Operation period diversion tunnel surrounding rock deformation monitoring system based on millimeter wave radar

Abstract

The utility model discloses an operation period diversion tunnel surrounding rock deformation monitoring system based on millimeter wave radar, which comprises a remote monitor, a plurality of mounting supports, a plurality of radar assemblies and a plurality of corner reflectors, and is characterized in that the radar assemblies are used for receiving reflection signals of the corner reflectors and sending the reflection signals to the remote monitor through wireless signals; the corner reflector is fixedly mounted in surrounding rock of the diversion tunnel; the installation support is fixedly installed on the wall of the diversion tunnel, and the radar assembly is installed on the installation support. According to the utility model, through cooperation of the radar assembly and the corner reflector, high-precision and stable monitoring which is not influenced by signal shielding and a humid environment in a hole is realized, multiple targets can be accurately and simultaneously monitored, and the working efficiency is improved; the system supports remote monitoring and data analysis, a worker can obtain latest monitoring information in real time at a place far away from a site, potential safety hazards can be found in time, and support is provided for scientific decision making.

Description

TECHNICAL FIELD

[0001] The utility model relates to water diversion tunnel surrounding rock deformation monitoring technical field, concretely relates to a kind of water diversion tunnel surrounding rock deformation monitoring system based on millimeter wave radar in operating period. BACKGROUND

[0002] Water diversion tunnel is a kind of water diversion tunnel from water source, mainly used to water from a water source to the required site. It can take water from reservoir, river or lake, cross mountain to meet various needs, including power generation, farmland irrigation, navigation, water or urban industrial, domestic water, etc.

[0003] At present, in domestic and foreign water diversion projects, due to the limitation of topographic conditions, long tunnel has become the inevitable choice of water conveyance, and in the trans-regional large-scale water diversion projects that have been built and are under construction, the water diversion projects that use super-long tunnel include Shanxi Province Yellow River into Shanxi Project, Liaoning Province East Water West Diversion Project and Shaanxi Province Han River to Wei River Project. As a typical building in water diversion project, due to the complexity of its length, depth and geological conditions, it is difficult to monitor it by conventional means.

[0004] Water diversion tunnel has the following two characteristics compared with ordinary tunnel:

[0005] (1) there is internal water action

[0006] Water diversion tunnel is divided into pressure tunnel and non-pressure tunnel. The tunnel using pressure water usually needs to bear large internal water pressure during operation, while the tunnel using non-pressure water is affected by seasonal changes and bears water flow replacement changes.

[0007] (2) long distribution length

[0008] Water diversion project usually presents linear, and its spanning region can reach hundreds of kilometers, and needs to face various complex topography and geological structure, cross natural topography and geomorphology such as mountains and rivers, and may cross ground buildings such as roads and railways.

[0009] Due to the importance of water diversion tunnel and the severity of the problem, the management and operation unit will regularly detect and monitor the surrounding rock deformation. But due to the long length of water diversion tunnel and the poor internal environment, traditional methods face the following problems:

[0010] (1) In-situ monitoring using sensors such as hydrostatic level instruments. Since water diversion tunnels are generally long, using wired transmission for deformation monitoring would result in high transmission line costs, while using wireless transmission technology would result in problems such as wireless transmission signal shielding. In addition, the presence of water in water diversion tunnels makes the internal environment humid, and the monitoring sensors are prone to failure due to moisture. Therefore, this method is difficult to use for a long time, or the sensors and lines need to be replaced during long-term use, resulting in excessively high monitoring costs.

[0011] (2) Monitoring is carried out using optical equipment such as total stations. This method is currently the most commonly used method, but for water diversion tunnels, the accuracy of this method decreases sharply over long distances and is easily affected by dust, water vapor and other factors in the tunnel. Therefore, it is also difficult to use for monitoring the deformation of the surrounding rock in water diversion tunnels.

[0012] (3) Image measurement method. The image measurement method uses cameras to take pictures of the target periodically and uses image recognition technology to calculate the target deformation. Because the environment inside the water diversion tunnel is relatively humid, it affects the focusing of the shooting equipment, so the accuracy of this type of method is affected when applied to the deformation monitoring of the water diversion tunnel.

