Geotechnical engineering investigation drilling sampling method adaptive to different rock stratums

Abstract

The invention relates to the technical field of geotechnical engineering investigation sampling, in particular to a geotechnical engineering investigation drilling sampling method adaptive to different rock stratums, which comprises the following steps: acquiring rock stratum hardness, feeding depth and sampling scraper pressure data in real time through an indentation hardness sensor, a displacement sensor and a pressure sensor; the MCU unit compares preset threshold values to judge the types of soft rocks, medium hard rocks and hard rocks, dynamically adjusts the rotating speed of the servo adjustable-speed motor, the thrust of the micro electric push rod and the feeding speed of the variable-frequency feeding motor, and can respond to rock stratum mutation within 0.2 s; meanwhile, the sampling precision is guaranteed through cooperative action of the scraping blades, pressure closed-loop control, linear speed reduction and brake locking, sampling data are automatically recorded, and parameters are optimized after multiple times of sampling of the same type of rock stratums. The method is high in rock stratum adaptability, stable in sample quality and high in automation degree, has self-optimization capacity, can be modified based on an existing device, and is convenient to popularize and apply.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering exploration and sampling technology, specifically relating to a drilling and sampling method for geotechnical engineering exploration that is adapted to different rock strata. Background Technology

[0002] In the field of geotechnical engineering investigation, drilling and sampling is a crucial means of obtaining the physical and mechanical parameters of underground rock strata, and its technological development directly affects the reliability of engineering designs. Currently, there are various technical solutions for soil and rock sampling, including: Existing patent document 1 (publication number: CN117948138B) discloses an electric drilling sampling device for geotechnical engineering investigation. Drilling is achieved through the cooperation of a drill rod, sampling rod, drill bit, and drive mechanism, with sensors assisting sampling. Core parameters such as motor speed and feed rate for drilling and sampling must be manually preset and remain fixed throughout the process. This solution fails to differentiate the physical characteristics (such as hardness, integrity, and compressive strength) of soft, medium-hard, and hard rock, uniformly using a single parameter for drilling. For soft rock (hardness ≤ 15MPa), the fixed high thrust easily causes the sampling scraper to crush the sample, damaging its original structure; for hard rock (hardness > 30MPa), the fixed low speed cannot provide sufficient cutting force, resulting in low sampling efficiency. The gripping sampling method in patent CN108827698B also suffers from similar problems. Its clamping force and cutting speed are preset fixed values ​​and cannot be dynamically adjusted according to the hardness of the rock core, making soft rock easily crushed and hard rock easily detached. Determining the type of rock strata requires judging the type of rock strata by the appearance of the sample after sampling is completed. When encountering abrupt changes in rock strata during drilling (such as hard rock blocks appearing in soft rock interlayers, or soft rock with fissures in hard rock strata), the above technology cannot identify them in real time and continues to operate according to the original parameters, resulting in two consequences: First, when hard rock changes abruptly, a fixed low thrust cannot cut in, causing drill bit wear or drill rod jamming; second, when soft rock changes abruptly, a fixed high rotation speed will cause excessive disturbance to the sample, making it lose its representativeness.

[0003] Existing patent document 2 (publication number: CN108827698B) discloses a rock and soil sampling device based on a gripping structure, which collects rock cores through mechanical clamping. Sampling depth control requires manual observation of displacement sensor readings and manual triggering of the stop mechanism, which is prone to depth deviations (often exceeding ±2cm) due to reaction delays. Pressure adjustment of the sampling scraper relies on manual valve turning; differences in force applied by different operators result in sampling pressure fluctuations of ±10N within the same rock stratum, with soft rock samples experiencing disturbance rates exceeding 20%. Furthermore, the clamping action requires manual control of the opening and closing timing; when sampling hard rock, insufficient clamping force leads to a sample detachment probability exceeding 30%, necessitating repeated operations. There is a lack of analysis on the correlation between sample quality and clamping parameters. Therefore, even with multiple samplings in the same area, it is impossible to optimize parameters based on historical data; each operation requires trial and error, resulting in low efficiency and the inability to develop a dedicated sampling plan for specific rock strata in a particular area.

