Strain field reconstruction test device, system and method of arch dam structure

Abstract

The invention discloses a strain field reconstruction test device of an arch dam structure, which comprises an arch dam physical model, a temperature compensation gypsum block, an optical fiber and an optical fiber demodulator, a first end of the optical fiber is connected with the optical fiber demodulator, a second end of the optical fiber is not connected with other equipment, and a plurality of arch dam physical model strain gauges are arranged on the upper surface of the arch dam physical model. The arrangement path of strain gauges of the arch dam physical model is consistent with the arrangement path of the first section of optical fiber; a strain gauge for the temperature compensation gypsum block is also arranged on the upper surface of the temperature compensation gypsum block; the optical fiber demodulator is also connected with the computer; a connector of the gravity load simulation device is connected with the interior of a dam body of the arch dam physical model, and a lifting sleeve of the oil jack is attached to the surface of the upstream side wall of the arch dam physical model. The device can quickly acquire the surface strain data of the arch dam physical model through the distributed optical fibers. The invention further discloses a strain field reconstruction test method of the arch dam structure and a strain field reconstruction test system of the arch dam structure.

Description

Technical Field

[0001] The invention belongs to the technical field of strain field monitoring of arch dam structures, relates to a strain field reconstruction test device for arch dam structures, and also relates to a strain field reconstruction test system for arch dam structures and a strain field reconstruction test method for arch dam structures. Background Art

[0002] In water conservancy projects, structural mechanics model experiments have become one of the important ways to study arch dam stress, displacement and other issues because they can simulate the actual properties of building foundations as much as possible and consider the influence of various factors. At present, in the arch dam structure experimental models that have been built in many domestic universities and scientific research institutions, strain gauge measurement is still used to measure the strain data of the arch dam. Due to the point-type collection characteristics of strain gauges, it is difficult to reconstruct the strain field with a small amount of strain data or the reconstructed strain field has low accuracy, and thus it is impossible to display the strain information of the arch dam structure as a whole.

[0003] In the process of strain field reconstruction of arch dam, the acquisition of strain data is the most critical. On the one hand, the use of strain gauges to measure the strain data on the surface of the arch dam requires a large number of strain gauges, which increases the cost of model test; on the other hand, the strain gauge measurement method cannot achieve multi-frequency measurement, which increases the complexity of the model test steps. Therefore, in order to solve the strain field reconstruction method of the arch dam structure experimental model and improve the accuracy of the arch dam strain field reconstruction, it has become a practical need. Summary of the invention

[0004] The first object of the present invention is to provide a strain field reconstruction test device for an arch dam structure, which can quickly obtain surface strain data of an arch dam physical model through distributed optical fibers.

[0005] The second object of the present invention is to provide a strain field reconstruction test method for an arch dam structure, which can quickly obtain the surface strain data of the arch dam physical model through distributed optical fibers, reconstruct the strain field through an artificial intelligence algorithm, improve the accuracy of strain field reconstruction, and obtain the strain change law under the action of the arch dam load.

[0006] The third object of the present invention is to provide a strain field reconstruction test system for an arch dam structure.

[0007] The first technical solution adopted by the present invention is a strain field reconstruction test device for an arch dam structure, comprising an arch dam physical model, a temperature compensation gypsum block, an optical fiber and an optical fiber demodulator, wherein the optical fiber is sequentially laid on the upper surface of the arch dam physical model and the upper surface of the temperature compensation gypsum block, the portion of the optical fiber arranged on the arch dam physical model is the first section of the optical fiber, and the portion of the optical fiber arranged on the temperature compensation gypsum block is the second section of the optical fiber; the first end of the optical fiber is connected to the optical fiber demodulator, and the second end is not connected to other devices; a plurality of arch dam physical model strain gauges are also arranged on the upper surface of the arch dam physical model, and the arrangement path of the arch dam physical model strain gauges is consistent with the arrangement path of the first section of the optical fiber; a strain gauge for the temperature compensation gypsum block is also arranged on the upper surface of the temperature compensation gypsum block; the optical fiber demodulator is also connected to a computer; the joint of the gravity load simulation device is connected to the inside of the dam body of the arch dam physical model, and the lifting sleeve of the hydraulic jack is in contact with the upstream side wall surface of the arch dam physical model.

[0008] The second technical solution adopted by the present invention is a strain field reconstruction test method for an arch dam structure, using the above-mentioned device, comprising the following steps:

[0009] Step 1: Locate the strain measurement sites of the arch dam physical model and the temperature compensation gypsum block;

[0010] Step 2: Input the strain data of the arch dam physical model measured by optical fiber into the Savitzky-Golay filter algorithm and perform smoothing to obtain post-processed strain data without abnormalities;

[0011] Step 3: The post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm is interpolated using Kriging interpolation method to obtain the strain field reconstruction method.

[0012] The present invention is also characterized in that:

[0013] Step 1 is as follows:

[0014] Step 1.1: Based on the similarity theory of the prototype arch dam project and model test, the arch dam physical model is made of gypsum material with similar properties to concrete material. At the same time, gypsum blocks consistent with the arch dam physical model material are used to compensate for temperature effects;

[0015] Step 1.2: Several strain gauges for the arch dam physical model, one strain gauge for the temperature compensation gypsum block and optical fibers are arranged on the arch dam physical model and the temperature compensation gypsum block respectively to measure the strain on the surface of the arch dam physical model and the surface of the temperature compensation gypsum block. The portion of the optical fiber arranged on the arch dam physical model is the first section of optical fiber, and the portion of the optical fiber arranged on the temperature compensation gypsum block is the second section of optical fiber. A hydraulic jack is used to apply a water pressure load on the upstream surface of the arch dam physical model according to the water pressure distribution law. The gravity load simulation device applies a downward gravity load using a concentrated force system method based on the Saint-Venant principle.

