CN214583759U - Distributed monitoring structure for anchoring state of prestressed tendon group - Google Patents
Distributed monitoring structure for anchoring state of prestressed tendon group Download PDFInfo
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- CN214583759U CN214583759U CN202023065556.9U CN202023065556U CN214583759U CN 214583759 U CN214583759 U CN 214583759U CN 202023065556 U CN202023065556 U CN 202023065556U CN 214583759 U CN214583759 U CN 214583759U
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Abstract
The application relates to the field of pavement engineering, in particular to a distributed monitoring structure for an anchoring state of a prestressed tendon group. The application provides a prestressing tendons crowd anchor state distributed monitoring structure, including shop front body and distributed sensing optic fibre, the shop front body includes concrete structure and cross distribution's prestressing tendons crowd, at least part prestressing tendons in the prestressing tendons crowd is including revealing in the portion that exposes of concrete structure, at least part expose and to be equipped with anchor assembly and the pressure-bearing spare of mutually supporting in the portion, including the optic fibre holding tank on the pressure-bearing spare, distributed sensing optic fibre still includes the packaging part including induction zone optic fibre and buffer zone optic fibre, induction zone optic fibre passes through the packaging part and encapsulates in the optic fibre holding tank. The distributed monitoring structure for the anchoring state of the prestressed tendon group utilizes the advantages of low power consumption and long-distance transmission of the distributed sensing optical fiber, and meets the large-range and distributed monitoring requirements for the anchoring state of the prestressed tendon group.
Description
Technical Field
The utility model relates to a shop front engineering field especially relates to a prestressing tendons crowd anchoring state distributed monitoring structure.
Background
The oblique prestressed pavement has the advantages that the prestress is generated in the longitudinal direction and the transverse direction of the pavement by arranging the double-oblique-direction crossed prestressed tendons, the advantages of a prestressed structure are exerted, the defects of the traditional longitudinal prestressed structure in design and construction are overcome, seam diseases can be well avoided, the oblique prestressed pavement has the advantages of being long in plate length, few in seam, durable, safe and the like, and has a good popularization prospect.
The prestressed ribs in the oblique prestressed pavement are large in quantity and wide in distribution, exist in a rib group form and play a prestressed role; and because the anchoring form of the oblique prestressed pavement is special, the prestress action is mainly transferred through the anchorage device, so that the bearing capacity of the pavement structure is closely related to the anchoring state of the prestressed tendon group.
However, the main problems faced by the existing diagonal pre-stressed deck structures are: under the influence of prestress loss, the anchoring force of each prestressed tendon is continuously attenuated, the anchoring state of a prestressed tendon group is continuously degraded, and the bearing capacity of a pavement structure is obviously influenced, so that the anchoring state of the oblique prestressed pavement is timely monitored, and the method has important significance for guaranteeing the service life of the pavement.
In order to solve the problems, a common method is to use a single-point sensor, such as a strain gauge, a dynamometer, a fiber grating and the like, to monitor the prestress loss, and the method has a structure with a small number of prestress ribs such as a prestressed beam and a longitudinal prestress pavement or with concentrated distribution, but for a prestress rib group with a large number and wide distribution, a large number of single-point sensors are required to be arranged in a large range if synchronous monitoring is required, and the single-point sensors are often independently networked, so that the complexity of a sensing line is easily caused, the field installation workload is increased, the later data transmission and analysis efficiency is also influenced, and the requirement of large-range and distributed monitoring of the anchoring state of the prestress rib group is difficult to meet.
SUMMERY OF THE UTILITY MODEL
In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a distributed monitoring structure and method for tendon group anchoring state, which is used to solve the problems in the prior art.
In order to realize above-mentioned purpose and other relevant purposes, the utility model provides a prestressing tendons crowd anchor state distributed monitoring structure, a serial communication port, including shop front body and distributed sensing optic fibre, the shop front body includes concrete structure and cross distribution's prestressing tendons crowd, at least part prestressing tendons in the prestressing tendons crowd is including exposing in the portion that exposes of concrete structure, at least part the cover is equipped with anchor assembly and the bearing part of mutually supporting in the portion that exposes, the bearing part is located between anchor assembly and the concrete structure, include the optic fibre holding tank on the bearing part, distributed sensing optic fibre still includes the packaging part including response section optic fibre and buffer segment optic fibre, response section optic fibre passes through the packaging part and encapsulates in the optic fibre holding tank, the buffer segment optic fibre is located between the response section optic fibre.
In some embodiments of the present invention, the distributed sensing fiber is a single mode fiber, the tensile strength of the distributed sensing fiber is greater than or equal to 30N, and the attenuation of the distributed sensing fiber is less than or equal to 0.22db/km (1550 MHz).
The utility model discloses in some embodiments, the length of the response section optic fibre on single bearing part is 4 ~ 8m, response section optic fibre adopts tight package optic fibre, the optic fibre winding diameter d of response section optic fibre2The following formula is satisfied:
ΔF≤0.01Fp；
wherein d ispTo make a preliminary responseNominal diameter of the tendon, E the modulus of elasticity of the bearing member, μ the Poisson's ratio of the bearing member, εminThe minimum frequency shift of the optical fiber analysis of the induction section is defined, delta F is the minimum identification precision of the prestressed tendon anchoring state monitoring, and FpFor the tension anchorage of the tendon, dp9 to 16mm, FpIs 60 to 400 kN.
In some embodiments of the invention, d2Is 0.6 to 0.9 mm.
