Bridge pier scouring depth dynamic monitoring device and monitoring method

Abstract

The invention relates to a dynamic monitoring device and method for the scouring depth of a bridge pier, and the device comprises a driving mechanism which is connected with a measuring line, the measuring line is connected with a heavy hammer, and the driving mechanism is configured to drive the measuring line to be released and retracted, judge the moment t when the heavy hammer falls to a riverbed, and monitor the length Lt of the measuring line at the moment t; the monitoring module is used for monitoring an included angle theta t between the measuring line at the t moment and the gravity direction; the calculation module is used for calculating the distance H between the riverbed and the pier scouring depth dynamic monitoring device based on the length Lt of the measuring line and the included angle theta t between the measuring line at the t moment and the gravity direction; the control module is in signal connection with the driving mechanism, and the control module is used for controlling the driving mechanism to start measurement at regular time and recording the change of the distance H between the riverbed and the pier scouring depth dynamic monitoring device along with time. The dynamic monitoring of the scouring depth of the bridge pier can be realized by starting the dynamic monitoring device for the scouring depth of the bridge pier at regular time.

Description

Technical Field

[0001] This application relates to the technical field of bridge monitoring, and particularly to a dynamic monitoring device and method for the scour depth of bridge piers. Background Art

[0002] Currently, the scour of bridge pier foundations is an important factor affecting the stability and safety of bridges. Especially in extreme weather conditions such as floods and heavy rainfall, scour may cause serious damage to the bridge structure and even lead to the collapse of the bridge. Therefore, dynamic monitoring of the scour depth of bridge piers is a necessary means to prevent bridges from collapsing due to excessive scour.

[0003] In related technologies, currently, scour detection technologies such as sonar imaging, ground penetrating radar, and underwater robots are relatively mature, but the equipment cost is high and the usage frequency is low, which cannot meet the requirements of dynamic monitoring of scour depth. In the field of scour depth monitoring, it is still in the stage of exploring monitoring schemes, and no mature, effective, economical, and popularizable technical means have been seen.

[0004] The existing monitoring schemes can be roughly divided into device types and instrument types. Device types such as gravity devices (plumb bobs), buoyancy devices (buoys), magnetic tags, etc. use trigger-type sensing and can only be used once. Instrument types can be divided into contact type and non-contact type. The contact type mainly uses various types of sensing rods, such as strain rods, conductivity rods, thermal conductivity rods, vibration rods, etc. The installation of the rods is difficult and it has no promotion value. The non-contact type mainly uses sonar depth sounders and red and green lasers. The former is limited by the measurement principle, needs to be installed below the water surface, is greatly affected by the water level, and requires a relatively slow flow rate. The latter can be installed above the water surface, but is only applicable to static or relatively slow-flowing clear waters. In summary, the existing monitoring schemes cannot meet the engineering requirements of dynamic monitoring of the scour depth of bridge piers.

[0005] Therefore, it is necessary to design a new dynamic monitoring device for the scour depth of bridge piers to overcome the above problems. Summary of the Invention

[0006] This application provides a dynamic monitoring device and method for the scour depth of bridge piers, which can solve the technical problem that the existing monitoring schemes in related technologies cannot meet the dynamic monitoring of the scour depth of bridge piers.

[0007] In a first aspect, an embodiment of this application provides a dynamic monitoring device for the scour depth of bridge piers, which includes: a driving mechanism, the driving mechanism is connected with a measuring line, and the measuring line is connected with a plumb bob. The driving mechanism is configured to drive the measuring line to pay out and retract, and judge the moment t when the plumb bob falls to the riverbed, and monitor the length L of the measuring line at time t t ; a monitoring module, the monitoring module is used to monitor the angle θ between the measuring line and the direction of gravity at time t t ; a calculation module, which is used to based on the length L of the measuring linet and the included angle θ between the measuring line and the gravity direction at time t t , calculate the distance H between the riverbed and the dynamic monitoring device for the scour depth of the bridge pier; a control module, which is signal-connected to the driving mechanism, and the control module is used to control the driving mechanism to start measuring regularly and record the change of the distance H between the riverbed and the dynamic monitoring device for the scour depth of the bridge pier over time.

[0008] In combination with the first aspect, in an embodiment, the driving mechanism includes a driving motor and a wire reel installed on the rotating shaft of the driving motor, and the measuring line is wound around the wire reel; the driving motor is electrically connected to the control module, and the control module is used to control the driving motor to start measuring regularly, and the chip built in the driving motor is used to judge the moment t when the plumb bob falls to the riverbed, and monitor the length L of the measuring line at time t t .

[0009] In combination with the first aspect, in an embodiment, the monitoring module includes a macro camera and a measurement module. The macro camera is arranged on one side of the wire outlet of the wire reel. The macro camera is used to collect an image with the wire outlet of the measuring line as the center of the circle, the gravity direction as the starting point of the included angle, and the measuring line as the ending point of the included angle; the measurement module is used to automatically calculate the included angle θ between the measuring line and the gravity direction at time t through machine vision measurement technology t .