[0016] The strain measurement part of the arch dam physical model includes the coordinate data set Z1 of m strain gauges used in the arch dam physical model, the coordinate data set Z2 of n equally divided small units constituting the first section of optical fiber, and the optical fiber length data set L1 corresponding to the n small units. The strain measurement part of the temperature compensation gypsum block includes the strain data of a strain gauge used in the temperature compensation gypsum block, and the optical fiber length data set L2 of j equally divided small units constituting the second section of optical fiber.

[0017] Step 1.3: Take a photo of the arch dam physical model and establish a coordinate system to determine the coordinate data set Z1 of each strain gauge for the arch dam physical model and the coordinate data Z2 of the n equally divided small units constituting the first section of optical fiber, where Z1 contains the coordinate data set of m strain gauges for the arch dam physical model as Z1 = (X1, Y1), X1 = [x1, x2, ... x m ] represents the horizontal axis coordinate set of the strain gauges used in the 1st, 2nd, …, mth arch dam physical model, Y1 = [y1, y2, …, y m ] represents the vertical axis coordinate set of the strain gauges used in the 1st, 2nd, …, mth arch dam physical model; Z2 contains the coordinate data set that divides the optical fiber into n small units, which is Z2=(X2,Y2), X2=[x1,x2, …x n ] represents the horizontal axis coordinate of the 1st, 2nd, ..., nth fiber unit, Y2 = [y1, y2, ...y n ] represents the vertical axis coordinate of the 1st, 2nd, ..., nth optical fiber unit;

[0018] Step 1.4: Press the n small units of the first section of optical fiber set on the surface of the arch dam physical model, and determine the fiber length corresponding to the n small units of the first section of optical fiber through the strain data change on the optical fiber demodulator; at the same time, the coordinate data set of the n small units in step 1.3 is matched with the optical fiber length data set L1, and the optical fiber length relationship corresponding to the n coordinate data sets can be determined, Z2→L1=[l1,l2,…l n ];

[0019] Step 1.5: Press the j small units of the second optical fiber set on the surface of the temperature compensation gypsum block, and determine the optical fiber length L2 of the j small units of the optical fiber through the strain data change on the optical fiber demodulator. The j length data set is L2 = [l1, l2, ... l j ].

[0020] Step 2 is as follows:

[0021] Step 2.1: Before the physical test of the arch dam begins, the strains measured by the first and second optical fiber segments need to be leveled; the optical fiber demodulator is preheated, and the optical fiber demodulator is used to scan the strains measured by the first and second optical fiber segments multiple times, and the strain variation range is within ±1.0με.

[0022] Step 2.2: Based on the characteristic water level of the prototype arch dam project, a total of q groups of water level conditions from the dead water level to the check flood level are calculated by similarity theory, and hydraulic jacks are used to apply hydraulic loads step by step to the upstream surface of the arch dam physical model according to the distribution of water pressure;

[0023] Step 2.3: For any water level condition, after the hydraulic jack loads the arch dam physical model for 2 to 3 minutes, record the strain data S1 = [s1, s2, …s m ], and use the fiber demodulator to scan the optical fiber to obtain the strain data of n small units measured by the first section of optical fiber S2 = [s1, s2, ... s n ] and the fiber length set (L1, S2) corresponding to n small unit strain data; at the same time, record the j small unit strain data S measured by the second section of optical fiber on the temperature compensation gypsum block 1a and the fiber length set corresponding to j small unit strain data (L2, S 1a );

[0024] Step 2.4: Use the Savitzky-Golay filter algorithm to smooth the noise of the strain data S2 measured by the first section of optical fiber, where the smoothing formula of the Savitzky-Golay filter algorithm is:

[0025]

[0026] In the formula, s k,smooth h is the strain smoothing value at the center of the strain data smoothing window (-w, w); i is the coefficient of the least squares fitting polynomial; s k+i is the k+ith strain value of the smoothing window (-w, w);

[0027] Step 2.5: Subtract the strain data S1 of the temperature compensation gypsum block measured by the strain gauge from the m strain data S1 of the arch dam physical model measured by the strain gauge to obtain the strain data set S1' of the strain gauge of the arch dam physical model without temperature influence; subtract the strain data S2 of the temperature compensation gypsum block measured by the second section of the optical fiber from the strain data S2 of the first section of the optical fiber. 1a The average value of the strain data set S2' without temperature influence is obtained;

[0028] Step 2.6: After obtaining the strain data S1' measured by m strain gauges at different positions on the physical model of the arch dam and the strain data S2' of the optical fiber on the physical model of the arch dam, determine the corresponding relationship between the strain data of the optical fiber and the coordinate data according to step 1.4, compare the obtained strain data S2' of the optical fiber with the strain data S2' of the optical fiber, and obtain a data set (Z2, S2');

[0029] Step 2.7: After completing one water level condition, repeat steps 2.2-2.6 for the next water level condition, and apply q water level conditions in total, so as to obtain the post-processed strain data sets of q groups of water level conditions.

[0030] Step 3 is as follows:

[0031] Step 3.1: The data sets under the q groups of water level conditions obtained by the optical fiber measurement are interpolated using the Kriging interpolation method. The strain data of the q groups of the first section of the optical fiber obtained under the q groups of water level conditions can be used to reconstruct the strain fields of the q water level conditions. The calculation formula of the Kriging interpolation method is:

[0032]

[0033] In the formula, The reconstructed interpolated strain value at any position o on the arch dam physical model, s i is the strain data measured for the i-th optical fiber unit, λ i is the weight coefficient, which is obtained by weighted summation of the strain data of n strain units.

[0034] Step 3.2: Compare the data set under the q-group water level condition measured by the strain gauge with the accuracy of the reconstructed strain field to ensure that the difference range between the strain value of the strain gauge used in the arch dam physical model and the strain value of the reconstructed strain field at its location satisfies ±2με.

