A method for monitoring uneven settlement based on distributed strain measurement

Abstract

The application discloses a non-uniform settlement monitoring method based on distributed strain measurement, and engineering structures are regarded as foundation beams, the foundation beams are divided into n units, the load distribution in each unit is regarded as unit uniform load, and is recorded as q i , i∈n; strain distributions ε1-ε n of the n units are obtained; load inversion coefficients k ji of the n units are obtained; unit uniform loads q1-q ji of the n units are calculated according to the load inversion coefficients k n of the n units and the strain ε1-ε n of the n units; settlement inversion coefficients n ji of the n units are obtained; and settlement distributions y1-y n of the n units are calculated according to the settlement inversion coefficients n ji of the n units and the unit uniform loads q1-q n of the n units. The application has high measurement precision, low long-term monitoring cost and is convenient to use, and is a new non-uniform settlement monitoring method.

Description

Technical Field

[0001] This invention relates to a method for monitoring uneven settlement based on distributed strain measurement, belonging to the field of engineering testing and monitoring technology. Background Technology

[0002] Uneven settlement is a significant component of structural deformation in foundations, tunnels, pipelines, and other structures, and is a crucial indicator of their overall performance. Uneven settlement can cause leaks, segment detachment from the track bed, and segment cracking in tunnels and other structures, posing serious threats to structural safety and operation. Railways are particularly sensitive to foundation settlement, as uneven settlement affects the stress deformation and service life of the track structure. Uneven settlement in highway or airport foundations can lead to slab separation or the formation of transverse or longitudinal cracks on the surface, severely reducing their service life. Therefore, monitoring uneven settlement in these structures is of paramount importance.

[0003] Currently, there are numerous methods for monitoring uneven settlement, with leveling being a relatively traditional approach. Leveling offers high accuracy, uses relatively inexpensive equipment, and is simple to operate. However, it relies heavily on manual labor, resulting in low efficiency and automation, and the monitoring distance is limited each time. Static leveling monitors tunnel settlement deformation based on the principle of communicating vessels. Static levels offer high accuracy, typically reaching 0.1 mm; and by adjusting the distribution of measuring points, automated monitoring within a certain range can be achieved. Installation is simple and implementation is convenient. However, static leveling also has some drawbacks, such as the tendency for liquid in the pipe to evaporate, making long-term monitoring difficult; and significant pressure loss in the pipe as the monitoring distance increases, limiting the monitoring range. Inclination measurement technology is an indirect monitoring method that measures the inclination angle of the tunnel cross-section using sensors and then calculates settlement from the inclination angle. Inclination measurement can achieve automated settlement monitoring with high accuracy. However, calculating settlement from the inclination angle generally requires complex fitting algorithms, making the calculation inconvenient.

[0004] Therefore, those skilled in the art urgently need to propose improved methods for monitoring uneven settlement to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] Objective: To overcome the shortcomings of existing technologies, this invention provides a method for monitoring uneven settlement based on distributed strain measurement. By installing distributed fiber optic sensors in foundations, tunnels, pipelines, etc., strain distribution is measured, and a strain-settlement inversion method is established to achieve distributed monitoring of uneven settlement in foundations, tunnels, pipelines, etc.

[0006] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for monitoring non-uniform settlement based on distributed strain measurement includes the following steps:

[0008] Step 1: Treat the engineering structure as a foundation beam, divide the foundation beam into n elements, and treat the load distribution within each element as a uniformly distributed load, denoted as q. i , i∈n.

[0009] Step 2: Obtain the strain distribution ε1~ε of n elements. n .

[0010] Step 3: Obtain the load inversion coefficients k for n elements. ji Based on the load inversion coefficients k of n elements ji and the strain ε1~ε of n elements n Calculate the uniformly distributed load q1~q for n elements. n Step 4: Obtain the settlement inversion coefficients n for n units. ji Based on the settlement inversion coefficients n of the n units ji And n uniformly distributed loads q1~q n Calculate the settlement distribution y1~y2 of n units. n .

