Apparatus and method for detecting a position of a road surface collapse based on time domain reflection

Abstract

The application discloses a device and a detection method for detecting a road collapse position based on a time domain reflection method, and belongs to the technical field of road collapse detection. The device for detecting the road collapse position based on the time domain reflection method comprises a central processing unit, a timer, a driving circuit, a detection cable, a receiver and a data processing circuit. The application further discloses a detection method for detecting the road collapse position based on the device. The pulse signal generated by the central processing unit is amplified by the driving circuit and then propagated in the detection cable. When the cable is broken due to the collapse, the pulse signal is reflected back and received by the receiver. After processing, the central processing unit calculates the breakpoint position. The device and the detection method have the advantages of simple data processing process, high detection precision, real-time detection and greatly reduced detection cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road collapse detection, and in particular to a device and method for detecting a road collapse position based on time domain reflectometry. BACKGROUND

[0002] Road collapse is a process and phenomenon in which a road sinks downward under the action of natural or human factors and forms a depression or a pit on the road surface. Road collapse detection is one of the important measures to ensure road safety and maintenance. In particular, if a collapse cannot be found in time when a collapse occurs on a highway, a major accident is likely to occur. In the prior art, only road surface data is used for prediction and alarm. For example, a patent with publication number CN113325419B discloses a road collapse detection method, which uses an L-band InSAR satellite radar combined with a dual-frequency high-dynamic ground penetrating radar to achieve rapid and accurate analysis of underground hazards and provide a basis for rapid early warning and quantitative regulation of road safety hazards. However, there are still problems such as only having an early warning function, being unable to detect a collapse, complex data processing, and high equipment cost. At the same time, due to the long distance of a highway, labor intensity is high when a ground penetrating radar is used for regular detection, and it is difficult to balance the relationship between detection cost and frequency. SUMMARY

[0003] The purpose of the present application is to provide a device and method for detecting a road collapse position based on time domain reflectometry, which solves the above technical problems.

[0004] To achieve the above purpose, the present application provides a device for detecting a road collapse position based on time domain reflectometry, which comprises a central processing unit,

[0005] The central processing unit is used to generate a pulse signal and calculate a collapse position. The central processing unit is connected with a timer.

[0006] The central processing unit is connected with a detection cable through a driving circuit. The driving circuit is used to amplify the pulse signal.

[0007] The detection cable is laid along a detection road surface and is used to amplify the propagation of the pulse signal.

[0008] A receiver is connected with the central processing unit through a data processing circuit. The receiver is used to capture a signal reflected back by a breakpoint encountered by the pulse signal propagating along the detection cable.

[0009] The data processing circuit transmits the signal reflected back to the central processing unit after data processing and calculation.

[0010] Preferably, the receiver is an analog-to-digital conversion module or a TDR receiver.

[0011] Preferably, the data processing circuit comprises a filtering module, an edge detection module and a time difference calculation module, the filtering module is used to remove high-frequency noise and interference, the edge detection module is used to determine the starting point of the reflected signal, and the time difference calculation module is used to calculate the time difference between the sending pulse and the received reflected signal.

[0012] Preferably, the edge detection module comprises a second derivative calculation submodule and a threshold calculation submodule, both of which are connected with the filtering module, and when the reflected signal calculated by the second derivative calculation submodule has a zero-crossing point and the zero-crossing point is within the threshold range calculated by the threshold calculation submodule, the zero-crossing point is determined as the starting point.

[0013] Preferably, the detection cable is laid in the detection pavement through the support pipe, the support pipe comprises a plurality of connecting units, each connecting unit comprises symmetrically arranged upper and lower pipe pieces, the upper pipe piece is 8-10 cm away from the top of the detection pavement, the lower pipe piece is provided with a through hole and an arc-shaped guard plate, the optical fiber humidity sensor is arranged below the detection pavement through the through hole, the connecting wire of the optical fiber humidity sensor is arranged between the lower pipe piece and the arc-shaped guard plate, the arc-shaped guard plate is used to separate the detection wire and the connecting wire, and the connecting wire is connected with the central processor through the demodulator.