[0035] The third technical solution adopted by the present invention is a strain field reconstruction test system for an arch dam structure, comprising:

[0036] Strain positioning module: locates the strain measurement parts of the arch dam physical model and temperature compensation gypsum block;

[0037] The strain data processing module inputs the strain data of the arch dam physical model measured by optical fiber into the Savitzky-Golay filter algorithm and performs smoothing to obtain post-processed strain data without abnormalities.

[0038] The strain field reconstruction module interpolates the post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm using Kriging interpolation method to obtain the strain field reconstruction method.

[0039] The beneficial effects of the present invention are:

[0040] (1) The device of the present invention can quickly obtain surface strain data of the arch dam physical model through distributed optical fibers.

[0041] (2) The method of the present invention uses the Savitzky-Golay filter algorithm to smooth the noise of the arch dam surface strain data measured by distributed optical fiber, and uses the Kriging interpolation method to reconstruct the strain field data, so that the arch dam surface strain field can be obtained by using distributed optical fiber. On the one hand, the strain data measured by distributed optical fiber is more, which improves the accuracy of strain field reconstruction and is conducive to better understanding the strain field change law of the arch dam model. On the other hand, the device can show the composition and principle of the device to non-professionals, so as to intuitively understand the stress characteristics of the arch dam.

[0042] (3) The method of the present invention can quickly obtain the surface strain data of the arch dam physical model through distributed optical fiber, and reconstruct the strain field through artificial intelligence algorithm to obtain the strain change law under the action of arch dam load, providing an effective and vivid means for the arch dam strain field reconstruction method. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a flow chart of a strain field reconstruction test method for an arch dam structure in Example 1 of the present invention;

[0044] Figure 2 is a structural schematic diagram of a strain field reconstruction test device for an arch dam structure in Example 3 of the present invention;

[0045] Figure 3 is a strain field reconstruction result diagram of the arch dam physical model at a water level of 73.2 cm in Example 1 of the present invention;

[0046] Figure 4 is a strain field reconstruction result diagram of the arch dam physical model at a water level of 88.0 cm in Example 1 of the present invention;

[0047] Figure 5 is a strain field reconstruction result diagram of the arch dam physical model at a water level of 98.8 cm in Example 1 of the present invention;

[0048] Figure 6It is a finite element model of the arch dam physical model established by using the COMSO finite element simulation software in Example 1 of the present invention;

[0049] Figure 7 Embodiment 1 of the present invention Figure 6 The strain field on the downstream surface of the arch dam physical model at A in the middle;

[0050] Figure 8 It is a structural block diagram of the strain field reconstruction system of the arch dam structure in Example 2 of the present invention.

[0051] In the figure, 1. physical model of arch dam; 2. optical fiber, 2-1. first section of optical fiber, 2-2. second section of optical fiber; 3. optical fiber demodulator; 4. strain gauge for physical model of arch dam; 5. strain gauge for temperature compensation gypsum block; 6. temperature compensation gypsum block; 7. computer; 8. gravity load simulation device; 9. hydraulic jack. DETAILED DESCRIPTION

[0052] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] The present invention provides a strain field reconstruction test device for an arch dam structure, comprising an arch dam physical model 1, a temperature compensation gypsum block 6, an optical fiber 2 and an optical fiber demodulator 3, wherein the optical fiber 2 is sequentially laid on the upper surface of the arch dam physical model 1 and the upper surface of the temperature compensation gypsum block 6, the portion of the optical fiber 2 arranged on the arch dam physical model 1 is a first section of optical fiber 2-1, and the portion of the optical fiber 2 arranged on the temperature compensation gypsum block 6 is a second section of optical fiber 2-2; the first end of the optical fiber 2 is connected to the optical fiber demodulator 3, the second end of the optical fiber 2 is not connected to other equipment, and the length of the second end from the temperature compensation gypsum block 6 is 1.5m to 2.0m. A plurality of arch dam physical model strain gauges 4 are also arranged on the upper surface of the arch dam physical model 1, and the spacing between every two arch dam physical model strain gauges 4 is 0.5cm-1cm; the arrangement path of the arch dam physical model strain gauges 4 is consistent with the arrangement path of the first section of optical fiber 2-1; a temperature compensation gypsum block strain gauge 5 is also arranged on the upper surface of the temperature compensation gypsum block 6; the optical fiber demodulator 3 is also connected to the Lenovo computer 7; the joint of the gravity load simulation device 8 is connected to the inside of the dam body of the arch dam physical model 1, and the lifting sleeve of the hydraulic jack 9 is in contact with the upstream side wall surface of the arch dam physical model 1.

[0054] The optical fiber demodulator 3 is an OSI-C optical fiber demodulator;

[0055] The gravity load simulation device 8 is a RSX-30NLT gravity load simulation device.

[0056] The present invention also provides a strain field reconstruction test method for an arch dam structure, using the above-mentioned device, such as Figure 1 As shown, including:

[0057] Step 1: Locate the strain measurement locations of the arch dam physical model 1 and the temperature compensation gypsum block 6;

[0058] Step 1.1: Based on the similarity theory of the prototype arch dam project and model test, the arch dam physical model 1 is made of gypsum material with similar properties to concrete material. At the same time, gypsum blocks with the same material as the arch dam physical model 1 are used to compensate for the temperature effect, such as Figure 2 shown.

