Soil sampling method and device for mineral geology and geotechnical investigation

Abstract

The invention relates to the technical field of soil sampling, in particular to a soil sampling method and device for mineral geology geotechnical investigation. Through the infrared distance sensor and the air pressure sensor which are arranged at the top of the sampling pipe, filling height data and internal air pressure data of soil in the pipe can be synchronously collected at high frequency in the process of pressing the sampling pipe into the stratum, and a relation curve of the two groups of data is dynamically constructed and analyzed by the system; the interface of different stratums such as a sandy soil layer and a clay layer can be intelligently identified in situ by calculating the significant change of the curvature of the curve in real time, and the traditional blind sampling mode depending on the hand feeling of an operator and post sample analysis is converted into a data-driven and transparent perceptual sampling mode by the technology. The objectivity, accuracy and timeliness of stratum identification are greatly improved, and a key basis is provided for on-site instant optimization of an exploration scheme.

Description

Technical Field

[0001] This invention relates to the field of soil sampling technology, and in particular to a soil sampling method and apparatus for mineral geological and soil exploration. Background Technology

[0002] In fields such as mineral geological exploration, geotechnical engineering investigation, and environmental geological survey, soil sampling is a fundamental and crucial technical means for obtaining underground geological information, assessing the engineering properties of soil layers, and conducting geochemical analysis. Its core objective is to obtain soil samples that accurately represent the in-situ stratigraphic structure and physical and mechanical properties with minimal disturbance.

[0003] Traditional soil sampling methods primarily rely on various mechanical samplers (such as thin-walled samplers, standard penetrators, and augers) in conjunction with drilling rigs. The sampling process typically involves: establishing sampling points according to the exploration plan; using the drilling rig to drive, penetrate, or rotate the sampler into the target stratum; and then lifting it to the surface to obtain samples. However, these traditional methods have several inherent drawbacks:

[0004] The sampling process relies on experience and is somewhat arbitrary. During the drilling process, operators mainly rely on subjective experience such as the resistance and sound feedback from the drilling rig to roughly judge the changes in the formation. For formations with similar lithology but significantly different engineering properties, it is difficult to achieve accurate and objective interface identification. The accurate identification of formation properties is severely delayed, and it is usually necessary to visually identify the samples after they are taken out or send them to the laboratory for analysis before a final determination can be made. This cannot provide an immediate basis for real-time adjustments to the process during drilling.

[0005] Sampling quality is difficult to guarantee, as samples are easily disturbed or detached, especially when dealing with non-cohesive sandy soils, silt, or gravelly strata. Existing soil samplers mainly rely on the friction between the soil and the pipe wall or simple mechanical valves to hold the sample during the lifting process. This method has low reliability, and the sample is extremely prone to relative sliding, partial detachment, or even complete loss within the pipe due to vibration, its own weight, or erosion by groundwater. This leads to sampling failure or the obtained sample lacking representativeness and failing to meet the requirements for high-quality undisturbed samples.

[0006] With fixed process parameters and a lack of adaptive optimization capabilities, traditional sampling operations typically employ preset, fixed compression speeds or impact energies. The inability to dynamically adjust the compression force or speed based on real-time formation responses (such as changes in softness, hardness, and density) can lead to squeezing disturbances in soft soil layers due to excessive compression, or ineffective penetration in hard soil layers due to insufficient energy, thus affecting sampling efficiency and sample quality.

[0007] To address these issues, some improvements have emerged in existing technologies, such as integrating torque and pressure sensors onto the drill pipe to monitor drilling parameters, or designing more complex internal structures for the soil sampler to hold the sample. However, these solutions either only provide indirect and comprehensive operating parameters, making it difficult to directly and sensitively deduce specific lithological information of the formation; or they tend to be structurally complex, reducing reliability, and still fail to fundamentally achieve real-time, in-situ, intelligent diagnosis of the sampling process and closed-loop control of sample preservation.