[0014] Preferably, the central processor is arranged on the guardrail of the detection pavement and electrically connected with the photovoltaic power generation and energy storage device, and the central processor is connected with a display.

[0015] A detection method of a device for detecting the collapse position of a pavement based on time domain reflection method, and the specific steps are as follows:

[0016] Step S1: laying a detection cable and arranging an optical fiber humidity sensor on a detection pavement;

[0017] Step S2: the central processor collects the humidity signal of the demodulator in real time, generates a pulse signal when the humidity reaches a first warning value, and amplifies the pulse signal through a driving circuit, the amplified pulse signal propagates along the detection cable, the receiver receives the reflected signal, and the data processing circuit removes high-frequency noise and interference, and then the edge detection module calculates the position of the starting point and the time difference between the sending pulse and the received reflected signal, the position of the reflected point is calculated according to the time difference, the reflected point is determined as a fracture point if it is within the mileage of the detection pavement, and the reflected point is determined as no fracture if it is at the end of the detection pavement.

[0018] Or the central processing unit generates a pulse signal at a set interval, and sequentially passes through the driving circuit amplification, propagation in the detection cable, reflection, reception and data processing, calculates the position of the starting point through the edge detection module and calculates the time difference between the sending pulse and the received reflection signal, calculates the reflection point position according to the time difference, and determines that the reflection point is a fracture point when the reflection point is in the detection road mileage, and determines that the road surface does not occur fracture when the reflection point is at the end of the detection road surface.

[0019] Preferably, in step S1, at least one laying groove of a set height is opened on each driving lane of the detection road surface, detection holes are arranged in the laying groove in a linear distribution, and the optical fiber humidity sensor is arranged in the detection hole, the optical fiber humidity sensor is connected to the demodulator after being inserted into the pipe piece in the laying groove, and the detection cable is placed in the pipe piece, and the upper pipe piece is installed, and the support pipe is supported by the support at a set height, and then the detection road surface is paved.

[0020] Preferably, in step S1, the detection hole is arranged before the detection road surface is paved, the optical fiber humidity sensor is arranged in the detection hole, the optical fiber humidity sensor is connected to the demodulator after being inserted into the pipe piece in the laying groove, the detection cable is placed in the pipe piece, the upper pipe piece is installed, and the support pipe is supported by the support at a set height, and then the detection road surface is paved.

[0021] Preferably, the reflection point position calculated according to the time difference is calculated according to the following formula:

[0022] ;

[0023] Wherein, D is the distance of the reflection point from the starting point, is the time difference, is the signal propagation speed related to the dielectric constant of the cable.

[0024] Therefore, the device and the detection method for detecting the collapse position of the road surface based on the time domain reflection method have the beneficial effects that:

[0025] By measuring the time difference between the pulse sending time and the reflection time, the specific position of the reflection point is calculated, so that the road collapse point is determined, the data processing process is simple and the detection precision is high, and real-time detection can be realized, so that the detection cost is greatly reduced. At the same time, the optical fiber humidity sensor is arranged to detect the humidity below the road surface in real time, trigger the collapse detection process, reduce the detection energy consumption and detection times, and ensure the detection accuracy.

[0026] The technical scheme of the present application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a principle block diagram of the device for detecting the collapse position of the road surface based on the time domain reflection method.

[0028] Figure 2 This is a structural diagram of the detection cable of the present invention installed on the road surface.

[0029] Figure Labels

[0030] 1. Road surface inspection; 2. Cable inspection; 3. Upper pipe segment; 4. Lower pipe segment; 5. Curved protective plate; 6. Fiber optic humidity sensor. Detailed Implementation

[0031] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] Example 1

[0034] like Figure 1 As shown, a device for detecting the location of road surface collapse 1 based on time-domain reflectometry includes a central processing unit, a drive circuit, a detection cable 2, a receiver, and a data processing circuit.