The utility model discloses in some embodiments, the length of the buffer segment optic fibre between two bearing parts is 2 ~ 6m, the shape of laying of buffer segment optic fibre is the combination that the linearity was laid, the curve was laid, the annular was laid one or more, the buffer segment optic fibre adopts armor optic fibre.
The utility model discloses in some embodiments, all the cover is equipped with anchor assembly and the pressure-bearing piece of mutually supporting on the portion that exposes of each prestressing tendons, the pressure-bearing piece is the cavity cylinder, the external diameter of pressure-bearing piece is 5 ~ 10cm, the thickness h of pressure-bearing piece satisfies following formula:
wn≤h≤1.2wn；
wherein w is the width of the sensing section optical fiber, d2Is the winding diameter of the optical fiber, LminAnd n is the number of turns of spiral distribution for the minimum spatial resolution of the optical fiber analysis of the induction section.
In some embodiments of the present invention, h is 2-4 cm.
The utility model discloses in some embodiments, the bearing part includes the unanimous optic fibre holding tank of one or more extending direction and bearing part extending direction, and the number of optic fibre holding tank is 1 ~ 14 in single bearing part, the internal diameter d of optic fibre holding tank1The following formula is satisfied:
1.05dp≤d1≤1.4dp；
wherein d ispIs the nominal diameter of the tendon.
In bookIn some embodiments of the invention, d1Is 1.5-3 cm.
In some embodiments of the present invention, the optical fiber accommodating groove is distributed on a side surface of the pressure-bearing member, a depth of the optical fiber accommodating groove is 1-2 mm, and a width of the optical fiber accommodating groove is 1-2 mm;
the induction section optical fiber is spirally and uniformly distributed on the side surface of the pressure-bearing part, and the number of spirally distributed turns n meets the following formula:
wherein L isminMinimum spatial resolution for the fiber resolution of the sensing segment;
the packaging part is a flexible packaging part, and the packaging part and the pressure-bearing part are bonded through an adhesive.
The optical fiber frequency shift demodulation device is connected with the distributed sensing optical fiber signal and is selected from one of BOTDA, BOTDR and BOFDA.
Drawings
Fig. 1 shows that the utility model discloses well prestressing tendons crowd anchoring state distributed monitoring structure in distributed sensing optical fiber lay the schematic diagram.
Fig. 2 shows the schematic structural diagram of the pressure-bearing part and the sensing section optical fiber in the distributed monitoring structure for the anchoring state of the middle prestressed tendon group of the present invention.
Fig. 3 shows a schematic structural diagram of the distributed monitoring structure for the anchoring state of the tendon group according to the present invention.
Fig. 4 shows a schematic flow chart of the distributed monitoring method for the anchoring state of the tendon group in the present invention.
Fig. 5 is a schematic view showing the analysis process of the anchoring state of the tendon group according to the present invention.
Fig. 6 is a schematic diagram illustrating a calibration process of the standard functional relationship between the characteristic index of the sensing section optical fiber and the load state of the pressure-bearing member according to the present invention.
Fig. 7 is a schematic diagram of the frequency shift value corresponding to the pressure-bearing device in different loading states in embodiment 2 of the present invention.
Fig. 8 is a schematic diagram showing the relationship between the standard functions in embodiment 2 of the present invention.
Fig. 9 is a schematic view of data collected by the monitoring system in embodiment 3 of the present invention.
Fig. 10 is a schematic view illustrating the accuracy verification of the monitoring system in embodiment 3 of the present invention.
Description of the element reference numerals
1 paving body
11 concrete structure
12 prestressed tendon group
123 exposed part
2 pressure-bearing part
21 optical fiber accommodating groove
22 packaging part
3 anchoring element
4 distributed sensing optical fiber
41 induction section optical fiber
42 buffer segment optical fiber
5 optical fiber frequency shift demodulation equipment
Detailed Description
In order to make the objects, technical solutions and advantageous effects of the present invention more clear, the present invention will be further described in detail with reference to the following embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the disclosure of the present specification.
The utility model discloses the inventor provides a prestressing tendons crowd anchor attitude distributed monitoring structure and method through a large amount of practical studies, and above-mentioned monitoring structure and method can in time monitor the anchor state of slant prestressing force shop front, and effective guarantee shop front is in service life-span, has accomplished on this basis the utility model discloses a monitoring structure and method.
The utility model provides a distributed monitoring structure for the anchoring state of a prestressed tendon group, which comprises a pavement body 1 and a distributed sensing optical fiber 4, the pavement body 1 comprises a concrete structure 11 and prestressed tendon groups 12 distributed in a cross way, at least part of prestressed tendons in the prestressed tendon groups 12 comprises an exposed part 123 exposed out of the concrete structure 11, at least part of the exposed part 123 is sleeved with an anchoring part 3 and a pressure-bearing part 2 which are mutually matched, the pressure-bearing member 2 is positioned between the anchoring member 3 and the concrete structure 11, the pressure-bearing member 2 includes an optical fiber receiving groove 21, the distributed sensing optical fiber 4 includes a sensing segment optical fiber 41 and a buffer segment optical fiber 42, and further includes an enclosure 22, the sensing segment optical fiber 41 is packaged in the optical fiber containing groove 21 through the packaging member 22, and the buffer segment optical fiber 42 is located between the sensing segment optical fibers 41. In the monitoring structure, the bearing part 2 is located between the anchoring part 3 and the concrete structure 11, the bearing part 2, the anchoring part 3 and the concrete structure 11 are usually in close contact, after the prestressed tendon is tensioned, the anchoring part 3 limits retraction of the prestressed tendon, the pre-pressure is transmitted to the bearing part 2 through the anchoring part 3, the bearing part 2 bears the anchoring force of the prestressed tendon, the bearing part 2 usually has certain flexibility and can generate certain compression deformation under the anchoring effect to trigger frequency shift change of the sensing section optical fiber 41 arranged therein, and further through external equipment (such as an optical fiber frequency shift demodulation device 5 and the like) connected with the distributed sensing optical fiber 4, frequency shift data collected by the distributed sensing optical fiber 4 can be collected and analyzed, and the anchoring state of the inclined prestressed pavement is further monitored.
