Core drilling device and process method for pressure-maintained surrounding rock coring

Abstract

The application discloses a coring device and process method for surrounding rock pressure-keeping coring, and belongs to the technical field of geological exploration process equipment design and manufacturing. The coring device and process method can make the rock core keep the original stress state as much as possible. The coring device comprises a sampling, cutting and deslagging assembly, a cushioning and spouting coating system and a pressure-keeping and pressurizing system. In the sampling process of the rock core, the cushioning and spouting coating system and the pressure-keeping and pressurizing system sequentially follow the sequentially progressive order, and the cutting groove cut by the sampling, cutting and deslagging assembly is used to spout the cushioning coating layer to the surface of the cut part of the rock core by means of occupation spouting and occupation pressurizing, and the pressure-keeping stress is applied to the rock core which has been cut and coated with the cushioning coating layer under the cooperation of the surrounding rock on the other side of the cutting groove.

Description

Technical Field

[0001] This invention relates to a coring device, and more particularly to a coring device for pressure-maintaining coring in surrounding rock, belonging to the field of geological exploration process equipment design and manufacturing technology. This invention also provides a process method for obtaining rock cores using the aforementioned coring device for pressure-maintaining coring in surrounding rock. Background Technology

[0002] With the continuous development of human society, underground space has become an important place for human development, and there is a trend towards deeper and larger development. Large underground caverns often suffer from complex geological conditions and massive excavation scale, making them prone to rock instability and posing significant challenges to their construction and operation. Rock stability is closely related to the mechanical properties of rock under different loads, and is crucial for analyzing rock deformation and failure. Previous studies on the mechanical properties of surrounding rock have primarily relied on laboratory rock mechanical property tests, using selected rock blocks that meet the conditions in the field, processing standard rock samples, and conducting related tests. However, the rock blocks selected using existing methods have already detached from the original rock mass and are in an unloaded state, altering the natural stress state of the rock. Even with subsequent application of external loads using relevant testing equipment, it is impossible to completely recreate the deformation and failure characteristics of the original rock during excavation. A further limitation of previous tests is the lack of equipment and methods for core sampling while maintaining the original rock pressure.

[0003] In the process of stress analysis of surrounding rock, the structural state of the surrounding rock, such as natural fissures and faults, is another important influencing factor besides the original stress state of the rock, significantly affecting the deformation and failure characteristics of the surrounding rock under external forces. Maintaining the original structural state of the rock is a crucial prerequisite for revealing the mechanical properties of the surrounding rock in the field during rock mechanics experiments. The previously selected rock blocks have detached from the original rock mass and are in an unloaded state; therefore, the structural state of the rock will change to varying degrees. The reason for this is that the original stress state of the selected rock has changed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a coring device for pressure-maintaining coring of surrounding rock that can maintain the original stress state of the rock core as much as possible, and a process method for obtaining rock cores using the coring device for pressure-maintaining coring of surrounding rock.

[0005] The technical solution adopted to solve the above-mentioned technical problems is: a core sampling device for pressure-maintaining core sampling in surrounding rock. The core sampling device includes a sampling, cutting and deslag removal component, a grouting and coating system, and a load-maintaining and pressurizing system. During the core sampling process, the grouting and coating system and the load-maintaining and pressurizing system follow a progressive sequence, using the method of advancing grouting and advancing pressurizing to spray the grouting and coating layer onto the surface of the cut core through the cutting groove cut by the sampling, cutting and deslag removal component. With the cooperation of the surrounding rock on the other side of the cutting groove, a load-maintaining pressure stress is applied to the cut core covered with the grouting and coating layer.

[0006] Furthermore, the sampling, cutting, and slag removal system includes a high-pressure water jet cutting sampling system and a strong suction output slag removal system. During the core sampling process, the parallel high-pressure water jet cutting sampling system and the strong suction output slag removal system respectively cut sampling trenches on the surrounding rock to collect samples and absorb and remove the rock slag discharged from the sampling and cutting process.

[0007] The preferred embodiment of the above scheme is that the high-pressure water jet cutting sampling system includes a water jet nozzle, a high-pressure cutting hose and a high-pressure cutting pump, with the water jet nozzle arranged at the outlet end of the high-pressure cutting hose and the inlet end of the high-pressure cutting hose connected to the high-pressure cutting pump.

