Static sounding device and method

Abstract

The application discloses a static sounding test device, comprising: a hyperspectral assembly and a static sounding assembly; the hyperspectral assembly comprises a fiber group, an integrated lens and an optical window, and the fiber group comprises a light source, a heat dissipation assembly, a coupling lens group, an emitting optical fiber and a receiving optical fiber array; the static sounding assembly comprises a signal transmission cable, a friction sleeve sensor, a friction sleeve, an inclinometer, a cone tip, a pressure sensor and a cone tip resistance sensor; the fiber group transmits spectral data to an external host computer, and the signal transmission cable transmits side friction resistance, cone tip resistance and pore water pressure to the external host computer. The application further discloses a method for performing static sounding test by using the static sounding test device. The static sounding test device has the advantages that the hyperspectral assembly is small in size and small in occupied tangential area, the spectral assembly does not need to be internally provided with a power supply, the structure of the static sounding test device and the internal light path are relatively simple, the manufacturing difficulty is relatively low, and the production cost is greatly reduced.

Description

Technical Field

[0001] This invention relates to the fields of optoelectronics and marine engineering, and specifically to a static cone penetration test apparatus and test method. Background Technology

[0002] Static cone penetration tests can evaluate the mechanical properties of different soil layers and classify soil layers mechanically. The static cone penetration test uses static pressure to press a conical probe into the soil at a certain rate. The end resistance, side friction, and pore water pressure experienced by the conical probe during penetration are measured to determine the mechanical properties of the soil layer. However, it is difficult to obtain information on the mineral composition of seabed soil layers through static cone penetration tests, and it is not possible to accurately classify soil layers.

[0003] To address the aforementioned technical issues, Chinese invention patent publication CN108827909A proposes a static cone penetration test device and method based on hyperspectral imaging technology, which can acquire hyperspectral images simultaneously when measuring end resistance and side friction. However, this device contains numerous hyperspectral imaging components and requires a power supply installed inside the probe, resulting in a large size. In contrast, the actual diameter of a static cone penetration test device is relatively small, approximately 4 cm, thus limiting its practicality. Furthermore, hyperspectral imaging technology generates a very large amount of data and involves complex data processing to meet the demands of high-precision spectral and spatial analysis. Moreover, hyperspectral imaging equipment is expensive, while delineating complex soil layers only requires acquiring spectral data. Therefore, using existing hyperspectral imaging equipment for soil layer delineation is neither economical nor practical.

[0004] Hyperspectral non-imaging technology acquires one-dimensional continuous spectral curve data point-by-point or line-by-line using single-point detectors or linear array detectors combined with spectroscopic elements. Hyperspectral non-imaging technology does not require complex imaging techniques, resulting in relatively simple system structure and hardware requirements, making it easy to integrate with static cone penetration testing (CPPT) devices. Spectral data acquired through hyperspectral non-imaging technology can be used to estimate soil particle composition, and its relatively simple structure and hardware requirements make it more economical and feasible. However, there are currently no reports of applying hyperspectral non-imaging technology to static cone penetration testing devices.

[0005] Furthermore, existing static cone penetration tests rely on empirical formulas to stratify soil layers based on data trends, making it difficult to directly identify soil layer types. For soil layers with gradually changing physical and mechanical properties, it's challenging to accurately determine the stratification boundaries. Thin soil layers, with a thickness less than the probe diameter, are difficult to delineate because they are not clearly reflected on the curve. In marine environments, weakly cemented layers or calcareous sands and silts are common, and due to their unique mechanical behavior, they are easily misclassified as dense sand or bedrock. Moreover, for onshore static cone penetration tests, water level is a crucial reference for stratification. Traditional static cone penetration tests indirectly infer the static water level through pore water pressure, but the presence of excess pore water pressure makes it difficult to accurately determine the initial static water level. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a compact, economical, and practical static cone penetration test device based on the principle of hyperspectral non-imaging mineral analysis. This invention also provides a static cone penetration test method, utilizing spectral data, side friction, cone tip resistance, and pore water pressure measured by the static cone penetration test device to delineate complex soil layers.

[0007] Therefore, the present invention adopts the following technical solution:

[0008] A static cone penetration test apparatus includes: a probe, a hyperspectral component, and a static cone penetration component; wherein:

[0009] The main body of the probe is a hollow cylinder without a bottom surface. Four equally spaced openings of equal size are provided on the circumference of the probe near the bottom for installing an optical window.