[0008] Therefore, developing a soil sampling device and method that can identify formation characteristics and interfaces in real time and accurately during the sampling process, and can intelligently adjust the process accordingly, while ensuring that samples (especially loose samples) are safely and completely extracted, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0009] To achieve the above objectives, this invention proposes a soil sampling method and apparatus for mineral geological and soil exploration, comprising the following steps:

[0010] Step 1: Equipment preparation and parameter setting. Install the sampling tube to the execution end of the stamping mechanism. Install an infrared distance sensor and a pressure sensor at the top of the sampling tube. Initialize the system, calibrate the sensors, and set the target sampling depth, initial pressing speed, and curvature change threshold.

[0011] Step 2: Pressing down for sampling and simultaneous data acquisition. The pressing mechanism is controlled to press the sampling tube into the formation at a constant speed, while simultaneously acquiring data measured by an infrared distance sensor. And calculate the distance the soil penetrates into the sampling tube. And the air pressure inside the sampling tube measured by the air pressure sensor. ;

[0012] Step 3: Real-time analysis and identification of stratigraphic characteristics and interfaces, based on the distance of the soil sampled into the tube in real time. air pressure inside the sampling tube Data, constructing and updating the distance of soil penetration into the sampling tube. air pressure inside the sampling tube The relationship curve is calculated, and the real-time curvature K of the curve is used to determine the formation homogeneity or identify the formation interface based on the change of curvature K. When the curvature K changes significantly, it is determined that the formation interface has been crossed and the interface depth is recorded.

[0013] Step 4: Sampling process adaptive adjustment based on real-time information. After acquiring real-time formation information, the system optimizes the sampling process in real time, including the following adjustment methods:

[0014] If the layer is determined to be a single homogeneous layer, continue sampling at the current pressing speed;

[0015] If it is detected that the formation has entered a viscous formation, the pressing speed of the pressing mechanism will be reduced automatically or manually to reduce the disturbance to the formation.

[0016] If a formation interface is identified and its depth is recorded, the system will issue an alert and can output a formation interface report after sampling is completed.

[0017] In one example, after sampling at the target depth, the fifth step, negative pressure adsorption and sample lifting, is performed. This includes establishing negative pressure and closed-loop control lifting steps. To establish negative pressure, the solenoid valve is opened, and the vacuum pump is started to extract gas from the tube. The soil at the bottom of the sampling tube is used to seal and form a negative pressure chamber until the air pressure... The preset target negative pressure value has been reached, and closed-loop control is in progress, continuously monitoring the air pressure. The controller dynamically adjusts the lifting speed to maintain stable negative pressure; if a decrease in negative pressure is detected, the lifting speed is reduced.

[0018] In one example, in the third step, if the curvature K value remains stable during continuous downward pressure or its fluctuation is below a set threshold, the current depth segment is determined to be a single homogeneous stratum. If the curvature K value increases sharply over a short distance, it is determined to be a transition from a highly permeable stratum to a less permeable viscous stratum.

[0019] In one example, after the third step identifies the entry into a viscous formation, the fourth step adjusts the sampling process based on real-time information, automatically or manually reducing the pressing speed of the stamping mechanism.

[0020] In one example, the distance the soil penetrates into the sampling tube in the second step... Calculate using the following formula:

[0021] ,

[0022] in, This refers to the fixed distance between the infrared distance sensor detection end of the sampling tube and the bottom of the sampling tube. This refers to the real-time distance detected by the infrared distance sensor.

[0023] In one example, in the second step, if the system determines that the entire stratum is a sand and gravel layer based on the continuously low curvature K within the target sampling depth, then the system controls the pressing mechanism to continue pressing down the sampling tube until the curvature K increases sharply in accordance with the characteristics of cohesive strata, so that a cohesive soil plug is formed at the bottom of the sampling tube.

[0024] In one example, a soil sampling device for mineral geological and soil exploration includes a pressing mechanism and a sampling tube. The pressing mechanism provides downward and upward power to the sampling tube, and the sampling tube is connected to the execution end of the pressing mechanism for downward sampling. The bottom end of the sampling tube is tapered, and an infrared distance sensor and a pressure sensor are installed at the top end of the sampling tube. The sampling device also includes a controller, which is signal-connected to the pressing mechanism, the infrared distance sensor, and the pressure sensor.

[0025] The infrared distance sensor is used to detect the soil surface height inside the pipe in real time. and deliver it to the controller;

[0026] The pressure sensor is used to detect the internal pressure of the sampling tube in real time. The contents are delivered to the controller.

