An automated seepage monitoring system for rockfill dams

Abstract

The present invention discloses an automatic seepage monitoring system for rockfill dams, which includes a piezometer monitoring subsystem and a monitoring background that are connected and communicate based on a wireless network; the piezometer monitoring subsystem includes a first industrial gateway connected in sequence for wireless connection with the monitoring background. A set of online monitoring system based on wireless network is established for the rockfill dam, and the data collected by the front-end equipment of the piezometer monitoring subsystem is converted into data in a compatible format through a data collector and aggregated into the first industrial gateway, and then uploaded to the monitoring background through the wireless network. In this way, the complex communication wiring work amount of the system and the construction period of the system can be reduced, and at the same time, the system has good scalability and compatibility.

Description

[0001] This application is a divisional application of the patent application with the patent number "202311058718.1", the application date of "20230822", and the title of "An Automatic Monitoring System for Rockfill Dams". Technical Field

[0002] The invention belongs to the technical field of seepage monitoring of rockfill dams, and specifically relates to an automatic seepage monitoring system for rockfill dams. Background Art

[0003] Among the reservoir dams in our country, the face rockfill dam is a relatively common dam type. However, seepage failure is the most prominent in reservoir dam failures. According to the statistical survey of the Ministry of Water Resources, about 25% of reservoir dam failures are caused by seepage problems. Therefore, it is necessary to strengthen the monitoring and analysis of dam seepage to prevent seepage failure of the dam. The data acquisition equipment for the safety monitoring of rockfill dams has mainly experienced the development process from single instrument telemetry to data acquisition systems, and the monitoring technical methods have gone through the following three stages:

[0004] (1) The prototype observation stage mainly using manual physical observation, mainly observing the deformation, temperature, and stress of the dam, with the focus on verifying the design and promoting the progress of dam engineering theory.

[0005] (2) The safety monitoring stage, in which the safe operation of the dam has gradually become the main purpose of dam observation.

[0006] (3) The full monitoring stage with the rapid development of safety monitoring technology, in which various detection instruments and data acquisition systems are continuously improved, and the automatic dam safety monitoring system develops and gradually connects to the international advanced level.

[0007] However, up to now, with the development of the automation technology of the existing rockfill dam safety monitoring system, there are still deficiencies in the existing monitoring technology, and there is still room for improvement in accurate data acquisition. For example, seepage monitoring is one of the important items for dam body safety monitoring. Due to factors such as the environment, equipment, and construction methods, how to obtain reliable and accurate seepage monitoring data for a long time is the premise for the safety assessment and analysis of the dam. Summary of the Invention

[0008] The purpose of the invention is to solve the above technical problems and provide an automatic seepage monitoring system for rockfill dams.

[0009] To solve the above problems, the invention is implemented according to the following technical solutions:

[0010] In a first aspect, the invention provides an automatic seepage monitoring system for rockfill dams, characterized in that it includes a piezometer monitoring subsystem and a monitoring background connected by wireless network communication;

[0011] The osmotic pressure gauge monitoring subsystem includes a first industrial gateway, a data collector, and multiple borehole osmotic pressure gauge devices connected in sequence; the first industrial gateway is wirelessly connected to the monitoring background, and the borehole osmotic pressure gauge device includes:

[0012] A piezometer tube, which is adaptively inserted into the measuring point borehole, and the piezometer tube is coated with non-woven geotextile; a boride cladding layer, a hot-sprayed aluminum layer, and a sealing paint layer are sequentially arranged on the outer surface of the piezometer tube;

[0013] A filling part, which is filled in the piezometer tube;

[0014] A first osmotic pressure gauge, which is buried in the filling part, and the cable of the first osmotic pressure gauge extends out from the upper part of the piezometer tube and is connected to the data collector.

[0015] Combined with the first aspect, the present invention also provides the first preferred embodiment of the first aspect. Specifically, the filling part includes a medium-coarse sand filter layer, a fine sand layer, a gravel filter layer, a bentonite layer, and a sealing layer arranged in sequence from bottom to top; the sealing layer is a cement slurry non-pressure backfill grouting sealing;

[0016] The first osmotic pressure gauge is installed in a fine sand bag filled with fine sand with a particle size not greater than 2 mm, and the fine sand bag is completely wrapped by the fine sand layer.

[0017] Combined with the first aspect, the present invention also provides the second preferred embodiment of the first aspect. Specifically, a concrete cover is arranged at the top of the piezometer tube, and a cable protection tube is arranged on the concrete cover, and the cable of the first osmotic pressure gauge passes through the cable protection tube;

[0018] The cable uses a hydraulic communication cable provided with a nylon outer sheath, and the cable is wrapped and protected by non-woven geotextile at the outlet section of the piezometer tube.

[0019] Combined with the first aspect, the present invention also provides the third preferred embodiment of the first aspect. Specifically, the boride cladding layer is a ternary boride cermet cladding layer prepared on the surface of the piezometer tube by using plasma cladding technology.

[0020] Combined with the first aspect, the present invention also provides the fourth preferred embodiment of the first aspect. Specifically, the osmotic pressure gauge monitoring subsystem further includes multiple pit-embedded osmotic pressure gauge devices connected to the data collector, and the pit-embedded osmotic pressure gauge device includes:

[0021] Fine sand filling material, which is filled in the measuring point burial pit;

[0022] A second osmotic pressure gauge, which is installed in a fine sand bag filled with fine sand with a particle size not greater than 2 mm, and the fine sand bag is completely wrapped by the fine sand filling material;

[0023] The protector is a hollow tubular structure with two ends connected, and the protector is horizontally buried in the fine sand filling material;

[0024] The fine sand bag wrapping the second piezometer is located in the tubular cavity of the protector, and the space between the fine sand bag and the inner wall of the protector is filled with fine sand.

[0025] In combination with the first aspect, the present invention further provides a fifth preferred implementation of the first aspect, specifically, the protector comprises an inner steel pipe, a steel mesh cage and an outer steel pipe which are sequentially sleeved from the inside to the outside;

[0026] The steel mesh cage is welded and fixed to the inner steel pipe and the outer steel pipe respectively. The steel mesh cage is a tubular hollow structure with two ends penetrated. The gaps between the steel mesh cage and the inner steel pipe and the outer steel pipe are filled with fine sand.