[0010] The hyperspectral components are installed inside the probe and near its bottom. There are four hyperspectral components, each including one fiber optic group, one integrated lens, and one optical window. Each fiber optic group includes a light source, a heat dissipation component, a coupling lens group, a transmitting fiber, and a receiving fiber array. The light source emits spatial light; the heat dissipation component blocks the heat generated by the light source; the coupling lens group performs spatial light-to-fiber mode conversion on the spatial light emitted by the light source; the transmitting fiber receives the beam in fiber mode output by the coupling lens group and transmits the received beam to the integrated lens, which then illuminates the soil; the receiving fiber array receives the reflected beam from the soil and consists of six receiving fibers.

[0011] The integrated lens is used to collimate the beam output from the fiber optic group into a parallel beam and focus the parallel beam through the optical window to illuminate the soil.

[0012] The optical window is used to protect the integrated lens and fiber optic assembly from external environmental influences.

[0013] The static cone penetration test assembly is used to measure side friction, cone tip resistance, and pore water pressure.

[0014] The optical fiber group transmits spectral data to the external host, and the static cone penetration test component transmits side friction, cone tip resistance and pore water pressure to the external host through a signal transmission cable, which is then analyzed and processed by the external host.

[0015] The static cone penetration test assembly includes: a signal transmission cable, a friction sleeve sensor, a friction sleeve, an inclinometer, a cone tip, a pressure sensor, a cone tip resistance sensor, and a sealing ring; wherein:

[0016] The friction sleeve sensor is used to measure the lateral friction resistance experienced by the static cone penetration test device when penetrating the soil. The friction sleeve sensor is ring-shaped. The friction sleeve is a hollow circular tube, and its outer diameter is consistent with the maximum diameter of the cone tip. The inclinometer is used to detect the verticality of the probe and provide inclination data to correct for the resistance, lateral friction resistance, and penetration depth of the probe tip. The cone tip is a solid cone. The pressure sensor is used to measure the pore water pressure. The cone tip resistance sensor is used to measure the cone tip resistance experienced by the cone tip. The cone tip resistance sensor is ring-shaped. The lateral friction resistance, cone tip resistance, and pore water pressure measured by the friction sleeve sensor, pressure sensor, and cone tip resistance sensor are transmitted to the external host via a signal transmission cable through a microcircuit signal.

[0017] In the static cone penetration test assembly, one end of the friction sleeve is fixedly connected to the end of the probe near the bottom surface, and a sealing ring is installed at the interface; the other end of the friction sleeve is fixedly connected to the circular surface of the cone tip, and a sealing ring is installed at the interface; a hollow inner tube is fixedly installed in the hollow position inside the friction sleeve, and the outer wall of the hollow inner tube is not completely fitted with the inner wall of the friction sleeve, leaving a first annular groove and a second annular groove. The friction sleeve sensor is located in the second annular groove and is fixed on the outer wall of the hollow inner tube; the cone tip resistance sensor is located in the first annular groove and is fixed on the outer wall of the hollow inner tube; the inclinometer is located in the middle of the cavity of the hollow inner tube, and the inclinometer is connected to the end of the signal transmission cable, the other end of the signal transmission cable is connected to an external host; the pressure sensor is located at the bottom of the cavity of the hollow inner tube and near the cone tip; the friction sleeve sensor, the pressure sensor, and the cone tip resistance sensor are all connected to the signal transmission cable; sealing rings installed in multiple locations are used to prevent liquid from entering the interior of the static cone penetration test device.

[0018] In each fiber optic group, a heat dissipation component is attached to the surface of the light source. The light source and the coupling lens group are kept at a certain distance. The coupling lens group is located at the center inside the outer sheath of the fiber optic group. The coupling lens group is connected to the transmitting fiber, which is located at the center inside the outer sheath of the fiber optic group. The receiving fiber array is located inside the outer sheath. The six receiving fibers of the receiving fiber array are evenly distributed in a circumferential direction with the transmitting fiber as the center.

[0019] In the hyperspectral component, four optical windows are located at the four openings of the probe rod and are flush with the outer wall of the probe rod. An integrated lens is provided between the optical windows and the optical fiber group. The integrated lens and the optical windows maintain a fixed distance. The position of the optical fiber group is fixed by a fixing ring so that when using the static penetration test device, the spatial light emitted by the light source travels according to the preset optical path, receives the reflected beam of the soil from the optical fiber array, and transmits it to the external host.