[0008] Furthermore, the strong absorption output slag discharge system includes a horn-shaped suction head, a high-pressure slag removal hose, and a pump suction structure. The horn-shaped suction head is arranged at the suction end of the high-pressure slag removal hose, the input end of the high-pressure slag removal hose is connected to the pump suction structure, the high-pressure cutting hose is arranged in parallel with the high-pressure slag removal hose, and the water jet nozzle extends out in the cross-section and is arranged in parallel with the horn-shaped suction head.

[0009] The preferred embodiment of the above scheme is that the padding shotcrete coating system includes a concrete nozzle, a high-pressure concrete hose and a high-pressure shotcrete pump, with the concrete nozzle arranged at the outlet end of the high-pressure concrete hose and the inlet end of the high-pressure concrete hose connected to the high-pressure shotcrete pump.

[0010] Furthermore, the load-holding and pressurizing system includes a pressure head, a high-pressure load-holding pipeline, and a hydraulic loading component. During and after cutting, the surface of the rock core covered with a padding coating is kept in the compressive stress state before sampling by the load-holding pressure applied by the hydraulic loading component output from the high-pressure load-holding pipeline through the pressure head.

[0011] The preferred method of the above scheme is that the rock core is a regular hexahedron, and a pressure head is installed on each of the five sides cut out of the rock core. Each pressure head applies compressive stress to the corresponding side with the cooperation of the surrounding rock on the other side of the cutting groove.

[0012] Furthermore, the coring device also includes a stress testing system, through which the compressive stress applied to each side of the rock core by the indenter is monitored by the telescopic tube of the stress testing system in conjunction with the strain gauge of the stress testing system.

[0013] The preferred embodiment of the above scheme is that the high-pressure cutting pump, the pump suction structure, the high-pressure shotcrete pump, the hydraulic loading assembly, and the strain gauge are integrated into a single unit.

[0014] The process for obtaining rock cores using the aforementioned coring device for pressure-maintaining coring of surrounding rock includes the following steps: First, the stress parameters of the surrounding rock to be sampled are obtained through geological survey data. Then, the stress parameters are input into the pressure-maintaining system. Next, the high-pressure water jet cutting sampling system, the strong suction output slag removal system, the padding and spraying grouting system, the pressure-maintaining system, and the stress testing system are started to cut, remove slag, spray grouting, and apply stress to each of the four sides and one end face of the rock core individually in a single operation until all five sides are cut while maintaining the original pressure stress.

[0015] The beneficial effects of this invention are as follows: The technical solution provided in this application sets up a core sampling device including a sampling, cutting, and deslag removal component, a grouting and coating system, and a load-bearing and pressurizing system. During the core sampling process, the grouting and coating system and the load-bearing and pressurizing system follow a progressive sequence, using an advancing grouting and pressurizing method to spray a grouting and coating layer onto the cut surface of the core through the cutting groove cut by the sampling, cutting, and deslag removal component. With the cooperation of the surrounding rock on the other side of the cutting groove, the grouting and coating layer is applied to the cut and coated core. The core sample is subjected to a pressure-maintaining stress. The specific process involves first obtaining the stress parameters of the surrounding rock to be sampled from geological data. These parameters are then input into the pressure-maintaining system. Next, the high-pressure water jet cutting sampling system, the strong suction output slag removal system, the grouting and coating system, the pressure-maintaining system, and the stress testing system are activated. Each of the four sides and one end face of the core sample is individually cut, slag removed, grouted, and stress-applied in a single operation until all five sides are cut while maintaining the original pressure stress. In this way, because the sampling seam is cut simultaneously with the slag removal and cutting components, the grouting and coating and pressure-maintaining processes are progressively applied, ensuring that the obtained core sample retains as much of the stress state as possible within the surrounding rock, providing a relatively realistic picture for subsequent experimental analysis. Attached Figure Description

[0016] Figure 1 This is a simplified structural diagram of the coring device for pressure-maintaining coring in surrounding rock according to the present invention.

