IMU (Inertial Measurement Unit)-based pile hole perpendicularity measurement method and system

Abstract

The invention discloses an IMU (Inertial Measurement Unit)-based pile hole perpendicularity measurement method and system, and the method comprises the steps: arranging an IMU at the tail end of a drill rod, and enabling the IMU to extend downwards to the bottom of a pile hole along with a drilling tool; attitude information of the drilling tool in the downward exploration process is obtained through an attitude calculation algorithm, and power head rotation angle data and downward exploration depth data are fused; calculating horizontal projection changes of the axis of the pile hole in the front-back direction and the left-right direction on the basis of attitude changes under unit depth, and obtaining a space deviation track of the whole pile hole in an integration mode to realize evaluation of the perpendicularity of the pile hole; the system comprises an IMU (Inertial Measurement Unit), a main roll sounding sensor, a power head rotation angle sensor and an intelligent terminal. According to the invention, pile hole perpendicularity short-period measurement can be realized, pile hole deflection can be found in time, the problem of measurement lag is solved, and the pile foundation construction quality and efficiency are improved.

Description

Technical Field

[0001] This invention belongs to the field of pile foundation construction technology, specifically relating to an IMU-based method and system for measuring the verticality of pile holes. Background Technology

[0002] In modern infrastructure construction, rotary drilling and long spiral drilling cast-in-place piles have become the main pile-forming techniques widely used in pile foundation engineering due to their high construction efficiency and stable pile quality. As a crucial foundation for bearing the loads of the superstructure, the quality of pile hole formation directly affects the overall functionality, stability, and safety of the building. Among these factors, the verticality deviation of the pile hole is one of the key factors affecting critical indicators such as the bearing capacity of a single pile, the synergistic effect of pile groups, and eccentric stress on the structure.

[0003] In actual construction, due to various factors such as uneven strata, uneven drilling stress, improper operation, and the structure of the drilling rig itself, both rotary cast-in-place piles and long spiral cast-in-place piles are susceptible to risks of pile hole tilting and axis deviation. The problem of pile hole verticality deviation is particularly prominent in soft foundations, high-fill areas, or complex geological conditions. If not properly controlled, it will seriously affect the project quality and subsequent structural safety.

[0004] Currently, in the construction of rotary drilling and long spiral drilling cast-in-place piles, the control of pile hole verticality still mainly relies on manual measurement or post-drilling inspection methods. These methods suffer from problems such as long measurement cycles, poor real-time performance, and accuracy dependent on manual operation, making it difficult to detect tilting deviations that occur during drilling in a timely manner. Among them, the commonly used ultrasonic measurement method can usually only be implemented after the hole is cleaned, which is not suitable for frequent short-cycle measurements in the same pile hole and has a lag effect.

[0005] Therefore, how to achieve short-cycle measurement of pile hole verticality, detect pile hole deviation in a timely manner, and solve the problem of measurement lag is a technical issue that needs to be studied by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an IMU-based method and system for measuring the verticality of pile holes, which can realize short-cycle measurement of pile hole verticality, detect pile hole deviation in a timely manner, solve the problem of measurement lag, and improve the quality and efficiency of pile foundation construction.

[0007] To achieve the above objectives, the present invention provides an IMU-based method for measuring the verticality of pile holes, comprising the following steps:

[0008] S1 and IMU are installed using a base mounting method, secured with bolts, and mounted at the end of the drill pipe;

[0009] S2. Zero the measurement system, zero the IMU attitude angle data, and zero the drill depth data. The IMU attitude angle includes pitch angle, roll angle, and yaw angle.

[0010] S3, trigger the start measurement signal, and the IMU and smart terminal synchronize timing;

[0011] S4. Perform measurements. Operate the drill bit to descend to the bottom of the hole at a certain lowering and rotation speed. The IMU continuously measures and stores attitude angle data throughout the descent process, and then lifts it to the ground.

