Automatic seepage monitoring system for rock-fill dam

Abstract

The invention discloses an automatic seepage monitoring system for a rock-fill dam. The automatic seepage monitoring system comprises an osmometer monitoring subsystem and a monitoring background which are connected and communicated based on a wireless network, the osmometer monitoring subsystem comprises a first industrial gateway which is connected in sequence and is used for being wirelessly connected with the monitoring background. A set of online monitoring system based on a wireless network is established for a rock-fill dam, data acquired by front-end equipment of an osmometer monitoring subsystem is converted into data in an adaptive format through a data acquisition instrument, the data is converged into a first industrial gateway, and the data is uploaded to a monitoring background through the wireless network; therefore, the complex communication wiring work amount of the system can be reduced, the construction period of the system can be shortened, and meanwhile the system has good expansibility and compatibility.

Description

[0001] This application is a divisional application of patent number "202311058718.1", application date "20230822", and name "An automated monitoring system for rockfill dams". Technical Field

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

[0003] Among the reservoir dams in my country, the panel rockfill dam is a more common dam type. However, seepage damage is the most prominent in reservoir dam failures. According to statistics from 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 damage to the dam. The development of data acquisition equipment for rockfill dam safety monitoring has mainly experienced the development process from single instrument telemetry to data acquisition system, and the monitoring technology method has gone through the following three stages:

[0004] (1) The prototype observation phase mainly uses manual physical observation to observe the deformation, temperature, and stress of the dam, with the focus on verifying the design and promoting the advancement of dam engineering theory.

[0005] (2) During the safety monitoring phase, the safe operation of the dam gradually became the main purpose of dam observation.

[0006] (3) In the full monitoring stage of rapid development of safety monitoring technology, various detection instruments and data acquisition systems are constantly being improved, and the dam safety monitoring automation system is developing and gradually meeting the international advanced level.

[0007] However, the existing automation technology of rockfill dam safety monitoring system has been developed so far, but the existing monitoring technology is still insufficient, and there is still room for improvement in accurate data collection. For example, seepage monitoring is one of the important projects of dam safety monitoring. Due to factors such as environment, equipment, and construction methods, how to obtain reliable and accurate seepage monitoring data for a long time is the premise for dam safety assessment and analysis. Summary of the invention

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

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

[0010] In a first aspect, the present invention provides an automated seepage monitoring system for a rockfill dam, characterized in that it comprises a piezometer monitoring subsystem and a monitoring background based on wireless network connection communication;

[0011] The osmometer monitoring subsystem includes a first industrial gateway, a data acquisition instrument and a plurality of borehole osmometer devices connected in sequence; the first industrial gateway is wirelessly connected to the monitoring background, and the borehole osmometer device includes:

[0012] A pressure measuring tube adapted to be inserted into a borehole at a measuring point, wherein the pressure measuring tube is coated with a non-woven geotextile; the outer surface of the pressure measuring tube is sequentially provided with a boride cladding layer, a thermally sprayed aluminum layer and a sealing paint layer;

[0013] A filler part, which is filled in the pressure measuring tube;

[0014] The first osmometer is buried in the filler part, and the cable of the first osmometer extends from the upper part of the pressure measuring tube and is connected with the data acquisition instrument.

[0015] In combination with the first aspect, the present invention further provides a first preferred implementation of the first aspect, specifically, the filler 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;

[0016] The first piezometer is loaded into a fine sand bag filled with fine sand having a particle size not greater than 2 mm, and the fine sand bag is completely wrapped by the fine sand layer.

[0017] In combination with the first aspect, the present invention further provides a second preferred implementation manner of the first aspect, specifically, a concrete cover is provided on the top of the pressure measuring tube, the concrete cover is provided with a cable protection tube, and the cable of the first piezometer is passed through the cable protection tube;

[0018] 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.

[0019] In combination with the first aspect, the present invention further provides a third preferred implementation manner of the first aspect. Specifically, the boride cladding layer is a ternary boride metal ceramic coating prepared on the surface of the pressure measuring tube by using plasma cladding technology.

