A method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks

Abstract

A true triaxial rock sample preparation method for weak and easily disintegrated layered rocks belongs to the field of rock engineering technology and includes four steps: cutting a plane, making a β-angle rock block, making a β- and ω-angle rock plate, and forming a standard rectangular rock sample. The method for making a β-angle rock block is to fix the plane rock mass, adjust the rock sample to the angle β between the plane 1 and the cutting line, and then cut it, and then translate the rock sample a distance m before cutting. The method for making a β- and ω-angle rock plate is to fix the cut β-angle rock block, adjust the rock sample to the angle ω between the plane 1 and the cutting line, and then cut it, and then translate the β-angle rock block a distance s before cutting. In the present invention, the utilization rate of rock samples is high, and rock samples of any angle and size can be cut. Multiple samples can be prepared in one cutting, and the success rate and effect of sample preparation are high. At the same time, the use of cold air cooling can prevent the cutting line from being overheated and broken, and prevent the rock layer from expanding and opening due to heat, and softening and disintegrating when exposed to water.

Description

Technical Field

[0001] The invention belongs to the technical field of rock mass engineering and relates to a sample preparation method, in particular to a true triaxial rock sample preparation method for weak and easily disintegrated layered rocks. Background Art

[0002] In mining, water conservancy and hydropower engineering, and tunnel engineering, weak, easily disintegrating layered rocks such as carbonaceous slate and phyllite are frequently encountered. These rocks have two distinct characteristics: first, they possess a pronounced bedding structure, resulting in significant anisotropy in their mechanical properties. The spatial relationship between the bedding pattern, the direction of in-situ stress, and the orientation of underground caverns has a significant impact on the stability of the surrounding rock mass. Second, these rock layers are extremely thin, with very low interlaminar bonding strength, which makes them susceptible to softening and disintegration upon contact with water, resulting in extremely poor rock mass properties. Engineering activities in these rock masses are prone to disasters such as landslides, spalling, and large deformations. Therefore, to more reliably assess the stability of weak, easily disintegrating layered rock masses, it is particularly important to fully understand the strength, deformation, and failure characteristics of these rock masses at different bedding angles under true triaxial stress.

[0003] The conventional method for preparing rock samples is saw cutting, which causes significant mechanical disturbance to the rock. Because the layers of weak, easily disintegrating layered rock are extremely thin and the interlayer bond strength is extremely low, the layers can easily open during sample preparation, leading to sample preparation failure. Wire cutting causes less disturbance to the rock, but both saw and wire cutting require cooling of the saw blade or cutting wire during the cutting process to prevent damage and to prevent the heat generated during cutting from causing the rock layers to expand and open. During sample preparation, water cooling is the conventional cooling method. However, weak, easily disintegrating layered rock easily softens and disintegrates when exposed to water, necessitating alternative cooling methods.

[0004] Different from conventional triaxial loading, true triaxial loading specimens need to consider the strike and tilt direction of the rock formation to form different combinations of loading angles β and ω, such as Figure 1 As shown, the patent application number 201810889698.5 introduces a method for preparing true triaxial layered rock samples, but it uses thin-walled drill bit drilling, saw blade cutting and other methods, which are not suitable for weak and easily disintegrated layered rocks. At present, there is no public literature reporting on the method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks, which is used to solve the technical problems in the prior art that true triaxial samples of weak and easily disintegrated layered rocks are easily damaged during the sampling process and the sampling success rate is low.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides a method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks, comprising the following steps:

[0007] Step 1: Cutting the plane

[0008] S1. Adjust the rock specimen so that the direction of layer 1 is perpendicular to the cutting line. Fix the rock specimen on the rock fixture, move the rock fixture horizontally to the cutting position, and adjust the height of the rock to 1-2 mm from the cutting line.

[0009] S2. Perform cutting on the rock specimen to cut out the first plane;

[0010] S3. Turn off the cooling mechanism and the wire cutting mechanism, adjust the rock height, and translate the rock specimen to the second cutting position, then cut the rock specimen to obtain a second plane and a flat rock mass;

[0011] Step 2: Making β-angle rock blocks

[0012] S1. Place one of the flat surfaces of the planar rock mass obtained in step 1 flat on a rock fixture. Adjust the rock specimen so that the strike direction of plane 1 forms an angle β with the cutting line. Secure the flat rock mass, move the rock fixture horizontally to the desired cutting position, and adjust the height of the rock to 1-2 mm from the cutting line.

