Method for measuring cast-in-situ bored pile center deviation based on three-point circle method

Abstract

The invention relates to the field of civil engineering automatic monitoring, and discloses a method for measuring cast-in-situ bored pile center deviation based on a three-point circle method.The method comprises the steps that the initial pose of an integrated frame installed on the pile top is accurately calculated through external equipment such as a total station, an internal tilt angle sensor is calibrated, and during real-time monitoring, the initial pose of the integrated frame is accurately calculated; the three-point coordinates on the contour of the circular target object are obtained through the three non-collinear laser distance measuring sensors in the frame, the relative position vector of the center of the circular target object relative to the frame is solved in real time through the three-point circle method, attitude compensation operation is conducted on the relative position vector, the attitude compensation is converted into a global coordinate system, and finally the attitude compensation is conducted through the initial translation vector. The real-time absolute coordinates of the target object are synthesized, and high-precision deviation monitoring is achieved. According to the method, initial calibration and real-time compensation are combined, errors caused by inclination of a monitoring reference are effectively eliminated, and the real-time performance, the automation degree and the data reliability of pile foundation construction deviation monitoring are improved.

Description

Technical Field

[0001] This invention relates to the field of automated monitoring technology in civil engineering, and in particular to a method for measuring the core deviation of bored cast-in-place piles based on the three-point circle method. Background Technology

[0002] As a core load-bearing structure in modern building and bridge engineering, the construction quality of pile foundations directly affects the stability and long-term safety of the entire structure. During pile foundation construction, precise and continuous monitoring of the pile center's position at key stages such as drilling, lowering the reinforcing cage, and concrete pouring is crucial to ensuring that the pile foundation construction quality meets design requirements.

[0003] Currently, the industry commonly uses geodetic instruments such as total stations to measure coordinates by setting up observation points near the pile location and directly or indirectly aiming at the pile core or temporary markers, thereby controlling and verifying pile position deviation. However, in actual construction, this traditional measurement method has limitations. On the one hand, because the construction process is dynamic and continuous, traditional methods require surveyors to repeatedly set up stations, aim, and measure at different construction nodes. This measurement mode, which relies on continuous manual intervention, is not only discontinuous and inefficient, but also increases the workload of on-site surveyors, making it impossible to achieve automated and uninterrupted tracking of the pile core position.

[0004] Furthermore, pile foundation construction sites are typically complex environments, with mud and water often present near the pile borehole openings, slippery surfaces, and frequent movement of large machinery. Traditional surveying methods require surveyors to operate at close range to the pile borehole, exposing workers to a high-risk working environment for extended periods, posing a potential threat to their safety.

[0005] More importantly, vibrations at the construction site, disturbances to the surrounding soil, and uneven settlement of the steel casing itself under stress can cause minute, unpredictable displacements and tilts in the reference points used for measurement or the platforms on which the measuring equipment is installed. Traditional measurement methods typically treat the measurement reference as an ideal, stable, fixed point, making it impossible to perceive and quantify changes in the reference's own attitude. Therefore, when the measurement reference tilts, the errors introduced by this attitude change are directly transmitted to the final measurement results, leading to distortion of the pile core coordinate data and severely affecting the reliability and accuracy of the measurement results. Summary of the Invention

[0006] The purpose of this invention is to provide a method for measuring the core deviation of bored piles based on the three-point circle method, which solves the problems of high measurement frequency, dangerous work required for measurement personnel at the pile hole opening, and low measurement accuracy due to irregular measurement targets or unstable measurement benchmarks in existing methods for measuring the core deviation of bored piles.

[0007] To achieve the above object, the present application is realized by the following technical solutions: The present application provides a method for measuring the pile core deviation of a cast-in-place bored pile based on a three-point circle method, comprising the following steps: S1, providing and installing an integrated multi-stage measurement calibration frame on a steel casing at a pile position, wherein the integrated multi-stage measurement calibration frame is integrated with an external absolute reference system, an internal relative measurement system and an internal attitude sensing system; S2, measuring the external absolute reference system to solve the initial attitude and initial absolute coordinates of the integrated multi-stage measurement calibration frame in a global coordinate system; S3, calibrating the internal attitude sensing system according to the initial attitude solved in the S2 step to determine the calibration offset; S4, during construction, obtaining the coordinates of three spatial points on the target object profile through the internal relative measurement system, solving the three-dimensional relative position vector of the target object center by the three-point circle method, and obtaining the real-time attitude of the integrated multi-stage measurement calibration frame through the internal attitude sensing system; S5, performing attitude compensation operation on the three-dimensional relative position vector according to the real-time attitude obtained in the S4 step and the calibration offset determined in the S3 step to obtain a three-dimensional relative displacement vector; S6, superimposing the horizontal component of the three-dimensional relative displacement vector obtained in the S5 step and the horizontal component of the initial absolute coordinates solved in the S2 step to obtain the final absolute horizontal coordinates of the target object center, and comparing with the designed pile core coordinates to determine the pile core deviation.

