A method for preparing a porous rock sample

Abstract

The present application relates to the field of rock mechanics test research, disclose a kind of preparation method of rock sample containing hole, comprising the following steps: S1: the inner wall of base and forming cylinder is all daubed release agent;S2: forming cylinder is installed on base;S3: install several forming mechanisms on forming cylinder, and daub release agent on forming mechanism;S4: configuration slurry, slurry is poured into forming cylinder and is vibrated and is formed;S5: curing sample;S6: disassemble forming mechanism and forming cylinder, and the sample is taken out.The technical scheme of the present application prepares the sample size consistent, good homogeneity, can be taken out from the inside of sample forming mechanism, so that forming mechanism will not affect the mechanical properties of sample, reduces test error.

Description

Technical Field

[0001] This invention relates to the field of rock mechanics experimental research, specifically to a method for preparing porous rock samples. Background Technology

[0002] In recent years, with the needs of mineral resource exploration and development, energy development, transportation engineering, urban construction and underground space development, the scale of rock engineering has become larger and larger, and the rock mechanics problems involved have become more and more complex.

[0003] Mining voids formed by human activities, excavated chambers, and karst caves formed by natural erosion all severely damage the integrity of rock masses, resulting in cavities within the rock mass. These cavities are generally large in size, vary in shape, and pose a high degree of danger. Engineering construction around rock masses with such defects carries the risk of engineering instability. In order to effectively evaluate the stability of rock masses with cavities, it is necessary to conduct mechanical testing on rock samples with cavities to effectively reveal the mechanical deformation characteristics and failure patterns of rocks with cavities.

[0004] Currently, the preparation of porous rock specimens remains a challenge and a bottleneck hindering research progress in this area. Previous studies have explored methods for creating fractures in rocks, but there is limited information on preparing specimens with porous defects. While surface fractures in rock specimens can be cut using a cutting machine, internal pores cannot be fabricated. For internal pores, plastic or aluminum spheres are typically used to simulate them. However, once the specimen is prepared, these spheres cannot be removed, and they tend to form a "skeleton," affecting the specimen's mechanical properties and leading to larger experimental errors. Summary of the Invention

[0005] The present invention aims to provide a method for preparing porous rock samples to reduce experimental errors.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a porous rock sample, comprising the following steps:

[0007] S1: Apply release agent to both the base and the inner wall of the molding cylinder;

[0008] S2: Install the forming cylinder onto the base;

[0009] S3: Install several molding mechanisms on the molding cylinder and apply a release agent to the molding mechanisms;

[0010] S4: Prepare the slurry, pour the slurry into the molding cylinder and vibrate to form the shape;

[0011] S5: Curing test sample;

[0012] S6: Disassemble the molding mechanism and molding cylinder, and remove the sample.

[0013] The beneficial effects of this scheme are as follows: When preparing porous rock samples, since several forming mechanisms are installed on the forming cylinder, several pore structures can be created inside the sample. After the porous rock sample is prepared, the forming mechanisms can be removed from the sample, so that the forming mechanisms will not affect the mechanical properties of the sample and reduce experimental errors. Especially when conducting parallel experimental studies, since the samples prepared by this scheme are of consistent size and have good homogeneity, the creation of pore defects will not disturb the internal structure of the porous rock sample, thus further reducing experimental errors.

[0014] This technical solution consists of a base, a forming cylinder, and a forming mechanism. Therefore, the structure of the sample preparation device for cavitary rock materials provided by this technical solution is relatively simple and easy to mass-produce.

[0015] Because this technical solution has several forming mechanisms, it can simultaneously manufacture multiple complex hole defects in the same forming cylinder. In particular, it can significantly reduce test errors, especially for the prefabrication of large-size cross-sectional hole defects and high-pressure, high-strength specimens.

[0016] This technical solution has the advantages of simple operation, high sample preparation efficiency, and low sample preparation cost.

[0017] Furthermore, the forming cylinder in S2 is provided with several forming holes, the shape of which is any one or more combinations of circles, squares, prisms and polygons, and the forming mechanism matches the forming holes.

[0018] The beneficial effects of this solution are: due to the setting of the forming hole, the forming mechanism is easy to install and remove, thus facilitating the creation of holes inside the sample.