[0010] In combination with the first aspect, in an embodiment, a dynamic torque sensor is installed on the rotating shaft of the driving motor, and the dynamic torque sensor is used to measure the torque of the rotating shaft; the chip built in the driving motor is used to judge the moment t when the plumb bob falls to the riverbed based on the torque of the rotating shaft.

[0011] In combination with the first aspect, in an embodiment, the driving motor is used to monitor the timing data of the current I therein, and determine the moment t when the plumb bob falls to the riverbed based on the moment of mutation of the timing data of the current I.

[0012] In a second aspect, an embodiment of the present application provides a method for dynamically monitoring the scour depth of a bridge pier. The method for dynamically monitoring the scour depth of a bridge pier uses a dynamic monitoring device for the scour depth of a bridge pier for monitoring. The method for dynamically monitoring the scour depth of a bridge pier includes:

[0013] Install the dynamic monitoring device for the scour depth of the bridge pier in the area to be measured and record the installation height;

[0014] Control the driving mechanism in the dynamic monitoring device for the scour depth of the bridge pier to regularly drive the measuring line to be released, so that the plumb bob at one end of the measuring line falls;

[0015] Judge the moment t when the plumb bob falls to the riverbed, and monitor the length L of the measuring line at time t tand the angle θ between the measuring line and the gravity direction at time t t ;

[0016] Based on the length L of the measuring line t and the angle θ between the measuring line and the gravity direction at time t t , calculate the distance H between the riverbed and the dynamic monitoring device of the pier scour depth.

[0017] Combined with the second aspect, in an embodiment, the driving mechanism includes a driving motor and a wire reel installed on the driving motor, and the measuring line is wound around the wire reel. Determining the moment t when the plumb bob falls to the riverbed includes:

[0018] Monitoring the timing data of the current I in the driving motor, and determining the moment t when the plumb bob falls to the riverbed based on the moment of mutation of the timing data of the current I.

[0019] Combined with the second aspect, in an embodiment, monitoring the timing data of the current I in the driving motor and determining the moment t when the plumb bob falls to the riverbed based on the moment of mutation of the timing data of the current I includes:

[0020] Monitoring the timing data {I i} of the current I in the driving motor; i = 1, 2, 3,..., N;

[0021] Calculating the difference {J i} of the timing data of the current I in the driving motor; i = 1, 2, 3,..., N - 1; J i = I i+1 - I i ;

[0022] Obtaining the set S of the differences of the timing data within the sliding window i = {J i , J i+1 ,..., J i+n-1}; i = 1, 2,..., N - n + 1, and sequentially calculating the standard deviation {γ i} of the data within each sliding window; i = 1, 2,..., N - n + 1; where n is the number of sliding windows;

[0023] Judging whether γ t is less than the set threshold η, t ∈ {i}, if so, the timing data of the current I mutates at this time, and this moment is the moment t when the plumb bob falls to the riverbed.

[0024] Combined with the second aspect, in an embodiment, the driving mechanism includes a driving motor and a wire reel installed on the driving motor, and the measuring line is wound around the wire reel. Monitoring the length L of the measuring line at time t t , includes:

[0025] Monitor the number of high - level pulse signals and low - level pulse signals of the drive motor at time t;

[0026] Based on the radius R of the wire reel, the angle Δφ that the drive motor rotates when receiving a high - level pulse signal or a low - level pulse signal, and the number of high - level pulse signals and low - level pulse signals at time t, calculate the length L of the measured wire at time t t 。

[0027] Combined with the second aspect, in an embodiment, the angle θ between the measured wire and the gravity direction at time t t The calculation method is as follows:

[0028] Use a macro camera to collect an image with the outlet of the measured wire as the center of the circle, the gravity direction as the starting point of the included angle, and the measured wire as the ending point of the included angle, and automatically calculate the angle θ between the measured wire and the gravity direction at time t through machine vision measurement technology t 。

[0029] The beneficial effects brought by the technical solution provided by the embodiments of the present application include:

[0030] Through the drive mechanism, the measured wire can be driven to be released and retracted, so that the weight at one end of the measured wire falls to the riverbed, and by monitoring the length L of the measured wire when the weight falls to the riverbed t And the included angle θ between the measured wire and the gravity direction at this time t , the distance H between the riverbed and the dynamic monitoring device for the scour depth of the bridge pier can be calculated. By regularly starting the dynamic monitoring device for the scour depth of the bridge pier, the dynamic monitoring of the scour depth of the bridge pier is realized, and the technical problem that the existing monitoring solutions in the related art cannot meet the dynamic monitoring of the scour depth of the bridge pier is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 It is a schematic structural diagram of a dynamic monitoring device for the scour depth of a bridge pier provided by an embodiment of the present application;

[0033] Figure 2 It is a schematic layout diagram at the outlet of the measured wire provided by an embodiment of the present application;

[0034] Figure 3 It is a flowchart of a dynamic monitoring method for the scour depth of a bridge pier provided by an embodiment of the present application;

[0035] Figure 4 The time history curves of the current, pulse number of the stepping motor, and the included angle between the measuring line and the gravity direction provided by the embodiments of the present application;

[0036] Figure 5 The time history curve of the distance from the riverbed to the installation position of the dynamic monitoring device for the scour depth of the bridge pier changing with time provided by the embodiments of the present application.

