In-situ high-fidelity sampling device and method for layered rock mass

Abstract

The application provides a layered rock mass in-situ high-fidelity sampling device and method, which comprises a supporting platform and a sampling unit, the supporting platform is provided with a sliding rail, the sampling unit is slidably connected to the supporting platform through the sliding rail, the sampling unit is hollow inside for accommodating the layered rock mass sample, the sampling unit comprises a detachably connected pressure maintaining part and a drilling part, the inside of the side wall of the pressure maintaining part is circumferentially provided with a pressure maintaining bag, the pressure maintaining bag is used for applying uniform radial pressure to the layered rock mass sample inside during the sampling process to simulate the in-situ confining pressure state, the front end of the drilling part is circumferentially provided with a plurality of cutterheads for cutting the rock mass, the cutting edges of the cutterheads are directed to the rock surface, and the high-pressure water cutting unit is arranged on the side of the inner wall of the drilling part close to the pressure maintaining part, the pressure maintaining bag is arranged on the inside of the pressure maintaining part, the layered rock mass sample is subjected to real-time radial pressure constraint, and the rock sample damage caused by stress release is inhibited; the nondestructive cutting technology of high-pressure water flow is adopted to replace the traditional torsional breaking mode, and the mechanical damage to the root of the rock sample is eliminated from the source.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to a high-fidelity in-situ sampling device and method for layered rock masses. Background Technology

[0002] Layered rock masses, a common rock structure type found in oil and gas reservoirs, slope engineering, and underground caverns, exhibit significant transverse anisotropy in their physical and mechanical properties. Obtaining in-situ rock samples that maintain the original formation stress state and intact internal structure is crucial for conducting precise mechanical tests and assessing rock mass stability. Currently, conventional drilling techniques such as diamond wireline coring are widely used in engineering for rock sample collection. However, these techniques are primarily designed for intact, homogeneous rock masses. When applied to layered rock masses, during drilling, vibrations, fluctuations in drill bit torque, and collisions and friction between the core tube and the rock sample can easily induce stress concentration at weak interlayers or bedding planes. This can lead to problems such as interlayer delamination, fragmentation, or macroscopic fracture propagation in the core sample, making the retrieved rock sample unable to accurately reflect the in-situ layered structural characteristics and thus losing its engineering representativeness.

[0003] Furthermore, conventional sampling techniques have inherent drawbacks in two core aspects, making it difficult to achieve the goal of "high-fidelity" sampling. Firstly, regarding stress retention, existing technologies lack an effective in-situ stress-locking mechanism. When the core root is broken, the rock sample instantly detaches from the original stress field, resulting in radial expansion and micro-fracture generation due to stress release, which significantly alters the mechanical properties of the rock sample. Secondly, in terms of reducing sampling disturbance, the rotation and vibration of existing drilling tools, as well as the friction between the rock sample and the borehole wall, all generate strong disturbances to the rock sample, leading to damage to its internal structure. This is particularly true for layered rock masses, where such disturbances are more likely to trigger interlayer displacement or fracture propagation, severely compromising the integrity of the rock sample. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-fidelity in-situ sampling device for layered rock masses, which can solve the problems of large rock sample disturbance and low fidelity in traditional layered rock mass sampling techniques.

[0005] Therefore, the present invention adopts the following technical solution: A high-fidelity in-situ sampling device for layered rock masses includes a support platform and a sampling unit. The support platform is equipped with a slide rail, and the sampling unit is slidably connected to the support platform via the slide rail. The sampling unit is hollow inside to accommodate layered rock samples. The sampling unit includes a detachably connected pressure-holding section and a drilling section. A pressure-holding bladder is circumferentially located on the inner side wall of the pressure-holding section. The pressure-holding bladder applies uniform radial pressure to the layered rock sample inside during sampling to simulate in-situ confining pressure. The front end of the drilling section is circumferentially equipped with several cutterheads for cutting the rock mass, with the cutting edges of the cutterheads facing the rock surface. A high-pressure water cutting unit is located on the inner wall of the drilling section near the pressure-holding section. The high-pressure water cutting unit can cut the rock sample between the drilling section and the pressure-holding section to form a smooth cutting surface.

