Method and equipment for testing bearing capacity of recent hydraulic reclamation site

Abstract

The invention discloses a method and equipment for testing the bearing capacity of a recent hydraulic reclamation site, and the method comprises the steps: carrying out the surveying and mapping of the site through an unmanned plane, and obtaining a digital elevation model of the site; a plurality of detection points are set for the site according to the site digital elevation model, and the unmanned aerial vehicle measures soil layer data of each detection point of the site through a detector; and calculating the bearing capacity of each detection point according to the soil layer data of each detection point, and generating a bearing capacity distribution diagram according to the bearing capacity of each detection point. The hydraulic reclamation site is plotted through the unmanned aerial vehicle, the site bearing capacity is measured by utilizing the unmanned aerial vehicle to carry the detection equipment according to the plotting result, and the problems that an existing recent hydraulic reclamation site bearing capacity surveying method is low in efficiency and high in safety risk are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering investigation, and particularly to a method and equipment for testing the bearing capacity of a newly filled site. Background Art

[0002] In reclamation and artificial island dredging and filling projects, the "sloppy mud" formed by filling is often distributed alternately with the soft soil of the original foundation. Although the soft soil of the original foundation has a high water content, its bearing capacity can still support mechanical construction. However, the newly filled ultra-soft soil, after hydraulic remolding and particle re-selection, has not completed self-consolidation. It has a high clay content and a high content of strongly hydrophilic minerals, loose structure, and extremely high water content, resulting in extremely poor engineering properties and almost zero foundation bearing capacity. Therefore, it is necessary to carry out shallow surface rapid reinforcement treatment on the filled site to form a hard crust layer to meet the access conditions of construction equipment.

[0003] In the preliminary stage, it is necessary to divide the ultra-soft soil area and the soft soil area through the bearing capacity, and only implement shallow surface vacuum preloading reinforcement on the ultra-soft soil area. Traditional bearing capacity tests mostly rely on manual investigation, which not only has low efficiency but also has high safety risks. Summary of the Invention

[0004] To solve the above problems, the present invention provides a method and equipment for testing the bearing capacity of a newly filled site. The method uses a drone to survey the filled site and measures the bearing capacity of the site using a detection device carried by the drone according to the survey results, solving the problems of low efficiency and high safety risks in the existing methods for surveying the bearing capacity of newly filled sites.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for testing the bearing capacity of a newly filled site, comprising the following steps: S1. A drone surveys the site to obtain a digital elevation model of the site; S2. According to the digital elevation model of the site, a number of detection points are set on the site, and the drone measures the soil layer data of each detection point on the site through a detector; S3. Calculate the bearing capacity of each detection point according to the soil layer data of each detection point, and generate a bearing capacity distribution map according to the bearing capacity of each detection point.

[0006] Further, in step S1, the drone surveys the site, and its specific implementation method is as follows: A number of control points are evenly arranged in the site. For each control point, the drone navigates to the control point and collects the vertical distance between the control point and the drone and the ordinate of the drone. According to the vertical distance and the ordinate of the drone, the absolute elevation of the control point is calculated. Among them, the absolute elevation of the i-th control point , where is the error correction value, and i represents the i-th control point. represents the vertical distance between the UAV and the i-th control point when the UAV navigates to the i-th control point. is the ordinate of the UAV when the UAV navigates to the i-th control point. Obtain the absolute elevation of all control points, and generate a digital elevation model of the site using spatial interpolation based on the absolute elevation of each control point.

[0007] Furthermore, the number of control points is arranged according to the site area, and at least one control point is arranged per 1000 m 2 in the site.

[0008] Furthermore, in step S2, the UAV measures the soil layer data of each detection point in the site through a detector. The specific implementation method is as follows: for each detection point, the UAV navigates to the detection point, controls the detector to penetrate the soil layer, and the detector real-time collects the penetration depth, tip resistance, and sidewall friction resistance, and records the plane coordinates of the UAV at this time.

[0009] Furthermore, the detector is a microcone penetrometer.