[0020] A method for conducting a static cone penetration test using the aforementioned static cone penetration test apparatus includes the following steps:

[0021] S1, measuring spectral data, side friction, cone tip resistance, and pore water pressure:

[0022] The static cone penetration test device is pressed into the soil layer, and the penetration depth at the cone tip is recorded in real time. And spectral data; the cone tip resistance, the lateral frictional resistance of the friction sleeve, and the pore water pressure in the soil are measured using a cone tip resistance sensor, a friction sleeve sensor, and a pressure sensor;

[0023] S2, Corrected Penetration Depth Cone tip resistance Side friction resistance The corrected penetration depth was obtained. Cone tip resistance and side friction resistance ;

[0024] S3, based on cone tip resistance Side friction resistance and pore water pressure With the corrected penetration depth The change relationship curve of the soil mass is used to roughly divide the soil mass into layers, and the rough stratification result of the soil mass is obtained.

[0025] S4. Based on the rough stratification results of the soil obtained in S3, and combined with the changes in spectral data collected near the strata, verify the accuracy of the rough stratification results and perform precise stratification of the soil layers to obtain the precise stratification results of the soil. Based on the precise stratification results of the soil layers, divide the spectral data at different depths obtained in S1 into multiple sets according to soil type, calculate the arithmetic mean of the spectral data in each set, and obtain the initial spectral data of different soil layers.

[0026] S5, after removing the edge bands with low signal-to-noise ratio from the initial spectral data of different soil layers, noise elimination and outlier detection processing are performed; then, by eliminating spectral baseline shift and tilt, preprocessed spectral data is obtained.

[0027] S6, obtain the final soil stratification results:

[0028] S6-1: Collect the underwater infrared spectral curves of common minerals in seabed soil, determine the characteristic wavelengths, and establish the correlation between near-infrared spectral absorption characteristics and mineral chemical composition.

[0029] S6-2, Based on the correlation relationship obtained in S6-1, establish an inversion model, input the preprocessed spectral data obtained in S5 into the inversion model, and extract the spectral features corresponding to the preprocessed spectral data;

[0030] S6-3 inputs the preprocessed spectral data and its corresponding spectral features into the trained classification model to determine the soil type and obtain the final soil stratification result. The final soil stratification result includes the soil type and corresponding depth range of each soil layer, realizing comprehensive stratification of the soil in the vertical direction.

[0031] In the above technical solution, the following operations are performed before step S1: calibrate the fixed position of the fiber optic port and the distance between the integrated lens and the optical window in the static penetration test device; calibrate the accuracy of the cone tip resistance sensor, friction sleeve sensor, and pressure sensor; check whether the sealing ring is intact; connect and fix the static penetration test device and the penetration device in sequence; check the verticality of the static penetration test device; and conduct a preliminary test in a nearby site.

[0032] In step S5 of the above technical solution, the edge bands include 350-400 nm and 2451-255 nm; noise cancellation and outlier detection are performed using Savitzky-Golay filtering; and multivariate scattering correction technology is used to eliminate spectral baseline shift and tilt.

[0033] In step S6-2 of the above technical solution, the inversion model is established using partial least squares regression modeling. The spectral features include: clay content, organic carbon content, and content.

[0034] In step S6-3 of the above technical solution, the classification model is constructed using a one-dimensional convolutional neural network. The one-dimensional convolutional neural network includes: one input layer and three dilated convolutional layers connected in sequence. The kernel size of each dilated convolutional layer is 5×1, 3×1, and 3×1, respectively. The number of kernels in the three dilated convolutional layers is 64, the stride is 1, the dilation rate is 2, and the activation function is ReLU. The classification model is trained using a mapping relationship to obtain the trained classification model. The mapping relationship is constructed based on the preprocessed spectral data described in S5 and a standard spectral database of known soil types.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The static cone penetration test device of the present invention adds a hyperspectral component to the ordinary static cone penetration test device. The hyperspectral component is small in size and occupies a small tangential area, making it more suitable for narrow static cone penetration test devices. The spectral component does not require a built-in power supply, further saving internal space of the device.

[0037] 2. The forward optical path of the static cone penetration test device of the present invention is light source - coupling lens group - transmitting optical fiber - integrated lens - optical window - soil, and the reverse optical path is soil reflection - optical window - integrated lens - receiving optical fiber array - spectrometer main body (host). The structure and internal light path of the entire static cone penetration test device are relatively simple, the manufacturing difficulty is relatively low, and the production cost is greatly reduced.

[0038] 3. The static cone penetration test method of the present invention can analyze spectral data and cone tip resistance. Side friction resistance and pore water pressure A comprehensive analysis is conducted, and the spectral features of the preprocessed spectral data are extracted through an inversion model. Then, a classification model is used to determine the soil type based on the preprocessed spectral data and its corresponding spectral features, resulting in the final soil stratification result, thereby achieving the division of complex soil layers. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the static cone penetration test apparatus according to an embodiment of the present invention;

[0040] Figure 2 for Figure 1 A schematic diagram of the internal structure of the optical fiber assembly in a static penetration test apparatus;

[0041] Figure 3 This is a diagram showing the distribution of the transmitting and receiving fiber arrays in the static penetration test apparatus of the present invention.