[0011] As a preferred embodiment, the method further includes: Step 5: Based on the settlement distribution y1~y of the n units... n Obtain the uneven settlement curves of the engineering structures and perform threshold assessment analysis.

[0012] As a preferred embodiment, the engineering structure includes at least: tunnels, pipelines, plastic pipes, or steel pipes.

[0013] As a preferred embodiment, the strain distribution ε1~ε of the n units n The method for obtaining it includes the following steps:

[0014] Distributed fiber optic sensors are installed on each unit of the engineering structure.

[0015] The distributed strain on the fiber optic sensor under external load is extracted using a static analyzer, and the strain data is processed to obtain the strain distribution ε1~ε corresponding to the divided element. n .

[0016] As a preferred option, when monitoring foundation settlement, distributed fiber optic sensors are installed inside plastic or steel pipes; when monitoring underground structures such as tunnels and pipelines, distributed fiber optic sensors are installed on the upper and lower surfaces of the inner walls of the tunnels and pipelines.

[0017] As a preferred option, the load inversion coefficients k for n elements ji The calculation formula is as follows:

[0018] k ji =ε(|ij|d)

[0019] Where, k ji Let d represent the load inversion coefficient of the uniformly distributed load of the i-th element with respect to the j-th element, where i,j∈n, and d represents the uniformly distributed load q of the element. i Scope of application.

[0020] Where ε(|ij|d) represents the strain result of ε(x) at x=|ij|d, and ε(x) is calculated by the following formula:

[0021]

[0022] in, h is the height of the foundation beam (EI). eq is the equivalent bending stiffness in the longitudinal direction of the foundation beam, x is the distance from the unit concentrated load to the center of the element for which the settlement is calculated, and k is the subgrade coefficient.

[0023] As a preferred option, the uniformly distributed loads q1~q of the n elements are... n The calculation formula is as follows:

[0024]

[0025] in, Using the load inversion coefficients k of n elements ji Obtain.

[0026] As a preferred option, the settlement inversion coefficients n for n units ji The calculation formula is as follows:

[0027] n ji =y(|ij|d)

[0028] Where, n ji Let d represent the settlement inversion coefficient of the i-th element with respect to the j-th element under the uniformly distributed load, i,j∈n, and d represent the uniformly distributed load q of the element. i Scope of application.

[0029] Where y(|ij|d) represents the settlement result of y(x) at x=|ij|d, and y(x) is calculated by the following formula:

[0030]

[0031] in, K = kD, where k is the subgrade coefficient and D is the equivalent width of the foundation beam (EI). eq It is the equivalent bending stiffness in the longitudinal direction of the foundation beam, and x is the distance from the unit concentrated load to the center of the element for which the settlement is calculated.

[0032] As a preferred option, the settlement distribution of the n units is y1~y n The calculation formula is as follows:

[0033]

[0034] in, Settlement inversion coefficients n from n units ji Obtain.

[0035] Beneficial Effects: The non-uniform settlement monitoring method based on distributed strain measurement provided by this invention achieves the following beneficial effects compared with existing technologies:

[0036] 1. This invention utilizes distributed strain measurement to monitor uneven settlement of foundations, tunnels, pipelines, etc., which significantly reduces the impact on traffic volume and improves the convenience and safety of monitoring.

[0037] 2. This invention has high measurement accuracy, low long-term monitoring cost, and is easy to use. It is a new method for monitoring uneven settlement, providing a scientific basis for implementing scientific monitoring, scientific assessment, and scientific management, and has significant social and economic benefits. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the foundation beam unit division provided in an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of the fiber optic sensor deployment provided in an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of the strain inversion settlement process provided in an embodiment of the present invention.

[0041] Figure 4 This is a schematic diagram of a tunnel finite element model provided in an embodiment of the present invention.

[0042] Figure 5 This is a schematic diagram of the non-uniform settlement calculation results provided by the finite element model in the embodiment of the present invention.

[0043] Figure 6 This is a schematic diagram of the experimental model provided in an embodiment of the present invention.

[0044] Figure 7 This is a schematic diagram of the measured strain of the test model provided in the embodiment of the present invention.