[0006] Based on the above technical solutions, the present invention may also employ the following further technical solutions, or combine these further technical solutions: The high-pressure water cutting unit includes a high-pressure water inlet for receiving high-pressure water and a high-pressure water outlet for outputting high-pressure water, with multiple high-pressure water outlets arranged along the height directions of two opposite inner walls of the drilling section.

[0007] The pressure-holding bladder is a hydraulic bladder with an inflation port.

[0008] A pressure sensor is axially provided on the side wall, and the pressure sensor is nested and adjacent to the pressure-holding bladder. The confining pressure of the pressure-holding bladder is dynamically adjusted according to the feedback of the pressure sensor to simulate the in-situ confining pressure state.

[0009] The cutter head includes a main disc and cutting teeth, with the cutting teeth facing the rock surface and the surface of the cutting teeth being spherical.

[0010] The slide rail is provided with a locking structure, which is a layer of friction material.

[0011] The internal cavity of the sampling unit has a rectangular cross-section.

[0012] The pressure-retaining bladder has a raised textured surface, thereby increasing the friction between it and the layered rock sample inside.

[0013] The purpose of this invention is also to overcome the shortcomings of the prior art and provide a high-fidelity in-situ sampling method for layered rock masses, which can solve the problems of large rock sample disturbance and low fidelity in traditional layered rock mass sampling techniques.

[0014] Therefore, the present invention adopts the following technical solution: A high-fidelity in-situ sampling method for layered rock masses includes the following steps: Step 1: Select the sampling point of the layered rock mass, clean up the surrounding pumice, debris and weathered layer, place the support platform flat, assemble the sampling device completely and connect it to the control system; Step 2: After calibrating the drilling direction with the positioning instrument, start the control system to drive the sampling unit forward along the slide rail, while controlling the cutterhead to rotate at low speed to cut the rock surface; Step 3: After the initial formation of the layered rock mass sample, the pressure-holding bladder is filled with water through the filling port and expands to apply uniform radial pressure to the inner layered rock mass sample, simulating the in-situ confining pressure state. The pressure value of the pressure-holding bladder can be preset according to the formation stress and adjusted in real time through the pressure sensor to suppress the volume expansion or microcrack generation of the layered rock mass sample caused by stress release. Step 4: After drilling is completed and the internal pressure reaches a stable level, the high-pressure water cutting unit is activated to cut the root of the layered rock sample at the junction with the bedrock. Step 5: Transfer the rock samples from the pressure-holding section and its internal layered rock mass to the laboratory for subsequent tests.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: by setting a pressure-holding bladder inside the pressure-holding part, the layered rock sample is subjected to real-time radial pressure constraint, which inhibits the rock sample damage caused by stress release; the high-pressure water flow non-destructive cutting technology is used to replace the traditional torsion method, which eliminates the mechanical damage to the root of the rock sample from the root. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the inner wall structure of the pressure-holding part of the present invention.

[0018] Figure 3 This is a cross-sectional view of the pressure-holding part of the present invention.

[0019] Figure 4 and Figure 5 This is a schematic diagram of the cutter head structure of the present invention.

[0020] Figure 6 This is a schematic diagram of the high-pressure water cutting unit of the present invention.

[0021] Figure 7 This is a schematic diagram of the locking structure of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote elements with the same or similar functions throughout. However, it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the present invention. To better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size. It is understandable for those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present invention.

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0024] The power system and transmission system of this invention are common knowledge in the field and will not be described in detail below.

[0025] This invention provides an in-situ high-fidelity sampling device for layered rock masses, comprising a support platform 1 and a sampling unit. The support platform 1 is provided with a slide rail 4, and the sampling unit is slidably connected to the support platform 1 via the slide rail 4. The sampling unit is hollow inside to accommodate layered rock mass samples 5. The sampling unit includes a detachably connected pressure-holding part 2 and a drilling part 3. The pressure-holding part 2 has a pressure-holding bladder 34 circumferentially arranged on the inner side of its sidewall 31. The pressure-holding bladder 34 is used to apply uniform radial pressure to the layered rock mass sample 5 inside it during the sampling process to simulate the in-situ confining pressure state. The front end of the drilling part 3 is provided with several cutterheads 51 for cutting the rock mass. The cutting edges of the cutterheads 51 face the rock surface. A high-pressure water cutting unit is provided on the inner wall side of the drilling part 3 near the pressure-holding part 2. The high-pressure water cutting unit can cut the rock sample between the drilling part 3 and the pressure-holding part 2 and form a flat cutting surface.