[0013] S2. Cutting is performed on the flat rock mass to form the first plane;

[0014] S3. Turn off the cooling mechanism and the wire cutting mechanism, adjust the rock height, translate the plane rock mass by a distance of m, and cut on the plane rock mass to cut out a second plane, forming a rock block with an elevation angle of β;

[0015] Step 3: Production of β and ω angular rock plates

[0016] S1. Place one of the flat surfaces of the rock block cut at elevation β in step 2 on a rock jig. Adjust the rock specimen so that the strike of layer 1 forms an angle ω with the cutting line. Secure the rock block at elevation β, move the rock jig to the desired cutting position, and adjust the height of the rock to 1-2 mm from the cutting line.

[0017] S2. Cutting is performed on the rock block at an angle β to obtain the first plane;

[0018] S3. Turn off the cooling mechanism and the wire cutting mechanism, adjust the rock height, translate the rock block at an angle β by a distance s, and perform cutting on the rock block at an angle β to cut out the first slab at an angle β and ω.

[0019] S4. Repeat the operation of S3 until the last β and ω angular rock plate is cut;

[0020] Step 4: Standard rectangular rock sample forming

[0021] S1. Rotate the β and ω angled rock slabs cut in step 3 by 90° and secure them to the rock fixture. Move the rock fixture to the desired cutting position and adjust the rock height to 1-2 mm from the cutting line.

[0022] S2. Cutting on β and ω angular rock plates;

[0023] S3. Turn off the cooling mechanism and wire cutting mechanism, adjust the rock height, translate the β and ω angle rock plates by a distance s, and perform cutting on the β and ω angle rock plates to complete the first standard rectangular rock sample production;

[0024] S4. Repeat the operation of S3 until the last standard rectangular rock sample is cut, completing the production of true triaxial rock samples of weak and easily disintegrated layered rocks.

[0025] Preferably, in any of the above schemes, in S1, the method for fixing the rock block and adjusting the height of the rock to 1 to 2 mm from the cutting line is as follows: after adjusting the rock block to the desired position, tighten the positioning bolts on the rock clamp, fix the rock block on the rock clamp, translate the rock clamp to the position to be cut, and simultaneously start the elevator to adjust the height of the rock to 1 to 2 mm from the cutting line.

[0026] Preferably, in any of the above schemes, in said S2, the cutting method is to close the cooling box, start the air compressor, and when cold air flows out of the air hose, start the wire cutting mechanism and the elevator to perform cutting.

[0027] Preferably, in any of the above schemes, the specific operation of S3 is to sequentially close the elevator, wire cutting mechanism and air compressor, open the cooling box, adjust the rock height to an appropriate position, translate the rock block to the desired position, close the cooling box, start the air compressor, and when cold air flows out of the air hose, start the wire cutting mechanism and elevator for cutting.

[0028] In any of the above solutions, preferably, in step 2, m=x+c, wherein,

[0029] x and y are the lengths of the long side and short side of the true triaxial rock sample, respectively.

[0030] c is the rock consumption produced by one cutting.

[0031] In any of the above solutions, preferably, in step 3, s=y+c, wherein,

[0032] x and y are the lengths of the long side and short side of the true triaxial rock sample, respectively.

[0033] c is the rock consumption produced by one cutting.

[0034] As described above, the true triaxial rock sample preparation method of the present invention for weak and easily disintegrated layered rocks has the following beneficial effects:

[0035] 1. In the present invention, the rock clamp can be translated, and different positions can be cut according to different experimental requirements to form rock samples of different sizes, which greatly improves the flexibility of rock sample cutting. At the same time, the rock clamp can fix the rock to prevent the rock from moving during the cutting process, ensuring the stability of rock cutting and thus ensuring the quality of sample preparation.

[0036] 2. In the present invention, the air compressor is used to generate cold air for cooling, which can effectively improve the cooling effect and avoid the cutting line from being overheated and broken. At the same time, it can also effectively prevent the layer rock from expanding and opening due to heat, and prevent the rock from softening and disintegrating when it comes into contact with water, thereby effectively ensuring the quality of rock sample preparation.

[0037] 3. In the present invention, diamond cutting wire is used to cut the rock sample, which reduces the mechanical disturbance to the rock. At the same time, the surface of the prepared rock sample is made smooth, which avoids sample grinding and reduces the mechanical damage to the rock.

[0038] 4. In the present invention, the rock sample cutting method is easy to understand and simple to operate, can maximize the use of rock specimens, improve the utilization rate of rock specimens, can achieve the cutting of layered rock specimens of any angle and any size, and can produce multiple rock specimens in one cutting process, greatly improving the success rate and efficiency of sample preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Shown is a schematic diagram of a layered true triaxial rock sample in the prior art.

[0040] Figure 2 It shows the structural schematic diagram of the true triaxial rock sampling device for weak and easily disintegrated layered rock in the present invention.

[0041] Figure 3 Shown is a structural diagram of the wire cutting mechanism.

[0042] Figure 4 Shown is a schematic structural diagram of the supporting mechanism.