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring structure, shop front body 1 includes concrete structure 11 and cross distribution's prestressing tendons crowd 12 usually. Generally speaking, the tendons are usually arranged obliquely in the concrete structure 11 of the pavement, i.e. parallel to the road surface but at a certain angle (e.g. 20-45 °, 20-25 °, 25-30 °, 30-35 °, 35-40 °, or 40-45 °) to the overall extension direction of the pavement, and may generally include multiple groups (e.g. two groups) of tendons arranged crosswise to each other, and each group of tendons usually includes multiple tendons that are parallel to each other and have a suitable spacing distance (e.g. 50-70 cm, 50-55 cm, 55-60 cm, 60-65 cm, or 65-70 cm).
The utility model provides an among the distributed monitoring structure of prestressing tendons crowd anchor state, the distributed sensing optical fiber 4 that uses (for example, response section optic fibre 41, buffer segment optic fibre 42 etc.) is single mode fiber usually. In order to avoid damage during installation and use, the distributed sensing optical fiber 4 usually has a certain tensile strength, for example, the tensile strength of the distributed sensing optical fiber 4 is usually ≧ 30N. In order to ensure the accuracy of the optical fiber frequency shift demodulation, the distributed sensing optical fiber 4 usually has suitable attenuation parameters, for example, the attenuation of the distributed sensing optical fiber 4 is usually less than or equal to 0.22db/km (1550 MHz). The distributed sensing optical fiber 4 generally comprises a sensing segment optical fiber 41 and a buffer segment optical fiber 42, and the total length thereof can be adjusted according to the length of the pavement body 1 and the number of matched bearing members 2, for example, the total length of the distributed sensing optical fiber 4 is generally more than or equal to 1 km.
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring structure, can include induction section optic fibre 41 among the distributed sensing optic fibre 4. The sensing section optical fiber 41 is usually a tightly-packed optical fiber, i.e. an optical fiber with a tightly-sleeved secondary coating structure, so as to facilitate the distribution of the sensing section optical fiber 41 on the surface of the pressure bearing member 2. As described above, the sensing section optical fiber 41 is mainly distributed on the pressure bearing member 2 to sense the deformation of the pressure bearing member 2 and cause the frequency shift change itself. The sensing segment optical fiber 41 has to have a proper length and shape so as to be capable of being matched with the pressure bearing member 2 to accurately reflect the compression deformation of the pressure bearing member 2, thereby accurately monitoring the anchoring state of the tendon group. For example, for a single pressure-bearing member 2, the length of the sensing section optical fiber 41 distributed thereon may be 4-8 m, 4-5 m, 5-6 m, 6-7 m or 7-8 m. As another example, the fiber winding diameter d of the sensing section fiber 412(since the optical fiber is wound in the groove on the side surface of the pressure-bearing part, the winding diameter of the optical fiber can be directly regarded as the diameter of the pressure-bearing part 2) can be determined according to the material characteristics of the pressure-bearing part body, and the following formula can be specifically satisfied:
ΔF≤0.01Fpwherein d ispThe nominal diameter of the tendon (corresponding generally to the exposed portion 123), E the modulus of elasticity of the pressure-bearing member 2, μ the Poisson's ratio of the pressure-bearing member 2, εminThe minimum frequency shift analyzed by the sensing section optical fiber 41, delta F is the minimum identification precision of the prestressed tendon anchoring state monitoring, FpThe stretching and anchoring force of the prestressed tendon is adopted. dpCan be 9-22 mm, 9-16 mm, 9-10 mm, 10-12 mm, 12-14 mm, 14-16 mm, 16-18 mm, 18-20 mm, 20-22 mm, 9.5mm, 12.7mm, 15.2mm, 17.8mm, or 21.6 mm. FpCan be 60 to 400kN, 66.9 to 76.2kN, 120.4 to 137.2kN, 155.4 to 194.6kN, 231.8 to 250.8kN, or 356.3 to 376.2 kN. d2Specifically, the thickness may be 0.6 to 0.9mm, 0.6 to 0.7mm, 0.7 to 0.8mm, or 0.8 to 0.9 mm.