[0010] Furthermore, in step S3, the bearing capacity of each detection point is calculated according to the soil layer data of each detection point. The specific implementation method is as follows: When the detector is a microcone penetrometer, the calculation formula for the bearing capacity of the detection point is:

[0011] where is the bearing capacity at the j-th detection point, k is an empirical coefficient, is the tip resistance at the j-th detection point.

[0012] Furthermore, the detector is a test element. When measuring the soil layer data of each detection point, keep the vertical distance between the UAV and the detection point as a fixed value , and the UAV releases the test element, and the test element collects the soil layer data.

[0013] Furthermore, when the detector is a test element, the calculation method for the bearing capacity of the detection point is: The calculation formula for the shear strength is:

[0014] where is the shear strength at the detection point j, To test the penetration depth of the test element at the detection point j, K is the empirical coefficient of shear strength, m is the mass of the test element, g is the acceleration due to gravity, and A is the bottom area of the test element; Then, the bearing capacity of the detection point j is calculated according to the following formula:

[0015] Among them, is the shear strength at the detection point j, c is the cohesion of the soil, is the vertical compressive stress, is the internal friction angle, 、 are bearing capacity parameters, is the bearing capacity at the detection point j.

[0016] Furthermore, in step S3, the specific implementation method of generating the bearing capacity distribution map according to the bearing capacity of each detection point is as follows: according to the bearing capacity of each detection point in the site digital elevation model, the Kriging interpolation method is used to generate the contour map of the foundation bearing capacity. Through the above technical solutions, the present invention has the following beneficial effects: The present invention uses a drone as a carrying platform, which can achieve rapid mobility and precise positioning, greatly shortening the transfer time between test points, thus significantly improving the overall test efficiency. Moreover, by using a micro cone penetration test instrument, this device can collect and transmit key parameters such as the tip resistance and sidewall friction resistance of the soil in real time, ensuring the accuracy and reliability of the test data, and providing a more accurate basis for bearing capacity evaluation. In addition, through remote operation of the drone, it effectively avoids test personnel from entering complex or dangerous geological environments, reduces potential safety risks, and guarantees the personal safety of test personnel. The overall design of the present invention is simple, the operation process is easy to master, and there is no need for complex on-site layout, which is convenient for rapid popularization and application in actual engineering. In summary, the present invention shows significant technical advantages in terms of high efficiency, precision, safety, and convenience, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the overall process schematic diagram of a method for testing the bearing capacity of a newly filled site of the present invention.

[0018] Figure 2 is the schematic diagram of generating a site digital elevation model for a method for testing the bearing capacity of a newly filled site.

[0019] Figure 3 is the schematic diagram of dividing the shallow surface vacuum preloading reinforcement area.

[0020] Figure 4Schematic structural diagram of a bearing capacity testing device for a newly filled site in an embodiment of the present invention. In the figure: 101, unmanned aerial vehicle (UAV) carrying system; 102, microcone penetrometer; 1, shock absorption suspension system; 2, UAV fuselage; 3, connection line; 4, GNSS positioning module; 5, micro double-bridge probe. Detailed implementation manners

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific implementation manners.

[0023] Refer to Figure 1 , a method for testing the bearing capacity of a newly filled site, including the following steps: S1. The UAV surveys the site to obtain a digital elevation model of the site. S2. Set a number of detection points on the site according to the digital elevation model of the site, and the UAV measures the soil layer data of each detection point on the site through a detector. S3. Calculate the bearing capacity of each detection point according to the soil layer data of each detection point, and generate a bearing capacity distribution map according to the bearing capacity of each detection point.

[0024] Specifically, determine the boundary coordinates of the site through the GNSS positioning system, plan the flight route, and control the UAV to perform aerial survey operations along the preset route.

[0025] In an optional embodiment, in step S1, the implementation manner of the UAV surveying the site is as follows: Uniformly arrange a number of control points within the site. For each control point, the UAV navigates to the control point and collects the vertical distance between the control point and the UAV and the ordinate of the UAV. Calculate the absolute elevation of the control point according to the vertical distance and the ordinate of the UAV. Among them, the absolute elevation The calculation formula is: , where is the error correction value, i represents the i-th control point, represents the vertical distance between the UAV and the i-th control point when the UAV navigates to the i-th control point, is the vertical coordinate of the UAV when it navigates to the i-th control point. Obtain the absolute elevations of all control points, and use spatial interpolation method to generate the digital elevation model of the site based on the absolute elevations of each control point.