[0013] (4) Using satellite positioning systems. This method has the advantage of a large measurement range, is not affected by sunlight, rain, fog, or dust, and can be used around the clock. However, the deformation measurement of the surrounding rock of the water diversion tunnel needs to be carried out inside the tunnel, which has a certain shielding effect on satellite signals. Moreover, the monitoring accuracy of this method is not high, and its application in the deformation monitoring of water diversion tunnels during operation has certain limitations.

[0014] Therefore, there is currently no good deformation monitoring method for water diversion tunnels in operation due to the complex environment inside the tunnels, and there is an urgent need to improve the existing monitoring methods. Utility Model Content

[0015] To address the shortcomings of poor signal and susceptibility to the influence of the tunnel environment in monitoring surrounding rock deformation in water diversion tunnels during operation, this utility model provides a millimeter-wave radar-based system for monitoring surrounding rock deformation in long-distance water diversion tunnels. This system is unaffected by signal shielding or the tunnel environment and can simultaneously monitor multiple targets.

[0016] To achieve the above objectives, the technical solution of this utility model is as follows:

[0017] The application discloses a millimeter wave radar-based operation period surrounding rock deformation monitoring system for diversion tunnel, which comprises a remote monitor and a plurality of installation supports, radar components and corner reflectors, wherein the radar components are used for receiving reflected signals of the corner reflectors and transmitting the reflected signals to the remote monitor through wireless signals; the corner reflectors are fixedly installed in surrounding rocks of the diversion tunnel; and the installation supports are fixedly installed on walls of the diversion tunnel, and the radar components are installed on the installation supports.

[0018] Further, the corner reflector is composed of three mutually perpendicular plane mirrors to form a triangular pyramid structure, and an outer side of one of the plane mirrors is additionally provided with a connecting mechanism. In use, the connecting mechanism is fixedly installed at a measuring point position, at which time the triangular pyramid structure is arranged in an inverted triangular shape; the corner reflector adopting the triangular pyramid structure enhances the strength and stability of the reflected signals, and ensures that the radar components can accurately receive the reflected signals; and the structure is particularly suitable for the relatively harsh working environment of the diversion tunnel, and can ensure long-term stable monitoring performance.

[0019] Further, the connecting mechanism is a steel bar. The steel bar has high strength and corrosion resistance, can adapt to complex geological conditions, provides a stable installation basis in use, ensures that the corner reflector can be stably and reliably installed under various environmental conditions, and thus ensures the accuracy of the measurement data; in addition, the flexibility of the steel bar allows it to adjust the length and shape according to actual needs, simplifies the installation process, improves the construction efficiency, and the steel bar has low cost, is easy to purchase, and is convenient for production and processing of the corner reflector.

[0020] Further, the connecting mechanism is a bolt. Compared with the steel bar, the bolt is used as the connecting mechanism, the connection is more stable and reliable, not only provides a high-precision and stable installation mode, but also the bolt connection mode is convenient for disassembly and repositioning, so that the operation is simple and fast when the monitoring point needs to be adjusted or maintained, without the need for complex tools or techniques, thereby reducing the installation and maintenance costs.

[0021] Further, the connecting mechanism comprises an embedding rod and a connecting rod; an upper segment of the embedding rod is an anchor head structure, and a lower segment of the embedding rod is a threaded rod; the connecting rod is fixedly connected with the plane mirror at the bottom and provided with a threaded connection sleeve at the top. In use, the embedding rod is first fixedly installed at a measuring point position, and then the connecting rod is rotated and installed in the threaded rod of the embedding rod to complete the connection of the corner reflector; the separable design of the embedding rod and the connecting rod of the corner reflector facilitates the installation of the corner reflector and the subsequent maintenance and maintenance operation of the corner reflector; the anchor head structure of the embedding rod ensures that the embedding rod can be firmly anchored in the surrounding rock under complex geological conditions; the threaded connection mode not only simplifies the installation process, but also facilitates the disassembly of the connecting rod; and the step-by-step installation method effectively reduces the cumulative error, ensures that each corner reflector can accurately correspond to a predetermined monitoring point, and improves the overall measurement accuracy.

