A triaxial shear test fixture and a seepage test device comprising the same

Abstract

The application discloses a triaxial shearing test clamp and a percolation test device comprising the same. The clamp comprises shearing boxes and limiting mechanisms. The number of the shearing boxes is two, and the shearing boxes are provided with grooves. The grooves of the two shearing boxes form a space for accommodating a rock sample. The limiting mechanisms are arranged in one-to-one correspondence with the shearing boxes. The limiting mechanism comprises a fixing seat, a push rod and a pressing plate. The number of the push rods is at least two. The push rods are in sliding connection with the fixing seat. The pressing plate is connected with the end of the push rod. The fixing seat is in abutment with the side wall of the groove. The pressing plate is in abutment with the rock sample. The two shearing boxes can be moved in a staggered manner. The sliding direction of the push rod is coaxially arranged with the moving direction of the shearing box. Through the extension and retraction of the push rod in the limiting mechanism, the pressing plate and the side wall of the groove can jointly clamp and fix the rock sample. This makes the test clamp be able to adapt to rock samples of different sizes, and also can eliminate the gap between the rock sample and the side wall of the shearing box groove.

Description

Technical Field

[0001] This invention relates to the field of rock mechanics experimental technology, and in particular to a triaxial shear test fixture and a seepage test apparatus including the fixture. Background Technology

[0002] In rock mechanics experimental research and deep engineering stability assessment, it is crucial to accurately obtain rock shear parameters under true triaxial stress state. These parameters can reflect the structural changes of rocks under confining pressure, seepage, and complex shear forces in deep environments, thereby providing data support for the development of deep underground resources and ensuring the safety and efficiency of the development process.

[0003] However, existing rock shear test fixtures generally suffer from poor dimensional compatibility and insufficient clamping accuracy. On the one hand, due to the fixed structural design, traditional fixtures are difficult to adapt to rock specimens of different specifications, resulting in low experimental flexibility and high costs. On the other hand, since millimeter-level geometric deviations are unavoidable during the processing of rock specimens, traditional mechanical fixtures cannot compensate for the gap between the specimen and the indenter. Moreover, the fixture may not be completely in contact with the rock specimen at the beginning of loading, which can easily lead to false displacement or stress concentration at the beginning of loading, seriously interfering with the authenticity of the test results.

[0004] Therefore, a fixture that can adapt to rock specimens of different sizes is needed to improve the versatility of the testing device; in addition, it is also needed to reduce spurious displacements during the loading process to improve the accuracy of the test results. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, this application proposes a triaxial shear test fixture capable of clamping rock specimens of different sizes and reducing spurious displacements during loading.

[0006] This application also proposes a seepage test apparatus having the above-mentioned triaxial shear test fixture.

[0007] The triaxial shear test fixture according to a first aspect embodiment of this application includes: There are two shear boxes, each with a groove, and the grooves of the two shear boxes form a space for accommodating the rock specimen. The limiting mechanism has two components, and each limiting mechanism is configured to correspond one-to-one with the shearing box. Each limiting mechanism includes a fixed base, a push rod, and a pressing plate. There are at least two push rods. The push rods are slidably connected to the fixed base. The pressing plate is connected to the end of the push rod. The fixed base abuts against the side wall of the groove. The pressing plate abuts against the rock specimen. The two shear boxes are able to move out of alignment with each other, and the sliding direction of the push rod is coaxial with the moving direction of the shear box.

[0008] The triaxial shear test fixture according to the embodiments of this application has at least the following beneficial effects: by extending and retracting the push rod in the limiting mechanism, the extrusion plate and the side wall of the groove can jointly clamp and fix the rock specimen, which makes the test fixture adaptable to rock specimens of different sizes, and can also eliminate the gap between the rock specimen and the side wall of the shear box groove, thus avoiding false displacement.

[0009] According to some embodiments of this application, the shear box includes a first shear box and a second shear box, wherein the first shear box moves along a first direction and the second shear box moves along a second direction.

[0010] According to some embodiments of this application, in the first shear box, the limiting mechanism drives the rock specimen to fit tightly against the first sidewall of the groove; during the movement of the first shear box, the first sidewall directly applies a force to the rock specimen.

[0011] According to some embodiments of this application, in the second shear box, the limiting mechanism drives the rock specimen to fit tightly against the second sidewall of the groove; during the movement of the second shear box, the second sidewall directly applies a force to the rock specimen.

[0012] According to some embodiments of this application, the projection of the first sidewall along the first direction does not coincide with the projection of the second sidewall along the second direction.

