Device for monitoring anchorage zone of cable and method for early warning of sealing failure

Abstract

The application discloses a kind of cable anchorage zone monitoring devices and sealing failure early warning method, monitoring device includes pre-buried pipe, waterproof cover, pre-buried pipe mouth seal and first temperature and humidity sensor or / and water sensor, cable is located in pre-buried pipe, and cable is from pre-buried pipe mouth that pipe is away from anchor cup and is worn out;Waterproof cover is simultaneously sleeved in pre-buried pipe and cable outside, and pre-buried pipe mouth that pipe is away from anchor cup is located in waterproof cover inside;Pre-buried pipe mouth seal is located at pre-buried pipe mouth that pipe is away from anchor cup, pre-buried pipe mouth seal, waterproof cover and cable form a closed cavity between them;First temperature and humidity sensor or / and water sensor is located in closed cavity.This application establishes the standard of different sensor monitoring waterproof cover sealing effect judgment, accurately monitors the sealing effect of waterproof cover by temperature, humidity, water level combination, and truly reflects sealing condition.

Description

Technical Field

[0001] This invention belongs to the field of suspension cable technology, specifically a monitoring device for monitoring the effectiveness of waterproof sealing in the anchorage area of ​​cables and a method for early warning of sealing failure. Background Technology

[0002] In cable-stayed bridges, cables are crucial load-bearing components. Failure of the waterproof cover at the embedded pipe opening can lead to water ingress into the anchorage area, causing damage and corrosion to the cable anchor heads, thus affecting the cable's lifespan and posing a potential hazard for bridge collapse. Currently, bridge waterproof covers claim excellent waterproofing performance and have passed various watertightness tests. However, during actual bridge installation, varying worker skill levels and prolonged exposure to vibration or heavy loads can cause seal failure. Therefore, effectively verifying the installation of waterproof covers and ensuring timely maintenance after seal failure are key to extending cable lifespan and reducing maintenance costs throughout the cable's service life.

[0003] Chinese utility model patent (CN217399410U, 2022-09-09) discloses a sealing device for the lower anchorage area of ​​a cable, including an anchor, an anchor point connecting plate, a waterproof cover, a sealing circular tube, and a sealing cylinder. The waterproof cover is a two-piece structure spliced ​​into a ring. One end of the waterproof cover is connected to the sealing cylinder, and the other end is connected to the upper end of the sealing circular tube. An annular flange is provided on the lower end face of the sealing circular tube, and the annular flange is connected to the anchor point connecting plate. However, this sealing device for the lower anchorage area of ​​a cable cannot accurately determine the sealing condition inside the waterproof cover during operation.

[0004] Chinese invention patent (CN104929042A, 2015-09-23) discloses a sealed anchor cable and its manufacturing and installation method for a waterproof early warning system for cable anchorage zones. The early warning system includes a cable body, an anchorage for anchoring the cable body to an anchor plate, a pre-embedded pipe, a protective cover at the anchorage end, and a waterproof cover at the other end of the pre-embedded pipe. The protective cover at the anchorage end has an air injection valve I, and the other end of the pre-embedded pipe away from the anchorage end is equipped with an air injection valve II. The pre-embedded pipe is filled with inert gas to isolate the anchorage from oxygen and moisture. A pressure early warning system consisting of a pressure sensor, a data acquisition instrument, a central processing unit, and a data transmitter is connected to the outlets of air injection valves I and II, respectively. When the air pressure in the pre-embedded pipe is lower than a certain pressure value, an early warning signal is provided and transmitted to the bridge maintenance unit or individual via mobile data transmission. The early warning system is based on a pressure sensor. However, because the pressure sensor needs to be operated in conjunction with the air injection valve, and the airtightness is difficult to achieve, the later maintenance and operation are relatively complicated and troublesome. Summary of the Invention

[0005] This invention aims to propose a monitoring device for cable anchorage zones and a method for early warning of sealing failure. It is easy to construct and operate on-site, and the subsequent data collection and reading are convenient. The judgment criteria are simple and easy to implement. Furthermore, it can use different numbers of temperature and humidity sensors, combinations of temperature and humidity sensors and water accumulation sensors, or water accumulation sensors alone for monitoring, depending on the actual site conditions, to meet the application needs of different occasions.

