An apparatus for preparing a simulated sample

Abstract

The disclosure provides a preparation device for simulating a sample, which comprises a constraint mechanism and a molding mechanism; the constraint mechanism comprises a constraint mold and a supporting bottom disc; the constraint mold has an internal space for constraining the molding mechanism, and the supporting bottom disc is arranged at one end of the constraint mold and supports a simulated sample in the constraint mold; the molding mechanism comprises a molding lining for preparing the simulated sample, and the molding lining can be accommodated in the internal space; the molding mechanism further comprises a fracture preparation mechanism which can be detachably fixed to the constraint mold and the side wall of the molding lining, and the fracture preparation mechanism is used for preparing a fracture in the simulated sample. The disclosure solves the technical problems of difficult molding and low precision of weak aggregate fracture sample, and is suitable for scientific test and research in the field of geotechnical engineering.

Description

Technical Field

[0001] This disclosure relates to the field of indoor testing technology in geotechnical engineering, and in particular to an apparatus for preparing simulated specimens. Background Technology

[0002] Similar material simulation testing is a key research method in geotechnical engineering. It involves mixing and consolidating materials such as sand, gravel, cement, calcium carbonate, and paraffin wax in specific proportions, and then preparing scaled-down specimens with similar physical and mechanical properties to the original rock for theoretical and technical research. This method offers significant advantages, including convenient specimen preparation, short testing cycles, low cost, and diverse test types, and is widely used in geological model inversion and standard specimen testing. Among various specimen types, the application of standard cylindrical specimens is particularly common: intact specimens can be used for testing basic material properties and optimizing stratigraphic mix proportions, while specimens with defects such as pre-existing cracks are suitable for specific target tests.

[0003] Currently, the preparation process for complete, similar, standard cylindrical specimens is relatively mature and widely used in practice. However, for specimens containing defects such as cracks, especially those prepared with weak materials such as sand and soil as aggregates, the forming technology still has significant shortcomings. Due to the properties of weak aggregates, sand and soil specimens themselves have poor mechanical properties, and the introduction of pre-fabricated cracks further weakens their overall strength, making the specimens extremely prone to breakage during preparation and making it difficult to guarantee the integrity of the forming. In addition, traditional methods for preparing complete specimens cannot accurately control the geometric characteristics of cracks, such as the dip angle and aperture, limiting their applicability in the study of the mechanical behavior of fractured rock masses.

[0004] It should be noted that the above description of the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of this invention. Summary of the Invention

[0005] In view of this, the purpose of this disclosure is to propose a device for preparing simulated specimens, which can solve to a certain extent or partially solve the technical problems of difficulty in forming defective specimens under weak aggregate conditions and low accuracy in restoring crack structures.

[0006] To achieve the above objectives, an exemplary embodiment of this disclosure provides a simulated sample preparation apparatus, including a constraint mechanism and a molding mechanism;

[0007] The constraint mechanism includes a constraint mold and a supporting chassis;

[0008] The constraint mold has an internal space for constraining the molding mechanism, and the supporting base is disposed at one end of the constraint mold and supports the simulated sample inside the constraint mold;

[0009] The molding mechanism includes a molding liner for preparing the simulated sample, the molding liner being accommodating the internal space;

[0010] The molding mechanism also includes a crack preparation mechanism that can be detachably fixed to the sidewalls of the constraint mold and the molding liner, the crack preparation mechanism being used to prepare cracks in the simulated sample.

[0011] Optionally, the crack preparation mechanism includes a positioning wedge and a molding tongue. The positioning wedge can be detachably fixed to the sidewalls of the constraint mold and the molding liner and includes a strip-shaped hole with a predetermined extension direction. One end of the molding tongue passes through the strip-shaped hole and through the constraint mold. The molding tongue passes through the constraint mold to form a crack in the simulated sample with a shape corresponding to the predetermined extension direction.

[0012] Optionally, the constraint mechanism further includes an indenter; the indenter is used to control the forming height of the simulated specimen and to apply axial pressure to the simulated specimen;

[0013] The indenter includes an indenter end cap and an indenter positioning column; the indenter positioning column can be inserted from the top opening of the constraint mold to apply axial pressure to the simulated sample.

[0014] Optionally, the supporting chassis has supporting chassis positioning posts for positioning and constraining the molding liner; the supporting chassis positioning posts can be inserted into the bottom opening of the molding liner.

[0015] Optionally, the constraint mold includes a symmetrical first constraint mold and a second constraint mold. Both the first constraint mold and the second constraint mold include a semi-cylindrical constraint part and a plate-shaped fixing part disposed on both sides of the constraint part. The first constraint mold and the second constraint mold are engaged to form the internal space between the two constraint parts. The plate-shaped fixing parts of the first constraint mold and the second constraint mold are correspondingly attached and can be fixed by a fixing component.