[0013] According to some embodiments of this application, the fixed base is provided with a hydraulic pipe, the push rod is slidably connected to the hydraulic pipe, and the space enclosed by the hydraulic pipe and the push rod is used to fill hydraulic oil.

[0014] According to some embodiments of this application, the triaxial shear test fixture further includes a hydraulic pump, which is connected to the hydraulic pipe via a pipeline, and is used to inject hydraulic oil into the space enclosed by the hydraulic pipe and the push rod.

[0015] According to some embodiments of this application, the fixed seats in both of the limiting mechanisms are connected to the hydraulic pump through the pipes.

[0016] The seepage test apparatus according to a second aspect of this application includes the triaxial shear test fixture described above.

[0017] The working method according to the third aspect of this application, which is based on the above-described triaxial shear test fixture, includes the following steps: The rock specimen was placed in the space enclosed by the two shear boxes; The limiting mechanism is activated, causing the extrusion plate to fit tightly against the surface of the rock specimen; The extrusion plate and the sidewall of the groove together clamp the rock specimen, subjecting the rock specimen to a preload force; The two shear boxes move in a staggered manner to apply shear force to the rock specimen.

[0018] The working method according to the embodiments of this application has at least the following beneficial effects: by using a limiting mechanism to push the rock specimen towards the side wall of the shear box groove, the random movement of the rock specimen within the shear box is avoided, thereby improving the accuracy of the test results.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] The accompanying drawings are used to provide a further understanding of the technical solutions disclosed in this application and form part of the specification. They are used together with the embodiments disclosed in this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions disclosed in this application.

[0021] Figure 1 This is a schematic diagram of the structure of the triaxial shear test fixture according to the first aspect of this application; Figure 2 This is a schematic diagram of the loading of the first shear box and the second shear box in the triaxial shear test fixture of the first aspect embodiment of this application; Figure 3 This is a schematic diagram of the rock specimen held by the triaxial shear test fixture according to the first aspect of this application.

[0022] Reference numerals: 100-shear box, 110-first shear box, 111-first side wall, 120-second shear box, 121-second side wall, 200-limiting mechanism, 210-fixed seat, 211-hydraulic pipe, 220-push rod, 230-extrusion plate, 300-hydraulic pump, 310-valve, 400-rock specimen, 410-sealing material. Detailed Implementation

[0023] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0024] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0026] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0027] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] In rock mechanics experimental research and deep engineering stability assessment, it is crucial to accurately obtain rock shear parameters under true triaxial stress state. These parameters can reflect the structural changes of rocks under confining pressure, seepage, and complex shear forces in deep environments, thereby providing data support for the development of deep underground resources and ensuring the safety and efficiency of the development process.

[0029] However, existing rock shear test fixtures generally suffer from poor dimensional compatibility and insufficient clamping accuracy. On the one hand, due to the fixed structural design, traditional fixtures are difficult to adapt to rock specimens of different specifications, resulting in low experimental flexibility and high costs. On the other hand, since millimeter-level geometric deviations are unavoidable during the processing of rock specimens, traditional mechanical fixtures cannot compensate for the gap between the specimen and the indenter. Moreover, the fixture may not be completely in contact with the rock specimen at the beginning of loading, which can easily lead to false displacement or stress concentration at the beginning of loading, seriously interfering with the authenticity of the test results.

[0030] Therefore, a fixture that can adapt to rock specimens of different sizes is needed to improve the versatility of the testing device; in addition, it is also needed to reduce spurious displacements during the loading process to improve the accuracy of the test results.

[0031] In response, this application proposes a triaxial shear test fixture. By extending and retracting the push rod in the limiting mechanism, the extrusion plate and the side wall of the groove can jointly clamp and fix the rock specimen. This allows the test fixture to be adapted to rock specimens of different sizes and can also eliminate the gap between the rock specimen and the side wall of the shear box groove, thus avoiding false displacement.

[0032] In addition, this application also proposes a seepage test device including the above-mentioned triaxial shear test fixture, and proposes a working method for the above-mentioned triaxial shear test fixture. The working method uses a limiting mechanism to push the rock specimen against the side wall of the shear box groove, thereby avoiding the random movement of the rock specimen in the shear box and improving the accuracy of the test results.

[0033] In this application, false displacement refers to invalid displacement before the shear box comes into contact with the rock specimen.

[0034] Reference Figure 1 and Figure 2 The triaxial shear test fixture in the first aspect embodiment of this application includes a shear box 100 and a limiting mechanism 200. The shear box 100 applies shear force to the rock specimen 400 to simulate complex stress conditions in deep rock strata. The limiting mechanism 200 tightly fixes the rock specimen 400 to the side wall of the shear box 100, thereby eliminating the gap between the rock specimen 400 and the side wall of the shear box 100, and preventing false displacement of the shear box 100 at the start of the test due to insufficient contact with the rock specimen 400, which would affect the test results.