[0045] Figure 8 This is a schematic diagram of the non-uniform settlement calculation results of the test model provided in the embodiment of the present invention. Detailed Implementation

[0046] The present invention will be further described below with reference to specific embodiments.

[0047] A method for monitoring uneven settlement based on distributed strain measurement is proposed. When directly monitoring foundation settlement, distributed fiber optic sensors are deployed on the surface of plastic or steel pipes; when monitoring underground structures such as tunnels and pipelines, distributed fiber optic sensors are installed on the surface of the tunnels and pipelines. Uneven settlement of the foundation causes deformation of the aforementioned plastic / steel pipes, tunnels, and pipelines, and this deformation is consistent with the settlement of the surrounding foundation. Therefore, this invention monitors uneven foundation settlement by measuring the strain distribution of the aforementioned plastic / steel pipes, tunnels, and pipelines and then calculating their vertical deformation. To calculate the settlement distribution from the strain distribution, the classic Winkler elastic foundation beam model is adopted, treating the aforementioned plastic / steel pipes, tunnels, and pipelines as elastic foundation beams. In the calculation theory of existing models, strain and deformation are calculated through load. Therefore, this invention proposes a strain-settlement inversion method, that is, firstly, the load distribution is analyzed using the measured strain distribution, and then the analyzed load is substituted into the deformation calculation formula to calculate the settlement distribution. When implementing distributed strain measurement, a long gauge length strain sensor is used. Therefore, when establishing the strain-settlement inversion model, the foundation beam is divided into n elements, with the element length consistent with the sensor's monitoring gauge length. Within each element, the load distribution can be simplified to a uniform distribution, with the uniformly distributed load on the i-th element being q. i .

[0048] (1) According to the theory of elastic foundation beams, the settlement distribution y and strain distribution ε of each element of the foundation beam under a unit concentrated load can be calculated as follows:

[0049]

[0050] Wherein, parameters K and β are calculated by the following formula:

[0051]

[0052] In the formula, K is the intensity of the subgrade coefficient in the direction of the equivalent width of the foundation beam; k is the subgrade coefficient; D is the equivalent width of the foundation beam; h is the height of the foundation beam; (EI) eq is the equivalent bending stiffness in the longitudinal direction of the foundation beam, and x is the distance from the unit concentrated load to the center of the calculation unit.

[0053] (2) Solve for the settlement distribution of each element of the foundation beam under a uniformly distributed unit load. and strain distribution as follows:

[0054] Unit load q i Under the action of concentrated load, the deformation of the tunnel structure can be obtained by integrating the concentrated load. Under a uniformly distributed load, the settlement deformation and strain deformation at the center of the calculation element are determined by... The effect of numerous concentrated loads on the center location of the calculation element is accumulated. That is:

[0055]

[0056] In the formula, y ix The unit load q at position i represents the average load per unit. i Settlement distribution at the center of the computational unit under the influence of ε; ix The unit load q at position i represents the average load per unit. i The strain distribution at the center of the calculation element under load is calculated. m This represents the distance from the concentrated load at position m on element i to the center of the calculation element.

[0057] Under concentrated load, both the settlement distribution y and the strain distribution ε are even functions. Therefore, the influence of a concentrated load at position m on element i on the center of the computational element is numerically equal to the influence of a concentrated load at the center of the computational element on position m on element i. That is:

[0058]

[0059] That is, the unit load q at position i. i This is transformed into countless concentrated loads acting at the center of the computational unit. Therefore, the unit uniform load q i Settlement distribution under action and strain distribution The result can be obtained by integrating the results under the concentrated load at the center of the calculation unit, that is:

[0060]

[0061] Discretize the continuous distribution results calculated above, and take the deformation corresponding to the middle position of each element as the representative value of the deformation of that element. Then, the settlement distribution of the unit uniformly distributed load of the i-th element under the action of the j-th element is obtained. and strain distribution for:

[0062]

[0063] (3) Solve for the uniformly distributed load q i Strain and settlement distribution of the foundation beam under load. Uniformly distributed load q distributed on the i-th element. i The strain ε of element j under action ij and sedimentation ij for:

[0064]

[0065] In the formula, d represents the uniformly distributed load q of the element. i Scope of application; y ij q i Settlement of element j under action; ε ij q i Strain at the sensor placement location of unit j under action.

