Device for measuring hardness of in-situ drilled rock based on high-pressure water pressure head
By using a high-pressure water pressure head device to perform in-situ borehole rock hardness testing, the problems of sampling disturbance and poor data representativeness in rock hardness testing have been solved, enabling rapid and accurate rock strength measurement, which is suitable for downhole operations in complex geological environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHENGZHOU INSTITUTE OF ADVANCED STUDIES HENAN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2025-05-12
- Publication Date
- 2026-04-17
AI Technical Summary
Existing rock hardness testing methods suffer from problems such as sampling disturbance, high cost, long cycle, poor data representativeness, and insufficient testing accuracy. In particular, it is difficult to achieve rapid and accurate in-situ testing in complex geological environments.
A device based on a high-pressure water head, combined with a hydraulic power system, a data acquisition system, and a test probe, is used to conduct in-situ tests inside the borehole. Water is used as the pressure medium to monitor the displacement and pressure of the rock in real time, plot displacement-pressure curves, and obtain rock strength data.
It enables rapid and accurate acquisition of rock strength data without disturbing rock properties, adapts to complex geological environments, reduces costs, improves testing efficiency, reflects the true distribution of rock strength, and is suitable for downhole operating environments.
Smart Images
Figure CN224137022U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of mining engineering technology, specifically relating to a device for measuring the hardness of in-situ drilled rocks based on a high-pressure water pressure head. Background Technology
[0002] In-situ rock hardness testing has wide applications in mining engineering, tunnel engineering, geological disaster prevention and control, underground space development, and water conservancy and nuclear waste engineering. In mining engineering, in-situ testing can provide a basis for tunnel support design, accurately assess the stability of the roof and walls, and prevent accidents such as collapses. In tunnel engineering, by rapidly obtaining information on the hardness of the surrounding rock, excavation techniques and support parameter configurations can be optimized to ensure the safety of construction and the long-term stability of the tunnel structure. In the field of geological disaster prevention and control, in-situ test data can be used to assess the risks of geological disasters such as landslides and collapses and to formulate prevention and control measures. In the process of underground space development, accurately understanding the mechanical properties of rock strata is helpful for the design of deep excavation and the planning and construction of underground engineering projects such as energy storage facilities. In water conservancy and nuclear waste engineering, in-situ testing can effectively assess the stability of rock mass foundations and ensure the safe operation of large-scale engineering facilities. Through in-situ rock hardness testing, real and reliable mechanical parameters can be provided for various geotechnical engineering projects, significantly improving the scientific nature of engineering design and construction safety, and has important engineering application value and social significance.
[0003] In-situ rock hardness testing allows for the measurement of rock's engineering mechanical properties without disturbing the existing rock strata. This avoids the impact of stress release during sampling and offers a wide testing range with strong representativeness. Furthermore, the basic parameters obtained through in-situ testing are highly representative and reflect the actual conditions on-site, such as the rock's compressive strength, tensile strength, and shear strength. These parameters provide a basis for engineering design and also help predict rock mass stability and geological hazard risks, thus contributing to public safety and sustainable development. Therefore, in-situ rock hardness testing technology is of great significance and can be applied in a wide range of applications.
[0004] Currently, rock hardness is primarily determined through laboratory tests, which involve drilling rock cores, processing standard specimens, and conducting compression, tensile, or shear tests under laboratory conditions. However, this traditional testing method has the following problems:
[0005] (1) The core sampling process may cause disturbance to the rock structure, resulting in test results deviating from the actual mechanical properties in situ;
[0006] (2) Core processing and testing have long cycles and high costs, making it difficult to achieve large-scale and rapid evaluation;
[0007] (3) It is difficult to obtain complete rock cores in loose and fractured strata, which seriously affects the representativeness of the data;
[0008] (4) The data points obtained from the experiment are limited and cannot fully reflect the spatial variation characteristics of the hardness of the surrounding rock.