[0035] In this embodiment, the detection road surface 1 is 1 kilometer long (the device can be superimposed according to actual needs), and the detection cable 2 is a coaxial cable.

[0036] The central processing unit uses an STM32 microcontroller to generate pulse signals and calculate the collapse location. The central processing unit is connected to a timer, which is a high-precision timer to ensure the accuracy of the measurement.

[0037] The central processor is connected with the detection cable 2 through a driving circuit, the driving circuit is used for amplifying the pulse signal, and the cabinet in the embodiment adopts a sampling rate of 50Hz to capture the reflected signal, so that the integrity of the signal details is ensured. The detection cable 2 is laid along the detection pavement 1, and is used for propagation of the amplified pulse signal, and the driving circuit in the embodiment is a high-power driving circuit, and low-power and medium-power driving circuits can be selected for the detection pavement 1 with a short distance.

[0038] The receiver is connected with the central processor through a data processing circuit, the receiver in the embodiment is an analog-to-digital conversion module, and the receiver is used for capturing the signal reflected back by the reflected pulse signal propagating along the detection cable 2 and encountering a breakpoint. The data processing circuit receives the reflected signal, performs data processing and calculation, and then transmits the signal to the central processor. The data processing circuit includes a filtering module, an edge detection module and a time difference calculation module, the filtering module is used for removing high-frequency noise and interference, the edge detection module is used for determining the starting point of the reflected signal, and the time difference calculation module is used for calculating the time difference between the transmitted pulse and the received reflected signal.

[0039] The edge detection module includes a second derivative calculation submodule and a threshold calculation submodule, both of which are connected with the filtering module. When the reflected signal calculated by the second derivative calculation submodule has a zero-crossing point, and the zero-crossing point is within the threshold range calculated by the threshold calculation submodule, the zero-crossing point is determined as the starting point. The combination of the two edge algorithms improves the accuracy of edge detection.

[0040] In order to facilitate subsequent replacement of the detection cable 2, the detection cable 2 is laid in the detection pavement 1 through a support pipe, as shown in Figure 2 The support pipe includes a plurality of connection units, the connection unit includes symmetrically arranged upper pipe pieces 3 and lower pipe pieces 4, in Figure 2 The height H is 8cm-10cm from the top of the detection pavement 1 to the upper pipe piece 3, the lower pipe piece 4 is provided with a through hole, and the lower pipe piece 4 is provided with an arc-shaped guard plate 5. The optical fiber humidity sensor 6 is arranged below the detection pavement 1 by passing through the through hole, the connecting lead of the optical fiber humidity sensor 6 is arranged between the lower pipe piece 4 and the arc-shaped guard plate 5, the arc-shaped guard plate 5 is used for separating the detection lead and the connecting lead, and the connecting lead is connected with the central processor through a demodulator.

[0041] The central processor is arranged on the guardrail of the detection pavement 1 and is electrically connected with the photovoltaic power generation energy storage device, and is used for providing electric energy. The central processor is connected with a display for displaying the detection result.

[0042] The detection method of the device for detecting the collapse position of the detection pavement 1 based on the time domain reflection method is as follows:

[0043] Step S1: laying the detection cable 2 and arranging the optical fiber humidity sensor 6 on the detection pavement 1.

[0044] In this embodiment, the laying is carried out on the existing pavement, at least one laying groove with a set height is formed on each lane of the detection pavement 1, detection holes are linearly distributed in the laying groove, the optical fiber humidity sensor 6 is arranged in the detection hole, the optical fiber humidity sensor 6 passes through the down pipe 4 in the laying groove and is connected to the demodulator, after the detection cable 2 is placed in the down pipe 4, the upper pipe 3 is installed, and then the pavement is filled and leveled by asphalt.