[0008] Preferably, the external absolute reference system comprises three prism points, which are fixedly connected to the top of the integrated multi-stage measurement calibration frame.

[0009] Preferably, in the S2 step, the measurement of the external absolute reference system is performed by measuring the three-dimensional coordinates of the three prism points in the global coordinate system through a total station.

[0010] Preferably, in the S1 step, the internal relative measurement system comprises three laser ranging sensors arranged in a non-collinear manner, which are fixedly connected to the inner side wall of the integrated multi-stage measurement calibration frame.

[0011] Preferably, in the S1 step, the internal attitude sensing system comprises a dual-axis tilt sensor, which is fixedly connected to the inner side wall of the integrated multi-stage measurement calibration frame.

[0012] Preferably, in the S2 step, the initial attitude comprises an initial pitch angle and an initial roll angle of the integrated multi-order measurement calibration frame.

[0013] Preferably, the S5 step is specifically: calculating a corrected real-time absolute attitude by using the real-time attitude obtained in the S4 step and the calibration offset determined in the S3 step; and constructing a real-time rotation matrix according to the corrected real-time absolute attitude, and performing coordinate transformation on the three-dimensional relative position vector by using the real-time rotation matrix to obtain a three-dimensional relative displacement vector.

[0014] The corrected real-time absolute attitude is calculated by the following formula: β(t)=φ raw (t)+Offset β ; α(t)=θ raw (t)+Offset α ; Wherein: β(t) is a real-time absolute roll angle of the integrated multi-order measurement calibration frame at time t; α(t) is a real-time absolute pitch angle of the integrated multi-order measurement calibration frame at time t; φ raw (t) is a roll angle original reading of the dual-axis tilt sensor at time t; θ raw (t) is a pitch angle original reading of the dual-axis tilt sensor at time t; Offset β is the calibration offset in the roll angle direction; Offset α is the calibration offset in the pitch angle direction.

[0015] The coordinate transformation is realized by the following formula: Wherein: ΔC g (t) is the three-dimensional relative displacement vector, which is a spatial displacement of the target object center relative to the origin of the integrated multi-order measurement calibration frame in the global coordinate system; R(t) is the real-time rotation matrix constructed according to the real-time absolute attitude α(t) and β(t); C fvec (t) is the three-dimensional relative position vector of the target object center in the frame coordinate system of the integrated multi-order measurement calibration frame.

[0016] Preferably, in the S4 step, the target is selected from the group consisting of a drill pipe with a circular cross-section and a reinforcement cage.

[0017] Preferably, the method further comprises the step of comparing the size of the pile core deviation with a preset threshold value, and triggering an alarm signal when the size of the pile core deviation exceeds the preset threshold value.

[0018] Preferably, the preset threshold value is set according to at least one selected from the group consisting of a designed pile diameter of the pile foundation to be measured and a related building pile detection technical specification.

[0019] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application installs an integrated multi-stage measurement calibration frame on the pile position steel casing, which can be automatically and continuously monitored by the internal system after completing the external absolute calibration once, replacing the repeated manual measurement during the whole construction process, and reducing the measurement operation frequency and workload.

[0020] 2. After the initial calibration of the integrated multi-stage measurement calibration frame is completed by the measurement personnel in the safe area away from the pile hole, the subsequent measurement is completed by the frame itself, avoiding close-range operation by the measurement personnel in the slippery and dangerous pile hole, and improving the safety of construction measurement.

[0021] 3. The internal attitude perception system integrated in the integrated multi-stage measurement calibration frame can obtain the attitude change of the frame caused by construction disturbance in real time, and perform dynamic compensation operation on the data of the internal relative measurement system, eliminating the error introduced by unstable measurement reference, and ensuring the reliability of the final pile core coordinate data. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a perspective view of the present application; Figure 2 is a whole flow chart of the pile foundation construction deviation real-time monitoring and attitude compensation method of the present application; Figure 3 is a field installation and coordinate system relationship schematic diagram of the integrated multi-stage measurement calibration frame of the present application; Figure 4 is a principle schematic diagram of external calibration and initial parameter calculation of the present application.