[0026] The bottom of the support platform 1 can be equipped with a height adjustment device, such as a hydraulic support column, and an anti-slip base can be set at the bottom of the hydraulic support column to make horizontal adjustments under different terrain conditions and ensure the accuracy of the drilling direction. The surface of the hydraulic support column can be set with scale lines. The support platform 1 can be set with multiple holes and cable interfaces for installing and fixing the sampling unit, slide rail 4, external power drive equipment, control system, etc. The surface of the support platform 1 can also be set with a horizontal ruler.

[0027] In addition, the supporting multi-functional platform 1 integrates an energy supply module and a liquid circulation system to ensure the continuous and stable operation of the entire sampling device. The energy supply module is typically equipped with a diesel generator set or an external power interface, providing stable power output to the sampling unit's power system, control system, and the drive device of the slide rail 4. The liquid circulation system provides pressure-holding fluid to the pressure-holding bladder 34 and cleaning fluid to the cutterhead 51, ensuring cooling and slag removal during the drilling process. A cleaning fluid delivery pipe can be installed inside the cutterhead 51. During drilling, the cleaning fluid is sprayed out through the nozzles of the cleaning fluid delivery pipe to cool the drill bit and carry away the rock cuttings and debris generated during drilling out of the borehole, keeping the borehole clean and improving drilling efficiency.

[0028] The high-pressure water cutting unit includes a high-pressure water inlet 53 for receiving high-pressure water and a high-pressure water outlet 52 for outputting high-pressure water. Multiple high-pressure water outlets 52 are arranged along the height directions of two opposite inner walls of the drilling section 3.

[0029] The high-pressure water jet cutting unit includes a water flow control valve installed at the outlet and a nozzle fixed at the tail of the control valve.

[0030] The high-pressure water flow delivers a uniform and concentrated impact, avoiding the vibration, torque impact, and resulting damage to the bedding structure that can occur with traditional mechanical cutting methods. After cutting, a smooth cut surface is formed at the root of the rock sample, preserving the bedding structure intact and providing a high-quality sample for subsequent high-fidelity testing. Simultaneously, the drilling structure can be equipped with an intelligent control system to monitor various parameters during the cutting process in real time, such as water pressure and cutting time, to ensure the stability and consistency of the cutting effect. The pressure-holding bladder 34 is a hydraulic bladder with an inflation port 33.

[0031] The flexible hydraulic bladder expands adaptively when hydraulic pressure is applied, closely conforming to rock fissures or bedding planes, thus effectively buffering external disturbances and uniformly transmitting pressure. The outer layer of the hydraulic bladder is made of high-strength, wear-resistant composite material, capable of withstanding friction and compression during sampling; its surface is also designed with a micro-convex textured structure to increase friction when in contact with the rock mass, preventing slippage during sampling; the inner layer is made of rubber material with good flexibility and sealing properties to ensure that the hydraulic bladder expands uniformly and without leakage when pressurized.

[0032] The side wall 31 is axially provided with a pressure sensor 32 for real-time monitoring of pressure changes in the hydraulic bladder. The pressure sensor 32 is nested and adjacent to the pressure-holding bladder 34. The confining pressure of the pressure-holding bladder 34 is dynamically adjusted according to the feedback of the pressure sensor 32 to simulate the in-situ confining pressure state.

[0033] The pressure sensor 32 is connected to the intelligent control module. The pressure sensor 32, which is nested on the hydraulic bladder, provides real-time feedback of the pressure value. The intelligent control module dynamically adjusts the pressure value based on the data fed back by the pressure sensor 32 to simulate the in-situ confining pressure state.