[0027] The controller receives real-time data on the distance the soil penetrates into the sampling tube. air pressure inside the sampling tube Construct and update the distance of soil penetration into the sampling tube. air pressure inside the sampling tube The relationship curve is calculated, and the real-time curvature K of the curve is used to determine the homogeneity of the formation or identify the formation interface based on the change of curvature K. When the curvature K undergoes a significant abrupt change, it is determined that the formation interface has been crossed and the interface depth is recorded. Based on the judgment result, the pressing speed of the stamping mechanism is controlled or a warning message is triggered.

[0028] In one example, a soil sampling device for mineral geological and soil exploration also includes a solenoid valve fixedly installed at the top of the sampling tube, a vacuum machine fixedly installed on the upper surface of the stamping mechanism, the vacuum machine being connected to the solenoid valve through a pipe, the suction end of the solenoid valve extending to the inner top of the sampling tube, and both the solenoid valve and the vacuum machine being signal-connected to the controller.

[0029] The soil sampling method and apparatus for mineral geological and soil exploration proposed in this invention can bring the following beneficial effects:

[0030] 1. This invention, through the infrared distance sensor and air pressure sensor installed at the top of the sampling tube, can simultaneously and frequently collect data on the filling height of the soil and the internal air pressure of the tube during the process of pressing the sampling tube into the formation. The system dynamically constructs and analyzes the relationship curve between these two sets of data. By calculating significant changes in the curvature of the curve in real time, it can intelligently and in situ identify the interface between different strata such as sand and clay layers. This technology transforms the traditional blind sampling mode that relies on the operator's feel and post-sample analysis into a data-driven, transparent, and perceptual sampling method, which greatly improves the objectivity, accuracy, and timeliness of stratum identification and provides key basis for optimizing exploration plans on-site.

[0031] 2. This invention utilizes a negative pressure adsorption and closed-loop control lifting mechanism, combined with real-time formation information for adaptive process adjustment. The system uses the identified bottom dense clay layer as a natural seal, actively pumping air to establish and maintain a stable negative pressure at the top of the sampling tube, thereby generating a uniform and strong adsorption force on the soil sample column. During the lifting process, the controller dynamically adjusts the lifting speed based on real-time feedback from the pressure sensor, forming a closed-loop control to ensure stable sample stress. For special conditions such as all-sand layers, the system can also make intelligent decisions to continue pressing down to find the underlying clay layer to form an effective seal. This integrated active preservation strategy significantly improves the sampling rate, integrity, and reliability of undisturbed samples in complex formations. Attached Figure Description

[0032] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0033] Figure 1 This is a schematic diagram of a three-dimensional structure of a soil sampling device for mineral geological and soil exploration.

[0034] Figure 2 This is a soil sampling device for mineral geological and soil exploration. Figure 1 Enlarged structural diagram at point A in the middle;

[0035] Figure 3 This is a schematic diagram of the process structure of a soil sampling method for mineral geological and soil exploration.

[0036] The attached figures are labeled as follows:

[0037] 1. Stamping mechanism, 2. Sampling tube, 3. Infrared distance sensor, 4. Pressure sensor, 5. Controller, 6. Solenoid valve, 7. Vacuum machine. Detailed Implementation

[0038] To more clearly illustrate the overall concept of the present invention, a detailed description will be provided below with reference to the accompanying drawings and examples.

[0039] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] like Figures 1 to 3 As shown, this invention proposes a soil sampling method and apparatus for mineral geological and soil exploration. The sampling method includes the following steps:

[0043] Example 1

[0044] Step 1: Equipment Initialization and Parameter Setting. After selecting the drilling location and securely installing the equipment, system preparation is performed. A clean sampling tube 2 is installed at the execution end of the pressing mechanism 1, and an infrared distance sensor 3 and a pressure sensor 4 are installed at the top of the sampling tube 2. At the same time, a controller 5 for controlling the pressing mechanism 1 is installed on the pressing mechanism 1. The controller 5 receives data from the infrared distance sensor 3 and the pressure sensor 4. After the system is powered on, the controller 5 automatically performs sensor self-checks and calibrations. Key calibrations include recording the reference distance from the infrared distance sensor 3 to the bottom of the sampling tube 2 under no-load conditions and calibrating the reading of the pressure sensor 4. Subsequently, the operator sets the key parameters for this operation through the human-machine interface, including the target sampling depth, initial pressing speed, and the curvature change threshold used to determine formation changes.