[0045] Step S2: The central processor collects the humidity signal of the demodulator in real time, when the humidity reaches the first warning value, the central processor generates a pulse signal and amplifies it through the driving circuit, the amplified pulse signal propagates along the detection cable 2, the receiver receives the reflected signal, removes high-frequency noise and interference through the data processing circuit, and then calculates the position of the starting point and the time difference between the transmitted pulse and the received reflected signal through the edge detection module, the position of the reflection point is calculated according to the time difference, and the calculation formula of the position of the reflection point according to the time difference is as follows:

[0046] ;

[0047] Wherein, D is the distance of the reflection point from the starting point, is the time difference, is the signal propagation speed related to the dielectric constant of the cable. The reflection point is in the mileage of the detection pavement 1, and it is determined that the reflection point is a broken point, and the reflection point is at the end point of the detection pavement 1, and it is determined that the pavement has not been broken.

[0048] In order to verify the reliability of the method, a breakpoint is set at 100 meters, 200 meters / microsecond, and multiple detections are carried out, and the obtained data is shown in Table 1.

[0049] Table 1 Detection data

[0050] ;

[0051] The error is within 0.2 meters, which meets the requirement of short-distance accurate detection.

[0052] Embodiment 2

[0053] The difference between this embodiment and embodiment 1 is that step S1 is different, and in this embodiment, the detection is carried out when the detection pavement 1 is laid, and the specific process is as follows:

[0054] The detection hole is set before the detection pavement 1 is laid, the optical fiber humidity sensor 6 is arranged in the detection hole, the optical fiber humidity sensor 6 passes through the down pipe 4 in the laying groove and is connected to the demodulator, the detection cable 2 is placed in the down pipe 4, the upper pipe 3 is installed, the support pipe is supported by the support at a set height, and then the detection pavement 1 is laid.

[0055] Example 3

[0056] The difference between this embodiment and example 1 is that the way of collapse detection is different. In this embodiment, the central processor generates a pulse signal at a set interval for collapse detection, and then the signal is amplified by a driving circuit, propagated in the detection cable 2, reflected, received and processed. The edge detection module calculates the position of the starting point and the time difference between the sending pulse and the received reflected signal. The position of the reflection point is calculated according to the time difference. If the reflection point is within the detection road 1 mileage, it is determined that the reflection point is a breaking point. If the reflection point is at the end of the detection road 1, it is determined that the road has not been broken.

[0057] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A device for detecting the location of a road collapse based on time domain reflectometry, comprising a central processing unit, characterized in that: the central processing unit is configured to generate a pulse signal and calculate the location of the collapse; the central processing unit is connected to a timer; the central processing unit is connected to a detection cable through a drive circuit, and the drive circuit is configured to amplify the pulse signal; the detection cable is laid along a detection road surface and is configured to amplify the propagation of the pulse signal; the detection cable is laid in the detection road surface through a support pipe, and the support pipe comprises a plurality of connecting units, each connecting unit comprises symmetrically arranged upper and lower pipe pieces, the lower pipe piece is provided with a through hole and an arc-shaped guard plate is arranged in the lower pipe piece, an optical fiber humidity sensor is arranged below the detection road surface through the through hole, a connecting wire of the optical fiber humidity sensor is arranged between the lower pipe piece and the arc-shaped guard plate, the arc-shaped guard plate is configured to separate the detection wire and the connecting wire, and the connecting wire is connected to the central processing unit through a demodulator; a receiver is connected to the central processing unit through a data processing circuit, and the receiver is configured to capture the reflected signal of the pulse signal encountering a breakpoint along the detection cable; the data processing circuit receives the reflected signal, processes and calculates the reflected signal, and then transmits the processed and calculated signal to the central processing unit. The receiver is an analog-to-digital conversion module or a TDR receiver. The data processing circuit comprises a filtering module, an edge detection module, and a time difference calculation module, the filtering module is configured to remove high-frequency noise and interference, the edge detection module is configured to determine the starting point of the reflected signal, and the time difference calculation module is configured to calculate the time difference between the transmitted pulse and the received reflected signal. The edge detection module comprises a second derivative calculation submodule and a threshold calculation submodule, both of which are connected to the filtering module, when the reflected signal calculated by the second derivative calculation submodule has a zero-crossing point and the zero-crossing point is within the threshold range calculated by the threshold calculation submodule, the zero-crossing point is determined as the starting point. The upper pipe piece is 8-10 cm away from the top of the detection road surface. The central processing unit is arranged on a guardrail of the detection road surface and is electrically connected to a photovoltaic power generation and energy storage device, and the central processing unit is connected to a display.