[0042] Figure 4 This is a flowchart of the static cone penetration test method of the present invention;

[0043] Figure 5 This is a graph showing the relationship between cone tip resistance, side friction resistance, pore water pressure and modified penetration depth in one embodiment of the present invention.

[0044] Figure 6 This is the final soil stratification result in one embodiment of the present invention.

[0045] In the picture:

[0046] 1. Hyperspectral component, 2. Signal transmission cable, 3. Friction sleeve sensor, 4. Friction sleeve, 5. Inclinometer, 6. Cone tip, 7. Pressure sensor, 8. Cone tip resistance sensor, 9. Sealing ring, 10. Probe, 11. Optical window, 12. Integrated lens, 13. Fiber optic assembly, 131. Transmitting fiber, 132. Receiving fiber array, 133. Coupling lens assembly, 134. Light source, 135. Heat dissipation assembly, 14. Fixing ring, 15. Hollow inner tube, 16. First annular groove, 17. Second annular groove. Detailed Implementation

[0047] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0048] Example 1

[0049] like Figure 1 As shown, a static cone penetration test apparatus according to an embodiment of the present invention includes: a probe 10, a hyperspectral component 1, and a static cone penetration component. Wherein:

[0050] The main body of the probe rod 10 is a hollow cylinder without a bottom surface. Four equally spaced openings of equal size are provided on the circumference of the probe rod near the bottom for installing the optical window 11.

[0051] The hyperspectral component 1 is installed inside the probe 10 and near the bottom of the probe. There are four hyperspectral components 1, each including: one fiber optic group 13, one integrated lens 12, and one optical window 11. Wherein:

[0052] See Figure 2 Each fiber optic group 13 includes: a light source 134, a heat dissipation assembly 135, a coupling lens group 133, a transmitting fiber 131, and a receiving fiber optic array 132. Wherein:

[0053] The light source 134 is used to emit spatial light;

[0054] The heat dissipation component 135 includes heat dissipation fins and a heat insulation layer. The heat dissipation component 135 is used to block the heat generated by the light source 134 and prevent thermal deformation of the coupling lens group 133.

[0055] The coupling lens group 133 is used to perform spatial light-to-fiber mode conversion on the spatial light emitted by the light source 134; the base of the coupling lens group is made of a material with a low coefficient of thermal expansion (CTE) to suppress mechanical deformation caused by temperature changes and thus ensure the accuracy of spectral measurement.

[0056] The transmitting optical fiber 131 is used to receive the optical fiber mode beam output by the coupling lens group 133, and transmit the received beam to the integrated lens 12, thereby illuminating the soil.

[0057] The receiving fiber array 132 is used to receive the reflected light beam from the soil, such as Figure 3 As shown, the receiving fiber array 132 consists of six receiving fibers.

[0058] In each fiber optic group 13, a heat dissipation component 135 is attached to the surface of a light source 134. The light source 134 is kept at a certain distance from the coupling lens group 133. The coupling lens group 133 is located at the center of the inner sheath of the fiber optic group. The coupling lens group 133 is connected to the transmitting fiber 131, which is located at the center of the inner sheath of the fiber optic group. The receiving fiber array 132 is located inside the outer sheath. The six receiving fibers of the receiving fiber array 132 are evenly distributed in a circumferential direction with the transmitting fiber as the center.

[0059] The integrated lens 12 is a plano-convex lens. The integrated lens 12 is used to collimate the beam output by the fiber optic group 13 into a parallel beam and focus the parallel beam through the optical window 11 to illuminate the soil.

[0060] The optical window 11 is used to protect the integrated lens 12 and the fiber optic assembly 13 from the influence of the external environment. The optical window 11 has high light transmittance and high mechanical strength. The optical window 11 is made of sapphire material. Anti-reflection coatings are provided on both the inner and outer surfaces of the optical window to improve transmittance and reduce the loss of reflected light beams.

[0061] In this embodiment, the integrated lens 12 is a fiber collimating lens of brand name LS-FOL or a fiber focusing lens of brand name LS-MC manufactured by LiSen Optics; the fiber optic assembly 13 is an ASD fiber manufactured by Malvern Panalytical.