[0045] Step 2: Pressing and Sampling with Synchronous Data Acquisition. The automatic pressing program is initiated, and the pressing mechanism 1 smoothly presses the sampling tube 2 into the formation at a set constant speed. Simultaneously, the system synchronously acquires two core data streams at high frequency. One stream is the real-time distance from the top of the sampling tube 2 to the soil surface inside the tube, measured by the infrared distance sensor 3. This distance is then analyzed using a formula... ,in This refers to the distance the soil penetrates into the sampling tube 2, which is also the sample height. The fixed distance between the detection end of the infrared distance sensor 3 of the sampling tube 2 and the bottom of the sampling tube 2. The infrared distance sensor 3 detects the real-time distance, while the other path is the absolute air pressure inside the sealed cavity at the top of the sampling tube 2 measured by the barometric pressure sensor 4. .

[0046] Step 3: Real-time analysis and identification of formation characteristics and interfaces; controller 5 analyzes the collected data. and Data is processed and analyzed in real time.

[0047] Data preprocessing and curve construction: After filtering and denoising the original signal, the system dynamically constructs and updates curves based on soil filling height. The x-axis is the horizontal axis, and the absolute air pressure is the vertical axis. The curve represents the relationship along the y-axis.

[0048] Curvature calculation and feature extraction: To quantify the morphological changes of the curve, the system uses a numerical differentiation method to calculate the approximate curvature K of the curve at the current point in real time. Curvature K is a mathematical parameter that describes the degree of curvature of the curve. In this invention, it reflects the change in the rate of pressure change caused by a unit increment of soil, and comprehensively characterizes the permeability and compressibility of the soil.

[0049] When sampling tube 2 passes through a soil layer with uniform properties, such as a uniform sand layer or a uniform clay layer, the relationship curve shows a regular change. The calculated curvature K value remains stable within a sliding time window, and its fluctuation standard deviation is lower than the set value. The system then determines that the depth segment is a single stratum.

[0050] For stratigraphic interface identification, the system continuously monitors the rate of change of the curvature K value. When a significant abrupt change in the K value over a short distance is detected, it is determined that a stratigraphic interface has been crossed. Specifically, if the K value increases sharply, it indicates a sudden drop in soil permeability or a significant change in compressibility. A typical scenario is the transition from a loose sand and gravel layer to a dense clay layer. In this case, due to the sealing effect of the low-permeability clay, the gas inside the pipe is rapidly compressed, leading to… Follow The rate of increase accelerates, the curve becomes steeper, and the curvature increases.

[0051] If the K value decreases sharply and exceeds the negative threshold, it may indicate that the formation has entered from a dense layer into a highly porous or fractured formation, and the permeability has improved.

[0052] Once the system detects an interface, it immediately issues an audible and visual alarm, highlights the suspected interface depth on the operating interface, and automatically records the event. This judgment is far more sensitive and accurate than traditional methods relying on the feel of drilling rig operation or visual observation after sample removal.

[0053] Step 4: Sampling process adaptive adjustment based on real-time information. After obtaining real-time formation information, the system or operator can optimize the sampling process in real time. For example, when the system prompts that it has entered a soft clay layer, the pressing speed can be automatically or manually reduced from a higher penetration speed to a lower undisturbed sampling speed to minimize the squeezing and disturbance of sensitive formations, thereby obtaining higher quality undisturbed samples. At the same time, during the sampling process, if the system determines that the sampling tube 2 has entered the clay layer from the sand and gravel layer and has reached the sampling depth, the bottom clay layer can be used as a bottom seal to prevent the sand and gravel layer from falling. Alternatively, if the sampling depth is entirely composed of sand and gravel layers, drilling can continue into the clay layer for further sampling, which can avoid the sand and gravel falling due to raising the sampling tube 2 in the sand and gravel layer.

