A method and system for dynamic identification of longitudinal bending stiffness of prefabricated station

Abstract

The invention relates to the technical field of subway station assembly, and discloses a method and system for dynamically identifying the longitudinal bending stiffness of an assembled station. The method comprises: selecting a monitoring pipe section in the assembled station, and selecting a monitoring ring section in the monitoring pipe section, wherein the monitoring ring section is a section in the monitoring pipe section that is perpendicular to the axis of the monitoring pipe section; monitoring the radial deformation of the monitoring ring section, and monitoring the longitudinal strain of the monitoring pipe section at the monitoring ring section, and determining the bending moment of the monitoring ring section according to the radial deformation of the monitoring ring section and the longitudinal strain of the monitoring pipe section at the monitoring ring section; determining the equivalent bending stiffness at the monitoring ring section according to an equivalent bending stiffness calculation formula and the bending moment of the monitoring ring section, and taking the equivalent bending stiffness at the monitoring ring section as the longitudinal bending stiffness of the assembled station.

Description

Technical Field

[0001] The invention relates to the technical field of subway station assembly, and in particular to a method and system for dynamically identifying the longitudinal bending stiffness of an assembled station. Background Art

[0002] With the rapid advancement of urbanization, the development of underground space in large cities has become an important part of urban planning. In traditional open-cut construction, subway stations usually use cast-in-place technology, but this method has problems such as large labor demand and difficult to control construction quality. Since prefabricated components are made in factories, the construction quality can be better controlled and the reliability and stability of the project can be improved. The use of prefabricated assembly technology in the construction process of subway stations can significantly improve construction efficiency.

[0003] In view of the particularity of the cross-section of quasi-rectangular prefabricated subway stations and the complexity of construction design, the current research on prefabricated components focuses on the performance of circumferential joints, and there are fewer studies on the dynamic changes of the longitudinal bending stiffness of quasi-rectangular prefabricated subway stations. In fact, prefabricated stations are usually assembled from multiple rings of prefabricated components. Different blocks of prefabricated components in each ring may undergo certain settlement or horizontal convergence. These factors will cause the structure to change over time, that is, the longitudinal bending stiffness has the characteristics of nonlinear changes over time. Whether the dynamic changes of the longitudinal bending stiffness of prefabricated subway stations can be obtained in time to determine whether the single-ring prefabricated components of prefabricated subway stations are currently in a safe state is the key to ensuring the safe operation of prefabricated subway stations.

[0004] Therefore, there is an urgent need for a dynamic identification method and system for the longitudinal bending stiffness of prefabricated stations to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a method and system for dynamically identifying the longitudinal bending stiffness of an assembled subway station, which can timely obtain the dynamic changes of the longitudinal bending stiffness of an assembled subway station.

[0006] In order to achieve the above object, the present invention provides a method for dynamically identifying the longitudinal bending stiffness of an assembled station, wherein the assembled station includes a plurality of pipe sections spliced ​​in sequence, wherein the pipe sections include a top plate and a bottom plate arranged relatively up and down, and a left plate and a right plate arranged relatively left and right, characterized in that it includes:

[0007] Select a monitoring pipe section in the prefabricated station, and select a monitoring ring section in the monitoring pipe section. The monitoring ring section is a section in the monitoring pipe section that is perpendicular to the axis of the monitoring pipe section.

[0008] Monitor the radial deformation of the monitoring ring cross section, and monitor the longitudinal strain of the monitoring pipe section at the monitoring ring cross section, and determine the bending moment of the monitoring ring cross section according to the radial deformation of the monitoring ring cross section and the longitudinal strain of the monitoring pipe section at the monitoring ring cross section;

[0009] According to the calculation formula of equivalent bending stiffness and the bending moment of the monitoring ring section, the equivalent bending stiffness at the monitoring ring section is determined, and the equivalent bending stiffness at the monitoring ring section is used as the longitudinal bending stiffness of the prefabricated station.

[0010] As an improvement of the above technical solution, the monitoring ring cross section includes a top plate cross section, a bottom plate cross section, a left plate cross section and a right plate cross section;

[0011] Monitor the radial deformation of the monitoring ring section, including:

[0012] Select a first monitoring point on the inner contour of the bottom plate section, select a second monitoring point on the inner contour of the top plate section, select a third monitoring point on the inner contour of the left plate section, and select a fourth monitoring point on the inner contour of the right plate section. The first monitoring point is located at the center of the inner contour of the top plate section in the length direction, the second monitoring point is located at the center of the inner contour of the bottom plate section in the length direction, the third monitoring point is located at the center of the inner contour of the left plate section in the length direction, and the fourth monitoring point is located at the center of the inner contour of the right plate section in the length direction;

[0013] The radial displacements of the first monitoring point, the second monitoring point, the third monitoring point and the fourth monitoring point along the monitoring pipe section are monitored respectively.

[0014] As an improvement of the above technical solution, the longitudinal strain at the cross section of the monitoring ring is monitored, including:

[0015] The longitudinal strains of the top plate and the bottom plate are monitored separately by the strain monitoring device.