[0017] The components in the diagram are labeled as follows: 1. Water jet nozzle; 2. High-pressure cutting hose; 3. High-pressure cutting pump; 4. Horn-shaped suction head; 5. High-pressure slag removal hose; 6. Pump suction structure; 7. Concrete nozzle; 8. High-pressure concrete hose; 9. High-pressure shotcrete pump; 10. Pressure head; 11. High-pressure load-bearing pipeline; 12. Hydraulic loading assembly; 13. Telescopic pipe; 14. Strain gauge. Detailed Implementation

[0018] like Figure 1The invention illustrates a coring device for pressure-maintaining coring of surrounding rock cores, which preserves the original stress state of the core as much as possible, and a process method for obtaining cores using the aforementioned coring device. The coring device includes a sampling, cutting, and descaling assembly, a grouting and coating system, and a load-maintaining and pressurizing system. During core sampling, the grouting and coating system and the load-maintaining and pressurizing system sequentially advance, spraying a grouting and pressurizing layer onto the cut surface of the core core through the cutting groove created by the sampling, cutting, and descaling assembly. With the cooperation of the surrounding rock on the other side of the cutting groove, a load-maintaining pressure stress is applied to the cut and coated core core. The technical solution provided in this application involves setting up a core sampling device including a sampling, cutting, and deslag removal component, a grouting and coating system, and a load-holding and pressurizing system. During the core sampling process, the grouting and coating system and the load-holding and pressurizing system follow a progressive sequence, using an advancing grouting and pressurizing method to spray a grouting and coating layer onto the cut surface of the core through the cutting groove created by the sampling, cutting, and deslag removal component. With the cooperation of the surrounding rock on the other side of the cutting groove, a load-holding pressure is applied to the core that has been cut and coated with the grouting and coating layer. The specific process is as follows: first, the stress parameters of the surrounding rock to be sampled are obtained through geological survey data. Then, the stress parameters are input into the load-holding and pressurizing system. Next, the high-pressure water jet cutting and sampling system, the strong suction output deslag removal system, the grouting and coating system, the load-holding and pressurizing system, and the stress testing system are started to cut, deslag, coat with grout, and apply stress to each of the four sides and one end face of the core individually and in one go, until all five sides are cut while maintaining the original pressure stress. In this way, as the sampling seam is cut by the sampling cutting and slag removal component, the padding, spraying, and pressure are carried out simultaneously, so that the obtained rock core sample can retain the stress state in the surrounding rock as much as possible, providing a relatively realistic situation for subsequent test analysis.

[0019] Accordingly, in order to integrate with the actual coring work as much as possible and to simplify the structure of each component of the coring device of this application, so as to facilitate subsequent operation and reduce manufacturing costs, the sampling, cutting and slag removal system of this application includes a high-pressure water jet cutting sampling system and a strong suction output slag removal system. During the core sampling process, the parallel high-pressure water jet cutting sampling system and the strong suction output slag removal system cut sampling trenches on the surrounding rock to collect samples and absorb and remove the rock slag discharged from the sampling and cutting process, respectively. The high-pressure water jet cutting sampling system includes a water jet nozzle 1, a high-pressure cutting hose 2 and a high-pressure cutting pump 3. The water jet nozzle 1 is arranged at the spray end of the high-pressure cutting hose 2, and the input end of the high-pressure cutting hose 2 is connected to the high-pressure cutting pump 3. The strong absorption and output slag removal system includes a trumpet-shaped suction head 4, a high-pressure slag removal hose 5, and a pump suction structure 6. The trumpet-shaped suction head 4 is arranged at the suction end of the high-pressure slag removal hose 5, and the input end of the high-pressure slag removal hose 5 is connected to the pump suction structure 6. The high-pressure cutting hose 2 is arranged in parallel with the high-pressure slag removal hose 5, and the water jet nozzle 1 extends out in the cross-section and is arranged in parallel with the trumpet-shaped suction head 4. The padding and shotcrete coating system includes a concrete nozzle 7, a high-pressure concrete hose 8, and a high-pressure shotcrete pump 9. The concrete nozzle 7 is arranged at the discharge end of the high-pressure concrete hose 8, and the input end of the high-pressure concrete hose 8 is connected to the high-pressure shotcrete pump 9. The load-holding and pressurizing system includes a pressure head 10, a high-pressure load-holding pipeline 11, and a hydraulic loading component 12. During and after cutting, the surface of the rock core covered with the padding and coating layer is maintained in the compressive stress state before sampling by the load-holding pressure applied by the pressure head 10 through the hydraulic loading component 12 output from the high-pressure load-holding pipeline 11.