[0006] The technical solution of the present invention is as follows:

[0007] The cable anchorage zone monitoring device includes,

[0008] The cable is located in the pre-embedded pipe and exits from the pipe opening away from the anchor cup.

[0009] A waterproof cover is fitted over both the embedded pipe and the cable, with the opening of the embedded pipe furthest from the anchor cup located inside the waterproof cover.

[0010] The pre-embedded pipe opening is sealed, and the pre-embedded pipe opening is located at the pipe opening of the pre-embedded pipe away from the anchor cup. A closed cavity is formed between the pre-embedded pipe opening seal, the waterproof cover and the cable.

[0011] The first temperature and humidity sensor and / or water accumulation sensor are located within a closed cavity.

[0012] Alternatively, the first temperature and humidity sensor and / or water accumulation sensor is located near the junction of the pre-embedded pipe opening seal and the cable.

[0013] When the closed cavity contains only the first temperature and humidity sensor, it also includes a second temperature and humidity sensor. The second temperature and humidity sensor is located outside the closed cavity and is placed in the pre-embedded pipe below the junction of the pre-embedded pipe opening seal and the pre-embedded pipe.

[0014] A method for early warning of seal failure using the aforementioned cable anchorage zone monitoring device:

[0015] When the sealed cavity contains only the first temperature and humidity sensor and the humidity value of the first temperature and humidity sensor remains unchanged for a period of time, the seal is judged to be effective by observing the relationship between the ratio of the humidity change value ΔH to the temperature change value ΔT measured by the first temperature and humidity sensor within the time period Δt, ΔH / ΔT, and the constant a. When the ratio ΔH / ΔT ≤ a, the seal is effective; when the ratio ΔH / ΔT > a, the seal is ineffective.

[0016] It should be noted that the reason for waiting for the humidity value to stabilize for a period of time in the above method is to eliminate the influence of dehumidification measures (such as desiccants) on humidity. This is because, in order to extend the maintenance cycle, reduce maintenance costs, and make the judgment of the sealing effect more accurate, the common practice is to place desiccants or any other dehumidification method in the sealed cavity. The purpose is to keep the humidity in the sealed cavity at a low value, providing a sufficiently large humidity variation range for judging humidity changes, and facilitating the judgment of the relationship between temperature and humidity. Without dehumidification, the initial humidity in the sealed cavity can easily be very high, causing the humidity to exceed the preset alarm value within a short period of time, thus triggering a failure alarm. Therefore, dehumidification is necessary to extend the working time of the monitoring device (to a longer period without triggering a failure alarm). In addition, since waterproofing may not have been properly implemented during the installation of the waterproof cover and the sealing of the pre-embedded pipe openings, high humidity may occur immediately after installation, triggering an alarm, which is also detrimental to the judgment of the sealing effect. Therefore, dehumidification is still necessary. When the humidity is low, the relationship between temperature and humidity is unrelated to whether dehumidification is needed. However, if the humidity is high, the relationship between temperature and humidity will change, mainly due to the effects of water vaporization or condensation. In this case, dehumidification is required.

[0017] A method for early warning of seal failure using the aforementioned cable anchorage zone monitoring device:

[0018] When a sealed cavity contains both a first temperature and humidity sensor and a water accumulation sensor, and the humidity value of the first temperature and humidity sensor remains unchanged for a period of time, the following criteria are used to determine whether the seal has failed:

[0019] The relationship between the ratio of humidity change value ΔH to temperature change value ΔT measured by the first temperature and humidity sensor during the observation period Δt, ΔH / ΔT, and the constant a is observed. When the ratio ΔH / ΔT > a or the water accumulation sensor is triggered, the seal fails.

[0020] A method for early warning of seal failure using the aforementioned cable anchorage zone monitoring device:

[0021] When the sealed cavity contains only a water accumulation sensor and the water accumulation sensor is triggered, the seal fails.

[0022] A method for early warning of seal failure using the aforementioned cable anchorage zone monitoring device:

[0023] When the humidity value of the first temperature and humidity sensor remains unchanged for a period of time, the humidity change value ΔH1 measured by the first temperature and humidity sensor and the humidity change value ΔH2 measured by the second temperature and humidity sensor within the time period Δt are compared to determine whether the seal of the pre-embedded pipe opening is effective. When ΔH2 / Δt > ΔH1 / Δt > constant a, the seal of the pre-embedded pipe opening fails. At this time, the humidity value H1 measured by the first temperature and humidity sensor and the humidity value H2 measured by the second temperature and humidity sensor are compared. When H1 > H2, the seal of the waterproof cover fails.