[0016] Optionally, the molding liner includes a symmetrical first molding liner and a second molding liner, both of which include a semi-cylindrical molding portion. The first molding liner and the second molding liner are mated to form a cylindrical molding space between the two molding portions.

[0017] The first constraint mold has a first opening;

[0018] A second opening is provided on the first lining at a position corresponding to the first opening;

[0019] The first opening and the second opening provide a fixed position for the positioning wedge and a channel for the shaped tongue to extend into the internal space.

[0020] Optionally, the first opening of the first constraint mold further includes fastening plate counters on both sides, and the fastening plate counters are provided with countersink fastening screw holes; the positioning wedge is provided with positioning wedge fastening screw holes, and the forming mechanism further includes fastening plates, the fastening plates including a first screw hole corresponding to the countersink fastening screw hole and a second screw hole corresponding to the positioning wedge fastening screw hole;

[0021] The fastening plate is connected to the positioning wedge and the fastening plate countersink respectively by fasteners passing through corresponding screw holes, and transmits pressure to the fastening plate countersink, so that the positioning wedge is pressed and fixed in the first opening and the second opening.

[0022] Optionally, there are multiple positioning wedges, and the predetermined extension direction of the strip hole on different positioning wedges is different. The molding tongue is matched with different positioning wedges to prepare cracks with different inclination angles in the simulated sample.

[0023] Optionally, the number of the positioning wedge and the shaping tongue are both multiple;

[0024] The lengths of the strip holes on the different positioning wedges are different, and the widths of the different molding tongues are different. The molding tongues of different widths are paired with positioning wedges having strip holes of corresponding lengths to prepare cracks of different lengths in the simulated specimen; and / or

[0025] The opening of the strip hole on the different positioning wedges is different, and the thickness of the different shaped tongues is different. The shaped tongues of different thicknesses are paired with the positioning wedges with strip holes of corresponding opening to prepare cracks with different openings in the simulated sample.

[0026] Optionally, the molding mechanism further includes a shearing testing mechanism; the shearing testing mechanism includes a cylindrical shearing liner and a gasket for performing a shearing test on the simulated specimen;

[0027] The inner and outer diameters of the sheared liner are the same as those of the molded liner, and positioning grooves are provided on the side walls of the top and bottom ends of the sheared liner; a gasket positioning block is provided on the outer side wall of the gasket, and the gasket positioning block can be embedded in the positioning groove to position the gasket.

[0028] The simulated specimen preparation apparatus provided in this embodiment includes a constraint mechanism and a molding mechanism. Through a modular and detachable design, the molding liner can be stably accommodated within the internal space of the constraint mold, and the bottom support is provided by the supporting base. This forms uniform lateral and axial constraints during the compaction process, effectively reducing the stress concentration and breakage risk of weak materials during compaction and demolding. At the same time, through the crack preparation mechanism that is detachably fixed to the mold and the side wall of the liner, cracks with preset geometric features can be implanted synchronously and accurately during the compaction process. This achieves high-precision and high-success-rate preparation of weak specimens with pre-made cracks while ensuring the integrity of the specimen, meeting the experimental needs for refined research on the mechanical response and failure mechanism of similar materials of fractured rock masses. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this disclosure or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of a simulated sample preparation apparatus provided in an embodiment of this disclosure;

[0031] Figure 2A A schematic diagram of the constraint mechanism provided in the embodiments of this disclosure;

[0032] Figure 2B A schematic diagram of the structure of the constraint mold provided in the embodiments of this disclosure;

[0033] Figure 2C A schematic diagram of the structure of the first constraint mold provided in an embodiment of this disclosure;

[0034] Figure 2D This is a schematic diagram of the structure of the second constraint mold provided in an embodiment of this disclosure;

[0035] Figure 2E This is a schematic diagram of the pressure head provided in an embodiment of the present disclosure;

[0036] Figure 2F This is a schematic diagram of the structure of the chassis support provided in an embodiment of this disclosure;

[0037] Figure 3A This is a schematic diagram of an exemplary positioning wedge provided in an embodiment of the present disclosure;

[0038] Figure 3B A schematic diagram of the structure of a strip hole with different tilt angles provided in the embodiments of this disclosure;

[0039] Figure 3C A schematic diagram of the dimensions of an exemplary strip hole provided in this disclosure embodiment;

[0040] Figure 3D This is a schematic diagram of the structure of the tongue provided in the embodiments of this disclosure;

[0041] Figure 3E This is a schematic diagram of the structure of the fastening plate provided in an embodiment of this disclosure;

[0042] Figure 3F This is a schematic diagram of the structure of the molding liner provided in the embodiments of this disclosure;

[0043] Figure 4A This is a schematic diagram of the shear liner provided in an embodiment of the present disclosure;

[0044] Figure 4B This is a schematic diagram of the structure of the gasket provided in an embodiment of the present disclosure;

[0045] Figure 4C This is a schematic diagram showing the state of the gasket provided in this embodiment after it is assembled onto the shear liner.