[0027] In combination with the first aspect, the present invention further provides a sixth preferred implementation of the first aspect, specifically, the inner and outer surfaces of the inner steel pipe and the outer steel pipe are sequentially provided with a boride cladding layer, a thermally sprayed aluminum layer and a sealing paint layer;

[0028] The outer surface of the steel mesh cage is provided with a thermal sprayed aluminum layer and a sealing paint layer.

[0029] In combination with the first aspect, the present invention further provides a seventh preferred implementation of the first aspect, specifically, the buried piezometer device further comprises an outer protective tube provided with a protector, the outer diameter of the outer protective tube being much larger than the protector; the inner and outer surfaces of the outer protective tube are sequentially provided with a thermal sprayed aluminum layer and a sealing paint layer;

[0030] The inner wall of the outer protective tube and the outer wall of the protector do not contact each other, and the gap between the protector and the outer protective tube is filled with fine sand.

[0031] In combination with the first aspect, the present invention further provides an eighth preferred implementation of the first aspect. Specifically, the automatic seepage monitoring system for rockfill dams further includes a water measuring weir monitoring subsystem, and the water measuring weir monitoring subsystem includes:

[0032] A water measuring weir is arranged in a straight section of the drainage ditch of the rockfill dam; a concave vertical groove is provided on the side wall of the weir groove of the water measuring weir;

[0033] a water measuring weir meter, which is arranged in the inner concave vertical groove;

[0034] A second industrial gateway is connected to the water measuring weir meter, and the second industrial gateway is wirelessly connected to the monitoring background;

[0035] A water retaining cover is arranged above the water measuring weir meter and the second industrial gateway to block rainwater.

[0036] In combination with the first aspect, the present invention also provides the 9th preferred implementation manner of the first aspect. Specifically, the rockfill dam automatic seepage monitoring system further includes a fiber Bragg grating monitoring subsystem, which includes a plurality of fiber Bragg grating temperature sensors, an optical cable heating device, a signal processor, and a third industrial gateway. The third industrial gateway is wirelessly connected to the monitoring background;

[0037] A plurality of the fiber Bragg grating temperature sensors are arranged along the peripheral joint of the rockfill dam at a spacing of 100 m per one;

[0038] A plurality of the fiber Bragg grating temperature sensors are connected to the signal processor. The third industrial gateway is provided with a data processing module based on edge computing. The data processing module processes the sampled data, makes a warning identification determination according to the warning rule parameters, and performs information synthesis and superposition processing on the fiber information data, warning information data, and target location information, and sends them to the third industrial gateway.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. The present invention provides a rockfill dam automatic seepage monitoring system, which includes a piezometer monitoring subsystem and a monitoring background based on wireless network connection communication; the piezometer monitoring subsystem includes a first industrial gateway connected in sequence for wireless connection with the monitoring background. For the rockfill dam, an online monitoring system based on the wireless network is established. The data collected by the front-end equipment of the piezometer monitoring subsystem is converted into data in a compatible format by a data collector and aggregated into the first industrial gateway, and then uploaded to the monitoring background through the wireless network, thereby reducing the complex communication wiring workload and the construction period of the system. At the same time, the system has good scalability and compatibility.

[0041] 2. In the present invention, the outer covering of the piezometer tube is provided with non-woven geotextile to prevent soil particles from entering the piezometer tube and avoid affecting the accuracy and stability of the measured value.

[0042] 3. The soil environment, seepage fluid, etc. of the rockfill dam have a certain corrosiveness to rigid materials, resulting in the piezometer tube being easily corroded and it is difficult to reach the predetermined safe service life, seriously affecting the service life and the accuracy and stability of the automatic measured value. Therefore, in the present invention, a boronized coating layer, a hot-sprayed aluminum layer, and a sealing paint layer are sequentially arranged on the outer surface of the piezometer tube to form an anti-corrosion system for improving the service life of the piezometer tube, thereby ensuring the long-term normal operation of the piezometer tube, extending its service life, and ensuring the accuracy and stability of the automatic measured value. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The following further details the specific implementation manners of the present invention with reference to the drawings, where:

[0044] Figure 1It is the system composition diagram of an automatic seepage monitoring system for a rockfill dam of the present invention;

[0045] Figure 2 It is the structural schematic diagram of the borehole type piezometer device of the present invention;

[0046] Figure 3 It is the structural schematic diagram of the pit-embedded piezometer device of the present invention;

[0047] Figure 4 It is the schematic diagram of the composition of the piezometer of the present invention;

[0048] Figure 5 It is the structural schematic diagram of the protector of the present invention;

[0049] Figure 6 It is the measuring point layout diagram of the longitudinal and transverse sections of the dam body in the project example of the present invention.

[0050] In the figure:

[0051] 10 - piezometer tube, 11 - concrete cover, 12 - cable protection tube;

[0052] 20 - filling part;

[0053] 30 - first piezometer;

[0054] 40 - outer protection tube;

[0055] 50 - protector, 51 - inner steel pipe, 52 - steel bar cage, 53 - outer steel pipe;

[0056] 60 - second piezometer;

[0057] 70 - fine sand filler. Specific embodiments

[0058] The following is a description of the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0059] The monitoring technology of rockfill dams includes technical diagnosis and safety assessment analysis. Technical diagnosis mainly obtains information on possible problems and damages of rockfill dams through daily inspection tours and inspections with safety monitoring instruments. Then, according to the characteristics of the rockfill dam itself, a diagnostic project system for the rockfill dam is constructed, and a comparative analysis method of simulation calculation and monitoring data is adopted to finally conduct special and comprehensive diagnoses on the health status of the rockfill dam, thereby providing a scientific basis for the safety assessment of the rockfill dam. The safety monitoring of rockfill dams is an important means to ensure the safe operation of dams. Dam safety monitoring includes instrument monitoring and inspection tours, and the two form an organic whole and complement each other. Instrument monitoring is to collect corresponding monitoring data by installing corresponding monitoring instruments, and with the development of computers, automated collection has been gradually realized.