[0059] Step 1.2: a plurality of strain gauges 4 for the arch dam physical model, a strain gauge 5 for the temperature compensation gypsum block and an optical fiber 2 are arranged on the arch dam physical model 1 and the temperature compensation gypsum block 6, respectively, to measure the strain on the surface of the arch dam physical model 1 and the surface of the temperature compensation gypsum block 6. The portion of the optical fiber 2 arranged on the arch dam physical model 1 is the first section of the optical fiber 2-1, and the portion of the optical fiber 2 arranged on the temperature compensation gypsum block 6 is the second section of the optical fiber 2-2; and a hydraulic jack 9 is used to apply a water pressure load on the upstream surface of the arch dam physical model 1 according to the water pressure distribution law, and a gravity load simulation device 8 applies a downward gravity load using a concentrated force system method according to the Saint-Venant principle;

[0060] The strain measurement part of the arch dam physical model 1 includes the coordinate data set Z1 of m strain gauges 4 for the arch dam physical model, the coordinate data set Z2 of n equally divided small units constituting the first section of optical fiber 2-1, and the optical fiber length data set L1 corresponding to the n small units. The strain measurement part of the temperature compensation gypsum block 6 includes the strain data of one strain gauge 5 for the temperature compensation gypsum block, and the optical fiber length data set L2 of j equally divided small units constituting the second section of optical fiber 2-2.

[0061] Step 1.3: Take a photo of the arch dam physical model 1 and establish a coordinate system, determine the coordinate data set Z1 of each arch dam physical model strain gauge 4 on the arch dam physical model 1 and the coordinate data Z2 of the n equally divided small units constituting the first section of optical fiber 2-1, where Z1 contains the coordinate data set of m arch dam physical model strain gauges 4 as Z1=X1,Y1, X1=[x1,x2,…x m ] represents the horizontal axis coordinate set of the strain gauge 4 used in the 1st, 2nd, ..., mth arch dam physical model, Y1 = [y1, y2, ..., y m ] represents the vertical axis coordinate set of the strain gauge 4 for the 1st, 2nd, ..., mth arch dam physical model; Z2 includes the coordinate data set that divides the optical fiber into n small units, which is Z2 = X2, Y2, X2 = [x1, x2, ... x n ] represents the horizontal axis coordinate of the 1st, 2nd, ..., nth fiber unit, Y2 = [y1, y2, ...y n ] represents the vertical axis coordinate of the 1st, 2nd, ..., nth optical fiber unit;

[0062] Step 1.4: Press the n small units of the first section of optical fiber 2-1 set on the surface of the arch dam physical model 1, and determine the fiber length corresponding to the n small units of the first section of optical fiber 2-1 through the strain data change on the optical fiber demodulator 3; at the same time, the coordinate data set of the n small units in step 1.3 is matched with the optical fiber length data set L1, and the optical fiber length relationship corresponding to the n coordinate data sets can be determined, Z2→L1=[l1,l2,…l n ];

[0063] Step 1.5: Press the j small units of the second optical fiber 2-2 set on the surface of the temperature compensation gypsum block 6, and determine the optical fiber length L2 of the j small units of the optical fiber through the strain data change on the optical fiber demodulator 3. The j length data set is L2 = [l1, l2, ... l j ].

[0064] Step 2: Input the strain data of the arch dam physical model 1 measured by optical fiber into the Savitzky-Golay filter algorithm, and perform smoothing to obtain post-processed strain data without abnormalities.

[0065] Step 2.1: Before the physical test of the arch dam begins, the strain measured by the first section of optical fiber 2-1 and the second section of optical fiber 2-2 needs to be leveled; the optical fiber demodulator 3 is preheated, and the strain measured by the first section of optical fiber 2-1 and the second section of optical fiber 2-2 is scanned multiple times by the optical fiber demodulator 3, and the strain variation range is within ±1.0με;

[0066] Step 2.2: Based on the characteristic water level of the prototype arch dam project, a total of q groups of water level conditions from the dead water level to the check flood level are calculated by similarity theory, and hydraulic jacks 9 are used to apply hydraulic loads step by step to the upstream surface of the arch dam physical model 1 according to the distribution of water pressure;

[0067] Step 2.3: For any water level condition, after the hydraulic jack loads the arch dam physical model for 2 to 3 minutes, record the strain data S1 = [s1, s2, …s m ], and use the optical fiber demodulator 3 to scan the optical fiber 2 to obtain the strain data S2 of n small units measured by the first section of optical fiber 2-1 = [s1, s2, ... s n ] and the fiber length set (L1, S2) corresponding to n small unit strain data; at the same time, record the j small unit strain data S measured by the second section of optical fiber 2-2 on the temperature compensation gypsum block 6 1a and the fiber length set corresponding to j small unit strain data (L2, S 1a );

[0068] Step 2.4: Use the Savitzky-Golay filter algorithm to smooth the noise of the strain data S2 measured by the first section of optical fiber 2-1, where the smoothing formula of the Savitzky-Golay filter algorithm is:

[0069]

[0070] In the formula, s k,smooth h is the strain smoothing value at the center of the strain data smoothing window (-w, w); i is the coefficient of the least squares fitting polynomial; s k+i is the k+ith strain value of the smoothing window (-w, w);

[0071] Step 2.5: Subtract the strain data S1 of the temperature compensation gypsum block 6 measured by the temperature compensation gypsum block strain gauge 5 from the m strain data S1 measured by the strain gauge 4 of the arch dam physical model to obtain the strain data set S1' of the strain gauge 4 of the arch dam physical model without temperature influence; subtract the strain data S2 measured by the first section of optical fiber 2-1 from the strain data S1 of the temperature compensation gypsum block 6 measured by the second section of optical fiber 2-2. 1a The average value of the strain data set S2' without temperature influence is obtained;

[0072] Step 2.6: After obtaining the strain data S1' measured by the m strain gauges at different positions on the arch dam physical model 1 and the strain data S2' of the optical fiber 2-1 on the arch dam physical model 1, determine the corresponding relationship between the strain data of the optical fiber 2-1 and the coordinate data according to step 1.4, compare the obtained strain data S2' of the optical fiber 2-1 with the strain data S2' of the optical fiber 2-1, and obtain a data set (Z2, S2');

[0073] Step 2.7: After completing one water level condition, repeat steps 2.2-2.6 for the next water level condition, and apply q water level conditions in total, so as to obtain the post-processed strain data sets of q groups of water level conditions.

[0074] Step 3: The post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm is interpolated using Kriging interpolation method to obtain the strain field reconstruction method.