[0016] As an improvement of the above technical solution, the longitudinal strain of the top plate and the bottom plate is monitored respectively by a strain monitoring device, including:

[0017] A first crack meter is used to monitor the distance between a first fixed point and a second fixed point on the inner contour of the monitoring pipe section, the first fixed point and the second fixed point are spaced apart along the axial direction of the monitoring pipe section, and a line connecting the first fixed point and the second fixed point on the inner contour of the monitoring pipe section passes through the first monitoring point; a second crack meter is used to monitor the distance between a third fixed point and a fourth fixed point on the inner contour of the monitoring pipe section, the third fixed point and the fourth fixed point are spaced apart along the axial direction of the monitoring pipe section, and a line connecting the third fixed point and the fourth fixed point on the inner contour of the monitoring pipe section passes through the second monitoring point;

[0018] The longitudinal strain at the centroid of the top plate cross section is determined according to the change in distance between the first fixed point and the second fixed point, and the longitudinal strain at the centroid of the bottom plate cross section is determined according to the change in distance between the third fixed point and the fourth fixed point. The centroid of the top plate cross section and the centroid of the bottom plate cross section are both located on the straight line determined by the first monitoring point and the second monitoring point.

[0019] As an improvement of the above technical solution, the calculation formula of the longitudinal strain at the centroid of the bottom plate section is:

[0020]

[0021] Among them, ε c1 is the longitudinal strain at the centroid of the bottom plate section; ε c2 is the longitudinal strain at the centroid of the top plate section; δ1 is the current distance between the first fixed point and the second fixed point; δ 10 is the initial distance between the first fixed point and the second fixed point; T1 is the distance between the centroid of the top plate section and the origin of the coordinate system. The centroid of the top plate section is located on the straight line where the first monitoring point and the second monitoring point are located, and is located at the midpoint of the thickness direction of the top plate; T2 is the distance between the centroid of the bottom plate section and the origin of the coordinate system. The centroid of the bottom plate section is located on the straight line where the first monitoring point and the second monitoring point are located, and is located at the midpoint of the thickness direction of the bottom plate; t1′ is the distance between the centroid of the top plate section and the first monitoring point; t2′ is the distance between the centroid of the bottom plate section and the second monitoring point;

[0022] The calculation formula for the longitudinal strain at the centroid of the top plate section is:

[0023]

[0024] Among them, ε c2 is the longitudinal strain at the centroid of the top plate section; δ2 is the current distance between the third fixed point and the fourth fixed point; δ 20 is the initial distance between the third fixed point and the fourth fixed point.

[0025] As an improvement of the above technical solution, after selecting the monitoring ring section in the monitoring pipe section, it also includes:

[0026] Selecting a first coordinate invariant point, a second coordinate invariant point, a third coordinate invariant point and a fourth coordinate invariant point on the cross section of the monitoring ring;

[0027] A coordinate system is established with the centroid of the outer contour of the monitoring ring cross section as the origin, the Y axis of the coordinate system passes through the first monitoring point and the second monitoring point, and the X axis of the coordinate system passes through the third monitoring point and the fourth monitoring point;

[0028] The coordinates of the first coordinate invariant point, the second coordinate invariant point, the third coordinate invariant point and the fourth coordinate invariant point on the coordinate system are determined.

[0029] As an improvement of the above technical solution, the first coordinate invariant point is located at the joint of the top plate and the left plate, and is located at the center of the top plate in the thickness direction and the center of the left plate in the thickness direction. The second coordinate invariant point is located at the joint of the left plate and the bottom plate, and is located at the center of the left plate in the thickness direction and the center of the bottom plate in the thickness direction. The third coordinate invariant point is located at the joint of the bottom plate and the right plate, and is located at the center of the bottom plate in the thickness direction and the center of the right plate in the thickness direction. The fourth coordinate invariant point is located at the joint of the right plate and the top plate, and is located at the center of the right plate in the thickness direction and the center of the top plate in the thickness direction.

[0030] As an improvement of the above technical solution, the bending moment of the monitoring ring section is determined according to the radial deformation of the monitoring ring section and the longitudinal strain of the monitoring pipe section at the monitoring ring section, including:

[0031] According to the displacement of the first monitoring point, the second monitoring point, the third monitoring point and the fourth monitoring point along the radial direction of the monitoring pipe section, the current coordinates of the centroid of the bottom plate cross section, the centroid of the top plate cross section, the centroid of the left plate cross section and the centroid of the right plate cross section on the coordinate system are determined respectively;

[0032] According to the current coordinates of the centroid of the top plate cross section, the coordinates of the first coordinate invariant point and the coordinates of the fourth coordinate invariant point, a quadratic curve fitting is performed on the centroid of the top plate cross section, the first coordinate invariant point and the fourth coordinate invariant point to obtain the top plate cross section expression;

[0033] According to the current coordinates of the centroid of the bottom plate cross section, the coordinates of the second coordinate invariant point and the coordinates of the third coordinate invariant point, a quadratic curve fitting is performed on the centroid of the bottom plate cross section, the second coordinate invariant point and the third coordinate invariant point to obtain the bottom plate cross section expression;

[0034] According to the current coordinates of the centroid of the left plate section, the coordinates of the first coordinate invariant point and the coordinates of the second coordinate invariant point, a quadratic curve fitting is performed on the centroid of the left plate section, the first coordinate invariant point and the second coordinate invariant point to obtain the expression of the left plate section;

[0035] According to the current coordinates of the centroid of the right plate cross section, the coordinates of the third coordinate invariant point and the coordinates of the fourth coordinate invariant point, a quadratic curve fitting is performed on the centroid of the right plate cross section, the third coordinate invariant point and the fourth coordinate invariant point to obtain the expression of the right plate cross section;

[0036] According to the top plate section expression, the bottom plate section expression, the left plate section expression, the right plate section expression, the longitudinal strain at the centroid of the top plate section, and the longitudinal strain at the centroid of the bottom plate section, the axial force balance equation and the moment balance equation of the monitoring ring section are established;

[0037] The bending moment on the monitoring ring section is determined based on the axial force balance equation and moment balance equation on the monitoring ring section.

