Dam inverted vertical hole construction method and matched automatic monitoring system thereof

Abstract

The invention discloses a dam inverted hole construction method and a matched automatic monitoring system thereof, belongs to the field of water conservancy projects, and aims to solve the problems of insufficient inverted hole construction precision, large monitoring system error, poor compatibility and the like in the prior art. The construction method comprises the steps that gallery facilities are dismantled, and a site is cleaned to determine the drilling position; a YL-6 type drilling machine is adopted to be matched with a special drill rod and a centralizer, the hole diameter of an open hole is controlled to range from phi 220 mm to phi 325 mm, the effective hole diameter of a final hole is larger than or equal to 175 mm, inclination measurement is conducted every 1-2 m, and inclination correction is conducted when the hole inclination reaches 22 mm; and a phi 168 * 8mm seamless steel pipe is selected as a protection pipe and is buried after being pre-assembled and detected, so that the effective aperture after the cement paste is solidified is not less than 110mm. A matched monitoring system is provided with a high-precision photoelectric plumb line coordinatograph, data is processed through multi-parameter algorithms such as temperature drift correction, dynamic error compensation and coordinate conversion, automatic and manual check values are integrated in combination with a data fusion strategy, and an RS-485 interface and daisy chain topology are adopted to be in butt joint with an existing DSIMSV4.0 system. The construction precision and the monitoring reliability are improved.

Description

Technical Field

[0001] The technology belongs to the field of water conservancy engineering, and in particular, it is a method for constructing inverted holes in dams and its supporting automated monitoring system. Background Technology

[0002] As the core of water conservancy projects, dams are directly related to major public needs such as flood control, power generation, and water supply. Deformation monitoring, a key means of assessing the structural stability of dams, relies on high-precision benchmark facilities and reliable monitoring systems. Inverted boreholes, as the core benchmark for dam deformation monitoring, allow for long-term and accurate monitoring of the vertical displacement and horizontal deformation of the dam body and foundation by installing a plumb line system within the borehole. The construction quality and the maturity of the supporting monitoring technologies directly affect the reliability of the monitoring data.

[0003] In the field of inverted hole construction, existing technologies face multiple challenges. Complex geological conditions, such as uneven rock strata, fracture development, and insufficient drill bit stability, make it difficult to control drilling accuracy, frequently resulting in excessive borehole inclination and affecting the installation accuracy of subsequent plumb line systems. For example, traditional elastic centering devices are prone to torsion and deformation due to friction and rotation in practical applications, significantly reducing measurement accuracy and even causing equipment damage. The shortcomings of the protective pipe installation process are also prominent; improper control of its straightness, inclination value, and gap with the borehole wall can introduce additional measurement errors. Although some projects employ technologies such as borehole guide pipes and timed inclination measurement, such as the Jiangya Dam project using the XY4 drilling rig...

[0004] The DZ2 inclinometer achieves borehole deviation control of 0.58‰, but different projects lack unified standards in equipment selection and timing of deviation correction, resulting in inconsistent construction quality.

[0005] The limitations of automated monitoring systems are also significant. Traditional systems rely on manual calibration and limited monitoring points, making it difficult to achieve comprehensive risk perception. For example, the impact of temperature drift on displacement measurements is not effectively compensated, and conversion errors between the instrument coordinate system and the engineering coordinate system lead to mismatches between the data and the actual coordinate system. In terms of data fusion, existing systems often lack dynamic weight allocation mechanisms, failing to fully combine the advantages of automated measurements and manual verification. Furthermore, system compatibility issues are prominent, with problems such as incompatibility with existing monitoring platform communication protocols and unreasonable wiring topologies increasing the difficulty of long-term maintenance.

[0006] With the development of technologies such as the Internet of Things and big data, emerging monitoring methods are bringing about changes in the industry. Intelligent sensing networks, through devices such as GNSS positioning systems and fiber optic sensors, construct multi-dimensional monitoring systems capable of capturing millimeter-level deformation and seepage anomalies in real time. Digital twin technology, by integrating design, construction, and real-time monitoring data, enables full life-cycle simulation of dam operation, significantly improving risk prediction capabilities. However, existing systems still face bottlenecks in data quality, model complexity, and technical standards. For example, sensor failures, data transmission interference leading to information distortion, and a lack of unified industry standards to guide the construction of digital twin models are all challenges.