[0026] Specifically, use the airborne LiDAR sensor to obtain the vertical distance between each point and the UAV. Based on the real-time kinematic (RTK) coordinates of the UAV ( , , ) and the vertical distance, calculate the absolute elevations of each control point of the site through spatial geometric relationships . The absolute elevation refers to the absolute height of the ground (relative to the sea level or reference plane). RTK high-precision positioning is a GNSS-based technology aimed at providing high-precision position information at the centimeter or even millimeter level. RTK technology improves the accuracy and real-time performance of positioning through differential corrections between the reference station and the rover station.

[0027] In addition, the difference in the absolute elevations Hi converted for each control point should be less than 2%. The elevation difference refers to the elevation change amount between two control points. If the absolute elevation difference is greater than 2%, it indicates that the terrain slope is steep or uneven, which may lead to the amplification of measurement errors and cause deviations in maps, terrain models or engineering designs. Therefore, 1 to 2 additional control points need to be supplemented in the site between the control points to ensure the accuracy of the absolute elevation data.

[0028] The digital elevation model (DEM) of the site is a model that digitally represents the terrain and landforms. It stores the elevation data of a location in the form of a grid or triangulated irregular network, and is used for slope analysis, flood simulation, earthwork calculation and urban planning, etc. In practical applications, through spatial interpolation method, the height of unknown locations is estimated from the absolute elevations of each control point, and a continuous terrain surface is created through methods including inverse distance weighting, Kriging or triangulated irregular network, etc., to achieve the accurate determination of the site elevation.

[0029] As Figure 2 shown, it is a schematic diagram of a specific digital elevation model of the site in the embodiment of the present invention. In the figure, the abscissa represents the east-west direction, and the ordinate represents the north-south direction. Different colors in the figure correspond to different elevations, and the elevation is the absolute elevation, with the unit of meter.

[0030] In an optional embodiment, the number of control points is arranged according to the site area, and at least one control point is arranged for every 1000 m 2 in the site.

[0031] In an alternative embodiment, in step S2, the drone measures the soil layer data of each detection point on the site through a detector. The specific implementation method is as follows: for each detection point, the drone navigates to the detection point, controls the detector to penetrate into the soil layer, and the detector real-time collects the penetration depth, tip resistance, and sidewall friction resistance, and records the plane coordinates of the drone at this time.

[0032] Specifically, the drone flies to the coordinate position of the detection point according to the preset route and monitors in real time through the on-board LiDAR sensor. At the same time, the attitude control system of the drone ensures that the platform level error is less than 0.1° to reduce measurement errors. After reaching the test conditions, the detector is automatically released. In addition, the layout density and requirements of the bearing capacity detection points shall be implemented with reference to the "Technical Regulations for Foundation Test and Detection of Water Transportation Engineering".

[0033] In an alternative embodiment, the detector is a micro static cone penetrometer. The micro static cone penetrometer (MicroStatic Cone Penetrometer, abbreviated as MSCP) is a portable engineering instrument used for on-site soil testing. It evaluates the strength, density, layer position, and bearing capacity of the soil by slowly pushing a conical probe into the soil and measuring the cone resistance and sidewall friction of the soil mass. This instrument is small in size and simple to operate, and is commonly used in shallow soil surveys, subgrade inspections, or small engineering projects.

[0034] In the specific implementation, the micro static cone penetrometer freely falls vertically under the action of gravity and penetrates into the soil layer to be measured. The system real-time records the penetration depth δ and the tip resistance of the soil mass q c and the sidewall friction resistance f s and other key parameters, and obtains the plane coordinates (Xi, Yi) of the test point through the GNSS positioning module, and synchronously transmits the coordinate data and the penetration degree parameters to the computer data processing center to provide basic data for subsequent foundation bearing capacity analysis.