[0046] Explanation of reference numerals in the attached figures:

[0047] (1) Constraint mechanism: 1-1—Constraint mold, 1-2—Constraint mold fastening screw hole, 1-3—Fastening plate countersunk, 1-4—First opening, 1-5—Indenter end cap, 1-6—Indenter positioning column, 1-7—Supporting base, 1-8—Supporting base positioning column, 1-9—Countersunk fastening screw hole, 1-10—Plate-shaped fixing part;

[0048] (2) Molding mechanism: 2-1—positioning wedge, 2-2—strip hole, 2-3—positioning wedge fastening screw hole, 2-4—molding tongue, 2-5A—first molding liner, 2-5B—second molding liner, 2-6—second opening, 2-7—fastening plate;

[0049] (3) Shear test mechanism: 3-1—Shear liner, 3-2—Positioning groove, 3-3—Gasket, 3-4—Gasket positioning block. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this disclosure clearer, the principles and spirit of this disclosure will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are provided merely to enable those skilled in the art to better understand and implement this disclosure, and are not intended to limit the scope of this disclosure in any way. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of this disclosure to those skilled in the art.

[0051] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] As described in the background section, the complete sample preparation apparatus in the related technologies cannot meet the research needs of weak aggregate samples with pre-existing cracks in terms of molding control and accurate crack reduction.

[0053] The inventors of this disclosure have discovered that the reason why the related technology cannot meet the above-mentioned research needs is:

[0054] In related technologies, sample preparation devices are mainly designed for intact samples, lacking an effective control mechanism for the prefabrication process of fractured structures, and also failing to consider the vulnerability of weak materials during the molding process. Specifically, when loading and pressing weak aggregates, traditional devices cannot stably implant fractured prefabricated bodies with different inclination angles and geometric shapes inside the sample, making it difficult to accurately shape the fractured structure. At the same time, during demolding and sampling, weak samples containing fractures are prone to breakage along the fracture surface due to their low strength and significant stress concentration, resulting in the loss of sample integrity. Therefore, existing devices and methods cannot achieve high integrity preparation and geometric precision control of weak samples containing prefabricated fractures, and thus cannot meet the needs of refined research on mechanical response and failure mechanisms of similar materials of fractured rock masses.

[0055] To address the aforementioned problems, this disclosure provides an apparatus for preparing simulated samples.

[0056] refer to Figure 1 The present disclosure provides an apparatus for preparing a simulated sample, including a constraint mechanism 1000 (such as...). Figure 2A (as shown) and a molding mechanism. The constraint mechanism can be used to constrain the molding mechanism and the simulated specimen; the molding mechanism can be used to mold the simulated specimen, for example, to form a model specimen with a specific shape and to form cracks in the model specimen.

[0057] In some embodiments, such as Figure 2AAs shown, the constraint mechanism 1000 may further include a constraint mold 1-1 (see reference). Figure 2B (as shown) and supporting chassis 1-7. Among them,

[0058] The constraint mold 1-1 has an internal space for constraining the molding mechanism, and the supporting base 1-7 is disposed at one end of the constraint mold 1-1 and supports the simulated sample inside the constraint mold 1-1.

[0059] In some embodiments, the constraint mold 1-1 may further include a symmetrical first constraint mold 1-1A (e.g., Figure 2C (as shown) and the second constraint mold 1-1B (as shown) Figure 2D As shown, both the first constraint mold 1-1A and the second constraint mold 1-1B include a semi-cylindrical constraint portion and plate-shaped fixing portions 1-10 disposed on both sides of the constraint portion. The first constraint mold 1-1A and the second constraint mold 1-1B are mated to form the internal space between the two constraint portions. The plate-shaped fixing portions 1-10 of the first constraint mold 1-1A and the second constraint mold 1-1B are correspondingly attached and can be fixed by fixing components. Optionally, the plate-shaped fixing portion 1-10 is provided with constraint mold fastening screw holes 1-2, and the fixing component can be a fastening screw. In this way, by setting the constraint mold 1-1 into two open parts, the assembly and disassembly of the constraint mold can be more easily realized. In particular, after the simulated sample is prepared, the constraint mold can be opened by removing the fastening screws, and the simulated sample inside can be easily removed.