[0020] Furthermore, considering the hexahedral structure of the rock core, this application installs a pressure head 10 on each of the five sides cut from the rock core. Each pressure head 10, in conjunction with the surrounding rock on the other side of the cutting groove, applies compressive stress to the corresponding side. Simultaneously, to monitor the mechanical properties of the rock core in real time during sampling, the core sampling device described in this application also includes a stress testing system. The compressive stress applied to each side of the rock core by the pressure heads 10 is monitored through the telescopic tube 13 of the stress testing system in conjunction with the strain gauge 14. Furthermore, for structural integration, this application integrates the high-pressure cutting pump 3, the pump suction structure 6, the high-pressure shotcrete pump 9, the hydraulic loading assembly 12, and the strain gauge 14 into a single unit.

[0021] In summary, the technical solution of this application utilizes high-pressure water jet as the power source for the drilling system; provides a slag removal path through a slag removal system; provides a smooth stress surface for applying external loads through a slurry injection system to ensure uniform load distribution; and provides a pressure source for real-time adjustment through a pressurization and load-holding system and a stress testing system. This experimental device and method can effectively complete core sampling of underground engineering rock under the original rock stress state, providing a solid foundation for a more realistic understanding of the mechanical properties of the surrounding rock.

[0022] The technical solution of this application will be further described below through specific embodiments:

[0023] The purpose of this invention is to overcome the shortcomings of existing technologies and develop a device and method for pressure-maintaining core sampling in underground engineering projects. This provides more accurate mechanical test parameters for stability studies of surrounding rock in underground engineering projects, making subsequent research results closer to the actual state of deformation and failure of the surrounding rock. Specifically, it allows for real-time replenishment of stress losses that may occur during drilling, based on the original rock stress state before excavation, ensuring that the original rock stress state remains unchanged. The device and method developed by this invention can more realistically reveal the mechanical properties of the surrounding rock in the field, representing a breakthrough from traditional experimental core sampling methods.

[0024] The technical solution adopted in this application is to provide a device and method for pressure-maintaining coring in underground engineering sites, which can more realistically reveal the mechanical properties of the surrounding rock. The device includes a drilling system (composed of a high-pressure pump, a high-pressure hose, and a high-pressure nozzle that can rotate 90°), a slag removal system (composed of a pump suction system, a high-pressure hose, and a horn-shaped suction head), a stress testing system (composed of strain gauges and strain meters), a slurry injection system (composed of a high-pressure pump, a high-pressure hose, and a nozzle), and a pressurization and load-maintaining system (composed of a hydraulic loading system, a pressurization pipeline, and a pressure head).

[0025] First, the stress state of the original rock in five directions (front, back, left, right, and rear) before drilling in the area to be cored is determined based on on-site testing or numerical simulation. This allows for the determination of the stress values ​​applied by the pressure-holding system for each direction.

[0026] The drilling system described above uses high-pressure water jets provided by a high-pressure pump station to break up the surrounding rock. The rock-breaking pressure of the water jet through the nozzle should be determined by both the strength of the rock and the drilling speed.

[0027] The water jet nozzle can rotate 90° at the joint of the high-pressure hose to cut the surrounding rock in different directions, and the drilling speed is no higher than 1 cm / min.

[0028] The drilling system described above should be able to perform rock-breaking drilling in four directions (up, down, left, and right) in a single operation, and should not drill in multiple directions simultaneously, in order to minimize the probability and extent of confining pressure loss.

[0029] The water jet nozzles should move forward synchronously with the rock-breaking direction. Secondary water jetting should not be used to break the rock in areas where it has already been broken, so as not to interfere with subsequent shotcrete spraying and pressurization processes.

[0030] The aforementioned slag removal system should keep pace with the drilling system to promptly remove the rock cuttings generated during rock breaking.

[0031] The horn-shaped suction head of the slag removal system should have good toughness, strength and sealing performance to ensure full coverage of rock slag and powerful suction.

