Device for detecting collapse position of road surface based on time domain reflection method and detection method

Abstract

The invention discloses a device for detecting a pavement collapse position based on a time domain reflection method and a detection method, and belongs to the technical field of pavement collapse detection, and the device for detecting the pavement 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. Meanwhile, the invention discloses a detection method of the device for detecting the collapse position of the road surface based on the time domain reflection method, pulse signals generated by the central processing unit are transmitted in the detection cable after being amplified by the driving circuit, and when the cable is broken due to collapse, the pulse signals are reflected back and received by the receiver, and after being processed, the pulse signals are transmitted to the detection cable. According to the device for detecting the road surface collapse position based on the time domain reflection method and the detection method, the data processing process is simple, the detection precision is high, real-time detection can be achieved, and the detection cost is greatly reduced.

Description

Technical Field

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

[0002] Road collapse is the process and phenomenon of a road sinking due to natural or human factors, forming depressions or potholes in the road surface. Detecting road collapse is a crucial measure for ensuring road safety and maintenance, especially on highways. Failure to promptly detect collapses can easily lead to major accidents. Prior art methods rely solely on road surface data for prediction and warning. For example, patent publication number CN113325419B discloses a road collapse detection method that combines L-band InSAR satellite radar with dual-frequency, high-dynamic ground-penetrating radar (GPR). This method can quickly and accurately analyze underground hidden dangers, providing a basis for rapid early warning and quantitative remediation of road safety hazards. However, the following problems remain: While only providing an early warning function, it cannot detect collapses, and data processing is complex, resulting in high equipment costs. Furthermore, due to the long distances of highways, regular GPR detection is labor-intensive, and it is difficult to balance detection costs with frequency. Summary of the Invention

[0003] The purpose of the present invention is to provide a device and a method for detecting the location of road collapse based on time domain reflectometry to solve the above technical problems.

[0004] To achieve the above object, the present invention provides a device for detecting the location of road collapse based on time domain reflectometry, comprising a central processing unit, A central processing unit is used to generate pulse signals and calculate collapse positions; the central processing unit is connected to a timer; The central processing unit is connected to a detection cable via a driving circuit, and the driving circuit is used to amplify the pulse signal; The detection cable is laid along the detection road surface to amplify the propagation of the pulse signal; The receiver is connected to the central processing unit through the data processing circuit. The receiver is used to capture the reflected signal of the pulse signal propagating along the detection cable when it encounters a breakpoint; The data processing circuit receives the reflected signal, processes and calculates the data, and then transmits it to the central processing unit.

[0005] Preferably, the receiver is an analog-to-digital conversion module or a TDR receiver.

[0006] Preferably, the data processing circuit includes 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 sending a pulse and receiving a reflected signal.

[0007] Preferably, the edge detection module includes a second-order derivative calculation submodule and a threshold calculation submodule, and both the second-order derivative calculation submodule and the threshold calculation submodule are connected to the filtering module. When the reflection signal calculated by the second-order 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 to be the starting point.

[0008] Preferably, the detection cable is laid in the detection pavement through a support tube, the support tube includes a number of connection units, the connection units include a symmetrically arranged upper tube segment and a lower tube segment, the upper tube segment is 8cm-10cm away from the top of the detection pavement, the lower tube segment is provided with a through hole and an arc-shaped protective plate is provided in the lower tube segment, 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 tube segment and the arc-shaped protective plate, the arc-shaped protective plate is used to separate the detection wire and the connecting wire, and the connecting wire is connected to the central processing unit through a demodulator.

[0009] Preferably, the central processing unit is arranged on the guardrail of the detection road surface and is electrically connected to the photovoltaic power generation and energy storage device, and the central processing unit is connected to a display.

[0010] A detection method for a device for detecting a road collapse location based on time domain reflectometry, comprising the following steps: Step S1: laying detection cables and arranging optical fiber humidity sensors on the detection road surface; Step S2: The central processing unit collects the humidity signal of the demodulator in real time. When the humidity reaches the first warning value, the central processing unit generates a pulse signal and amplifies it through the driving circuit. The amplified pulse signal propagates along the detection cable. The receiver receives the reflected signal and removes high-frequency noise and interference through the data processing circuit. The edge detection module then calculates the position of the starting point and the time difference between sending the pulse and receiving the reflected signal. The position of the reflection point is calculated based on the time difference. If the reflection point is within the mileage of the detected road surface, it is determined to be a break point. If the reflection point is at the end point of the detected road surface, it is determined that the road surface has not been broken. Or the central processor generates a pulse signal within a set interval, which is amplified by the driving circuit, propagated, reflected, received and data processed in the detection cable in sequence. The edge detection module calculates the position of the starting point and the time difference between sending the pulse and receiving the reflected signal. The position of the reflection point is calculated based on the time difference. If the reflection point is within the mileage of the detected road surface, it is determined that the reflection point is a break point. If the reflection point is at the end point of the detected road surface, it is determined that the road surface has not been broken.