[0060] In some embodiments, such as Figure 2A and Figure 2E As shown, the constraint mechanism 1000 may further include a pressure head. The pressure head can be used to control the molding height of the simulated specimen and to apply axial pressure to the simulated specimen. Optionally,

[0061] like Figure 2E As shown, the pressure head may further include a pressure head end cap 1-5 and a pressure head positioning post 1-6, the pressure head positioning post 1-6 being able to open from the top of the constraint mold 1-1 (see reference). Figure 2B The top circular opening of the middle constraint mold 1-1 is inserted to apply axial pressure to the simulated specimen.

[0062] In this embodiment, the indenter positioning column 1-6 precisely limits the forming height of the simulated specimen by controlling the depth of its insertion into the top opening of the constraint mold 1-1, while simultaneously performing axial compaction during the preparation of the crack simulation specimen. The indenter of this device is the core component for controlling the overall height of the simulated specimen and imparting a predetermined similarity strength to the specimen.

[0063] In some embodiments, such as Figure 2F As shown, the supporting chassis 1-7 has features for positioning and constraining the molding liner (e.g., Figure 3F The supporting chassis positioning column 1-8 (as shown) can be inserted into the bottom opening of the molding liner to achieve positioning of the molding liner.

[0064] In this embodiment, the supporting chassis 1-7 serves as a stable base for the entire device, ensuring stability during the preparation of the simulated sample.

[0065] In this embodiment, the dual-eared, laterally constrained mold of the device is closed and fastened in the same position. One end is embedded in the positioning column of the supporting chassis, and the other end serves as the entry end for the loading, compaction, and shaping of the crack simulation sample preparation.

[0066] In some embodiments, the molding mechanism includes a molding liner for preparing the simulated specimen (see reference). Figure 3F As shown), the molding liner can be accommodated by the internal space of the constraint mold 1-1, so that the constraint mold can constrain the molding liner.

[0067] Furthermore, the molding mechanism may also include a crack preparation mechanism that can be detachably fixed to the sidewalls of the constraint mold 1-1 and the molding liner. This crack preparation mechanism is used to prepare cracks in the simulated sample. Thus, by using a crack preparation mechanism detachably fixed to the mold and the liner sidewalls, cracks with pre-defined geometric features can be simultaneously and precisely implanted during the compaction of the simulated sample. This achieves high-precision and high-success-rate preparation of simulated samples with pre-prepared cracks while ensuring sample integrity.

[0068] In some embodiments, the fracture preparation mechanism may further include a positioning wedge 2-1 (e.g., Figure 3A (as shown) and the shaping tongues 2-4 (as shown) Figure 3D (As shown). Reference Figure 1 As shown, the positioning wedge 2-1 can be detachably fixed to the sidewalls of the constraint mold 1-1 and the molding liner. Figure 3A As shown, the positioning wedge 2-1 includes a strip-shaped hole 2-2 with a predetermined extending direction. This strip-shaped hole 2-2 can be used for the forming tongue 2-4 to pass through and can define the tilting state of the forming tongue 2-4. (Reference) Figure 1As shown, one end of the molding tongue 2-4 can pass through the strip hole 2-2 and through the constraint mold 1-1. The molding tongue 2-4, passing through the constraint mold 1-1, forms a crack in the simulated sample with a shape corresponding to the predetermined extension direction of the strip hole 2-2. Thus, through the design of the combination of the strip hole 2-2 on the positioning wedge 2-1 and the molding tongue 2-4, the effect of forming a crack of the corresponding shape in the simulated sample can be achieved. The accuracy of the crack shape is guaranteed, meeting the experimental requirements for refined research on the mechanical response and failure mechanism of similar materials to fractured rock masses.

[0069] In some embodiments, such as Figure 3F As shown, the molding liner may further include a symmetrical first molding liner 2-5A and a second molding liner 2-5B. Both the first molding liner 2-5A and the second molding liner 2-5B include a semi-cylindrical molding part. The first molding liner 2-5A and the second molding liner 2-5B are engaged to form a cylindrical molding space between the two molding parts, for preparing a simulated sample with a cylindrical shape.

[0070] Furthermore, such as Figure 2C As shown, a first opening 1-4 can be provided on the first constraint mold 1-1A; correspondingly, as Figure 3F As shown, a second opening 2-6 is provided on the first molding liner 2-5A at a position corresponding to the first opening 1-4. Similarly, a first opening 1-4 can also be provided on the second constraint mold 1-1B; correspondingly, as Figure 3F As shown, a second opening 2-6 can also be provided on the second lining 2-5B at the position corresponding to the first opening 1-4.

[0071] refer to Figure 1 As shown, the first opening 1-4 and the second opening 2-6 provide the fixed position of the positioning wedge 2-1 and the channel for the molding tongue 2-4 to extend into the internal space. Thus, the molding tongue 2-4 can pass through the first opening 1-4 and the second opening 2-6 on one side of the preparation device and exit through the first opening 1-4 and the second opening 2-6 on the other side of the preparation device, thereby forming a through-crack in the simulated sample. Furthermore, the positioning wedge 2-1, fixed to the first opening 1-4 and the second opening 2-6, can be constrained by the mold and the molding liner, thus improving stability and ensuring accurate crack preparation.