[0060] Seepage monitoring refers to the monitoring of the seepage flow rate, seepage pressure, and the water level line in the dam body generated by the action of the water level difference between the upstream and downstream of the dam. Seepage monitoring mainly includes seepage in the dam body and foundation, seepage around the dam, and seepage flow rate of the dam, etc. Seepage monitoring is one of the important items of dam body safety monitoring. Under factors such as the environment, equipment, and construction methods, how to obtain accurate, reliable, and precise seepage monitoring data in the long term is a prerequisite for the safety assessment and analysis of the dam. For this reason, the present invention provides an automated seepage monitoring system for rockfill dams.

[0061] Embodiment 1

[0062] As Figure 1 shown, Embodiment 1 of the present invention provides an automated seepage monitoring system for rockfill dams. The automated monitoring system includes a monitoring background, a piezometer monitoring subsystem, a weir monitoring subsystem, and a fiber Bragg grating monitoring subsystem. Among them, the monitoring background communicates and interacts with the piezometer monitoring subsystem, the weir monitoring subsystem, and the fiber Bragg grating monitoring subsystem through a wireless network to achieve performance such as automated collection, analysis, and early warning and alarm of monitoring data.

[0063] The construction workload of the traditional automated monitoring system for rockfill dams mainly focuses on the laying of various communication lines. Especially for the weir and measuring points around the dam that are far from the monitoring station house, it is usually necessary to lay lines to connect remote acquisition devices. This method increases the construction cost and prolongs the project cycle. At the same time, the laid lines are easily damaged, etc., which easily causes problems such as lack of stability and reliability in data transmission.

[0064] To this end, according to relevant specification requirements, the present invention has set up subsystems such as seepage line monitoring and seepage flow monitoring for the rockfill dam. The piezometer monitoring subsystem includes a first industrial gateway, a data collector, a plurality of borehole piezometer devices and a plurality of pit-embedded piezometer devices connected in sequence. The weir monitoring subsystem includes a weir, a weir gauge, a second industrial gateway and a water retaining cover. The fiber Bragg grating monitoring subsystem includes a plurality of fiber Bragg grating temperature sensors, an optical cable heating device, a signal processor and a third industrial gateway. Among them, the first industrial gateway, the second industrial gateway and the third industrial gateway are wirelessly connected to the monitoring background respectively. The specific equipment names are shown in Table 1.

[0065] Table 1 Composition of Equipment for Each Subsystem

[0066]

[0067]

[0068] To implement the wireless network transmission framework, the data of each subsystem of the automatic seepage monitoring system for the rockfill dam needs to be converted into the Ethernet mode for transmission. The construction of each subsystem is described separately as follows:

[0069] (1) Both the borehole piezometer device and the pit-embedded piezometer device of the piezometer monitoring subsystem adopt vibrating wire piezometers as the front-end acquisition devices, and the output signal is 4 - 20 mA. They are connected to their respective data collectors through hydraulic communication cables, and the data collectors convert them into RS-485 signals. The first industrial gateway is equipped with a serial server to convert RS-485 into RJ45. Then the first industrial gateway converts the data into the communication protocol required by the monitoring background, such as the TCP / IP format, and then transmits the data to the monitoring background through the wireless network.

[0070] (2) The weir monitoring subsystem adopts a weir gauge as the front-end acquisition device, and its output signal is in the RS-485 format. The second industrial gateway's serial server converts RS-485 into RJ45. Then the second industrial gateway converts the data into the communication protocol required by the monitoring background, such as the TCP / IP format, and then transmits the data to the monitoring background through the wireless network.

[0071] (3) The fiber Bragg grating monitoring subsystem adopts fiber Bragg grating temperature sensors as the front-end acquisition devices. The signal processor receives the optical signals of the fiber Bragg grating temperature sensors. The signal processor is the core component of the system, mainly modulating and demodulating the optical signals returned by the sensors, converting and calculating physical quantity data, and then transmitting the monitoring data to the third industrial gateway. The third industrial gateway converts the monitoring data into the communication protocol required by the monitoring background, such as the TCP / IP format, and then transmits the data to the monitoring background through the wireless network.

[0072] The present invention establishes an online monitoring system based on wireless network for rockfill dams. The data collected by the front-end devices of each subsystem is subjected to protocol conversion through an industrial gateway, and then uploaded to the monitoring background through the wireless network, thereby reducing the complex communication wiring workload and the construction period of the system. At the same time, the system has good scalability and compatibility. On the other hand, due to the elimination of physical line laying, it can better reduce the problem of data transmission failure caused by line damage, and improve the reliability and stability of the automatic seepage monitoring of rockfill dams. The automatic monitoring system for rockfill dams has flexible networking and good scalability, and can quickly add new front-end devices to the existing network without laying a new transmission network or adding equipment, making it easier to achieve remote wireless monitoring.

[0073] In a specific implementation, the monitoring background is mainly provided with a server, a terminal deployed with online monitoring management related program software, an online UPS, etc.

[0074] Embodiment 2

[0075] The structure and working principle of the automatic seepage monitoring system for rockfill dams described in this Embodiment 2 are exactly the same as those described in Embodiment 1. The purpose of this Embodiment 2 is to provide a borehole piezometer device that can reliably and accurately obtain seepage monitoring data for a long time.

[0076] Seepage failure problems usually occur in relatively hidden parts of the dam body and dam foundation, and it is difficult to accurately judge them through manual inspections. Therefore, it is necessary to install and bury automatic front-end devices composed of piezometers and water level gauges, and other monitoring facilities to comprehensively and accurately diagnose the seepage situation of the dam, and prevent seepage failure of the dam. For this reason, the long-term, reliable and accurate sampling data of the monitoring equipment is very important for diagnosis.

[0077] As Figure 2 shown, the borehole piezometer device includes a piezometer tube 10, a filling part 20, and a first piezometer 30. Among them, the piezometer tube is adaptively inserted into the measuring point borehole of the rockfill dam, a filling part is arranged inside the piezometer tube, the first piezometer is buried in the filling part, and the cable of the first piezometer extends out from the upper part of the piezometer tube and is connected to the data collector.