[0024] Alternatively, the constant a = 0.5.

[0025] Regarding the three sealing failure early warning methods mentioned above, when the humidity value H1 measured by the first temperature and humidity sensor is greater than 70% and less than 85%, it indicates that there is a small amount of condensation in the sealed cavity, and the treatment measure of continued observation is adopted. When the humidity value H1 measured by the first temperature and humidity sensor is greater than 85%, it indicates that there is a small amount of water accumulation in the sealed cavity, and waterproof maintenance treatment needs to be carried out as soon as possible.

[0026] Compared with the prior art, the present invention has the following characteristics:

[0027] (1) A method was proposed to determine the sealing effect of waterproof cover installation by the relationship between humidity and temperature;

[0028] (2) A monitoring area is formed by combining the seal at the pre-embedded pipe opening with the inner cavity of the waterproof cover. The process is simple and easy to operate.

[0029] (3) A variety of different sensor combination schemes were proposed, and waterproof cover sealing failure criteria were designed for different needs;

[0030] (4) The monitoring device is simple in structure, highly reliable, and the judgment results can accurately reflect the actual sealing condition.

[0031] (5) When the combination of temperature and humidity and water accumulation monitoring functions is used, the failure of the waterproof cover seal can be detected in a timely and accurate manner and an early warning can be given to prevent water or water vapor from entering and corroding the cable anchor. Attached Figure Description

[0032] Figure 1 A schematic diagram of a monitoring device for the cable anchorage zone containing only the first temperature and humidity sensor;

[0033] Figure 2 A schematic diagram of a monitoring device for the cable anchorage zone containing only a water accumulation sensor;

[0034] Figure 3 A schematic diagram of a cable anchorage zone monitoring device that simultaneously contains a first temperature and humidity sensor and a water accumulation sensor;

[0035] Figure 4 This is a schematic diagram of a cable anchorage zone monitoring device that simultaneously contains a first temperature and humidity sensor and a second temperature and humidity sensor.

[0036] In the diagram, 1—embedded pipe; 2—waterproof cover; 3—sealed pre-embedded pipe opening; 4—first temperature and humidity sensor; 5—water accumulation sensor; 6—second temperature and humidity sensor. Detailed Implementation

[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0038] like Figures 1-4 As shown, a seal is made at the opening of the pre-embedded pipe 1 to form a pre-embedded pipe opening seal 3, creating a closed cavity inside the waterproof cover 2. A first temperature and humidity sensor 4, or a water accumulation sensor 5, or both, or both, are installed within this closed cavity. The sealing condition of the waterproof cover is determined by analyzing the data from these sensors.

[0039] Example 1:

[0040] like Figure 1 As shown, only the first temperature and humidity sensor 4 is installed inside the sealed cavity of the waterproof cover 2. At this time, the sealing condition of the waterproof cover 2 can be judged by placing a desiccant during installation or not placing a desiccant (because the outdoor humidity is low during installation, it is not necessary) to keep the humidity inside the sealed cavity at a low value. After installation, once the humidity inside the sealed cavity no longer shows a decreasing trend, the temperature and humidity changes inside the sealed cavity are observed through the first temperature and humidity sensor 4. If the humidity change is less than 0.5 times the temperature change, the waterproof cover 2 is considered to have a good sealing effect; otherwise, the seal is considered to have failed.

[0041] As an early warning system, during bridge operation, a yellow warning can be issued when the humidity of the enclosed cavity is >70% but less than 85%, indicating that there is a small amount of condensation in the enclosed cavity. The current status can be monitored. When the humidity of the cavity is >85%, a small amount of water accumulates in the surface enclosed cavity, which can be issued as a red warning. It is recommended to perform waterproof sealing maintenance as soon as possible to prevent water from re-entering the pre-embedded pipe 1 and corroding the cable anchors.

[0042] Example 2:

[0043] To achieve more accurate monitoring, relying solely on the first temperature and humidity sensor 4 inside the waterproof cover 2 is insufficient to make accurate judgments; therefore, additional sensors need to be added.