[0037] In the figure:

[0038] 1. Driving mechanism; 11. Driving motor; 12. Wire reel; 121. Wire outlet;

[0039] 2. Measuring line; 3. Plumb bob; 4. Monitoring module; 5. Industrial control computer;

[0040] 6. Macro camera; 100. Field of view area; 200. Riverbed. Detailed implementation manners

[0041] In order to enable those skilled in the art of the present technology to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0042] The embodiments of the present application provide a dynamic monitoring device and a monitoring method for the scour depth of a bridge pier, which can solve the technical problem that the existing monitoring solutions in the related art cannot meet the dynamic monitoring of the scour depth of the bridge pier.

[0043] See Figure 1 As shown, a dynamic monitoring device for the scour depth of a bridge pier provided by the embodiments of the present application includes: a driving mechanism 1, the driving mechanism 1 is connected with a measuring line 2, and the measuring line 2 is connected with a plumb bob 3. The driving mechanism 1 is configured to drive the measuring line 2 to be released and retracted, and determine the moment t when the plumb bob 3 falls to the riverbed, and monitor the length L of the measuring line 2 at the moment t t ; a monitoring module 4, the monitoring module 4 is used to monitor the included angle θ between the measuring line 2 and the gravity direction at the moment t t ; a calculation module, which is used to based on the length L of the measuring line 2 t and the included angle θ between the measuring line 2 and the gravity direction at the moment t t, calculate the distance H between the riverbed 200 and the dynamic monitoring device for the scour depth of the pier; a control module, which is signal-connected to the driving mechanism 1, and the control module is used to control the driving mechanism 1 to start measuring regularly and record the change of the distance H between the riverbed 200 and the dynamic monitoring device for the scour depth of the pier over time.

[0044] See Figure 1 As shown, when in use, the dynamic monitoring device for the scour depth of the pier is installed on the side of the pier or the main girder in the area to be measured. After installation, the installation height of the dynamic monitoring device for the scour depth of the pier needs to be recorded. The driving mechanism 1 is connected with a plumb bob 3 through a measuring line 2. The driving mechanism 1 can drive the measuring line 2 to be released and retracted. After the measuring line 2 is released, the plumb bob 3 slowly falls under the action of gravity. The plumb bob 3 successively passes through media such as air and water to reach the riverbed 200. After the measurement is completed, the measuring line 2 is slowly retracted through the driving mechanism 1, and the plumb bob 3 is slowly lifted under the traction of the measuring line 2. When the plumb bob 3 returns to the initial position, the driving mechanism 1 stops working and waits for the next measurement. In this embodiment, the scour depth measurement frequency can be set in the control module to control the dynamic monitoring device for the scour depth of the pier to start measuring regularly and record the change of the scour depth measurement result over time, so as to realize the dynamic monitoring of the scour depth of the pier. The above-mentioned dynamic monitoring device for the scour depth of the pier may include an industrial control computer 5, and the industrial control computer 5 includes the above-mentioned calculation module and control module.

[0045] In this embodiment, the driving mechanism 1 can drive the measuring line 2 to be released and retracted. After the measuring line 2 is released, the plumb bob 3 at one end of the measuring line 2 falls to the riverbed 200. And during the falling process of the plumb bob 3, by monitoring the length L of the measuring line 2 when the plumb bob 3 falls to the riverbed 200 t and the included angle θ between the measuring line 2 and the direction of gravity at this time t , based on the length L of the measuring line 2 t and the included angle θ between the measuring line 2 and the direction of gravity t , the distance H between the riverbed 200 and the dynamic monitoring device for the scour depth of the pier can be calculated. By regularly starting the dynamic monitoring device for the scour depth of the pier, the dynamic monitoring of the scour depth of the pier is realized. And this embodiment does not need to use a sounding rod, the installation is relatively easy, and it does not need to be installed below the water surface, solving the technical problem that the existing monitoring solutions in the related art cannot meet the dynamic monitoring of the scour depth of the pier.