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring structure, can include buffer segment optic fibre 42 among the distributed sensing optic fibre 4. The buffer section optical fiber 42 can be commonly armored by adding a metal protection layer on the outermost surface of the optical fiber to prevent the inner utility layer from being damaged. Unlike the sensing section optical fiber 41, the buffer section optical fiber 42 is generally used to connect the sensing section optical fiber 41 on each bearing member 2. The frequency shift of the buffer segment optical fiber 42 is usually not significantly related to the compression state of the pressure bearing member 2, but is related to the ambient temperature. Therefore, the measurement results of the adjacent induction section optical fibers 41 can be separated on the frequency shift value-distributed optical fiber axial distance, and subsequent data analysis and prestressed tendon group anchoring state monitoring are facilitated. The buffer segment optical fiber 42 generally needs to have a suitable length and shape to match the layout and tendon parameters. For example, the length L of the buffer segment optical fiber 42 can be determined according to the pre-stressed tendon layout spacing and the optical fiber demodulation parametershSpecifically, the following formula can be satisfied: max (L)j,Lmin)≤Lh≤1.5LminWherein L isjFor laying space, L, for prestressed tendonsminMinimum spatial resolution for sensing section fiber resolution. The length of the buffer section optical fiber 42 between the two pressure-bearing pieces 2 can be specifically 2-6 m, 2-3 m, 3-4 m, 4-5 m or 5-6 m. As another example, the arrangement shape of the buffer segment optical fibers 42 may be a linear arrangement, a curved arrangement, or a circular arrangementAnd the like. The length of the buffer segment optical fiber 42 may be generally different from the pre-stressed rib arrangement spacing (applicable to linear arrangement, curved arrangement, etc.), or may be significantly larger than the pre-stressed rib arrangement spacing (applicable to linear arrangement, curved arrangement, circular arrangement, etc.). When a curved layout is used, the radius of curvature r of the curved layout1The following formula can be satisfied: r is1≥0.5d2. When using a circular layout, the diameter d of the circular layout3The following formula can be satisfied: d2≤d3≤1.5d2Wherein d is2The diameter of the optical fiber winding of the induction section is measured.
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring structure, the distribution of the prestressing tendons in the distribution of pressure-bearing part 2 and prestressing tendons crowd 12 usually is matchd mutually. For example, in principle, each tendon may be generally provided with a pressure-bearing member 2. For another example, the tensioned end (e.g., the exposed portion 123) of each tendon may be sleeved with the anchor member 3 and the pressure-bearing member 2 that are engaged with each other. Both ends of the prestressed tendon generally need to be exposed, but the stretching end is longer (the length is generally 40-60 cm) for convenient stretching, the exposed length is generally longer, the end generally corresponds to the exposed part 123, the other end is generally called as a fixed end (the length is generally 10-15 cm), in pavement engineering, single-end (generally at the exposed part) stretching is generally more common, a detection device is generally arranged at the stretching end, and because the difference of the measurement results of the two ends of the same tendon is not too large, the stretching end can be located on the same side of the pavement body 1. Of course, the non-stretching end (i.e. the fixed end) of each tendon may also be provided with a detection device, i.e. both are sleeved with the anchor member 3 and the pressure-bearing member 2 which are mutually matched.
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring structure, pressure-bearing piece 2 is the cavity cylinder for having certain thickness and size usually to provide glossy surface in order to bear and encapsulate induction segment optic fibre 41. For example, the outer diameter of the pressure receiving member 2 may be 5 to 10cm, 5 to 6cm, 6 to 7cm, 7 to 8cm, 8 to 9cm, or 9 to 10 cm. For another example, the thickness h of the pressure receiving member 2 may be determined according to the winding diameter of the optical fiber, and may specifically satisfy the following formula：wn≤h≤1.2wn、
Wherein w is the width (usually 1-2 mm, 1-1.2 mm, 1.2-1.4 mm, 1.4-1.6 mm, 1.6-1.8 mm, or 1.8-2 mm) of the sensing segment optical fiber 41, d2For sensing the winding diameter, L, of the length of optical fiber 41minThe minimum spatial resolution (usually 0.2-2 m, 0.2-0.4 m, 0.4-0.6 m, 0.6-0.8 m, 0.8-1 m, 1-1.2 m, 1.2-1.4 m, 1.4-1.6 m, 1.6-1.8 m, or 1.8-2 m) for the analysis of the sensing section optical fiber 41, n is the number of turns of the spiral distribution. The h can be specifically 2-4 cm, 2-2.5 cm, 2.5-3 cm, 3-3.5 cm, or 3.5-4 cm. The cross section of the pressure-bearing member 2 may be generally a single-hole circular ring shape or a multi-hole circular shape, that is, the pressure-bearing member 2 may include one or more optical fiber receiving grooves 21 with a suitable size and extending in the same direction as the pressure-bearing member 2, so as to be used for receiving the exposed portion 123 of the tendon. For example, the number of the optical fiber accommodating grooves 21 in a single pressure-bearing member 2 may be 1 to 2, 2 to 4, 4 to 6, 6 to 8, 8 to 10, 10 to 12, or 12 to 14. As another example, the inner diameter d of the optical fiber accommodating groove 211The method can be determined according to the nominal diameter of the prestressed tendon, and can specifically satisfy the following formula: 1.05dp≤d1≤1.4dpWherein d ispIs the nominal diameter of the tendon (generally corresponding to its exposed portion 123), d1Preferably 1.5 to 3cm, 1.5 to 2cm, 2 to 2.5cm, or 2.5 to 3 cm. As mentioned above, the pressure-bearing member 2 generally needs to have suitable rigidity and flexibility to support the tendon anchoring force without breaking, and to deform enough to induce a suitable frequency shift in the sensing section optical fiber 41. For example, the material of the pressure bearing member 2 may be one or a combination of more of iron, aluminum, or an alloy thereof. For another example, the frequency shift of the pressure-bearing member 2 may be less than or equal to 0.08GHz, less than or equal to 0.02GHz, 0-0.04 GHz, 0.04-0.06 GHz, 0.06-0.08 GHz, which generally depends on the accuracy of the optical fiber frequency shift demodulation device 5 in acquiring and identifying the frequency shift.
