A pile foundation positioning and quantitative damage identification method and device and a storage medium

Abstract

The application discloses a pile foundation positioning and quantitative damage identification method and device and a storage medium, and belongs to the technical field of engineering detection. The method comprises the following steps: dividing a pile body into a plurality of pile body sections, and acquiring acceleration time history data of nodes at both ends of each pile body section; performing modal analysis on the acceleration time history data, and estimating modal shapes of each node; calculating modal strain energy residual variables of each pile body section by using the modal shapes; drawing a curve of the modal strain energy residual variables of each pile body section according to the division order, and positioning a pile body section corresponding to a protruding position of the curve as a damage section; establishing a numerical relationship between the modal strain energy residual variables and the pile body integrity, and converting the modal strain energy residual variables of the damage section into the pile body integrity based on the numerical relationship to quantitatively judge the damage degree. The application has the advantages of small amount of measured data and calculated amount, high identification precision, and convenient application in actual engineering.

Description

Technical Field

[0001] This invention relates to a method, device, and storage medium for pile foundation positioning and quantitative damage identification, belonging to the field of engineering testing technology. Background Technology

[0002] In recent years, dynamic fingerprint damage identification methods have been widely applied to the safety monitoring of pile foundations. Dynamic fingerprints include indicators such as mode shapes, curvature modes, flexibility matrix, stiffness matrix, strain modes, and modal strain energy, which can effectively locate damage in the structure. Existing quantitative analysis methods based on dynamic fingerprints include model correction, surrogate models, and sensitivity analysis. These methods require large amounts of data and computation, and their identification accuracy cannot be guaranteed, making them difficult to apply in practical engineering. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method, device and storage medium for pile foundation positioning and quantitative damage identification, which requires less data measurement and calculation, and has high identification accuracy, making it convenient to be applied to actual engineering.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention provides a method for pile foundation location and quantitative damage identification, comprising the following steps:

[0006] The pile body is divided into several pile segments, and the acceleration time history data of the nodes at both ends of each pile segment are obtained;

[0007] Modal analysis was performed on the acceleration time history data to estimate the mode shapes at each node;

[0008] The modal strain energy residual variables of each pile segment are calculated using modal vibration modes;

[0009] The modal strain energy residual variables of each pile segment are plotted as curves according to the division order, and the pile segment corresponding to the protrusion position of the curve is located as the damaged segment.

[0010] A numerical relationship is established between the residual variable of modal strain energy and the integrity of the pile body. Based on the numerical relationship, the residual variable of modal strain energy corresponding to the damaged section is converted into the integrity of the pile body to quantitatively determine the degree of damage.

[0011] The pile body is divided into 1 to N segments, and the nodes are divided into 1 to N+1. Adjacent pile body segments share a node.

[0012] Modal analysis of the acceleration time history data is performed to estimate the mode shapes of each node using the frequency response function method, random subspace method, frequency domain decomposition method, or Bayesian method.

[0013] The calculation of the residual modal strain energy of the pile segment using the modal vibration modes of each node includes: calculating the change in modal strain energy of the element before and after damage.

[0014]

[0015] in Let be the matrix representing the change in strain energy of the i-th modal before and after damage. and These are the strain energy matrices of the i-th modal before and after damage, respectively. and The calculation method is as follows:

[0016]

[0017] in , These are the mode shape vectors before and after the i-th order damage, respectively. , These are the global stiffness matrix before damage and the global stiffness matrix after damage, respectively.

[0018] Then calculate the modal strain energy residual variable:

[0019]

[0020] in Let be the residual variable matrix of the strain energy of the i-th modality. This is the difference operator, which means to perform difference operations on the matrix within the parentheses along the j-direction, where j is the dimension of the pile segment.

[0021] The acceleration time history data of the nodes at both ends of each pile segment are collected by acceleration sensors installed at the nodes at both ends of each pile segment.

[0022] The integrity P of the pile body is defined as: .

[0023] The expression for the numerical relationship between the residual variable of modal strain energy and the integrity of the pile body is as follows:

[0024] .

[0025] in The coordinates of the measuring point are along the direction of the pile.

[0026] The partial derivative in the expression relating the residual variable of modal strain energy to the integrity of the pile can be calculated using the following formula:

[0027] { ∂ φ i ∂ P ∂ λ i ∂ P } = [ K − λ i M − M φ i φ i T M 0 ] − 1 { − ( ∂ K ∂ P − λ i ∂ M ∂ P ) φ i 1 2 φ i T ∂ M ∂ P φ i }

[0028]

[0029]

[0030] Where M is the global quality matrix. Let be the i-th eigenvalue.

[0031] Secondly, the present invention provides a pile foundation positioning and quantitative damage identification device, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to perform operations according to the instructions to execute the steps of the method.

[0032] Thirdly, the present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the steps of the pile foundation positioning and quantitative damage identification method.