[0009] In addition, existing in-situ testing methods, such as acoustic detection, drilling parameter method, and impact rebound method, are limited by problems such as testing accuracy, large susceptibility to environmental interference, or narrow applicable aperture range of the equipment, making it difficult to meet the actual needs of rapid and accurate in-situ testing of rock hardness in coal mines and other complex geological environments. Utility Model Content
[0010] The purpose of this invention is to provide a device for measuring the hardness of in-situ drilled rocks based on a high-pressure water pressure head, which is suitable for small boreholes, easy to operate, applicable to a wide range of environments, and provides high accuracy in test data.
[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a device for measuring the hardness of in-situ drilled rock based on a high-pressure water head, comprising a hydraulic power system, a data acquisition system, a test probe, and a push rod; the front end of the push rod is connected to the rear end of the test probe;
[0012] The hydraulic power system includes a manual hydraulic piston pump, which is connected to the test probe via a directional three-way valve;
[0013] The data acquisition system includes a data logger, a displacement sensor, and a pressure sensor. The displacement sensor and the pressure sensor are both mounted on the manual hydraulic piston pump and are connected to the data logger via a signal receiver.
[0014] The manual hydraulic plunger pump includes a horizontally positioned base plate. A bearing housing is located on the left side of the base plate, and a horizontally positioned rotating shaft is rotatably connected to the bearing housing via a pressure bearing and a ball bearing. A rotating handle is located at the left end of the rotating shaft. A fixed seat is located on the right side of the base plate, and the pump body is mounted on the fixed seat. A guide rod parallel to the rotating shaft is located between the fixed seat and the bearing housing. A lead screw is coaxially mounted on the right end of the rotating shaft, and a nut is threaded onto the lead screw. A rotation-limiting slider, which is slidably connected to the guide rod, is fixedly connected to the outer circle of the nut. A hollow rod is connected to the right end of the nut, and the lead screw extends coaxially into the hollow rod. A plunger is coaxially mounted on the right end of the hollow rod, extending into the pump body. A sealing ring assembly, which is slidably sealed to the outer circle of the plunger, is located on the inner wall of the left side of the pump body. A water injection hole is located at the top of the pump body, and a sealing stud is located inside the water injection hole. A pressure testing port is located at the right end of the pump body, and a water outlet is located at the bottom of the pump body. The water outlet is connected to the first interface of a reversing three-way valve. A displacement sensor is located on the rotation-limiting slider, and a pressure sensor is installed at the pressure testing port at the right end of the pump body.
[0015] The test probe includes a probe body with a spherical guide head at the front end. The rear end of the probe body is equipped with a threaded connector, a high-pressure inlet, and a low-pressure inlet. The front end of the push rod is connected to the probe body via the threaded connector. A blind hole is provided radially inside the probe body, and a piston is provided at the bottom of the blind hole. A first sealing ring is provided between the outer circle of the piston and the inner circle of the blind hole. A guide cover is threadedly connected to the outer end of the blind hole, and a second sealing ring is provided between the outer circle of the guide cover and the inner circle of the blind hole. A guide hole is provided in the center of the guide cover. A pressure rod is coaxially provided at the outer end of the piston and extends into the guide hole. A pressure head is threadedly connected to the outer end of the pressure rod. A copper sleeve is provided between the inner circle of the guide hole and the outer circle of the pressure rod. The high-pressure inlet is connected to the bottom of the blind hole via a high-pressure water channel, and the low-pressure inlet is connected to the blind hole between the guide cover and the piston via a low-pressure water channel.
[0016] The hydraulic pipeline includes a high-pressure water pipe and a low-pressure water pipe. One end of the high-pressure water pipe is connected to the second port of the reversing three-way valve, and the other end of the high-pressure water pipe is connected to the high-pressure water inlet. One end of the low-pressure water pipe is connected to the third port of the reversing three-way valve, and the other end of the low-pressure water pipe is connected to the low-pressure water inlet.