[0034] The pressure sensor 32 uses piezoelectric sensing technology, and the intelligent control module that works closely with it has built-in advanced control algorithms and data processing programs.

[0035] The cutter head 51 includes a main disc 41 and cutter teeth 42, with the cutter teeth 42 facing the rock surface and the surface of the cutter teeth 42 being spherical.

[0036] The slide rail 4 is equipped with a locking structure 21, which is a friction material layer. When the sampling unit retracts, it loses speed. The friction provided by the locking structure 21 can reduce the speed of the sampling unit and prevent safety accidents.

[0037] The slide rail 4 typically employs a combination of high-precision guide rails and sliders, fixed to the supporting multi-functional platform 1 by bolts or welding, providing stable support and sliding guidance for the pressure holding device 2 and the drilling device 3. Simultaneously, the locking structure 21 installed on the slide rail 4 is used to prevent the device from stalling during drilling and sampling, thus avoiding safety accidents.

[0038] The internal cavity of the sampling unit has a rectangular cross-section.

[0039] The pressure-holding bladder 34 has a raised textured surface, thereby increasing the friction between it and the inner layered rock sample 5.

[0040] This invention provides a high-fidelity in-situ sampling method for layered rock masses, comprising the following steps: Step 1: Select the sampling point of the layered rock mass, clean up the pumice, debris and weathered layer around the sampling point, place the support platform 1 flat, assemble the sampling device completely and connect it to the control system; Step 2: After calibrating the drilling direction with the positioning instrument, start the control system to drive the sampling unit forward along the slide rail 4, while the cutter head 51 rotates to cut the rock surface. Step 3: After the initial formation of the layered rock mass sample 5, the pressure-holding bladder 34 is filled with water through the filling port 33 and expands to apply uniform radial pressure to the inner layered rock mass sample 5, simulating the in-situ confining pressure state. The pressure value of the pressure-holding bladder 34 can be preset according to the formation stress and adjusted in real time through the pressure sensor 32 to suppress the volume expansion or microcrack generation of the layered rock mass sample 5 due to stress release. Step 4: After drilling is completed and the internal pressure reaches a stable level, the high-pressure water cutting unit is activated to cut the connection between the five rock samples of the layered rock mass and the bedrock. Step 5: Transfer the pressure-holding section 2 and the layered rock sample 5 inside it to the laboratory for subsequent tests.

[0041] In step one, to ensure that the support platform 1 is placed stably, cement grout or special pads can be used to level and fix the bottom of the device to prevent the equipment from shifting or vibrating during drilling.

[0042] Step 2: Before starting the control system, check and connect the water source, power supply and inert gas supply pipelines to prepare for subsequent drilling, pressure holding and non-destructive transfer. Connect all hydraulic, electrical and data transmission lines, start the control system for no-load testing, and confirm that the sensor feedback, pressure regulation and cutting unit functions normally. Before starting, ensure that the sampling unit is perpendicular to the rock sample surface.

[0043] In step two, an intelligent drilling control system can be set up, with the cutterhead rotating at a low speed and slowly contacting the rock surface. The system uses built-in sensors to monitor torque, thrust, and vibration data in real time, dynamically adjusting the rotation speed and feed pressure to ensure smooth drilling along the direction perpendicular to the bedding planes. During the process, a moderate flow rate of cleaning fluid is maintained to avoid eroding weak interlayers. A pressure-maintaining device is activated during drilling.

[0044] In step three, pressure holding is initiated immediately after the rock sample is initially formed. The hydraulic bladder rapidly inflates with water, applying uniform radial pressure to the outer wall of the rock sample to simulate in-situ confining pressure. This pressure value can be preset according to the formation stress and adjusted in real time via a pressure sensor to suppress volume expansion or microcrack formation caused by stress release in the rock sample.

[0045] In step four, after the rock sample drilling is completed and the pressure reaches a stable state, the high-pressure water jet cutting unit at the bottom of the drilling device is activated. A micro-nozzle sprays high-speed water to precisely cut the junction between the rock sample root and the bedrock. The water jet process is free from mechanical vibration or torque impact, resulting in a smooth cut surface that maximizes the protection of the rock sample's bedding structure and integrity.