[0012] The intelligent terminal simultaneously measures and records the power head rotation angle data, drill string depth data, and sampling time;

[0013] S5. Measurement data transmission: When the IMU reaches the ground, it automatically uploads the attitude angle data during the descent to the smart terminal.

[0014] S6. Data synchronization: Through software time synchronization algorithm, the attitude angle data obtained above are synchronized with the power head rotation angle data and drill depth data to obtain the measurement values ​​of different data sources at the same time.

[0015] S7. Calculation of pile hole verticality deviation and deviation azimuth angle;

[0016] S8. Pile type visualization: Based on the data calculated in S7, draw the curve of horizontal offset versus depth, and draw a top view of the pile hole offset direction angle.

[0017] As a further solution of the present invention: S7 The calculation of the verticality deviation and deviation azimuth angle of the pile hole is specifically as follows: establish the coordinate system of the drilling rig body, wherein the left and right direction of the drilling rig is defined as the X-axis, the front and back direction is defined as the Y-axis, and the vertical downward direction is defined as the Z-axis.

[0018] Attitude angle information based on IMU measurements, including pitch angle θ and roll angle The unit direction vector of the current borehole axis in three-dimensional space is obtained by conversion;

[0019] Project the unit direction vector onto the horizontal plane and decompose it into the X and Y directions respectively, and calculate the horizontal offset per unit depth.

[0020] The horizontal offset of the i-th segment along the X-axis: dx i =tan(θ) x,i )·Δz;

[0021] The horizontal offset of the i-th segment along the Y-axis: dy i =tan(θ) y,i )·Δz;

[0022] Where, θx,i θ is the inclination angle of the pile hole axis in the X direction at the i-th segment. y,i Δz is the tilt angle of the i-th segment in the Y-axis direction, and Δz is the depth increment of each segment, i.e., per unit depth.

[0023] Cumulative deviation in the X direction:

[0024] Cumulative deviation in the Y direction:

[0025] Where N is the number of discrete segments of the pile hole depth;

[0026] Total horizontal offset:

[0027] Pile hole deviation azimuth angle:

[0028] As a further aspect of the present invention: the IMU of the rotary drilling rig is installed at the plug position at the end of the drill rod, and its installation direction satisfies the following relationship: the X-axis and Y-axis are parallel to the ground, and the Z-axis is perpendicular to the ground and consistent with the direction of the drill rod axis.

[0029] As a further aspect of the present invention: the IMU of the long spiral drilling rig is installed on the surface of the spiral blade at the lower end of the long spiral drill rod, and its installation direction satisfies the following relationship: the X-axis points to the center of the drill rod, the Y-axis is parallel to the local tangent direction of the blade, and the Z-axis is perpendicular to the contact surface.

[0030] As a further aspect of the present invention: the smart terminal includes a processor and a memory, the memory pre-stores a computer program for implementing a method for measuring the verticality of pile holes, which can be loaded and executed by the processor.

[0031] To achieve the above objectives, the present invention also provides an IMU-based pile hole verticality measurement system for implementing the aforementioned IMU-based pile hole verticality measurement method, comprising:

[0032] An IMU, installed at the end of the drill pipe, is used to measure and record the motion and attitude information of the drill bit during the descent process in real time, so as to reflect the spatial changes of the pile hole axis.

[0033] The main roll depth sounder is used to acquire depth data of the IMU in real time during the descent process, and provides a longitudinal reference for calculating the position of the pile hole axis;

[0034] A power head rotation angle sensor is used to enable the IMU to identify the azimuth or rotation angle during the measurement process;

[0035] The intelligent terminal is used to realize the acquisition and fusion of multi-sensor data, the calculation of pile hole axis and the evaluation of verticality, the visualization of measurement results, and the interactive control of the measurement process.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] 1. By operating the drill rod equipped with an IMU to descend to the bottom of the hole, the verticality of the pile hole is calculated using the motion attitude of the IMU. The measurement is quick and convenient, and the verticality of the pile hole can be measured in near real time.