[0035] In an alternative embodiment, in step S3, calculating the bearing capacity of each detection point according to the soil layer data of each detection point, the specific implementation method is as follows: When the detector is a micro static cone penetrometer, the calculation formula for the bearing capacity of the detection point is:

[0036] where is the bearing capacity at the jth detection point, k is an empirical coefficient, is the tip resistance at the jth detection point.

[0037] In an alternative embodiment, the detector is a test element. When measuring the soil layer data at each detection point, the vertical distance between the drone and the detection point is maintained at , and the drone releases the test element, which collects the soil layer data.

[0038] In the practical application of the embodiment of this solution, the test element is a standard metal body made of high-density alloy material, and the material density ρ > 2 g / cm³. A high-precision displacement sensor is integrated at the top, which can monitor and record the penetration depth δ in real time, and the measurement accuracy reaches ±0.1 mm. The overall element complies with the standard of foundation testing equipment, has good axial stiffness and bending resistance, and can ensure that no buckling deformation occurs during the testing process.

[0039] In an alternative embodiment, when the detector is a test element, the calculation method of the bearing capacity of the detection point is as follows: The calculation formula for the shear strength is:

[0040] Where, is the shear strength at the detection point j, is the vertical distance between the drone and the detection point, is the penetration depth of the test element at the detection point j, K is the shear strength empirical coefficient, m is the mass of the test element, g is the acceleration due to gravity, and A is the bottom area of the test element; Then the bearing capacity of the detection point j is calculated according to the following formula:

[0041] Where, is the shear strength at the detection point j, c is the cohesion of the soil, is the vertical compressive stress, is the internal friction angle, , are the bearing capacity parameters, is the bearing capacity at the detection point j. The actually measured value here is the ultimate bearing capacity at the detection point j, that is, the upper limit of the bearing capacity at this position, to measure the bearing force and judge whether it is suitable for foundation construction.

[0042] In an alternative embodiment, in step S3, the generation of the bearing capacity distribution map according to the bearing capacity of each detection point is specifically implemented as follows: According to the bearing capacity of each detection point in the site digital elevation model, the Kriging interpolation method is used to generate the foundation bearing capacity contour map.

[0043] Such as Figure 3As shown in the figure, the abscissa represents the east-west direction and the ordinate represents the north-south direction. Different colors in the figure correspond to different elevations. The elevation is the absolute elevation, with the unit of meter. According to the soft foundation treatment threshold specified in the specification, the GIS spatial analysis technology is used to delimit the shallow surface vacuum preloading treatment area based on the contour map of the foundation bearing capacity, determine the boundary coordinates of the treatment range, and divide the shallow surface vacuum preloading reinforcement area. The area within the red line in the figure is the shallow surface vacuum preloading reinforcement area. The treatment depth is calculated and determined according to the physical and mechanical indexes of the soil layer by the specification formula. Finally, a foundation treatment plan drawing including parameters such as geographical coordinates, treatment range, and treatment depth is formed, providing a technical basis for the drainage board layout, sealing system setting, and loading plan design of the subsequent vacuum preloading construction.

[0044] In an alternative embodiment, a multi-UAV collaborative operation system can also be adopted. By integrating the high-precision GNSS positioning technology and remote sensing sensors, rapid and efficient detection of the bearing capacity of large-area reclamation sites can be achieved.