[0046] Further, in one embodiment, the driving mechanism 1 includes a driving motor 11 and a wire reel 12 installed on the rotating shaft of the driving motor 11, and the measuring line 2 is wound around the wire reel 12; the driving motor 11 is electrically connected to the control module, and the control module is used to control the driving motor 11 to start measuring regularly. The chip built in the driving motor 11 is used to judge the moment t when the plumb bob 3 falls to the riverbed, and to monitor the length L of the measuring line 2 at the moment t t。In this embodiment, the drive motor 11 is preferably a stepper motor. Of course, other types of motors can also be used. The control module can send pulse signals of high level or low level to the drive motor 11 to control the drive motor 11 to rotate forward and backward by a certain angle Δφ. When the drive motor 11 rotates, the rotating shaft of the drive motor 11 drives the wire reel 12 to rotate, realizing the release and retraction of the measuring wire 2. And the drive motor 11 in this embodiment is built-in with a chip, and the intelligent algorithm stored in the chip can automatically judge the moment t when the weight 3 falls to the riverbed 200 and monitor the length L of the measuring wire 2 at the moment t t , and the monitoring module 4 can monitor the angle θ between the measuring wire 2 and the direction of gravity at the moment t t . When the stepper motor receives a pulse signal of high level or low level, the rotating shaft will rotate forward or backward by a certain angle Δφ, and the number N of high-level pulse signals is recorded respectively + and the number N of low-level pulse signals - . Add 1 to the high level of the pulse number and subtract 1 from the low level. The radius of the wire reel 12 around which the measuring wire 2 is wound is R. Then the calculation formula for the length of the measuring wire 2 is: L = Δφ / 180·π(N + -N - )R. If it is necessary to improve the measurement accuracy, an encoder can be added to the rotating shaft to measure the length of the measuring wire 2

[0047] In other embodiments, other drive mechanisms 1 can also be used to drive the release and retraction of the measuring wire 2

[0048] Further, in one embodiment, as shown in Figure 2 , the monitoring module 4 includes a macro camera 6 and a measurement module. The macro camera 6 is arranged on one side of the wire outlet 121 of the wire reel 12. The macro camera 6 is used to collect an image with the wire outlet 121 of the measuring wire 2 as the center of the circle, the direction of gravity as the starting point of the included angle, and the measuring wire 2 as the ending point of the included angle; the measurement module is used to automatically calculate the angle θ between the measuring wire 2 and the direction of gravity at the moment t through machine vision measurement technology t . In this embodiment, the weight 3 is affected by the wind load in the air and the water flow impact load in the water, causing the measuring wire 2 to deviate from the direction of gravity and form a certain angle θ. A macro camera 6 is arranged on the side of the wire outlet 121 of the measuring wire 2 to collect an image with the wire outlet 121 as the center of the circle, the marked direction of gravity as the starting point of the included angle, and the measuring wire 2 as the ending point of the included angle. The angle θ between the measuring wire 2 and the direction of gravity can be automatically calculated through machine vision measurement technology

[0049] In some embodiments, the monitoring module 4 can also be a macro camera 6, and the measurement module is located in the industrial control computer 5. The image monitored by the macro camera 6 is sent to the industrial control computer 5, and the measurement module in the industrial control computer 5 automatically calculates the angle θ between the measuring wire 2 and the direction of gravity

[0050] Further, in one embodiment, the drive motor 11 is configured to monitor the timing data of the current I in the drive motor 11, and determine the moment t when the weight 3 falls onto the riverbed 200 based on the moment of mutation of the timing data of the current I. In this embodiment, at the start of the measurement, the measuring line 2 is slowly released, and the weight 3 slowly falls under the action of gravity. The weight 3 passes through media such as air and water in sequence and reaches the riverbed 200. When the weight 3 lands on the riverbed 200, the tension T in the measuring line 2 suddenly changes. The moment t of the sudden change in the tension of the measuring line 2 can be automatically judged by an intelligent algorithm. At this moment, the length of the measuring line 2 is L t , and the angle between the measuring line 2 and the direction of gravity is θ t , then the distance from the riverbed 200 to the dynamic monitoring device for the scour depth of the bridge pier is: H = L t cos(θ t / 180 * π). Since the radius R of the wire reel 12 around which the measuring line 2 is wound is fixed, the tension T in the measuring line 2 is linearly and positively correlated with the torque M of the rotating shaft, and the torque M of the rotating shaft is linearly and positively correlated with the current I in the stepper motor. Therefore, there is the following relationship: T = a·I, where a is a constant. That is, the change in the tension in the measuring line 2 can be monitored by monitoring the change in the current in the stepper motor. In this embodiment, by monitoring the timing data of the current I in the drive motor 11, the moment t when the weight 3 falls onto the riverbed 200 can be determined based on the moment of mutation of the timing data of the current I

[0051] In some alternative embodiments, in order to improve the measurement accuracy, a dynamic torque sensor may be installed on the rotating shaft of the drive motor 11, and the dynamic torque sensor is used to measure the torque of the rotating shaft; the chip built in the drive motor is configured to determine the moment t when the weight 3 falls onto the riverbed 200 based on the torque of the rotating shaft. In this embodiment, a dynamic torque sensor is added on the rotating shaft to measure the torque of the rotating shaft, so as to reflect the change in the tension in the measuring line 2, and the measurement accuracy can be improved