[0017] By adopting the above technical solution, this utility model enables rapid in-situ testing of roadway surrounding rock through simple operations. Furthermore, by integrating data from real-time monitoring by displacement and pressure sensors, it can plot real-time displacement-pressure curves during the data acquisition process, providing a more detailed understanding of the rock strength testing process. It has the following advantages:
[0018] (1) The testing equipment of this utility model is lightweight and can be taken directly to the site. No sampling is required during the testing process, which can avoid the influence of sampling on the properties of the rock and realize the in-situ testing method of rock strength in the borehole, thus ensuring the original state of the rock.
[0019] (2) It is suitable for the needs of the underground working environment. The density of measuring points can be adjusted according to the site conditions to test the strength of the surrounding rock of a large area of roadway, which can better reflect the real situation on site.
[0020] (3) The test can be carried out continuously, and a large area test can be carried out on multiple holes.
[0021] (4) The testing method has the advantages of being fast and economical. It reduces the process and cost of drilling downhole to obtain rock cores and then bringing them back to the laboratory for uniaxial compressive strength testing, and shortens the testing cycle.
[0022] (5) It can test the strength of surrounding rock under different lithology, water content, confining pressure and water pressure conditions. The probe body is equipped with a pad on the back of the blind hole to increase the diameter of the test probe to meet the needs of drilling holes of various sizes, thereby increasing the applicability of the test device; the material is made of high-strength alloy, especially the pressure head, to ensure that it does not deform under high load and improve the service life of the test equipment.
[0023] (6) It can test data at different depths and points in a single borehole; the test probe is miniaturized and can test boreholes of different sizes by adding pads on the back, making it highly adaptable.
[0024] (7) The measured results include the borehole depth, the strength of the rock wall at that depth, and the ejection displacement of the jack. These results can be displayed on the measuring instrument screen in real time, and the measured data can be stored, recorded, exported, played back, and classified for management.
[0025] (8) The testing process is simple and convenient with low learning costs. A constant volume of pressure medium (water) is injected into the blind hole of the test probe by a plunger-type hydraulic pump. The displacement sensor measures the displacement of the plunger in the plunger-type hydraulic pump and converts it into the displacement of the pressure head.
[0026] (9) Water is used as the pressure medium. Adding and draining water in the system before and after testing is convenient and does not pollute the on-site environment. The water can be taken from the on-site clean water pipeline without the need for special carrying or transportation. It has the advantages of being green, environmentally friendly and pollution-free, not wasting resources, having lightweight equipment, and being economical.
[0027] (10) The test probe and the plunger hydraulic pump are connected by two hydraulic lines (high pressure water pipe and low pressure water pipe). The high pressure water pipe and the low pressure water pipe are connected to the pump body through a three-way valve that can switch directions. The plunger hydraulic pump is equipped with a pressure sensor and a displacement sensor, which can collect data in real time during the loading process.
[0028] In summary, this invention utilizes the principle of penetration testing, drilling holes in the rock mass to be tested or directly using pressure relief and drilling engineering holes, and inserting a test probe deep into the borehole for testing. This invention allows for in-situ on-site mechanical property testing of roof rock strata in coal mines. Compared to traditional laboratory experiments, in-situ testing considers factors such as the natural stress state, water content, temperature, and geological structure of the rock, thus better reflecting the in-situ rock strength. This invention possesses strong durability and environmental adaptability, high testing accuracy, and employs a pressure head displacement measurement method to form a complete set of equipment for in-situ rock strength testing within boreholes. It enables real-time in-situ acquisition of rock strength underground, adapting to the needs of underground working environments. The testing device has a simple structure, is easy to operate, and the test data better reflects the in-situ rock strength. It can measure the rock strength at different boreholes, depths, and locations, thus revealing the distribution of rock strength in the tunnel. The measurement results closely approximate the actual rock mass. Utilizing water as a medium for pressure transmission, the measurement process is simple, convenient, environmentally friendly, and safe, avoiding errors that may occur during sampling and processing. This significantly improves measurement efficiency, reduces costs, addresses the limitations of traditional methods, and promotes intelligent mining. It has significant potential for widespread application. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0030] Figure 2 yes Figure 1 Axial sectional view of a medium hydraulic power system;
[0031] Figure 3 yes Figure 1 Axial cross-sectional view of the test probe;
[0032] Figure 4 yes Figure 1 Exploded view of the test probe. Detailed Implementation
[0033] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples.