[0020] In combination with the first aspect, the present invention further provides a fourth preferred implementation of the first aspect, specifically, the osmometer monitoring subsystem further includes a plurality of pit-buried osmometer devices connected to the data acquisition instrument, and the pit-buried osmometer devices include:

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

[0022] A second osmometer is placed in a fine sand bag filled with fine sand having a particle size not greater than 2 mm, wherein the fine sand bag is completely wrapped by the fine sand filler;

[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 further provides a ninth preferred implementation of the first aspect, specifically, the automatic seepage monitoring system for rockfill dam further includes a fiber Bragg grating monitoring subsystem, 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;

[0037] 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;

[0038] 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 optical fiber information data, warning information data, and target position information, and sends them to the third industrial gateway.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention provides an automated seepage monitoring system for rockfill dams, including 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. A wireless network-based online monitoring system is established for rockfill dams, 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 acquisition instrument and aggregated into the first industrial gateway, which is then uploaded to the monitoring background through a wireless network, thereby reducing the system's complex communication wiring engineering workload and the system construction cycle, while the system has good scalability and compatibility.

[0041] 2. The present invention covers the pressure measuring tube with a non-woven geotextile to prevent soil particles from entering the pressure measuring tube and affecting the accuracy and stability of the measured value.

[0042] 3. The soil environment and seepage fluid of the rockfill dam are corrosive to rigid materials, which makes the piezometer tube easily corroded and difficult to reach the predetermined safe service life, seriously affecting the service life and the accuracy and stability of the automatic measurement. To this end, the present invention sequentially arranges a boride cladding layer, a thermal sprayed aluminum layer and a sealing paint layer on the outer surface of the piezometer tube to form an anti-corrosion system that increases 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 measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0044] Figure 1This is a system composition diagram of an automated seepage monitoring system for rockfill dams of the present invention;

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

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

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

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

[0049] Figure 6 It is a measurement point arrangement diagram of the longitudinal and cross sections of the dam body of the project example of the present invention.

[0050] In the figure:

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

[0052] 20-filling part;

[0053] 30-first osmometer;

[0054] 40-external protective tube;

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

[0056] 60 - second osmometer;

[0057] 70-Fine sand filler. DETAILED DESCRIPTION

[0058] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0059] Rockfill dam monitoring technology includes technical diagnosis and safety assessment analysis. Technical diagnosis mainly obtains information about possible problems and damage of rockfill dams through daily inspections and safety monitoring instrument detection. Then, according to the characteristics of the rockfill dam itself, a rockfill dam diagnosis project system is constructed, and simulation calculations and monitoring data comparison and analysis methods are used to finally conduct special and comprehensive diagnosis of the health status of the rockfill dam, thereby providing a scientific basis for the safety assessment of the rockfill dam. Safety monitoring of rockfill dams is an important means to ensure the safe operation of dams, and dam safety monitoring includes instrument monitoring and inspections, which form an organic whole and complement each other. Instrument monitoring is to collect corresponding monitoring data by burying and installing corresponding monitoring instruments, and with the development of computers, automated collection has gradually been realized.

[0060] Seepage monitoring refers to the monitoring of the seepage volume, seepage pressure and water level line in the dam body caused by the water level difference between upstream and downstream. Seepage monitoring mainly includes the monitoring of the dam body and dam foundation seepage, seepage around the dam and dam seepage volume. Seepage monitoring is one of the important projects of dam body safety monitoring. Under the factors of environment, equipment, construction method, etc., how to obtain accurate, reliable and accurate seepage monitoring data for a long time is the premise of dam safety assessment and analysis. To this end, the present invention provides an automated seepage monitoring system for rockfill dams.

[0061] Embodiment 1

[0062] like Figure 1 As shown, this embodiment 1 provides an automated seepage monitoring system for rockfill dams, and the automated monitoring system includes a monitoring background, a piezometer monitoring subsystem, a water-measuring weir monitoring subsystem, and a fiber Bragg grating monitoring subsystem. The monitoring background communicates and interacts with the piezometer monitoring subsystem, the water-measuring weir monitoring subsystem, and the fiber Bragg grating monitoring subsystem through a wireless network to achieve automated collection, analysis, and early warning of monitoring data.

[0063] The construction workload of the traditional rockfill dam automation monitoring system is mainly concentrated on the laying of various communication lines. In particular, for measuring weirs and measuring points around the dam, which are far away from the monitoring station, it is usually necessary to lay lines to connect remote data collection equipment. This method increases construction costs and increases the project cycle. At the same time, the laid lines are easily damaged, which can easily cause problems such as lack of stability and reliability of data transmission.