[0072] In this embodiment, since both the constraint mold and the molding liner are symmetrical structures, the terms "first" and "second" are used only to distinguish the two parts and do not refer to any one of them.

[0073] In some embodiments, such as Figure 2C As shown, the first opening 1-4 of the first constraint mold 1-1A and / or the second constraint mold 1-1B further includes fastening plate countersunk 1-3 on both sides, and the fastening plate countersunk 1-3 is provided with countersunk fastening screw holes 1-9; the positioning wedge 2-1 is provided with positioning wedge fastening screw holes 2-3, and the forming mechanism further includes fastening plates 2-7 (such as...). Figure 3E As shown), the fastening plate 2-7 includes a first screw hole corresponding to the countersunk fastening screw hole 1-9 (for example, as shown). Figure 3E The two screw holes at the top center) and the second screw hole corresponding to the positioning wedge fastening screw holes 2-3 (e.g., as shown in the image). Figure 3E (The two screw holes at the bottom center). It can be understood that the two sides of the first opening can refer to the top and bottom sides or the left and right sides, as shown in the illustration, which shows the top and bottom sides.

[0074] For example, such as Figure 3E As shown, the fastening plate 2-7 is a plate-shaped pressure block with screw holes. Fasteners pass through the corresponding screw holes and are connected to the positioning wedge 2-1 and the fastening plate countersunk 1-3 respectively, transmitting pressure to the fastening plate countersunk 1-3, so that the positioning wedge 2-1 is pressed and fixed in the first opening 1-4 and the second opening 2-6, preventing it from shifting during the sample compaction process.

[0075] In some embodiments, the number of positioning wedges 2-1 is multiple. For example... Figure 3B The predetermined extension directions of the strip holes 2-2 on the different positioning wedges 2-1 are different, enabling variable control of the pre-fabricated crack inclination angle, thereby preparing crack specimens with different inclination angles. The molding tongue is paired with different positioning wedges to prepare cracks with different inclination angles in the simulated specimen.

[0076] In some embodiments, there are multiple positioning wedges 2-1 and multiple shaping tongues 2-4;

[0077] The length l of the strip hole 2-2 on different positioning wedges 2-1 is different, and the width a of different molding tongues 2-4 is different. Molding tongues 2-4 of different widths are paired with positioning wedges 2-1 having strip holes 2-2 of corresponding lengths to prepare cracks of different lengths in the simulated specimen; and / or

[0078] The opening w of the strip hole 2-2 on different positioning wedges 2-1 is different, and the thickness b of different shaped tongues 2-4 is different. The shaped tongues 2-4 of different thicknesses are paired with positioning wedges 2-1 with strip holes 2-2 of corresponding opening to prepare cracks with different openings in the simulated sample.

[0079] like Figure 3CAs shown, the length l of the strip hole 2-2 refers to the dimension of the strip hole 2-2 in its axial extension direction; as Figure 3D As shown, the width 'a' of the shaped tongue 2-4 refers to its dimension parallel to the length direction of the strip hole 2-2 when it is inserted into the strip hole 2-2; correspondingly, cracks of different lengths are prepared, and this length refers to the length formed by the simulated sample in its longitudinal direction.

[0080] Among them, such as Figure 3C As shown, the opening w of the strip hole refers to the dimension perpendicular to the axial extension direction of the strip hole 2-2; as Figure 3D As shown, the thickness b of the shaped tongue 2-4 refers to its dimension parallel to the opening direction of the strip hole 2-2 when it is inserted into the strip hole 2-2; correspondingly, cracks with different openings are prepared, and this opening refers to the length perpendicular to the longitudinal direction of the simulated sample.

[0081] In this embodiment, the present disclosure achieves the goal of prefabricating cracks with different inclination angles inside a similar simulated standard cylindrical sample by embedding prefabricated crack positioning wedges with different angles in a reserved embedding groove, in conjunction with crack positioning wedge-shaped tongue plates. Simultaneously, by prefabricating crack positioning wedges with different lengths and opening sizes of tongue-shaped holes (strip holes), the diversified goal of prefabricating cracks with different lengths and opening sizes inside a similar simulated standard cylindrical sample is further achieved without changing the main structure of the sample preparation device.

