Arch dam global horizontal displacement monitoring method

Abstract

The invention discloses a global horizontal displacement monitoring method for an arch dam. The global horizontal displacement monitoring method comprises the step of calculating global horizontal displacement of the arch dam through arch end vector displacement obtained through an arch ring of the arch dam and linear displacement of strain of any point of the arch ring of the arch dam. The linear displacement of any point is calculated through the strain distribution of the full length of the arch ring of the arch dam; arranging inverted pendants at two ends of the arch dam arch ring to obtain arch end vector displacement; the position of any point after deformation is obtained according to the fact that the macroscopic shape of the arch dam is unchanged and continuous, vector displacement can be obtained and further decomposed into radial displacement and tangential displacement, and then monitoring of the global horizontal displacement of the arch dam is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of safety monitoring of water conservancy and hydropower projects, and particularly relates to a method for monitoring horizontal displacement of an arch dam. BACKGROUND

[0002] In the safety monitoring of a concrete arch dam, the diversity law of horizontal displacement reflects the actual stress state of the arch dam, and accurate mastery of these change laws is the key to discovering abnormal deformation and preventing dam collapse accidents. The horizontal displacement data can decompose temperature, water level and other influencing factors to reveal the real working state of the arch dam.

[0003] Due to the arc shape of the arch dam in the plane, the quasi-straight line method commonly used for straight-line dams is not applicable to arch dams. The methods suitable for monitoring the horizontal displacement of arch dams mainly include surface deformation monitoring and the vertical line method.

[0004] Surface deformation monitoring mainly sets multiple measuring points on the dam top or behind the dam, such as the arch crown, 1 / 4 arch and 3 / 4 arch, and uses the intersection method to monitor the horizontal displacement. The intersection method observation has the following characteristics: ① The intersection method needs to arrange multiple working base points away from the deformation body, and the intersection angle needs to be between 30°-150°, preferably 90°-109°, otherwise the error will increase; ② The height difference between the working base point and the measuring point cannot be too large. For the case where the height difference of the measuring point is distributed in a large range, the working base point needs to be set in layers; ③ The geodetic method needs to observe multiple measuring returns to eliminate errors, which takes a long time to observe; the weather conditions are high, and rain, snow, fog and sun cannot be observed, which cannot achieve real-time monitoring; ④ The cost of automation is high, and the cost of a single station is about 1 million yuan. The intersection method needs to set at least two stations, with a cost of more than 2 million yuan; ⑤ The intersection method can only set representative points on the arch dam for observation, and cannot achieve global observation.

[0005] The vertical line method mainly sets positive and negative vertical lines on the section of the arch crown, 1 / 4 arch and 3 / 4 arch for observation, and calculates the horizontal displacement of the arch dam by superposition. Like surface deformation monitoring, the vertical line method can only select representative sections for observation, and cannot achieve global observation. In addition, the vertical line method needs to drill holes to install the vertical line, which requires high drilling and has high cost. The unit price of each meter is about 2500 yuan. Taking a 100m arch dam as an example, the negative vertical line is calculated at 40m deep into the bedrock, and three positive and negative vertical lines are set. The drilling cost is 140*3*2500=105 million yuan.

[0006] Through the analysis of surface deformation monitoring and the vertical line method, the two methods for monitoring the horizontal displacement of the arch dam have high cost, and can only achieve point monitoring, and cannot achieve global monitoring.

[0007] The patent application file with the publication number CN105890537A discloses a distributed optical fiber sensing technical solution and system for high arch dam deformation monitoring. In view of the characteristics and difficulties of double-curvature arch dams, two unique curved optical fiber packaging structures, i.e., a weak curved beam and a micro-bent beam type optical fiber monitoring plate, are provided. A convenient and practical layout and installation mode is provided in the gallery, shaft and adit of the arch dam and dam foundation, so as to realize multi-dimensional and large-range online telemetry of the internal deformation of the arch dam-dam foundation-dam shoulder (radial-tangential horizontal displacement, vertical displacement). The file mainly discloses the installation content of the optical fiber sensing technology, but does not solve the technical problem of calculating the global horizontal displacement of the arch dam. SUMMARY

[0008] To solve the above technical problems, the present application provides a global horizontal displacement monitoring method for an arch dam.