[0019] Because this technical solution has several forming holes on the forming cylinder, the installation position of the forming mechanism can be determined according to actual needs when installing the forming mechanism. This allows the technical solution to produce holes at different positions and tilt angles to meet the needs of different tests.

[0020] Since the shape of the hole can be any combination of one or more of the following: circular, square, prismatic, and polygonal, this technical solution allows for the production of samples with different shaped hole defects by changing different forming cylinders and forming mechanisms.

[0021] Furthermore, the forming cylinder in S2 includes several arc-shaped connecting blocks. The forming cylinder is a cylindrical structure formed by several arc-shaped connecting blocks, and the forming holes are distributed on the arc-shaped connecting blocks.

[0022] The beneficial effects of this solution are as follows: Since the molding cylinder is a cylindrical structure formed by several arc-shaped connecting blocks, it is easy to demold the molding cylinder during demolding, thus improving the efficiency of sample preparation.

[0023] Furthermore, the forming cylinder in S2 is detachably connected with a hoop.

[0024] The beneficial effects of this scheme are as follows: If the ring is not set, the molding cylinder may deform during the casting process, which will change the shape of the cast sample and the morphology of the holes, resulting in larger test errors when conducting parallel tests. The setting of the ring can improve the stability of the molding cylinder.

[0025] Furthermore, each molding mechanism in S3 includes a molding tube and two rotating units. The molding tube includes a first connecting part and a second connecting part, which are slidably and detachably connected to the second connecting part. Each rotating unit includes a positioning seat, a mounting seat, and a handle. The handle passes through the positioning seat and is detachably connected to the mounting seat. A universal ball is mounted on the mounting seat, and the end of the molding tube is rotatably and detachably connected to the universal ball.

[0026] The beneficial effects of this scheme are as follows: In use, first determine the number and location of the molding mechanism according to actual needs. Then connect the first and second connecting parts, seal any remaining unused molding holes, and proceed with casting and vibration molding. After the sample solidifies, remove the handle, then remove the positioning seat from the molding cylinder, and finally remove the molding cylinder from the base. Finally, pull the mounting base and molding tube out of the sample. Because the first and second connecting parts are slidably and detachably connected, they can separate during the process of pulling the mounting base and molding tube out of the sample. This facilitates the removal of the molding tube from the sample, preventing it from remaining inside and increasing experimental error.

[0027] Since the molding tube is composed of a first connecting part and a second connecting part, and the first connecting part and the second connecting part are slidably and detachably connected, the length of the molding tube can be adjusted according to the actual situation, which is convenient for making hole defects of different heights and tilt angles. At the same time, the first connecting part and the second connecting part can be separated during demolding, which makes it easy to remove the molding tube from the sample, improves the demolding efficiency, and also prevents the molding tube from being left inside the sample, causing the test error to be too large.

[0028] Because the first connecting part and the second connecting part are slidably and detachably connected, when creating interconnected hole defects in the same plane, two molding mechanisms are used. One molding mechanism is first installed on the molding cylinder, and then the first connecting part of the other molding mechanism is placed against the installed molding tube. The second connecting part of the other molding mechanism is placed against the appropriate position on the installed molding tube, and then casting is performed. In this way, interconnected hole defects in the same plane can be created. Therefore, the molding tube is slidably and detachably connected by the first connecting part and the second connecting part, which not only allows for adjustment of the length of the molding tube, but also allows for the creation of interconnected hole defects in the same plane.

[0029] Due to the universal ball joint, this technical solution allows for adjustment of the deflection angle of the forming tube by rotating the mounting base via the handle, making it suitable for manufacturing hole defects with different deflection angles.

[0030] Furthermore, a retaining ring is provided on the handle between the positioning seat and the mounting seat.

[0031] The beneficial effects of this solution are as follows: due to the setting of the retaining ring, this technical solution can prevent the mounting base from rubbing against the inner wall of the forming cylinder during rotation, thereby preventing wear of the forming cylinder and extending the service life of the forming cylinder.

[0032] Furthermore, two positioning beads are symmetrically installed on the omnidirectional ball, and the end of the forming tube is rotatably and detachably connected to the positioning beads.

[0033] The beneficial effects of this solution are: the placement of the positioning beads facilitates the installation and disassembly of the forming tube.