[0038] As an improvement of the above technical solution, the equivalent bending stiffness calculation formula is:

[0039]

[0040] Among them, (EI) eq is the equivalent bending stiffness of the continuous beam; M is the bending moment of the monitoring ring section.

[0041] A system for dynamically identifying the longitudinal bending stiffness of an assembled station uses any of the methods for dynamically identifying the longitudinal bending stiffness of an assembled station described above to dynamically monitor the longitudinal bending stiffness of the assembled station.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The method and system for dynamically identifying the longitudinal bending stiffness of an assembled station of the present invention monitors the longitudinal strain of a pipe section at a monitoring ring section in real time, and monitors the radial deformation of the monitoring ring section, thereby determining the bending moment experienced by the monitoring ring section, and then determining the equivalent bending stiffness at the monitoring ring section based on a calculation formula for the equivalent bending stiffness of a continuous beam and the bending moment experienced by the monitoring ring section, and using the equivalent bending stiffness at the monitoring ring section as the longitudinal bending stiffness of the assembled station, thereby timely obtaining the dynamic changes in the longitudinal bending stiffness of the assembled subway station, thereby determining whether the single-ring prefabricated components of the assembled subway station are currently in a safe state, and ensuring the safe operation of the assembled subway station. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic diagram of a monitoring ring cross section of a monitoring pipe section of an assembled station provided by an embodiment of the present invention;

[0045] Figure 2 It is a longitudinal deformation and stress distribution diagram of the ring section of the assembled station provided by the embodiment of the present invention;

[0046] Figure 3 A side view of a monitoring pipe section of an assembled station provided by an embodiment of the present invention after operation for a period of time.

[0047] In the figure:

[0048] 1. Top plate; 2. Bottom plate; 3. Right plate; 4. Left plate;

[0049] 10, first monitoring point; 20, second monitoring point; 30, third monitoring point; 40, fourth monitoring point;

[0050] 50, centroid of the top plate cross section; 60, centroid of the bottom plate cross section; 70, centroid of the left plate cross section; 80, centroid of the right plate cross section;

[0051] 90, first fixed point; 100, second fixed point; 110, third fixed point; 120, fourth fixed point. DETAILED DESCRIPTION

[0052] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0053] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0055] In the description of this embodiment, the terms "upper", "lower", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0056] This embodiment provides a method for dynamically identifying the longitudinal bending stiffness of a prefabricated station. Figure 1 As shown, the prefabricated station includes a plurality of pipe sections spliced ​​in sequence, the pipe sections include a top plate 1 and a bottom plate 2 arranged relatively up and down, and a left plate 4 and a right plate 3 arranged relatively left and right. The dynamic identification method of the longitudinal bending stiffness of the prefabricated station includes:

[0057] Select a monitoring pipe section in the prefabricated station, and select a monitoring ring section in the monitoring pipe section. The monitoring ring section is a section in the monitoring pipe section that is perpendicular to the axis of the monitoring pipe section.

[0058] The radial deformation of the monitoring ring cross section is monitored, and the longitudinal strain of the monitoring pipe section at the monitoring ring cross section is monitored, and the bending moment of the monitoring ring cross section is determined according to the radial deformation of the monitoring ring cross section and the longitudinal strain of the monitoring pipe section at the monitoring ring cross section. The radial direction in this embodiment refers to the radial direction of the monitoring pipe section, and the longitudinal direction in this embodiment refers to the axial direction of the monitoring pipe section;

[0059] According to the calculation formula of equivalent bending stiffness of continuous beam, the axial force and bending moment of monitoring ring section, the equivalent bending stiffness at monitoring ring section is determined, and the equivalent bending stiffness at monitoring ring section is used as the longitudinal bending stiffness of prefabricated station.

[0060] The method for dynamic identification of longitudinal bending stiffness of prefabricated stations provided in this embodiment monitors the longitudinal strain of the pipe section at the monitoring ring section in real time, and monitors the radial deformation of the monitoring ring section, so as to determine the bending moment exerted on the monitoring ring section, and then determine the equivalent bending stiffness at the monitoring ring section according to the calculation formula of the equivalent bending stiffness of the continuous beam and the bending moment exerted on the monitoring ring section, and use the equivalent bending stiffness at the monitoring ring section as the longitudinal bending stiffness of the prefabricated station, so as to timely obtain the dynamic changes of the longitudinal bending stiffness of the prefabricated subway station, so as to judge whether the single-ring prefabricated components of the prefabricated subway station are currently in a safe state, so as to ensure the safe operation of the prefabricated subway station.