[0023] Among them, 1, integrated multi-stage measurement calibration frame; 2, prism point; 3, laser ranging sensor; 4, two-axis inclination sensor; 5, target. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the specification of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0025] Reference is made to the accompanying drawings Figure 1 , Figure 1 The present application provides a method for measuring the pile core deviation of a cast-in-place bored pile based on a three-point circle method. The implementation of the method relies on a measurement system with an integrated multi-stage measurement calibration framework 1 as the core carrier. The integrated multi-stage measurement calibration framework 1 physically integrates the external absolute calibration reference with the internal dynamic measurement sensor, forming an independent measurement unit that can operate autonomously after initial calibration.

[0026] The integrated multi-stage measurement calibration framework 1 is a rigid circular hollow structure made of materials with high rigidity and low thermal deformation coefficient. Its overall structure remains stable in the construction environment, ensuring that the relative spatial positions and attitudes between the prism point 2, the laser ranging sensor 3, and the dual-axis tilt sensor 4 remain constant.

[0027] The external absolute reference system is composed of three prism points 2 fixed on the top of the integrated multi-stage measurement calibration framework 1. The three prism points 2 are distributed in a non-collinear space on the top of the integrated multi-stage measurement calibration framework 1. This layout allows the three-dimensional coordinate measurement of the three prism points 2 by an external total station to uniquely determine the spatial six-degree-of-freedom pose of the integrated multi-stage measurement calibration framework 1 in the global coordinate system S g , including three-dimensional position and three-dimensional attitude.

[0028] The internal relative measurement system includes three laser ranging sensors 3, which are fixedly installed on the inner side wall of the integrated multi-stage measurement calibration framework 1. The three laser ranging sensors 3 are arranged in a non-collinear space on the inner wall of the integrated multi-stage measurement calibration framework 1, and their respective laser emission directions are directed to the center area of the framework. In operation, the three laser ranging sensors 3 measure and output the real-time distances and

[0029] The internal attitude perception system includes a dual-axis tilt sensor 4, which is fixedly installed on the inner side wall of the integrated multi-stage measurement calibration framework 1. The two sensitive axes of the dual-axis tilt sensor 4 are used to measure the rotation angles of the integrated multi-stage measurement calibration framework 1 around the frame coordinate system S fthe rotation angles of the x-axis and y-axis of the two-axis tilt sensor 4. In operation, the two-axis tilt sensor 4 measures and outputs the roll angle raw reading φ raw (t) and the pitch angle raw reading θ raw (t) in real time.

[0030] To accurately describe the spatial position, attitude and transformation relationship involved in the present application, two coordinate systems are established and used in the present embodiment, namely a global coordinate system S g and a frame coordinate system S f .

[0031] The global coordinate system S g is a fixed absolute coordinate system, which is usually the engineering coordinate system unified in the construction site. The design coordinates of all pile foundations, the observation data of external measuring equipment and the final calculated pile center deviation results are all expressed in this coordinate system. The coordinates of any point in the global coordinate system S g are represented by a three-dimensional coordinate vector (X, Y, Z).

[0032] The frame coordinate system S f is a local coordinate system fixed on the integrated multi-stage measurement calibration frame 1 and moves with the integrated multi-stage measurement calibration frame 1. The coordinate origin O f is defined at the geometric center of the integrated multi-stage measurement calibration frame 1, and the directions of the x, y and y axes are uniquely determined by the mechanical structure of the frame and form a right-handed coordinate system. The precise positions and directional attitudes of the internal integrated sensors, including the laser ranging sensor 3 and the two-axis tilt sensor 4, in the frame coordinate system S f are determined through pre-laboratory calibration. All raw data directly measured by the internal relative measurement system and the internal attitude sensing system are initially expressed in the frame coordinate system S f . The coordinates of any point in the frame coordinate system S f are represented by a three-dimensional coordinate vector (x, y, z).

[0033] The spatial transformation relationship between the frame coordinate system S f and the global coordinate system S g can be described by a rotation matrix R and a translation vector T. The coordinate vectors of any physical point in the two coordinate systems have the following rigid body transformation relationship: P g = R·P f + T. Wherein: P g is the coordinate vector of any point in the global coordinate system S g , which is in the form of (X, Y, Z); P fFor the same point in the frame coordinate system S f The coordinate vector in the vector is of the form (x, y, z); R is the frame coordinate system S f Relative to the global coordinate system S g The rotation matrix; T is the frame coordinate system S f Origin f In the global coordinate system S g The coordinate vector in the coordinate system, also known as the translation vector, is used to describe the relative position between the origins of two coordinate systems.