[0064] To this end, the present invention sets up subsystems such as infiltration line monitoring and seepage flow monitoring equipped with rockfill dams in accordance with relevant specifications. The piezometer monitoring subsystem includes a first industrial gateway, a data acquisition instrument, a plurality of borehole piezometer devices and a plurality of buried piezometer devices connected in sequence. The water-measuring weir monitoring subsystem includes a water-measuring weir, a water-measuring weir meter, a second industrial gateway and a water retaining cover. The fiber grating monitoring subsystem includes a plurality of fiber 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 Equipment composition of each subsystem

[0066]

[0067]

[0068] In order to realize the wireless network transmission frame, the data of each subsystem of the rockfill dam automated seepage monitoring system needs to be converted into Ethernet for transmission. The construction of each subsystem is described as follows:

[0069] (1) The borehole piezometer device and the buried piezometer device of the piezometer monitoring subsystem both use vibrating-wire piezometers as front-end acquisition devices, with an output signal of 4-20 mA, which is connected to their respective data acquisition instruments through hydraulic communication cables and converted into RS-485 signals by the data acquisition instruments. The first industrial gateway is equipped with a serial port server to convert RS-485 to RJ45. The first industrial gateway then converts the data into the communication protocol conversion required by the monitoring background, such as TCP / IP format, and then transmits the data to the monitoring background through the wireless network.

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

[0071] (3) The fiber Bragg grating monitoring subsystem uses a fiber Bragg grating temperature sensor as the front-end acquisition device, and a signal processor receives the optical signal of the fiber Bragg grating temperature sensor. The signal processor is the core component of the system, which mainly performs modulation and demodulation, physical quantity data conversion and calculation on the optical signal returned by the sensor, and then transmits the monitoring data to the third industrial gateway. The third industrial gateway converts the monitoring data into the communication protocol conversion required by the monitoring background, such as 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 a wireless network for rockfill dams, converts the data collected by the front-end devices of each subsystem into a protocol through an industrial gateway, and then uploads it to the monitoring background through a wireless network, thereby reducing the complex communication wiring engineering workload and the construction cycle of the system, and the system has good scalability and compatibility. On the other hand, since the physical line laying is eliminated, the problem of data transmission failure caused by line damage can be better reduced, and the reliability and stability of the automatic monitoring of rockfill dam seepage can be improved. The automatic monitoring system for rockfill dams has flexible networking and good scalability. New front-end devices can be quickly added to the existing network, and there is no need to lay a network or add equipment for new transmission, making it easier to achieve remote wireless monitoring.

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

[0074] Embodiment 2

[0075] The structure and working principle of the automatic seepage monitoring system for rockfill dams described in the second embodiment are exactly the same as those described in the first embodiment. The purpose of the second embodiment is to provide a borehole piezometer device for obtaining seepage monitoring data reliably and accurately over a long period of time.

[0076] Seepage damage problems usually occur in more concealed areas of the dam body and foundation, and are difficult to accurately determine through manual inspections. Therefore, it is necessary to install automated front-end equipment consisting of buried pressure measuring tubes and piezometers, water measuring weir meters and other monitoring facilities to conduct a comprehensive and accurate diagnosis of the seepage conditions of the dam and prevent seepage damage to the dam. For this purpose, long-term, reliable and accurate sampling data from monitoring equipment is very important for diagnosis.

[0077] like Figure 2 As shown, the borehole piezometer device includes a piezometer 10, a filler part 20 and a first piezometer 30. The piezometer is adapted to be inserted into a borehole at a measuring point of a rockfill dam, a filler part is arranged inside the piezometer, the first piezometer is buried in the filler part, and a cable of the first piezometer extends from the upper part of the piezometer to be connected to a data acquisition instrument.

[0078] In a specific implementation, the monitoring points are arranged according to the scale and grade of the dam project, the characteristics of the rockfill dam, and the actual project and the upstream and downstream impacts, so as to fully reflect the working status of the dam. The drilling depth is determined according to the design requirements, and the measuring points are drilled; after drilling, the pressure measuring tube is installed, and the filling part and the first piezometer are filled into the pressure measuring 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 is coated with a non-woven geotextile; the outer surface of the piezometer is provided with a boride cladding layer, a thermally sprayed aluminum layer and a sealing paint layer in sequence. The present invention coats the piezometer with a non-woven geotextile to prevent soil particles of the rockfill dam from entering the piezometer and affecting the accuracy and stability of the measured value.