[0054] Example 2

[0055] Based on Example 1, a solenoid valve 6 is installed at the top of the sampling tube 2, and a vacuum machine 7 is installed on the stamping mechanism 1. The vacuum machine 7 is connected to the solenoid valve 6 through a pipe, and the vacuum machine 7 can be used to evacuate the air inside the sampling tube 2. The subsequent steps are as follows:

[0056] Step 5: Negative pressure adsorption and closed-loop controlled sample lifting. After completing the sampling at the target depth, we enter the critical stage of ensuring that the sample does not fall off.

[0057] To establish a stable negative pressure, controller 5 first opens solenoid valve 6, then starts vacuum pump 7 to extract gas from the top of sampling tube 2. Since there is clay at the bottom of sampling tube 2 as a barrier, the clay seals the bottom of sampling tube 2, reducing the air pressure inside sampling tube 2. Pressure sensor 4 provides real-time feedback. When the pressure reaches the preset target negative pressure value, the vacuum pump valve is closed, and the system enters a pressure-holding state. This negative pressure forms a strong and uniform adsorption force at the top of the soil sample, effectively offsetting the soil sample's own weight, especially creating a bottom-holding effect for loose soil samples at the bottom.

[0058] At this point, the sampling tube 2 is lifted. The lifting process is not uniform, but rather forms a closed-loop control system aimed at maintaining stable negative pressure. The controller 5 sets the initial lifting speed and continuously monitors the actual air pressure P. During the lifting process, any factor that causes the soil sample to slide, such as acceleration inertia, vibration, or changes in sidewall friction, will cause a slight change in the volume of the sealed cavity, thereby changing the pressure P. The controller 5 dynamically adjusts the lifting speed through a real-time algorithm. If a weakening of the negative pressure is detected, the lifting speed is immediately reduced to suppress the soil sample from sliding down. If the negative pressure remains unchanged or the change is small, the lifting is performed at a uniform speed. Through this real-time feedback and adjustment, the entire lifting process becomes extremely smooth, keeping the soil sample in a state of force balance until it is safely and completely removed from the orifice.

[0059] Based on the principles of Examples 1 and 2, this invention's method also possesses effective strategies to address the special condition where the exploration area may consist entirely of the target sand and gravel layers without any cohesive interlayers. When the system determines, based on the continuously low and gentle state of the LP curve curvature K value within the preset sampling depth, that all the traversed strata are homogeneous sand and gravel layers and the target depth has been reached, the controller 5 can execute the following optimization instructions:

[0060] The command continues to press down to find the sealing layer: the system can prompt the operator, or directly control the pressing mechanism 1 in automatic mode to continue pressing down the sampling tube 2 at a low speed until the curvature K value increases sharply in accordance with the characteristics of clay, indicating that the bottom of the sampling tube 2 has entered a cohesive soil layer that can act as a natural sealing plug, such as the residual clay at the bottom or the weathered clay layer of bedrock.

[0061] Perform ultra-deep sampling and seal formation. After confirming that the bottom has entered a certain depth of clay layer, such as 10-20 cm, and ensuring that a sufficiently thick soil plug has been formed, stop pressing. At this time, the sampling tube 2 contains the target sand and gravel layer sample and the bottom sealing clay layer from top to bottom. The clay at the bottom fully fills the bottom of the tube and adheres to the tube wall under pressure, forming an effective seal.

[0062] Subsequently, strictly following step five of Example 2, the vacuum machine 7 was started to establish negative pressure. At this time, the negative pressure adsorption force mainly overcomes the self-weight of the sand and gravel layer, while the bottom clay plug provides reliable sealing protection to prevent vacuum failure. Closed-loop lifting control ensures that the composite sample column is lifted out as a whole.

[0063] By transforming the sampling process from passively receiving samples at a given depth to actively creating preservation conditions for obtaining target samples, and through intelligent judgment, the device can actively penetrate the target layer to a suitable stratum below, and utilize the physical properties of the lower soil layer to provide preservation services for the target sample in the upper layer. This greatly expands the applicability and reliability of the device in difficult-to-sampling strata such as pure sand layers.