[0034] Reference Appendix Figure 2 , Figure 2 This is an overall flowchart of the real-time monitoring and attitude compensation method for pile foundation construction deviation according to the present invention. The measurement method of the present invention mainly includes two stages: the initial calibration stage and the real-time monitoring and calculation stage. The initial calibration stage includes steps S1 to S3, which aims to accurately obtain the initial parameters of the system; the real-time monitoring and calculation stage includes steps S4 to S6, which aims to dynamically and accurately track the coordinates of the target object 5 during the construction process.

[0035] Reference Appendix Figure 3 , Figure 3 This is a schematic diagram showing the on-site installation and coordinate system relationship of the integrated multi-stage measurement calibration frame of the present invention. The specific implementation of the method of the present invention begins with step S1, that is, the integrated multi-stage measurement calibration frame 1 is placed on the steel casing at the top of the pile location.

[0036] Before installation, the top surface of the steel casing must be cleaned to remove mud, debris, and other adhering substances, providing a flat and clean contact surface. Subsequently, the integrated multi-stage measurement calibration frame 1 is hoisted or transported to the top of the steel casing, and its position is adjusted so that the geometric center of the integrated multi-stage measurement calibration frame 1 is approximately aligned with the center of the steel casing on the horizontal plane. This alignment operation aims to ensure that the target object 5 (such as a drill rod or rebar cage) during subsequent construction falls within the effective measurement range of the three laser rangefinders 3.

[0037] After the integrated multi-stage measurement calibration frame 1 is positioned correctly, it is rigidly connected to the steel casing using a fastening device. The fastening device can be a mechanical clamp, bolted connector, or a dedicated connecting seat welded to the outer wall of the steel casing. The purpose of this connection is to ensure that there is no relative displacement or rotation between the integrated multi-stage measurement calibration frame 1 and the steel casing. This stable connection is the physical basis for all subsequent measurement steps, ensuring the stability of the integrated multi-stage measurement calibration frame 1 as a measurement reference.

[0038] When fastening the integrated multi-stage measurement and calibration frame 1, its initial orientation can be determined, thus obtaining the frame coordinate system S. fThe x-axis and y-axis directions of the local coordinate system S g are approximately parallel to the principal axis directions (e.g. the north and east directions) of the global coordinate system S g . This operation is not a precision requirement, but helps to simplify the initial verification and interpretation of subsequent data. After installation and fixation is completed, physical inspection is required to confirm that the integrated multi-order measurement calibration frame 1 will not shake due to vibration or accidental touching on the construction site.

[0039] Reference is made to the accompanying drawings Figure 4 , Figure 4 , which are incorporated herein by reference in their entirety. The accompanying drawings illustrate the principles of the external calibration and initial parameter solving of the present application. After the installation and fixation of the integrated multi-order measurement calibration frame 1 is completed, step S2 is performed. The purpose of step S2 is to accurately solve the initial pose of the integrated multi-order measurement calibration frame 1 in the global coordinate system S g , i.e. to determine the rotation matrix R0 and the translation vector T0 at the initial time.

[0040] First, the total station is erected at a stable position on the construction site, and the three prism points 2 at the top of the integrated multi-order measurement calibration frame 1 are observed one by one under the global coordinate system S g . Through observation, the three-dimensional coordinates of each prism point 2 in the global coordinate system S g are obtained. The coordinate vectors of the three prism points 2 are denoted as p g,1 , p g,2 , and p g,3 , respectively. At the same time, the coordinates of the three prism points 2 in the frame coordinate system S f are known, and are pre-calibrated and stored as inherent parameters of the integrated multi-order measurement calibration frame 1. The corresponding coordinate vectors are denoted as p f,1 , p f,2 , and p f,3 , respectively.

[0041] This process obtains two sets of one-to-one corresponding three-dimensional point sets, and the process of solving the initial rotation matrix R0 and the initial translation vector T0 is converted into an absolute orientation problem of solving rigid body transformation parameters. In this embodiment, the singular value decomposition method is used for solving. First, the centroids of the two sets of point sets are calculated respectively: wherein: is the centroid coordinate vector of the three prism points 2 in the global coordinate system S g ; is the summation symbol, indicating that the summation is performed for index i from 1 to 3; p g,i is the coordinate vector of the i-th prism point 2 in the global coordinate system S g .

[0042] wherein: is the centroid coordinate vector of the three prism points 2 in the frame coordinate system S f ; is the summation symbol, indicating the summation over the index i from 1 to 3; pi f,i is the coordinate vector of the i-th prism point 2 in the frame coordinate system S f .