[0011] Preferably, in step S1, at least one paving groove of a set height is opened on each lane of the detection road surface, linearly distributed detection holes are opened in the paving groove, and optical fiber humidity sensors are set in the detection holes. The optical fiber humidity sensor passes through the lower pipe segment in the paving groove and is connected to the demodulator. After the detection cable is placed in the lower pipe segment, the upper pipe segment is installed and the road surface is leveled by filling with asphalt.

[0012] Preferably, in step S1, a detection hole is set before the detection road surface is paved, and a fiber optic humidity sensor is set in the detection hole. The fiber optic humidity sensor passes through the lower pipe segment in the paving groove and is connected to the demodulator. After the detection cable is placed in the lower pipe segment, the upper pipe segment is installed, and the support tube is supported by the support member to set the height, the detection road surface is paved.

[0013] Preferably, the calculation formula for calculating the reflection point position based on the time difference is as follows: ; Where D is the distance between the reflection point and the starting point, is the time difference, is the signal propagation speed related to the dielectric constant of the cable.

[0014] Therefore, the present invention adopts the above-mentioned device and method for detecting the location of road collapse based on time domain reflectometry, which has the following beneficial effects: By measuring the time difference between the pulse's transmission and its reflection, the specific location of the reflection point is calculated, thereby identifying the road collapse point. This simplifies data processing, achieves high detection accuracy, and enables real-time detection, significantly reducing detection costs. A fiber-optic humidity sensor also monitors the humidity beneath the road surface in real time, triggering the collapse detection process. This reduces detection energy consumption and test frequency, while ensuring detection accuracy.

[0015] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a principle block diagram of a device for detecting road collapse locations based on time domain reflectometry according to the present invention; Figure 2 This is a structural diagram of the detection cable of the present invention being set on the detection road surface.

[0017] Reference numerals 1. Detection road surface; 2. Detection cable; 3. Upper tube segment; 4. Lower tube segment; 5. Curved guard plate; 6. Fiber optic humidity sensor. DETAILED DESCRIPTION

[0018] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the inventive product is usually placed when in use. These are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. In the description of the present invention, it should also be noted that, unless otherwise expressly specified and limited, the terms "setting", "installation" and "connection" 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 a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Example 1 like Figure 1 As shown, a device for detecting the collapse position of a road surface 1 based on time domain reflection method includes a central processing unit, a driving circuit, a detection cable 2, a receiver and a data processing circuit.

[0021] The detection road surface 1 of this embodiment is 1 kilometer long (the devices are superimposed according to actual needs), and the detection cable 2 is a coaxial cable.

[0022] The central processing unit adopts STM32 microcontroller, which is used to generate pulse signals and calculate the collapse position. The central processing unit is connected to a timer, which adopts a high-precision timer to ensure the accuracy of the measurement.

[0023] The central processing unit is connected to a detection cable 2 via a driver circuit. This driver circuit is used to amplify the pulse signal. This embodiment uses a 50Hz sampling rate to capture reflected signals within the chassis, ensuring the integrity of signal details. The detection cable 2 is laid along the detection surface 1 to propagate the amplified pulse signal. This embodiment uses a high-power driver circuit; low- and medium-power driver circuits can be used for shorter-range detection surfaces 1.

[0024] The receiver is connected to the central processing unit (CPU) via a data processing circuit. In this embodiment, the receiver is an analog-to-digital conversion module, which captures the reflected signal from the pulse signal propagating along the detection cable 2 and encountering a breakpoint. The data processing circuit receives the reflected signal, processes and calculates the data, and then transmits it to the CPU. The data processing circuit includes a filtering module, which removes high-frequency noise and interference; an edge detection module, which determines the starting point of the reflected signal; and a time difference calculation module, which calculates the time difference between the transmitted pulse and the received reflected signal.