[0046] In step five, the connection mechanism between the pressure holding device and the drilling device is disconnected, and the pressure holding device and rock sample are extracted slowly and uniformly. The rock sample is always sealed inside the pressure holding device. After being pulled out of the borehole, it is immediately connected to the inert gas protection system. The rock sample and the pressure holding device are transferred as a whole to a specially made transport box, which is kept under constant temperature and humidity protection until it is delivered to the laboratory for subsequent tests.

[0047] This invention achieves precise and gentle sampling of layered rock masses through a low-speed, low-disturbance drilling device. The system automatically optimizes drilling operations based on real-time feedback of drilling parameters, effectively avoiding shear damage to weak interlayers caused by drill bit vibration and pressure fluctuations, and significantly improving the structural integrity of rock samples, especially layered rock samples.

[0048] This invention, through an innovative in-situ stress-maintaining mechanism, successfully overcomes the technical challenges of stress release and secondary disturbance. Radial constraint stress is applied at the moment of sampling, maximizing the maintenance of the in-situ stress state of the rock sample. The separation characteristics of the pressure-holding device and the bottom cutterhead power unit ensure the overall stability of the rock sample during drilling and transfer, achieving high-fidelity transportation of the rock sample from underground to the laboratory.

[0049] This invention utilizes a built-in high-pressure water flow non-destructive cutting technology to replace the traditional twisting method, eliminating mechanical damage to the root of the rock sample at its source. This technology produces a smooth cut surface without additional disturbance, ensuring the acquisition of test samples that accurately reflect the true mechanical properties of the rock mass, and significantly improving the reliability of test data and its engineering guidance significance.

[0050] This invention achieves intelligent and integrated sampling processes, significantly improving the standardization and efficiency of sampling. The device integrates multiple key functional modules, with a clear and controllable operation process, reducing over-reliance on operator experience and providing advanced equipment support for large-scale, standardized acquisition of high-quality rock samples.

[0051] The sampling method employed in this invention is representative and suitable for in-situ high-fidelity sampling of layered rock masses exhibiting significant anisotropy. This sampling method fully considers the structural characteristics of layered rock masses, effectively avoiding damage to the rock structure through precise borehole positioning and low-disturbance drilling. During drilling, the intelligent control system adjusts drilling parameters in real time to ensure the drill bit drills smoothly along the optimal path and pressure, thereby minimizing shear disturbance to the layered structure and weak interlayers. Simultaneously, the application of an in-situ pressure-holding device successfully simulates the in-situ confining pressure state of the rock sample, preventing volume expansion or crack formation caused by stress release, further ensuring the structural integrity of the rock sample. High-pressure water cutting technology is used to cut the root of the rock sample, achieving non-destructive cutting and avoiding the severe damage to the root structure caused by traditional torsion methods. Finally, through the extraction and transfer of high-fidelity rock samples, seamless and non-destructive transfer of rock samples from the field to the laboratory is ensured, providing high-fidelity rock samples for subsequent precise mechanical tests in the laboratory.

[0052] Based on the description and accompanying drawings of this invention, those skilled in the art can easily manufacture or use the in-situ high-fidelity sampling device and method for layered rock masses of this invention, and can achieve the positive effects described in this invention.

[0053] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. The terms "installed," "set," "equipped with," "connected," "linked," and "sleeve" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral construction; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two mechanisms, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] In the description of this invention, it should be understood that the terms "one end," "the other end," "outer side," "inner side," "horizontal," "end," "length," "outer end," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the mechanism 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 invention. The terms "first" and "second" are also used only for the sake of brevity in description and do not indicate or imply relative importance.

[0055] Furthermore, in practicing the claims of this invention, those skilled in the art can understand and influence variations to the disclosed embodiments through a study of the drawings, the disclosure, and the appended claims. Additionally, in the claims and description, words such as "comprising" and "containing" do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes and modifications made in accordance with the present invention are covered by the scope of the claims of the present invention, and will not be listed here.