[0022] Further, the radar assembly comprises a radar, a data collector and a signal transceiver, wherein the radar is installed on a mounting bracket; the data collector is connected with the radar and the signal transceiver through data lines respectively. In use, the radar emits a high-frequency electromagnetic wave, usually a microwave or a millimeter wave. The electromagnetic wave propagates in the air until it is reflected by the surface of the corner reflector. Part of the reflected electromagnetic wave is captured by the radar assembly and collected by the data collector. The collected data is transmitted to the signal transceiver, which sends the data to the remote monitor. The remote monitor analyzes and displays the deformation condition of the surrounding rock. The radar is installed on a stable mounting bracket to ensure that it can stably emit high-frequency electromagnetic waves. The connected data collector can ensure that the information is accurately transmitted to the signal transceiver. The signal transceiver transmits the data to the remote monitor in real time through wireless transmission technology, so that the manager can analyze and display the deformation condition of the surrounding rock in real time at a location away from the site. The signal transceiver can be arranged outside the surrounding rock of the diversion tunnel. This arrangement can effectively avoid the problem of data loss caused by signal shielding in the diversion tunnel and facilitate efficient and accurate data transmission.

[0023] Further, the remote monitor comprises a CPU processor, a signal receiver and a display, wherein the CPU processor is connected with the signal receiver and the display respectively, and the signal receiver transmits the received signal to the CPU processor for processing and calculation. The signal receiver can stably receive the wireless transmission data from the radar assembly and quickly transmit these raw data to the CPU processor. The CPU processor has strong computing power and can process and analyze a large amount of monitoring data in real time, quickly identify the trend of surrounding rock deformation, and effectively ensure the accuracy and timeliness of data analysis. The processed data is then transmitted to the display to present to the operator in an intuitive form, so that the manager can understand the deformation condition of the surrounding rock in the first time and take necessary measures in time.

[0024] Installation method:

[0025] The remote monitor is installed in a remote monitoring room. When installing the radar assembly and the corner reflector, first determine the deformation monitoring section of the tunnel. The specific deformation monitoring section needs to be set according to the geological conditions and other conditions of the diversion tunnel location. The principles for setting the deformation monitoring section are as follows: ① Along the full length of the diversion tunnel; ② Increase the monitoring section at the location crossing different geological environments.

[0026] Subsequently, preliminary survey points are arranged at the deformation monitoring section location. For a portal-type diversion tunnel, the survey points are usually arranged at the crown, 1 / 4 arch and arch foot positions. For a circular tunnel, the survey points are usually arranged at the top, 1 / 4 of the upper half circle and the position of the circle half.

[0027] After the determination of the measuring points, the monitoring maximum distance is calculated according to the relevant parameters of the radar component, and then the installation support is arranged according to the distance, wherein it is also required to ensure that the measuring points are not blocked and the minimum distance between the measuring points is greater than the minimum resolution distance of the radar, and when it cannot be met, the measuring point position is adjusted appropriately;

[0028] The corner reflector is installed at the finally determined measuring point position, and the measuring point installation is completed, and finally the radar component is placed on the installation support, the radar component is set with appropriate sampling frequency and frequency modulation bandwidth to ensure that all measuring points can be effectively covered in the scanning process, and the measuring points between several stations can simultaneously perform multi-target monitoring.

[0029] Monitoring principle and method:

[0030] The millimeter wave radar calculates the deformation between the reference point and the target point by comparing the phase difference between the transmitted signal s0(t) and the reflected signal s R (t), as follows:

[0031] Transmitted signal:

[0032] Reflected signal:

[0033] In the initial state, the distance from the radar to the monitoring point is D1, and when the monitoring point deforms, the distance from the radar to the monitoring point is D2. When the radar performs the first observation, the phase is When the tunnel surrounding rock measuring point deforms, the observed phase at this time is Deformation

[0034] During detection, according to the shape and stress characteristics of the diversion tunnel section, monitoring points are set at key point positions of the monitoring section. The corner reflector for reflection is installed at the measuring point position by embedding steel bars or bolts. In order to ensure that the corner reflector and the monitoring point deform synchronously, the embedded steel bars or bolts have a diameter of not less than 18 mm and have a certain rigidity.

[0035] The station position is set according to the maximum distance that can be monitored by the equipment.

[0036] The millimeter wave radar signal is transmitted through the transmitting antenna (TX), and the expression of the transmitted signal is:

[0037]

[0038] In the formula, A e is the radar antenna gain, f c is the starting frequency of the radar signal, S is the frequency modulation slope of the signal, t is the duration of the signal, is the initial phase of the signal.