[0043] Then, a covariance matrix H is constructed from the de-centroidized coordinates: wherein: H is a 3x3 covariance matrix; is the summation symbol, indicating the summation over the index i from 1 to 3; is the de-centroidized coordinate column vector of the i-th prism point 2 in the frame coordinate system S f ; is the transpose of the de-centroidized coordinate column vector of the i-th prism point 2 in the global coordinate system S g , i.e. a row vector.

[0044] The covariance matrix H is singular value decomposed: H = UΣV T ; wherein: U is an orthogonal 3x3 matrix; Σ is a diagonal 3x3 matrix with the singular values of the matrix H on the diagonal; V is an orthogonal 3x3 matrix; V T is the transpose matrix of the matrix V.

[0045] The initial rotation matrix R0 is calculated from: R0 = VU T ; wherein: R0 is the initial rotation matrix of the frame coordinate system S f relative to the global coordinate system S g , describing the initial pose of the integrated multi-order measurement calibration frame 1; V and U are the orthogonal matrices resulting from the singular value decomposition described above; U T is the transpose matrix of the matrix U.

[0046] After obtaining the initial rotation matrix R0, the initial translation vector T0 is calculated by the following equation: wherein: T0 is the initial translation vector of the frame coordinate system S f at the origin O f in the global coordinate system S g , i.e. the initial absolute coordinate vector of the integrated multi-order measurement calibration frame 1; is the centroid coordinate vector of the three prism points 2 in the global coordinate system S g ; R0 is the initial rotation matrix of the frame coordinate system S f relative to the global coordinate system S g , which describes the initial pose of the integrated multi-order measurement calibration frame 1; is the centroid coordinate vector of the three prism points 2 in the frame coordinate system S f ; • denotes the multiplication operation of a matrix and a vector.

[0047] After the initial rotation matrix R0 and the initial translation vector T0 are solved in step S2, step S3 is performed. The purpose of step S3 is to calibrate the internal pose perception system (i.e. the dual-axis tilt sensor 4) using the initial pose accurately obtained by external measurement, and determine the systematic reading offset inherent to the system caused by installation errors and other factors.

[0048] The initial rotation matrix R0 completely describes the initial absolute pose of the frame coordinate system S f relative to the global coordinate system S g . From the initial rotation matrix R0, the corresponding initial absolute pitch angle a0 and the initial absolute roll angle b0 can be inversely solved. Let the elements of the initial rotation matrix R0 be r kj0 , where k is the row index and j is the column index, then the initial pose angles are calculated by the following equations: wherein: a0 is the initial absolute pitch angle of the integrated multi-order measurement calibration frame 1; b0 is the initial absolute roll angle of the integrated multi-order measurement calibration frame 1; atan2(y, x) is the two-parameter inverse tangent function; arcsin(x) is the inverse sine function; are the elements of the initial rotation matrix R0 in the corresponding row and column, respectively.

[0049] Within the same static time window in which the external observation is performed in step S2, the output readings of the two-axis tilt sensor 4 are synchronously acquired to obtain the initial raw reading of the roll angle φ raw (0) and the initial raw reading of the pitch angle θ raw (0).

[0050] The calibration offset is defined as the difference between the initial attitude angle obtained by the external measurement and the initial raw reading of the two-axis tilt sensor 4. The calibration offset Offset α in the roll angle direction and the calibration offset Offset β in the pitch angle direction are determined respectively by the following equations: Offset α = a0- θ raw (0); wherein: Offset α is the calibration offset in the pitch angle direction; a0is the initial absolute pitch angle of the integrated multi-order measurement calibration frame 1; θ raw (0) is the initial raw reading of the pitch angle of the two-axis tilt sensor 4 at the initial time.

[0051] Offset β = b0- φ raw (0); wherein: Offset β is the calibration offset in the roll angle direction; b0is the initial absolute roll angle of the integrated multi-order measurement calibration frame 1; φ raw (0) is the initial raw reading of the roll angle of the two-axis tilt sensor 4 at the initial time.

[0052] The two calculated calibration offsets Offset α and Offset β are fixed constants, which will be stored and used for the correction of all subsequent real-time attitude data.