[0038] 2. By establishing a coordinate system for the drilling rig body, the actual axis space of the pile hole is modeled, and the verticality deviation and trajectory change of the actual pile hole are presented intuitively, realizing the visualization of the pile type and providing a basis for on-site construction adjustments and quality assessment.

[0039] 3. This invention can be widely applied to different pile-forming methods such as rotary drilling and long spiral drilling, and is also applicable to various hole-forming processes such as dry hole and wet hole, and has good versatility and engineering adaptability. Attached Figure Description

[0040] Figure 1 This is a flowchart of the pile hole verticality measurement method of the present invention;

[0041] Figure 2 This is a schematic diagram of the IMU installation of the rotary drilling rig of this invention;

[0042] Figure 3 This is a schematic diagram of the installation of the long spiral drilling rig IMU of the present invention, wherein Figure (a) is a side view of the installation and Figure (b) is a top view of the installation;

[0043] Figure 4 This is a schematic diagram illustrating the calculation of pile hole deviation displacement and azimuth angle according to the present invention;

[0044] Figure 5 This is a visualization diagram of the verticality of the pile hole according to the present invention; wherein, Figure (a) is a top view of the pile hole, representing the azimuth angle of the pile hole deviation, and Figure (b) is a side view of the pile hole, where Depth is the depth and Offset is the offset;

[0045] Figure 6 This is a block diagram illustrating the principle of the pile hole verticality measurement system of the present invention.

[0046] In the diagram: 2-1, drill bucket; 2-2, drill rod square head; 2-3, IMU (Inertial Measurement Unit);

[0047] 3-1. Long spiral drill pipe; 3-2. Spiral blades; 3-3. IMU (Inertial Measurement Unit). Detailed Implementation

[0048] The invention will now be further described with reference to the accompanying drawings.

[0049] like Figure 1 As shown, an IMU-based method for measuring the verticality of pile holes includes the following steps:

[0050] S1, IMU (Inertial Measurement Unit) installation: It adopts a base mounting method and is fixed to the end of the drill rod with bolts;

[0051] Example 1, IMU installation method for rotary drilling rigs: as follows Figure 2 As shown, it is installed at the end of the square head of the drill pipe, and its installation direction satisfies the following relationship: the X-axis and Y-axis are parallel to the ground, and the Z-axis is perpendicular to the ground and consistent with the direction of the drill pipe axis.

[0052] Example 2, IMU installation method for long spiral drilling rig: as follows Figure 3 As shown, the spiral blades installed on the lower end of the long spiral drill pipe have the following installation directions: the X-axis points to the center of the drill pipe, the Y-axis is parallel to the local tangent direction of the blade (i.e., the tangent direction of the blade contact surface), and the Z-axis is perpendicular to the contact surface.

[0053] The IMU is connected to the drill rod using a base mounting method. The mounting base has sufficient thickness and structural support. The IMU is fixed by bolts and locating pins to ensure a rigid and reliable connection, while also meeting the requirements for quick assembly and disassembly.

[0054] S2. Zero the measurement system. Under the condition that the drill rod is vertical, operate the drill to rotate at a constant speed. Zero the IMU attitude angle data through the operation intelligent terminal, operate the drill to the ground position, and clear the drill depth data. The IMU attitude angle includes pitch angle θ, roll angle φ, and yaw angle ψ.

[0055] S3. Trigger the start measurement signal. After completing the zeroing preparation, trigger the start measurement signal by operating the smart terminal. The smart terminal sends the start measurement signal to the IMU via wireless communication. The IMU and the smart terminal start timing synchronously.

[0056] S4. Perform measurements. Operate the drill bit to descend to the bottom of the hole at a certain lowering and rotation speed. The IMU continuously measures and stores attitude angle data throughout the descent process, and then lifts it to the ground.

[0057] The intelligent terminal simultaneously measures and records the power head rotation angle data, drill string depth data, and sampling time;

[0058] S5. Measurement data transmission: When the IMU reaches the ground, it automatically uploads the attitude angle data during the descent to the smart terminal.

