate 51, compression is generated. The forward speed is 0.05 mm / s, and the forward movement is 10 cm. The structural evolution process of the dry sand layer 8, wet sand layer 7, and glass bead layer 9 under compression is recorded from the front and top surfaces by the camera set on the side of the outer box 4 and the scanner set on the top, respectively, so that the structural physics simulation can complete the data collection of the compression experiment.

[0065] After the physical simulation of the extrusion structure is completed, the raised areas on the top plane of the inner box 5 are filled with sand using the automatic sand-spreading device 3. The left rubber sheet 6 is removed from the experimental table and fixed to the movable plate 51 (the bottom of the movable plate 51 has a protrusion 511 with through holes, which can be nailed in to connect the movable plate 51 to the rubber sheet 6). The tension experiment begins. Since the movable plate 51 is connected to the bottom rubber sheet 6, the power device 1 pulls the movable plate 51 to move it. The movable plate 51 pulls the rubber sheet 6, generating tensile stress. The tension of the rubber sheet 6 also puts the glass bead layer 9 on top of the rubber sheet 6 into a tensile environment. Due to the physical properties of glass beads, they are prone to stretching and sliding. The wet sand layer 7 on top of the glass bead layer 9 is also in a tensile environment under the stress transmission of the glass bead layer 9. This way of laying the glass bead layer 9 is much better than laying the wet sand layer 7 directly on the rubber sheet 6. The power device 1 drives the movable plate 51 to move backward, so that the rubber sheet 6 generates tensile stress. The entire sand box is also in a tensile environment at a speed of 0.05 mm / s until the tensile distance is maximized. The structural evolution process of the front of the sand box under tensile state is recorded by a camera. Finally, the sand box is filled with sand at the top of the sand box by the automatic sand spreading device 3 to complete one compression and tension experiment.

[0066] During the above experiment, the first slide block 43 at the bottom moves synchronously with the movable plate 51. When the first slide block 43 moves, the telescopic rod 44, under the action of the wedge surface 421, will push the second slide block 45 and the slide bar 521 to move along the slide groove 41 as a whole. That is, during the compression and tensioning process, the side plate 52 is always separated from the side of the inner sand layer and maintains a small gap with the sand layer. The size of the gap is determined by the inclination of the wedge surface 421. This gap ensures that there is no friction or sliding between the side plate 52 and the sand layer, and will not affect the sand layer and cause it to collapse, so that the sand layer interface has a clear and accurate boundary. A spring is installed in the slide groove 41 to keep the telescopic rod 44 in contact with the wedge surface 421.

[0067] In terms of structural physics simulation experiments, the structural physics simulation device uses a power device 1 to control the sand box to perform compression and tension movements, which can simulate the structural development of strata under compression or tension stress background. Through forward modeling and reproduction under the action of multiple compression and tension stress fields, the data acquisition of the development process of deep structures and their impact on shallow structures has been realized, which has universal applicability and operability.

[0068] Experimental results show that, Figure 5 As shown, the normal fault cuts the reverse fault plane, but does not reverse along the pre-existing reverse fault plane. Under the later extensional modification, a single-fault depression develops; as... Figure 6 , 7 As shown, when the baffle stretching rate decreases to 0.02 mm / s, the sand body develops a double-fracture depression, and other structural deformations are similar to those in the aforementioned experiment.

[0069] Example 7:

[0070] An experimental method for a physical simulation device of superimposed compressive and tensile stress fields includes the following steps:

[0071] S1: Fix the rubber sheet 6 on the experimental table, and push the movable plate 51 forward through the power device 1. The rubber sheet 6 remains stationary, so that the movable plate 51 moves a certain distance at a certain speed.

[0072] S2: After the top plane of the sand box is scanned by scanner 4 and moved a certain distance, the structural evolution of dry sand layer 8, wet sand layer 7 and glass bead layer 9 is recorded by camera 6 from the front of the sand box under the extrusion state, so that the structural physical simulation can complete the extrusion experiment data collection.

[0073] S3: After the physical simulation of the extrusion structure is completed, the sand-filling device 3 will be used to sweep and fill the raised areas on the top plane of the sand box.

[0074] S4: Unfix the end of the rubber sheet 6 near the power device 1 to the test bench, and fix the unfixed rubber sheet 6 to the movable plate 51. Pull the movable plate 51 backward by the power device 1 to generate tensile stress in the rubber sheet 6, and maximize the tensile distance at a certain speed.

[0075] S5: After scanning the top plane of the sand box by a scanner and moving a certain distance, the structural evolution of the dry sand layer 8, wet sand layer 7 and glass bead layer 9 is recorded by a camera from the front of the sand box under tension, so that the structural physics simulation can complete the collection of tension experiment data.

[0076] S6: After the physical simulation of the tension structure is completed, the sand box top surface depression is filled with sand by the automatic sand distribution device 3, thereby completing one compression and tension experiment.

[0077] Example 7:

[0078] An experimental method for a physical simulation device for superimposed compression and tension stress fields, the other steps are similar to those in Example 6, wherein the moving speed is set to 0.02 mm / s in steps S1 and S4, and the compression distance in step S1 is 6 cm.

[0079] Example 8:

[0080] An experimental method for a physical simulation device for superimposed compression and tension stress fields, the other steps are similar to those in Example 6, wherein the moving speed is set to 0.05 mm / s in steps S1 and S4, and the compression distance in step S1 is 8 cm.