[0064] Based on the above sampling method, the specific structure of the sampling device includes a stamping mechanism 1 and a sampling tube 2. The stamping mechanism 1 is an existing soil sampler, which can adopt the drive part of a conventional hydraulic or mechanical soil sampler in the field. It has programmable controllable pressing and lifting functions. It is connected to the sampling tube 2 by a threaded connection through its drive end. The sampling tube 2 is a hollow tubular structure with an external thread or quick-connect interface at its top end. It is detachably rigidly connected to the internal thread or matching interface at the drive end of the stamping mechanism 1. This connection method can ensure that the downward pressure and lifting force are effectively transmitted to the sampling tube 2. The driving end is used to stamp the sampling tube 2, so that the sampling tube 2 enters the soil. In order to ensure that the sampling tube 2 is smoothly inserted into the soil, the bottom surface of the sampling tube 2 is tapered. The tapered design makes the cross section of the bottom end of the sampling tube 2 triangular, which can be smoothly inserted into the soil.

[0065] A solenoid valve 6, an infrared distance sensor 3, and a pressure sensor 4 are fixedly installed at the top of the sampling tube 2. The detection ends of the pressure sensor 4 and the infrared distance sensor 3 extend to the inner top of the sampling tube 2. The solenoid valve 6 is connected to the inside of the sampling tube 2. The distance between the top of the sampling tube 2 and the sampled soil is measured by the infrared distance sensor 3. The pressure sensor 4 is used to detect the air pressure inside the sampling tube 2. A controller 5 is fixedly connected to the upper surface of the stamping mechanism 1. The controller 5 integrates a programmable logic controller or an embedded processor to run the stored sampling method control program, realize data acquisition, processing, logical judgment, and motion control. The controller 5 is connected to the infrared distance sensor 3, the pressure sensor 4, and the solenoid valve 6. A vacuum machine 7 is installed on the upper surface of the stamping mechanism 1. The vacuum machine 7 is connected to the solenoid valve 6 through a pipe. The vacuum machine 7 uses the solenoid valve 6 to depressurize the inside of the sampling tube 2.

[0066] Based on the above description, the following detailed explanation is given through a specific and coherent embodiment, in conjunction with the steps in the specific implementation method: Suppose that at a certain mining exploration point, it is known that the 0 to 4 meter depth is a loose medium-coarse sand layer and the depth below 4 meter is a dense clay layer. Now it is necessary to obtain an undisturbed clay sample at a depth of 4.5 meters and accurately identify the stratigraphic interface.

[0067] Step 1: Equipment Preparation and Parameter Setting. The operator installs a 2-meter-long sampling tube onto the actuating end of the stamping mechanism, and installs an infrared distance sensor and a barometric pressure sensor at its top. After controller initialization, the sensors are calibrated, and the infrared reference distance is recorded when the tube is empty. =2.0 meters, the air pressure reading was calibrated to the local atmospheric pressure of 101.3 kPa, and then the parameters for this operation were set as follows: target sampling depth 4.5 meters, initial compression rate 20 cm / min, used to determine the curvature change threshold of the abrupt change in the formation. =0.5 .

[0068] Step 2: Sampling and Synchronous Data Acquisition. The pressing mechanism drives the sampling tube into the formation at a constant speed of 20 cm / min. Simultaneously, an infrared distance sensor measures the distance from the top of the tube to the soil surface inside the tube in real time. The system is based on the formula Calculate the actual height of soil entering the pipe. Simultaneously, the pressure sensor continuously collects the absolute air pressure P inside the pipe. During the depressurization process from 0 to 4 meters, due to the good permeability of the sand layer, some of the gas inside the pipe can be discharged. The increase is steady while P rises slowly, for example at a depth of 3 meters. ≈1.5 meters, P≈102.1 kPa.