[0053] After completing the initial calibration stages S1 to S3, the method of this invention enters the real-time monitoring and calculation stage. This stage begins in step S4, which involves continuous dynamic data acquisition of the position of the target object 5 and the attitude of the integrated multi-stage measurement and calibration frame 1 during construction processes such as drilling or lowering the rebar cage. In this embodiment, the target object 5 is a key vertical component in the construction process, which typically has a regular circular cross-section. Specifically, in the drilling stage, the target object 5 is the drill rod of the drilling rig; in the rebar cage lowering stage, the target object 5 is the rebar cage to be lowered. By continuously locating the center of these target objects 5, real-time tracking of the actual pile core position is achieved.

[0054] In step S4, the measurement system within the integrated multi-stage measurement and calibration framework 1 is activated. The internal relative measurement system and the internal attitude sensing system synchronously acquire data at a preset high sampling frequency (e.g., 50Hz). At any sampling time t, the three laser rangefinders 3 in the internal relative measurement system measure and output the real-time distance from their respective mounting points to the surface of the target object 5. and

[0055] At the same sampling time t, the dual-axis tilt sensor 4 in the internal attitude sensing system synchronously measures and outputs the raw roll angle reading φ of the integrated multi-stage measurement and calibration frame 1. raw (t) and the original reading of the pitch angle θ raw (t). These raw readings directly reflect the real-time attitude changes of the integrated multi-stage measurement calibration frame 1 caused by construction disturbances such as ground vibration and uneven settlement.

[0056] Real-time distance data collected and This is used to calculate the three-dimensional relative position vector of the center of target object 5 using the three-point circle method. First, based on the three laser rangefinders 3 in the frame coordinate system S... f The known self-coordinates (x) s,h ,y s,h ,z s,h ) and the known launch direction unit vector The three points where the laser beam intersects with the contour of target object 5 were calculated. In the frame coordinate system S f 3D coordinates in: in: Let be the real-time three-dimensional coordinate vector of the point measured by the h-th laser rangefinder 3 on the surface of the target object at time t. This coordinate is represented in the frame coordinate system. (x s,h ,y s,hz s,h ) is the three-dimensional coordinate vector of the fixed installation position of the h-th laser ranging sensor 3 in the frame coordinate system; d h (t) is the real-time distance measurement value output by the h-th laser ranging sensor 3 at time t; is the unit direction vector of the measurement axis of the h-th laser ranging sensor 3 in the frame coordinate system.

[0057] By applying the formula to the three laser ranging sensors 3 , respectively, the real-time spatial coordinates of the three different points on the target object profile can be obtained, providing basic data for subsequent three-point circle solving.

[0058] Next, based on the prior condition that the target object 5 is a vertical member with a circular cross-section, the center is three-dimensionally positioned in the frame coordinate system. It is assumed that the three spatial points are located on the same horizontal cross-section of the target object 5. First, the x-y plane coordinate components of the three spatial points are extracted, denoted as

[0059] Next, the three-point circle method is applied to solve the center coordinates (x c ,y c ) of the circle determined by the three points. According to the geometric properties of the circle, the distance from the center to the three points is equal, so we have: where: are the two-dimensional coordinates of the three known points that are not on the same straight line; (x c ,y c ) are the two-dimensional coordinates of the center point to be solved; (x h -x c ) 2 +(y h -y c ) 2 is the square of the distance between any point (x h ,y h ) on the circumference and the center (x c ,y c ), which is equal to the square of the radius of the circle.

[0060] By simultaneously solving these two equations about x c and y c , the coordinates of the center can be uniquely determined. The center coordinates are the x and y coordinate components of the center of the target object 5 in the frame coordinate system.

[0061] To obtain the complete three-dimensional relative position, the z-coordinate components of the three measurement points are averaged to obtain the z-coordinate component of the center of the target object 5. c ,Right now

[0062] Ultimately, these three coordinate components together constitute the center of target object 5 in the frame coordinate system S. f The three-dimensional relative position vector The specific form of the three-dimensional relative position vector is as follows: in: x is the three-dimensional relative position vector of the center of target object 5 in the frame coordinate system of the integrated multi-order measurement and calibration frame 1; c (t) represents the time t when the center of target object 5 is relative to the frame coordinate system S. f Origin O f x-coordinate components; y c (t) represents the time t when the center of target object 5 is relative to the frame coordinate system S. f Origin O f y-axis coordinate components; z c (t) represents the center of object 5 relative to the frame coordinate system S. f Origin O f The z-axis coordinate component reflects the average height of the target object at the measurement section.

[0063] After acquiring the original relative position and attitude data in step S4, step S5 is executed. Step S5 is the core calculation part of the method of this invention. Its purpose is to perform attitude compensation calculation on the acquired original data. The relative position vector calculated based on the tilted frame coordinate system is transformed by coordinate rotation to obtain the center of the target object 5 in the global coordinate system S. g The precise relative displacement.