[0075] Specifically, the Kriging interpolation method estimates an optimal, unbiased, and minimum variance interpolation for unknown points by minimizing the sum of squares of prediction errors.

[0076] Step 3.1: The data sets under the q groups of water level conditions obtained by the optical fiber measurement are interpolated using the Kriging interpolation method. The strain data of the q groups of the first section of the optical fiber 2-1 obtained under the q groups of water level conditions can reconstruct the strain field of the q water level conditions. The calculation formula of the Kriging interpolation method is:

[0077]

[0078] In the formula, The reconstructed interpolated strain value at any position o on the arch dam physical model, s i is the strain data measured for the i-th optical fiber unit, λ i is the weight coefficient, which is obtained by weighted summation of the strain data of n strain units.

[0079] Step 3.2: Compare the data set under the q-group water level condition measured by the strain gauge with the accuracy of the reconstructed strain field to ensure that the difference range between the strain value of the strain gauge 4 used in the arch dam physical model and the strain value of the reconstructed strain field at its location satisfies ±2με.

[0080] The feasibility of the reconstructed strain field can be verified by the distribution law of the strain field of the arch dam model calculated by COMSO finite element simulation.

[0081] The present invention also provides a strain field reconstruction test system for an arch dam structure, such as Figure 8 As shown, including:

[0082] Strain positioning module: positioning the strain measurement parts of the arch dam physical model 1 and the temperature compensation gypsum block 6;

[0083] The strain data processing module inputs the strain data of the arch dam physical model 1 measured by optical fiber into the Savitzky-Golay filter algorithm, and performs smoothing to obtain post-processed strain data without abnormalities;

[0084] The strain field reconstruction module interpolates the post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm using Kriging interpolation method to obtain the strain field reconstruction method.

[0085] Example 1

[0086] Step 1: Locate the strain measurement locations of the arch dam physical model 1 and the temperature compensation gypsum block 6.

[0087] Step 1.1: Based on the similarity theory of the prototype arch dam project and model test, the arch dam physical model 1 is made of gypsum material with similar properties to concrete material. At the same time, gypsum blocks with the same material as the arch dam physical model 1 are used to compensate for the temperature effect, such as Figure 2 shown.

[0088] Step 1.2: a plurality of strain gauges 4, strain gauges 5 and optical fibers 2 are arranged on the arch dam physical model 1 and the temperature compensation gypsum block 6, respectively, to measure the strain on the surface of the arch dam physical model 1. The portion of the optical fiber 2 arranged on the arch dam physical model 1 is the first section of optical fiber 2-1, and the portion of the optical fiber 2 arranged on the temperature compensation gypsum block 6 is the second section of optical fiber 2-2; and a hydraulic jack 9 is used to apply a water pressure load on the upstream surface of the arch dam physical model 1 according to the water pressure distribution law, and a gravity load simulation device 8 applies a downward gravity load using a concentrated force system method according to the Saint-Venant principle;

[0089] The strain measurement part of the arch dam physical model 1 includes the coordinate data set Z1 of 25 strain gauges 4, the coordinate data set Z2 of 9000 equally divided small units constituting the first section of optical fiber 2-1, and the optical fiber length data set L1 corresponding to the 9000 small units. The strain measurement part of the temperature compensation gypsum block 6 includes the strain data of 1 strain gauge 5 and the optical fiber length data set L2 of 30 equally divided small units constituting the second section of optical fiber 2-2.

[0090] Step 1.3: Take a photo of the arch dam physical model 1 and establish a coordinate system to determine the coordinate data set Z1 of each strain gauge 4 on the arch dam physical model 1 and the coordinate data Z2 of the 25 equally divided small units constituting the first section 2-1, where Z1 contains the coordinate data set of 25 strain gauges 4 as Z1=(X1,Y1), X1=[x1,x2,…x 25 ] represents the horizontal axis coordinate set of the 1st, 2nd, ..., 25th strain gauge 4, Y1 = [y1, y2, ...y 25 ] represents the vertical axis coordinate set of the 1st, 2nd, ..., 25th strain gauge 4; Z2 contains the coordinate data set that divides the optical fiber into 9000 small units, which is Z2=(X2,Y2), X2=[x1,x2, ...x 9000 ] represents the horizontal axis coordinates of the 1st, 2nd, ..., 9000th fiber units, Y2 = [y1, y2, ...y 9000 ] represents the vertical axis coordinate of the 1st, 2nd,…, 9000th optical fiber units.

[0091] Step 1.4: Press the 9000 small units of the first section of optical fiber 2-1 set on the surface of the arch dam physical model 1, and determine the optical fiber length corresponding to the 9000 small units of the first section of optical fiber 2-1 through the strain data change on the OSI-C optical fiber demodulator 3. At the same time, the coordinate data set of the 9000 small units in step 1.3 is matched with the optical fiber length data set L1, and the optical fiber length relationship corresponding to the 9000 coordinate data sets can be determined, Z2→L1=[l1,l2,…l 9000 ];

[0092] Step 1.5: Press 30 small units of the second section of optical fiber 2-2 set on the surface of the temperature compensation gypsum block 6, and determine the optical fiber length L2 of the 30 small units of optical fiber through the strain data change on the OSI-C optical fiber demodulator 3. The 30 length data sets are L2=[l1,l2,…l 30 ].

[0093] Step 2: Input the strain data of the arch dam physical model 1 measured by optical fiber into the Savitzky-Golay filter algorithm, and perform smoothing to obtain post-processed strain data without abnormalities.