[0025] The edge detection module includes a second-order derivative calculation submodule and a threshold calculation submodule. Both the second-order derivative calculation submodule and the threshold calculation submodule are connected to the filtering module. When the reflection signal calculated by the second-order 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 two edge algorithms are combined to improve the accuracy of edge detection.

[0026] In order to facilitate the subsequent replacement of the detection cable 2, the detection cable 2 is laid in the detection road surface 1 through a support tube, such as Figure 2 As shown, the support tube includes several connecting units, each of which includes an upper tube sheet 3 and a lower tube sheet 4 that are symmetrically arranged. Figure 2 The height of the middle H is 8 cm to 10 cm between the upper tube segment 3 and the top of the detection road surface 1. A through hole is opened in the lower tube segment 4 and an arc-shaped guard plate 5 is provided in the lower tube segment 4. The optical fiber humidity sensor 6 passes through the through hole and is arranged below the detection road surface 1. The connecting wire of the optical fiber humidity sensor 6 is arranged between the lower tube segment 4 and the arc-shaped guard plate 5. The arc-shaped guard plate 5 is used to separate the detection wire and the connecting wire. The connecting wire is connected to the central processing unit through a demodulator.

[0027] The central processing unit is arranged on the guardrail of the detection road surface 1 and is electrically connected to the photovoltaic power generation and energy storage device for providing electric energy. The central processing unit is connected to a display for displaying the detection results.

[0028] The detection method of the device for detecting the collapse position of the road surface 1 based on the time domain reflectometry method has the following specific steps: Step S1: Laying a detection cable 2 and arranging an optical fiber humidity sensor 6 on a detection road surface 1.

[0029] In this embodiment, paving is carried out on the existing road surface, and at least one paving groove of a set height is opened on each lane of the detection road surface 1. Linearly distributed detection holes are opened in the paving groove, and an optical fiber humidity sensor 6 is set in the detection hole. The optical fiber humidity sensor 6 passes through the lower pipe segment 4 in the paving groove and is connected to the demodulator. After the detection cable 2 is placed in the lower pipe segment 4, the upper pipe segment 3 is installed, and then the road surface is leveled by asphalt filling.

[0030] Step S2: The central processing unit collects the humidity signal of the demodulator in real time. When the humidity reaches the first warning value, the central processing unit 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 and removes high-frequency noise and interference through the data processing circuit. The edge detection module then calculates the position of the starting point and the time difference between sending the pulse and receiving the reflected signal. The reflection point position is calculated based on the time difference. The calculation formula for calculating the reflection point position based on the time difference is as follows: ; Where D is the distance between the reflection point and the starting point, is the time difference, = is the signal propagation speed related to the cable's dielectric constant. If the reflection point is within the mileage of the test road surface 1, it is considered a break point. If the reflection point is at the end point of the test road surface 1, it is considered that the road surface has not been broken.

[0031] In order to verify the reliability of this method, a breakpoint was set at 100 meters. The speed is 200 m / μs. Multiple tests were carried out and the obtained data are shown in Table 1 below.

[0032] Table 1 Test data ;

[0033] The error is within 0.2 meters, meeting the needs of short-distance precise detection.

[0034] Example 2 The difference between this embodiment and embodiment 1 is that step S1 is different. This embodiment performs the setting when detecting the paving of the road surface 1. The specific process is as follows: Before the detection pavement 1 is paved, a detection hole is set, and a fiber optic humidity sensor 6 is set in the detection hole. The fiber optic humidity sensor 6 passes through the lower pipe segment 4 in the paving groove and is connected to the demodulator. After the detection cable 2 is placed in the lower pipe segment 4, the upper pipe segment 3 is installed, and the support tube is supported by the support member to set the height, the detection pavement 1 is paved.

[0035] Example 3 The difference between this embodiment and embodiment 1 is that the collapse detection method is different. This embodiment uses a central processing unit to generate a pulse signal within a set interval for collapse detection, and the pulse signal is amplified by the driving circuit, propagated, reflected, received and data processed in the detection cable 2 in sequence. The edge detection module calculates the position of the starting point and the time difference between sending the pulse and receiving the reflected signal. The position of the reflection point is calculated based on the time difference. If the reflection point is within the mileage of the detection road surface 1, the reflection point is determined to be a fracture point. If the reflection point is at the end point of the detection road surface 1, it is determined that the road surface has not been fractured.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

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: A central processing unit is used to generate pulse signals and calculate collapse positions; the central processing unit is connected to a timer; The central processing unit is connected to a detection cable via a driving circuit, and the driving circuit is used to amplify the pulse signal; The detection cable is laid along the detection road surface to amplify the propagation of the pulse signal; The receiver is connected to the central processing unit through the data processing circuit. The receiver is used to capture the reflected signal of the pulse signal propagating along the detection cable when it encounters a breakpoint; The data processing circuit receives the reflected signal, processes and calculates the data, and then transmits it to the central processing unit.