[0044] like Figure 3As shown, a water accumulation sensor 5 is added to the closed inner cavity of the waterproof cover 2. By adjusting the different installation positions of the water accumulation sensor 5, the depth of water accumulation can be determined. For example, when the water accumulation sensor 5 is positioned at the upper end of the junction between the pre-embedded pipe seal 3 and the cable body and the water accumulation sensor 5 issues an alarm (regardless of whether the first temperature and humidity sensor 4 meets the rule of judging the sealing effect by humidity and temperature in Embodiment 1), it indicates that waterproof sealing maintenance needs to be carried out as soon as possible. This solution is more accurate than relying solely on the first temperature and humidity sensor 4.

[0045] Example 3:

[0046] like Figure 4 As shown in Example 1, a second temperature and humidity sensor 6 is installed below the pre-embedded pipe opening seal 3 (i.e., inside the pre-embedded pipe 1). If the humidity measurement values ​​of both temperature and humidity sensors show an upward trend, it indicates that the pre-embedded pipe opening seal 3 has a sealing failure. Targeted maintenance should be carried out during maintenance. Then, based on the humidity levels of the two sensors, it is determined whether the waterproof cover 2 has a sealing failure. When the humidity inside the sealed cavity of the waterproof cover 2 is higher than the humidity inside the pre-embedded pipe 1, the waterproof cover 2 has a sealing failure, which is a red warning and requires maintenance as soon as possible.

[0047] Example 4:

[0048] like Figure 2 To reduce production and maintenance costs of monitoring equipment, it is also possible to install only a water accumulation sensor, using the early warning function of the water accumulation sensor 5 for maintenance. In this case, the water accumulation sensor 5 is installed on the upper end face of the pre-embedded pipe seal 3 (within the closed cavity of the waterproof cover 2).

[0049] The above are several embodiments of the present invention. Those skilled in the art can make various changes based on the above embodiments to achieve the same purpose of the present invention. However, such changes should obviously be within the scope of protection of the claims of the present invention.

Claims

1. A method for early warning of sealing failure in a cable anchorage zone monitoring device, characterized in that: The cable anchorage zone monitoring device includes, The pre-embedded pipe (1) has a cable located in it, and the cable passes through the pipe opening of the pre-embedded pipe (1) away from the anchor cup. Waterproof cover (2), which is simultaneously fitted onto the outside of the pre-embedded pipe (1) and the cable, and the opening of the pre-embedded pipe (1) away from the anchor cup is located inside the waterproof cover (2); The pre-embedded pipe opening seal (3) is located at the pipe opening of the pre-embedded pipe (1) away from the anchor cup. The pre-embedded pipe opening seal (3), the waterproof cover (2) and the cable form a closed cavity. The closed cavity is dehumidified so that the humidity inside the closed cavity is at a low value. The first temperature and humidity sensor (4) is located in the closed cavity and is close to the junction of the pre-embedded pipe seal (3) and the cable. It also includes a second temperature and humidity sensor (6), which is located outside the closed cavity and is placed in the pre-embedded pipe (1) below the junction of the pre-embedded pipe seal (3) and the pre-embedded pipe (1); When the humidity value of the first temperature and humidity sensor (4) remains unchanged for a period of time, the humidity change value ΔH1 measured by the first temperature and humidity sensor (4) and the humidity change value ΔH2 measured by the second temperature and humidity sensor (6) within the time period Δt are compared to determine whether the pre-embedded pipe seal (3) is effective. When ΔH2 / Δt>ΔH1 / Δt>constant a, the seal of the pre-embedded pipe seal (3) fails. At this time, the humidity value H1 measured by the first temperature and humidity sensor (4) and the humidity value H2 measured by the second temperature and humidity sensor (6) are compared. When H1>H2, the seal of the waterproof cover (2) fails.

2. The method for early warning of sealing failure of a cable anchorage zone monitoring device according to claim 1, characterized in that: The constant a = 0.

5.

3. The method for early warning of sealing failure of a cable anchorage zone monitoring device according to claim 1, characterized in that: When the humidity value H1 measured by the first temperature and humidity sensor (4) is greater than 70% and less than 85%, it indicates that there is a small amount of condensation in the closed cavity. Continue to observe and take other measures. When the humidity value H1 measured by the first temperature and humidity sensor (4) is greater than 85%, it indicates that there is a small amount of water accumulation in the closed cavity. Waterproofing maintenance should be carried out as soon as possible.

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