[0066] (4) Solve for the uniformly distributed load q1~q n Strain and settlement distribution of the foundation beam under load:

[0067]

[0068] In the formula, y j This indicates the settlement of element j under load on all elements; ε j This represents the strain at the sensor placement location in element j under load on all elements. k ji n represents the load inversion coefficient of the uniformly distributed load of the i-th element with respect to the j-th element; ji This represents the settlement inversion coefficient of the i-th element with respect to the j-th element due to the uniformly distributed load.

[0069] (5) Assemble the strain equations of all monitoring units into a set of equations, with n equations and n unknowns (i.e., unit load q). i ~q n That is, to establish the load inversion calculation formula:

[0070]

[0071] Wherein, ε1~ε n The measured strain is from a distributed fiber optic sensor.

[0072] (6) The equations for uniformly distributed loads of all inversion elements are combined into a set of equations, n equations and n unknowns, thus establishing the settlement inversion calculation formula:

[0073]

[0074] Among them, y1~y n Uneven settlement of the entire tunnel, pipeline, or plastic / steel pipe.

[0075] Example 1:

[0076] Divide the data into monitoring and calculation units. For example... Figure 1As shown, when implementing distributed strain measurement, a long gauge length strain sensor is used. Therefore, when establishing the strain-settlement inversion model, the foundation beam is divided into n elements. Within each element, the load distribution can be simplified to a uniform distribution, and the uniformly distributed load on the i-th element is q. i The measured strain of the unit represents the uniform strain of the calculated unit. Distributed fiber optic sensors are installed. For example... Figure 2 As shown, when directly monitoring foundation settlement, distributed fiber optic sensors are deployed inside plastic or steel pipes; when monitoring underground structures such as tunnels and pipelines, distributed fiber optic sensors are installed on the upper and lower surfaces of the inner walls of the tunnels and pipelines.

[0077] Strain distribution is acquired and strain data is processed. Distributed strain on the fiber optic sensor under external load is extracted using a static analyzer, and the strain data is processed to obtain the strain ε1~ε1 corresponding to the divided element. n .

[0078] Calculate the strain and settlement distribution under uniformly distributed load, and generate the settlement calculation matrix:

[0079] (1) The settlement distribution y and strain distribution ε of each element of the foundation beam under a unit concentrated load are as follows:

[0080]

[0081] Wherein, parameters K and β are calculated by the following formula:

[0082]

[0083] In the formula, K is the intensity of the subgrade coefficient in the direction of the equivalent width of the foundation beam; D is the equivalent width of the foundation beam; h is the height of the foundation beam; (EI) eq is the equivalent bending stiffness in the longitudinal direction of the foundation beam, and x is the distance from the unit concentrated load to the center of the calculation unit.

[0084] (2) Solve for the settlement distribution of each element of the foundation beam under a uniformly distributed unit load. and strain distribution as follows:

[0085] Unit load q i Under the action of concentrated load, the deformation of the tunnel structure can be obtained by integrating the concentrated load. Under a uniformly distributed unit load, the settlement deformation and strain deformation at the center of the calculation element are determined by... The effect of numerous concentrated loads on the center location of the calculation element is accumulated. That is:

[0086]

[0087] In the formula, yix The unit load q at position i represents the average load per unit. i Settlement distribution at the center of the computational unit under the influence of ε; ix The unit load q at position i represents the average load per unit. i The strain distribution at the center of the calculation element under load is calculated. m This represents the distance from the concentrated load at position m on element i to the center of the calculation element.