[0004] In summary, while existing technologies have achieved basic drilling and sampling functions, their limitations—such as fixed parameters, delayed rock strata identification, high reliance on manual intervention, and lack of self-optimization—make them ill-suited to the complex and ever-changing underground rock strata environment, resulting in low sampling efficiency and unstable sample quality. In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] To address the aforementioned technical problems in existing technologies, this invention provides a geotechnical engineering exploration drilling and sampling method adapted to different rock strata. This method solves the core problems in sampling techniques, such as fixed sampling parameters that cannot dynamically adapt to different rock strata characteristics, lack of real-time identification and emergency parameter adjustment capabilities for sudden changes in rock strata that easily lead to mechanical failures, inaccurate sampling depth control and poor coordination of component movements resulting in large depth deviations and low sampling efficiency, and excessive manual intervention and low automation that easily affect sampling stability due to operational errors.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A drilling and sampling method for geotechnical engineering exploration adapted to different rock strata is implemented based on a drilling and sampling device for geotechnical engineering exploration. The drilling and sampling device includes a drill rod, a sampling rod, a drill bit, an isolation ring, a sampling scraper, a motor housing, and a telescopic rod. The device is equipped with an indentation hardness sensor, a displacement sensor, a pressure sensor, a servo-controlled variable speed motor with adjustable rotation speed, a miniature electric push rod with adjustable thrust, a variable frequency feed motor with adjustable feed speed, and an MCU unit for data processing. The steps include: S1. Input the adaptation parameter thresholds for different rock layers to the MCU unit through the host computer, and at the same time preset the target sampling depth and feed speed trigger conditions. S2. Start the variable frequency feed motor to drive the drill rod, sampling rod and drill bit to move down and rotate synchronously for drilling. Each sensor collects rock hardness data, feed depth data and sampling scraper pressure data in real time and transmits them to the MCU unit. S3. The MCU unit compares the received rock hardness data with the rock threshold preset in step S1 to determine the type of rock currently being drilled, and then outputs control signals to adjust the speed of the servo adjustable motor, the thrust of the micro electric push rod, and the feed speed of the variable frequency feed motor; if a sudden change in rock characteristics is detected, the MCU unit urgently adjusts the parameters of each actuator. S4. The displacement sensor provides real-time feedback of the feed depth data. When the depth reaches the feed speed trigger condition, the MCU unit controls the variable frequency feed motor to slow down. When the depth reaches the target sampling depth, the variable frequency feed motor stops driving. Subsequently, the MCU unit controls the blocking ring to release the obstruction of the sampling port on the sampling rod surface, drives the sampling scraper to extend from the sampling port, and controls the sampling scraper to reciprocate in the vertical direction, while controlling the sampling rod to rotate at a low speed. S5. After sampling is completed, the MCU unit controls the sampling scraper to retract into the sampling rod, the blocking ring to reset and block the sampling port, and then controls the variable frequency feed motor to run in reverse to drive the drill rod and sampling rod to move to the ground. After the sample is taken out, the MCU unit records the sampling data and automatically corrects the adaptation parameter threshold for the next sampling based on the sample quality.

[0007] Furthermore, the specific threshold values ​​for the adaptation parameters of the different rock strata are as follows: Soft rock adaptation parameters: servo adjustable speed motor speed 1800rpm±50rpm, micro electric push rod thrust 30N±5N, variable frequency feed motor drive drill rod downward movement speed 8mm / s±0.5mm / s; Medium-hard rock adaptation parameters: servo adjustable speed motor speed 1500rpm±50rpm, micro electric push rod thrust 50N±5N, variable frequency feed motor drive drill rod downward movement speed 5mm / s±0.5mm / s; Hard rock adaptation parameters: servo adjustable speed motor speed 1200rpm±50rpm, micro electric push rod thrust 80N±5N, variable frequency feed motor drive drill rod downward movement speed 3mm / s±0.5mm / s.

[0008] Furthermore, the rock hardness data is collected once every 0.5 seconds, the feed depth data is collected once every 0.3 seconds, and the sampling scraper pressure data is collected once every 0.5 seconds.

[0009] Furthermore, the criterion for determining the abrupt change in rock strata characteristics is: the difference between the rock strata hardness data collected in a single collection and the data collected in the previous collection is >10MPa / s; The MCU unit has a parameter adjustment response time of ≤0.2s for sudden changes in rock strata characteristics, and the adjusted parameters directly match the corresponding adaptive parameter threshold of the rock strata after the sudden change, avoiding overload damage to the servo adjustable speed motor or excessive compression and breakage of the sample by the sampling scraper.