[0087] On the other hand, the soil environment and seepage fluid of the stone dam are corrosive to rigid materials, which makes the piezometer easily corroded and difficult to reach the predetermined safe service life, seriously affecting the service life and the accuracy and stability of the automatic measurement. To this end, the present invention sequentially arranges a boride cladding layer, a thermal sprayed aluminum layer and a sealing paint layer on the outer surface of the piezometer to form an anti-corrosion system that increases the service life of the piezometer, thereby ensuring the long-term normal operation of the piezometer, extending its service life and ensuring the accuracy and stability of the automatic measurement of the borehole piezometer device.

[0088] In summary, the three technical improvements adopted in the present invention are coordinated with each other to ensure the long-term normal operation of each borehole piezometer device and to coordinately improve the accuracy and stability of the automated measurement of the borehole piezometer device.

[0089] In a specific implementation, the pressure measuring tube is composed of a water permeable pipe section and a water conducting pipe section. The water permeable pipe section can be processed and manufactured with water conducting pipe materials, and the holes of the water permeable pipe body are distributed in a plum blossom shape, with an area opening rate of 10% to 20%. The pressure measuring tube is a prior art in this field and will not be described in detail here.

[0090] Embodiment 3

[0091] The structure and working principle of the automatic seepage monitoring system for rockfill dams described in the third embodiment are exactly the same as those described in the second embodiment. The purpose of the third embodiment is to provide a preferred structure of a pressure measuring tube.

[0092] The applicant has found that according to the on-site survey of the renovation construction, the changes in the in-service pressure measuring tubes after a period of time have shortened the effective measuring range and even lost the monitoring function. There are two reasons for this situation, one is the pressure measuring tube itself, and the other is the environment. For the reasons of the pressure measuring tube:

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

[0094] ② Electrochemical corrosion: usually occurs in the water surface boundary change area inside the pipe, where the dam body leakage is serious or in the low-lying area 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 implementation, a steel bar layer is provided between the outer wall of the piezometer and the non-woven geotextile, and a plurality of annularly distributed steel bars are welded to the outer wall of the piezometer, and then the non-woven geotextile is wrapped. Specifically, the steel bars are made of 1Cr15Ni4Mo3N steel, the length of which is adapted to the permeable pipe section, and a boride cladding layer, thermally sprayed aluminum and sealing paint are provided after welding. On the one hand, the steel bars enhance the structural strength of the piezometer and reduce the bending of the pipe body or pipe section caused by the environment.

[0103] Embodiment 4

[0104] The structure and working principle of the automated seepage monitoring system for rockfill dams described in the fourth embodiment are exactly the same as those described in the first embodiment. The piezometer monitoring subsystem described in the fourth embodiment also includes a plurality of buried piezometer devices connected to a data acquisition instrument.

[0105] There are two methods of burying vibrating-string piezometers that are often used when constructing a seepage monitoring system. One is to install it in a borehole. This method is more commonly used in buildings such as built reservoir dams. The other is to dig a pit on the dam body and fill for burying and installing. This method is suitable for completing the installation of the piezometer before construction when the reservoir dam is being constructed. Bury the piezometer during the dam body filling process: measure and lay out → excavate pits → bury the instrument → lay cables. During the cable laying process, the cable trench is excavated so that the cable of the piezometer is laid in an S shape. The present invention uses a plurality of borehole piezometer devices and a plurality of pit-buried piezometer devices to coordinate measurements to obtain more comprehensive sampling data; on the other hand, a borehole piezometer device or a pit-buried piezometer device can be selected according to actual needs.

[0106] like Figure 3 As shown, the buried piezometer device includes a 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 placed in a fine sand bag filled with fine sand of 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 two ends connected, 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] The applicant has found through research that the second piezometer buried in the clay core wall may be affected by the rolling of the core wall, causing the piezometer structure to produce strain, thereby affecting the accuracy and reliability of the piezometer measurement; in addition, the soil and rock pressure on the upper part of the rockfill dam is relatively large, which may also affect the piezometer sensor. To this end, the present invention provides a protective structure for the second piezometer by equipping the second piezometer with a protector without affecting the measurement of the second piezometer, thereby greatly reducing the impact of the core wall rolling on the second piezometer and the impact of the soil and rock pressure of the rockfill dam, thereby improving the measurement accuracy and reliability of the piezometer.