[0069] Step 3: Real-time analysis and identification of formation characteristics and interfaces. Controller dynamic rendering. The relationship curve between P and curvature K is calculated in real time. In the sand layer section from 0 to 4 meters, the curve is approximately linear, and the curvature K value is always below 0.2. Furthermore, the fluctuations were minimal, leading the system to determine that this section was a homogeneous, high-permeability formation. When the sampling tube tip approached a depth of 4 meters, within an extremely short downward pressure distance (approximately 10 centimeters), the system detected a rapid increase in the P-value (e.g., a sudden rise from 102.5 kPa to 105.8 kPa), resulting in… With the slope of the P curve increasing sharply, the calculated curvature K value increases from 0.15 within a 0.1-meter depth interval. It increased sharply to 1.3 This far exceeds the set threshold of 0.5. The system immediately determined that it had crossed a formation interface and recorded the interface depth as 4.0 meters. At the same time, it issued an audible and visual alarm and displayed "Entering a low-permeability formation" on the operation interface.

[0070] Step 4: Sampling process adaptive adjustment based on real-time information. Based on the identified "entering cohesive strata" information, the system automatically adjusts the pressing speed of the compaction mechanism from 20 cm / min to 8 cm / min to reduce the compression and disturbance to the undisturbed cohesive soil sample. The sampling tube continues to be pressed down at a low speed to the target depth of 4.5 meters.

[0071] Step 5: Negative Pressure Adsorption and Sample Lifting. After pressing down, the system confirms that the sample is located 4.5 meters deep within the clay layer. At this point, the bottom of the sampling tube has formed a natural seal with dense clay. The controller opens the solenoid valve and starts the vacuum pump to extract gas from the top of the tube until the pressure sensor reading P drops to the preset negative pressure value of 65 kPa, at which point the valve is closed. During the lifting of the sampling tube, the controller continuously monitors the P value. Initially, the tube is lifted at a uniform speed. When slight vibrations cause the soil sample to tend to slide down during the lifting process, the volume of the sealed cavity inside the tube increases slightly, and the P value instantly rises to 68 kPa (negative pressure weakens). The controller immediately and dynamically reduces the lifting speed. After the P value stabilizes, the lifting speed is gradually restored. Through this closed-loop control centered on maintaining stable negative pressure, the complete soil sample column, containing the upper sand layer and the lower target clay layer, is finally lifted smoothly to the surface, with the sample remaining intact and without detachment.

[0072] Furthermore, if the 0-4.5 meter depth in this example consists entirely of sand, the system will determine the lack of a sealing layer based on the continuously gentle curvature after reaching the target depth. It can automatically prompt or execute a "continue pressing" command until the curvature K increases sharply, indicating the formation of an effective sealing plug in the lower clay layer. Only then will the negative pressure adsorption and closed-loop lifting process be initiated, ensuring that even pure sand samples can be reliably collected. This embodiment fully demonstrates the entire process of this invention, from data acquisition, intelligent identification, adaptive adjustment to sample preservation, showcasing its technical advantages of being data-driven, transparent, and adaptively optimized.

[0073] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0074] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A soil sampling method for mineral geological and soil exploration, characterized in that, Specifically, the following steps are included: Step 1: Equipment preparation and parameter setting. Install the sampling tube to the execution end of the stamping mechanism. Install an infrared distance sensor and a pressure sensor at the top of the sampling tube. Initialize the system, calibrate the sensors, and set the target sampling depth, initial pressing speed, and curvature change threshold. Step 2: Pressing down for sampling and simultaneous data acquisition. The pressing mechanism is controlled to press the sampling tube into the formation at a constant speed, while simultaneously acquiring data measured by an infrared distance sensor. And calculate the distance the soil penetrates into the sampling tube. And the air pressure inside the sampling tube measured by the air pressure sensor. ; Step 3: Real-time analysis and identification of stratigraphic characteristics and interfaces, based on the distance of the soil sampled into the tube in real time. air pressure inside the sampling tube Data, constructing and updating the distance of soil penetration into the sampling tube. air pressure inside the sampling tube The relationship curve is calculated, and the real-time curvature K of the curve is used to determine the formation homogeneity or identify the formation interface based on the change of curvature K. When the curvature K changes significantly, it is determined that the formation interface has been crossed and the interface depth is recorded. Step 4: Sampling process adaptive adjustment based on real-time information. After acquiring real-time formation information, the system optimizes the sampling process in real time, including the following adjustment methods: If the layer is determined to be a single homogeneous layer, continue sampling at the current pressing speed; If it is detected that the formation has entered a viscous formation, the pressing speed of the pressing mechanism will be reduced automatically or manually to reduce the disturbance to the formation. If a formation interface is identified and its depth is recorded, the system will issue an alert and can output a formation interface report after sampling is completed.