[0059] S6. Data synchronization: Through software time synchronization algorithm, the attitude angle data obtained above are synchronized with the power head rotation angle data and drill depth data to obtain the measurement values ​​of different data sources at the same time.

[0060] S7. Calculation of pile hole verticality deviation and deviation azimuth angle;

[0061] Specifically, taking the structure of the rotary drilling rig itself as a reference, such as... Figure 4 As shown, a coordinate system for the drilling rig body is established, where the left and right directions of the drilling rig's movement are defined as the X-axis, the forward and backward directions are defined as the Y-axis, and the vertical downward direction is defined as the Z-axis.

[0062] Based on the attitude angle information measured by the IMU, the pitch angle θ and roll angle φ are converted into the unit direction vector of the current borehole axis in three-dimensional space.

[0063] Project the unit direction vector onto the horizontal plane and decompose it into the X and Y directions respectively, and calculate the horizontal offset per unit depth.

[0064] The horizontal offset of the i-th segment along the X-axis: dx i =tan(θ) x,i )·Δz;

[0065] The horizontal offset of the i-th segment along the Y-axis: dy i =tan(θ) y,i )·Δz;

[0066] Where, θ x,i θ is the inclination angle of the pile hole axis in the X direction at the i-th segment. y,i Δz is the tilt angle of the i-th segment in the Y-axis direction, and Δz is the depth increment of each segment, i.e., per unit depth.

[0067] Cumulative deviation in the X direction:

[0068] Cumulative deviation in the Y direction:

[0069] Where N is the number of discrete segments of the pile hole depth;

[0070] Total horizontal offset:

[0071] Pile hole deviation azimuth angle:

[0072] S8, Pile type visualization, such as Figure 5 As shown, the curves relating the horizontal offset to the depth in the X / Y axis directions are plotted based on the data calculated by S7, and a top view of the pile hole offset direction angle is drawn to represent the pile hole offset azimuth angle.

[0073] Furthermore, the smart terminal includes a processor and a memory, with the memory pre-stored a computer program for implementing the pile hole verticality measurement method, which can be loaded and executed by the processor.

[0074] Memory is a computer-readable storage medium, including: USB flash drive, portable hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, and other media that can store program code.

[0075] like Figure 6 As shown, an IMU-based pile hole verticality measurement system is used to implement the aforementioned IMU-based pile hole verticality measurement method, comprising:

[0076] An IMU, installed at the end of the drill pipe, is used to measure and record the motion and attitude information of the drill bit during the descent process in real time, so as to reflect the spatial changes of the pile hole axis.

[0077] The main roll depth sounder is used to acquire depth data of the IMU in real time during the descent process, and provides a longitudinal reference for calculating the position of the pile hole axis;

[0078] A power head rotation angle sensor is used to enable the IMU to identify the azimuth or rotation angle during the measurement process;

[0079] The intelligent terminal is used to realize the acquisition and fusion of multi-sensor data, the calculation of pile hole axis and the evaluation of verticality, the visualization of measurement results, and the interactive control of the measurement process.

[0080] With the above system configuration, IMU attitude angle data and depth data are collected and measured during the drilling process. Combined with the power head rotation angle information, the projected coordinates of the pile hole axis in the horizontal X / Y direction are calculated, and then the horizontal offset of the pile hole and its offset azimuth angle are obtained, realizing real-time and accurate measurement of the verticality of the pile hole, thereby significantly improving the accuracy of measurement and work efficiency.