[0034] Furthermore, in S3, the molding mechanism is installed as follows: the free ends of both the first connecting part and the second connecting part pass through different molding holes and are located inside the molding cylinder; then, the two positioning seats are snapped into the corresponding molding holes; finally, the first connecting part and the second connecting part are connected, and a release agent is applied to the molding tube.

[0035] The beneficial effects of this solution are as follows: the molding mechanism of this technical solution has the advantages of quick installation and convenient demolding. At the same time, it can flexibly adjust the position, tilt angle and deflection angle of hole defects. Attached Figure Description

[0036] Figure 1 This is a three-dimensional diagram of an apparatus for preparing porous rock samples according to the present invention;

[0037] Figure 2 A three-dimensional diagram showing the mating of the first arc-shaped connecting block and the second arc-shaped connecting block;

[0038] Figure 3 A 3D diagram of the forming mechanism;

[0039] Figure 4 This is a 3D diagram of the rotating unit. Detailed Implementation

[0040] The following detailed description illustrates the specific implementation method:

[0041] The reference numerals in the accompanying drawings include: base 1, support 2, fixing part 3, forming cylinder 4, forming hole 5, ring 6, first arc-shaped connecting block 7, second arc-shaped connecting block 8, first snap-fit ​​groove 9, second snap-fit ​​groove 10, forming tube 11, first connecting part 12, second connecting part 13, positioning seat 14, handle 15, mounting seat 16, universal ball 17, hollow rotating shaft 18, positioning bead 19.

[0042] Example

[0043] like Figure 1 The apparatus shown is for preparing a porous rock sample, including a base 1, a forming cylinder 4 and several forming mechanisms.

[0044] like Figure 1 As shown, the base 1 includes a support part 2 and a fixing part 3 connected in sequence. The support part 2 and the fixing part 3 are integrally formed. The fixing part 3 is located above the support part 2 and is coaxially arranged with the support part 2. The fixing part 3 has a cylindrical structure.

[0045] like Figure 1 and Figure 2As shown, the outer diameter of the forming cylinder 4 is equal to the inner diameter of the fixing part 3, and the lower end of the forming cylinder 4 is inserted into the fixing part 3. The outer diameter of the forming cylinder 4 is 220mm, the inner diameter is 200mm, and the height is 400mm. Several forming holes 5 are opened on the forming cylinder 4. A ring 6 is fitted on the outer surface of the forming cylinder 4. The inner diameter of the ring 6 is equal to the outer diameter of the forming cylinder 4. The ring 6 is used to fix the forming cylinder 4. Specifically, the forming cylinder 4 includes two first arc-shaped connecting blocks 7 and two second arc-shaped connecting blocks 8. The first arc-shaped connecting blocks 7 are 1 / 8 of the circumference, and the second arc-shaped connecting blocks 8 are 3 / 8 of the circumference. The forming cylinder 4 is a cylindrical structure formed by the alternating first arc-shaped connecting blocks 7 and second arc-shaped connecting blocks 8. The first arc-shaped connecting blocks 7 have first locking grooves 9 on their outer surfaces at both ends along their axial direction, and the second arc-shaped connecting blocks 8 have second locking grooves 10 on their inner surfaces at both ends along their axial direction. Through the cooperation of the first locking grooves 9 and the second locking grooves 10, the first arc-shaped connecting blocks 7 and the second arc-shaped connecting blocks 8 can be spliced. The forming holes 5 are distributed on the first arc-shaped connecting blocks 7 and the second arc-shaped connecting blocks 8. The shape of the forming holes 5 can be any one or more combinations of circles, squares, rhombuses, and polygons. The size of the forming holes 5 can also be adjusted according to actual needs. It should be noted that in this embodiment, there are two of each of the first arc-shaped connecting block 7 and the second arc-shaped connecting block 8, but this is not a limitation. The number and size of the first arc-shaped connecting block 7 and the second arc-shaped connecting block 8 can be adjusted according to actual needs, and the size of the first arc-shaped connecting block 7 and the second arc-shaped connecting block 8 can also be equal.