[0010] Furthermore, the vertical reciprocating stroke of the sampling scraper is 5cm±1cm, and the reciprocating frequency is adapted to the rotational speed of the servo adjustable speed motor. The low-speed rotation speed of the sampling rod is 1 / 3 of the speed adapted by the current servo adjustable speed motor, and the rotation direction is consistent with the drilling rotation direction of the drill bit. After the sampling scraper extends, the pressure sensor provides real-time feedback on the pressure data. If the pressure deviates from the appropriate thrust of the current rock layer by ±5N, the MCU unit adjusts the output thrust of the micro electric push rod to bring the sampling scraper pressure back to the appropriate range.

[0011] Furthermore, the sample quality is determined by the sample perturbation rate, which is calculated as follows: ; The acceptable threshold for sample disturbance rate is as follows: soft rock ≤10%, medium-hard rock ≤5%, hard rock ≤3%. If the sample disturbance rate exceeds the acceptable threshold, the MCU unit will automatically correct the next sampling parameters: reduce the thrust of the micro electric actuator by 5-10N in the soft rock scenario, fine-tune the speed of the servo adjustable motor by ±50rpm in the medium-hard rock scenario, and reduce the downward movement speed of the variable frequency feed motor by 0.5-1mm / s in the hard rock scenario.

[0012] Furthermore, the indentation hardness sensor is fixed to the cutting teeth at the front end of the drill bit by welding, and the sensor detection surface is flush with the cutting surface of the drill bit to ensure real-time contact with the rock layer and accurate collection of hardness data. The displacement sensor is fixed to the outer wall of the sampling rod by bolts, and the installation position is located 5-8cm above the barrier ring. The sensor detection direction is parallel to the axis of the sampling rod. The pressure sensor is embedded in the piston rod end of the telescopic rod, and the sensor detection surface is in complete contact with the force-bearing end of the telescopic rod to ensure accurate pressure data acquisition.

[0013] Furthermore, the deceleration process of the variable frequency feed motor is linear, with a deceleration time of 0.5-1s, to avoid sudden deceleration causing vibration of the drill rod and sampling rod; When the displacement sensor detects that the feed depth has reached the target sampling depth, the variable frequency feed motor immediately stops running and the drill rod position is locked by the electromagnetic braking mechanism to prevent the sampling rod from continuing to move downward due to gravity, which would cause a deviation in the sampling depth. The sampling time of the sampling scraper is preset to 30s±5s. If the pressure sensor detects that there is no significant increase in the pressure of the sampling scraper within 5 consecutive seconds, the MCU unit determines that the sampling is complete and triggers the reset action in advance.

[0014] Furthermore, the host computer is connected to the MCU unit via USB wired connection or Bluetooth wireless connection, and the host computer is equipped with a parameter input visualization interface. During on-site investigation, if preliminary geological data of the investigation area is known, the preset parameter templates of the corresponding rock strata can be directly called through the host computer without re-entering them, thus improving operational efficiency.

[0015] Furthermore, the sampling data recorded by the MCU unit includes: sampling time, survey location coordinates, rock layer hardness variation curve, parameter adjustment records of each actuator, and sample disturbance rate; The MCU unit has a self-learning optimization function. After 10 samplings of the same type of rock layer, it automatically calculates the average value of the adaptation parameters of the rock layer and updates the average value to a new preset threshold.

[0016] Compared with existing technologies, the above-mentioned drilling and sampling method for geotechnical engineering exploration adapted to different rock strata provided by this invention collects rock hardness, feed depth, and sampling scraper pressure data in real time through indentation hardness sensors, displacement sensors, and pressure sensors. An MCU unit compares preset thresholds to determine the type of soft, medium-hard, or hard rock, and dynamically adjusts the servo adjustable speed motor speed, micro-electric push rod thrust, and variable frequency feed motor feed speed, enabling a response to sudden changes in rock strata within 0.2 seconds. Simultaneously, sampling accuracy is ensured through scraper coordinated action, pressure closed-loop control, linear deceleration, and braking lock. Sampling data is automatically recorded, and parameters are optimized after multiple samplings of the same type of rock strata. This method has strong rock strata adaptability, stable sample quality, high automation, and self-optimization capabilities. It can be modified based on existing equipment, facilitating widespread application. Attached Figure Description

[0017] Figure 1 A flowchart of a geotechnical engineering exploration drilling and sampling method provided in an embodiment of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0019] It should be noted that, unless otherwise specifically stated, the relative arrangement and numerical expressions of the components and steps described in these embodiments should not be construed as limiting the scope of the invention.