[0034] like Figures 1-4 As shown, the device for measuring the hardness of in-situ drilled rock based on a high-pressure water head of this utility model includes a hydraulic power system, a data acquisition system, a test probe 2, and a push rod 1; the front end of the push rod 1 is connected to the rear end of the test probe 2.
[0035] The hydraulic power system includes a manual hydraulic piston pump 3, which is connected to the test probe 2 via a reversing three-way valve 21.
[0036] The data acquisition system includes a data logger 22, a displacement sensor 23, and a pressure sensor 24. The displacement sensor 23 is mounted on the rotation limit slider 14, and the pressure sensor 24 is mounted on the pressure measuring port 19 at the right end of the pump body 10. Both the displacement sensor 23 and the pressure sensor 24 are connected to the data logger 22 through a signal receiver.
[0037] The manual hydraulic plunger pump includes a horizontally positioned base plate 4. A bearing seat 5 is located on the left side of the base plate 4. A horizontally positioned rotating shaft 7 is rotatably connected to the bearing seat 5 via a pressure bearing 6 and a ball bearing 7. A rotating handle 8 is located at the left end of the rotating shaft 7. A fixed seat 9 is located on the right side of the base plate 4, and a pump body 10 is mounted on the fixed seat 9. A guide rod 11, parallel to the rotating shaft 7, is located between the fixed seat 9 and the bearing seat 5. A lead screw 12 is coaxially mounted on the right end of the rotating shaft 7, and a nut 13 is threaded onto the lead screw 12. The outer circumference of the nut 13 is fixedly connected to a sliding element that slides with the guide rod 11. The connecting limit slider 14 and the nut 13 are connected to a hollow rod 15 at the right end. The lead screw 12 extends coaxially into the hollow rod 15. A plunger 16 is coaxially provided at the right end of the hollow rod 15. The plunger 16 extends into the pump body 10. A sealing ring assembly 17 is provided on the left inner wall of the pump body 10 and is slidably sealed to the outer circle of the plunger 16. A water injection hole 18 is provided at the top of the pump body 10. A sealing stud is provided in the water injection hole 18. A pressure test port 19 is provided at the right end of the pump body 10. A water outlet 20 is provided at the bottom of the pump body 10. A reversing three-way valve 21 is connected to the water outlet 20.
[0038] The test probe 2 includes a probe body 25. The front end of the probe body 25 is a spherical guide head 26. The rear end of the probe body 25 is provided with a threaded connector 27, a high-pressure water inlet 28, and a low-pressure water inlet 29. The front end of the push rod 1 is connected to the probe body 25 through the threaded connector 27. A blind hole 30 is provided radially inside the probe body 25. A piston 31 is provided at the bottom of the blind hole 30. A first sealing ring 32 is provided between the outer circle of the piston 31 and the inner circle of the blind hole 30. A guide cover 3 is threadedly connected to the outer port of the blind hole 30. 3. The outer circle of the guide cover 33 is provided with a second sealing ring 34 between the outer circle and the inner circle of the blind hole 30. The guide cover 33 has a guide hole in the center. The outer end of the piston 31 is provided with a pressure rod 35 that extends into the guide hole in the same direction. The pressure head 41 is threaded to the outer end of the pressure rod 35. A copper sleeve 36 is provided between the inner circle of the guide hole and the outer circle of the pressure rod 35. The high pressure water inlet 28 is connected to the bottom of the blind hole 30 through the high pressure water channel 39. The low pressure water inlet 29 is connected to the blind hole 30 between the guide cover 33 and the piston 31 through the low pressure water channel 40.