[0061] The pipe segment structural parameters in this embodiment are as follows:

[0062] Table 1 Structural design parameters of assembled components

[0063]

[0064]

[0065] It can be understood by those skilled in the art that during the normal operation stage, the prefabricated station is under full cross-section compression, and the compression deformation of the bottom plate of the pipe section is smaller than the compression deformation of the top plate. After the prefabricated station has been running for a period of time, the side view of the monitoring pipe section is as follows: Figure 3 As shown, since the compression deformation of the bottom plate of the pipe section is smaller than the compression deformation of the top plate, the monitoring pipe section as a whole is in an upward bending state.

[0066] Since the pipe section includes a top plate 1 and a bottom plate 2 arranged opposite to each other vertically, and a left plate 4 and a right plate 3 arranged opposite to each other horizontally, the monitoring ring cross section includes a top plate cross section, a bottom plate cross section, a left plate cross section and a right plate cross section.

[0067] Optionally, monitoring the radial deformation of the ring cross section includes monitoring the radial deformation of the top plate cross section, monitoring the radial deformation of the bottom plate 2, monitoring the radial deformation of the left plate 4, and monitoring the radial deformation of the right plate 3, specifically including:

[0068] A first monitoring point 10 is selected on the inner contour of the bottom plate cross section, a second monitoring point 20 is selected on the inner contour of the top plate cross section, a third monitoring point 30 is selected on the inner contour of the left plate cross section, and a fourth monitoring point 40 is selected on the inner contour of the right plate cross section. In this embodiment, the first monitoring point 10 is located at the center of the inner contour of the top plate cross section in the length direction, the second monitoring point 20 is located at the center of the inner contour of the bottom plate cross section in the length direction, the third monitoring point 30 is located at the center of the inner contour of the left plate cross section in the length direction, and the fourth monitoring point 40 is located at the center of the inner contour of the right plate cross section in the length direction;

[0069] The radial displacements of the first monitoring point 10, the second monitoring point 20, the third monitoring point 30 and the fourth monitoring point 40 along the monitoring pipe section are monitored respectively.

[0070] Those skilled in the art can understand that, during the normal operation stage of the prefabricated station, the radial deformation of the pipe section is mainly caused by the pressure on the outer wall of the pipe section, and the top plate 1, the bottom plate 2, the left plate 4 and the right plate 3 are deformed along the radial direction of the pipe section, and the radial deformation is the largest at the center of the width direction of the top plate 1, the radial deformation is the largest at the center of the width direction of the bottom plate 2, the radial deformation is the largest at the center of the height direction of the left plate 4 on the left plate 4, and the radial deformation of the center of the height direction of the right plate 3 on the right plate 3 is the largest at the center, and the radial deformation of the joints of the top plate 1 and the left plate 4, the joints of the top plate 1 and the right plate 3, the joints of the bottom plate 2 and the left plate 4, and the joints of the bottom plate 2 and the right plate 3 are close to zero, and these four joints can be regarded as no radial deformation. Therefore, in this embodiment, the first monitoring point 10 is selected at the center of the inner contour length direction of the top plate cross section, the second monitoring point 20 is selected at the center of the inner contour length direction of the bottom plate cross section, the third monitoring point 30 is selected at the center of the inner contour length direction of the left plate cross section, and the fourth monitoring point 40 is selected at the center of the inner contour length direction of the right plate cross section, and the displacements at the first monitoring point 10, the second monitoring point 20, the third monitoring point 30 and the fourth monitoring point 40 are monitored by a laser rangefinder.

[0071] Optionally, monitoring the longitudinal strain at the cross section of the monitoring ring includes: monitoring the longitudinal strain of the top plate 1 and the bottom plate 2 respectively through a strain monitoring device. In this embodiment, the strain monitoring device is a crack meter. In other embodiments, other types of strain monitoring devices may also be used.

[0072] Further, the longitudinal strains of the top plate 1 and the bottom plate 2 are respectively monitored by the strain monitoring device, including: using a first crack meter to monitor the distance between a first fixed point 90 and a second fixed point 100 on the inner contour of the monitoring pipe section, the first fixed point 90 and the second fixed point 100 are arranged at intervals along the axial direction of the monitoring pipe section, the line connecting the first fixed point 90 and the second fixed point 100 on the inner contour of the monitoring pipe section passes through the first monitoring point 10, and the first fixed point 90 and the second fixed point 100 are both located at the center of the width direction of the top plate 1; using a second crack meter to monitor the distance between a third fixed point 110 and a fourth fixed point 120 on the inner contour of the monitoring pipe section, the third fixed point 110 and the fourth fixed point 120 are arranged at intervals along the axial direction of the monitoring pipe section, the line connecting the third fixed point 110 and the fourth fixed point 120 on the inner contour of the monitoring pipe section passes through the second monitoring point 20, and the first fixed point 110 and the second fixed point 120 are both located at the center of the width direction of the bottom plate 2;

[0073] The longitudinal strain at the centroid 50 of the top plate cross section is determined according to the change in distance between the first fixed point 90 and the second fixed point 100, and the longitudinal strain at the centroid 60 of the bottom plate cross section is determined according to the change in distance between the third fixed point 110 and the fourth fixed point 120. The centroid 50 of the top plate cross section and the centroid 60 of the bottom plate cross section are both located on the straight line determined by the first monitoring point 10 and the second monitoring point 20.