[0039] The radar wave reaches the monitoring point, and the reflected wave is received by the receiving antenna (RX) after the angle reflection of the monitored point. The expression of the reflected wave signal is:

[0040]

[0041] In the formula, τ is the double-path time delay of the distance between the radar and the monitoring point, D0 is the distance between the radar and the target point, and c is the speed of light.

[0042] The mixer mixes the transmitted signal and the reflected signal to generate an IF signal with a specific frequency. The expression of the IF signal is as follows:

[0043] s IF (t)=s t (t)×s * (t)=Aexp{j2πf c [t-(t-τ)]+jπS[t 2 -(t-τ) 2 ]}

[0044] The above formula is simplified and rewritten as:

[0045]

[0046] In the formula,

[0047] The final intermediate frequency signal can be expressed as:

[0048] s IF (t)=Aexp{j2πStτ+j2πf c τ}

[0049] The Fourier transform of the above signal is performed, and the peak frequency in the frequency domain is the frequency of the intermediate frequency signal. The frequency of the intermediate frequency signal is Bτ / T, and the phase is 2πf c τ. Then the distance from the radar to the monitoring point can be solved from the frequency of the intermediate frequency signal, and the relationship between them is:

[0050]

[0051] In the formula, D0 is the distance between the radar and the monitoring point, f IF is the frequency peak value of the intermediate frequency signal in the frequency domain.

[0052] Finally, the distance from the radar to the monitoring point can be obtained as:

[0053]

[0054] The maximum monitoring distance of the millimeter radar wave is:

[0055]

[0056] Since the frequency of the intermediate frequency signal must be within the set sampling frequency, the target can be identified, which requires f IF ≤f s That is, the maximum monitoring distance of the millimeter wave radar is:

[0057]

[0058] Where f s is the sampling frequency of the millimeter wave radar, and c is the speed of light.

[0059] In the actual monitoring process, the setting interval L of the monitoring station should be less than or equal to 0.8D max to ensure the accuracy of the results.

[0060] Set appropriate sampling frequency and frequency modulation bandwidth to ensure that all measurement points can be effectively covered during scanning.

[0061] When monitoring multiple targets at the same time, if the distance between two monitoring points is too small, the radar system will not be able to distinguish the signals of the two targets, so the bandwidth of the radar frequency modulation signal needs to be set to correctly distinguish the monitoring points at different positions. The specific principle is as follows:

[0062] The frequency difference between multiple monitoring targets is:

[0063]

[0064] Where △D is the distance interval between adjacent targets.

[0065] According to the frequency spectrum, the frequency resolution is:

[0066]

[0067] The frequency difference between the two signals must be greater than 1 / T to distinguish the two monitoring points, that is, △f≥1 / T, and at this time:

[0068]

[0069] Finally, the resolution of the millimeter wave radar in distance is:

[0070]

[0071] Where B is the signal frequency modulation bandwidth.

[0072] In use, the radar assembly first emits a high-frequency electromagnetic wave, usually a microwave or millimeter wave, which propagates in the air until it is reflected by the corner reflector surface, part of the reflected electromagnetic wave is captured and collected by the radar assembly, and then the radar assembly also sends wireless signals to the remote monitor, the remote monitor can confirm the deformation condition of the surrounding rock of the diversion tunnel where the radar assembly is located by analyzing the individual radar assembly, and the remote monitor can also combine the return data of several radar assemblies to perform more comprehensive and specific deformation analysis on the surrounding rock of the entire diversion tunnel during operation, so that the staff can view the deformation condition of the surrounding rock through the remote monitor.

[0073] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0074] 1. The utility model discloses a combination of millimeter wave radar technology and corner reflector application, realizes high-precision, stable monitoring not affected by signal shielding and humid environment in the hole, can also accurately monitor multiple targets at the same time, greatly improves work efficiency and reduces data acquisition period, the system is easy to install and maintain, adopts wireless transmission mode to reduce wiring cost and complexity, and arranges deformation monitoring section according to different geological conditions, ensures the comprehensiveness and representativeness of monitoring data, in addition, the system supports remote monitoring and data analysis, and the staff can acquire the latest monitoring information in real time in the place far away from the scene, discovers potential safety hazards in time, and provides support for scientific decision-making.