[0020] The following description of exemplary embodiments is merely illustrative and is not intended to limit the invention or its application or use in any way. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail herein, but where applicable, such techniques, methods, and apparatus should be considered part of this specification.

[0021] Example 1 See Figure 1 , Figure 1 This is a flowchart illustrating a drilling and sampling method for geotechnical engineering exploration adapted to different rock strata, as proposed in this invention. It addresses the problems of existing drilling and sampling technologies, such as fixed parameters being unable to adapt to different rock strata, unstable sample quality, low automation, and lack of self-optimization capabilities. The method is based on a geotechnical engineering exploration drilling and sampling device, whose structure includes basic mechanical components and functional components, specifically including: Basic mechanical structure: The drill rod serves as the main support, with the sampling rod nested inside and having a sampling port on its surface; the drill bit is mounted on the end of the sampling rod for cutting rock strata, and an isolation ring is fitted over the outer wall of the sampling rod and corresponds to the sampling port to control its opening and closing; the sampling scraper is connected to the inner wall of the sampling rod via a telescopic rod and can extend / retract the sampling port; the motor box has a built-in drive component to provide power for the overall drilling and sampling operations.

[0022] Functional components and installation: The indentation hardness sensor is fixed next to the drill bit cutting teeth, with the detection surface flush with the drill bit cutting surface to ensure real-time contact with the rock layer; the displacement sensor is installed on the outer wall of the sampling rod, 5-8cm above the barrier ring, with the detection direction parallel to the axis of the sampling rod to accurately collect depth; the pressure sensor is embedded in the end of the telescopic rod, with the detection surface in contact with the force-bearing end of the telescopic rod to avoid pressure data deviation; the servo adjustable speed motor, the micro electric push rod, and the variable frequency feed motor are respectively connected to the drill rod to control the rotation speed, scraper thrust, and feed speed; the MCU unit is fixed in the motor box and connects each sensor to the drive component through wires, which pass through pre-set holes in the inner wall of the sampling rod to avoid interfering with mechanical action.

[0023] The specific steps of the geotechnical engineering exploration drilling and sampling method adapted to different rock strata of the present invention may include: S1. Parameter preset: Input the adaptation parameter thresholds for different rock layers to the MCU unit through the host computer, and preset the target sampling depth and feed speed trigger conditions at the same time. S11. Connect the host computer (industrial panel PC, model: IPC-610L) to the MCU unit via USB wired connection (or Bluetooth 5.0 wireless connection). The host computer has a visual parameter input interface (including a rock layer type selection box, parameter value input box, and threshold save / recall button). If the preliminary geological data of the exploration area is known (e.g., the previous drilling log shows that the area is mainly soft rock and medium-hard rock), simply click the "Parameter Template Recall" button on the interface to retrieve the pre-saved soft rock and medium-hard rock parameter templates without having to re-enter them.

[0024] S12. If no template can be called, the host computer inputs the threshold values ​​of different rock strata adaptation parameters to the MCU unit: Soft rock (rock hardness ≤15MPa): servo adjustable speed motor speed 1800rpm±50rpm, micro electric push rod thrust 30N±5N, variable frequency feed motor drives the drill rod downward speed 8mm / s±0.5mm / s; Medium-hard rock (15MPa < rock hardness ≤ 30MPa): servo adjustable speed motor speed 1500rpm±50rpm, micro electric push rod thrust 50N±5N, variable frequency feed motor drive drill rod downward movement speed 5mm / s±0.5mm / s; Hard rock (rock hardness > 30MPa): servo adjustable speed motor speed 1200rpm±50rpm, micro electric push rod thrust 80N±5N, variable frequency feed motor drives drill rod downward movement speed 3mm / s±0.5mm / s; Meanwhile, a preset target sampling depth of 20cm ± 0.5cm is used to trigger the feed speed: when the feed depth is 1cm away from the target sampling depth, the speed of the variable frequency feed motor is reduced to 50% of the current speed. The parameters are transmitted to the MCU unit through the host computer and then stored in the MCU's internal flash memory (capacity 1MB).