[0081] Example 9:

[0082] An experimental method for a physical simulation device for superimposed compression and tension stress fields, the other steps are similar to those in Example 6, wherein the moving speed is set to 0.08 mm / s in steps S1 and S4, and the compression distance in step S1 is 10 cm.

[0083] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A physical simulation device for the superposition of compressive and tensile stress fields, characterized in that: It includes a power unit (1), a sand box (2), and an automatic sand distribution device (3). The automatic sand distribution device (3) is located above the sand box (2), and the power unit (1) is located on the bottom side of the sand box (2). The sand box compartment (2) is equipped with a sand box, which includes an outer box (4) and an inner box (5). The outer box (4) has a hollow side. The inner box (5) includes side plates (52) on the left and right sides, a movable plate (51) on the front side, and a fixed plate (53) on the rear side. The fixed plate (53) is fixedly connected to the outer box (4). The movable plate (51) is slidably connected inside the outer box (4) and connected to the power device (1).

2. The physical simulation device for superimposed compression and tension stress fields according to claim 1, characterized in that, The side plate (52) is a glass plate, and a slide bar (521) is fixedly connected to its bottom edge. The slide bar (521) is located on the bottom surface of the outer box (4), and several grooves (41) perpendicular to the slide bar (521) are provided on the bottom surface of the outer box (4). The slide bar (521) is slidably disposed in the groove (41).

3. The physical simulation device for superimposed compression and tension stress fields according to claim 1, characterized in that, The bottom surface of the outer casing (4) is located directly below the movable plate (51) and a first slide (43) is provided. The first slide (43) is connected to the power device (1) and moves synchronously with the movable plate (51).

4. The physical simulation device for superimposed compression and tension stress fields according to claim 3, characterized in that, The first slide block (43) is slidably connected to slide rails (42) at both ends. The slide rails (42) are parallel to the slide bar (521), and the slide rails (42) are provided with a wedge surface (421) with a certain inclination angle on the side of the slide bar (521). The first slide block (43) is also connected to telescopic rods (44) at both ends. The end of the telescopic rods (44) is connected to a second slide block (45), and the second slide block (45) is slidably disposed on the slide bar (521).

5. The physical simulation device for superimposed compression and tension stress fields according to claim 1, characterized in that, The bottom surface of the inner box (4) is provided with rubber (6) between the side panels (52).

6. The physical simulation device for superimposed compression and tension stress fields according to claim 5, characterized in that, The rubber sheet (6) is laid flat on the bottom surface of the inner box (4), and one end of it is fixed to the fixing plate (53), and the other end is fixed to the inner box (4) by adhesive. A wet sand layer (7) is laid on the top of the rubber sheet (6), and a dry sand layer (8) is laid on the top of the wet sand layer (7).

7. The physical simulation device for superimposed compression and tension stress fields according to claim 6, characterized in that, A glass bead layer (9) is laid between the rubber sheet (6) and the wet sand layer (7).

8. The physical simulation device for superimposed compression and tension stress fields according to claim 7, characterized in that, The thickness of the glass bead layer (9) is 0.2-0.5 cm, the thickness of the wet sand layer (7) is 2-3 cm, and the thickness of the dry sand layer (8) is 0.5-1 cm.

9. The physical simulation device for superimposed compression and tension stress fields according to claim 3, characterized in that, The bottom end of the movable plate (51) is provided with a protrusion (511), and a through hole is provided on the protrusion (511).

10. The physical simulation device for superimposed compression and tension stress fields according to claim 1, characterized in that, A spring is installed inside the groove (41).

11. An experimental method for a physical simulation device of superimposed compressive and tensile stress fields, characterized in that, Includes the following steps: S1: Fix the rubber sheet (6) on the experimental table, and push the movable plate (51) forward through the power device (1). The rubber sheet (6) remains stationary, so that the movable plate (51) moves a certain distance at a certain speed. S2: The top plane of the sand box is scanned by the scanner (4) after moving a certain distance. The structural evolution of the dry sand layer (8), wet sand layer (7) and glass bead layer (9) under the extrusion state is recorded by the camera (6) from the front of the sand box, so that the structural physical simulation can complete the extrusion experiment data collection. S3: After the physical simulation of the extrusion structure is completed, the sand box top plane is swept and filled with sand by the automatic sand distribution device (3). S4: Unfix the end of the rubber sheet (6) near the power device (1) to the experimental table, and fix the unfixed rubber sheet (6) on the movable plate (51). Pull the movable plate (51) backward through the power device (1) to generate tensile stress in the rubber sheet (6) and maximize the tensile distance at a certain speed. S5: After the top plane of the sand box is scanned by a scanner and moved a certain distance, the structural evolution state of the dry sand layer (8), wet sand layer (7) and glass bead layer (9) is recorded by a camera from the front of the sand box under tension, so that the structural physical simulation can complete the collection of tension experiment data. S6: After the physical simulation of the tension structure is completed, the sand box is filled with sand by the automatic sand distribution device (3) to complete one compression and tension experiment.

12. The experimental method of the physical simulation device for superimposed compression and tension stress fields according to claim 1, characterized in that, In steps S1 and S4, the moving speed is set to 0.02 to 0.08 mm / s, and the extrusion distance in step S1 is 6 to 10 cm.

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