[0075] 2. The corner reflector of the utility model is a three-prism structure, which enhances the strength and stability of the reflected signal, ensures that the radar assembly can accurately receive the reflected signal, and has a stable monitoring performance for a long time, the radar is stable, can stably emit high-frequency electromagnetic waves, the data collector transmits data to the signal transceiver, and the signal transceiver sends the remote monitor, and the manager can remotely view the deformation condition of the surrounding rock, the signal receiver can stably receive the wireless transmission data from the radar assembly, and a large amount of monitoring data can be processed and analyzed in real time after the data is delivered to the CPU processor, the trend of surrounding rock deformation can be quickly identified, and the accuracy and timeliness of data analysis can be effectively ensured.

[0076] 3.The connecting mechanism adopts steel bars to ensure that the corner reflector can remain stable and reliable under various environmental conditions, and the flexibility of the steel bars allows the length and shape to be adjusted according to actual needs, simplifying the installation process and improving the construction efficiency; the bolt connection of the connecting mechanism is more stable and reliable, not only providing a high-precision and stable installation method, but also facilitating disassembly and repositioning, so that the operation is simple and fast when the monitoring point needs to be adjusted or maintained; the connecting mechanism adopts an embedded rod and a connecting rod, the anchor head structure of the embedded rod ensures that it can be firmly anchored in the surrounding rock under complex geological conditions, and the threaded connection of the connecting rod not only simplifies the installation process, but also facilitates the disassembly of the connecting rod. BRIEF DESCRIPTION OF DRAWINGS

[0077] Figure 1 It is a transverse schematic view of the installation position of a door-hole type diversion tunnel of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0078] Figure 2 It is a longitudinal schematic view of the installation position of a radar assembly of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0079] Figure 3 It is a deformation measuring point layout diagram of a door-hole type diversion tunnel of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0080] Figure 4 It is a deformation monitoring schematic diagram of a radar assembly in a diversion tunnel of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0081] Figure 5 It is a deformation measuring point layout diagram of a circular type diversion tunnel of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0082] Figure 6 It is a structural schematic diagram of a corner reflector in Embodiment 4 of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0083] Figure 7 It is a structural schematic diagram of a corner reflector in Embodiment 5 of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0084] Figure 8 It is a structural schematic diagram of a corner reflector in Embodiment 6 of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0085] Figure 9 It is a ranging principle schematic diagram of a radar assembly of a millimeter wave radar-based deformation monitoring system for surrounding rock of a diversion tunnel in an operation period.

[0086] Attached image labels:

[0087] Remote monitor—1, mounting bracket—2, radar assembly—3, radar—31, data acquisition unit—32, signal transceiver—33, corner reflector—4, plane mirror—41, connecting mechanism—42, reinforcing bar—421, bolt—422, connecting rod—423, anchor head structure—424, threaded rod—425. Detailed Implementation

[0088] The present invention will be further described below with reference to the accompanying drawings.

[0089] Example 1: As Figure 1 As shown, an operational water diversion tunnel surrounding rock deformation monitoring system based on millimeter-wave radar includes a remote monitor 1, several mounting brackets 2, a radar assembly 3, and corner reflectors 4. The radar assembly 3 is used to receive the reflected signals from the corner reflectors 4 and transmit them to the remote monitor 1 via wireless signals. The corner reflectors 4 are fixedly installed in the surrounding rock of the water diversion tunnel. The mounting brackets 2 are fixedly installed on the wall of the water diversion tunnel, and the radar assembly 3 is mounted on the mounting brackets 2.

[0090] Installation method:

[0091] The remote monitor 1 is installed in a remote monitoring room. When installing the radar component 3 and the corner reflector 4, the deformation monitoring section of the tunnel is first determined. Specifically, the deformation monitoring section needs to be set according to the geological conditions and other conditions at the location of the water diversion tunnel. The setting principle of the deformation monitoring section is: ① to be arranged along the entire length of the water diversion tunnel; ② to increase the density of the monitoring section at the crossing of different geological environments.

[0092] Subsequently, preliminary measuring points were set up at the deformation monitoring section location, with reference to... Figure 3 For portal-type water diversion tunnels, measuring points are typically placed at the arch crown, quarter-arch, and arch foot; (Reference) Figure 6 For circular tunnels, measuring points are usually placed at the top, at the top quarter of the circle, and at the halfway point of the circle.