2. The device for detecting road collapse locations based on time domain reflectometry according to claim 1, characterized in that: The receiver is an analog-to-digital conversion module or a TDR receiver.

3. The device for detecting road collapse locations based on time domain reflectometry according to claim 2, characterized in that: The data processing circuit includes 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 sending a pulse and receiving a reflected signal.

4. The device for detecting road collapse locations based on time domain reflectometry according to claim 3, characterized in that: The edge detection module includes a second-order derivative calculation submodule and a threshold calculation submodule. Both the second-order derivative calculation submodule and the threshold calculation submodule are connected to the filtering module. When the reflection signal calculated by the second-order 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 to be the starting point.

5. The device for detecting road collapse locations based on time domain reflectometry according to claim 4, characterized in that: The detection cable is laid in the detection pavement through a support tube. The support tube includes several connection units. The connection units include symmetrically arranged upper and lower tube segments. The upper tube segment is 8cm-10cm away from the top of the detection pavement. The lower tube segment is provided with a through hole and an arc-shaped protective plate is provided in the lower tube segment. 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 tube segment and the arc-shaped protective plate. The arc-shaped protective plate is used to separate the detection wire and the connecting wire. The connecting wire is connected to the central processing unit through a demodulator.

6. The device for detecting road collapse locations based on time domain reflectometry according to claim 5, characterized in that: The central processing unit is arranged on the guardrail of the detection road surface and is electrically connected to the photovoltaic power generation and energy storage device. The central processing unit is connected to a display.

7. The detection method of the device for detecting the location of a road collapse based on time domain reflectometry according to claim 6, characterized in that: The specific steps are as follows: Step S1: laying detection cables and arranging optical fiber humidity sensors on the detection road surface; Step S2: The central processing unit collects the humidity signal of the demodulator in real time. When the humidity reaches the first warning value, the central processing unit generates a pulse signal and amplifies it through the driving circuit. The amplified pulse signal propagates along the detection cable. The receiver receives the reflected signal and removes high-frequency noise and interference through the data processing circuit. The edge detection module then calculates the position of the starting point and the time difference between sending the pulse and receiving the reflected signal. The position of the reflection point is calculated based on the time difference. If the reflection point is within the mileage of the detected road surface, it is determined to be a break point. If the reflection point is at the end point of the detected road surface, it is determined that the road surface has not been broken. Or the central processor generates a pulse signal within a set interval, which is amplified by the driving circuit, propagated, reflected, received and data processed in the detection cable in sequence. The edge detection module calculates the position of the starting point and the time difference between sending the pulse and receiving the reflected signal. The position of the reflection point is calculated based on the time difference. If the reflection point is within the mileage of the detected road surface, it is determined that the reflection point is a break point. If the reflection point is at the end point of the detected road surface, it is determined that the road surface has not been broken.

8. The detection method of the device for detecting the location of a road collapse based on time domain reflectometry according to claim 7, characterized in that: In step S1, at least one paving groove of a set height is opened on each lane of the detection road surface, and linearly distributed detection holes are opened in the paving groove. Fiber optic humidity sensors are set in the detection holes. The fiber optic humidity sensors pass through the lower pipe segment in the paving groove and are connected to the demodulator. After the detection cable is placed in the lower pipe segment, the upper pipe segment is installed, and then the road surface is leveled by asphalt filling.

9. The detection method of the device for detecting the location of a road collapse based on time domain reflectometry according to claim 7, characterized in that: In step S1, a detection hole is set before the detection road surface is paved, and a fiber optic humidity sensor is set in the detection hole. The fiber optic humidity sensor passes through the lower pipe segment in the paving groove and is connected to the demodulator. After the detection cable is placed in the lower pipe segment, the upper pipe segment is installed, and the support tube is supported by the support member to set the height, the detection road surface is paved.

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

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