[0074] Furthermore, the longitudinal strain calculation formula at the centroid 60 of the bottom plate section is:

[0075]

[0076] Among them, ε c1 is the longitudinal strain at the centroid 60 of the bottom plate section; ε c2 is the longitudinal strain at the centroid 50 of the top plate section; δ1 is the current distance between the first fixed point 90 and the second fixed point 100 (that is, the current reading of the first crack meter); δ 10is the initial distance between the first fixed point 90 and the second fixed point 100 (that is, the initial reading of the first crack meter); T1 is the distance between the centroid 50 of the top plate section and the origin of the coordinate system. The centroid 50 of the top plate section is located on the straight line where the first monitoring point 10 and the second monitoring point 20 are located, and is located at the midpoint of the thickness direction of the top plate 1; T2 is the distance between the centroid 60 of the bottom plate section and the origin of the coordinate system. The centroid 60 of the bottom plate section is located on the straight line where the first monitoring point 10 and the second monitoring point 20 are located, and is located at the midpoint of the thickness direction of the bottom plate 2; t1′ is the distance between the centroid 50 of the top plate section and the first monitoring point 10; t2′ is the distance between the centroid 60 of the bottom plate section and the second monitoring point 20;

[0077] The calculation formula for the longitudinal strain at the centroid 50 of the top plate section is:

[0078]

[0079] Among them, ε c2 is the longitudinal strain at the centroid 50 of the top plate cross section; δ2 is the current distance between the third fixed point 110 and the fourth fixed point 120 (that is, the current reading of the second crack meter); δ 20 is the initial distance between the third fixed point 110 and the fourth fixed point 120 (that is, the initial reading of the second crack meter). In this embodiment, δ 20 With δ 10 equal.

[0080] Optionally, after selecting the monitoring ring section in the monitoring pipe section, the following steps are also included:

[0081] Selecting a first coordinate invariant point, a second coordinate invariant point, a third coordinate invariant point and a fourth coordinate invariant point on the cross section of the monitoring ring;

[0082] A coordinate system is established with the centroid of the outer contour of the monitoring ring cross section as the origin, the Y axis of the coordinate system passes through the first monitoring point 10 and the second monitoring point 20, and the X axis of the coordinate system passes through the third monitoring point 30 and the fourth monitoring point 40;

[0083] The coordinates of the first coordinate invariant point, the second coordinate invariant point, the third coordinate invariant point and the fourth coordinate invariant point on the coordinate system are determined.

[0084] Further, the first coordinate invariant point is located at the joint of the top plate 1 and the left plate 4, and is located at the center of the thickness direction of the top plate 1 and the center of the thickness direction of the left plate 4. The second coordinate invariant point is located at the joint of the left plate 4 and the bottom plate 2, and is located at the center of the thickness direction of the left plate 4 and the center of the thickness direction of the bottom plate 2. The third coordinate invariant point is located at the joint of the bottom plate 2 and the right plate 3, and is located at the center of the thickness direction of the bottom plate 2 and the center of the thickness direction of the right plate 3. The fourth coordinate invariant point is located at the joint of the right plate 3 and the top plate 1, and is located at the center of the thickness direction of the right plate 3 and the center of the thickness direction of the top plate 1.

[0085] Optionally, determining the bending moment of the monitoring ring section according to the radial deformation of the monitoring ring section and the longitudinal strain of the monitoring pipe section at the monitoring ring section includes:

[0086] According to the displacement of the first monitoring point 10, the second monitoring point 20, the third monitoring point 30 and the fourth monitoring point 40 along the radial direction of the monitoring pipe section, the current coordinates of the bottom plate cross-section centroid 60, the top plate cross-section centroid 50, the left plate cross-section centroid 70 and the right plate cross-section centroid 80 on the coordinate system are determined respectively. It can be understood by those skilled in the art that the initial coordinates of the first monitoring point 10, the second monitoring point 20, the third monitoring point 30 and the fourth monitoring point 40 are all known, and the first monitoring point 10 and the second monitoring point 20 are only displaced along the Y-axis direction, and the third monitoring point 30 and the fourth monitoring point 40 are only displaced along the X-axis direction. Therefore, after obtaining the displacement of the first monitoring point 10, the second monitoring point 20, the third monitoring point 30 and the fourth monitoring point 40, the current coordinates of the first monitoring point 10, the second monitoring point 20, the third monitoring point 30 and the fourth monitoring point 40 can be obtained. The current ordinate of the first monitoring point 10 minus half of the thickness of the bottom plate 2 can be obtained to obtain the current ordinate of the centroid 60 of the bottom plate cross section, and the current abscissa of the centroid 60 of the bottom plate cross section is the same as the abscissa of the first monitoring point 10. The current ordinate of the second monitoring point 20 plus half of the thickness of the top plate 1 can be obtained to obtain the current ordinate of the centroid 50 of the top plate cross section, and the current abscissa of the centroid 50 of the top plate cross section is the same as the current abscissa of the second monitoring point 20. The current abscissa of the third monitoring point 30 minus half of the thickness of the left plate 3 can be obtained to obtain the current abscissa of the centroid 70 of the left plate cross section, and the current ordinate of the centroid 70 of the left plate cross section is the same as the current ordinate of the third monitoring point 30. The current abscissa of the fourth monitoring point 40 plus half of the thickness of the right plate 4 can be obtained to obtain the current abscissa of the centroid 80 of the right plate cross section, and the current ordinate of the centroid 80 of the right plate cross section is the same as the current ordinate of the fourth monitoring point;