[0033] The beneficial effects of this invention are as follows: This invention provides a method, device, and storage medium for pile foundation positioning and quantitative damage identification. It requires only a few sensors, involves a small amount of data measurement, and has a simple calculation process with minimal computational load. It enables convenient and rapid positioning and qualitative damage identification of the pile body, providing data support for structural damage detection and health assessment. Furthermore, results have verified that this method has high identification accuracy. This invention can be applied to pile foundation structures, has a wide range of applications, and can be implemented in conjunction with programming, resulting in automatic and efficient data processing. Attached Figure Description

[0034] Figure 1 This is a model diagram of the high-pile wharf pile foundation in this invention;

[0035] Figure 2 This is a diagram showing the arrangement of sensors for the pile foundation in this invention;

[0036] Figure 3 This is a diagram showing the pile body segments and node layout of the present invention;

[0037] Figure 4 This invention calculates the modal vibration patterns of the pile body under different working conditions.

[0038] Figure 5 This invention provides a diagram of modal strain energy participation variables under different working conditions.

[0039] Figure 6 This is a diagram showing the quantitative damage identification results calculated under different working conditions in this invention. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0041] Example 1

[0042] This invention discloses a method for pile foundation location and quantitative damage identification, comprising the following steps:

[0043] Step 1: Divide the pile body into several pile segments and obtain the acceleration time history data of the nodes at both ends of each pile segment.

[0044] Step 2: Perform modal analysis on the acceleration time history data to estimate the mode shapes of each node.

[0045] Step 3: Calculate the residual modal strain energy of each pile segment using modal vibration modes.

[0046] Step four: Plot the residual modal strain energy of each pile segment into curves according to the division order, and locate the pile segment corresponding to the protruding position of the curve as the damaged segment. This provides a pile damage location and identification method based on MSERV for the damage unit.

[0047] Step 5: Establish the numerical relationship between the residual modal strain energy and the pile integrity. Based on the numerical relationship, convert the residual modal strain energy of the damaged section into the pile integrity to quantitatively determine the degree of damage. This provides a quantitative pile damage identification method based on MSERV for the damaged unit.

[0048] This invention requires only a few sensors and a small amount of data to be measured. In addition, the entire calculation process is simple and computationally intensive, enabling convenient and quick location and qualitative damage identification of piles, providing data support for structural damage detection and health assessment. Furthermore, the results have verified that this method has high identification accuracy.

[0049] Example 2

[0050] From a structural dynamics perspective, damage is essentially a change in the stiffness matrix of a structure. In practical engineering, the damaged area is localized and small-scale relative to the overall structure. Therefore, using dynamic fingerprints such as modal strain energy (MSE) to reflect localized damage can more accurately identify and locate the damage. Variable transformation of MSE yields the modal strain energy residual variable (MSERV), further improving its sensitivity to damage. By establishing the numerical relationship between MSERV and pile damage, quantitative analysis of the damage can be achieved.

[0051] This invention provides a method for pile foundation location and quantitative damage identification based on modal strain energy residual variable (MSERV). The vibration mode extraction and modal strain energy calculation methods involved are existing technologies and will not be detailed here. The example in this embodiment is based on dynamic testing of a physical model of a high-pile wharf pile foundation. A diagram of the high-pile wharf pile foundation model is shown below. Figure 1On the second pile on the left side of the high-pile wharf, in unit 5 (each pile is a unit every 10 cm from top to bottom), damage of 5%, 10%, 20%, and 30% is set respectively, that is, the integrity of the pile section is 95%, 90%, 80%, and 70% respectively. The specific steps include:

[0052] Step 1: Arrange accelerometers at equal intervals along the pile body, dividing the pile body into several segments. Place accelerometers at the nodes at both ends of each segment to acquire the acceleration time history data for that node. The accelerometer arrangement is as follows: Figure 2 As shown, one acceleration sensor is installed at the same location in each unit. The pile segments and node arrangements are as follows. Figure 3 As shown in the figure. Then, the acceleration time history data of this node is obtained through the accelerometer.

[0053] Step two involves modal analysis of the acceleration time history data to estimate the mode shapes at each node. This embodiment uses the hammer test and random subspace technique to extract the mode shapes at each measuring point on the pile shaft, and then calculates the modal strain energy of each pile segment. The first-order mode shapes measured in this invention are as follows: Figure 4 As shown.

[0054] Step 3: Calculate the residual modal strain energy of each pile segment using modal vibration modes. The specific steps are as follows:

[0055] Step 1: Calculate the change in modal strain energy of the first-order element before and after damage. ):

[0056]

[0057] in This represents the change in strain energy in the first-order mode before and after damage. and These represent the first-order modal strain energies before and after damage.

[0058] Step 2, calculate the modal strain energy residual variable (MSERV):

[0059]

[0060] in The residual variable matrix of the first-order modal strain energy. This is the difference operator, which means to perform difference operations on the matrix within the parentheses along the j-direction, where j is the dimension of the pile segment.