[0094] Step 2.1: Before the physical test of the arch dam begins, the strain measured by the first section of optical fiber 2-1 and the second section of optical fiber 2-2 needs to be leveled; the OSI-C optical fiber demodulator 3 is preheated, and the strain measured by the first section of optical fiber 2-1 and the second section of optical fiber 2-2 is scanned multiple times by the OSI-C optical fiber demodulator 3, and the strain variation range is within ±1.0με;

[0095] Step 2.2: Based on the characteristic water level of the prototype arch dam project, three groups of water level conditions from the dead water level to the verified flood level are calculated by similarity theory, and hydraulic jacks 9 are used to apply hydraulic loads step by step to the upstream surface of the arch dam physical model 1 according to the distribution of water pressure.

[0096] Step 2.3: For any water level condition, after the hydraulic jack loads the arch dam physical model for 2 to 3 minutes, record the strain data S1 = [s1, s2, …s 25 ], and use OSI-C optical fiber demodulator 3 to scan optical fiber 2 to obtain 9000 small units of strain data S2 = [s1, s2, ... s 9000 ] and the optical fiber length set (L1, S2) corresponding to 9000 small unit strain data. At the same time, the 30 small unit strain data S measured by the second section of optical fiber 2-2 on the temperature compensation gypsum block 6 are recorded. 1a and the fiber length set corresponding to 30 small unit strain data (L2, S 1a ).

[0097] Step 2.4: Use the Savitzky-Golay filter algorithm to smooth the noise of the strain data S2 measured by the first section of optical fiber, where the smoothing formula of the Savitzky-Golay filter algorithm is:

[0098]

[0099] In the formula, s k,smooth h is the strain smoothing value at the center of the strain data smoothing window (-w, w); i is the coefficient of the least squares fitting polynomial; sk+i is the k+ith strain value in the smoothing window (-w, w).

[0100] Step 2.5: Subtract the strain data of the temperature-compensated gypsum block measured by strain gauge 5 from the 25 strain data S1 measured by strain gauge 4 to obtain the strain data set S1' of strain gauge 4 without temperature influence; subtract the strain data S2 measured by the first section of optical fiber 2-1 from the strain data S1 of the temperature-compensated gypsum block measured by the second section of optical fiber. 1a The average value of the strain data set S2' without temperature influence is obtained;

[0101] Step 2.6: After obtaining the strain data S1' measured by 25 strain gauges at different positions on the arch dam physical model 1 and the strain data S2' of the optical fiber 2-1 on the arch dam physical model 1, determine the corresponding relationship between the strain data of the optical fiber 2-1 and the coordinate data according to step 1.4, and compare the obtained strain data S2' of the optical fiber 2-1 with the strain data S2' of the optical fiber 2-1 to obtain the data set (Z2, S2')

[0102] Step 2.7: After completing one water level condition, repeat steps 2.2-2.6 for the next water level condition. A total of three water level conditions are applied, thus obtaining three sets of post-processed strain data sets for water level conditions.

[0103] Step 3: The post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm is interpolated using Kriging interpolation method to obtain the strain field reconstruction method.

[0104] Specifically, the Kriging interpolation method estimates an optimal, unbiased, and minimum variance interpolation for unknown points by minimizing the sum of squares of prediction errors.

[0105] Step 3.1: The data sets under the three water level conditions obtained by the optical fiber measurement are interpolated using the Kriging interpolation method respectively. The three water level conditions obtain the three sets of strain data of the optical fiber 2-1. The three sets of strain data of the optical fiber 2-1 can reconstruct the strain fields of the three water level conditions. The calculation formula of the Kriging interpolation method is:

[0106]

[0107] In the formula, The reconstructed interpolated strain value at any position o on the arch dam physical model, s i is the strain data measured for the i-th optical fiber unit, λ i is the weight coefficient, which is obtained by weighted summation of the strain data of 9000 strain units.

[0108] Step 3.2: Compare the accuracy of the three water level data sets obtained by the strain gauges with the reconstructed strain field, such as Figure 3 to Figure 5 As shown. Figures 3 to 5 In the figure, the small white squares are strain gauges of the arch dam physical model, and the values ​​are the strain values ​​at the locations where the strain gauges are arranged. By comparing the strain gauges on the arch dam physical model with the reconstructed strain field cloud map of the arch dam physical model, it is found that the values ​​of the reconstructed strain field cloud map under the three water level conditions are close to the values ​​of the strain gauges at the locations, and the difference range of the strain values ​​is less than ±2με. This phenomenon proves the accuracy of the strain field of the arch dam physical model obtained by the strain reconstruction method.

[0109] The feasibility of the reconstructed strain field can be verified by the distribution law of the strain field of the arch dam model calculated by COMSO finite element simulation, such as Figure 6-7 shown. Figure 6 In order to use the COMSO finite element calculation software, a numerical calculation simulation model consistent with the physical model of the arch dam was established, including the arch dam and the mountain. Figure 7 The downstream strain field distribution of the arch dam physical model A calculated using the COMSO finite element calculation software. The strain distribution law is that the strain value is the largest at the middle bottom and is tensile, and then decreases on both sides and turns to compression, which is consistent with the numerical change law of the reconstructed strain field cloud map of the arch dam physical model.

[0110] Example 2

[0111] like Figure 8 As shown in the figure, the strain field reconstruction test system of the arch dam structure includes:

[0112] Strain positioning module: locates the strain measurement parts of the arch dam physical model and temperature compensation gypsum block;

[0113] The strain data processing module inputs the strain data of the arch dam physical model measured by optical fiber into the Savitzky-Golay filter algorithm and performs smoothing to obtain post-processed strain data without abnormalities.

[0114] The strain field reconstruction module interpolates the post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm using Kriging interpolation method to obtain the strain field reconstruction method.