[0043] Figure 5 Shown is a schematic diagram of the cooling mechanism.

[0044] Figure 6 Shown is a schematic diagram of the rock clamp structure.

[0045] Figure 7 Schematic diagram showing an irregular rock specimen placed on a rock fixture.

[0046] Figure 8 Schematic diagram of a flat rock specimen placed on a rock fixture.

[0047] Figure 9 Schematic diagram of a β-angle rock block placed on a rock fixture.

[0048] Figure 10 Schematic diagram of the β and ω angle rock plates placed on the rock fixture.

[0049] Figure 11 Schematic diagram of the standard size rock samples obtained by cutting.

[0050] Component number description

[0051] 1- rock layer; 2- wire cutting mechanism; 20- main frame; 21- wire winding drum; 22- tensioning pulley; 23- guide wheel; 24- cutting wire; 3- bearing mechanism; 30- bearing frame; 31- rock fixture; 310- slider; 311- positioning hole; 312- positioning bolt; 313- locking nut; 314- boss; 315- fixture body; 316- cutting chamber; 32- elevator; 33- pushing hand wheel; 34- fixture slide; 35- baffle slide; 36- air inlet; 37- air outlet; 4- cooling mechanism; 40- air compressor; 41- vortex tube; 42- air supply hose; 43- air nozzle; 44- transparent baffle; 45- cooling box; 50- irregular rock specimen; 51- plane rock mass; 52- rock block with elevation β angle; 53- rock plate with β and ω angle; 54- rectangular parallelepiped specimen. DETAILED DESCRIPTION

[0052] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0053] See also Figures 2 to 11 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0054] Example 1

[0055] See also Figure 2-6 The present invention provides a true triaxial rock sample preparation device for weak and easily disintegrated layered rocks, including a wire cutting mechanism 2, a supporting mechanism 3 and a cooling mechanism 4. The supporting mechanism 3 includes a supporting frame 30 that can move up and down to fix the rock mass. A detachable transparent baffle 44 is provided around the supporting frame 30. The cutting line 24 of the wire cutting mechanism 2 is located in the supporting frame 30, and the cold air outlet end of the cooling mechanism 4 is parallel to the cutting line 24.

[0056] In this embodiment, the sample preparation device consists of a wire cutting mechanism 2 for cutting the rock mass, a supporting mechanism 3 for securing and moving the rock mass, and a cooling mechanism 4 for cooling the cutting wire 24. During the sample preparation process, the rock mass is secured to the supporting mechanism 3, such that the rock layer 1 forms the desired angle with the cutting wire 24. Once secured, the wire cutting mechanism 2, supporting mechanism 3, and cooling mechanism 4 are activated, working together to cut the rock mass. In this embodiment, the use of a diamond cutting wire 24 to cut the rock sample reduces mechanical disturbance to the rock. This also results in a smooth surface for the prepared rock sample, avoiding sample grinding and minimizing mechanical damage to the rock.

[0057] The supporting mechanism 3 comprises an elevator 32, a supporting frame 30, and a rock fixture 31. During the cutting process, the rock mass to be cut is placed in the rock fixture 31. The elevator 32 drives the supporting frame 30 up and down, thereby driving the rock mass fixed to the supporting frame 30 up and down. This, in conjunction with the wire cutting mechanism 2, achieves the desired rock mass. The cooling air generated by the cooling mechanism 4 cools the cutting wire 24, effectively improving the cooling effect and preventing the cutting wire 24 from overheating and breaking. It also effectively prevents thermal expansion of the rock layers and softening and disintegration of the rock upon contact with water, effectively ensuring the quality of rock sample preparation.

[0058] For further description of the above embodiments, see Figure 3 The wire cutting mechanism 2 includes a main frame 20, on which a lift 32 is provided, and the supporting frame 30 is connected to the lift 32. A wire winding drum 21 is provided on the top of the main frame 20, and two groups of guide wheels 23 are provided below the wire winding drum 21. At least one group of tensioning wheels 22 is provided between the wire winding drum 21 and the guide wheels 23. The guide wheels 23 are located in the supporting frame 30, and the cutting wire 24 is wound around the wire winding drum 21, the tensioning wheel 22 and the guide wheel 23.

[0059] When this embodiment is used, the main frame 20 includes a base plate 201, a door-shaped frame 202 welded to the base plate 201, and the wire winding drum 21 is arranged in the middle position at the top of the door-shaped frame 202. The side wall of the door-shaped frame 202 is fixedly connected with a vertical plate 203, and two tensioning wheels 22 are fixed on the vertical plate 203. The two sets of guide wheels 23 are respectively connected to the vertical plate 203 through a long strip connecting plate 204. During the cutting process, the wire winding drum 21, the tensioning wheel 22 and the guide wheel 23 cooperate with each other to drive the cutting line 24 to move at high speed to achieve cutting of the rock mass. Of course, the structure of the main frame 20 is not limited to this, and other frame structures that can play a connecting and supporting role are all acceptable. Those skilled in the art can make corresponding adjustments according to the usage situation, and they will not be described in this embodiment.