2. The device for detecting the position of the road collapse based on the time domain reflection method according to claim 1, characterized in that: The specific steps are as follows:

3. The apparatus for detecting the position of the road collapse based on the time domain reflection method according to claim 2, characterized in that: Step S1: laying the detection cable and arranging the optical fiber humidity sensor on the detection road surface; 4. The apparatus for detecting the position of the road collapse based on the time domain reflection method according to claim 3, wherein: Step S2: the central processing unit acquires the humidity signal of the demodulator in real time, when the humidity reaches a first warning value, the central processing unit generates a pulse signal and amplifies the pulse signal through the drive circuit, the amplified pulse signal propagates along the detection cable, the receiver receives the reflected signal, removes high-frequency noise and interference through the data processing circuit, calculates the location of the starting point through the edge detection module, and calculates the time difference between the transmitted pulse and the received reflected signal, the location of the reflection point is calculated according to the time difference, if the reflection point is within the mileage of the detection road surface, it is determined that the reflection point is a broken point, and if the reflection point is at the end of the detection road surface, it is determined that the road surface has not been broken.

5. The apparatus for detecting the position of the road collapse based on the time domain reflection method according to claim 4, wherein: ​ 6. The apparatus for detecting the position of the road collapse based on the time domain reflection method according to claim 5, wherein: ​ 7. A method of detecting a position of a collapse in a road surface based on the apparatus of claim 6, characterized by, ​ ​ ​ Or in the set interval, the central processing unit generates pulse signal, and through the driving circuit amplification, propagation in the detection cable, reflection, receiving and data processing in turn, the edge detection module calculates the position of the starting point and the time difference between the sending pulse and the receiving reflection signal, the reflection point position is calculated according to the time difference, the reflection point is determined as the breaking point if it is in the detection road mileage, and the road surface is determined not to be broken if the reflection point is at the end of the detection road surface.

8. The method according to claim 7, wherein the method comprises the steps of: transmitting a signal from the transmitter; receiving the signal at the receiver; and determining the position of the collapse based on the time taken for the signal to travel from the transmitter to the receiver. In step S1, at least one laying groove with a set height is opened on each driving lane of the detection road surface, detection holes are linearly distributed in the laying groove, and the optical fiber humidity sensor is arranged in the detection hole, the optical fiber humidity sensor is connected with the demodulator after passing through the down pipe in the laying groove, the detection cable is placed in the down pipe, the upper pipe is installed, and the asphalt is filled and leveled.

9. The method of claim 7, wherein the method comprises the steps of: transmitting a signal from the transmitter; receiving the signal at the receiver; and determining the location of the signal. In step S1, the detection hole is arranged before the detection road surface is laid, the optical fiber humidity sensor is arranged in the detection hole, the optical fiber humidity sensor is connected with the demodulator after passing through the down pipe in the laying groove, the detection cable is placed in the down pipe, the upper pipe is installed, the support pipe is supported by the support at a set height, and the laying of the detection road surface is carried out.

10. The detection method of the device for detecting the location of road collapse based on time-domain reflectometry according to claim 8 or 9, characterized in that: The calculation formula of the reflection point position according to the time difference is as follows: ； where D is the distance from the reflection point to the starting point, is the time difference, is the signal propagation speed related to the dielectric constant of the cable.

Images