[0115] Example 3

[0116] like Figure 2As shown, the strain field reconstruction test device of the arch dam structure includes an arch dam physical model 1, a temperature compensation gypsum block 6, an optical fiber 2 and an optical fiber demodulator 3. The optical fiber 2 is laid on the upper surface of the arch dam physical model 1 and the upper surface of the temperature compensation gypsum block 6 in sequence. The portion of the optical fiber 2 arranged on the arch dam physical model 1 is the first section of the optical fiber 2-1, and the portion of the optical fiber 2 arranged on the temperature compensation gypsum block 6 is the second section of the optical fiber 2-2; the first end of the optical fiber 2 is connected to the optical fiber demodulator 3, the second end of the optical fiber 2 is not connected to other equipment, and the length of the second end from the temperature compensation gypsum block 6 is 1.5m to 2.0m. A plurality of arch dam physical model strain gauges 4 are also arranged on the upper surface of the arch dam physical model 1, and the spacing between every two arch dam physical model strain gauges 4 is 0.5cm-1cm; the arrangement path of the arch dam physical model strain gauges 4 is consistent with the arrangement path of the first section of optical fiber 2-1; a temperature compensation gypsum block strain gauge 5 is also arranged on the upper surface of the temperature compensation gypsum block 6; the optical fiber demodulator 3 is also connected to the Lenovo computer 7; the joint of the gravity load simulation device 8 is connected to the inside of the dam body of the arch dam physical model 1, and the lifting sleeve of the hydraulic jack 9 is in contact with the upstream side wall surface of the arch dam physical model 1.

[0117] The specific implementation process is as follows: before the experiment begins, the strain gauge 4 is used to level the arch dam physical model, the optical fiber demodulator 3 is preheated, and the optical fiber 2 is scanned multiple times by the instrument to obtain the initial strain data by measuring the strain. Subsequently, the arch dam physical model 1 is loaded by the hydraulic jack 8, and the dam body is deformed. Then, the strain value of the arch dam physical model 1 is measured by the optical fiber 2 and the strain gauge 4 of the arch dam physical model. Among them, the strain value measured by the optical fiber 2 needs to be analyzed by the optical fiber demodulator 3, and the processed data is input into the Lenovo computer 7, and the strain field of the arch dam is reconstructed by the strain field reconstruction test method.

Claims

1. The strain field reconstruction test device of the arch dam structure is characterized by: The invention comprises an arch dam physical model (1), a temperature compensation gypsum block (6), an optical fiber (2) and an optical fiber demodulator (3); the optical fiber (2) is laid on the upper surface of the arch dam physical model (1) and the upper surface of the temperature compensation gypsum block (6) in sequence; the portion of the optical fiber (2) arranged on the arch dam physical model (1) is a first section of optical fiber (2-1); the portion of the optical fiber (2) arranged on the temperature compensation gypsum block (6) is a second section of optical fiber (2-2); the first end of the optical fiber (2) is connected to the optical fiber demodulator (3), and the second end is not connected to other equipment; the arch dam physical model A plurality of strain gauges (4) of the arch dam physical model are also arranged on the upper surface of the arch dam physical model (1), and the arrangement path of the strain gauges (4) of the arch dam physical model is consistent with the arrangement path of the first section of optical fiber (2-1); a strain gauge (5) for the temperature compensation gypsum block is also arranged on the upper surface of the temperature compensation gypsum block (6); the optical fiber demodulator (3) is also connected to the computer (7); the joint of the gravity load simulation device (8) is connected to the inside of the dam body of the arch dam physical model (1), and the lifting sleeve of the hydraulic jack (9) is in contact with the upstream side wall surface of the arch dam physical model (1).

2. The strain field reconstruction test method of the arch dam structure is characterized by: The device according to claim 1 comprises the following steps: Step 1: Locate the strain measurement locations of the arch dam physical model (1) and the temperature compensation gypsum block (6); Step 2: Input the strain data of the arch dam physical model (1) measured by optical fiber into the Savitzky-Golay filter algorithm and perform smoothing to obtain post-processed strain data without abnormalities; Step 3: The post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm is interpolated using Kriging interpolation method to obtain the strain field reconstruction method.

3. The strain field reconstruction test method of the arch dam structure according to claim 2 is characterized in that: Step 1 is as follows: Step 1.1: Based on the similarity theory of the prototype arch dam project and model test, a gypsum material with similar properties to concrete is used to make an arch dam physical model (1). At the same time, a gypsum block with the same material as the arch dam physical model (1) is used to compensate for the temperature effect; Step 1.2: a plurality of strain gauges (4) for the arch dam physical model, a strain gauge (5) for the temperature compensation gypsum block and an optical fiber (2) are arranged on the arch dam physical model (1) and the temperature compensation gypsum block (6) respectively, so as to measure the strain on the surface of the arch dam physical model (1) and the surface of the temperature compensation gypsum block (6); the portion of the optical fiber (2) arranged on the arch dam physical model (1) is the first section of the optical fiber (2-1), and the portion of the optical fiber (2) arranged on the temperature compensation gypsum block (6) is the second section of the optical fiber (2-2); and a hydraulic jack (9) is used to apply a water pressure load on the upstream surface of the arch dam physical model (1) according to the water pressure distribution law, and a gravity load simulation device (8) applies a downward gravity load by using a concentrated force system method according to Saint-Venant's principle; The strain measurement part of the arch dam physical model (1) includes a coordinate data set Z1 of m strain gauges (4) for the arch dam physical model, a coordinate data set Z2 of n equally divided small units constituting the first section of optical fiber (2-1), and a fiber length data set L1 corresponding to the n small units; the strain measurement part of the temperature compensation gypsum block (6) includes strain data of one strain gauge (5) for the temperature compensation gypsum block, and a fiber length data set L2 of j equally divided small units constituting the second section of optical fiber (2-2); Step 1.3: Take a photo of the arch dam physical model (1) and establish a coordinate system, determine the coordinate data set Z1 of each strain gauge (4) for the arch dam physical model on the arch dam physical model (1) and the coordinate data Z2 of the n equally divided small units constituting the first section of optical fiber (2-1), wherein Z1 contains the coordinate data set of m strain gauges (4) for the arch dam physical model as Z1=(X1, Y1), X1=[x1, x2, … x m ] represents the horizontal axis coordinate set of the strain gauges (4) used in the 1st, 2nd, …, mth arch dam physical model, Y1 = [y1, y2, …, y m ] represents the vertical axis coordinate set of the 1st, 2nd, ..., mth strain gauges (4) used in the physical model of the arch dam; Z2 includes the coordinate data set that divides the optical fiber into n small units, which is Z2 = (X2, Y2), X2 = [x1, x2, ... x n ] represents the horizontal axis coordinate of the 1st, 2nd, ..., nth fiber unit, Y2 = [y1, y2, ...y n ] represents the vertical axis coordinate of the 1st, 2nd, ..., nth optical fiber unit; Step 1.4: Press the n small units of the first section of optical fiber (2-1) arranged on the surface of the arch dam physical model (1), and determine the optical fiber length corresponding to the n small units of the first section of optical fiber (2-1) through the change of strain data on the optical fiber demodulator (3); at the same time, correspond the coordinate data set of the n small units in step 1.3 to the optical fiber length data set L1, and then determine the optical fiber length relationship corresponding to the n coordinate data sets, Z2→L1=[l1,l2,…l n ]; Step 1.5: Press the j small units of the second optical fiber (2-2) arranged on the surface of the temperature compensation gypsum block (6), and determine the optical fiber length L2 of the j small units of the optical fiber through the strain data change on the optical fiber demodulator (3). The j length data set is L2 = [l1, l2, ... l j ].