[0060] In this embodiment, the lifting device 32 drives the supporting frame 30 to move up and down, thereby driving the rock mass to be cut fixed on the supporting frame 30 to move up and down, cooperating with the wire cutting mechanism 2 to achieve cutting of the rock mass to be cut.

[0061] In this embodiment, the number of tensioning wheels 22 is not limited to two, and can be selected accordingly according to usage, such as one or three tensioning wheels 22.

[0062] For further description of the above embodiments, see Figure 6 The rock clamp 31 includes a clamp body 315, with a slider 310 fixed to the middle of the lower surface of the clamp body 315. The upper surface of the clamp body 315 is provided with several groups of evenly distributed bosses 314 along its length, with a cutting cavity 316 formed between any two adjacent groups of bosses 314. Positioning holes 311 are defined at both ends of each group of bosses 314, each of which is provided with a positioning bolt 312 and a locking nut 313 that matches the positioning bolt 312.

[0063] When this embodiment is used, the bosses 314 are arranged parallel and evenly on the clamp body 315 for placing rocks. Connecting columns are fixedly connected at both ends of the bosses 314, and the connecting columns are integrally formed with the bosses 314. Positioning holes 311 are symmetrically formed on the connecting columns at both ends of each boss 314, and are equipped with positioning bolts 312 and locking nuts 313 for securing the rock during the rock cutting process. Specifically, during the rock cutting process, the rock to be cut is placed on the clamp body 315, and the positioning bolts 312 are pushed so that the ends of the positioning bolts 312 contact and press the rock to be cut. Once in place, the locking nuts 313 are tightened.

[0064] In this embodiment, a cylindrical positioning block is fixedly connected to the end of the positioning bolt 312 located inside the clamp body 315. The diameter of the cylindrical positioning block is larger than the diameter of the positioning bolt 312, thereby increasing the contact area with the rock to be cut, thereby further ensuring the fixing effect of the rock to be cut, ensuring the stability of the rock to be cut during the cutting process, and thus ensuring the cutting quality.

[0065] In this embodiment, a cutting cavity 316 is formed between any two adjacent groups of bosses 314 for the cutting line 24 to penetrate the rock mass during cutting.

[0066] For further description of the above embodiments, see Figure 4 、 6 The middle portion of the upper surface of the supporting frame 30 is recessed inward along its length to form a fixture slide 34 that matches the slider 310. A propulsion hole is provided below the supporting frame 30, and a detachable propulsion handwheel 33 is provided in the propulsion hole. The propulsion handwheel 33 is connected to the slider 310.

[0067] In use, the support frame 30 is provided with a fixture slot 34 and a push handle 33, which cooperates with a slider 310 on the rock fixture 31 to control the translation of the rock fixture 31 on the support frame 30. A fixed wrench is provided on the push handle 33. When the fixed wrench is loosened, the handwheel can be rotated to adjust the position. When tightened, the handwheel is locked, ensuring that the rock fixture 31 will not move.

[0068] For further description of the above embodiments, see Figure 4 The supporting frame 30 is provided with baffle slots 35 on all four sides, and the baffle 44 can be movably set on the supporting frame 30 through the baffle slots 35. The baffle 44 and the supporting frame 30 form a cooling box 45.

[0069] When this embodiment is used, a baffle groove 35 is cut on the supporting frame 30 for placing the baffle 44. The baffle 44 is detachable. The supporting frame 30 and the baffle 44 together constitute a cooling box 45 to improve the cooling effect. The cooling box 45 can be closed and opened by placing or removing the baffle 44.

[0070] For further description of the above embodiments, see Figure 4 、 5 The cooling mechanism 4 includes an air compressor 40 , the output shaft of the air compressor 40 is connected to a cooling box 45 via an air hose 42 , and a vortex tube 41 is provided between the output shaft of the air compressor 40 and the cooling box 45 .

[0071] When this embodiment is in use, the air hose 42 extends into the cooling box 45 through the air inlet 36 on the supporting frame 30. The cold air outlet end of the air hose 42 is fixed in the cooling box 45 with tape, located above the guide wheel 23 and placed parallel to the cutting line 24. A plurality of air nozzles 43 are provided on the air hose 42 for spraying cold air toward the cutting line 24 and the rock. The cold air circulates below the cooling box 45 and is discharged from the air outlet 37 above the cooling box 45.