[0062] In the hyperspectral component 1, four optical windows 11 are located at the four openings of the probe rod and are flush with the outer wall of the probe rod. An integrated lens 12 is provided between the optical windows 11 and the fiber optic assembly 13, and a fixed distance is maintained between the integrated lens 12 and the optical windows 11. The position of the fiber optic assembly 13 is fixed by a retaining ring 14 so that when using the static cone penetration test device, the spatial light emitted by the light source 134 travels along a preset optical path. The receiving fiber array receives the reflected beam of the soil and transmits it to the external host.

[0063] The static cone penetration test assembly includes: a signal transmission cable 2, a friction sleeve sensor 3, a friction sleeve 4, an inclinometer 5, a cone tip 6, a pressure sensor 7, a cone tip resistance sensor 8, and a sealing ring 9.

[0064] Among them, the friction sleeve sensor 3 is used to measure the lateral friction resistance experienced by the static penetration test device when penetrating the soil. The friction sleeve sensor 3 is annular; the friction sleeve 4 is a hollow circular tube, and the outer diameter of the friction sleeve 4 is consistent with the maximum diameter of the cone tip 6. Figure 1The diameter of the cylindrical surface at the top of the cone tip); the inclinometer 5 is used to detect the verticality of the probe and provide inclination data to correct the resistance, side friction resistance and penetration depth of the cone tip 6; the cone tip 6 is a solid cone; the pressure sensor 7 is used to measure the pore water pressure; the cone tip resistance sensor 8 is used to measure the cone tip resistance, and the cone tip resistance sensor 8 is annular; the side friction resistance, cone tip resistance and pore water pressure measured by the friction sleeve sensor 3, the pressure sensor 7 and the cone tip resistance sensor 8 are transmitted to the external host via the signal transmission cable 2 through the microcircuit signal.

[0065] In the static penetration test assembly, one end of the friction sleeve 4 is fixedly connected to the end of the probe 10 near the bottom surface, and a sealing ring 9 is installed at the interface; the other end of the friction sleeve 4 is fixedly connected to the circular surface of the cone tip 6, and a sealing ring 9 is installed at the interface; the hollow inner tube 15 is fixedly installed in the hollow position inside the friction sleeve 4, and the outer wall of the hollow inner tube 15 is not completely fitted with the inner wall of the friction sleeve 4, leaving a first annular groove 16 and a second annular groove 17. The friction sleeve sensor 3 is located in the second annular groove and is fixed on the outer wall of the hollow inner tube; the cone tip resistance sensor 8 is located in the first annular groove and is fixed on the outer wall of the hollow inner tube; the inclinometer 5 is located in the middle of the cavity of the hollow inner tube, and the inclinometer 5 is connected to the end of the signal transmission cable 2, the other end of the signal transmission cable 2 is connected to the external host; the pressure sensor 7 is located at the bottom of the cavity of the hollow inner tube and near the cone tip 6; the friction sleeve sensor 3, the pressure sensor 7 and the cone tip resistance sensor 8 are all connected to the signal transmission cable 2. The sealing rings 9 installed in multiple locations are used to prevent liquid from entering the static cone penetration test device.

[0066] In the static cone penetration test apparatus, the optical fiber group 13 transmits spectral data to the external host, and the signal transmission cable 2 transmits the side friction resistance, cone tip resistance and pore water pressure to the external host, which then performs data analysis and processing.

[0067] The cone angle, cone base cross-sectional area, and surface area of ​​the friction sleeve 4 of cone tip 6 all meet the requirements of GB / T 50267-2018 Static cone penetration test technical standard, ISO 22476-1 Geotechnical Engineering Investigation Specification and ASTM D5775-20.

[0068] Example 2

[0069] See Figure 4 A method for conducting a static cone penetration test using the static cone penetration test apparatus of Example 1 according to the present invention includes the following steps:

[0070] S1, Calibrate and calibrate the static cone penetration test apparatus:

[0071] Calibrate the fixed position of the fiber optic port in the static cone penetration test apparatus; calibrate the distance between the integrated lens and the optical window in the static cone penetration test apparatus; calibrate the accuracy of the cone tip resistance sensor, friction sleeve sensor, and pressure sensor; check whether the sealing ring is intact so that the pressure sensor after saturation is not affected by air bubbles.

[0072] S2, Construct the static cone penetration test apparatus:

[0073] Connect and fix the static cone penetration test device and the penetration equipment in sequence, check the verticality of the static cone penetration test device, and conduct a preliminary test in the nearby site.