2. The soil sampling method for mineral geological and soil exploration according to claim 1, characterized in that: After sampling at the target depth, the fifth step, negative pressure adsorption and sample lifting, is performed, including establishing negative pressure and closed-loop control lifting steps. During the negative pressure establishment process, the solenoid valve is opened, the vacuum pump is started to extract the gas in the tube, and the soil at the bottom of the sampling tube is used to seal and form a negative pressure chamber until the air pressure reaches a certain level. The preset target negative pressure value has been reached, and closed-loop control is in progress, continuously monitoring the air pressure. The controller dynamically adjusts the lifting speed to maintain stable negative pressure; if a decrease in negative pressure is detected, the lifting speed is reduced.

3. The soil sampling method for mineral geological and soil exploration according to claim 1, characterized in that: In the third step, if the curvature K value remains stable during continuous downward pressure or its fluctuation is below the set threshold, the current depth segment is determined to be a single homogeneous stratum. If the curvature K value increases sharply over a short distance, it is determined to be a transition from a highly permeable stratum to a less permeable viscous stratum.

4. The soil sampling method for mineral geological and soil exploration according to claim 1, characterized in that: After identifying the entry into a viscous formation in the third step, the fourth step involves adjusting the sampling process based on real-time information, automatically or manually reducing the pressing speed of the stamping mechanism.

5. A soil sampling method for mineral geological and soil exploration according to claim 1, characterized in that: The distance the soil penetrates into the sampling tube in the second step Calculate using the following formula: ， in, This refers to the fixed distance between the infrared distance sensor detection end of the sampling tube and the bottom of the sampling tube. This refers to the real-time distance detected by the infrared distance sensor.

6. The soil sampling method for mineral geological and soil exploration according to claim 1, characterized in that: In the second step, if the system determines that the strata are all sand and gravel layers within the target sampling depth based on the continuous and gentle curvature K, then the system controls the pressing mechanism to continue pressing down the sampling tube until the curvature K increases sharply in accordance with the characteristics of cohesive strata, so that a cohesive soil plug is formed at the bottom of the sampling tube.

7. A soil sampling device for mineral geological and geotechnical exploration, used to implement the sampling method according to any one of claims 1 to 5, comprising a pressing mechanism (1) and a sampling tube (2), wherein the pressing mechanism (1) provides downward and upward power to the sampling tube (2), and the sampling tube (2) is connected to the execution end of the pressing mechanism (1) for downward sampling, characterized in that: The bottom end of the sampling tube (2) is tapered, and an infrared distance sensor (3) and a pressure sensor (4) are installed at the top end of the sampling tube (2). The sampling device also includes a controller (5), which is connected to the stamping mechanism (1), the infrared distance sensor (3) and the pressure sensor (4). The infrared distance sensor (3) is used to detect the soil surface height inside the pipe in real time. It is then transported to the controller (5); The pressure sensor (4) is used to detect the internal pressure of the sampling tube in real time. It is delivered to the controller (5); The controller (5) receives real-time data on the distance the soil penetrates into the sampling tube (2). The internal air pressure of the sampling tube (2) Construct and update the distance inside the soil deep sampling tube (2) The internal air pressure of the sampling tube (2) The relationship curve is calculated, and the real-time curvature K of the curve is used to determine the uniformity of the formation or identify the formation interface based on the change of curvature K. When the curvature K undergoes a significant change, it is determined to be a crossing of the formation interface and the interface depth is recorded. Based on the judgment result, the pressing speed of the stamping mechanism (1) is controlled or a warning message is triggered.

8. A soil sampling device for mineral geological and soil exploration according to claim 7, characterized in that: The sampling device also includes a solenoid valve (6) fixedly installed at the top of the sampling tube (2), and a vacuum machine (7) fixedly installed on the upper surface of the stamping mechanism (1). The vacuum machine (7) is connected to the solenoid valve (6) through a pipe. The suction end of the solenoid valve (6) extends to the inner top of the sampling tube (2). The solenoid valve (6) and the vacuum machine (7) are both connected to the controller (5) via signal.

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