[0045] As Figure 4 shown, in another alternative embodiment, a bearing capacity testing device for newly reclaimed sites is provided, including a UAV carrying system 101, a microcone penetrometer 102, a shock-absorbing suspension system 1, a UAV fuselage 2, a connecting line 3, a GNSS positioning module 4, and a micro double-bridge probe 5. Among them, the UAV carrying system 101 includes a memory, a processor, and a computer program stored on the memory. The processor executes the computer program to implement the steps of the bearing capacity testing method for newly reclaimed sites. The UAV fuselage 2 is equipped with a LiDAR sensor, an RTK positioning chip, an attitude control system, etc. The connecting line 3 is used to control the lifting and data transmission of the microcone penetrometer 102 or the test element. In addition, since the embodiments of the present application are for newly reclaimed sites and the soil layer strength is low, when the UAV uses the microcone penetrometer or the test element to conduct surveys at the detection points, the penetration of the soil layer can be completed by the self-weight of the equipment itself. The embodiments disclosed in this specification are only an illustration of the unilateral features of the present invention. The protection scope of the present invention is not limited to this embodiment, and any other functionally equivalent embodiments fall within the protection scope of the present invention. For those skilled in the art, various corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for testing the bearing capacity of a newly filled site, characterized in that: The following steps are involved: S1. The drone surveys the site and evenly distributes several control points in the site. For each control point, the drone navigates to the control point and collects the vertical distance between the control point and the drone and the vertical coordinate of the drone. The absolute elevation of the control point is calculated based on the vertical distance and the vertical coordinate of the drone. The absolute elevation of the i-th control point is The calculation formula is: ,in, is the error correction value, i represents the i-th control point, It indicates the vertical distance between the UAV and the i-th control point when the UAV navigates to the i-th control point. is the ordinate of the UAV when it navigates to the i-th control point, obtains the absolute elevation of all control points, generates the site digital elevation model using the spatial interpolation method according to the absolute elevation of each control point, and obtains the site digital elevation model; S2. According to the digital elevation model of the site, several detection points are set up on the site, and the drone measures the soil layer data of each detection point of the site through the detector; S3. Calculate the bearing capacity of each testing point according to the soil layer data of each testing point, and generate a bearing capacity distribution map according to the bearing capacity of each testing point.

2. A method for testing the bearing capacity of a newly filled site according to claim 1, characterized in that: The number of control points is arranged according to the site area, and every 1000m 2 Place at least one control point.

3. A method for testing the bearing capacity of a newly filled site according to claim 1, characterized in that: In step S2, the UAV measures the soil layer data of each detection point on the site through the detector. The specific implementation method is: for each detection point, the UAV navigates to the detection point and controls the detector to penetrate the soil layer. The detector collects the penetration depth, cone tip resistance and side wall friction resistance in real time, and records the plane coordinates of the UAV at this time.

4. A method for testing the bearing capacity of a newly filled site according to claim 3, characterized in that: The detector is a micro static penetration instrument.

5. A method for testing the bearing capacity of a newly filled site according to claim 3, characterized in that: In step S3, the bearing capacity of each detection point is calculated according to the soil layer data of each detection point, and the specific implementation method is as follows: When the detector is a micro static penetration instrument, the calculation formula for the bearing capacity of the detection point is: in, is the bearing capacity at the jth detection point, k is the empirical coefficient, is the cone tip resistance at the jth detection point.

6. A method for testing the bearing capacity of a newly filled site according to claim 3, characterized in that: The detector is a test element. When measuring soil layer data at each test point, the vertical distance between the drone and the test point is kept fixed. , the drone releases the test element, and the test element collects soil layer data.

7. A method for testing the bearing capacity of a newly filled site according to claim 6, characterized in that: When the detector is a test element, the bearing capacity of the test point is calculated as follows: The calculation formula for shear strength is: in, is the shear strength at the detection point j, is the vertical distance between the UAV and the detection point, is the penetration depth of the test element at the detection point j, K is the empirical coefficient of shear strength, m is the mass of the test element, g is the acceleration of gravity, and A is the bottom area of ​​the test element; The bearing capacity of the detection point j is calculated according to the following formula: in, is the shear strength at the detection point j, c is the cohesion of the soil, is the vertical compressive stress, is the internal friction angle, , is the bearing capacity parameter, is the bearing capacity at the detection point j.

8. A method for testing the bearing capacity of a newly filled site according to claim 1, characterized in that: In step S3, the bearing capacity distribution map is generated according to the bearing capacity of each detection point, and the specific implementation method is: according to the bearing capacity of each detection point in the site digital elevation model, the foundation bearing capacity contour map is generated by using the Kriging interpolation method.

9. A device, characterized in that: The system at least comprises a processor and a memory, wherein the processor calls computer instructions in the memory to execute the bearing capacity testing method for a newly filled site as claimed in any one of claims 1 to 8.

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