[0074] S3, measuring spectral data, side friction, cone tip resistance, and pore water pressure:

[0075] The static cone penetration test device is pressed into the soil layer using a penetration test equipment, and the penetration depth of the cone tip of the static cone penetration test device is recorded in real time. The system transmits the spectral data acquired by the receiving fiber optic array to the host in real time. It measures the cone tip resistance, lateral frictional resistance of the friction sleeve, and pore water pressure in the soil during the penetration process using a cone tip resistance sensor, friction sleeve sensor, and pressure sensor. The measured lateral frictional resistance, cone tip resistance, and pore water pressure are transmitted to the external host via a signal transmission cable.

[0076] During the process of the static cone penetration test device penetrating the soil, the spatial light emitted by the light source in the static cone penetration test device is converted into a beam in fiber optic mode through the coupling lens group. The beam enters the transmitting fiber, and the light emitted by the transmitting fiber passes through the integrated lens and is collimated into a parallel beam. The parallel beam passes through the optical window and enters the soil, and is reflected on the soil. The reflected light passes through the optical window and the integrated lens and is transmitted to the receiving fiber array and then to the external host.

[0077] In one embodiment of the present invention, spectral data is recorded every 5 centimeters during the process of penetrating the static cone penetration test device into the soil.

[0078] S4, Corrected Penetration Depth Cone tip resistance Side friction resistance The calculation formulas are as follows:

[0079]

[0080] In the formula, The corrected penetration depth. For penetration depth; This is the penetration length of the probe. This is the tilt correction factor.

[0081]

[0082] In the formula, This is the corrected cone tip resistance; The measured cone tip resistance; The pore water pressure at the cone shoulder location; This refers to the effective area ratio. It is the ratio of the cross-sectional area of ​​the pressure sensor to the cross-sectional area of ​​the surface containing the maximum diameter of the cone tip.

[0083]

[0084] In the formula, This is the corrected side friction resistance; The measured side friction resistance; The surface area of ​​the friction sleeve; This is the cross-sectional area of ​​the top of the friction sleeve; This is the cross-sectional area of ​​the bottom surface of the friction sleeve; This refers to the pore water pressure at the tail end of the friction sleeve.

[0085] S5, roughly stratify the soil:

[0086] Based on cone tip resistance Side friction resistance and pore water pressure With the corrected penetration depth The variation curves are used to roughly stratify the soil, resulting in a rough stratification result.

[0087] Among them, cone tip resistance Side friction resistance and pore water pressure With the corrected penetration depth A schematic diagram of the relationship curve is shown below. Figure 5 As shown.

[0088] S6, precise stratification of the soil:

[0089] The wavelength-reflectance images collected from soils of the same type are similar. Based on the rough stratification results of the soil obtained in S5, and combined with the changes in spectral data collected near the stratification, the accuracy of the rough stratification results is verified and the soil layers are precisely stratified to obtain the precise stratification results of the soil.

[0090] Based on the precise soil layer division results, the spectral data at different depths obtained by S3 are divided into multiple sets according to soil type. The arithmetic mean of the spectral data in each set is calculated to obtain the initial spectral data of different soil layers.

[0091] S7, Spectral Data Preprocessing:

[0092] After removing the low signal-to-noise ratio edge bands 350-400 and 2451-255nm from the initial spectral data, Savitzky-Golay filtering is used for noise reduction and outlier detection.

[0093] The calculation formula for noise cancellation is as follows:

[0094]

[0095] in, and These are the spectral values ​​of wavelength m after smoothing and denoising, and the original spectral value, respectively, where n is the size of the smoothing window. It is the convolution coefficient corresponding to the wavelength (m+p), and the unit of wavelength is nm.

[0096] The spectral baseline shift and tilt caused by scattering from soil particles are then eliminated using multivariate scattering correction technology to obtain preprocessed spectral data. The calculation formula for multivariate scattering correction technology is as follows:

[0097]

[0098] in, The original spectral vector, The corrected spectral vector, is an additive shift, and b is a multiplicative factor.

[0099] S8, obtain the final soil stratification results:

[0100] While existing experimental data such as the optical fingerprint database of substances are applicable to terrestrial environments, considering the absorption and scattering of spectra by water, underwater spectral data acquisition is necessary. This involves collecting underwater infrared spectral curves of common minerals in seabed soil layers, determining characteristic wavelengths, and establishing the correlation between near-infrared spectral absorption characteristics and mineral chemical composition.

[0101] S8-2, based on the correlation relationship obtained in S8-1, uses the Partial Least Squares Regression (PLSR) modeling method to establish an inversion model. The preprocessed spectral data obtained in S7 is input into the inversion model to extract the spectral features corresponding to the preprocessed spectral data. The spectral features include: clay content, organic carbon content, and... content.