[0009] The present application is realized by the following technical solutions.

[0010] The present application provides a global horizontal displacement monitoring method for an arch dam, which comprises the process of obtaining the arch end vector displacement and the linear displacement of the strain of any point of the arch ring of the arch dam to calculate the global horizontal displacement of the arch dam.

[0011] Preferably, the arch ring is provided with an arch ring notch, the strain optical cable is laid in the arch ring notch, and the inverted perpendicular is arranged at both ends of the arch ring and is perpendicular to the arch ring.

[0012] A global horizontal displacement monitoring method for an arch dam comprises the following steps:

[0013] S1: An arch ring notch is arranged on the arch ring of the arch dam where the horizontal displacement needs to be observed, and a strain optical cable is laid in the arch ring notch;

[0014] S2: Inverted perpendiculars are arranged at both ends of the arch ring, the inverted perpendiculars at both ends are respectively set as point A and point B, and the displacements of points A and B are monitored;

[0015] S3: An arbitrary point C of the arch ring where the horizontal displacement needs to be monitored is set, the deformation amount of the arc length from point A to point C and the arc length from point B to point C is measured, and the combined displacement of point C is measured;

[0016] S4: The radial displacement and the tangential displacement of the arch ring are calculated through the combined displacement of point C, and the global horizontal displacement of the arch dam is obtained.

[0017] Preferably, the arc length from point A to point C is L1, and the deformation amount calculation formula of L1 is:

[0018]

[0019] The arc length from point B to point C is L2, and the deformation amount calculation formula of L2 is:

[0020]

[0021] In the formula: ΔL1 is the horizontal length variation amount at the structure length L1, ΔL2 is the horizontal length variation amount at the structure length L2, and ε(L) is the strain measurement value of the L section.

[0022] Preferably, the displacement deformation of the points A and B respectively obtains the points A' and B', the arc length of A'C' is L1+ΔL1, and the arc length of B'C' is L2+ΔL2.

[0023] According to the geometric transformation method, the line segment with the arc length L1+ΔL1 is rotated around the point A', the line segment with the arc length L2+ΔL2 is rotated around the point B', and the intersection point of the line segment with the arc length L1+ΔL1 and the line segment with the arc length L2+ΔL2 is the deformed C' point, and the vector length of CC' is the resultant displacement ΔC of the C point.

[0024] Preferably, in the calculation of the radial displacement and the tangential displacement of the arch dam arch ring, the angle θ between the C point and the dam axis of the arch dam arch ring is measured, the resultant displacement ΔC is decomposed into the radial displacement and the tangential displacement of the arch dam arch ring, and the radial displacement calculation formula is:

[0025] ΔCj=ΔC*sinθ

[0026] The tangential displacement calculation formula is:

[0027] ΔCq=ΔC*cosθ

[0028] In the formula: ΔCj is the radial displacement of the C point, and ΔCq is the tangential displacement of the C point.

[0029] The beneficial effects of the present application are:

[0030] The present application realizes the linear displacement of any point through the strain distribution of the full length of the arch dam arch ring, the vector displacement of the arch end is obtained by setting the inverse vertical at both ends of the arch dam arch ring, the deformed position of any point is obtained according to the invariance and continuity of the macroscopic shape of the arch dam, the vector displacement is obtained, which is further decomposed into the radial displacement and the tangential displacement, and the monitoring of the global horizontal displacement of the arch dam is realized.

[0031] The present application can realize the global horizontal displacement monitoring of the arch dam horizontal arch ring by using the inverse vertical, the strain optical cable and the strain demodulator, breaks through the limitations of the traditional point monitoring, obtains the global deformation of the dam, improves the safety monitoring capability of the dam, and protects the safety of the life and property of the downstream people. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a structural schematic diagram of the present application;

[0033] Figure 2 is a calculation principle diagram of the present application;

[0034] Figure 3 is a schematic view of the arch dam arch ring;

[0035] In the figure: 1-arch dam arch ring, 2-arch ring groove, 3-strain optical cable, 4-inverted. DETAILED DESCRIPTION

[0036] The technical solutions of the present application are described further below, but the scope of protection is not limited to the description.