[0087] According to the current coordinates of the top plate cross section centroid 50, the coordinates of the first coordinate invariant point and the coordinates of the fourth coordinate invariant point, a quadratic curve fitting is performed on the top plate cross section centroid 50, the first coordinate invariant point and the fourth coordinate invariant point to obtain the top plate cross section expression; in this embodiment, the top plate cross section expression is: y1 = a1x 2 +T1'; wherein T1' is the current ordinate of the centroid 50 of the top plate cross section. It can be understood by those skilled in the art that the abscissa of the centroid 50 of the top plate cross section is always zero;

[0088] According to the current coordinates of the centroid 60 of the bottom plate cross section, the coordinates of the second coordinate invariant point and the coordinates of the third coordinate invariant point, a quadratic curve fitting is performed on the centroid 60 of the bottom plate cross section, the second coordinate invariant point and the third coordinate invariant point to obtain the bottom plate cross section expression; the bottom plate cross section expression is y2=a2x 2 -T2'; wherein T2' is the current ordinate of the centroid 60 of the bottom plate cross section. It can be understood by those skilled in the art that the abscissa of the centroid 60 of the bottom plate cross section is always zero;

[0089] According to the current coordinates of the centroid 70 of the left plate cross section, the coordinates of the first coordinate invariant point and the coordinates of the second coordinate invariant point, a quadratic curve fitting is performed on the centroid 70 of the left plate cross section, the first coordinate invariant point and the second coordinate invariant point to obtain the expression of the left plate cross section; the expression of the left plate cross section is x1=a3y-T3'; wherein T3' is the current abscissa of the centroid 70 of the left plate cross section, and it can be understood by those skilled in the art that the ordinate of the centroid 70 of the left plate cross section is always zero;

[0090] According to the current coordinates of the centroid 80 of the right plate cross section, the coordinates of the third coordinate invariant point and the coordinates of the fourth coordinate invariant point, a quadratic curve fitting is performed on the centroid 80 of the right plate cross section, the third coordinate invariant point and the fourth coordinate invariant point to obtain the expression of the right plate cross section; the expression of the right plate cross section is x2=a4y 2 +T4'; wherein T4' is the current abscissa of the centroid 80 of the right plate cross section. It can be understood by those skilled in the art that the ordinate of the centroid 80 of the right plate cross section is always zero;

[0091] According to the top plate section expression, the bottom plate section expression, the left plate section expression and the right plate section expression, the longitudinal strain at the centroid 50 of the top plate section and the longitudinal strain at the centroid of the bottom plate section, the axial force balance equation and the moment balance equation of the monitoring ring section are established;

[0092] The bending moment on the monitoring ring section is determined based on the axial force balance equation and moment balance equation on the monitoring ring section.

[0093] In this embodiment, since the thickness of the top plate 1 is different from that of the bottom plate 2, and the thickness of the top plate 1 is greater than that of the bottom plate 2, the centroid of the monitoring ring cross section in this embodiment is located above the centroid of the outer contour of the monitoring ring cross section. Those skilled in the art can understand that the bending moment acting on the monitoring ring cross section acts on the centroid of the monitoring ring cross section.

[0094] Since the left plate section and the right plate section are symmetrical about the Y axis, the left half and the right half of the top plate 1 are symmetrical about the Y axis, and the left half and the right half of the bottom plate 2 are symmetrical about the Y axis, the abscissa of the centroid of the monitoring ring section is 0, and the ordinate calculation formula of the centroid of the monitoring ring section is:

[0095]

[0096] Where d is the ordinate of the centroid of the monitoring ring cross section, i = 1, 2, 3, A s1 is the cross-sectional area of ​​the top plate, A s2 is the cross-sectional area of ​​the left plate and the cross-sectional area of ​​the right plate (the cross-sectional area of ​​the left plate is equal to the cross-sectional area of ​​the right plate), A s3 is the cross-sectional area of ​​the bottom plate; d1 is the centroid ordinate of the top plate 1, d2 is the centroid ordinate of the left plate 4 and the right plate 3, d3 is the centroid ordinate of the bottom plate 2, and the calculation formula of di is as follows:

[0097]

[0098] Optionally, an axial force balance equation of the pipe segment annular section is established, including:

[0099] Perform axial force balance analysis on the monitoring ring section (axial direction of the monitoring pipe section) to obtain the force balance equation of the monitoring ring section;

[0100] The force balance equation of the monitoring ring section is:

[0101]

[0102] Where N is the axial force at the monitoring ring section, E c is the elastic modulus of concrete; -T0 is the initial abscissa of the centroid of the left plate 4; T0 is the initial abscissa of the centroid of the right plate 3; C1 is the ordinate of the first and fourth coordinate invariant points; -C1 is the ordinate of the second and third coordinate invariant points.

[0103] The moment balance equation for the pipe section ring section includes:

[0104] Take the moment of the initial position point 50 of the top plate cross section centroid to establish the moment balance equation of the monitoring ring cross section;

[0105] The moment balance equation of the monitoring ring section is:

[0106]

[0107] Where M is the moment of the monitoring ring cross section.

[0108] Furthermore, those skilled in the art can understand that the calculation formula of the cross-sectional rotation angle θ can be obtained as follows:

[0109]

[0110] Here, θ is the angle between the ring cross section determined by the first fixing point 90 and the third fixing point 110 and the ring cross section determined by the second fixing point 100 and the fourth fixing point 120 .