[0035] Specifically, there are two shear boxes 100, each with a groove. The grooves of the two shear boxes 100 are arranged opposite each other, thus forming a space between the two grooves for accommodating the rock specimen 400. There are also two limiting mechanisms 200, each corresponding to one of the shear boxes 100. Each limiting mechanism 200 includes a fixed base 210, a push rod 220, and a pressing plate 230. The push rod 220 is slidably connected to the fixed base 210, and the pressing plate 230 is connected to the end of the push rod 220, so that the pressing plate 230 can be displaced under the push of the push rod 220. The fixed base 210 abuts against the side wall of the groove, and the pressing plate 230 abuts against the rock specimen 400, so that the pressing plate 230 can contact the rock specimen 400 and transmit force, stably confining the rock specimen 400 within the groove of the shear box 100.

[0036] The push rod 220 has at least two components, and the specific number can be increased or decreased according to actual needs. Increasing the number of push rods 220 can make the force exerted by the limiting mechanism 200 on the rock specimen 400 more uniform, thus avoiding damage to the rock specimen 400 due to uneven force and affecting the test results.

[0037] In this embodiment, the two shear boxes 100 can move out of alignment with each other, so that the rock specimen 400 is subjected to opposite forces from the two shear boxes 100, and the forces in the two directions are not coaxial, thus producing a shearing effect. The sliding direction of the push rod 220 is coaxial with the moving direction of the shear box 100, so that the rock specimen 400 will not have false displacement in the moving direction of the shear box 100.

[0038] Further, the clipping box 100 includes a first clipping box 110 and a second clipping box 120. The first clipping box 110 is along a first direction (refer to...). Figure 2 The second shear box 120 moves along the second direction (refer to x1 direction) and moves along the second direction (refer to x1 direction). Figure 2 Move in the x2 direction.

[0039] In some embodiments, when the shear box 100 moves in a misaligned manner, the limiting mechanism 200 in each shear box 100 bears the reverse force from the rock specimen 400. In this embodiment, when the shear box 100 moves in a misaligned manner, the sidewall of the groove in each shear box 100 bears the reverse force from the rock specimen 400. This is to avoid damage to the limiting mechanism 200 during the test and to prevent the limiting mechanism 200 from absorbing part of the force and affecting the test results.

[0040] Reference Figure 2 In the first shear box 110, the limiting mechanism 200 drives the rock specimen 400 to fit tightly against the first sidewall 111 of the groove. During the movement of the first shear box 110, the first sidewall 111 directly applies a force to the rock specimen 400, thereby the first sidewall 111 of the groove directly bears the reverse force from the rock specimen 400.

[0041] In the second shear box 120, the limiting mechanism 200 drives the rock specimen 400 to press tightly against the second sidewall 121 of the groove, and the second sidewall 121 directly applies force to the rock specimen 400. During the movement of the second shear box 120, the second sidewall 121 directly applies force to the rock specimen 400, so that the second sidewall 121 of the groove directly bears the reverse force from the rock specimen 400.

[0042] Furthermore, the projection of the first sidewall 111 along the first direction does not coincide with the projection of the second sidewall 121 along the second direction, which causes the rock specimen 400 to be subjected to forces of different axes and opposite directions, resulting in a shearing effect.

[0043] Furthermore, the driving method for the limiting mechanism 200 can be a hydraulic telescopic mechanism, a pneumatic telescopic mechanism, or an electric telescopic mechanism to generate driving force. This embodiment uses a hydraulic drive method. The fixed base 210 is equipped with a hydraulic pipe 211, and the push rod 220 is slidably connected to the hydraulic pipe 211. The space enclosed by the hydraulic pipe 211 and the push rod 220 is used to fill hydraulic oil. When hydraulic oil is injected into the space enclosed by the hydraulic pipe 211 and the push rod 220, the push rod 220 can be pushed out, thereby driving the extrusion plate 230 to move.

[0044] Furthermore, the triaxial shear test fixture also includes a hydraulic pump 300, which is connected to a hydraulic pipe 211 via a pipeline. The hydraulic pump 300 is used to inject hydraulic oil into the space enclosed by the hydraulic pipe 211 and the push rod 220. It is worth noting that the fixed seats 210 in both limiting mechanisms 200 are connected to the hydraulic pump 300 via pipelines, and valves 310 are installed on the pipelines to control the output hydraulic oil flow rate.