[0082] In some embodiments, the molding mechanism may further include a shear testing mechanism; the shear testing mechanism includes a cylindrical shear liner 3-1 (e.g., for performing shear tests on the simulated specimen) for shear testing. Figure 4A (as shown) and gasket 3-3 (as shown) Figure 4B (As shown); the inner and outer diameters of the sheared inner liner 3-1 are the same as those of the molded inner liner 2-5, and positioning grooves 3-2 are provided on the side walls of the top and bottom ends of the sheared inner liner 3-1; a gasket positioning block 3-4 is provided on the outer side wall of the gasket 3-3, and the gasket positioning block 3-4 can be embedded in the positioning groove to position the gasket 3-3.

[0083] In this embodiment, the longitudinal height of the shear test liner 3-1 is the same as the longitudinal height of the constraint mold 1-1.

[0084] Wherein, the depth h2 of the positioning groove 3-2 at the bottom of the shear test liner 3-1 (e.g. Figure 4A (As shown) is greater than the longitudinal height h4 of the embedded gasket 3-3 (e.g.) Figure 4C (as shown); the height h1 from the bottom end of the positioning groove 3-2 at the top of the shearing liner 3-1 to the bottom edge of the shearing liner 3-1 (as shown). Figure 4A(As shown) is less than the height h3 of the semicircular height of the platform of the 3-3 pad (e.g.) Figure 4C The sum of the height of the simulated specimen and the height of the shear test specimen (as shown) should be at least 5 mm less than the height of the simulated specimen. In order to ensure the effect of the shear test, sufficient axial deformation space should be reserved for the simulated specimen.

[0085] The gasket positioning block 3-4 serves to mark the position of the gasket 3-3. Specifically, as shown... Figure 4C As shown, the positioning block 3-4 on the gasket 3-3, through its cooperation with the positioning groove 3-2 on the shear liner 3-2 (the dotted line portion shown in the figure), fixes the position of the gasket 3-3 while ensuring that the high semicircle of the first gasket 3-3A and the low semicircle of the second gasket 3-3B are placed in a corresponding position. The high and low semicircles of the gaskets 3-3 are designed to allow for misaligned shearing of the simulated specimen during longitudinal compression in shear tests. The terms "first" and "second" in "first gasket 3-3" refer to two gaskets installed at both ends of the shear test liner and do not refer to any specific one of them.

[0086] In this embodiment, the present disclosure can not only prepare simulated specimens with cracks of different tilt angles, but also conduct shear tests on the prepared simulated specimens.

[0087] In actual shear tests, the shear pads need to be positioned to ensure the test results. However, it is not possible to directly create positioning grooves on the double-eared, laterally open constraint mold. Furthermore, according to the requirements of the International Organization for Standardization (ISO), the standard specimen size for cement compressive strength testing should be a cylinder with a diameter of 50 mm and a height of 100 mm. Therefore, to accommodate both simulated specimen preparation and shear testing, the inner diameter of the double-eared, laterally open constraint mold in this device is appropriately enlarged. This ensures that when conducting simulated specimen preparation, the inner diameter of the double-eared, laterally open constraint mold is larger than the inner diameter of the shear liner, thus making the diameter of the loading space for simulated specimen preparation conform to ISO standards.

[0088] For example, the inner diameter of the shearing liner 3-1 is 50 mm, and a positioning groove 3-2 is provided on the shearing liner 3-1 to position the gasket 3-3. Based on this, when carrying out the simulation sample preparation work, the inner diameter of the constraint mold 1-1 needs to be greater than 50 mm. Therefore, the molding liner 2-5 needs to be placed inside the constraint mold 1-1 so that the diameter of the loading space for the simulation sample preparation is 50 mm.

[0089] In this embodiment, the two ears of the device are laterally constrained and closed in the same position. One end can not only serve as the entry end for the loading, compaction, and shaping of the fracture simulation sample preparation, but also as the entry end for adding linings of different specifications to achieve diversified functions.

[0090] The preparation device disclosed herein can significantly enrich the application scenarios and operability of similar material simulation tests. It overcomes the core technical difficulties of preparing defect-simulation labeled cylindrical specimens using weak materials such as sand and soil as aggregates. It reduces the limitations of pre-made or original defect-constructed specimens on the test cycle, test range, and test feasibility. Small-scale similarity simulation tests based on weak materials such as sand and soil can be widely used, injecting new technical means and ideas into promoting scientific research progress in fields such as mining geology and geotechnical engineering.

[0091] This disclosure also provides a method for using an apparatus for preparing a simulated sample, comprising the following steps:

[0092] Before starting the preparation of the simulated specimen, the inclination angle, opening and length of the pre-made crack of the target simulated specimen are obtained, and the corresponding positioning wedge 2-1 and the molding tongue 2-4 are determined.

[0093] First, take the first constraint mold 1-1A, place a positioning wedge 2-1 of the selected size into the first opening 1-4, and fix it with two fastening pieces 2-7. Then, take the first molding liner 2-5A, and fit the second opening 2-6 onto the protruding part on the inner wall of the constraint mold 1-1 of the positioning wedge 2-1, so that the constraint mold 1-1 and the molding liner 2-5 fit tightly together.