[0052] In the above embodiment, the tension T in the measuring line 2 is linearly and positively correlated with either the current I in the stepper motor or the torque M of the rotating shaft. It is possible to automatically judge the moment t of mutation of the timing data of any one of the physical quantities by an intelligent algorithm. In this embodiment, the timing data {I i}; i = 1, 2, 3, N{I i}; i = 1, 2, 3,..., N of the current I directly measured in the stepper motor is taken as an example for illustration. There are various types of intelligent algorithms for automatically judging the mutation of timing data. Here, one algorithm is given in combination with the data change characteristics of the current I in the stepper motor during the measurement process

[0053] The environmental noise influence on the weight 3 is much greater than that on the measuring line 2. After the weight 3 reaches the riverbed 200, the fluctuation of the timing data is significantly reduced. The mutation can be judged according to the standard deviation of the difference of the timing data. Calculate the difference {J of the timing data of the current I in the stepper motori}; i = 1, 2, 3, ..., N - 1; J i = I i+1 - I i .

[0054] Set the number n of sliding windows, and the set of differences of the time series data within the sliding window is S i = {J i , J i+1 , ..., J i+n-1}; i = 1, 2, ..., N - n + 1, and calculate the standard deviation of the data within each sliding window in turn as {γ i}; i = 1, 2, ..., N - n + 1.

[0055] Set an appropriate threshold η. When γ t < η, where t ∈ {i}, it is considered that the time series data has a mutation at the t-th moment, and the length L t of the measuring line 2 corresponding to this moment and the angle θ t between the measuring line 2 and the gravity direction are taken, and the distance H from the riverbed 200 to the installation position of the dynamic monitoring device for pier scour depth is calculated as H = L t cos(θ t / 180 * π), which is the height of the riverbed 200 for this measurement.

[0056] See Figure 3 shown. The embodiment of the present application also provides a dynamic monitoring method for pier scour depth. The dynamic monitoring method for pier scour depth uses a dynamic monitoring device for pier scour depth for monitoring. The dynamic monitoring method for pier scour depth includes:

[0057] S1: Install the dynamic monitoring device for pier scour depth in the area to be measured and record the installation height. In this step, first determine the area to be measured for scour depth, and then install the dynamic monitoring device for pier scour depth on the side of the pier or the main girder in the area to be measured, and record the installation height.

[0058] S2: Control the driving mechanism 1 in the dynamic monitoring device for pier scour depth to drive the measuring line 2 to be released regularly, so that the weight 3 at one end of the measuring line 2 falls.

[0059] S3: Judge the moment t when the weight 3 falls to the riverbed 200, and monitor the length L t of the measuring line 2 at the moment t t and the angle θ

[0060] between the measuring line 2 and the gravity direction at the moment t t Based on the length L t, calculate the distance H between the riverbed 200 and the dynamic monitoring device for the scour depth of the pier.

[0061] In this embodiment, the dynamic monitoring device for the scour depth of the pier can adopt the dynamic monitoring device for the scour depth of the pier provided in any of the above embodiments and realize the corresponding functions, which will not be elaborated here. In this monitoring method, the weight 3 is tied to one end of the measuring line 2, and the measuring line 2 is wound around a line reel 12 with a radius of R. The line reel 12 is driven by a stepping motor to rotate forward and backward, so as to realize the release and retraction of the measuring line 2, and the physical quantities such as the length L of the measuring line 2, the angle θ between the measuring line 2 and the gravity direction, and the tension T of the measuring line 2 are monitored in real time. At the beginning of the measurement, the measuring line 2 is slowly released, and the weight 3 slowly falls under the action of gravity. The weight 3 passes through media such as air and water in turn and reaches the riverbed 200. When the weight 3 lands on the riverbed 200, the tension in the measuring line 2 suddenly changes. The moment t when the tension T of the measuring line 2 suddenly changes can be automatically judged by an intelligent algorithm. At this moment, the length of the measuring line 2 is L t , the angle between the measuring line 2 and the gravity direction is θ t , then the distance from the riverbed 200 to the dynamic monitoring device for the scour depth of the pier is: H = L t cos(θ t / 180 * π); after the measurement is completed, the measuring line 2 is slowly retracted, and the weight 3 is slowly lifted under the traction of the measuring line 2. When it returns to the initial position, the rotating shaft of the stepping motor is locked and waiting for the next measurement. Set the scour depth measurement frequency, control the dynamic monitoring device for the scour depth of the pier to start the measurement regularly, and record the change of the scour depth measurement result over time, so as to realize the dynamic monitoring of the scour depth of the pier.

[0062] In this embodiment, the line reel 12 is driven by a stepping motor to rotate forward or backward to realize the retraction and release of the measuring line 2 and the weight 3, and the length of the measuring line 2, the angle between the measuring line 2 and the gravity direction, and the tension in the measuring line 2 are monitored in real time. The sudden change of the tension in the measuring line 2 is detected by an intelligent algorithm to realize the automatic judgment of the weight 3 reaching the riverbed 200, and the distance from the riverbed 200 to the device installation position is corrected by the angle between the measuring line 2 and the gravity direction; the dynamic monitoring of the scour depth of the pier is realized by setting the measurement frequency to control the regular automatic measurement of the dynamic monitoring device for the scour depth of the pier.