The utility model provides an among the prestressed tendons crowd anchor state distributed monitoring structure, optic fibre holding tank 21 distributes in the side of pressure-bearing part 2, and the corresponding optic fibre holding tank 21 that is arranged in, and extending direction and optic fibre holding tank 21 assorted induction segment optic fibre 41 then also distributes in the side of pressure-bearing part 2. The size and distribution length of the fiber receiving groove 21 generally matches the size and length of the sensing segment fiber 41. For example, the width w of the fiber accommodating groove 21 can be determined according to the width of the sensing segment fiberoSpecifically, the following formula can be satisfied: w is less than or equal to woIs less than or equal to 2w, wherein w is the width of the sensing section optical fiber 41. Width w of optical fiber accommodating groove 21oSpecifically, the depth of the optical fiber accommodating groove 21 may be 1 to 2mm, 1 to 1.2mm, 1.2 to 1.4mm, 1.4 to 1.6mm, 1.6 to 1.8mm, or 1.8 to 2mm, and the depth of the optical fiber accommodating groove may be 1 to 2mm, 1 to 1.2mm, 1.2 to 1.4mm, 1.4 to 1.6mm, 1.6 to 1.8mm, or 1.8 to 2 mm. The sensing section optical fiber 41 is generally spirally and uniformly distributed on the side surface of the pressure bearing member 2 (the distribution direction is consistent with the thickness direction of the pressure bearing member 2), for example, the number of spirally distributed turns n can be determined according to the winding diameter of the optical fiber, and the following formula can be specifically satisfied:
wherein L isminThe minimum spatial resolution resolved for the sensing segment fiber 41. n is 20-30 turns, 20-25 turns, or 25-30 turns.
The utility model provides an among the distributed monitoring structure of prestressing tendons crowd anchor state, packaging part 22 is flexible packaging part usually, and packaging part 22 closely laminates in the surface (for example, the lateral wall) that the pressure-bearing part distributes and has optic fibre holding tank 21 usually, bonds through the binder between packaging part 22 and the pressure-bearing part 2. Those skilled in the art can select suitable encapsulating materials and adhesives to encapsulate the optical fibers described above. For example, the adhesive may be a combination of one or more of a silicone glue, 502 glue, hot melt glue, and the like. As another example, the flexible encapsulant material may be a combination of one or more of epoxy, polyvinyl chloride glue, and the like.
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring structure, can also include optic fibre frequency shift demodulation equipment 5, optic fibre frequency shift demodulation equipment 5 usually with 4 signal connection of distributed sensing optic fibre, for example, can be through conduction fiber connection, material, the model etc. of conduction optic fibre are basic and distributed sensing optic fibre 4, unanimous including induction zone optic fibre 41, buffer segment optic fibre 42 etc.. The optical fiber frequency shift demodulation device 5 is mainly used for collecting and analyzing frequency shift data collected by the distributed sensing optical fiber 4 and further monitoring the anchoring state of the oblique prestressed pavement. Suitable fiber-optic frequency-shift demodulating devices 5 should be known to those skilled in the art, for example, the fiber-optic frequency-shift demodulating device 5 may be one of BOTDA, BOTDR, BOFDA, and the like. The connection form of the fiber frequency shift demodulation device 5 and each section of the distributed sensing fiber 4 can be adjusted by those skilled in the art. For example, at least some of the sensing section fibers 41 and the buffer section fibers 42 may be connected in series, and one or more sensing section fibers 41 and one or more buffer section fibers 42 may be connected in series at the same time. For another example, a certain number of sensing segment optical fibers 41 and buffer segment optical fibers 42 may be connected in series to form one optical fiber unit, and a plurality of optical fiber units may be further connected in parallel to the optical fiber frequency shift demodulation device 5.
The utility model discloses the second aspect provides a prestressing tendons crowd anchor state distributed monitoring method, through the utility model discloses the prestressing tendons crowd anchor state distributed monitoring structure that the first aspect provided monitors the anchor state of prestressing tendons crowd. Generally, the anchoring state refers to the action state of the anchoring force of the tendon group, and usually reflects the change of the acting position, size, angle and the like of the anchoring force.
The utility model provides a prestressing tendons crowd anchor attitude distributed monitoring method can include:
1) providing distributed sensing optical fiber data of a pavement body to be detected;
2) providing the anchoring state of the prestressed tendon group according to the distributed sensing optical fiber data of the pavement body to be detected, which is provided in the step 1).
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring method, according to the distributed sensing optical fiber data of the shop front body that awaits measuring that step 1) provided, the method that provides the anchor state of prestressing tendons crowd specifically can include:
1) segmenting distributed sensing optical fiber (frequency shift) data to provide segmented optical fiber frequency shift data groups; the data segmentation mainly adopts window function segmentation, and the window function segmentation mainly can be based on the length of the sensing section optical fiber and the length of the buffer section optical fiber, for example, the window function and the length of the sensing section optical fiber and the length of the buffer section optical fiber can satisfy the following formulas:
Lg≤W1≤Lg+Lh
W2＝Lg+Lh-W1
wherein, W1As a function of window width, W2Is the window function spacing, LgFor sensing the length of the section fibre, LhIs the buffer segment optical fiber length;
2) extracting a characteristic index set of the optical fiber frequency shift data group according to the segmented optical fiber frequency shift data group provided in the step 1); the characteristic index set of the optical fiber frequency shift data group may be a set of characteristic indexes of sections corresponding to each sensing section of optical fiber in the optical fiber frequency shift data group, and the characteristic index corresponding to a sensing section of optical fiber in a single section may be a representative value of the frequency shift data of the section corresponding to the sensing section of optical fiber, for example, one or a combination of a maximum value, an average value, a 95 quantile value, and the like;
3) providing temperature correction values Δ ε for fiber frequency shift data setsT(ii) a The temperature correction value can be calculated by measuring the obtained real-time temperature, and specifically, the following formula can be satisfied:
ΔεT＝αT(T-T0)
wherein alpha isTIs the temperature sensitive coefficient of the sensing section optical fiber, T is the measured real-time temperature, T0Is the calibration temperature (i.e. the temperature at which the test is calibrated);
the temperature correction value can also be calculated by the frequency shift of the buffer section optical fiber, and the following formula can be satisfied:
wherein epsilonT1、εT2Respectively representing the characteristic indexes of the buffer section optical fiber adjacent to the front and the back of the induction section optical fiber;
4) based on the characteristic index set provided in step 2) and the temperature correction value delta epsilon provided in step 3)TProviding a corrected characteristic index set; for example, the set of characteristic indicators may be correlated with the temperature correction value Δ εTSumming to provide a revised set of feature indicators;
5) providing the anchoring state of the prestressed tendon group based on the corrected characteristic index set provided in the step 4).