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

[0109] In a preferred implementation, 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; the outer surface of the steel mesh cage is provided with a thermally sprayed aluminum layer and a sealing paint layer. For details of the boride cladding layer, please refer to the description of Example 3.

[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 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. The outer surface of the pressure measuring tube is formed with corrosion resistance that is superior to that of 304 stainless steel tubes, and the anti-corrosion system that improves the service life of the protector is provided with a long-term protection effect for the protector, extending its service life and ensuring the accuracy and stability of the automated measurement.

[0111] Specifically, the buried piezometer device also includes an outer protective tube 40 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 hot-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.

[0112] Under the action of loads such as deadweight, water pressure and temperature, the dam will produce corresponding deformation, including vertical displacement of the surface. On the other hand, this property of the rockfill body enables it to complete most of the settlement deformation of the rockfill dam during the construction period and the first water storage period, and the remaining settlement is basically completed within 3 years of operation. By forming a gap between the outer protective pipe and the protector without contacting each other, and filling the gap with fine sand, a buffer space is formed between the outer protective pipe and the protector, which can better provide protection for the second piezometer, transfer the impact of the core wall rolling and the earth and rock pressure of the rockfill dam to the protection structure composed of the outer protective pipe and the protector, and place the second piezometer inside the outer protective pipe and the protector, which greatly reduces the impact of the core wall rolling and the earth and rock pressure of the rockfill dam on the second piezometer, thereby improving the measurement accuracy and reliability of the piezometer.

[0113] Embodiment 5

[0114] The structure and working principle of the automatic seepage monitoring system for rockfill dams described in the fifth embodiment are exactly the same as those described in the first embodiment. The fifth embodiment specifically describes the implementation of the weir monitoring subsystem and the fiber Bragg grating monitoring subsystem.

[0115] Wherein, the water measuring weir monitoring subsystem includes:

[0116] 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;

[0117] a water measuring weir meter, which is arranged in the inner concave vertical groove;

[0118] A second industrial gateway is connected to the water measuring weir meter, and the second industrial gateway is wirelessly connected to the monitoring background;

[0119] A water retaining cover is arranged above the water measuring weir meter and the second industrial gateway to block rainwater.

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

[0121] The main improvement of the present invention is that a water retaining cover is provided above the water measuring weir meter and the second industrial gateway to block rainwater. The water retaining cover is a "human" shaped structure, formed by integral injection molding of epoxy resin, or it can be formed by bending a stainless steel plate. The water retaining cover is fixed to the upper surface of the water measuring weir through a frame. The frame is a hollow cubic frame formed by welding a number of stainless steel square tubes. The water retaining cover is fixed to the top of the frame, and a water retaining plate can be provided on the side wall of the frame. Through this design, it is ensured that the water measuring weir meter does not directly contact rainwater, thereby ensuring the accuracy and reliability of the instrument measurement.

[0122] 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 a rate of 100 m / piece along the seams around the rockfill dam;

[0124] 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 optical 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 uses heating of optical fiber and then determines leakage by analyzing the temperature difference in the monitoring area. Its 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 this field and will not be described in detail here.

[0126] Specifically, when the fiber grating temperature sensor senses changes in the remote measurement, 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, and is mainly responsible for modulating and demodulating the optical signal returned by the sensor, converting physical quantity data, and calculating the signal; 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, performs early warning identification and judgment on the identification data according to the early warning rule parameters, and performs information synthesis and superposition processing on the identification data, optical fiber information data, early warning information data, target location information, etc., and performs communication protocol conversion and wireless transmission.

[0127] Project Examples

[0128] This project takes the upgrade and transformation of the automated monitoring system of a reservoir dam in Guangzhou as an example, and provides an example of the deployment of the piezometer monitoring subsystem of the automated seepage monitoring system for rockfill dams.