[0072] In this embodiment, the air compressor 40 introduces compressed air into the vortex tube 41, and the high-pressure air is separated into hot and cold air in the vortex tube 41. The cold air flows from one end of the vortex tube 41 through the air hose 42 to the cooling box 45, thereby cooling the cutting line and the rock during the cutting process, and the hot air flows out from the other end of the vortex tube 41.

[0073] For further description of the above embodiments, see Figure 4 、 5 An air inlet 36 and two air outlets 37 are provided on the top of the supporting frame 30. The cold air outlet end of the air hose 42 extends into the cooling box 45 after passing through the air inlet 36. The cold air outlet end of the air hose 42 is located above the guide wheel 23 and parallel to the cutting line 24. Several air nozzles 43 are provided at the cold air outlet end of the air hose 42. The cutting line 24 enters and exits the cooling box 45 through the two air outlet holes 37.

[0074] In this embodiment, the support frame 30 is provided with an air inlet 36 and an air outlet 37, which are used to receive a gas hose 42 for cooling air, exhausting hot air from the cooling box 45, and allowing the diamond cutting wire 24 to enter and exit the cooling box 45. The long connecting plate 204 passes through the two air outlets 37 and enters the cooling box 45, allowing the cutting wire 24 to enter and exit the cooling box 45 through the two air outlets 37.

[0075] In this embodiment, the provision of the air nozzle 43 can increase the cold air ejection area, thereby effectively improving the cooling effect on the cutting line 24 when the same amount of cold air is ejected, thereby achieving the purpose of saving resources.

[0076] Example 2

[0077] See also Figure 2-11 The present invention provides a true triaxial rock sample preparation method for weak and easily disintegrated layered rock, comprising the following steps:

[0078] Step 1: Cutting the plane

[0079] S1. Figure 7As shown, place the irregularly shaped rock specimen on the rock fixture 31, adjust the rock specimen so that the direction of the layer 1 is perpendicular to the cutting line 24, tighten the positioning bolt 312 on the rock fixture 31 with the locking nut 313, fix the rock specimen on the rock fixture 31, translate the rock fixture 31 to the position to be cut, and adjust the height of the rock to 2 mm above the cutting line 24;

[0080] S2. Close the cooling box 45, start the air compressor 40, and when the cold air nozzle 43 flows out of the cold air, start the wire cutting mechanism 2 and the elevator 32, and cut the first plane on the rock specimen;

[0081] S3. The elevator 32, the wire cutting mechanism 2, and the air compressor 40 are sequentially closed, and the cooling box 45 is opened. The rock is adjusted to a suitable height (a suitable position refers to a position where the rock specimen can be adjusted). The rock specimen is then translated to the second cutting position. The cooling box 45 is closed, and the air compressor 40 is started. When cold air flows out of the air nozzle 43, the wire cutting mechanism 2 and the elevator 32 are started to cut the rock specimen, thereby cutting out the second plane. This completes the creation of the cutting plane to obtain the planar rock mass 51.

[0082] Step 2: Making β-angle rock blocks

[0083] S1. Figure 8 As shown, one of the planes of the planar rock mass 51 obtained by cutting in step 1 is placed flat on the rock fixture 31, and the rock specimen is adjusted so that the direction of the plane 1 forms an angle β with the cutting line 24. The positioning bolts 312 on the rock fixture 31 are tightened to fix the planar rock mass 51 on the rock fixture 31, and the rock fixture 31 is translated to the position to be cut. At the same time, the elevator 32 is started to adjust the height of the rock to 2 mm above the cutting line 24.

[0084] S2. Close the cooling box 45 and start the air compressor 40. When the air nozzle 43 has a cold flow out, start the wire cutting mechanism 2 and the elevator 32 to cut the rock mass 51 on the plane, cutting out the first plane;

[0085] S3. Sequentially shut down the elevator 32, the wire cutting mechanism 2, and the air compressor 40. Open the cooling box 45, adjust the rock height to an appropriate position, translate the rock specimen a distance m, close the cooling box 45, start the air compressor 40, and when cold air flows out of the air nozzle 43, start the wire cutting mechanism 2 and the elevator 32 to cut the flat rock mass 51, creating a second flat surface and forming a rock block 52 at an angle β.

[0086] Step 3: Production of β and ω angular rock plates 53

[0087] S1. Figure 9As shown, place one of the flat surfaces of the rock block 52 cut at an elevation β angle in step 2 flat on the rock fixture 31. Adjust the rock specimen so that the direction of the layer 1 forms an angle ω with the cutting line 24. Tighten the positioning bolts 312 on the rock fixture 31 to secure the rock specimen to the rock fixture 31. Move the rock fixture 31 to the position to be cut, and start the elevator 32 to adjust the height of the rock to 2 mm above the cutting line 24.