The utility model provides an among the prestressing tendons crowd anchor state distributed monitoring method, generally speaking, can compare the distributed sensing optical fiber data of the shop front body that awaits measuring (for example, the characteristic index set of the correction as above that provides) and the standard function relation of the response section optic fibre characteristic index of demarcating in advance and pressure-bearing member loaded state to the anchor state that provides prestressing tendons crowd. The standard function of the characteristic index of the optical fiber of the induction section and the loading state of the pressure-bearing part can be a linear function relation. The method for providing the standard functional relationship may include:
1) applying different pressures to corresponding bearing parts (for example, the bearing parts can be the same as those in the monitoring structure), and applying the pressure range and the prestressed tendon tensioning and anchoring force FpIn this regard, the pressure applied may range from 0 to 1.1FpThe number of pressure steps to be applied may be 3 to 9 (the number of pressure steps is the number of states of the magnitude of the pressure to be applied, and for example, the number of pressure steps is 3 when 0kN, 50kN, or 100kN is applied, and the number of pressure steps is 4 when 0kN, 50kN, 100kN, or 150kN is applied);
2) acquiring sensing optical fiber frequency shift data under different pressures through an optical fiber frequency shift demodulation device;
3) analyzing the frequency shift data of the induction section optical fiber section corresponding to the pressure bearing piece, and extracting a characteristic index, wherein the specific characteristic index may be a representative numerical value of the frequency shift data of the section corresponding to the induction section optical fiber, and for example, the characteristic index may be one or a combination of a maximum value, an average value, a 95 place value and the like of the frequency shift data of the induction section optical fiber section.
4) Obtaining a standard function relation between the characteristic index of the induction section optical fiber and the loaded state of the pressure-bearing piece;
the calibration method can capture the optical fiber frequency shift characteristic values under different applied loads, extract the standard function relationship between the optical fiber frequency shift characteristic index and the pressure bearing state of the pressure bearing part, and use the standard function relationship as the key processing criterion of the distributed monitoring data of the anchoring state of the prestressed tendon group.
The third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the steps of the distributed monitoring method for the anchoring state of the tendon group provided in the second aspect of the present invention.
The utility model discloses a fourth aspect provides an apparatus, include: a processor and a memory, the memory is used for storing computer programs, the processor is used for executing the computer programs stored in the memory, so that the device executes the steps of the distributed monitoring method for the anchoring state of the tendon group provided by the third aspect of the present invention.
The utility model provides a prestressing tendons crowd anchor attitude distributed monitoring structure utilizes distributed sensing optical fiber low power dissipation, long distance transmission's advantage, both regard distributed sensing optical fiber as the important component of prestressing force monitoring device (induction section optic fibre promptly), but connect monitoring device again so that the system network deployment (buffer section optic fibre promptly), thereby avoid the sensing circuit miscellaneous redundantly, data transmission and analytic efficiency can also be improved, adapt to prestressing tendons crowd anchor state on a large scale, the distributed monitoring demand. When the monitoring device is used, the characteristics of large number and wide distribution of prestressed tendon groups can be fully considered, the rapid positioning of optical fiber frequency shift data of each prestressed tendon and the induction section thereof is realized based on a data segmentation method of a window function, and meanwhile, the monitoring device is suitable for a data correction method of temperature influence and improves the accuracy of anchoring state monitoring. In addition, the specific design of each part in the monitoring structure fully considers the different functions of the sensing section optical fiber and the buffer section optical fiber, and the lengths and the layout forms of the sensing section optical fiber and the buffer section optical fiber are reasonably designed, so that the accurate monitoring and the quick positioning of the anchoring state are further realized.
The following examples further illustrate the invention of the present application, but do not limit the scope of the present application.
Example 1
Designing a distributed monitoring system for the anchoring state of a prestressed tendon group:
a full-scale test is carried out in the earthquake engineering center of Tongji university, a diagonal prestressed concrete pavement full-scale model is built, and the length of a pavement plate is 30m and the width of the pavement plate is 7 m. A prestressed steel strand with the nominal diameter of 15.2mm is selected as a prestressed tendon, and the corresponding tensioning anchoring force is 195.3 kN. Thus, the inner diameter d of the body of the pressure-bearing device1The minimum monitoring precision delta F of the anchoring state meets the following requirements:
1.05×15.2mm＝15.96mm≤d1≤1.4×15.2mm＝21.28mm
ΔF≤0.01×195.3kN＝1.953kN
finally, the inner diameter of the body of the pressure-bearing device is selected to be 20mm, and the minimum monitoring precision of the anchoring state is 1.5 kN.