[0007] The updating of industry standards further highlights the urgency of technological upgrades. The "Technical Specifications for Monitoring Small Reservoirs" and the "Technical Specifications for Safety Monitoring of Earth-Rock Dams," released in 2024, emphasize the importance of automated monitoring, digital twin collaboration, and an integrated "sky-ground-hydraulic" sensing system, requiring improvements in the redundant deployment and real-time analysis capabilities of monitoring systems. Against this backdrop, developing standardized construction methods and high-precision, high-stability monitoring systems has become a key measure to meet the long-term safety monitoring needs of dams. Summary of the Invention

[0008] This invention provides a method for constructing inverted boreholes in dams and a corresponding automated monitoring system. By providing a standardized method for constructing inverted boreholes in dams and a supporting high-precision, high-stability automated monitoring system, it achieves accurate monitoring and reliable data support for dam deformation, thereby ensuring the safe operation of the dam. The technical solution to the above-mentioned technical problems is as follows:

[0009] A method for constructing a dam inverted hole and its supporting automated monitoring system, wherein the method for constructing the inverted hole includes the following steps:

[0010] (1) Demolish the corridor passage door and the wall of the vertical line room, clean up the construction site, and determine the drilling location and pile number;

[0011] (2) Use YL6 type engineering drilling rig, with special drill rod and stabilizer, the hole diameter is Ф220mm to Ф325mm, and the effective hole diameter after drilling is ≥175mm; during the drilling process, use elastic guide and float group to measure the inclination every 1 to 2m, and correct the inclination when the hole inclination is not less than 22mm.

[0012] (3) Select Ф168×8mm seamless steel pipe as protective pipe. After pre-installation and testing, weld the bottom and process a rough surface of 0.2m. Inject cement slurry into the bottom of the hole to a height of not less than 0.5m. Lower the protective pipe to the bottom of the hole and fix it. After the cement slurry solidifies, test its effective hole diameter ≥110mm.

[0013] As a preferred technical solution of the present invention, the straightness error of the special drill rod in step (2) is ≤0.5mm / m, the thread fit accuracy is first grade, the stabilizer is selected including but not limited to Ф168, Ф219 and Ф250 models, and the diamond drill bit parameters are: matrix hardness HRC35~40, diamond concentration 75%~100%.

[0014] As a preferred technical solution of the present invention, the installation of the protective pipe in step (3) further includes: measuring the deviation value of the protective pipe every 0.5m, calculating the pipe wall gap at 45° intervals of each section, obtaining the spacing and height of the stainless steel support points, and ensuring that the straightness of the pipe section is ≤1.0mm.

[0015] 4. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that the inclination measurement method in step (2) is as follows: a coordinate system is established at the hole opening, where the left bank in the X direction is positive and the downstream in the Y direction is positive. The vertical line is kept vertical by the buoyancy of the float. The deviation of the vertical line from the center point is measured every 0.5m back and forth to determine the position of the support point.

[0016] A method for constructing inverted boreholes in a dam and its supporting automated monitoring system, wherein the automated monitoring system collects raw data through equipment configuration, corrects and integrates the data through a data processing module, and achieves data interaction with external systems through system integration, specifically including:

[0017] (1) Includes one photoelectric vertical coordinate instrument with a measurement error ≤0.1mm and a resolution ≤0.01mm, a data acquisition module, a temperature sensor and a communication line;

[0018] (2) After removing the old equipment, fix the coordinate instrument to the stainless steel bracket, connect it to the data acquisition module through a four-core shielded cable, and use a calibration rack and dial indicator to calibrate the forward and reverse strokes in multiple ranges.