4. The strain field reconstruction test method of the arch dam structure according to claim 3 is characterized in that: Step 2 is as follows: Step 2.1: Before the physical test of the arch dam begins, the strain measured by the first section of optical fiber (2-1) and the second section of optical fiber (2-2) needs to be leveled; the optical fiber demodulator (3) is preheated, and the strain measured by the first section of optical fiber (2-1) and the second section of optical fiber (2-2) is scanned multiple times using the optical fiber demodulator (3), and the strain variation range is within ±1.0με; Step 2.2: Based on the characteristic water level of the prototype arch dam project, a total of q groups of water level conditions from the dead water level to the check flood level are calculated by similarity theory, and a hydraulic jack (9) is used to apply a hydraulic load step by step to the upstream surface of the arch dam physical model (1) according to the distribution of water pressure; Step 2.3: For any water level condition, after the hydraulic jack loads the arch dam physical model for 2 to 3 minutes, record the strain data S1 = [s1, s2, ...s m ], and use the optical fiber demodulator (3) to scan the optical fiber (2) to obtain the strain data S2 = [s1, s2, ... s n ] and the optical fiber length set (L1, S2) corresponding to n small unit strain data; at the same time, record the j small unit strain data S measured by the second section of optical fiber (2-2) on the temperature compensation gypsum block (6) 1a and the fiber length set corresponding to j small unit strain data (L2, S 1a ); Step 2.4: Use the Savitzky-Golay filter algorithm to smooth the noise of the strain data S2 measured by the first section of optical fiber (2-1), where the smoothing formula of the Savitzky-Golay filter algorithm is: In the formula, s k,smooth h is the strain smoothing value at the center of the strain data smoothing window (-w, w); i is the coefficient of the least squares fitting polynomial; s k+i is the k+ith strain value of the smoothing window (-w, w); Step 2.5: The m strain data S1 measured by the strain gauge (4) for the arch dam physical model are subtracted from the strain data of the temperature compensation gypsum block (6) measured by the strain gauge (5) for the temperature compensation gypsum block to obtain a strain data set S1' of the strain gauge (4) for the arch dam physical model without temperature influence; the strain data S2 measured by the first section of optical fiber (2-1) are subtracted from the strain data S1' of the temperature compensation gypsum block (6) measured by the second section of optical fiber (2-2). 1a The average value of the strain data set S2' without temperature influence is obtained; Step 2.6: After obtaining the strain data S1' measured by m strain gauges at different positions on the arch dam physical model (1) and the strain data S2' of the optical fiber (2-1) on the arch dam physical model (1), determine the corresponding relationship between the strain data of the optical fiber (2-1) and the coordinate data according to step 1.4, compare the obtained strain data S2' of the optical fiber (2-1) with the strain data S2' of the optical fiber (2-1), and obtain a data set (Z2, S2'); Step 2.7: After completing one water level condition, repeat steps 2.2-2.6 for the next water level condition, and apply q water level conditions in total, so as to obtain the post-processed strain data sets of q groups of water level conditions.

5. The strain field reconstruction test method of the arch dam structure according to claim 3 is characterized in that: Step 3 is as follows: Step 3.1: The data sets under the q groups of water level conditions obtained by the optical fiber measurement are interpolated using the Kriging interpolation method. The strain data of the q groups of the first section of optical fiber (2-1) obtained under the q groups of water level conditions can reconstruct the strain field of the q water level conditions. The calculation formula of the Kriging interpolation method is: In the formula, The reconstructed interpolated strain value at any position o on the arch dam physical model, s i is the strain data measured for the i-th optical fiber unit, λ i is the weight coefficient, obtained by weighted summation of strain data of n strain units; Step 3.2: Compare the data set under the q-group water level condition measured by the strain gauge with the accuracy of the reconstructed strain field to ensure that the difference range between the strain value of the strain gauge (4) used in the arch dam physical model and the strain value of the reconstructed strain field at its location satisfies ±2με.

6. The strain field reconstruction test system of the arch dam structure is characterized by: include: Strain positioning module: positioning the strain measurement position of the arch dam physical model (1) and the temperature compensation gypsum block (6); The strain data processing module inputs the strain data of the arch dam physical model (1) measured by optical fiber into the Savitzky-Golay filter algorithm and performs smoothing to obtain post-processed strain data without abnormalities; The strain field reconstruction module interpolates the post-processed strain data set obtained by optical fiber measurement and Savitzky-Golay filter algorithm using Kriging interpolation method to obtain the strain field reconstruction method.

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