The pressure-bearing device body is made of aluminum alloy materials, the elastic modulus is 50GPa, the Poisson ratio is 0.4, meanwhile, the optical fiber frequency shift demodulation device adopts a BOFDA (Brillouin optical frequency Domain analysis) demodulator, the corresponding minimum analytic frequency shift is 5 microstrains, and the minimum spatial resolution is 3 m. Thus, the sensing section fiber winding diameter d2It should satisfy:
finally, the winding diameter of the optical fiber of the selected induction section is 50 mm. Simultaneously, the number n of winding turns of the induction section optical fiber is required to satisfy:
the final selected induction section has 25 winding turns of optical fiber.
The distributed sensing optical fiber adopts a single mode optical fiber, the width of the optical fiber is 0.9mm, and therefore, the thickness h of the pressure-bearing device body and the width w of the groove on the packaging surface of the pressure-bearing device body0It should satisfy:
0.9mm×25＝22.5mm≤h≤1.2×0.9mm×25＝27mm
0.9mm≤wo≤2×0.9mm＝1.8mm
and finally, selecting the thickness of the pressure-bearing device body to be 25mm, matching the outer diameter with the winding diameter of the induction section optical fiber, and designing the thickness to be 5 cm. The width of the groove on the packaging surface of the pressure-bearing device body is 1mm, the depth of the groove is 1.2mm, and the flexible packaging material of the pressure-bearing device is polyvinyl chloride glue.
The prestressed tendons are obliquely and doubly crossed, the tension angle and the plate length form 30 degrees, and the arrangement distance of the prestressed tendons is 0.6 m. Thus, the buffer length of optical fiber LhIt should satisfy:
max(0.6m,3m)＝3m≤Lh≤1.5×3＝4.5m
finally selecting the length of the buffer section optical fiber as 4m, and laying the buffer section optical fiber in a circular arrangement mode with the diameter d3It should satisfy:
50mm≤d3≤1.5×50＝75mm
finally, the diameter of the annular layout is selected to be 70 mm.
Example 2
The method comprises the steps of carrying out indoor tests in key laboratories of the department of road and traffic engineering education of the university of the same economy, carrying out loading tests by adopting a press machine, applying different pressures to a pressure-bearing device, and acquiring corresponding frequency shift curves to obtain the standard function relationship between the loading state of the pressure-bearing device and an optical fiber correction characteristic index set. As shown in fig. 7. In the figure, the horizontal axis represents the position of the optical fiber axis, the vertical axis represents the frequency shift value of the corresponding position, 4 curves represent the frequency shift values corresponding to 100kN, 160kN, 200kN and 220kN respectively, and maximum values in the range of 1-7 m are extracted respectively as characteristic indexes. In this embodiment, the measured temperature and the calibrated temperature are matched, so that the correction value of each characteristic index is 0.
Fig. 8 shows the relationship between the applied pressure and the corrected characteristic indicator, and it can be seen that as the pressure increases, the corrected characteristic indicator (frequency shift value) increases, and the two are approximately linear, and the corresponding standard function relationship is that y is 0.00019739x + 0.004779.
Example 3
And (3) carrying out distributed monitoring data processing on the anchoring state of the prestressed tendon group:
a full-scale test is carried out in the earthquake engineering center of the university of the same institution, referring to example 1, an oblique prestressed concrete pavement is built, a prestressed tendon group anchoring state distributed monitoring system is arranged, the anchoring force of prestressed tendons is continuously changed through a jack, and data is acquired by the designed prestressed tendon group anchoring state distributed monitoring system, as shown in fig. 9. Fig. 9 shows the distributed monitoring results of the anchoring states of 10 tendons in the distributed monitoring system, wherein the conventional detection equipment (oil pressure anchor cable dynamometer) is embedded below the anchors of the 4 th, 9 th and 10 th tendons (i.e. 4#, 9#, 10 #). In the figure, the horizontal axis represents the axial distance of the distributed sensing optical fiber, and the vertical axis represents the corresponding frequency shift value on the axial distance of the distributed sensing optical fiber. It can be seen that the frequency shift curves in the figure respectively have 10 wave crests, which respectively correspond to the prestressed tendon anchoring states at the positions of 10 pressure-bearing devices. Firstly, segmenting frequency shift data by adopting a window function; since the length of the optical fiber of the sensing section is 4m and the length of the optical fiber of the buffer section is 4.5m, the window function width W1Window function spacing W2It should satisfy:
4m≤W1≤4+4.5＝8.5m
W2＝4+4.5-W1
finally selecting window function width W1Is 6m, a window function pitch W22.5m, as shown in fig. 9. Secondly, maximum values in each window are respectively extracted as characteristic indexes, and correction is carried out according to the actually measured temperature. In this embodiment, the measured temperature and the calibrated temperature are matched, so that the correction value of each characteristic index is 0.
And finally, extracting correction characteristic indexes corresponding to 10 peak sections (for example, the correction index of the first peak section is about 0.012GHz), and obtaining the anchoring state of the corresponding prestressed tendon according to the standard function relationship between the correction index and the loading state of the pressure-bearing device.
Fig. 10 shows a comparison graph of the results of the distributed monitoring system for the anchoring state of the tendon group and the results of the conventional detection equipment, the anchoring force of the 3 tendons is calculated through the reading of the oil pressure gauge, and compared with the results of the distributed monitoring system, and the detection results of the 3 oil pressure type anchor cable forcemeters are marked through scattered points in different forms in fig. 10. It can be seen that, in fig. 10, the test results of the anchoring forces of the 3 tendons at different times are marked by scattered points in different forms, the abscissa of each scattered point represents the anchoring force measured by the distributed monitoring system at a certain time, and the ordinate represents the anchoring force measured by the oil pressure type anchor cable dynamometer. Respectively carrying out linear fitting on the 3 kinds of scattered points to find the fitting precision (consistency R)2) 0.83619, 0.84003 and 0.90116 respectively have higher consistency, which shows that the monitoring result of the distributed monitoring system is consistent with the monitoring result of the hydraulic anchor cable dynamometer, and the accuracy of the monitoring system is proved.