[0093] After determining the measurement points, the maximum monitoring distance is calculated based on the relevant parameters of the radar component 3. Then, the mounting bracket 2 is arranged according to this distance. It is also necessary to ensure that the measurement points are unobstructed and that the minimum distance between the measurement points is greater than the minimum resolution distance of the radar 31. If these conditions cannot be met, the position of the measurement points is adjusted appropriately.

[0094] Angle reflector 4 is installed at the final determined measurement point location, thus completing the measurement point installation. Finally, radar component 3 is placed on mounting bracket 2. Radar component 3 is set with appropriate sampling frequency and frequency modulation bandwidth to ensure that all measurement points can be effectively covered during the scanning process, and multiple targets can be monitored simultaneously between measurement points of several stations.

[0095] In use, the radar assembly 3 first emits a high-frequency electromagnetic wave, usually a microwave or millimeter wave, which propagates in the air until it is reflected by the surface of the corner reflector 4. Part of the reflected electromagnetic wave is captured by the radar assembly 3, which then sends the signal to the remote monitor 1. The remote monitor 1 can analyze the data from a single radar assembly 3 to determine the deformation of the surrounding rock of the diversion tunnel where the radar assembly 3 is located. The remote monitor 1 can also analyze the data from multiple radar assemblies 3 to determine the deformation of the surrounding rock of the entire diversion tunnel. The staff can view the deformation of the surrounding rock through the remote monitor 1.

[0096] In Example 2, the corner reflector 4 is a three-prism structure composed of three mutually perpendicular plane mirrors 41. One of the plane mirrors 41 has a connecting mechanism 42 on its outer side. In use, the connecting mechanism 42 is fixedly installed at the measurement point, and the three-prism structure is arranged in an inverted triangular shape. The three-prism corner reflector 4 enhances the strength and stability of the reflected signal, ensuring that the radar assembly 3 can accurately receive the reflected signal. This structure is particularly suitable for harsh environments such as diversion tunnels and can ensure long-term stable monitoring performance.

[0097] The radar assembly 3 includes a radar 31, a data collector 32, and a signal transceiver 33. The radar 31 is installed on the mounting bracket 2. The data collector 32 is connected to the radar 31 and the signal transceiver 33 through data lines. In use, the radar 31 emits a high-frequency electromagnetic wave, usually a microwave or millimeter wave, which propagates in the air until it is reflected by the surface of the corner reflector 4. Part of the reflected electromagnetic wave is captured by the radar assembly 3 and collected by the data collector 32. The collected data is transmitted to the signal transceiver 33, which sends the data to the remote monitor 1 for analysis and display of the surrounding rock deformation. The radar 31 is installed on a stable mounting bracket 2 to ensure stable emission of high-frequency electromagnetic waves. The connected data collector 32 ensures accurate transmission of information to the signal transceiver 33. The signal transceiver 33 transmits data in real time to the remote monitor 1 through wireless transmission technology, allowing management personnel to analyze and display the surrounding rock deformation in real time from a remote location. The signal transceiver 33 can be placed on the outside of the diversion tunnel surrounding rock. This arrangement can effectively avoid data loss caused by signal blocking in the diversion tunnel and facilitate efficient and accurate data transmission.

[0098] Embodiment 3: Different from embodiment 2, the remote monitor 1 comprises a CPU processor, a signal receiver and a display, wherein the CPU processor is connected with the signal receiver and the display respectively, and the signal receiver transmits the received signals to the CPU processor for processing and calculation. The signal receiver can stably receive the wireless transmission data from the radar assembly 3 and quickly transmit the raw data to the CPU processor. The CPU processor has strong computing power and can process and analyze a large amount of monitoring data in real time, quickly identify the trend of surrounding rock deformation, effectively ensure the accuracy and timeliness of data analysis, and then transmit the processed data to the display to present to the operator in an intuitive form, so that the manager can understand the deformation condition of the surrounding rock in the first time and take necessary measures in time.

[0099] Embodiment 4: Different from embodiment 3, the connecting mechanism 42 is a steel bar 421. The steel bar 421 has high strength and corrosion resistance, can adapt to complex geological conditions, provides a stable installation foundation when used, ensures that the corner reflector 4 can maintain stable and reliable installation under various environmental conditions, thereby ensuring the accuracy of the measurement data; in addition, the flexibility of the steel bar 421 allows it to adjust the length and shape according to actual needs, simplifies the installation process, improves the construction efficiency, and the steel bar 421 has low cost, easy to purchase, and is convenient for the production and processing of the corner reflector 4. The diameter of the steel bar 421 is greater than or equal to 18 mm.