[0039] The hydraulic pipeline includes a high-pressure water pipe 37 and a low-pressure water pipe 38. One end of the high-pressure water pipe 37 is connected to the second port of the reversing three-way valve 21, and the other end of the high-pressure water pipe 37 is connected to the high-pressure water inlet 28. One end of the low-pressure water pipe 38 is connected to the third port of the reversing three-way valve 21, and the other end of the low-pressure water pipe 38 is connected to the low-pressure water inlet 29.
[0040] The method for testing rock hardness using this invention specifically includes the following steps:
[0041] (1) Connect the hydraulic power system 3 to the data acquisition system: install the displacement sensor 23 on the rotation limit slider 14, install the pressure sensor 24 on the pressure measuring port 19, and then use a data cable to connect the displacement sensor 23 and the pressure sensor 24 to the data recorder 22 respectively.
[0042] (2) Connect the hydraulic power system 3 to the test probe 2 through the hydraulic pipeline: connect one end of the high pressure water pipe 37 to the second port of the reversing three-way valve 21, then connect the other end of the high pressure water pipe 37 to the high pressure water inlet 28, then connect one end of the low pressure water pipe 38 to the third port of the reversing three-way valve 21, and finally connect the other end of the low pressure water pipe 38 to the low pressure water inlet 29.
[0043] (3) Connect the front end of the push rod 1 to the rear end of the test probe 2: The threaded connector 27 is welded to the rear end face of the probe body 25, and the front end of the push rod 1 extends into and is threadedly connected to the threaded connector 27.
[0044] (4) Control the push rod 1 to push the test probe 2 into the borehole: Extend the test probe 2 into the borehole opening, control the push rod 1 to push the test probe 2 into the borehole, and the depth of pushing into the borehole can be obtained by the length of the push rod 1.
[0045] (5) First, fill the pump body 10 of the hydraulic pipeline and hydraulic power system 3 with water; then, rotate the handle 8 by hand. The rotating shaft 7 drives the lead screw 12 to rotate. The nut 13, which is threaded to the lead screw 12, can only move to the right along the length of the lead screw 12 under the limitation of the rotation limit slider 14. The rotation limit slider 14 also moves to the right with the limit block. The nut 13 drives the hollow rod 15 and the plunger 16 to move to the right. The plunger 16 drives the water in the pump body 10 to pass through the reversing three-way valve 21 and the high-pressure water pipe 37 in sequence. High-pressure water is injected into the blind hole 30 through the high-pressure inlet 28 and high-pressure water channel. The high-pressure water pushes the piston 31 to move outward. The piston 31 drives the pressure rod 35 and the pressure head 41 to move outward along the guide cover 33. The pressure head 41 presses against the borehole wall. The handle 8 is rotated at a constant speed, and the high-pressure water enters the blind hole 30 at a constant speed, driving the pressure head 41 to pressurize the borehole wall at a constant speed until the rock wall is fractured under the action of the pressure head 41. At this time, the pressure value monitored by the pressure sensor 24 shows a sudden drop. The peak pressure in this process is the critical load when the rock breaks. Then, the reversing three-way valve 21 is operated to reverse the flow. The first and third ports of the three-way valve 21 are connected, while the high-pressure water pipe 37 is separated from the second port of the reversing three-way valve 21. The handle 8 is rotated to push the plunger 16 to press the water in the pump body 10 into the low-pressure water pipe 38, and then into the blind hole 30 between the guide cover 33 and the piston 31 through the low-pressure water channel. The low-pressure water drives the piston 31 to return to the bottom of the blind hole 30, and the water in the blind hole 30 is forced out of the high-pressure water pipe 37. The pressure head 41 retracts back into the blind hole 30. Then, the push rod 1 is rotated or moved to move the test probe 2 to the next depth for the next rock hardness test.
[0046] It should be emphasized that the manual hydraulic piston pump, data logger, signal receiver, displacement sensor, and pressure sensor in this utility model are all conventional equipment or components, readily available on the market; therefore, their specific structures and working principles will not be elaborated upon. Furthermore, the data calculation and conversion involved in this utility model are also conventional technical methods, and do not involve any new computer programs.