[0088] S2. Close the cooling box 45, start the air compressor 40, when the air nozzle 43 has a cold air outflow, start the wire cutting mechanism 2, and cut the rock block 52 at an elevation β angle, cutting out the first plane;

[0089] S3. Sequentially shut down the elevator 32, the wire cutting mechanism 2, and the air compressor 40. Open the cooling box 45, adjust the rock height to an appropriate position, translate the rock block 52 at an angle of β by a distance s, close the cooling box 45, and start the air compressor 40. When cold air flows out of the air nozzle 43, start the wire cutting mechanism 2 and the elevator 32, and cut the rock block 52 at an angle of β, thus cutting the first rock plate 53 at an angle of β and ω.

[0090] S4 repeats the operation of S3 until the last piece of β, ω angle rock plate 53 is cut;

[0091] Step 4: Standard rectangular rock sample forming

[0092] S1. Figure 10 As shown, rotate the β and ω angle rock plates 53 cut in step 3 by 90°, tighten the positioning bolts 312 on the rock fixture 31, fix the rock specimen on the rock fixture 31, translate the rock fixture 31 to the position to be cut, start the elevator 32, and adjust the height of the rock to 2 mm above the cutting line 24;

[0093] S2. Close the cooling box 45 and start the air compressor 40. When the air nozzle 43 has a cold air flow, start the wire cutting mechanism 2 and the elevator 32 to cut on the β and ω angle rock plate 53 to complete the first cutting.

[0094] S3. Sequentially shut down the elevator 32, the wire cutting mechanism 2, and the air compressor 40. Open the cooling box 45, adjust the rock height to an appropriate position, translate the β and ω angle rock plates 53 by a distance s, close the cooling box 45, start the air compressor 40, and when cold air flows out of the air nozzle 43, start the wire cutting mechanism 2 and the elevator 32 to cut the β and ω angle rock plates 53, completing the first standard cuboid rock sample.

[0095] S4. Repeat the operation of S3 until the last standard rectangular rock sample is cut, and the true triaxial rock sample of the weak and easily disintegrated layered rock is prepared. Figure 11 shown.

[0096] In this embodiment, in S1 of step 1, step 2, step 3 and step 4, the rock height is not limited to being adjusted to 2 mm above the cutting line 24. Corresponding adjustments can be made according to actual operations, and the rock height can be adjusted to within a range of 1 to 2 mm above the cutting line 24.

[0097] In this embodiment, in step 2, m=x+c, and in step 3, s=y+c, wherein,

[0098] x and y are the lengths of the long side and short side of the true triaxial rock sample, respectively.

[0099] c is the rock consumption produced by one cutting.

[0100] Example 3

[0101] The true triaxial rock sample preparation device for weak and easily disintegrated layered rock includes four parts when preparing rock samples: cutting plane, making β-angle rock blocks, making β and ω-angle rock plates 53, and forming standard rectangular rock samples. Diamond cutting wire 24 is used to cut the rock sample, which reduces the mechanical disturbance to the rock. On the other hand, it also makes the surface of the prepared rock sample smoother, avoids sample grinding, and reduces mechanical damage to the rock. The sample preparation device is equipped with a movable rock clamp 31, which makes the rock sample preparation process convenient and simple. The sample preparation device uses compressed air to pass through the vortex tube 41 to generate cold air to cool the cutting wire 24 and the rock mass, which can solve the problems of overheating and breaking of the cutting wire 24, the opening of the rock layer due to heat, and the softening and disintegration of weak and easily disintegrated rocks when exposed to water. In this way, a method for preparing weak and easily disintegrated layered true triaxial rock samples is formed. Taking the preparation of weak and easily disintegrated layered true triaxial rock samples with a size of 100mm×50mm×50mm as an example, the method includes the following steps:

[0102] Step 1: Cutting the plane

[0103] S1. Figure 7 As shown, place an irregularly shaped rock specimen on the rock fixture 31, adjust the rock specimen so that the direction of the layer 1 is perpendicular to the cutting line 24, tighten the positioning bolt 312 on the rock fixture 31 with the locking nut 313, fix the rock specimen on the rock fixture 31, translate the rock fixture 31 to the position to be cut, and adjust the height of the rock to 1 mm above the cutting line 24;

[0104] S2. Close the cooling box 45, start the air compressor 40, and when the cold air nozzle 43 flows out of the cold air, start the wire cutting mechanism 2 and the elevator 32, and cut out the first plane on the rock specimen;

[0105] S3. The elevator 32, the wire cutting mechanism 2, and the air compressor 40 are sequentially closed, and the cooling box 45 is opened. The rock is adjusted to a suitable height (a suitable position refers to a position where the rock specimen can be adjusted). The rock specimen is then translated to the second cutting position. The cooling box 45 is closed, and the air compressor 40 is started. When cold air flows out of the air nozzle 43, the wire cutting mechanism 2 and the elevator 32 are started to cut the rock specimen, thereby cutting out the second plane. This completes the creation of the cutting plane to obtain the planar rock mass 51.