[0061] Step four: Plot the residual modal strain energy (MSERV) of each pile segment into curves according to the previously divided order, and locate the pile segment corresponding to the protruding position of the curve as the damaged segment. Plot the relationship curve between MSERV and the pile segment as follows: Figure 5As shown, the measured data shows fluctuations in the MSERV curve due to the presence of noise. The MSERV curve of the damaged section is higher than that of other pile sections, and the damaged section is identified as pile section 5.

[0062] Step 5: Establish the numerical relationship between the residual modal strain energy and the pile integrity. Based on this numerical relationship, convert the residual modal strain energy of the damaged section into pile integrity to quantitatively determine the degree of damage, thereby achieving quantitative damage identification of the pile. This specifically includes the following steps:

[0063] Step 1: The integrity of a pile segment is described by the ratio of its stiffness after damage to its stiffness before damage, and is defined as the pile integrity index P.

[0064]

[0065] in For the integrity of the pile body, and These are the stiffness matrices of the pile segment before and after damage, respectively.

[0066] Step 2: By establishing the numerical relationship between pile integrity and modal strain energy residual variables, the expression for pile integrity is obtained:

[0067]

[0068] The partial derivatives in the above formula can be calculated using the following formula:

[0069] { ∂ φ i ∂ P ∂ λ i ∂ P } = [ K − λ i M − M φ i φ i T M 0 ] − 1 { − ( ∂ K ∂ P − λ i ∂ M ∂ P ) φ i 1 2 φ i T ∂ M ∂ P φ i }

[0070]

[0071]

[0072] Where K is the global stiffness matrix and M is the global mass matrix. Let be the i-th eigenvalue.

[0073] This yields the pile segment integrity described by the ratio of pile stiffness after damage to pile stiffness before damage, such as... Figure 6 As shown, this method can correctly identify the location of damage and the amount of damage described by stiffness in the pile segment. Furthermore, it can be seen that the quantitative damage identification error is within 10% for piles with 5% to 20% damage, and within 20% to 30% damage, indicating that the method of this invention has strong robustness.

[0074] Example 3

[0075] This embodiment discloses a pile foundation damage identification device, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method described in Embodiment 1 or 2.

[0076] Example 4

[0077] This embodiment describes a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the method described in Embodiment 1 or 2.

[0078] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0079] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0080] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0081] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0082] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for pile foundation location and quantitative damage identification, characterized in that: Includes the following steps: The pile body is divided into several pile segments, and the acceleration time history data of the nodes at both ends of each pile segment are obtained; Modal analysis was performed on the acceleration time history data to estimate the mode shapes at each node; The modal strain energy residual variables of each pile segment are calculated using modal vibration modes; The modal strain energy residual variables of each pile segment are plotted as curves according to the division order, and the pile segment corresponding to the protrusion position of the curve is located as the damaged segment. Establish the numerical relationship between the residual variable of modal strain energy and the integrity of the pile body. Based on the numerical relationship, convert the residual variable of modal strain energy corresponding to the damaged section into the integrity of the pile body to quantitatively determine the degree of damage. The residual modal strain energy of this pile segment is calculated using the modal vibration modes at each node, including: calculating the change in modal strain energy of the element before and after damage. ； in Let be the matrix representing the change in strain energy of the i-th modal before and after damage. and These are the strain energy matrices of the i-th modal before and after damage, respectively. and The calculation method is as follows: ； in , These are the mode shape vectors before and after the i-th order damage, respectively. , These are the global stiffness matrix before damage and the global stiffness matrix after damage, respectively. Then calculate the modal strain energy residual variable: ； in Let be the residual variable matrix of the strain energy of the i-th modality. This is the difference operator, which means to perform the difference operation on the matrix within the parentheses along the j-direction, where j is the dimension of the pile segment; The integrity P of the pile body is defined as: ; The expression for the numerical relationship between the residual variable of modal strain energy and the integrity of the pile body is as follows: ； in The coordinates of the measuring point are along the direction of the pile.

2. The pile foundation positioning and quantitative damage identification method according to claim 1, characterized in that: The pile body is divided into 1 to N segments, and the nodes are divided into 1 to N+1. Adjacent pile body segments share a node.

3. The pile foundation positioning and quantitative damage identification method according to claim 1, characterized in that: Modal analysis of the acceleration time history data is performed to estimate the mode shapes of each node using the frequency response function method, random subspace method, frequency domain decomposition method, or Bayesian method.

4. The pile foundation positioning and quantitative damage identification method according to claim 1, characterized in that: The acceleration time history data of the nodes at both ends of each pile segment are collected by acceleration sensors installed at the nodes at both ends of each pile segment.

5. The pile foundation positioning and quantitative damage identification method according to claim 1, characterized in that: The partial derivative in the expression relating the residual variable of modal strain energy to the integrity of the pile can be calculated using the following formula: ； ； ； Where M is the global quality matrix. Let be the i-th eigenvalue.

6. A pile foundation positioning and quantitative damage identification device, characterized in that: It includes a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to perform the steps of the method according to any one of claims 1 to 5.

7. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that: When the computer program / instruction is executed by the processor, it implements the steps of the pile foundation positioning and quantitative damage identification method according to any one of claims 1-5.

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