Claims

1. A high-fidelity in-situ sampling device for layered rock masses, characterized in that, The system includes a support platform (1) and a sampling unit. The support platform (1) is equipped with a slide rail (4). The sampling unit is slidably connected to the support platform (1) via the slide rail (4). The sampling unit is hollow inside to accommodate layered rock samples (5). The sampling unit includes a detachably connected pressure-holding part (2) and a drilling part (3). The pressure-holding part (2) has a pressure-holding bladder (34) circumferentially arranged on the inner side of the sidewall (31). The pressure-holding bladder (34) is used to apply uniform radial pressure to the layered rock sample (5) inside it during the sampling process to simulate the in-situ confining pressure state. The front end of the drilling part (3) is circumferentially equipped with several cutterheads (51) for cutting the rock. The cutting edge of the cutterhead (51) faces the rock surface. The drilling part (3) is equipped with a high-pressure water cutting unit on the inner wall side of the pressure-holding part (2). The high-pressure water cutting unit can cut the rock sample between the drilling part (3) and the pressure-holding part (2) and form a flat cutting surface.

2. The in-situ high-fidelity sampling device for layered rock masses as described in claim 1, characterized in that, The high-pressure water cutting unit includes a high-pressure water inlet (53) for receiving high-pressure water and a high-pressure water outlet (52) for outputting high-pressure water. Multiple high-pressure water outlets (52) are arranged along the two opposite inner wall height directions of the drilling part (3).

3. The in-situ high-fidelity sampling device for layered rock masses as described in claim 1, characterized in that, The pressure-holding bladder (34) is a hydraulic bladder with an inlet (33).

4. The in-situ high-fidelity sampling device for layered rock masses as described in claim 1, characterized in that, The sidewall (31) is provided with a pressure sensor (32) in the axial direction. The pressure sensor (32) is nested and adjacent to the pressure-holding bladder (34). The confining pressure of the pressure-holding bladder (34) is dynamically adjusted according to the feedback of the pressure sensor (32) to simulate the in-situ confining pressure state.

5. The in-situ high-fidelity sampling device for layered rock masses as described in claim 1, characterized in that, The cutter head (51) includes a main disc (41) and cutter teeth (42), the cutter teeth (42) facing the rock surface, and the surface of the cutter teeth (42) is spherical.

6. The in-situ high-fidelity sampling device for layered rock masses as described in claim 1, characterized in that, The slide rail (4) is provided with a locking structure (21) at its tail end, and the locking structure (21) is a friction material layer.

7. The in-situ high-fidelity sampling device for layered rock masses as described in claim 1, characterized in that, The internal cavity of the sampling unit has a rectangular cross-section.

8. The in-situ high-fidelity sampling device for layered rock masses as described in claim 1, characterized in that, The pressure-retaining bladder (34) has a raised textured surface, thereby increasing the friction between it and the inner layered rock sample (5).

9. A high-fidelity in-situ sampling method for layered rock masses, characterized in that, Includes the following steps: Step 1: Select the sampling point of the layered rock mass, clean up the pumice, debris and weathered layer around the sampling point, place the support platform flat (1), assemble the sampling device completely and connect it to the control system; Step 2: After calibrating the drilling direction with the positioning instrument, start the control system to drive the sampling unit forward along the slide rail (4), while the cutter head (51) rotates to cut the rock surface; Step 3: After the initial formation of the layered rock mass sample (5), the pressure-holding bladder (34) is filled with water through the filling port (33) and expands to apply uniform radial pressure to the inner layered rock mass sample (5) to simulate the in-situ confining pressure state. The pressure value of the pressure-holding bladder (34) can be preset according to the formation stress and adjusted in real time through the pressure sensor (32) to suppress the volume expansion or microcrack generation of the layered rock mass sample (5) due to stress release. Step 4: After drilling is completed and the internal pressure reaches a stable level, the high-pressure water cutting unit is started to cut the root of the layered rock sample (5) at the junction with the bedrock. Step 5: Transfer the pressure-holding section (2) and the layered rock samples (5) inside it to the laboratory for subsequent tests.

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