[0106] Step 2: Making 100mm high β angle rock blocks

[0107] S1. Figure 8 As shown, one of the planes of the planar rock mass 51 obtained by cutting in step 1 is placed flat on the rock fixture 31, and the rock specimen is adjusted so that the direction of the plane 1 forms an angle β with the cutting line 24. The positioning bolts 312 on the rock fixture 31 are tightened to fix the planar rock mass 51 on the rock fixture 31, and the rock fixture 31 is translated to the position to be cut. At the same time, the elevator 32 is started to adjust the height of the rock to 1 mm above the cutting line 24.

[0108] S2. Close the cooling box 45 and start the air compressor 40. When the air nozzle 43 has a cold flow out, start the wire cutting mechanism 2 and the elevator 32 to cut the rock mass 51 on the plane, cutting out the first plane;

[0109] S3. Sequentially close the elevator 32, the wire cutting mechanism 2, and the air compressor 40, open the cooling box 45, adjust the rock height to an appropriate position, translate the rock specimen 101 mm, close the cooling box 45, start the air compressor 40, and when cold air flows out of the air nozzle 43, start the wire cutting mechanism 2 and the elevator 32 to cut the flat rock mass 51, creating a second flat surface and forming a rock block with a β-angle of 100 mm.

[0110] Step 3: Production of 100mm high and 50mm thick β and ω angular rock plates 53

[0111] S1. Figure 9 As shown, place one of the flat surfaces of the 100 mm high-angle rock block cut in step 2 flat on the rock fixture 31. Adjust the rock specimen so that the direction of the layer 1 forms an angle ω with the cutting line 24. Tighten the positioning bolts 312 on the rock fixture 31 to secure the rock specimen to the rock fixture 31. Move the rock fixture 31 to the desired cutting position, and start the elevator 32 to adjust the height of the rock to 1 mm above the cutting line 24.

[0112] S2. Close the cooling box 45, start the air compressor 40, when the air nozzle 43 has a cold air outflow, start the wire cutting mechanism 2, and cut the rock block 52 at an elevation β angle, cutting out the first plane;

[0113] S3. Sequentially shut down the elevator 32, the wire cutting mechanism 2, and the air compressor 40. Open the cooling box 45, adjust the rock height to the appropriate position, translate the rock block 52 at an elevation of β by 51 mm, close the cooling box 45, start the air compressor 40, and when cold air flows out of the air nozzle 43, start the wire cutting mechanism 2 and the elevator 32 to cut the rock block 52 at an elevation of β, producing the first 100 mm high and 50 mm thick β, ω angle rock slab 53.

[0114] S4 repeat the operation of S3 until the last piece of 100mm high 50mm thick β, ω angle rock plate 53 cutting is completed;

[0115] Step 4: Forming a 100mm×50mm×50mm standard rectangular rock sample

[0116] S1. Figure 10 As shown, the 100 mm high and 50 mm thick β, ω angle rock plate 53 cut in step 3 is rotated 90 degrees, the positioning bolts 312 on the rock fixture 31 are tightened, the rock specimen is fixed on the rock fixture 31, the rock fixture 31 is translated to the position to be cut, the elevator 32 is started, and the height of the rock is adjusted to 1 mm above the cutting line 24;

[0117] S2. Close the cooling box 45 and start the air compressor 40. When the air nozzle 43 has a cold air flow, start the wire cutting mechanism 2 and the elevator 32, cutting on the 100mm high 50mm thick β, ω angle rock plate 53 to complete the first cutting;

[0118] S3. Sequentially shut down the elevator 32, the wire cutting mechanism 2, and the air compressor 40. Open the cooling box 45, adjust the rock height to the appropriate position, translate the β and ω angle rock plates 53 by 51 mm, close the cooling box 45, start the air compressor 40, and when cold air flows out of the air nozzle 43, start the wire cutting mechanism 2 and the elevator 32. Cut the 100 mm high and 50 mm thick β and ω angle rock plates 53, completing the first standard cuboid rock sample.

[0119] S4. Repeat the operation of S3 until the last standard rectangular rock sample is cut, and the true triaxial rock sample of 100mm×50mm×50mm soft and easily disintegrated layered rock is completed. Figure 11 shown.

[0120] In summary, the present invention achieves high rock specimen utilization, enabling the cutting of layered rock samples at any angle and size. Multiple rock samples can be prepared in a single cut, resulting in a high success rate and high efficiency. Furthermore, the use of cold air for cooling prevents the cutting wire from overheating and breaking, while also preventing thermal expansion and softening of the rock layer upon contact with water. Therefore, the present invention effectively overcomes the shortcomings of existing technologies and possesses high industrial value.