[0047] The above embodiments illustrate the basic principles and features of this utility model. However, the above descriptions are merely preferred embodiments and are not limited to these embodiments. Those skilled in the art, inspired by this patent, can make many modifications and improvements without departing from the spirit and scope of the claims, all of which fall within the protection scope of this utility model. Therefore, the patent and its scope of protection should be determined by the appended claims.
Claims
1. A device for measuring the hardness of rock in situ in a borehole based on a high pressure water head, characterised in that: Includes a hydraulic power system, a data acquisition system, a test probe, and a push rod; the front end of the push rod is connected to the rear end of the test probe; The hydraulic power system includes a manual hydraulic piston pump, which is connected to the test probe via a directional three-way valve; The data acquisition system includes a data logger, a displacement sensor, and a pressure sensor. The displacement sensor and the pressure sensor are both mounted on the manual hydraulic piston pump and are connected to the data logger via a signal receiver.
2. The device for measuring the hardness of rock in a borehole in situ based on the high-pressure water head according to claim 1, characterized in that: The manual hydraulic plunger pump includes a horizontally positioned base plate. A bearing housing is located on the left side of the base plate, and a horizontally positioned rotating shaft is rotatably connected to the bearing housing via a pressure bearing and a ball bearing. A rotating handle is located at the left end of the rotating shaft. A fixed seat is located on the right side of the base plate, and the pump body is mounted on the fixed seat. A guide rod parallel to the rotating shaft is located between the fixed seat and the bearing housing. A lead screw is coaxially mounted on the right end of the rotating shaft, and a nut is threaded onto the lead screw. A rotation-limiting slider, which is slidably connected to the guide rod, is fixedly connected to the outer circle of the nut. A hollow rod is connected to the right end of the nut, and the lead screw extends coaxially into the hollow rod. A plunger is coaxially mounted on the right end of the hollow rod, extending into the pump body. A sealing ring assembly, which is slidably sealed to the outer circle of the plunger, is located on the inner wall of the left side of the pump body. A water injection hole is located at the top of the pump body, and a sealing stud is located inside the water injection hole. A pressure testing port is located at the right end of the pump body, and a water outlet is located at the bottom of the pump body. The water outlet is connected to the first interface of a reversing three-way valve. A displacement sensor is located on the rotation-limiting slider, and a pressure sensor is installed at the pressure testing port at the right end of the pump body.
3. The device for measuring the hardness of rock in a borehole in situ based on the high-pressure water head according to claim 2, characterized in that: The test probe includes a probe body with a spherical guide head at the front end. The rear end of the probe body is equipped with a threaded connector, a high-pressure inlet, and a low-pressure inlet. The front end of the push rod is connected to the probe body via the threaded connector. A blind hole is provided radially inside the probe body, and a piston is provided at the bottom of the blind hole. A first sealing ring is provided between the outer circle of the piston and the inner circle of the blind hole. A guide cover is threadedly connected to the outer end of the blind hole, and a second sealing ring is provided between the outer circle of the guide cover and the inner circle of the blind hole. A guide hole is provided in the center of the guide cover. A pressure rod is coaxially provided at the outer end of the piston and extends into the guide hole. A pressure head is threadedly connected to the outer end of the pressure rod. A copper sleeve is provided between the inner circle of the guide hole and the outer circle of the pressure rod. The high-pressure inlet is connected to the bottom of the blind hole via a high-pressure water channel, and the low-pressure inlet is connected to the blind hole between the guide cover and the piston via a low-pressure water channel.
4. The device for measuring the hardness of rock in a borehole in situ based on the high-pressure water head according to claim 3, characterized in that: The hydraulic pipeline includes a high-pressure water pipe and a low-pressure water pipe. One end of the high-pressure water pipe is connected to the second port of the reversing three-way valve, and the other end of the high-pressure water pipe is connected to the high-pressure water inlet. One end of the low-pressure water pipe is connected to the third port of the reversing three-way valve, and the other end of the low-pressure water pipe is connected to the low-pressure water inlet.