[0037] Embodiment:

[0038] As shown in the figure, the arch dam arch ring 1 is consolidated on the bedrock, and according to the bending structure deformation theory of Materials Mechanics, the arch dam arch ring 1 causes material strain under the action of load such as reservoir water pressure, temperature load, etc., thereby causing body deflection change, i.e. horizontal displacement occurs. Therefore, the monitoring of the horizontal displacement of the arch dam arch ring 1 can be realized by monitoring the strain. Figure 3 The distributed sensing optical fiber technology can continuously sample at intervals of 0.5m on a continuous structure, and the strain measurement accuracy of each measurement unit is 30με.

[0039] According to the bending structure deformation theory of Materials Mechanics, the deformation of a structure is the continuous integral of strain in the length direction, and the calculation formula is as follows:

[0040]

[0041]

[0042] In the formula: ΔL is the horizontal length change amount at the structure length L, ε i is the strain measurement value of the i-th section.

[0043] Based on the above theory, the implementation process of the present application is as follows:

[0044] As shown in the figure, a kind of arch dam global horizontal displacement monitoring method includes the process of obtaining arch end vector displacement and linear displacement of strain of any point of arch dam arch ring 1 to calculate arch dam global horizontal displacement by arch dam arch ring 1. Figure 1 、 2 As shown in the figure, a kind of arch dam global horizontal displacement monitoring method includes the process of obtaining arch end vector displacement and linear displacement of strain of any point of arch dam arch ring 1 to calculate arch dam global horizontal displacement by arch dam arch ring 1.

[0045] The arch ring groove 2 is arranged on the arch dam arch ring 1, the strain optical cable 3 is laid in the arch ring groove 2, and the inverted 4 is arranged at both ends of the arch dam arch ring 1, and the inverted 4 is perpendicular to the arch dam arch ring 1.

[0046] A kind of arch dam global horizontal displacement monitoring method, comprising the following steps:

[0047] ​S1: setting an arch groove 2 on the arch ring 1 of the arch dam which needs to observe the horizontal displacement, and laying a strain cable 3 in the arch groove 2, the arch groove 2 and the strain cable 3 are well coupled, the deformation is consistent, the deformation of the strain cable 3 can represent the deformation of the arch ring 1 of the arch dam, and the strain of any point of the strain cable 3 is obtained through a strain demodulator;

[0048] S2: setting a reverse vertical 4 at each end of the arch ring 1 of the arch dam, the reverse vertical 4 at each end is respectively set as point A and point B, monitoring the displacement of the points A and B, observing the horizontal displacement of the arch end of the arch ring 1 under the action of load, and providing a reference for strain integration;

[0049] S3: setting an arbitrary point C on the arch ring 1 of the arch dam which needs to monitor the horizontal displacement, measuring the deformation amount of the arc length from the point A to the point C and the arc length from the point B to the point C, and measuring the combined displacement of the point C;

[0050] S4: calculating the radial displacement and the tangential displacement of the arch ring 1 of the arch dam through the combined displacement of the point C, and obtaining the horizontal displacement condition of the whole arch dam.

[0051] The arc length from the point A to the point C is L1, and the deformation amount calculation formula of L1 is:

[0052]

[0053] The arc length from the point B to the point C is L2, and the deformation amount calculation formula of L2 is:

[0054]

[0055] In the formula, ΔL1 is the horizontal length change amount of the structure L1, ΔL2 is the horizontal length change amount of the structure L2, and ε(L) is the strain measurement value of L.

[0056] After monitoring the displacement of the points A and B, the points A' and B' are obtained, the arc length of A'C' is L1+ΔL1, and the arc length of B'C' is L2+ΔL2;

[0057] According to the geometric transformation method, the line segment of the arc length L1-ΔL1 rotates around the point A', the line segment of the arc length L2+ΔL2 rotates around the point B', and the intersection point of the line segment of the arc length L1+ΔL1 and the line segment of the arc length L2+ΔL2 is the deformed point C', and the vector length of CC' is the combined displacement ΔC of the point C.