[0032] The aforementioned slag removal system's trumpet-shaped suction head can suck out the core from its front surface after the core has been cut, sprayed with concrete slurry, and pressurized.

[0033] The pressure of the slurry injected into the system should not be too high to prevent damage to the core sample. The injected slurry should have the characteristics of rapid setting and high strength, and be able to withstand loads quickly.

[0034] The slurry nozzle should lag behind the drilling system nozzle by at least 2 cm in the rock-breaking direction. The concentration and coverage of the slurry should not be affected by the water jet ahead. At different locations, the sum of the slurry thickness and the core thickness should be consistent to provide a smooth and even surface for subsequent surface pressurization.

[0035] The pressure-holding system described above uses a pressure stress value calculated in advance. The applied pressure value is calculated by computer based on the contact area between the pressure head and the surface of the core concrete. Therefore, the applied pressure value is adjusted in real time.

[0036] The pressure head can be assembled from multiple pieces, and its length, width and height should all be smaller than the rock-breaking width of the drilling system so that the pressure head can move and pressurize in the drilling direction, and ensure that when breaking rock behind the core, it can be moved to pressurize it behind the core.

[0037] The aforementioned indenter should be used in conjunction with a stress testing system. The high-precision strain gauges of the stress testing system should be fitted to the outside of the indenter, allowing for real-time measurement of the applied stress value when the indenter applies load to the concrete surface.

[0038] The aforementioned pressurization and load-bearing system should dynamically adjust the pressurization value in real time based on the pressure value measured by the stress testing system and the stress value calculated in the early stage, ensuring that the pressurization value is always consistent with the original rock stress value.

[0039] The drilling system, slag removal system, slurry injection system, pressure holding system, and stress testing system should all be completed in one direction before moving to the next direction, and the processes in the five directions of up, down, left, right, and back should be completed in sequence.

[0040] The aforementioned slag removal system should, after core cutting and loading are completed, use its trumpet-shaped suction cup to adhere to the front surface of the core and slowly suck it out.

[0041] Example 1

[0042] The specific implementation steps for this example are as follows:

[0043] A core sampling area was selected, and the stress values ​​in five directions (front, back, left, right, and rear) of the area were determined through on-site testing or numerical simulation. The core samples obtained using this invention are hexahedral.

[0044] Determine the drilling speed and rock-breaking width of the area to be broken, and set the water jet pressure value for drilling. The drilling speed should not exceed 1 cm / min, and the nozzle should advance synchronously with the drilling direction.

[0045] When the water jet nozzle advances more than 2 cm, the slurry injection system should advance synchronously, and the thickness of the injected slurry should be consistent with the sum of the core thickness to provide a flat and smooth bearing surface for subsequent surface pressurization. The slurry injection speed should be consistent with that of the water jet nozzle.

[0046] Once the surface of the quick-setting, high-strength concrete can bear the load, the pressure-holding system should be applied in a timely manner to prevent stress loss caused by the hollow surface of the core.

[0047] The initial loading pressure of the indenter on the concrete surface is obtained based on the contact area between the indenter and the core concrete surface and the stress value calculated in the previous stage.

[0048] Based on the measured values ​​from the stress testing system, adjust the pressure value to ensure that the pressure value is always consistent with the original rock stress value.

[0049] Following the steps above, cut and hold the core in five directions (up, down, left, right, and back) sequentially. Then, use a horn-shaped suction cup to adhere the core to the front surface and slowly extract the hexahedral core.

[0050] This invention provides a device and method for pressure-controlled core sampling in underground engineering sites. This experimental device and method can effectively complete the core sampling of underground engineering rock under the original rock stress state, and ensure that the structure of the rock core does not change, thus providing a solid foundation for a more realistic understanding of the mechanical properties of the surrounding rock.

[0051] The above description represents the preferred embodiment of the present invention. Any modifications or improvements made in the future using related principles are within the scope of protection of the present invention.

Claims

1. A coring device for pressure-maintaining coring in surrounding rock, characterized in that: The core sampling device includes a sampling, cutting, and deslag removal assembly, a grouting and coating system, and a load-bearing and pressurizing system. During the core sampling process, the grouting and coating system and the load-bearing and pressurizing system follow a progressive sequence, using the advancing grouting and pressurizing methods to spray the grouting and coating layer onto the surface of the cut core through the cutting groove cut by the sampling, cutting, and deslag removal assembly. With the cooperation of the surrounding rock on the other side of the cutting groove, a load-bearing pressure is applied to the cut core covered with the grouting and coating layer.