[0100] Embodiment 5: Different from embodiment 3, the connecting mechanism 42 is a bolt 422. Compared with the steel bar 421, the bolt 422 is used as the connecting mechanism 42, the connection is more stable and reliable, not only provides a high-precision and stable installation method, but also the bolt 422 connection method is convenient for disassembly and repositioning, so that the operation is simple and fast when the monitoring point needs to be adjusted or maintained, without the need for complex tools or technology, reducing the installation and maintenance cost. The diameter of the bolt 422 is greater than or equal to 18 mm.

[0101] Example 6: Different from example 3, the connecting mechanism 42 comprises an embedded rod and a connecting rod 423; the upper segment of the embedded rod is an anchor head structure 424, and the lower segment is a threaded rod 425; the bottom of the connecting rod 423 is fixedly connected with the plane mirror 41, and the top is a threaded connection sleeve matched with the threaded rod 425. In use, the embedded rod is first fixedly installed at the measurement point position, and then the connecting rod 423 is rotated and installed into the threaded rod 425 of the embedded rod to complete the connection of the corner reflector 4; the separable design of the embedded rod and the connecting rod 423 of the corner reflector 4 facilitates the installation of the corner reflector 4 and the subsequent maintenance and maintenance operation of the corner reflector 4; the anchor head structure 424 of the embedded rod ensures that it can be firmly anchored in the surrounding rock under complex geological conditions, and the threaded connection method not only simplifies the installation process, but also facilitates the disassembly of the connecting rod 423, and the step-by-step installation method effectively reduces the cumulative error, ensuring that each corner reflector 4 can accurately correspond to the predetermined monitoring point, improving the overall measurement accuracy.

[0102] The monitoring principle in the example is as follows:

[0103] As Figure 9 shown in FIG. 6, the millimeter wave radar 31 calculates the deformation between the reference point and the target point by comparing the phase difference between the transmitted signal s0(t) and the reflected signal s R (t). Specifically, the following steps are taken:

[0104] Transmitted signal:

[0105] Reflected signal:

[0106] In the initial state, the distance from the radar 31 to the monitoring point is D1, and when the monitoring point deforms, the distance from the radar 31 to the monitoring point is D2. When the radar 31 performs the first observation, the phase is When the tunnel surrounding rock monitoring point deforms, the observed phase at this time is Deformation

[0107] During detection, monitoring points are set at key positions on the monitoring section according to the shape and stress characteristics of the diversion tunnel section, and corner reflectors 4 are installed at the measurement point positions.

[0108] The measurement station position is set according to the maximum distance that can be monitored by the equipment.

[0109] The millimeter wave radar 31 signal is transmitted by the transmitting antenna TX, and the expression of the transmitted signal is:

[0110]

[0111] In the formula, A e is the antenna gain of the radar 31, f cis the initial frequency of the radar 31 signal, S is the frequency ramp of the signal, and t is the duration of the signal, is the initial phase of the signal.

[0112] The radar 31 wave reaches the monitoring point, is reflected by the monitoring point, and forms a reflected wave which is received by the receiving antenna RX. The expression of the reflected wave signal is:

[0113]

[0114] where τ is the double-path time delay of the distance between the radar 31 and the monitoring point, D0 is the distance between the radar 31 and the target point, and c is the speed of light.

[0115] The mixer mixes the transmitted signal and the reflected signal to generate an IF signal with a specific frequency. The expression of the IF signal is as follows:

[0116] s IF (t) = s t (t) × s * (t) = Aexp{j2πf c [t-(t-τ)]+jπS[t 2 -(t-τ) 2 ]}

[0117] After simplification and rewriting, the above expression is:

[0118]

[0119] where

[0120] The final IF signal can be expressed as:

[0121] s IF (t) = Aexp{j2πStτ+j2πf c τ}

[0122] The Fourier transform of the above signal is performed, and the peak frequency in the frequency domain is the frequency of the IF signal. The frequency of the IF signal is Bτ / T, and the phase is 2πf c τ. The distance from the radar 31 to the monitoring point can be solved from the frequency of the IF signal, and the relationship is:

[0123]

[0124] where D0 is the distance between the radar 31 and the monitoring point, and f IF is the frequency peak of the IF signal in the frequency domain.