[0058] In the calculation of the radial displacement and the tangential displacement of the arch ring 1 of the arch dam, the angle θ between the point C and the dam axis of the arch ring 1 of the arch dam is measured, the combined displacement ΔC is decomposed into the radial displacement and the tangential displacement of the arch ring 1 of the arch dam, and the radial displacement calculation formula is:

[0059] ΔCj=ΔC*sinθ

[0060] The tangential displacement calculation formula is:

[0061] ΔCq=ΔC*cosθ

[0062] In the formula, ΔCj is the radial displacement of the C point, and ΔCq is the tangential displacement of the C point.

[0063] The principle of the above calculation is as shown in Figure 3 In the calculation formula of the application, all arc length units are m, and all displacement units are mm. Full-automatic processing can be realized by using a computer. The horizontal displacement monitoring of any point of the arch dam arch ring 1 can be realized by the above method, which is an advantage that cannot be matched by point monitoring. Moreover, the method has a relatively low cost. Taking a medium-sized dam project as an example, assuming that the arc length of the dam top is 200 m, the total cost of the strain demodulator and the strain optical cable 3 is within 200,000 yuan, which is obviously superior to the traditional surface deformation monitoring and the vertical line method.

Claims

1. A method for monitoring global horizontal displacement of an arch dam, characterized by: The invention includes a process of calculating the global horizontal displacement of the arch dam by obtaining the arch end vector displacement of the arch dam arch ring (1) and the linear displacement of the strain at any point of the arch dam arch ring (1).

2. The method for monitoring global horizontal displacement of an arch dam according to claim 1, wherein: An arch ring groove (2) is provided on the arch ring (1), a strain optical cable (3) is laid in the arch ring groove (2), and inverted hooks (4) are provided at both ends of the arch ring (1), and the inverted hooks (4) are perpendicular to the arch ring (1).

3. A method for monitoring global horizontal displacement of an arch dam according to claim 1 or 2, characterized in that: The following steps are involved: S1: An arch ring groove (2) is provided on the arch ring (1) of the arch dam where horizontal displacement needs to be observed, and a strain optical cable (3) is laid in the arch ring groove (2); S2: Set up inverted pendants (4) at both ends of the arch ring (1) of the arch dam, and set the inverted pendants (4) at both ends as points A and B respectively, and monitor the displacement of points A and B; S3: Set any point on the arch ring (1) of the arch dam where horizontal displacement needs to be monitored as point C, measure the deformation of the arc length from point A to point C and from point B to point C, and measure the total displacement of point C; S4: Calculate the radial displacement and tangential displacement of the arch ring (1) of the arch dam through the combined displacement of point C, and obtain the overall horizontal displacement of the arch dam.

4. The method for monitoring global horizontal displacement of an arch dam according to claim 3, wherein: The arc length from point A to point C is measured as L1, and the deformation calculation formula of L1 is: The arc length from point B to point C is measured as L2. The deformation calculation formula of L2 is: Where: ΔL1 is the horizontal length change at the structure length L1, ΔL2 is the horizontal length change at the structure length L2, and ε(L) is the strain measurement value of the L segment.

5. The method for monitoring global horizontal displacement of an arch dam according to claim 4, characterized in that: After monitoring the displacement deformation of point A and point B, the points A' and B' are obtained respectively. The arc length of A'C' is L1+ΔL1, and the arc length of B'C' is L2+ΔL2; According to the geometric transformation method, the line segment with arc length L1+ΔL1 rotates around point A', and the line segment with arc length L2+ΔL2 rotates around point B'. The intersection of the line segment with arc length L1+ΔL1 and the line segment with arc length L2+ΔL2 is the deformed point C', and the vector length CC' is the total displacement ΔC of point C.

6. The method for monitoring global horizontal displacement of an arch dam according to claim 5, characterized in that: In calculating the radial displacement and tangential displacement of the arch ring (1), the angle θ between point C and the dam axis of the arch ring (1) is measured, and the total displacement ΔC is decomposed into the radial displacement and tangential displacement of the arch ring (1). The radial displacement calculation formula is: ΔCj=ΔC*sinθ The calculation formula for tangential displacement is: ΔCq=ΔC*cosθ Where: ΔCj is the radial displacement of point C, and ΔCq is the tangential displacement of point C.

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