[0088] Under concentrated load, both the settlement distribution y and the strain distribution ε are even functions. Therefore, the influence of a concentrated load at position m on element i on the center of the computational element is numerically equal to the influence of a concentrated load at the center of the computational element on position m on element i. That is:

[0089]

[0090] That is, the unit load q at position i. i This is transformed into countless concentrated loads acting at the center of the computational unit. Therefore, the unit uniform load q i Settlement distribution under action and strain distribution The result can be obtained by integrating the results under the concentrated load at the center of the calculation unit, that is:

[0091]

[0092] Discretize the continuous distribution results calculated above, and take the deformation corresponding to the middle position of each element as the representative value of the deformation of that element. Then, the settlement distribution of the unit uniformly distributed load of the i-th element under the action of the j-th element is obtained. and strain distribution for:

[0093]

[0094] (3) Solve for the uniformly distributed load q i Strain and settlement distribution of the foundation beam under uniformly distributed load q. i The strain ε of element j under the action of (distributed on the i-th element) ij and sedimentation ij for:

[0095]

[0096] In the formula, d represents the uniformly distributed load q of the element. i Scope of application; y ij q i Settlement of element j under action; ε ij q i Strain at the sensor placement location of unit j under action.

[0097] (4) Solve for the uniformly distributed load q1~q n Strain and settlement distribution of the foundation beam under load:

[0098]

[0099] In the formula, y j This indicates the settlement of element j under load on all elements; ε j This represents the strain at the sensor placement location in element j under load on all elements. k ji n represents the load inversion coefficient of the uniformly distributed load of the i-th element with respect to the j-th element; ji This represents the settlement inversion coefficient of the i-th element with respect to the j-th element due to the uniformly distributed load.

[0100] (5) Assemble the strain equations of all monitoring units into a set of equations, with n equations and n unknowns (i.e., unit load q). i ~q n That is, to establish the load inversion calculation formula: Wherein, ε1~ε n The measured strain is from a distributed fiber optic sensor.

[0101] (6) The equations for uniformly distributed loads of all inversion elements are combined into a set of equations, n equations and n unknowns, thus establishing the settlement inversion calculation formula:

[0102]

[0103] Among them, y1~y n This involves calculating the uneven settlement of the entire tunnel, pipeline, or plastic / steel pipe. Input the strain distribution and invert the load distribution. First, solve for the load inversion coefficients k of n uniformly distributed loads on n elements. ji Then, monitor the strain ε1 to ε of all monitoring units. n Substitute these values ​​into the load inversion calculation formula to solve for the load distribution q1~q on the tunnel, pipeline, or plastic / steel pipe. n Input the load distribution and calculate the settlement distribution. First, solve for the settlement inversion coefficients n of n uniformly distributed loads on n elements. ji Then, the loads q1 to q2 retrieved from all monitoring units are... n By substituting the values ​​into the settlement inversion calculation formula, the settlement distribution y1~y2 of the entire tunnel, pipeline, or plastic / steel pipe can be solved. n Based on the above analysis, the calculation process of the non-uniform settlement monitoring method for distributed strain of the present invention is as follows: Figure 3 As shown, the specific process includes the following:

[0104] The first step is to divide the monitoring and calculation units. The entire tunnel, pipeline, or plastic / steel pipe is divided into n units, and n uniformly distributed loads are applied to them. The magnitude of the uniformly distributed loads can be 0. The strain of the measured unit represents the uniform strain of the calculation unit.

[0105] The second step is to install distributed fiber optic sensors. When monitoring foundation settlement, the distributed fiber optic sensors are deployed inside plastic or steel pipes; when monitoring underground structures such as tunnels and pipelines, the distributed fiber optic sensors are installed on the upper and lower surfaces of the inner walls of the tunnels and pipelines.

[0106] The third step is to collect strain distribution data and process it. Distributed strain on the fiber optic sensor under external load is extracted using a static analyzer, and the strain data is processed to obtain the strain ε1~ε1 corresponding to the divided element. n .