[0094] Next, repeat the above steps to assemble the second constraint mold 1-1B, the second molding liner 2-5B, and the positioning wedge 2-1.

[0095] Then, place the support base 1-7 in the designated position, and place one end of the two sets of constraint molds 1-1, the molding liner 2-5 and the positioning wedge 2-1 that have been assembled on the support base positioning column 1-8 of the support base 1-7. Align and fasten the constraint mold fastening screw holes 1-2 and fix them with screws so that the support base positioning column 1-8 is completely embedded in the cylinder formed by the combination of the two sets of constraint molds 1-1, the molding liner 2-5 and the positioning wedge 2-1.

[0096] Finally, take the molding tongue 2-4 and insert it into the slot 2-2 on the positioning wedge 2-1, and then pass it out through the slot 2-2 on the opposite positioning wedge 2-1. Add material from the upper port of the device. After the predetermined amount of material has been added, use the pressure head to compact the material evenly until the pressure head positioning column 1-6 is completely embedded in the cylinder formed by the combination of the two sets of constraint molds 1-1, the molding liner 2-5 and the positioning wedge 2-1. The sample filling and preparation are now complete.

[0097] After a fixed period of consolidation, the prepared similar simulated standard cylindrical specimen is ready to be removed. First, the indenter is removed, and the molding tongue 2-4 is pulled out at a constant speed. The fastening screws at the fastening screw holes 1-2 of the constraint mold are removed. The two sets of constraint molds 1-1, molding liner 2-5 and positioning wedge 2-1 are separated. The prepared similar simulated standard cylindrical specimen is then removed, and the single specimen preparation process is completed.

[0098] When performing a shear test, after fixing the simulated specimen, the following steps should be taken:

[0099] First, remove the pressure head, and pull out the molding tongue 2-4 and molding liner 2-5 at a uniform speed. Place the shearing liner 3-1 into the constraint mold 1-1, keeping the fixture in a flat position at this time.

[0100] Next, take the first gasket 3-3A and embed its gasket positioning block 3-4 into the positioning groove 3-2 of the shear liner 2-5. Place the prepared similar simulated standard cylindrical sample from one end of the shear liner 2-5 so that the simulated sample contacts the semi-circular surface of the lower gasket 3-3 platform. Then, stand the fixture upright.

[0101] Then, take the second gasket 3-3B and embed its gasket positioning block 3-4 into the positioning groove 3-2 of the shear liner 2-5, so that the raised semicircle of the gasket 3-3 contacts the top surface of the simulated sample. It is particularly important to note that after both gaskets 3-3 are installed, the raised semicircle of the first gasket 3-3A and the lower semicircle of the second gasket 3-3B should be on the same semicircular side relative to each other; that is, the raised / lower semicircles of the first gasket 3-3A and the second gasket 3-3B should not be on the same semicircular side.

[0102] This disclosure, by setting up a shim with a high platform semicircle and a low platform semicircle and its positioning block, forms a preset spatial misalignment between the working surfaces of the upper and lower shims after the simulated sample is assembled, thereby transforming the traditional direct shear into a misaligned shear under controllable longitudinal compression, and realizing a composite stress state simulation that is closer to real geological conditions.

[0103] The simulated specimen preparation apparatus provided in this disclosure includes a constraint mechanism and a molding mechanism. Through modular design and a detachable connection structure, it achieves precise control over the preparation process of fracture simulated specimens. The apparatus, through the cooperation of a pre-angled slotted hole in a positioning wedge and an insertable molding tongue, can stably and accurately mold fracture structures with different angles and geometric shapes inside the specimen. Simultaneously, the constraint mold and the supporting base provide overall support and lateral constraint, effectively reducing stress concentration and the risk of breakage in weak materials during compaction and demolding. Thus, while ensuring specimen integrity, it achieves high-precision and high-success-rate preparation of weak specimens containing pre-fabricated fractures, meeting the experimental needs for refined research on the mechanical response and failure mechanisms of similar materials in fractured rock masses.

[0104] It should be noted that the above description describes some embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0105] Furthermore, although the operations of the methods of this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all of the operations shown must be performed to achieve the desired result. Rather, the steps depicted in the flowcharts may be executed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0106] The use of the verbs "including" and "contains" and their inflections in the application documents does not preclude the existence of elements or steps other than those described in the application documents. The article "a" or "one" preceding an element does not preclude the existence of multiple such elements.

[0107] While the spirit and principles of this disclosure have been described with reference to several specific embodiments, it should be understood that this disclosure is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for convenience of expression. This disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the appended claims is to be interpreted in the broadest sense, thereby encompassing all such modifications and equivalent structures and functions.