2. The coring device for pressure-maintaining coring in surrounding rock according to claim 1, characterized in that: The sampling, cutting, and slag removal system includes a high-pressure water jet cutting sampling system and a strong suction output slag removal system. During the core sampling process, the parallel high-pressure water jet cutting sampling system and the strong suction output slag removal system cut sampling trenches on the surrounding rock to collect samples and absorb and remove the rock slag discharged from the sampling and cutting process, respectively.

3. The coring device for pressure-maintaining coring in surrounding rock according to claim 2, characterized in that: The high-pressure water jet cutting sampling system includes a water jet nozzle (1), a high-pressure cutting hose (2) and a high-pressure cutting pump (3). The water jet nozzle (1) is arranged at the outlet end of the high-pressure cutting hose (2), and the inlet end of the high-pressure cutting hose (2) is connected to the high-pressure cutting pump (3).

4. The coring device for pressure-maintaining coring in surrounding rock according to claim 3, characterized in that: The strong absorption output slag discharge system includes a horn-shaped suction head (4), a high-pressure slag removal hose (5), and a pump suction structure (6). The horn-shaped suction head (4) is arranged at the suction end of the high-pressure slag removal hose (5). The input end of the high-pressure slag removal hose (5) is connected to the pump suction structure (6). The high-pressure cutting hose (2) is arranged in parallel with the high-pressure slag removal hose (5). The water jet nozzle (1) extends out in the cross-section and is arranged in parallel with the horn-shaped suction head (4).

5. The coring device for pressure-maintaining coring in surrounding rock according to claim 1, 2, 3 or 4, characterized in that: The padding shotcrete coating system includes a concrete nozzle (7), a high-pressure concrete hose (8), and a high-pressure shotcrete pump (9). The concrete nozzle (7) is located at the outlet end of the high-pressure concrete hose (8), and the inlet end of the high-pressure concrete hose (8) is connected to the high-pressure shotcrete pump (9).

6. The coring device for pressure-maintaining coring in surrounding rock according to claim 5, characterized in that: The load-holding and pressurizing system includes a pressure head (10), a high-pressure load-holding pipeline (11), and a hydraulic loading component (12). During and after cutting, the surface of the rock core covered with a padding coating is kept under the compressive stress state before sampling by the load-holding pressure applied by the pressure head (10) through the hydraulic loading component (12) output from the high-pressure load-holding pipeline (11).

7. The coring device for pressure-maintaining coring in surrounding rock according to claim 6, characterized in that: The core is a regular hexahedron. A pressure head (10) is installed on each of the five sides cut out of the core. Each pressure head (10) applies compressive stress to the corresponding side with the cooperation of the surrounding rock on the other side of the cutting groove.

8. The coring device for pressure-maintaining coring in surrounding rock according to claim 7, characterized in that: The core sampling device also includes a stress testing system. The compressive stress applied to each side of the core by the pressure head (10) is monitored by the expansion tube (13) of the stress testing system in conjunction with the strain gauge (14) of the stress testing system.

9. The coring device for pressure-maintaining coring in surrounding rock according to claim 8, characterized in that: The high-pressure cutting pump (3), the pump suction structure (6), the high-pressure shotcrete pump (9), the hydraulic loading assembly (12) and the strain gauge (14) are integrated into one unit.

10. A process method for obtaining rock cores using the coring device for pressure-maintaining coring of surrounding rock as described in claim 9, characterized in that: The process includes the following steps: First, obtain the stress parameters of the surrounding rock to be sampled through geological survey data. Then, input the stress parameters into the load-holding and pressurizing system. Next, start the high-pressure water jet cutting and sampling system, the strong suction output slag removal system, the padding and spraying grouting system, the load-holding and pressurizing system, and the stress testing system to independently cut, remove slag, spray grouting, and apply stress to each of the four sides and one end face of the rock core in one go, until all five sides are cut while maintaining the original stress.

Images