[0063] Furthermore, in one embodiment, the driving mechanism 1 includes a driving motor 11 and a line reel 12 installed on the driving motor 11. The measuring line 2 is wound around the line reel 12. The step of judging the moment t when the weight 3 falls to the riverbed 200 includes: monitoring the timing data of the current I in the driving motor 11, and determining the moment t when the weight 3 falls to the riverbed 200 based on the moment of the sudden change of the timing data of the current I. In other embodiments, the moment t when the weight 3 falls to the riverbed 200 can also be determined by monitoring the tension T in the measuring line 2 or the torque M of the rotating shaft.

[0064] Further, in one embodiment, monitoring the timing data of the current I in the drive motor 11 and determining the time t when the weight 3 falls to the riverbed 200 based on the moment of mutation of the timing data of the current I includes:

[0065] S31: Monitor the timing data {I i} of the current I in the drive motor 11; i = 1, 2, 3,..., N.

[0066] S32: Calculate the difference {J i} of the timing data of the current I in the drive motor 11; i = 1, 2, 3,..., N - 1; J i = I i+1 - I i .

[0067] S33: Obtain the set S of the differences of the timing data within the sliding window i ={J i , J i+1 ,..., J i+n-1}; i = 1, 2,..., N - n + 1, and calculate the standard deviation {γ i} of the data within each sliding window in turn; i = 1, 2,..., N - n + 1; where n is the number of sliding windows.

[0068] S34: Determine whether γ t is less than the set threshold η, t ∈ {i}, if so, at this time the timing data of the current I mutates, and this moment is the time t when the weight 3 falls to the riverbed 200.

[0069] In the above embodiment, the tension T in the measuring line 2 is linearly and positively correlated with both the current I in the stepper motor and the shaft torque M. It is possible to automatically determine the mutation moment t of the timing data of any one of the physical quantities through the intelligent algorithm of the built-in chip in the stepper motor. This embodiment takes the timing data {I i}; i = 1, 2, 3,..., N{I i}; i = 1, 2, 3,..., N of the current I directly measured in the stepper motor as an example for illustration. There are various types of intelligent algorithms for automatically determining the mutation of timing data. Here, one of the algorithms is given in combination with the data change characteristics of the current I in the stepper motor during the measurement process:

[0070] The environmental noise affecting the weight 3 is much greater than that of the measuring line 2. After the weight 3 reaches the riverbed 200, the fluctuation of the timing data is significantly reduced, and the mutation can be judged according to the standard deviation of the difference of the timing data. Calculate the difference {J i} of the timing data of the current I in the stepper motor; i = 1, 2, 3,..., N - 1; J i = I i+1 - Ii 。

[0071] Set the number n of sliding windows, and the set of differences of the time series data within the sliding windows is S i ={J i , J i+1 ,..., J i+n-1}; i = 1, 2,..., N - n + 1, and calculate the standard deviations of the data within each sliding window in sequence as {γ i}; i = 1, 2,..., N - n + 1.

[0072] Set a suitable threshold η. When γ t < η, where t ∈ {i}, it is considered that a mutation has occurred in the time series data at the t-th moment, and the length L t of the measuring line 2 at this moment and the angle θ t between the measuring line 2 and the gravity direction are taken, and the distance H from the riverbed 200 to the installation position of the dynamic monitoring device for the scour depth of the pier is calculated as H = L t cos(θ t / 180 * π), which is the height of the riverbed 200 for this measurement.

[0073] Further, in an embodiment, the driving mechanism 1 includes a driving motor 11 and a wire reel 12 installed on the driving motor 11. The measuring line 2 is wound around the wire reel 12. Monitoring the length L t of the measuring line 2 at the t-th moment includes: monitoring the number of high-level pulse signals and the number of low-level pulse signals of the driving motor 11 at the t-th moment; based on the radius R of the wire reel 12, the angle Δφ by which the driving motor 11 rotates when receiving a high-level pulse signal or a low-level pulse signal, and the number of high-level pulse signals and the number of low-level pulse signals at the t-th moment, calculate the length L t of the measuring line 2 at the t-th moment.

[0074] In this embodiment, when the stepping motor receives a high-level or low-level pulse signal, the rotating shaft will rotate forward or backward by a certain angle Δφ. The number N + of high-level pulse signals and the number N - of low-level pulse signals are respectively recorded. The number of high-level pulses is increased by 1, and the number of low-level pulses is decreased by 1. The radius of the wire reel 12 around which the measuring line 2 is wound is R. Then the calculation formula for the length of the measuring line 2 is: L = Δφ / 180·π(N + - N - )R. If it is necessary to improve the measurement accuracy, an encoder can be added to the rotating shaft to measure the length of the measuring line 2.