[0129] The dam site of a certain reservoir is located in the downstream of Fentianshui, a tributary of Liuxi River. It is a medium-sized reservoir mainly used for irrigation, combined with flood control, power generation and other comprehensive utilization. The reservoir dam is designed according to a flood that occurs once in 100 years and verified for a flood that occurs once in 1000 years. The catchment area is 92.3KM2, the average annual rainfall is 1995mm, the total storage capacity is 90.97 million square meters, the average annual inflow is 102.04 million m3, and the average annual outflow is 96.63 million m3. The dead water level of the reservoir is 139.91m, and the corresponding storage capacity is 2.4 million m3; the normal water level (flood limit water level) is 175.01m (Pearl Base, the same below), and the corresponding storage capacity is 82.89 million m3; the design flood level is 175.85m, and the corresponding storage capacity is 86.98 million m3; the verified flood level is 176.44m, and the corresponding storage capacity is 90.97 million m3.

[0130] The main buildings include the main dam, spillway, power station and water transfer tunnel. The main dam is a mortar-stone gravity dam with a length of 181.9m, a maximum height of 61.3m and a crest width of 5m. The spillway is equipped with two spillway gates, two 8m×7m steel arc gates, and two 25t single-drum double-point winches for opening and closing. The designed discharge flow is 765m3 / s. The project has been operating normally since its completion, giving full play to the social, economic and ecological benefits of irrigation, flood control and power generation.

[0131] (1) System composition:

[0132] The system consists of a three-level network of measurement and control network, local area network and remote Internet, connecting the on-site measurement and control layer, engineering management layer and upper management layer, forming a monitoring, management and multi-level decision support system. Figure 1 The architecture is set.

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

[0134] The dam is equipped with 4 sets of telemetered lysimeters, which are used to measure the leakage of the dam body or dam foundation. The leakage of the left bank dam foundation is measured by a telemetered lysimeter arranged at the left bank foundation corridor at an elevation of ▽130m; the leakage of the right bank dam foundation is measured by a telemetered lysimeter arranged at the right bank foundation corridor at an elevation of ▽140m; the leakage of the dam foundation below the elevation of ▽130m on the left bank and below the elevation of ▽140m on the right bank is measured by a telemetered lysimeter arranged at the entrance of the corridor at an elevation of ▽121m; the leakage of the dam body is measured by a telemetered lysimeter arranged in the corridor at an elevation of ▽127.

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

[0136] A reservoir dam has 11 piezometers buried along the entire longitudinal corridor from the left bank at an elevation of 152m to the horizontal section at an elevation of 127m, and then to the right bank at an elevation of 147m. Four piezometers are buried along the foundation corridor at an elevation of 121m to test the uplift pressure of the dam foundation. The original piezometers are aging and unstable, and this project plans to replace all 15 piezometers.

[0137] Imported GK-4500S standard piezometer is used to measure fluid pressure. For example, it can be buried in dam bodies or fill to monitor groundwater levels and pore water pressure. It can also be installed in boreholes, observation wells or pressure measuring tubes.

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

[0139] Sensor type: vibrating wire;

[0140] Model: GK-4500S;

[0141] Measuring range: 0.35MPa (foundation behind the anti-seepage body, dam body, and inside the pressure measuring tube), 1.0MPa (before the anti-seepage body);

[0142] Sensitivity: 0.025% FS;

[0143] Non-linearity: ≤0.1%FS;

[0144] Temperature range: -20℃~80℃.

[0145] Calibration time: 10 years.

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

[0147] Material selection of the pressure measuring tube: the pressure measuring tube of the third embodiment of the present invention is adopted. The pressure measuring tube is made of 1Cr15Ni4Mo3N steel, and a boride cladding layer, thermally sprayed aluminum and sealing paint are arranged on the outer surface of the pressure measuring tube.

[0148] (4) Seepage around the dam:

[0149] The reservoir currently only has a dam foundation uplift pressure monitoring project, but no bypass seepage monitoring project is set up on the two dam shoulders. The junction of the two dam shoulders of the reservoir is often the weak link of the dam and is prone to danger. Therefore, it is necessary to add a bypass seepage monitoring project to conduct a comprehensive and complete monitoring of the seepage conditions of the dam.