Claims

1. A method for measuring the verticality of pile holes based on IMU, characterized in that, Includes the following steps: S1 and IMU are installed using a base mounting method, secured with bolts, and mounted at the end of the drill pipe; S2. Zero the measurement system, zero the IMU attitude angle data, and zero the drill depth data. The IMU attitude angle includes pitch angle, roll angle, and yaw angle. S3, trigger the start measurement signal, and the IMU and smart terminal synchronize timing; S4. Perform measurements. Operate the drill bit to descend to the bottom of the hole at a certain lowering and rotation speed. The IMU continuously measures and stores attitude angle data throughout the descent process, and then lifts it to the ground. The intelligent terminal simultaneously measures and records the power head rotation angle data, drill string depth data, and sampling time; S5. Measurement data transmission: When the IMU reaches the ground, it automatically uploads the attitude angle data during the descent to the smart terminal. S6. Data synchronization: Through software time synchronization algorithm, the attitude angle data obtained above are synchronized with the power head rotation angle data and drill depth data to obtain the measurement values ​​of different data sources at the same time. S7. Calculation of pile hole verticality deviation and deviation azimuth angle; S8. Pile type visualization: Based on the data calculated in S7, draw the curve of horizontal offset versus depth, and draw a top view of the pile hole offset direction angle.

2. The method for measuring the verticality of pile holes based on IMU according to claim 1, characterized in that, The calculation of the verticality deviation and deviation azimuth angle of the S7 pile hole is as follows: establish the coordinate system of the drilling rig body, in which the left and right direction of the drilling rig is defined as the X-axis, the front and back direction is defined as the Y-axis, and the vertical downward direction is defined as the Z-axis. Attitude angle information based on IMU measurements, including pitch angle θ and roll angle The unit direction vector of the current borehole axis in three-dimensional space is obtained by conversion; Project the unit direction vector onto the horizontal plane and decompose it into the X and Y directions respectively, and calculate the horizontal offset per unit depth. The horizontal offset of the i-th segment along the X-axis: dx i =tan(θ) x,i )·Δz; The horizontal offset of the i-th segment along the Y-axis: dy i =tan(θ) y,i )·Δz; Where, θ x,i θ is the inclination angle of the pile hole axis in the X direction at the i-th segment. y,i Δz is the tilt angle of the i-th segment in the Y-axis direction, and Δz is the depth increment of each segment, i.e., per unit depth. Cumulative deviation in the X direction: Cumulative deviation in the Y direction: Where N is the number of discrete segments of the pile hole depth; Total horizontal offset: Pile hole deviation azimuth angle:

3. A method for measuring the verticality of pile holes based on an IMU according to claim 1 or 2, characterized in that, The IMU installation method for rotary drilling rigs is as follows: it is installed at the plug position at the end of the drill rod, and its installation direction meets the following relationship: the X-axis and Y-axis are parallel to the ground, and the Z-axis is perpendicular to the ground and consistent with the axis of the drill rod.

4. A method for measuring the verticality of pile holes based on an IMU according to claim 1 or 2, characterized in that, The IMU installation method for long spiral drilling rigs is as follows: it is installed on the surface of the spiral blade at the lower end of the long spiral drill rod, and its installation direction satisfies the following relationship: the X-axis points to the center of the drill rod, the Y-axis is parallel to the local tangent direction of the blade, and the Z-axis is perpendicular to the contact surface.

5. A method for measuring the verticality of pile holes based on an IMU according to claim 1 or 2, characterized in that, The smart terminal includes a processor and a memory. The memory contains a computer program that can be loaded and executed by the processor to implement the method for measuring the verticality of pile holes.

6. An IMU-based pile hole verticality measurement system, used to implement the IMU-based pile hole verticality measurement method according to any one of claims 1-5, characterized in that, include: An IMU, installed at the end of the drill pipe, is used to measure and record the motion and attitude information of the drill bit during the descent process in real time, so as to reflect the spatial changes of the pile hole axis. The main roll depth sounder is used to acquire depth data of the IMU in real time during the descent process, and provides a longitudinal reference for calculating the position of the pile hole axis; A power head rotation angle sensor is used to enable the IMU to identify the azimuth or rotation angle during the measurement process; The intelligent terminal is used to realize the acquisition and fusion of multi-sensor data, the calculation of pile hole axis and the evaluation of verticality, the visualization of measurement results, and the interactive control of the measurement process.

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