[0078] In a specific implementation, the measuring points are arranged according to the scale and grade of the dam project, the characteristics of the rockfill dam, and combined with the actual project and the upstream and downstream impacts to comprehensively reflect the working state of the dam. Determine the borehole depth according to the design requirements and drill the measuring points; install the piezometer tube after drilling, and fill the filling part and the first piezometer into the piezometer tube.

[0079] In the preferred implementation, the air in the inner cavity of the permeable stone must be exhausted before the piezometer is installed, otherwise serious hysteresis or measurement errors will occur after installation, and even unstable readings will be caused; before the piezometer is installed, the instrument must be immersed in water for more than 4 hours to reach a saturated state to ensure the accuracy of the readings.

[0080] In a specific implementation, the packing part includes a medium-coarse sand filter material layer, a fine sand layer, a gravel filter material layer, a bentonite layer and a sealing layer arranged in sequence from bottom to top; the sealing layer is a cement slurry pressureless backfill grouting sealing hole; the first piezometer is filled with a fine sand bag filled with fine sand with a particle size not greater than 2 mm, and the fine sand bag is completely wrapped by the fine sand layer. Through this design, the structure of the packing part ensures that the installation method of the piezometer is correct and effective.

[0081] Specifically, in order to realize the long-term reliable and accurate sampling of the borehole piezometer device, the present invention provides the following three improvements:

[0082] (1) The end of the first piezometer permeable stone is wrapped with a permeable membrane material, such as a non-woven geotextile, to prevent the permeable stone from being blocked by solid particles adsorbed on it and affecting the flow of water, resulting in a low piezometer reading.

[0083] (2) A concrete cover 11 is provided on the top of the pressure measuring tube 10, and the concrete cover 11 is provided with a cable protection tube 12, and the cable of the first piezometer is passed through the cable protection tube; the cable adopts a hydraulic communication cable provided with a nylon outer sheath, and the cable is wrapped and protected with a non-woven geotextile at the outlet section of the pressure measuring tube to avoid damage to the piezometer cable.

[0084] Through this design, the concrete cover is used to seal the top of the piezometer to prevent rainwater from entering the piezometer and affecting the sampling data of the piezometer. On the other hand, the cable protection tube, the nylon outer sheath of the cable and the non-woven geotextile are all used to protect the communication cable of the piezometer to reduce the failure of the piezometer due to cable damage, sampling failure and other problems, and work together to improve the protection of the piezometer so that the piezometer can work reliably and accurately for a long time.

[0085] In a preferred implementation, the nylon outer sheath can be formed by extrusion of UV-crosslinked nylon material. UV-crosslinked nylon has high thermal stability, creep resistance, stress cracking resistance, mechanical strength and other properties, and has excellent corrosion resistance and wear resistance, which greatly improves the toughness and wear resistance of hydraulic communication cables and better protects hydraulic communication cables. The cable protection tube adopts an L-shaped stainless steel tube, and the cable protection tube is pre-buried in the concrete cover.

[0086] (3) The piezometer tube is coated with non-woven geotextile; the outer surface of the piezometer tube is sequentially provided with a boride cladding layer, a hot-sprayed aluminum layer, and a sealing paint layer. In the present invention, the piezometer tube is coated with non-woven geotextile to prevent soil particles of the rockfill dam from entering the piezometer tube and avoid affecting the accuracy and stability of the measured values.

[0087] On the other hand, the soil environment, seepage fluid, etc. of the rockfill dam have certain corrosivity to rigid materials, resulting in the piezometer tube being easily corroded and it is difficult to reach the predetermined safe service life, seriously affecting the service life and the accuracy and stability of the automated measured values. For this reason, in the present invention, a corrosion prevention system for improving the service life of the piezometer tube is formed by sequentially arranging a boride cladding layer, a hot-sprayed aluminum layer, and a sealing paint layer on the outer surface of the piezometer tube, so as to ensure the long-term normal operation of the piezometer tube, extend its service life, and ensure the accuracy and stability of the automated measured values of the borehole osmometer device.

[0088] To sum up, through the three technical improvements of the present invention, they are mutually synergistic, so that each borehole osmometer device can operate normally for a long time, and synergistically improve the accuracy and stability of the automated measured values of the borehole osmometer device.

[0089] In a specific implementation, the piezometer tube is composed of two parts: a water-permeable pipe section and a water-conducting pipe section. The water-permeable pipe section can be processed and manufactured with the pipe material of the water-conducting pipe. The pipe body of the water-permeable pipe is drilled in a plum blossom shape, and the area opening ratio is 10% - 20%. The piezometer tube is an existing technology in this field and will not be described in detail here.

[0090] Embodiment Three

[0091] The structure and working principle of the rockfill dam automated seepage monitoring system described in this Embodiment Three are exactly the same as those described in Embodiment Two. The purpose of this Embodiment Three is to provide a preferred structure of the piezometer tube.

[0092] After research by the applicant, it is found that according to the on-site investigation of the renovation construction, the effective measurement range of the in-service piezometer tube shortens after a period of time, and even loses the monitoring function. There are two reasons for this situation. One is the piezometer tube itself, and the other is the environment. For the reasons of the piezometer tube:

[0093] ① Natural oxidation and rust: The piezometer tubes in this field are generally made of galvanized pipes, usually manifested as the disappearance of the galvanized layer, the overall oxidation and rust of the piezometer tube, and the rust degree is relatively uniform.

[0094] ② Electrochemical corrosion: Usually appears in the water surface boundary change area inside the tube, in areas with relatively serious dam seepage or areas with relatively low terrain downstream of the dam.

[0095] ③ Pipe body perforation: Due to the complex geological conditions, in the stratum boundary change zone, some infiltration zones are formed outside the pipe after a long time, which causes local corrosion to the outside of the pipe body and forms corrosion perforation over time.