[0150] The size and distribution of the bypass seepage are mainly related to the geological characteristics of the two dam shoulders, the degree of cracks, the quality of curtain grouting, the effect of the drainage system, etc. According to the specific conditions of the dam, along the junction of the two dam shoulders, from the dam top to the downstream side of the foundation grouting gallery, 5 holes (1 section) of bypass seepage pressure measuring tubes are set respectively, with a total of 10 measuring points. The pressure measuring tube adopts the pressure measuring tube of the third embodiment of the present invention.

[0151] The imported GK-4500S standard piezometer is used to measure fluid pressure. For example, it can be buried in a dam or fill to monitor groundwater level and pore water pressure. It can also be installed in a borehole, observation well or pressure measuring tube.

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

[0153] Sensor type: vibrating wire;

[0154] Model: GK-4500S;

[0155] Measuring range: 0.35MPa (foundation behind the anti-seepage body, dam body, and inside the pressure measuring tube), 1.0MPa (before the anti-seepage body);

[0156] Sensitivity: 0.025% FS;

[0157] Non-linearity: ≤0.1%FS;

[0158] Temperature range: -20℃~80℃.

[0159] Calibration time: 10 years.

[0160] 4.2 The technical indicators of the pressure measuring tube are as follows:

[0161] Selection of measuring tube material: The measuring tube of the third embodiment of the present invention is used. The measuring tube is made of 1Cr15Ni4Mo3N steel, and a boride cladding layer, thermal sprayed aluminum and sealing paint are arranged on the outer surface of the measuring tube. For other structures of the automatic seepage monitoring system for rockfill dams described in this embodiment, refer to the prior art.

[0162] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An automated seepage monitoring system for rockfill dams, characterized in that: It includes a piezometer monitoring subsystem and a monitoring background based on wireless network connection communication; The osmometer monitoring subsystem includes a first industrial gateway, a data acquisition instrument and a plurality of borehole osmometer devices connected in sequence; the first industrial gateway is wirelessly connected to the monitoring background, and the borehole osmometer device includes: A pressure measuring tube is adapted to be inserted into a borehole at a measuring point. The pressure measuring tube is made of 1Cr15Ni4Mo3N steel. A plurality of annularly distributed steel bars are welded to the outer wall of the pressure measuring tube. The steel bars are made of 1Cr15Ni4Mo3N steel. The pressure measuring tube is coated with a non-woven geotextile. The outer surface of the pressure measuring tube is sequentially provided with a boride cladding layer, a thermally sprayed aluminum layer and a sealing paint layer. A filler part, which is filled in the pressure measuring tube; A first osmometer, which is buried in the filler part, wherein a cable of the first osmometer extends from the upper part of the pressure measuring tube and is connected to a data acquisition instrument; The boride cladding layer is a ternary boride metal ceramic cladding layer prepared on the surface of the pressure measuring tube by plasma cladding technology; the cladding powder for preparing the boride cladding layer is composed of the following raw materials in percentage by mass: Mo35.0%, B8.0%, Si 1.0%, Cr 10.0%, C 0.5%, Ni 2.0%, and the balance is Fe; The osmometer monitoring subsystem also includes a plurality of buried osmometer devices connected to the data acquisition instrument, and the buried osmometer devices include: Fine sand filling material, which is filled in the buried pit of the measuring point; A second osmometer is placed in a fine sand bag filled with fine sand having a particle size not greater than 2 mm, wherein the fine sand bag is completely wrapped by the fine sand filler; The protector is a hollow tubular structure with two ends connected, and the protector is horizontally buried in the fine sand filling material; The fine sand bag wrapping the second osmometer 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; 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; 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 gap between the steel mesh cage and the inner steel pipe and the outer steel pipe is filled with fine sand. 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; the cladding powder of the boride cladding layer of the inner steel pipe and the outer steel pipe is composed of the following raw materials in percentage by mass: Mo35.0%, B8.0%, Si 1.0%, Cr 10.0%, C 0.5%, Ni 2.0%, and the balance is Fe; The outer surface of the steel mesh cage is provided with a thermal sprayed aluminum layer and a sealing paint layer.

2. The automatic seepage monitoring system for rockfill dam according to claim 1 is characterized by: The filler 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; The first piezometer is loaded into a fine sand bag filled with fine sand having 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 is characterized by: 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 is characterized by: 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, 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, 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 optical fiber information data, warning information data, and target position information, and sends them to the third industrial gateway.

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