[0111] The equivalent continuous beam rotation angle formula is:

[0112]

[0113] The equivalent bending stiffness (EI) can be obtained by combining eq expression:

[0114]

[0115] Among them, (EI) eq is the equivalent bending stiffness of the continuous beam; M is the bending moment of the monitoring ring section.

[0116] Optionally, the method for dynamically identifying the longitudinal bending stiffness of the prefabricated station provided in this embodiment further includes: obtaining the effective value of the current longitudinal bending stiffness of the pipe section according to the current longitudinal equivalent bending stiffness and the initial longitudinal bending stiffness of the pipe section;

[0117] The current effective longitudinal bending stiffness of the pipe section is:

[0118]

[0119] This embodiment also provides a system for dynamically identifying the longitudinal bending stiffness of a prefabricated station, which uses the above-mentioned method for dynamically identifying the longitudinal bending stiffness of a prefabricated station to dynamically monitor the longitudinal bending stiffness of the prefabricated station.

[0120] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for dynamically identifying the longitudinal bending stiffness of an assembled station, wherein the assembled station comprises a plurality of pipe sections spliced ​​in sequence, the pipe sections comprising a top plate (1) and a bottom plate (2) arranged in a vertically opposite manner, and a left plate (4) and a right plate (3) arranged in a horizontally opposite manner, characterized in that: include: Select a monitoring pipe section in the prefabricated station, and select a monitoring ring section in the monitoring pipe section. The monitoring ring section is a section in the monitoring pipe section that is perpendicular to the axis of the monitoring pipe section. Monitor the radial deformation of the monitoring ring cross section, and monitor the longitudinal strain of the monitoring pipe section at the monitoring ring cross section, and determine the bending moment of the monitoring ring cross section according to the radial deformation of the monitoring ring cross section and the longitudinal strain of the monitoring pipe section at the monitoring ring cross section; According to the calculation formula of equivalent bending stiffness and the bending moment of the monitoring ring section, the equivalent bending stiffness at the monitoring ring section is determined, and the equivalent bending stiffness at the monitoring ring section is used as the longitudinal bending stiffness of the prefabricated station; The monitoring ring cross section includes the top plate cross section, the bottom plate cross section, the left plate cross section and the right plate cross section; Monitor the radial deformation of the monitoring ring section, including: Selecting a first monitoring point (10) on the inner contour of the bottom plate cross section, selecting a second monitoring point (20) on the inner contour of the top plate cross section, selecting a third monitoring point (30) on the inner contour of the left plate cross section, and selecting a fourth monitoring point (40) on the inner contour of the right plate cross section, wherein the first monitoring point (10) is located at the center of the inner contour of the top plate cross section in the length direction, the second monitoring point (20) is located at the center of the inner contour of the bottom plate cross section in the length direction, the third monitoring point (30) is located at the center of the inner contour of the left plate cross section in the length direction, and the fourth monitoring point (40) is located at the center of the inner contour of the right plate cross section in the length direction; respectively monitoring the radial displacement of a first monitoring point (10), a second monitoring point (20), a third monitoring point (30) and a fourth monitoring point (40) along the monitoring pipe section; Monitor the longitudinal strain at the monitoring ring section, including: The longitudinal strains of the top plate (1) and the bottom plate (2) are respectively monitored by a strain monitoring device; The longitudinal strains of the top plate (1) and the bottom plate (2) are respectively monitored by a strain monitoring device, including: Using a first crack meter to monitor the distance between a first fixed point (90) and a second fixed point (100) on the inner contour of the monitoring pipe section, the first fixed point (90) and the second fixed point (100) are arranged at intervals along the axial direction of the monitoring pipe section, and a line connecting the first fixed point (90) and the second fixed point (100) on the inner contour of the monitoring pipe section passes through the first monitoring point (10); using a second crack meter to monitor the distance between a third fixed point (110) and a fourth fixed point (120) on the inner contour of the monitoring pipe section, the third fixed point (110) and the fourth fixed point (120) are arranged at intervals along the axial direction of the monitoring pipe section, and a line connecting the third fixed point (110) and the fourth fixed point (120) on the inner contour of the monitoring pipe section passes through the second monitoring point (20); Determine the longitudinal strain at the centroid (50) of the cross section of the top plate according to the change in distance between the first fixed point (90) and the second fixed point (100), and determine the longitudinal strain at the centroid (60) of the cross section of the bottom plate according to the change in distance between the third fixed point (110) and the fourth fixed point (120), wherein the centroid (50) of the cross section of the top plate and the centroid (60) of the cross section of the bottom plate are both located on a straight line determined by the first monitoring point (10) and the second monitoring point (20); The calculation formula of equivalent bending stiffness is: Among them, (EI) eq is the equivalent bending stiffness of the continuous beam; M is the bending moment of the monitoring ring section; ε c1 is the longitudinal strain at the centroid (60) of the bottom plate section; ε c2 is the longitudinal strain at the centroid (50) of the top plate cross section; T1 is the distance between the centroid (50) of the top plate cross section and the origin of the coordinate system, the centroid (50) of the top plate cross section is located on the straight line where the first monitoring point (10) and the second monitoring point (20) are located, and is located at the midpoint of the thickness direction of the top plate (1); T2 is the distance between the centroid (60) of the bottom plate cross section and the origin of the coordinate system, the centroid (60) of the bottom plate cross section is located on the straight line where the first monitoring point (10) and the second monitoring point (20) are located, and is located at the midpoint of the thickness direction of the bottom plate (2); t1′ is the distance between the centroid (50) of the top plate cross section and the first monitoring point (10); and t2′ is the distance between the centroid (60) of the bottom plate cross section and the second monitoring point (20).