[0121] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A true triaxial rock sample preparation method for weak and easily disintegrated layered rock, characterized in that: The following steps are involved: Step 1: Cutting the plane S1. Adjust the rock specimen to the direction of layer 1 perpendicular to the cutting line (24), fix the rock specimen on the rock fixture (31), translate the rock fixture (31) to the position to be cut, and adjust the height of the rock to 1 to 2 mm from the cutting line (24); S2. Perform cutting on the rock specimen to cut out the first plane; S3. Turn off the cooling mechanism (4) and the wire cutting mechanism (2), adjust the rock height, and translate the rock specimen to the second position to be cut, cut the rock specimen, cut out the second plane, and obtain a planar rock mass (51); Step 2: Making β-angle rock blocks S1. Place one of the planes of the planar rock mass (51) obtained in step 1 flat on the rock fixture (31), adjust the rock specimen so that the strike direction of plane 1 forms an angle β with the cutting line (24), fix the planar rock mass (51), translate the rock fixture (31) to the position to be cut, and adjust the height of the rock to 1 to 2 mm from the cutting line (24); S2. Cutting the plane rock mass (51) to cut out the first plane; S3. Turn off the cooling mechanism (4) and the wire cutting mechanism (2), adjust the rock height, translate the rock specimen by a distance of m, cut it on the plane rock mass (51), cut out a second plane, and form a rock block (52) with an elevation angle of β. Step 3: Production of β and ω angular rock plates (53) S1. Place one of the planes of the rock block (52) with an elevation of β angle cut out in step 2 flat on the rock fixture (31), adjust the rock specimen so that the direction of the plane 1 forms an angle ω with the cutting line (24), fix the rock block (52) with an elevation of β angle, translate the rock fixture (31) to the position to be cut, and adjust the height of the rock to 1 to 2 mm from the cutting line (24); S2. Cutting the rock block (52) at an elevation of β to create a first plane; S3. Turn off the cooling mechanism (4) and the wire cutting mechanism (2), adjust the rock height, translate the rock block (52) at an elevation of β by a distance s, and cut the rock block (52) at an elevation of β to cut out the first β, ω angle rock plate (53); S4 repeats the operation of S3 until the last piece of β, ω angle rock plate (53) is cut; Step 4: Standard rectangular rock sample forming S1. The β and ω angle rock plates (53) cut out in step three are rotated 90° and fixed on the rock fixture (31). The rock fixture (31) is moved to the position to be cut and the height of the rock is adjusted to 1 to 2 mm from the cutting line (24). S2. Cutting on β, ω angular rock plate (53); S3. Turn off the cooling mechanism (4) and the wire cutting mechanism (2), adjust the rock height, translate the β, ω angle rock plate (53) by a distance of s, cut the β, ω angle rock plate (53) to complete the first standard rectangular rock sample production; S4. Repeat the operation of S3 until the last standard rectangular rock sample is cut, completing the production of true triaxial rock samples of weak and easily disintegrated layered rocks.

2. The true triaxial rock sample preparation method for weak and easily disintegrated layered rock according to claim 1, characterized in that: In the above-mentioned S1, the method for fixing the rock block and adjusting the height of the rock to 1 to 2 mm from the cutting line (24) is as follows: after adjusting the rock block to the desired position, tightening the positioning bolt (312) on the rock clamp (31), fixing the rock block on the rock clamp (31), translating the rock clamp (31) to the position to be cut, and simultaneously starting the elevator (32) to adjust the height of the rock to 1 to 2 mm from the cutting line (24).

3. The method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks according to claim 1, characterized in that: In the above-mentioned S2, the cutting method is to close the cooling box (45), start the air compressor (40), and when cold air flows out of the air hose (42), start the wire cutting mechanism (2) and the elevator (32) to cut.

4. The method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks according to claim 1, characterized in that: The specific operation of S3 is to sequentially close the elevator (32), the wire cutting mechanism (2) and the air compressor (40), open the cooling box (45), adjust the rock height to an appropriate position, translate the rock block to the desired position, close the cooling box (45), start the air compressor (40), and when cold air flows out of the air hose (42), start the wire cutting mechanism (2) and the elevator (32) to perform cutting.

5. The method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks according to claim 1, characterized in that: In the step 2, m=x+c, where x and y are the lengths of the long side and short side of the true triaxial rock sample, respectively. c is the rock consumption produced by one cutting.

6. The method for preparing true triaxial rock samples of weak and easily disintegrated layered rocks according to claim 1, characterized in that: In step 3, s=y+c, where x and y are the lengths of the long side and short side of the true triaxial rock sample, respectively. c is the rock consumption produced by one cutting.

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