[0025] S2. Drilling and Real-time Monitoring: Start the variable frequency feed motor to drive the drill rod, sampling rod and drill bit to move down and rotate synchronously for drilling. Each sensor collects rock hardness data, feed depth data and sampling scraper pressure data in real time and transmits them to the MCU unit. S21, Drilling Start: The MCU unit outputs a control signal to start the variable frequency feed motor and the servo adjustable speed motor, driving the drill rod, sampling rod and drill bit to move down and rotate synchronously for drilling (the initial rotation speed / feed speed is set according to the regional dominant rock layer parameters preset in S1. For example, if the exploration area is mainly soft rock, the initial rotation speed is 1800 rpm and the feed speed is 8 mm / s).

[0026] S22. Real-time data acquisition: Each sensor operates strictly according to the acquisition frequency, specifically including: Indentation hardness sensor: Collects rock hardness data once every 0.5s. Because the sensor detection surface is flush with the drill bit cutting surface, it can directly contact the rock layer, and the data error is ≤±0.5MPa. Displacement sensor: Collects feed depth data once every 0.3s. Because the installation direction is parallel to the axis of the sampling rod, the depth data accuracy reaches ±0.1cm. Pressure sensor: Sample scraper pressure data is collected every 0.5s (in the initial stage, the scraper is not extended and the pressure value is 0N). Because the detection surface is completely in contact with the force-bearing end of the telescopic rod, there is no lag in the pressure data. All collected data is transmitted to the MCU unit via wires, and after A / D conversion, it is temporarily stored in RAM (capacity 512KB) and simultaneously uploaded to the host computer for real-time display.

[0027] S3. Rock Layer Determination and Dynamic Parameter Adjustment: The MCU unit compares the received rock layer hardness data with the rock layer threshold preset in step S1 to determine the type of rock layer being drilled, and then outputs control signals to adjust the speed of the servo adjustable speed motor, the thrust of the micro electric push rod, and the feed speed of the variable frequency feed motor; if a sudden change in rock layer characteristics is detected, the MCU unit will urgently adjust the parameters of each actuator. S31. Rock type determination: The MCU unit compares the real-time received rock hardness data with the preset threshold in step S1, and outputs the rock type determination result (soft rock / medium-hard rock / hard rock) every 1 second: if the hardness is ≤15MPa, it is determined to be soft rock; if 15MPa < hardness ≤30MPa, it is determined to be medium-hard rock; if the hardness is >30MPa, it is determined to be hard rock.

[0028] S32. Routine Parameter Adjustment: If the determined rock layer type does not match the current execution parameters, the MCU unit immediately outputs a control signal: Adjust the speed of the servo adjustable motor (e.g., switch from 1800rpm for soft rock to 1500rpm for medium-hard rock). Adjust the thrust of the miniature electric actuator (e.g., switch from 50N for medium-hard rock to 80N for hard rock). Adjust the feed speed of the variable frequency feed motor (e.g., switch from 3mm / s for hard rock to 8mm / s for soft rock).

[0029] S33. Rock Stratum Abruptness Handling: If the difference between the rock stratum hardness data acquired in a single acquisition and the data acquired in the previous acquisition is detected to be >10MPa / s, the MCU unit will complete the emergency parameter adjustment within ≤0.2s. For example, if the original drilling stratum is soft rock (hardness 8MPa), and the hardness suddenly jumps to 32MPa (hard rock), the MCU unit will immediately switch the parameters to the hard rock adaptation values ​​(rotation speed 1200rpm, thrust 80N, feed speed 3mm / s) to ensure that the adjusted parameters directly match the rock stratum after the abrupt change, thus avoiding servo motor overload or scraper blade compression of the sample.

[0030] S4. Precise Sampling: The displacement sensor provides real-time feedback of the feed depth data. When the depth reaches the feed speed trigger condition, the MCU unit controls the variable frequency feed motor to slow down. When the depth reaches the target sampling depth, the variable frequency feed motor stops driving. Subsequently, the MCU unit controls the blocking ring to release the obstruction of the sampling port on the sampling rod surface, drives the sampling scraper to extend from the sampling port, and controls the sampling scraper to move back and forth in the vertical direction, while controlling the sampling rod to rotate at a low speed. S41. Feed speed control: The displacement sensor provides real-time feedback on the feed depth. When the depth is only 1cm away from the target sampling depth (20cm), the MCU unit controls the variable frequency feed motor to reduce the speed in a linear deceleration manner until the speed drops to 50% of the current speed (e.g., from 8mm / s to 4mm / s for soft rock).