Claims

1. An apparatus for preparing a simulated sample, characterized in that, This includes constraint mechanisms and molding mechanisms; The constraint mechanism includes a constraint mold and a supporting chassis; The constraint mold has an internal space for constraining the molding mechanism, and the supporting base is disposed at one end of the constraint mold and supports the simulated sample inside the constraint mold; The molding mechanism includes a molding liner for preparing the simulated sample, the molding liner being accommodating the internal space; a first opening is provided on the constraint mold; A second opening is provided on the lining material at a position corresponding to the first opening; The molding mechanism also includes a crack preparation mechanism that can be detachably fixed to the sidewalls of the constraint mold and the molding liner, the crack preparation mechanism being used to prepare cracks in the simulated sample; The crack preparation mechanism includes a positioning wedge and a molding tongue. The positioning wedge can be detachably fixed to the sidewalls of the constraint mold and the molding liner and includes a strip hole with a predetermined extension direction. One end of the molding tongue passes through the strip hole and through the constraint mold. The molding tongue passes through the constraint mold to form a crack in the simulated sample with a shape corresponding to the predetermined extension direction. The positioning wedge is fixed to the first opening and the second opening.

2. The apparatus according to claim 1, characterized in that, The constraint mechanism also includes a pressure head; the pressure head is used to control the forming height of the simulated specimen and to apply axial pressure to the simulated specimen. The indenter includes an indenter end cap and an indenter positioning column; the indenter positioning column can be inserted from the top opening of the constraint mold to apply axial pressure to the simulated sample.

3. The apparatus according to claim 1, characterized in that, The supporting chassis has a supporting chassis positioning column for positioning and constraining the molding liner; the supporting chassis positioning column can be inserted into the bottom opening of the molding liner.

4. The apparatus according to claim 1, characterized in that, The constraint mold includes a symmetrical first constraint mold and a second constraint mold. Both the first constraint mold and the second constraint mold include a semi-cylindrical constraint part and a plate-shaped fixing part disposed on both sides of the constraint part. The first constraint mold and the second constraint mold are engaged to form the internal space between the two constraint parts. The plate-shaped fixing parts of the first constraint mold and the second constraint mold are correspondingly attached and can be fixed by a fixing component.

5. The apparatus according to claim 4, characterized in that, The molding liner includes a symmetrical first molding liner and a second molding liner. Both the first molding liner and the second molding liner include a semi-cylindrical molding part. The first molding liner and the second molding liner are mated to form a cylindrical molding space between the two molding parts. The first constraint mold has a first opening; A second opening is provided on the first lining at a position corresponding to the first opening; The first opening and the second opening provide a fixed position for the positioning wedge and a channel for the shaped tongue to extend into the internal space.

6. The apparatus according to claim 5, characterized in that, The first opening of the first constraint mold also includes fastening plate counters on both sides, and the fastening plate counters are provided with countersink fastening screw holes; the positioning wedge is provided with positioning wedge fastening screw holes, and the forming mechanism also includes fastening plates, the fastening plates including a first screw hole corresponding to the countersink fastening screw hole and a second screw hole corresponding to the positioning wedge fastening screw hole; The fastening plate is connected to the positioning wedge and the fastening plate countersink respectively by fasteners passing through corresponding screw holes, and transmits pressure to the fastening plate countersink, so that the positioning wedge is pressed and fixed in the first opening and the second opening.

7. The apparatus according to claim 1, characterized in that, The number of positioning wedges is multiple, and the predetermined extension direction of the strip hole on the different positioning wedges is different. The molding tongue is matched with different positioning wedges to prepare cracks with different inclination angles in the simulated sample.

8. The apparatus according to claim 1, characterized in that, The number of the positioning wedges and the shaping tongues are both multiple; The lengths of the strip holes on the different positioning wedges are different, and the widths of the different molding tongues are different. The molding tongues of different widths are paired with positioning wedges having strip holes of corresponding lengths to prepare cracks of different lengths in the simulated specimen; and / or The opening of the strip hole on the different positioning wedges is different, and the thickness of the different shaped tongues is different. The shaped tongues of different thicknesses are paired with the positioning wedges with strip holes of corresponding opening to prepare cracks with different openings in the simulated sample.

9. The apparatus according to claim 1, characterized in that, The molding mechanism also includes a shearing test mechanism; the shearing test mechanism includes a cylindrical shearing liner and a gasket for performing shear tests on the simulated specimen. The inner and outer diameters of the sheared liner are the same as those of the molded liner, and positioning grooves are provided on the side walls of the top and bottom ends of the sheared liner; a gasket positioning block is provided on the outer side wall of the gasket, and the gasket positioning block can be embedded in the positioning groove to position the gasket.

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