[0075] Further, in an embodiment, the angle θ tThe calculation method is as follows: Use a macro camera 6 to collect an image with the outlet 121 of the measuring line 2 as the center of the circle, the gravity direction as the starting point of the included angle, and the measuring line 2 as the ending point of the included angle, and automatically calculate the included angle θ between the measuring line 2 and the gravity direction at time t through machine vision measurement technology. t In this embodiment, the plumb bob 3 is affected by wind load in the air and by water flow impact load in the water, causing the measuring line 2 to deviate from the gravity direction and form a certain included angle θ. A macro camera 6 is arranged on the side of the outlet 121 of the measuring line 2 to collect an image with the outlet 121 as the center of the circle, the marked gravity direction as the starting point of the included angle, and the measuring line 2 as the ending point of the included angle. Through machine vision measurement technology, the included angle θ between the measuring line 2 and the gravity direction can be automatically calculated. After identifying the moment t when the plumb bob 3 falls to the riverbed 200, take out the length L of the measuring line 2 corresponding to this moment. t And the included angle θ between the measuring line 2 and the gravity direction t Then the distance H between the riverbed 200 and the dynamic monitoring device for pier scour depth can be calculated.

[0076] The following uses Figure 1 the specific embodiment shown to illustrate the present application.

[0077] Figure 1 As shown, determine the area to be measured for pier scour depth, and install the dynamic monitoring device for pier scour depth directly above the pier in the area to be measured.

[0078] Through the preset program in the device, control the stepping motor to rotate in the reverse direction to slowly release the plumb bob 3 and the measuring line 2, and collect the number of pulse signals, the magnitude of the current in the stepping motor, and the included angle between the measuring line 2 and the gravity direction in real time during this process. During the entire process of releasing and retracting the measuring line 2, the time history curves of the current, pulse number, and included angle are as Figure 4 shown; from Figure 4 the time history curve of the current in it, it can be known that when the plumb bob 3 reaches the riverbed 200, the current suddenly decreases and the fluctuation of the current decreases. The current mutation point can be automatically identified through an intelligent algorithm, and the corresponding pulse number and included angle at this moment can be taken out, as Figure 4 shown by the marked points in it.

[0079] The layout at the outlet of the measuring line 2 of the dynamic monitoring device for pier scour depth is as Figure 2 shown, where 100 is the field of view area of the macro camera 6. The measuring line 2 rotates with the outlet 121 as the center of the circle and is within the field of view. The macro camera 6 captures the image within the field of view, and calculates the included angle θ between the measuring line 2 and the gravity direction through machine vision algorithms.

[0080] When the plumb bob 3 and the measuring line 2 are slowly released until the plumb bob 3 reaches the riverbed 200, the initial pulse number is 10934 and the final pulse number is -214491. In this example, the radius R of the wire reel 12 is 0.09 m, and when the stepping motor receives a pulse signal, it rotates by Δφ = 0.09°. Then the length of the measuring line 2 is:

[0081] L t = 0.09 / 180 * π * (10934 / 214491) * 0.09 = 31.8687 m

[0082] When the plumb bob 3 reaches the riverbed 200, the angle between the measuring line 2 and the direction of gravity is θ t = 27.25°, then the distance from the riverbed 200 to the installation position of the dynamic monitoring device for the scour depth of the pier is:

[0083] H = 31.8687 * cos(27.25 / 180 * π) = 28.3318 m

[0084] If the scour depth measurement frequency is set to once a day through a preset program, then the variation of the scour depth with time is as Figure 5 shown.

[0085] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present application. Unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0086] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0087] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A dynamic monitoring device for bridge pier scouring depth, characterized in that: It includes: A driving mechanism (1), wherein the driving mechanism (1) is connected to a measuring line (2), and the measuring line (2) is connected to a weight (3), wherein the driving mechanism (1) is configured to drive the measuring line (2) to be released and retracted, and to determine a time t when the weight (3) falls to the riverbed, and to monitor a length L of the measuring line (2) at time t t ; A monitoring module (4), the monitoring module (4) is used to monitor the angle θ between the measuring line (2) and the gravity direction at time t t ; A calculation module is used to calculate the length L of the measuring line (2) based on the length L of the measuring line (2) t and the angle θ between the measuring line (2) and the gravity direction at time t t , calculate the distance H between the riverbed and the dynamic monitoring device for the scour depth of the bridge pier; A control module is connected to the drive mechanism (1) by signal, and is used to control the drive mechanism (1) to start measuring and recording the change of the distance H between the riverbed and the bridge pier scour depth dynamic monitoring device over time.

2. The bridge pier scouring depth dynamic monitoring device according to claim 1, characterized in that: The driving mechanism (1) comprises a driving motor (11) and a wire drum (12) mounted on a rotating shaft of the driving motor (11), and the measuring line (2) is wound around the wire drum (12); The drive motor (11) is electrically connected to the control module, the control module is used to control the drive motor (11) to start measurement at a fixed time, and the chip built into the drive motor (11) is used to determine the time t when the weight (3) falls to the riverbed, and to monitor the length L of the measuring line (2) at time t. t .