[0031] S42. Stop Lock: When the displacement sensor detects that the feed depth reaches 20cm±0.5cm, the MCU unit immediately controls the variable frequency feed motor to stop running and triggers the electromagnetic braking mechanism (braking torque 6N・m) to lock the drill rod position, preventing the sampling rod from continuing to move downward due to gravity and causing depth deviation.

[0032] S43. Sampling Action Execution: After completing the feed stop and drill rod locking, the MCU unit executes the sampling action sequentially: First, it controls the blocking ring drive motor to rotate forward, causing the blocking ring to move 15mm downward along the sampling rod axis, thus removing the obstruction to the sampling port; then, it controls the micro electric push rod to push the telescopic rod to extend, so that the sampling scraper extends 20mm from the sampling port to contact the rock layer; subsequently, it controls the sampling scraper to move back and forth in the vertical direction with a stroke of 5cm±1cm, and the reciprocating frequency is adapted to the speed of the servo adjustable speed motor (e.g., when the servo speed is 1800rpm, the reciprocating frequency is 1800 / 60=30 times / second), while controlling the sampling rod to rotate at a low speed of 1 / 3 of the current servo adjustable speed motor speed (e.g., when the servo speed is 1500rpm, the sampling rod speed is 500rpm), and the rotation direction is consistent with the drilling direction of the drill bit. During this process, pressure closed-loop control is performed simultaneously. The pressure sensor provides real-time feedback on the scraper pressure. If the pressure deviates from the current rock layer's suitable thrust by ±5N (e.g., for soft rock, the thrust deviates by 30N ±5N), the MCU unit fine-tunes the output of the miniature electric actuator through a PWM signal, adjusting by ±1N each time, until the pressure returns to the suitable range. Finally, according to the preset sampling time of 30s ±5s (e.g., 32s for soft rock sampling), if the pressure sensor detects a scraper pressure change of ≤2N (no significant increase) within 5 consecutive seconds, the MCU unit directly determines that sampling is complete and triggers a reset action in advance.

[0033] S5. Sampling Reset and Parameter Optimization: After sampling is completed, the MCU unit controls the sampling scraper to retract into the sampling rod, the blocking ring to reset and block the sampling port, and then controls the variable frequency feed motor to run in reverse to drive the drill rod and sampling rod to move to the ground; after the sample is taken out, the MCU unit records the sampling data and automatically corrects the adaptation parameter threshold for the next sampling based on the sample quality.

[0034] S51. After sampling is completed, the MCU unit controls the components to reset in the following order: the miniature electric push rod retracts, driving the sampling scraper to return to the inside of the sampling rod; the blocking ring drive motor reverses, driving the blocking ring to move upward and reset, and blocking the sampling port again; the frequency conversion feed motor runs in reverse, driving the drill rod and sampling rod to move upward to the ground at a speed of 10mm / s.

[0035] S52. Sample Quality Judgment and Parameter Correction: Remove the sample from the sampling scraper, measure the actual density of the sample using a densitometer, and calculate the sample perturbation rate according to the formula. (The natural density of the rock strata was obtained from previous exploration data, such as the natural density of soft rock being 1.8 g / cm³). Acceptance Criteria and Parameter Correction: If the disturbance rate exceeds the acceptable threshold (soft rock > 10%, medium-hard rock > 5%, hard rock > 3%), the MCU unit will automatically correct the next sampling parameters. Soft rock scenario: Reduce the thrust of the miniature electric actuator by 5-10N (e.g., from 30N to 25N); Medium-hard rock scenario: fine-tune the servo adjustable speed motor speed ±50rpm (e.g., from 1500rpm to 1550rpm). For hard rock scenarios: reduce the downward movement speed of the variable frequency feed motor by 0.5-1 mm / s (e.g., from 3 mm / s to 2.5 mm / s).

[0036] S53. Data Recording and Self-Learning Optimization: Automatically record sampling data, including: sampling time (accurate to the second, such as 2024-10-01 14:30:25), survey location coordinates (obtained through the host computer's GPS module, such as 30°15′N, 120°30′E), rock layer hardness change curve (one data point every 0.5s, forming a complete curve), parameter adjustment records of each actuator (such as the time point when the rotation speed switches from 1800rpm to 1500rpm), and sample disturbance rate (such as 8% disturbance rate for soft rock). After every 10 samplings of the same type of rock strata (e.g., 10 soft rock samplings), the MCU unit automatically calculates the average value of the adaptive parameters for that rock strata (e.g., the average thrust of 10 soft rock samplings is 28N), and updates the average value to a new preset threshold, overwriting the original threshold, thus achieving parameter self-optimization.