[0096] Hot-dip galvanized pipes are made by reacting molten metal with an iron matrix to produce an alloy layer, thereby combining the matrix and the coating. In the traditional technology in this field, the pressure measuring tube must use hot-dip galvanized pipes, otherwise it is difficult to meet the anti-corrosion requirements, which seriously affects the appearance quality and service life. However, due to the soil environment of the rockfill dam, some rigid materials are highly corrosive; the pressure measuring tubes constructed on site are galvanized steel pipes for corrosion protection. After a period of time, the galvanized steel pipes have been severely corroded, making it difficult to reach the predetermined safe service life, and seriously affecting the reliability and accuracy of the piezometer measurement value.

[0097] To this end, the present invention provides a new type of pressure measuring tube, by setting a boride cladding layer, a hot-sprayed aluminum layer and a sealing paint layer on the pressure measuring tube. Specifically, the boride cladding layer is a ternary boride metal ceramic coating prepared on the surface of the pressure measuring tube by plasma cladding technology.

[0098] In a preferred implementation, the cladding powder for preparing the boride cladding layer includes the following raw materials in percentage by mass: Mo 35.0%, B 8.0%, Si 1.0%, Cr 10.0%, C 0.5%, Ni 2.0%, and the balance is Fe.

[0099] Through this design, the boride cladding layer is equivalent to 304 stainless steel under neutral conditions, and the corrosion resistance of the boride cladding layer is better than 304 stainless steel under acidic conditions; through a large number of mesh borides, high concentrations of Mo and Cr form a dense oxide film in an acidic solution, which is beneficial to improving the corrosion resistance of the boride cladding layer. In order to form an anti-corrosion system on the outer surface of the pressure measuring tube with better anti-corrosion performance than 304 stainless steel pipe and improve the service life of the pressure measuring tube, the long-term normal operation of the pressure measuring tube is guaranteed, its service life is extended, and the accuracy and stability of the automatic measurement are guaranteed.

[0100] On the other hand, the boride cladding layer also has a relatively high hardness, which can effectively increase the surface hardness of the pressure measuring tube and reduce the damage to the pressure measuring tube during the installation process or the environment.

[0101] In a preferred implementation, the pressure measuring tube is made of 1Cr15Ni4Mo3N steel, which has high strength and corrosion resistance. Through the combination of 1Cr15Ni4Mo3N steel, boride cladding layer, thermal aluminum spraying and sealing paint, under this specific technical means, the corrosion resistance of the pressure measuring tube is greatly optimized, and it can cope with the installation environment and soil environment of most rockfill dams. The service life is far superior to that of traditional galvanized steel pipes, and the anti-corrosion effect is better than that of 316 stainless steel pipes, which effectively extends the service life of the pressure measuring tube and has a long service life.

[0102] In a preferred embodiment, a steel bar layer is provided between the outer wall of the piezometer tube and the non-woven geotextile. Multiple annularly distributed steel bars are welded to the outer wall of the piezometer tube and then wrapped with non-woven geotextile. Specifically, the steel bars are made of 1Cr15Ni4Mo3N steel, and the length is adapted to the length of the water permeable pipe section. After welding, a boride cladding layer, hot sprayed aluminum and sealing paint are provided. On the one hand, the steel bars enhance the structural strength of the piezometer tube and reduce the bending of the tube body or tube section caused by the environment.

[0103] Example 4

[0104] A rockfill dam automatic seepage monitoring system described in this Example 4 has exactly the same structure and working principle as that described in Example 1. The piezometric pressure gauge monitoring subsystem described in this Example 4 further includes a plurality of buried piezometric pressure gauge devices connected to the data acquisition instrument.

[0105] There are two commonly used embedding methods for vibrating wire piezometers in the construction of seepage monitoring systems. One is to install them in a drill hole, and this method is more commonly used in existing buildings such as reservoir dams. The other is to dig a pit and embed them in the dam body and fill soil. This method is applicable to the installation of piezometers before the construction of reservoir dams during the engineering construction. Embed the piezometer during the dam filling process: measurement and setting out → pit excavation → instrument embedding → cable laying. During the cable laying process, dig a cable trench, and the cable of the piezometer should be laid in an S shape. The present invention obtains relatively comprehensive sampling data by jointly measuring values with a plurality of borehole piezometer devices and a plurality of buried piezometer devices; on the other hand, according to actual needs, the borehole piezometer device or the buried piezometer device can be selected.

[0106] As Figure 3 shown, the buried piezometer device includes fine sand filling material 70 for filling the buried pit at the measuring point, a second piezometer 60 and a protector 50. The second piezometer is installed in a fine sand bag filled with fine sand with a particle size not greater than 2 mm, and the fine sand bag is completely wrapped by the fine sand filling material; the protector is a hollow tubular structure with both ends penetrating, and the protector is horizontally buried in the fine sand filling material; wherein, the fine sand bag wrapping the second piezometer is located in the tubular cavity of the protector, and the space between the fine sand bag and the inner wall of the protector is filled with fine sand.

[0107] Through research by the applicant, it is found that there is a possibility that the second piezometer buried in the clay core wall is affected by the rolling of the core wall, resulting in strain in the piezometer structure, thereby affecting the accuracy and reliability of the piezometer measurement value; in addition, the earth-rock pressure in the upper part of the rockfill dam is relatively large, which may also affect the piezometer sensor. Therefore, in the present invention, a protector is provided for the second piezometer, and a protection structure is provided for the second piezometer without affecting the measurement work of the second piezometer, greatly reducing the influence of the core wall rolling and the earth-rock pressure of the rockfill dam on the second piezometer, thereby improving the accuracy and reliability of the piezometer measurement value.

[0108] As Figure 5 shown, the protector includes an inner steel pipe 51, a steel bar cage 52 and an outer steel pipe 53 which are sleeved and arranged in sequence from the inside to the outside; the steel bar cage is welded and fixed to the inner steel pipe and the outer steel pipe respectively, the steel bar cage is a tubular hollow structure with both ends penetrating, and fine sand is filled in the gap between the steel bar cage and the inner steel pipe and the outer steel pipe. Through this design, the protector has good structural strength and does not deform.