[0125] Finally, the distance between the radar 31 and the monitoring point can be obtained as:

[0126]

[0127] The maximum monitoring distance of millimeter wave radar 31 wave:

[0128]

[0129] Since the frequency of the intermediate frequency signal must be within the set sampling frequency, the target can be identified, which requires f IF ≤f s , that is, the maximum monitoring distance of millimeter wave radar 31 is:

[0130]

[0131] Where f s is the sampling frequency set by the millimeter wave radar 31, and c is the speed of light.

[0132] In the actual monitoring process, the setting distance L of the monitoring station should be less than or equal to 0.8D max , to ensure the accuracy of the results.

[0133] Set the appropriate sampling frequency and frequency bandwidth to ensure that all measurement points can be effectively covered during scanning.

[0134] When monitoring multiple targets at the same time, if the distance between two monitoring points is too small, the radar 31 system will not be able to distinguish the signals of the two targets, so the bandwidth of the radar 31 frequency signal needs to be set to correctly distinguish the monitoring points at different positions. The specific principle is as follows:

[0135] The frequency difference between multiple monitoring targets is:

[0136]

[0137] In the formula, △D is the distance interval between adjacent targets.

[0138] According to the spectral properties, the frequency resolution is:

[0139]

[0140] The frequency difference between two signals must be greater than 1 / T to distinguish the two monitoring points, that is, △f≥1 / T, then:

[0141]

[0142] Finally, the resolution of millimeter wave radar 31 in distance is:

[0143]

[0144] In the formula, B is a signal frequency modulation bandwidth.

[0145] In the description of the present application, a large number of specific details are explained. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not shown in detail in order not to obscure the understanding of the present application.

[0146] Finally, it should be noted that: the above embodiments are used to illustrate the technical solutions of the present application, but not limited to them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A millimeter wave radar-based operating period of the diversion tunnel surrounding rock deformation monitoring system, characterized in that: The application relates to a remote monitoring device for a diversion tunnel, which comprises a remote monitor (1) and a plurality of mounting supports (2), radar assemblies (3) and corner reflectors (4), wherein the radar assemblies (3) are used for receiving reflected signals of the corner reflectors (4) and transmitting the signals to the remote monitor (1) through wireless signals; the corner reflectors (4) are fixedly installed in surrounding rocks of the diversion tunnel; the mounting supports (2) are fixedly installed on the wall of the diversion tunnel, and the radar assemblies (3) are installed on the mounting supports (2).

2. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to claim 1, characterized in that: The corner reflector (4) is composed of three mutually perpendicular plane mirrors (41) to form a triangular pyramid structure, and the outer side of one of the plane mirrors (41) is provided with a connecting mechanism (42).

3. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to claim 2, characterized in that: The connecting mechanism (42) is a reinforcing steel bar (421).

4. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to claim 2, characterized in that: The connecting mechanism (42) is a bolt (422).

5. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to claim 2, characterized in that: The connecting mechanism (42) comprises an embedding rod and a connecting rod (423); the upper segment of the embedding rod is an anchor head structure (424), and the lower segment is a threaded rod (425); the connecting rod (423) is fixedly connected with the plane mirror (41) at the bottom and is provided with a threaded connection sleeve at the top for matching the threaded rod (425).

6. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to any one of claims 1-5, characterized in that: The radar assembly (3) comprises a radar (31), a data collector (32) and a signal transceiver (33), wherein the radar (31) is installed on the mounting support (2); the data collector (32) is connected with the radar (31) and the signal transceiver (33) through data lines.

7. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to claim 6, characterized in that: The remote monitor (1) comprises a CPU processor, a signal receiver and a display, wherein the CPU processor is connected with the signal receiver and the display, and the signal receiver transmits signals to the CPU processor for processing and calculation after receiving the signals.

8. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to claim 1, characterized in that: The diversion tunnel is a gate-shaped diversion tunnel, and the corner reflectors (4) are arranged at the vault, 1 / 4 vault and arch springing of the gate-shaped diversion tunnel.

9. The millimeter wave radar-based operational period diversion tunnel surrounding rock deformation monitoring system according to claim 1, characterized in that: The diversion tunnel is a circular diversion tunnel, and the corner reflectors (4) are arranged at the top, 1 / 4 of the upper half and the position of one half of the circular diversion tunnel.

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