[0046] like Figure 3 and Figure 4 As shown, each molding mechanism includes a molding tube 11 and two rotating units. The molding tube 11 includes a first connecting part 12 and a second connecting part 13. The first connecting part 12 is inserted into the second connecting part 13 and can slide within the second connecting part 13. Each rotating unit includes a positioning seat 14, a handle 15, and a hollow rotating shaft 18. The left end of the handle 15 passes through the positioning seat 14 and is rotatably connected to the positioning seat 14. The left end of the handle 15 is threadedly connected to a mounting seat 16. A retaining ring is glued to the handle 15 between the positioning seat 14 and the mounting seat 16. A universal ball 17 is mounted on the mounting seat 16. The top of the universal ball 17 has a cylindrical hole that penetrates the bottom, and the cylindrical hole is coaxial with the universal ball 17. The hollow rotating shaft 18 is interference-fitted with the cylindrical hole. Positioning beads 19 are installed at both the upper and lower ends of the hollow shaft. The end of the molding tube 11 is rotatably connected to the positioning beads 19. It should be noted that the shape and size of the rotating unit and the molding tube 11 match the molding hole 5.

[0047] A method for preparing a porous rock sample includes the following steps:

[0048] S1: Apply release agent to the inner walls of both base 1 and molding cylinder 4;

[0049] S2: Insert the forming cylinder 4 into the base 1 and put the ring 6 on the forming cylinder 4;

[0050] S3: Install the molding mechanism on the molding cylinder 4 and seal the remaining useless molding holes 5. Specifically, pass the free ends of the first connecting part 12 and the second connecting part 13 through different molding holes 5 and place them inside the molding cylinder 4. Then, snap the two positioning seats 14 into the corresponding molding holes 5 respectively. Finally, insert the first connecting part 12 into the second connecting part 13 and apply a release agent to the molding tube 11.

[0051] S4: Prepare the slurry, pour the slurry into the molding cylinder 4 and vibrate to form the slurry;

[0052] S5: Curing test sample;

[0053] S6: Disassemble the molding mechanism and molding cylinder 4, and remove the sample: Specifically, remove the handle 15 from the mounting base 16, then remove the positioning base 14 from the molding cylinder 4, remove the ring 6 from the molding cylinder 4, remove the molding cylinder 4 from the base 1, and then pull the mounting base 16 and molding tube 11 off the sample to remove the sample.

[0054] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a porous rock sample, characterized in that: Includes the following steps: S1: Apply release agent to both the base and the inner wall of the molding cylinder; S2: Install the forming cylinder onto the base; S3: Install several molding mechanisms on the molding cylinder and apply a release agent to the molding mechanisms; S4: Prepare the slurry, pour the slurry into the molding cylinder and vibrate to form the shape; S5: Curing test sample; S6: Disassemble the molding mechanism and molding cylinder, and remove the sample; The forming cylinder in S2 has several forming holes, and the forming mechanism is matched with the forming holes; The forming mechanism in S3 includes a forming tube and two rotating units. The forming tube includes a first connecting part and a second connecting part, which are slidably and detachably connected. Each rotating unit includes a positioning seat, a mounting seat, a handle, and a hollow rotating shaft. The handle passes through the positioning seat and is detachably connected to the mounting seat. A universal ball is mounted on the mounting seat. A cylindrical hole penetrating the bottom is opened at the top of the universal ball, and the cylindrical hole is coaxial with the universal ball. The hollow rotating shaft is interference-fitted with the cylindrical hole. Positioning beads are installed at both the upper and lower ends of the hollow rotating shaft. The end of the forming tube is rotatably and detachably connected to the positioning beads.

2. The method for preparing a porous rock sample according to claim 1, characterized in that: The shape of the forming hole can be any combination of one or more of the following: circular, square, prismatic, and polygonal.

3. The method for preparing a porous rock sample according to claim 2, characterized in that: The forming cylinder in S2 includes several arc-shaped connecting blocks. The forming cylinder is a cylindrical structure formed by several arc-shaped connecting blocks, and the forming holes are distributed on the arc-shaped connecting blocks.

4. The method for preparing a porous rock sample according to claim 3, characterized in that: The forming cylinder in S2 is detachably connected to a ring.

5. The method for preparing a porous rock sample according to claim 3, characterized in that: A retaining ring is provided on the handle between the positioning seat and the mounting seat.

6. The method for preparing a porous rock sample according to claim 5, characterized in that: In S3, the molding mechanism is installed as follows: the free ends of the first connecting part and the second connecting part are both passed through different molding holes and located inside the molding cylinder. Then, the two positioning seats are snapped into the corresponding molding holes. Finally, the first connecting part and the second connecting part are connected together, and a release agent is applied to the molding tube.

Images