[0102] S8-3: Due to the complex composition and poor spectral stability of the soil, the spectral data preprocessed in S7 and its corresponding spectral features are input into the trained classification model to determine the soil type and obtain the final soil stratification result. The final soil stratification result includes the soil type and corresponding depth range of each soil layer, realizing comprehensive stratification of the soil in the vertical direction.

[0103] The classification model is constructed using a one-dimensional convolutional neural network. A mapping relationship is established between the preprocessed spectral data described in S7 and a standard spectral database of known soil types. The classification model is trained using this mapping relationship to obtain the trained classification model.

[0104] In one embodiment of the present invention, a schematic diagram of the final soil stratification result is shown below. Figure 6 As shown, the one-dimensional convolutional neural network includes: one input layer and three dilated convolutional layers connected in sequence. The kernel size of each dilated convolutional layer is 5×1, 3×1 and 3×1, respectively. The number of kernels in the three dilated convolutional layers is 64, the stride is 1, the dilation rate is 2, and the activation function is ReLU.

Claims

1. A static cone penetration test apparatus, characterized in that, include: Probe rod, hyperspectral module, and static cone penetration test module; among which: The main body of the probe is a hollow cylinder without a bottom surface. Four equally spaced openings of equal size are provided on the circumference of the probe near the bottom for installing an optical window. The hyperspectral components are installed inside the probe and near its bottom. There are four hyperspectral components, each including one fiber optic group, one integrated lens, and one optical window. Each fiber optic group includes a light source, a heat dissipation component, a coupling lens group, a transmitting fiber, and a receiving fiber array. The light source emits spatial light; the heat dissipation component blocks the heat generated by the light source; the coupling lens group performs spatial light-to-fiber mode conversion on the spatial light emitted by the light source; the transmitting fiber receives the beam in fiber mode output by the coupling lens group and transmits the received beam to the integrated lens, which then illuminates the soil; the receiving fiber array receives the reflected beam from the soil and consists of six receiving fibers. The integrated lens is used to collimate the beam output from the fiber optic group into a parallel beam and focus the parallel beam through the optical window to illuminate the soil. The optical window is used to protect the integrated lens and fiber optic assembly from external environmental influences. The static cone penetration test assembly is used to measure side friction, cone tip resistance, and pore water pressure. The optical fiber group transmits spectral data to the external host, and the static cone penetration component transmits side friction, cone tip resistance and pore water pressure to the external host through a signal transmission cable, which is then analyzed and processed by the external host. The static cone penetration test assembly includes: a signal transmission cable, a friction sleeve sensor, a friction sleeve, an inclinometer, a cone tip, a pressure sensor, a cone tip resistance sensor, and a sealing ring; wherein: The friction sleeve sensor is used to measure the lateral friction resistance experienced by the static cone penetration test device when penetrating the soil. The friction sleeve sensor is ring-shaped. The friction sleeve is a hollow circular tube, and its outer diameter is consistent with the maximum diameter of the cone tip. The inclinometer is used to detect the verticality of the probe and provide inclination data to correct for the resistance, lateral friction resistance, and penetration depth of the probe tip. The cone tip is a solid cone. The pressure sensor is used to measure the pore water pressure. The cone tip resistance sensor is used to measure the cone tip resistance experienced by the cone tip. The cone tip resistance sensor is ring-shaped. The lateral friction resistance, cone tip resistance, and pore water pressure measured by the friction sleeve sensor, pressure sensor, and cone tip resistance sensor are transmitted to the external host via a signal transmission cable through a microcircuit signal. In each fiber optic group, a heat dissipation component is attached to the surface of the light source. The light source and the coupling lens group are kept at a certain distance. The coupling lens group is located at the center inside the outer sheath of the fiber optic group. The coupling lens group is connected to the transmitting fiber, which is located at the center inside the outer sheath of the fiber optic group. The receiving fiber array is located inside the outer sheath. The six receiving fibers of the receiving fiber array are evenly distributed in a circumferential direction with the transmitting fiber as the center. In the hyperspectral component, four optical windows are located at the four openings of the probe rod and are flush with the outer wall of the probe rod. An integrated lens is provided between the optical windows and the optical fiber group. The integrated lens and the optical windows maintain a fixed distance. The position of the optical fiber group is fixed by a fixing ring so that when using the static penetration test device, the spatial light emitted by the light source travels according to the preset optical path, receives the reflected beam of the soil from the optical fiber array, and transmits it to the external host.