3. The bridge pier scouring depth dynamic monitoring device according to claim 2, characterized in that: The monitoring module (4) comprises a macro camera (6) and a measuring module; the macro camera (6) is arranged on one side of the cable outlet (121) of the cable drum (12); the macro camera (6) is used to collect an image with the cable outlet (121) of the measuring line (2) as the center of the circle, the direction of gravity as the starting point of the angle and the measuring line (2) as the end point of the angle; and the measuring module is used to automatically calculate the angle θ between the measuring line (2) and the direction of gravity at time t by machine vision measurement technology. t .

4. The bridge pier scouring depth dynamic monitoring device according to claim 2, characterized in that: The rotating shaft of the driving motor (11) is equipped with a dynamic torque sensor, and the dynamic torque sensor is used to measure the torque of the rotating shaft; The chip built into the driving motor (11) is used to determine the time t when the heavy hammer (3) falls to the riverbed based on the torque of the rotating shaft.

5. The bridge pier scouring depth dynamic monitoring device according to claim 2, characterized in that: The driving motor (11) is used to monitor the time series data of the current I therein, and determine the time t when the weight (3) falls to the riverbed based on the time when the time series data of the current I suddenly changes.

6. A method for dynamic monitoring of bridge pier scour depth, characterized in that: The bridge pier scouring depth dynamic monitoring method uses a bridge pier scouring depth dynamic monitoring device for monitoring, and the bridge pier scouring depth dynamic monitoring method includes: Install the bridge pier scour depth dynamic monitoring device in the area to be tested and record the installation height; Controlling a driving mechanism (1) in a dynamic monitoring device for scouring depth of a bridge pier to regularly drive a measuring line (2) to be released, so that a weight (3) at one end of the measuring line (2) falls; Determine the time t when the weight (3) falls to the riverbed, and monitor the length L of the measuring line (2) at time t t and the angle θ between the measuring line (2) and the gravity direction at time t t ; Based on the length L of the measuring line (2) t and the angle θ between the measuring line (2) and the gravity direction at time t t , calculate the distance H between the riverbed and the dynamic monitoring device for the scour depth of the bridge pier.

7. The method for dynamic monitoring of bridge pier scouring depth according to claim 6, characterized in that: The driving mechanism (1) comprises a driving motor (11) and a wire drum (12) mounted on the driving motor (11), the measuring line (2) is wound around the wire drum (12), and the moment t at which the weight (3) falls to the riverbed is determined, comprising: The time series data of the current I in the driving motor (11) is monitored, and the time t when the weight (3) falls to the riverbed is determined based on the time when the time series data of the current I suddenly changes.

8. The method for dynamic monitoring of bridge pier scouring depth according to claim 7, characterized in that: The monitoring of the time series data of the current I in the driving motor (11), and determining the time t when the weight (3) falls to the riverbed based on the time when the time series data of the current I suddenly changes, comprises: Monitoring the time series data {I i }; i=1, 2, 3,..., N; Calculate the difference {J of the time series data of the current I in the drive motor (11) i }; i = 1, 2, 3, ..., N-1; J i =I i+1 -I i ; Get the set S of differences of time series data in the sliding window i ={J i ,J i+1 , ..., J i+n-1 }; i = 1, 2, ..., N-n+1, ​​and calculate the standard deviation of the data in each sliding window in turn {γ i }; i = 1, 2, ..., N-n+1; where n is the number of sliding windows; Judgment t Is it less than the set threshold η, t∈{i}? If so, the time series data of the current I changes suddenly, and this moment is the moment t when the weight (3) falls to the riverbed.

9. The method for dynamically monitoring the scouring depth of a bridge pier according to claim 6, characterized in that: The driving mechanism (1) comprises a driving motor (11) and a wire drum (12) mounted on the driving motor (11), the measuring line (2) is wound around the wire drum (12), and the length L of the measuring line (2) at the monitoring time t is t ,include: Monitoring the number of high-level pulse signals and the number of low-level pulse signals of the drive motor (11) at time t; Based on the radius R of the wire drum (12), the angle Δφ at which the driving motor (11) rotates when receiving a high-level pulse signal or a low-level pulse signal, and the number of high-level pulse signals and the number of low-level pulse signals at time t, the length L of the measuring line (2) at time t is calculated. t .

10. The method for dynamic monitoring of bridge pier scouring depth according to claim 6, characterized in that: The angle θ between the measuring line (2) and the gravity direction at time t is t The calculation method is: A macro camera (6) is used to collect an image with the outlet (121) of the measuring line (2) as the center of the circle, the direction of gravity as the starting point of the angle and the measuring line (2) as the end point of the angle, and the angle θ between the measuring line (2) and the direction of gravity at time t is automatically calculated by machine vision measurement technology. t .

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