To sum up, the utility model discloses various shortcomings in the prior art have effectively been overcome and high industry value has.
The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. A distributed monitoring structure for an anchoring state of a prestressed tendon group is characterized by comprising a pavement body (1) and distributed sensing optical fibers (4), wherein the pavement body (1) comprises a concrete structure (11) and the prestressed tendon group (12) which are distributed in a cross mode, at least part of prestressed tendons in the prestressed tendon group (12) comprises an exposed part (123) exposed out of the concrete structure (11), at least part of the exposed part (123) is sleeved with an anchoring part (3) and a pressure-bearing part (2) which are matched with each other, the pressure-bearing part (2) is located between the anchoring part (3) and the concrete structure (11), the pressure-bearing part (2) comprises an optical fiber accommodating groove (21), the distributed sensing optical fibers (4) comprise sensing section optical fibers (41) and buffer section optical fibers (42) and further comprise packaging parts (22), the sensing section optical fibers (41) are packaged in the optical fiber accommodating groove (21) through the packaging parts (22), the buffer section optical fiber (42) is positioned between the sensing section optical fibers (41).
2. The distributed monitoring structure for the anchoring state of the prestressed tendon group as claimed in claim 1, wherein the distributed sensing optical fiber (4) is a single-mode optical fiber, the tensile strength of the distributed sensing optical fiber (4) is greater than or equal to 30N, and the attenuation of the distributed sensing optical fiber (4) is less than or equal to 0.22db/km (1550 MHz).
3. The distributed monitoring structure for the anchoring state of the prestressed tendon group as claimed in claim 1, wherein the length of the sensing section optical fiber (41) on the single bearing member 2 is 4-8 m, the sensing section optical fiber (41) is a tightly-packed optical fiber, and the optical fiber winding diameter d of the sensing section optical fiber (41) is2The following formula is satisfied:
ΔF≤0.01Fp；
wherein d ispIs the nominal diameter of the prestressed tendon, E is the elastic modulus of the bearing member (2), mu is the Poisson's ratio of the bearing member (2), epsilonminThe minimum frequency shift analyzed by the induction section optical fiber (41) is shown, delta F is the minimum identification precision of the prestressed tendon anchoring state monitoring, and FpFor the tension anchorage of the tendon, dp9 to 16mm, FpIs 60 to 400 kN.
4. The distributed monitoring structure of the anchoring state of the tendon group as claimed in claim 3, wherein d is d2Is 0.6 to 0.9 mm.
5. The distributed monitoring structure for the anchoring state of the prestressed tendon group as claimed in claim 1, wherein the length of the buffer section optical fiber (42) between the two bearing members 2 is 2-6 m, the arrangement shape of the buffer section optical fiber is one or more of linear arrangement, curved arrangement and annular arrangement, and the buffer section optical fiber (42) adopts armored optical fiber.
6. The distributed monitoring structure for the anchoring state of the prestressed tendon group as claimed in claim 1, wherein the exposed part (123) of each prestressed tendon is sleeved with an anchoring member (3) and a pressure-bearing member (2) which are matched with each other, the pressure-bearing member (2) is a hollow cylinder, the outer diameter of the pressure-bearing member (2) is 5-10 cm, and the thickness h of the pressure-bearing member (2) satisfies the following formula:
wn≤h≤1.2wn；
where w is the width of the sensing section fiber 41 and d2Is the winding diameter of the optical fiber, LminFor the minimum spatial resolution of the fiber 41 resolution in the sensing section, n is the number of turns of the spiral distribution.
7. The distributed monitoring structure for the anchoring state of the prestressed tendon group as claimed in claim 6, wherein h is 2-4 cm.
8. The distributed monitoring structure for the anchoring state of the prestressed tendon group as claimed in claim 1, wherein the bearing member (2) comprises one or more optical fiber receiving grooves (21) having the same extending direction as the bearing member (2), the number of the optical fiber receiving grooves (21) in a single bearing member (2) is 1-14, and the inner diameter d of the optical fiber receiving groove (21) is 1-141The following formula is satisfied:
1.05dp≤d1≤1.4dp；
wherein d ispIs the nominal diameter of the tendon.
9. The distributed monitoring structure of the anchored state of the tendon group as claimed in claim 8, wherein d is1Is 1.5-3 cm.
10. The distributed monitoring structure for the anchoring state of the prestressed tendon group as claimed in claim 1, wherein the optical fiber accommodating groove (21) is distributed on the side surface of the pressure-bearing member (2), the depth of the optical fiber accommodating groove (21) is 1-2 mm, and the width of the optical fiber accommodating groove (21) is 1-2 mm;
the induction section optical fibers (41) are spirally and uniformly distributed on the side surface of the pressure-bearing part (2), and the number of spirally distributed turns n meets the following formula:
wherein L isminMinimum spatial resolution resolved for the sensing segment fiber (41);
the packaging part (22) is a flexible packaging part, and the packaging part (22) is bonded with the pressure-bearing part (2) through an adhesive;
the optical fiber frequency shift demodulation device (5) is in signal connection with the distributed sensing optical fiber (4), and the optical fiber frequency shift demodulation device (5) is selected from one of BOTDA, BOTDR and BOFDA.
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