2. The static cone penetration test apparatus according to claim 1, characterized in that: In the static cone penetration test assembly, one end of the friction sleeve is fixedly connected to the end of the probe near the bottom surface, and a sealing ring is installed at the interface; the other end of the friction sleeve is fixedly connected to the circular surface of the cone tip, and a sealing ring is installed at the interface; a hollow inner tube is fixedly installed in the hollow position inside the friction sleeve, and the outer wall of the hollow inner tube is not completely fitted with the inner wall of the friction sleeve, leaving a first annular groove and a second annular groove. The friction sleeve sensor is located in the second annular groove and is fixed on the outer wall of the hollow inner tube; the cone tip resistance sensor is located in the first annular groove and is fixed on the outer wall of the hollow inner tube; the inclinometer is located in the middle of the cavity of the hollow inner tube, and the inclinometer is connected to the end of the signal transmission cable, the other end of the signal transmission cable is connected to an external host; the pressure sensor is located at the bottom of the cavity of the hollow inner tube and near the cone tip; the friction sleeve sensor, the pressure sensor, and the cone tip resistance sensor are all connected to the signal transmission cable; sealing rings installed in multiple locations are used to prevent liquid from entering the interior of the static cone penetration test device.

3. A method for conducting a static cone penetration test using the static cone penetration test apparatus according to claim 2, characterized in that, Includes the following steps: S1, measuring spectral data, side friction, cone tip resistance, and pore water pressure: The static cone penetration test device is pressed into the soil layer, and the penetration depth at the cone tip is recorded in real time. And spectral data; the cone tip resistance, the lateral frictional resistance of the friction sleeve, and the pore water pressure in the soil are measured using a cone tip resistance sensor, a friction sleeve sensor, and a pressure sensor; S2, Corrected Penetration Depth Cone tip resistance Side friction resistance The corrected penetration depth was obtained. Cone tip resistance and side friction resistance ; S3, based on cone tip resistance Side friction resistance and pore water pressure With the corrected penetration depth The change relationship curve of the soil mass is used to roughly divide the soil mass into layers, and the rough stratification result of the soil mass is obtained. S4. Based on the rough stratification results of the soil obtained in S3, and combined with the changes in spectral data collected near the strata, the accuracy of the rough stratification results is verified and the soil layers are precisely divided to obtain the precise stratification results of the soil. Based on the precise stratification results of the soil, the spectral data at different depths obtained in S1 are divided into multiple sets according to soil type, and the arithmetic mean of the spectral data in each set is calculated to obtain the initial spectral data of different soil layers. S5, after removing the edge bands with low signal-to-noise ratio from the initial spectral data of different soil layers, noise elimination and outlier detection processing are performed; then, by eliminating spectral baseline shift and tilt, preprocessed spectral data is obtained. S6, obtain the final soil stratification results: S6-1: Collect the underwater infrared spectral curves of common minerals in seabed soil, determine the characteristic wavelengths, and establish the correlation between near-infrared spectral absorption characteristics and mineral chemical composition. S6-2, Based on the correlation relationship obtained in S6-1, establish an inversion model, input the preprocessed spectral data obtained in S5 into the inversion model, and extract the spectral features corresponding to the preprocessed spectral data; S6-3 inputs the preprocessed spectral data and its corresponding spectral features into the trained classification model to determine the soil type and obtain the final soil stratification result. The final soil stratification result includes the soil type and corresponding depth range of each soil layer, realizing comprehensive stratification of the soil in the vertical direction.

4. The method according to claim 3, characterized in that, Before proceeding to step S1, the following steps are also performed: Calibrate the fixed position of the fiber optic port and the distance between the integrated lens and the optical window in the static penetration test device; calibrate the accuracy of the cone tip resistance sensor, friction sleeve sensor, and pressure sensor; and check whether the sealing ring is intact. Connect and fix the static cone penetration test device and the penetration equipment in sequence, check the verticality of the static cone penetration test device, and conduct a preliminary test in the nearby site.

5. The method according to claim 4, characterized in that: In step S6-2, the inversion model is established using partial least squares regression modeling. The spectral features include: clay content, organic carbon content, and... content.

6. The method according to claim 5, characterized in that: In step S6-3, the classification model is constructed using a one-dimensional convolutional neural network, which includes: one input layer and three dilated convolutional layers connected in sequence. The kernel sizes of each dilated convolutional layer are 5×1, 3×1, and 3×1, respectively. The number of kernels in each of the three dilated convolutional layers is 64, the stride is 1, the dilation rate is 2, and the activation function is ReLU. The classification model is trained using a mapping relationship to obtain the trained classification model. The mapping relationship is constructed based on the preprocessed spectral data described in S5 and a standard spectral database of known soil types.

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