[0107] The fourth step is to solve for the load inversion coefficient k. ij Settlement inversion coefficient n ij First, calculate the strain and deformation under a unit concentrated load. The settlement distribution y and strain distribution ε of each element of the foundation beam under a unit concentrated load are as follows:

[0108]

[0109] Wherein, parameters K and β are calculated by the following formula:

[0110]

[0111] In the formula, K is the intensity of the subgrade coefficient in the direction of the equivalent width of the foundation beam; D is the equivalent width of the foundation beam; h is the height of the foundation beam; (EI) eq It is the equivalent bending stiffness in the longitudinal direction of the foundation beam, and x is the distance from the unit concentrated load to the center of the element for which the settlement is calculated.

[0112] Then, using the formula below, solve for the load inversion coefficient k of n uniformly distributed loads on n elements. ij and settlement inversion coefficient n ij :

[0113] k ji =ε(|ij|d)

[0114] n ji =y(|ij|d)

[0115] In the formula, k ji n represents the load inversion coefficient of the uniformly distributed load of the i-th element with respect to the j-th element. jiε(|ij|d) represents the load inversion coefficient of the uniformly distributed load of the i-th element to the j-th element; ε(|ij|d) represents the strain result of ε(x) at x=|ij|d, that is, the strain at the sensor placement position of the j-th element when a unit uniformly distributed load is applied to the i-th element; y(|ij|d) represents the settlement result of y(x) at x=|ij|d, that is, the settlement of the j-th element when a unit uniformly distributed load is applied to the i-th element.

[0116] Step 5: Input strain and invert load distribution. Input the strain ε1 to ε2 of all monitored units. n and load inversion coefficient k ji Substitute these values ​​into the load inversion calculation formula to solve for the load distribution q1~q on the tunnel, pipeline, or plastic / steel pipe. n .

[0117]

[0118] Step 6: Input the load distribution and calculate the settlement distribution. Invert the loads q1 to q2 from all monitoring units. n and settlement inversion coefficient n ji By substituting the values ​​into the settlement inversion calculation formula, the settlement distribution y1~y2 of the entire tunnel, pipeline, or plastic / steel pipe can be solved. n .

[0119]

[0120] Step 7: Analyze the settlement distribution y1~y throughout the tunnel, pipeline, or plastic / steel pipe. n Plot the uneven settlement curve of the structure and perform threshold assessment analysis.

[0121] Example 2:

[0122] The accuracy of this method is verified below using finite element simulation examples:

[0123] Using the midas gts nx software to simulate a tunnel, such as Figure 4 As shown. The cross-section has an outer diameter of 6m and an inner diameter of 5.4m. The tunnel is 120m long. The beam is divided into 1.5m units, for a total of 80 units. The interaction between the tunnel and the soil is simulated using spring elements. A vertical spring element with a length of 10cm is placed at each node of the model. A uniformly distributed load of 1000kN / m is applied within a 1.5m range at the mid-span of the elastic foundation beam. The measured strain data are then substituted into the formula to calculate the corresponding tunnel settlement, and the results are as follows. Figure 5 As shown, from Figure 7As can be seen from the results, the measured values ​​and calculated values ​​are basically consistent when using the method presented in this paper for inversion. The calculated settlement is highly accurate in the middle region of the settlement trough, and its value is slightly smaller than the actual settlement value. The maximum relative error is about -1.2%, which is relatively high.

[0124] Example 3:

[0125] like Figure 6 As shown, the elastic foundation beam model uses PVC plastic pipes to simulate the main structure of the tunnel. The middle 1.8m section of the model is divided into 9 units, each 20cm in length. A long-gauge FBG sensor is installed at the bottom axis of each unit, and the FBG sensors are connected in series. The gauge length of the FBG sensor is 15cm. The model box used in the experiment is made of sheet metal with a thickness of about 1.5mm, and the overall dimensions of the model box are about 360cm × 40cm × 40cm. The entire PVC plastic pipe is buried in sand.

[0126] like Figure 7 As shown, the strain measured in the experiment is... Figure 7 The strain distribution is substituted into the formula to invert the settlement of the tunnel model, and the results are as follows: Figure 8 As shown in the figure, the calculated and measured settlements in the middle area of ​​the settlement trough, specifically in units B4, B5, and B6, show a high degree of agreement. Unit B5 exhibits the largest settlement, with a calculation error of less than 0.2 mm and a relative error not exceeding 9%. Based on this, the method is sufficient to meet the practical needs of engineering monitoring.