[0064] First, the raw reading of the dual-axis tilt sensor 4 at time t is corrected to calculate the real-time absolute attitude of the integrated multi-stage measurement calibration frame 1 at time t. The correction process utilizes the fixed calibration offset determined in step S3, which is achieved by adding the real-time raw reading to the calibration offset. The specific calculation formula is as follows: α(t)=θ raw (t)+Offset α ; in: α(t) is the real-time absolute pitch angle of the integrated multi-order measurement and calibration framework 1 at time t; θ raw(t) is the original reading of the pitch angle of the dual-axis tilt sensor 4 at time t; Offset α is the calibration offset in the direction of the pitch angle.

[0065] β(t) = φ raw (t) + Offset β ; wherein: β(t) is the real-time absolute roll angle of the integrated multi-order measurement calibration frame 1 at time t; φ raw (t) is the original reading of the roll angle of the dual-axis tilt sensor 4 at time t; Offset β is the calibration offset in the direction of the roll angle.

[0066] Next, according to the calculated real-time absolute attitude angles α(t) and β(t), a real-time rotation matrix R(t) for coordinate transformation is constructed. The real-time rotation matrix R(t) represents the attitude transformation relationship from the frame coordinate system S f to the global coordinate system S g . The real-time rotation matrix R(t) is composed of a rotation matrix R x (β(t)) representing the roll angle rotation around the x-axis and a rotation matrix R y (α(t)) representing the pitch angle rotation around the y-axis, that is, R(t) = R x (β(t))R y (α(t)).

[0067] Finally, using the constructed real-time rotation matrix R(t), the three-dimensional relative position vector obtained in step S4 is subjected to coordinate transformation to obtain a three-dimensional relative displacement vector ΔC g (t) in the global coordinate system. This transformation process is the attitude compensation operation, and its mathematical expression is: wherein: ΔC g (t) is the three-dimensional relative displacement vector, which is the spatial displacement of the center of the target object 5 relative to the origin of the integrated multi-order measurement calibration frame 1 in the global coordinate system; R(t) is the real-time rotation matrix constructed according to the real-time absolute attitude angles α(t) and β(t); is the three-dimensional relative position vector of the center of the target object 5 in the frame coordinate system of the integrated multi-order measurement calibration frame 1.

[0068] After completing the attitude compensation operation in step S5, the three-dimensional relative displacement vector ΔC g(t), the final absolute coordinates of the target 5 center in the global coordinate system S g at time t are calculated and outputted.

[0069] The final absolute coordinate vector P target (t) of the target 5 center at time t is obtained by vector sum of the absolute coordinate T0 of the integrated multi-order measurement calibration frame 1 at the initial calibration time and the real-time three-dimensional relative displacement vector ΔC g (t) of the target 5 center relative to the origin of the integrated multi-order measurement calibration frame 1, that is, P target (t) = T0 + ΔC g (t).

[0070] Since the pile foundation construction deviation mainly concerns the position deviation in the horizontal plane, only the final absolute horizontal coordinates (X target (t), Y target (t)) of the target 5 center are extracted and calculated. Expanding the above formula to the coordinate component form, the final absolute horizontal coordinates (X g (t), Y target (t)) of the target 5 center in the global coordinate system S target are calculated as follows: X target (t) = X0 + ΔC g,x (t); Y target (t) = Y0 + ΔC g,y (t); Wherein: X0 and Y0 are the X and Y axis coordinate components of the absolute coordinate T0 at the initial calibration time in the global coordinate system S g ; ΔC g,x (t) and ΔC g,y (t) are the X and Y axis coordinate components of the three-dimensional relative displacement vector ΔC g (t) in the global coordinate system S g .

[0071] To obtain the pile center deviation value, the calculated final absolute horizontal coordinates (X target (t), Y target (t)) of the target 5 are compared with the pre-set design pile center coordinates (X b , Y b ). The pile center deviation vector E(t) is calculated by the following formula: Wherein: E(t) is the two-dimensional real-time deviation vector at time t; (X target (t),Y target (t)) is the final absolute horizontal coordinate of the target 5 center in the global coordinate system S g at time t; (X b ,Y b ) is the pre-set design pile center coordinate of the pile center in the global coordinate system S g .

[0072] The components of the deviation vector E(t) are the final measurement results, such as X-direction deviation and Y-direction deviation. These values are output in real time to the display device for on-site personnel to monitor, or recorded to the data storage unit for subsequent quality acceptance.