[0109] In a preferred embodiment, boride cladding layers, hot spray aluminum layers and sealing paint layers are sequentially arranged on the inner and outer surfaces of the inner steel pipe and the outer steel pipe; hot spray aluminum layers and sealing paint layers are arranged on the outer surface of the steel bar cage. For the specific description of the boride cladding layer, refer to the statement of Embodiment III.

[0110] Through this design, the boride cladding layer is equivalent to 304 stainless steel under neutral conditions, and the corrosion resistance of the boride cladding layer is better than that of 304 stainless steel under acidic conditions; in a large number of network borides, high-concentration Mo and Cr generate dense oxide films in acidic solutions, which is beneficial to improving the corrosion resistance of the boride cladding layer. To form an anti-corrosion system with better anti-corrosion performance than 304 stainless steel pipe on the outer surface of the piezometer tube, improve the service life of the protector, thereby providing a long-term protection effect for the protector, extending its service life and ensuring the accuracy and stability of automatic measurement.

[0111] Specifically, the pit-embedded piezometer device further includes an outer protection tube 40 sleeving the protector, and the outer diameter of the outer protection tube is much larger than that of the protector; hot spray aluminum layers and sealing paint layers are sequentially arranged on the inner and outer surfaces of the outer protection tube, the inner wall of the outer protection tube does not contact the outer wall of the protector, and the gap between the protector and the outer protection tube is filled with fine sand.

[0112] Under the action of loads such as self-weight, water pressure, and temperature, the dam will undergo corresponding deformations, including surface vertical displacement. On the other hand, due to this property of the rockfill body, a large part of the settlement deformation of the rockfill dam is completed during the construction period and the first impoundment period, and the remaining settlement is basically completed within 3 years during the operation period. By forming a gap between the outer protection pipe and the protector without contact, and filling fine sand in the gap, a buffer space is formed between the outer protection pipe and the protector, which can better protect the second piezometer, transfer the influence of core wall rolling and the earth-rock pressure of the rockfill dam to the protection structure composed of the outer protection pipe and the protector, and place the second piezometer inside the outer protection pipe and the protector, greatly reducing the influence of core wall rolling and the earth-rock pressure of the rockfill dam on the second piezometer, thereby improving the measurement accuracy and reliability of the piezometer.

[0113] Embodiment Five

[0114] A rockfill dam automatic seepage monitoring system described in this Embodiment Five has exactly the same structure and working principle as that described in Embodiment One. This Embodiment Five specifically describes the implementation of the weir monitoring subsystem and the fiber Bragg grating monitoring subsystem.

[0115] Among them, the weir monitoring subsystem includes:

[0116] A weir, which is arranged on the straight section of the drainage ditch of the rockfill dam; an inwardly concave vertical groove is opened on the side wall of the weir trough of the weir;

[0117] A weir gauge, which is arranged in the inwardly concave vertical groove;

[0118] A second industrial gateway, which is connected to the weir gauge, and the second industrial gateway is wirelessly connected to the monitoring background;

[0119] A water shield, which is arranged above the weir gauge and the second industrial gateway to block rainwater.

[0120] The seepage flow of the dam body is monitored by installing a weir at the downstream part of the rockfill dam. The type of weir is selected according to the size of the seepage flow: when the flow rate is between 1 and 70 L / s, a right-angled triangular weir is selected; when the seepage flow is between 10 and 300 L / s, a trapezoidal weir is used; when the seepage flow is greater than 50 L / s, a rectangular weir is used. The weir can quantitatively measure the total seepage flow of the earth-rock dam (including the dam foundation and seepage around the dam), and combined with the seepage monitoring instruments inside the dam, the seepage situation of the earth-rock dam body can be judged as a whole, and then the operation situation of the dam body can be judged.

[0121] The main improvement of the present invention lies in that a water baffle is arranged above the water measuring weir gauge and the second industrial gateway to block rainwater. The water baffle is in a "person" shape structure and is formed by integral injection molding of epoxy resin, or can also be formed by bending a stainless steel plate. The water baffle is fixed on the upper surface of the water measuring weir through a frame, and the frame is a hollow cube frame welded by several stainless steel square tubes. The water baffle is fixed on the top of the frame, and a water baffle can be arranged on the side wall of the frame. Through this design, it is ensured that the water measuring weir gauge does not directly contact rainwater, thereby ensuring the accuracy and reliability of instrument measurement.

[0122] Among them, the fiber Bragg grating monitoring subsystem includes a plurality of fiber Bragg grating temperature sensors, an optical cable heating device, a signal processor, and a third industrial gateway, and the third industrial gateway is wirelessly connected to the monitoring background;

[0123] A plurality of the fiber Bragg grating temperature sensors are arranged at intervals of 100 m along the peripheral joint of the rockfill dam;

[0124] A plurality of the fiber Bragg grating temperature sensors are connected to the signal processor. The third industrial gateway is provided with a data processing module based on edge computing. The data processing module processes the sampled data and makes a warning identification determination according to the warning rule parameters, and performs information synthesis and superposition processing on the fiber information data, warning information data, and target position information, and sends them to the third industrial gateway.

[0125] This patent adopts the thermal pulse method, which is a monitoring method that determines the leakage phenomenon by heating the optical fiber and then analyzing the temperature difference in the monitoring area. The key technology is to study the corresponding relationship between the seepage field and the temperature field in the dam body. Specifically, the fiber Bragg grating monitoring subsystem is an existing technology in the field, and will not be elaborated here.

[0126] Specifically, when the fiber Bragg grating temperature sensor senses a change in the remotely measured quantity, it will cause a change in wavelength, and the wavelength change is transmitted to the signal processor; the signal processor is the core component of the system, mainly modulating and demodulating the optical signal returned by the sensor, converting and calculating physical quantity data; the third industrial gateway is equipped with an edge computing module for intelligent detection and identification to obtain identification data. The third industrial gateway mainly completes the information superposition and processing of the intelligent analysis results, makes a warning identification determination on the identification data according to the warning rule parameters, and performs information synthesis and superposition processing on the identification data, fiber information data, warning information data, target position information, etc., and performs communication protocol conversion and wireless transmission.

[0127] Project Example

[0128] Taking the upgrade and transformation of the automatic monitoring system of a certain reservoir dam in Guangzhou City as an example, this project example provides an example of the layout of the piezometer monitoring subsystem of a rockfill dam automatic seepage monitoring system.