[0127] The distributed strain sensing technology employed in this invention is a recently developed high-tech field. It boasts numerous advantages, including distributed measurement, large monitoring range, corrosion resistance, and high accuracy. Furthermore, its large-scale deployment is cost-effective, making it highly suitable for monitoring "long-line facilities" such as foundations, tunnels, and pipelines. Uneven settlement leads to strain distribution in foundations and tunnels, and there is a direct correlation between the two. Therefore, uneven settlement can be monitored through strain distribution monitoring.

[0128] This invention proposes to introduce distributed optical fiber sensing technology to measure the strain distribution caused by uneven settlement, establish a strain-settlement inversion method, and realize uneven settlement monitoring. This method can achieve automated monitoring, has low cost, and shows good prospects.

[0129] 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 monitoring non-uniform settlement based on distributed strain measurement, characterized in that: Includes the following steps: Step 1: Treat the engineering structure as a foundation beam, divide the foundation beam into n elements, and treat the load distribution within each element as a uniformly distributed load, denoted as q. i , ; Step 2: Obtain the strain distribution of n elements ; Step 3: Obtain the load inversion coefficients of n elements Based on the load inversion coefficients of n elements and strain of n units Calculate the uniformly distributed load of n elements. ~ ; Step 4: Obtain the settlement inversion coefficients of n units Based on the settlement inversion coefficients of n units and uniformly distributed loads on n elements ~ Calculate the settlement distribution of n units. ; Load inversion coefficients for n elements The calculation formula is as follows: ； in, This represents the load inversion coefficient of the uniformly distributed load of the i-th element with respect to the load of the j-th element. , Indicates uniformly distributed load on the element Scope of application; in, express exist The strain results Calculated using the following formula: ； in, h is the height of the foundation beam (EI). eq is the equivalent bending stiffness in the longitudinal direction of the foundation beam, x is the distance from the unit concentrated load to the center of the element for which the settlement is calculated, and k is the subgrade coefficient; Uniformly distributed load on n elements ~ The calculation formula is as follows: ； in, Load inversion coefficients of n elements Obtain; Settlement inversion coefficients of n units The calculation formula is as follows: ； in, This represents the settlement inversion coefficient of the i-th element with respect to the j-th element under the uniformly distributed load. , Indicates uniformly distributed load on the element Scope of application; in, express exist The settlement results Calculated using the following formula: ； in, , k is the subgrade coefficient, D is the equivalent width of the foundation beam, (EI) eq It is the equivalent bending stiffness in the longitudinal direction of the foundation beam, and x is the distance from the unit concentrated load to the center of the element whose settlement is being calculated. Settlement distribution of n units The calculation formula is as follows: ； in, Settlement inversion coefficients from n units Obtain.

2. The non-uniform settlement monitoring method based on distributed strain measurement according to claim 1, characterized in that: Also includes: Step 5: Based on the settlement distribution of n units Obtain the uneven settlement curves of the engineering structures and perform threshold assessment analysis.

3. A method for monitoring non-uniform settlement based on distributed strain measurement according to claim 1 or 2, characterized in that: The engineering structures include at least: tunnels, pipelines, plastic pipes or steel pipes.

4. A method for monitoring non-uniform settlement based on distributed strain measurement according to claim 1 or 2, characterized in that: Strain distribution of the n units The method for obtaining it includes the following steps: Install distributed fiber optic sensors on each unit of the engineering structure; The distributed strain on the fiber optic sensor under external load is extracted using a static analyzer, and the strain data is processed to obtain the strain distribution corresponding to the divided unit. .

5. The non-uniform settlement monitoring method based on distributed strain measurement according to claim 4, characterized in that: When monitoring foundation settlement, distributed fiber optic sensors are installed inside plastic or steel pipes; when monitoring tunnels, pipelines, and underground structures, distributed fiber optic sensors are installed on the upper and lower surfaces of the inner walls of the tunnels and pipelines.

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