[0073] In order to further improve the real-time feedback and safety of the construction process, the method further includes a deviation overrun alarm step. One or more allowable thresholds of pile center deviation are pre-set in the system software or data processing unit, such as the maximum allowable value of the plane comprehensive deviation. The specific value of the allowable threshold is set according to at least one selected from the group consisting of: the design pile diameter of the pile foundation to be measured; and the relevant building pile detection technical specification (such as the “Building Pile Detection Technical Specification JGJ106” of China). At each sampling time, the system compares the size of the calculated real-time deviation vector E(t) with the pre-set threshold in real time. Once the deviation size is detected to exceed the pre-set threshold, the system will immediately trigger an alarm signal automatically. The alarm signal can be specifically realized as the ringing of the on-site sound and light alarm, or the prominent color change or pop-up prompt on the monitoring software interface, so as to immediately remind the on-site construction management personnel to pay attention to the deviation and take necessary correction measures, thereby effectively avoiding the generation of out-of-tolerance piles.

Claims

1. A method for measuring the core deviation of a cast-in-place bored pile based on a three-point circle method, characterized in that, The method comprises the following steps: S1, providing and installing an integrated multi-order measurement calibration frame (1) on a steel casing at a pile position, wherein the integrated multi-order measurement calibration frame (1) is integrated with an external absolute reference system, an internal relative measurement system and an internal attitude perception system; S2, measuring the external absolute reference system to solve the initial attitude and the initial absolute coordinate of the integrated multi-order measurement calibration frame (1) in a global coordinate system; S3, calibrating the internal attitude perception system according to the initial attitude solved in the S2 step to determine a calibration offset; S4, in the construction process, obtaining the coordinates of three space points on the profile of a target object (5) through the internal relative measurement system, solving the three-dimensional relative position vector of the center of the target object (5) by the three-point circle method, and obtaining the real-time attitude of the integrated multi-order measurement calibration frame (1) through the internal attitude perception system; S5, performing attitude compensation operation on the three-dimensional relative position vector according to the real-time attitude obtained in the S4 step and the calibration offset determined in the S3 step to obtain a three-dimensional relative displacement vector; S6, superimposing the horizontal component of the three-dimensional relative displacement vector obtained in the S5 step and the horizontal component of the initial absolute coordinate solved in the S2 step to obtain the final absolute horizontal coordinate of the center of the target object (5), and comparing it with the designed pile center coordinate to determine the pile center deviation.

2. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 1, characterized in that, The external absolute reference system comprises three prism points (2) fixedly connected to the top of the integrated multi-order measurement calibration frame (1).

3. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 2, characterized in that, In the S2 step, the measurement of the external absolute reference system refers to the measurement of the three-dimensional coordinates of the three prism points (2) in the global coordinate system by a total station.

4. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 1, characterized in that, In the S1 step, the internal relative measurement system comprises three laser ranging sensors (3) in a non-collinear layout, which are fixedly connected to the inner side wall of the integrated multi-order measurement calibration frame (1).

5. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 1, characterized in that, In the S1 step, the internal attitude perception system comprises a dual-axis tilt sensor (4) fixedly connected to the inner side wall of the integrated multi-order measurement calibration frame (1).

6. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 1, characterized in that, In the S2 step, the initial attitude comprises the initial pitch angle and the initial roll angle of the integrated multi-order measurement calibration frame (1).

7. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 1, characterized in that, The S5 step specifically comprises: calculating the corrected real-time absolute attitude by using the real-time attitude obtained in the S4 step and the calibration offset determined in the S3 step; and constructing a real-time rotation matrix according to the corrected real-time absolute attitude, and performing coordinate transformation on the three-dimensional relative position vector by using the real-time rotation matrix to obtain the three-dimensional relative displacement vector. In the S4 step, the target object (5) is selected from one of a drill pipe and a reinforcement cage having a circular cross section.

8. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 1, characterized in that, The method further comprises the following steps:

9. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 1, characterized in that, comparing the size of the pile center deviation with a preset threshold value, and triggering an alarm signal when the size of the pile center deviation exceeds the preset threshold value. ​ 10. The method for measuring the pile center deviation of cast-in-place bored pile based on three-point circle method according to claim 9, characterized in that, The preset threshold is set according to at least one selected from a group of a design pile diameter of the pile foundation to be detected and a related building foundation pile detection technical specification. The preset threshold is set according to at least one selected from a group of a design pile diameter of the pile foundation to be detected and a related building foundation pile detection technical specification.

Images