[0129] The dam site of a certain reservoir dam is located in the lower reaches of Fentian Water, a tributary of the Liuxi River. It is a medium-sized reservoir mainly for irrigation, combined with flood control, power generation and other comprehensive utilization. The reservoir dam is designed according to the flood of once in 100 years and checked according to the flood of once in 1000 years. The catchment area is 92.3 KM 2 , with an average annual rainfall of 1995 mm, a total reservoir capacity of 90.97 million ㎡, and an average annual inflow of 1.0204 billion m 3 , with an average annual outflow of 966.3 million m 3 . The dead water level of the reservoir is 139.91 m, with a corresponding reservoir capacity of 24 million m 3 ; the normal water level (flood limit water level) is 175.01 m (Zhuji, the same below), with a corresponding reservoir capacity of 828.9 million m 3 ; the design flood level is 175.85 m, with a corresponding reservoir capacity of 869.8 million m 3 ; the checked flood level: 176.44 m, with a corresponding reservoir capacity of 90.97 million m 3 .

[0130] The main buildings include the main dam, spillway, power station and water conveyance tunnel. The main dam is a masonry gravity dam, with a dam length of 181.9 m, a maximum dam height of 61.3 m and a dam top width of 5 m. There are two flood discharge sluices arranged on the overflow dam, and two 8 m×7 m steel arc gates are arranged, and two 25 t single-drum double-hook hoisting machines are used for opening and closing, with a designed discharge of 765 m 3 / s. Since the project was completed, it has been operating normally and has fully exerted the social, economic and ecological benefits of irrigation, flood control, power generation, etc.

[0131] (1) System composition:

[0132] The system consists of three-level networks of measurement and control network, local area network and remote Internet, connecting the on-site measurement and control layer, project management layer and superior management layer to form a monitoring, management and multi-level decision support system. Specifically, the piezometer monitoring subsystem refers to the architecture of Embodiment 1 and Figure 1 is set up.

[0133] (2) Arrangement of the piezometer monitoring subsystem:

[0134] A total of 4 sets of telemetry leakage meters are arranged on the dam to measure the leakage of the dam body or the dam foundation respectively. The leakage of the left bank dam foundation is measured by the telemetry leakage meter arranged at the elevation of ▽130 m in the left bank foundation gallery; the leakage of the right bank dam foundation is measured by the telemetry leakage meter arranged at the elevation of ▽140 m in the right bank foundation gallery; the leakage of the left bank dam foundation below the elevation of ▽130 m and the leakage of the right bank dam foundation below the elevation of ▽140 m are measured by the telemetry leakage meter arranged at the entrance of the gallery at the elevation of ▽121 m; the leakage of the dam body is measured by the telemetry leakage meter arranged in the gallery at the elevation of ▽127.

[0135] (3) Replacement of piezometers for monitoring uplift pressure of dam foundation:

[0136] A total of 11 piezometers were installed along the entire longitudinal gallery of a reservoir dam from the elevation of 152m on the left bank to the horizontal section at the elevation of 127m, and then to the elevation of 147m on the right bank. Another 4 piezometers were installed along the foundation gallery at the elevation of 121m to detect the uplift pressure of the dam foundation. The original piezometers were aging and unstable, so all 15 piezometers are planned to be replaced in this project.

[0137] Imported GK-4500S standard piezometers are used to measure fluid pressure. For example, when buried in the dam body or fill, they can monitor the groundwater level and pore water pressure, etc. They can also be installed in boreholes, observation wells or piezometric tubes.

[0138] 3.1 The technical indicators of the piezometer are as follows:

[0139] Sensor type: vibrating wire type;

[0140] Model: GK-4500S;

[0141] Range: 0.35MPa (behind the impervious body, foundation and dam body, in piezometric tubes), 1.0MPa (in front of the impervious body);

[0142] Sensitivity: 0.025%F.S;

[0143] Nonlinearity: ≤0.1%F.S;

[0144] Temperature range: -20℃~80℃.

[0145] Calibration time: 10 years.

[0146] 3.2 The technical indicators of the piezometric tube are as follows:

[0147] Selection of piezometric tube material: The piezometric tube of Embodiment 3 of the present invention is adopted. The piezometric tube is made of 1Cr15Ni4Mo3N steel, and a boride cladding layer, hot-sprayed aluminum and sealing paint are provided on the outer surface of the piezometric tube.

[0148] (4) Seepage around the dam:

[0149] At present, only the project of monitoring the uplift pressure of the dam foundation is set for this reservoir, while the seepage around the dam monitoring project is not set at the two abutments of the dam. Generally, the joint part of the two abutments of the reservoir is the weak link of the dam and is prone to danger. Therefore, it is necessary to supplement the seepage around the dam monitoring project to comprehensively and completely monitor the seepage condition of the dam.

[0150] The magnitude and distribution of the seepage around the dam are mainly related to factors such as the geological characteristics of the two abutments, the degree of fissures, the quality of curtain grouting, and the effectiveness of the drainage system. According to the specific situation of this dam, along the joint of the two abutments, from the dam crest to the downstream side of the foundation grouting gallery, 5 piezometers for seepage around the dam (1 section) are respectively arranged, with a total of 10 measuring points. The piezometers adopt the piezometers of Embodiment 3 of the present invention.

[0151] The imported GK-4500S type standard osmometer is used to measure the fluid pressure. For example, when buried in the dam body and fill, it can monitor the groundwater level and pore water pressure, etc., and can also be installed in boreholes, observation wells or piezometers.

[0152] 4.1 The technical indicators of the osmometer are as follows:

[0153] Sensor type: vibrating wire type;

[0154] Model: GK-4500S;

[0155] Range: 0.35 MPa (behind the impervious body, in the foundation and dam body, inside the piezometer), 1.0 MPa (in front of the impervious body);

[0156] Sensitivity: 0.025% F.S;

[0157] Nonlinearity: ≤0.1% F.S;

[0158] Temperature range: -20°C to 80°C.

[0159] Calibration time: 10 years.