2. The method for dynamic identification of longitudinal bending stiffness of prefabricated station according to claim 1 is characterized in that: The calculation formula for the longitudinal strain at the centroid (60) of the bottom plate section is: Wherein, δ1 is the current distance between the first fixed point (90) and the second fixed point (100); δ 10 is the initial distance between the first fixed point (90) and the second fixed point (100); The longitudinal strain calculation formula at the centroid (50) of the top plate section is: Wherein, δ2 is the current distance between the third fixed point (110) and the fourth fixed point (120); δ 20 is the initial distance between the third fixed point (110) and the fourth fixed point (120).

3. The method for dynamic identification of longitudinal bending stiffness of prefabricated station according to claim 2 is characterized in that: After selecting the monitoring ring section in the monitoring pipe section, it also includes: Selecting a first coordinate invariant point, a second coordinate invariant point, a third coordinate invariant point and a fourth coordinate invariant point on the cross section of the monitoring ring; A coordinate system is established with the centroid of the outer contour of the monitoring ring cross section as the origin, the Y axis of the coordinate system passes through the first monitoring point (10) and the second monitoring point (20), and the X axis of the coordinate system passes through the third monitoring point (30) and the fourth monitoring point (40); The coordinates of the first coordinate invariant point, the second coordinate invariant point, the third coordinate invariant point and the fourth coordinate invariant point on the coordinate system are determined.

4. The method for dynamic identification of longitudinal bending stiffness of prefabricated station according to claim 3 is characterized in that: The first coordinate invariant point is located at the joint of the top plate (1) and the left plate (4), and is located at the center of the top plate (1) in the thickness direction and the center of the left plate (4) in the thickness direction; the second coordinate invariant point is located at the joint of the left plate (4) and the bottom plate (2), and is located at the center of the left plate (4) in the thickness direction and the center of the bottom plate (2) in the thickness direction; the third coordinate invariant point is located at the joint of the bottom plate (2) and the right plate (3), and is located at the center of the bottom plate (2) in the thickness direction and the center of the right plate (3) in the thickness direction; the fourth coordinate invariant point is located at the joint of the right plate (3) and the top plate (1), and is located at the center of the right plate (3) in the thickness direction and the center of the top plate (1) in the thickness direction.

5. The method for dynamic identification of longitudinal bending stiffness of prefabricated station according to claim 3 is characterized in that: The bending moment of the monitoring ring section is determined according to the radial deformation of the monitoring ring section and the longitudinal strain of the monitoring pipe section at the monitoring ring section, including: According to the displacement of the first monitoring point (10), the second monitoring point (20), the third monitoring point (30) and the fourth monitoring point (40) along the radial direction of the monitoring pipe section, the current coordinates of the bottom plate cross section centroid (60), the top plate cross section centroid (50), the left plate cross section centroid (70) and the right plate cross section centroid (80) on the coordinate system are determined respectively; According to the current coordinates of the centroid (50) of the top plate cross section, the coordinates of the first coordinate invariant point and the coordinates of the fourth coordinate invariant point, a quadratic curve fitting is performed on the centroid (50) of the top plate cross section, the first coordinate invariant point and the fourth coordinate invariant point to obtain a top plate cross section expression; According to the current coordinates of the centroid (60) of the bottom plate cross section, the coordinates of the second coordinate invariant point and the coordinates of the third coordinate invariant point, a quadratic curve fitting is performed on the centroid (60) of the bottom plate cross section, the second coordinate invariant point and the third coordinate invariant point to obtain a bottom plate cross section expression; According to the current coordinates of the centroid (70) of the left plate cross section, the coordinates of the first coordinate invariant point and the coordinates of the second coordinate invariant point, a quadratic curve fitting is performed on the centroid (70) of the left plate cross section, the first coordinate invariant point and the second coordinate invariant point to obtain an expression of the left plate cross section; According to the current coordinates of the centroid (80) of the right plate cross section, the coordinates of the third coordinate invariant point and the coordinates of the fourth coordinate invariant point, a quadratic curve fitting is performed on the centroid (80) of the right plate cross section, the third coordinate invariant point and the fourth coordinate invariant point to obtain an expression of the right plate cross section; According to the top plate section expression, the bottom plate section expression, the left plate section expression and the right plate section expression, the longitudinal strain at the centroid (50) of the top plate section and the longitudinal strain at the centroid of the bottom plate section, the axial force balance equation and the moment balance equation of the monitoring ring section are established; The bending moment on the monitoring ring section is determined based on the axial force balance equation and moment balance equation on the monitoring ring section.

6. A dynamic identification system for longitudinal bending stiffness of an assembled station, characterized in that: The method for dynamic identification of longitudinal bending stiffness of an assembled station as described in any one of claims 1 to 5 is used to dynamically monitor the longitudinal bending stiffness of an assembled station.

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