[0045] The seepage test apparatus in the second aspect of this application includes the aforementioned triaxial shear test fixture, which is used for deep rock strata seepage simulation tests and shear mechanics studies.

[0046] The working method in the third aspect embodiment of this application, based on the above-mentioned triaxial shear test fixture, includes the following steps: S100. Place the rock specimen 400 into the space enclosed by the two shear boxes 100; S200. Activate the limiting mechanism 200 so that the extrusion plate 230 fits tightly against the surface of the rock specimen 400; S300. The extrusion plate 230 and the side wall of the groove together clamp the rock specimen 400, so that the rock specimen 400 is subjected to pre-tightening force, and the rock specimen 400 is prevented from moving freely in the shear box 100. S400. The two shear boxes 100 move out of position relative to each other, causing the rock specimen 400 to be subjected to shear force.

[0047] Before placing the rock specimen 400, the push rod 220 in the limiting mechanism 200 should be controlled to retract to make enough space to place the rock specimen 400.

[0048] Rock specimen 400 can be a monolithic rock sample or a split rock sample. (Refer to...) Figure 3 Two jointed rock masses can be spliced ​​together, and a sealing material 410 (polyurethane-carbon nanotube sealing material is used in this embodiment) can be applied to the joint surfaces of the two masses to form a sealing coating. A shear test is then conducted to simulate a multi-field coupled shear flow test.

[0049] After the rock specimen 400 is loaded and clamped by the limiting mechanism 200, the entire triaxial shear test fixture is placed into the seepage test device. The servo system drives the dissimilar hydraulic actuators to move, causing the two shear boxes 100 to move in a staggered manner. The seepage test device is used to drive the fluid to flow along the joint surface.

[0050] The mutual offset movement of the two shear boxes 100 means that the first shear box 110 moves along the first direction and the second shear box 120 moves along the second direction.

[0051] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A triaxial shear test fixture, characterized in that, include: There are two shear boxes, each with a groove, and the grooves of the two shear boxes form a space for accommodating the rock specimen. The limiting mechanism has two components, and each limiting mechanism is configured to correspond one-to-one with the shearing box. Each limiting mechanism includes a fixed base, a push rod, and a pressing plate. There are at least two push rods. The push rods are slidably connected to the fixed base. The pressing plate is connected to the end of the push rod. The fixed base abuts against the side wall of the groove. The pressing plate abuts against the rock specimen. The two shear boxes are able to move out of alignment with each other, and the sliding direction of the push rod is coaxial with the moving direction of the shear box.

2. The triaxial shear test fixture according to claim 1, characterized in that: The shear box includes a first shear box and a second shear box, the first shear box moves along a first direction, and the second shear box moves along a second direction.

3. The triaxial shear test fixture according to claim 2, characterized in that: In the first shear box, the limiting mechanism drives the rock specimen to fit tightly against the first sidewall of the groove; during the movement of the first shear box, the first sidewall directly applies a force to the rock specimen.

4. The triaxial shear test fixture according to claim 3, characterized in that: In the second shear box, the limiting mechanism drives the rock specimen to fit tightly against the second sidewall of the groove; during the movement of the second shear box, the second sidewall directly applies a force to the rock specimen.

5. The triaxial shear test fixture according to claim 4, characterized in that: The projection of the first sidewall along the first direction does not coincide with the projection of the second sidewall along the second direction.

6. The triaxial shear test fixture according to claim 1, characterized in that: The fixed base is provided with a hydraulic pipe, and the push rod is slidably connected to the hydraulic pipe. The space enclosed by the hydraulic pipe and the push rod is used to fill hydraulic oil.

7. The triaxial shear test fixture according to claim 6, characterized in that: The triaxial shear test fixture also includes a hydraulic pump, which is connected to the hydraulic pipe via a pipeline. The hydraulic pump is used to inject hydraulic oil into the space enclosed by the hydraulic pipe and the push rod.

8. The triaxial shear test fixture according to claim 7, characterized in that: The fixed seats in both of the limiting mechanisms are connected to the hydraulic pump through the pipes.

9. A seepage test apparatus, characterized in that, Includes the triaxial shear test fixture as described in any one of claims 1 to 8.

10. A method for operating a triaxial shear test fixture based on any one of claims 1 to 8, characterized in that, include: The rock specimen was placed in the space enclosed by the two shear boxes; The limiting mechanism is activated, causing the extrusion plate to fit tightly against the surface of the rock specimen; The extrusion plate and the sidewall of the groove together clamp the rock specimen, subjecting the rock specimen to a preload force; The two shear boxes move in a staggered manner to apply shear force to the rock specimen.

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