[0160] 4.2 The technical indicators of the piezometer are as follows:

[0161] Selection of piezometer material: The piezometer of Embodiment 3 of the present invention is adopted. The piezometer is made of 1Cr15Ni4Mo3N steel, and a boride cladding layer, hot spray aluminum and sealing paint are provided on the outer surface of the piezometer. For other structures of the rockfill dam automatic seepage monitoring system described in this embodiment, refer to the prior art.

[0162] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An automatic seepage monitoring system for a rockfill dam, characterized in that, it includes a piezometer monitoring subsystem and a monitoring background that communicate based on a wireless network connection; The piezometer monitoring subsystem includes a first industrial gateway, a data collector, and multiple borehole piezometer devices connected in sequence; the first industrial gateway is wirelessly connected to the monitoring background, and the borehole piezometer device includes: A piezometer tube, which is adaptively inserted into the measuring point borehole. The piezometer tube is made of 1Cr15Ni4Mo3N steel. Multiple annularly distributed steel bars are welded on the outer wall of the piezometer tube. The steel bars are made of 1Cr15Ni4Mo3N steel. The piezometer tube is coated with non-woven geotextile; A boride cladding layer, a thermal sprayed aluminum layer, and a sealing paint layer are sequentially arranged on the outer surface of the piezometer tube; A filler part, which is filled in the piezometer tube; A first piezometer, which is buried in the filler part. The cable of the first piezometer extends from the upper part of the piezometer tube and is connected to the data collector; Among them, the boride cladding layer is a ternary boride cermet cladding layer prepared on the surface of the piezometer tube by plasma cladding technology; the cladding powder for preparing the boride cladding layer consists of raw materials with the following percentage mass fractions: Mo 35.0%, B 8.0%, Si 1.0%, Cr 10.0%, C 0.5%, Ni 2.0%, and the balance is Fe; The piezometer monitoring subsystem also includes multiple pit-embedded piezometer devices connected to the data collector. The pit-embedded piezometer device includes: Fine sand filler, which is filled in the measuring point burial pit; A second piezometer, which is installed in a fine sand bag filled with fine sand with a particle size not greater than 2 mm. The fine sand bag is completely wrapped by the fine sand filler; A protector, which has a hollow tubular structure with both ends penetrating. The protector is horizontally buried in the fine sand filler; Among them, the fine sand bag wrapping the second piezometer is located in the tubular cavity of the protector, and fine sand is filled between the fine sand bag and the inner wall of the protector; The protector includes an inner steel pipe, a steel wire mesh cage, and an outer steel pipe sleeved in sequence from the inside to the outside; The steel wire mesh cage is welded and fixed to the inner steel pipe and the outer steel pipe respectively. The steel wire mesh cage is a tubular hollow structure with both ends penetrating. Fine sand is filled in the gap between the steel wire mesh cage and the inner steel pipe and the outer steel pipe; The inner and outer surfaces of the inner steel pipe and the outer steel pipe are sequentially provided with a boride cladding layer, a thermal sprayed aluminum layer, and a sealing paint layer; the cladding powder of the boride cladding layer of the inner steel pipe and the outer steel pipe consists of raw materials with the following percentage mass fractions: Mo 35.0%, B 8.0%, Si 1.0%, Cr 10.0%, C 0.5%, Ni 2.0%, and the balance is Fe; The outer surface of the steel wire mesh cage is provided with a thermal sprayed aluminum layer and a sealing paint layer.

2. The automatic seepage monitoring system for a rockfill dam according to claim 1, characterized in that: The filler part includes a medium and coarse sand filter layer, a fine sand layer, a gravel filter layer, a bentonite layer, and a sealing layer arranged in sequence from bottom to top; the sealing layer is a cement slurry non-pressure backfill grouting seal; The first piezometer is installed in a fine sand bag filled with fine sand with a particle size not greater than 2 mm, and the fine sand bag is completely wrapped by the fine sand layer.

3. The automatic seepage monitoring system for rockfill dam according to claim 1, Features: A concrete cover is provided on the top of the pressure measuring tube, and the concrete cover is provided with a cable protection tube, and the cable of the first piezometer is passed through the cable protection tube; The cable is a hydraulic communication cable provided with a nylon outer sheath, and the cable is wrapped and protected with a non-woven geotextile at the outlet section of the pressure measuring tube.

4. The automatic seepage monitoring system for rockfill dam according to claim 1, Features: The buried piezometer device also includes an outer protective tube with a protector, the outer diameter of the outer protective tube is much larger than the protector; the inner and outer surfaces of the outer protective tube are sequentially provided with a thermal sprayed aluminum layer and a sealing paint layer; The inner wall of the outer protective tube and the outer wall of the protector do not contact each other, and the gap between the protector and the outer protective tube is filled with fine sand.

5. The automatic seepage monitoring system for rockfill dam according to claim 1, It is characterized in that It also includes a water measuring weir monitoring subsystem, which includes: A water measuring weir is arranged in a straight section of the drainage ditch of the rockfill dam; a concave vertical groove is provided on the side wall of the weir groove of the water measuring weir; a water measuring weir meter, which is arranged in the inner concave vertical groove; A second industrial gateway is connected to the water measuring weir meter, and the second industrial gateway is wirelessly connected to the monitoring background; A water retaining cover is arranged above the water measuring weir meter and the second industrial gateway to block rainwater.

6. The automatic seepage monitoring system for rockfill dam according to claim 1, It is characterized in that It also includes a fiber Bragg grating monitoring subsystem, which includes a plurality of fiber Bragg grating temperature sensors, an optical cable heating device, a signal processor and a third industrial gateway, and the third industrial gateway is wirelessly connected to the monitoring background; A plurality of the fiber Bragg grating temperature sensors are arranged at a rate of 100 m / piece along the seams around the rockfill dam; Multiple fiber grating temperature sensors are connected to a signal processor, and the third industrial gateway is provided with a data processing module based on edge computing. The data processing module processes the sampled data and makes warning identification judgments according to the warning rule parameters, and synthesizes and superimposes the fiber information data, warning information data and target position information, and sends them to the third industrial gateway.

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