[0037] In summary, the present invention has the following advantages: 1. Through real-time hardness detection and dynamic parameter adaptation mechanism, data is collected by hardness sensor, rock type is determined by MCU unit and corresponding parameters are automatically matched. In the face of sudden changes in rock layer, parameters can be quickly switched to achieve adaptation to all types of strata from soft rock to hard rock, avoiding overload of the mechanism or damage to the sample. 2. By using the coordinated action of the scraper and the closed-loop control of pressure to stabilize the sampling force, combined with the linear deceleration and braking lock control of the feeding stage to control the depth, and combined with the standardized sample quality quantitative judgment method, the soft rock disturbance rate is reduced, the hard rock integrity rate is improved, and the depth deviation and human subjective error are reduced. 3. By calling the parameter template of the host computer, the MCU unit automatically completes the rock layer determination, parameter adjustment, sampling execution and reset. Real-time data feedback from the sensor replaces manual observation, reduces manual intervention, shortens sampling time, reduces reliance on the professional experience of operators, and ensures stable sampling quality. 4. The MCU unit automatically records key sampling data to form a traceable database. Combined with the average parameter calculation and update after multiple samplings of the same type of rock strata, the subsequent sampling parameters are more in line with the actual rock strata characteristics of the area, and the sampling accuracy is continuously improved through iterative improvement. 5. By adapting the component design to existing conventional drilling and sampling devices, there is no need to redesign the overall framework. The modification process does not damage the core structure of the original device, reducing the equipment cost and modification difficulty of technology implementation, and facilitating rapid promotion in existing exploration scenarios.

[0038] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata, based on a drilling and sampling device for geotechnical engineering exploration, wherein the drilling and sampling device includes a drill rod, a sampling rod, a drill bit, a baffle ring, a sampling scraper, a motor housing, and a telescopic rod, and wherein the device is equipped with an indentation hardness sensor, a displacement sensor, a pressure sensor, a servo variable speed motor with adjustable rotation speed, a miniature electric push rod with adjustable thrust, a variable frequency feed motor with adjustable feed speed, and an MCU unit for data processing, characterized in that the steps are... include: S1. Input the adaptation parameter thresholds for different rock layers to the MCU unit through the host computer, and at the same time preset the target sampling depth and feed speed trigger conditions. S2. Start the variable frequency feed motor to drive the drill rod, sampling rod and drill bit to move down and rotate synchronously for drilling. Each sensor collects rock hardness data, feed depth data and sampling scraper pressure data in real time and transmits them to the MCU unit. S3. The MCU unit compares the received rock hardness data with the rock threshold preset in step S1 to determine the type of rock currently being drilled, and then outputs control signals to adjust the speed of the servo adjustable motor, the thrust of the micro electric push rod, and the feed speed of the variable frequency feed motor; if a sudden change in rock characteristics is detected, the MCU unit urgently adjusts the parameters of each actuator. S4. The displacement sensor provides real-time feedback of the feed depth data. When the depth reaches the feed speed trigger condition, the MCU unit controls the variable frequency feed motor to slow down. When the depth reaches the target sampling depth, the variable frequency feed motor stops driving. Subsequently, the MCU unit controls the blocking ring to release the obstruction of the sampling port on the sampling rod surface, drives the sampling scraper to extend from the sampling port, and controls the sampling scraper to reciprocate in the vertical direction, while controlling the sampling rod to rotate at a low speed. S5. After sampling is completed, the MCU unit controls the sampling scraper to retract into the sampling rod, the blocking ring to reset and block the sampling port, and then controls the variable frequency feed motor to run in reverse to drive the drill rod and sampling rod to move to the ground. After the sample is taken out, the MCU unit records the sampling data and automatically corrects the adaptation parameter threshold for the next sampling based on the sample quality.

2. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The specific threshold values ​​for the adaptation parameters of different rock strata are as follows: Soft rock adaptation parameters: servo adjustable speed motor speed 1800rpm±50rpm, micro electric push rod thrust 30N±5N, variable frequency feed motor drive drill rod downward movement speed 8mm / s±0.5mm / s; Medium-hard rock adaptation parameters: servo adjustable speed motor speed 1500rpm±50rpm, micro electric push rod thrust 50N±5N, variable frequency feed motor drive drill rod downward movement speed 5mm / s±0.5mm / s; Hard rock adaptation parameters: servo adjustable speed motor speed 1200rpm±50rpm, micro electric push rod thrust 80N±5N, variable frequency feed motor drive drill rod downward movement speed 3mm / s±0.5mm / s.

3. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The rock hardness data is collected once every 0.5 seconds, the feed depth data is collected once every 0.3 seconds, and the sampling scraper pressure data is collected once every 0.5 seconds.

4. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The criterion for determining the sudden change in rock strata characteristics is: the difference between the rock strata hardness data collected in a single collection and the data collected in the previous collection is >10MPa / s; The MCU unit has a parameter adjustment response time of ≤0.2s for sudden changes in rock strata characteristics, and the adjusted parameters directly match the corresponding adaptive parameter threshold of the rock strata after the sudden change, avoiding overload damage to the servo adjustable speed motor or excessive compression and breakage of the sample by the sampling scraper.

5. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The vertical reciprocating travel of the sampling scraper is 5cm±1cm, and the reciprocating frequency is adapted to the speed of the servo adjustable speed motor. The low-speed rotation speed of the sampling rod is 1 / 3 of the speed adapted by the current servo adjustable speed motor, and the rotation direction is consistent with the drilling rotation direction of the drill bit. After the sampling scraper extends, the pressure sensor provides real-time feedback on the pressure data. If the pressure deviates from the appropriate thrust of the current rock layer by ±5N, the MCU unit adjusts the output thrust of the micro electric push rod to bring the sampling scraper pressure back to the appropriate range.

6. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The sample quality is determined by the sample perturbation rate, which is calculated as follows: ； The acceptable threshold for sample disturbance rate is as follows: soft rock ≤10%, medium-hard rock ≤5%, hard rock ≤3%. If the sample disturbance rate exceeds the acceptable threshold, the MCU unit will automatically correct the next sampling parameters: reduce the thrust of the micro electric actuator by 5-10N in the soft rock scenario, fine-tune the speed of the servo adjustable motor by ±50rpm in the medium-hard rock scenario, and reduce the downward movement speed of the variable frequency feed motor by 0.5-1mm / s in the hard rock scenario.

7. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The indentation hardness sensor is fixed to the cutting teeth at the front end of the drill bit by welding, and the sensor detection surface is flush with the cutting surface of the drill bit to ensure real-time contact with the rock layer and accurate collection of hardness data. The displacement sensor is fixed to the outer wall of the sampling rod by bolts, and the installation position is located 5-8cm above the barrier ring. The sensor detection direction is parallel to the axis of the sampling rod. The pressure sensor is embedded in the piston rod end of the telescopic rod, and the sensor detection surface is in complete contact with the force-bearing end of the telescopic rod to ensure accurate pressure data acquisition.

8. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The deceleration process of the variable frequency feed motor is linear, with a deceleration time of 0.5-1s, to avoid sudden deceleration that could cause vibration of the drill rod and sampling rod. When the displacement sensor detects that the feed depth has reached the target sampling depth, the variable frequency feed motor immediately stops running and the drill rod position is locked by the electromagnetic braking mechanism to prevent the sampling rod from continuing to move downward due to gravity, which would cause a deviation in the sampling depth. The sampling time of the sampling scraper is preset to 30s±5s. If the pressure sensor detects that there is no significant increase in the pressure of the sampling scraper within 5 consecutive seconds, the MCU unit determines that the sampling is complete and triggers the reset action in advance.

9. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The host computer is connected to the MCU unit via USB wired connection or Bluetooth wireless connection, and the host computer is equipped with a parameter input visualization interface. During on-site investigation, if preliminary geological data of the investigation area is known, the preset parameter templates of the corresponding rock strata can be directly called through the host computer without re-entering them, thus improving operational efficiency.

10. The method for drilling and sampling in geotechnical engineering exploration adapted to different rock strata as described in claim 1, characterized in that, The sampling data recorded by the MCU unit includes: sampling time, survey location coordinates, rock layer hardness variation curve, parameter adjustment records of each actuator, and sample disturbance rate; The MCU unit has a self-learning optimization function. After 10 samplings of the same type of rock layer, it automatically calculates the average value of the adaptation parameters of the rock layer and updates the average value to a new preset threshold.

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