[0019] (3) An integrated multi-parameter correction algorithm, including:

[0020] ① Based on the difference between the real-time temperature and the calibration reference temperature, the original measured value is corrected to eliminate the drift effect caused by temperature changes. The correction amount is 0.002 mm for every 1°C deviation of the temperature from the reference temperature.

[0021] ② Taking into account the short-term fluctuations and long-term drift caused by the measurement interval, error compensation is performed on the measured value. The compensation amount is the sum of the product of the short-term fluctuation coefficient and the first power of the measurement interval, and the product of the long-term drift coefficient and the square power of the measurement interval. The compensated displacement is obtained by subtracting this sum from the measured value.

[0022] ③ Based on the instrument installation deflection angle and the offset of the coordinate origin, convert the coordinates in the instrument's own coordinate system to the coordinates in the dam engineering coordinate system. During the conversion, the instrument coordinates need to be calculated by combining the sine and cosine values ​​of the deflection angle, and then the offset of the origin is added.

[0023] (4) Data fusion: The final displacement value is obtained by combining automated measurement and manual verification values. The weight of each is determined according to their respective measurement accuracy. The higher the accuracy, the greater the weight.

[0024] (5) It interfaces with the existing DSIMSV4.0 automation system, using an RS485 communication interface and a daisy-chain topology, and achieves data interaction through a preset displacement calculation formula.

[0025] As a preferred technical solution of the present invention, the calibration steps of the automated monitoring system are as follows: fix the vertical line at the -25, -12.5, 0, 12.5, 25mm groove positions of the calibration frame push block, fix the dial indicator by the magnetic dial indicator frame, complete no less than 3 forward and reverse stroke measurements in the left and right banks and upstream and downstream directions, and calculate the linear error, hysteresis and repeatability error.

[0026] As a preferred technical solution of the present invention, the debugging of the data acquisition module includes: initializing the measurement point group information, including but not limited to module address, channel number and other information; setting the timed measurement cycle; and putting it into use after running continuously for 48 hours without failure. The communication cable is an RVYSP4×0.5 or higher twisted pair cable, and the power line is an RVVP2×2.5 or higher and is equipped with an independent air circuit breaker.

[0027] As a preferred technical solution of the present invention, the preset displacement calculation formula is: upstream and downstream displacement = [A] - 25.160, left and right bank displacement = 27.570 - [B], where [A] is the original measured value in the upstream and downstream direction, and [B] is the original measured value in the left and right bank direction.

[0028] As a preferred technical solution of the present invention, the automated monitoring system also includes a cable identification mechanism: signs are hung at both ends of the cable and in the middle of the protective pipe, wiring diagrams are set in the equipment box and DAU box, and the communication link is in daisy chain topology, with branching devices installed at the branch points.

[0029] As a preferred embodiment of the present invention, in the parameter correction algorithm, the short-term fluctuation coefficient and the long-term drift coefficient are determined in the following way: the short-term fluctuation coefficient decreases exponentially with the increase of system runtime, and the decay rate is determined by the short-term decay time constant and the proportional coefficient; the long-term drift coefficient gradually tends to a stable value with the increase of system runtime, and the stabilization rate is determined by the long-term stabilization time constant and the proportional coefficient.

[0030] Calibration of instrument installation deflection angle: Determine the deflection angle of the instrument during installation by comparing the angle between the line connecting two reference points in the engineering coordinate system and the angle between the line connecting the two points measured by the instrument.

[0031] In data fusion algorithms, the standard deviation is calculated as follows: The standard deviation of automated measurements reflects the dispersion of multiple measurements taken by an automated system. It is obtained by taking the square root of the sum of the squares of the deviations of each measurement from the average value and the number of measurements. The standard deviation of manual measurements reflects the dispersion of multiple manual verification values. It is obtained by taking the square root of the sum of the squares of the deviations of each verification value from the average value and the number of verifications.

[0032] The beneficial effects of adopting the above technical solution are as follows: Standardized inverted hole construction procedures effectively improve the construction accuracy and stability of the inverted holes, providing a reliable benchmark for subsequent monitoring; the supporting automated monitoring system, through high-precision equipment configuration, multi-parameter correction algorithms, and scientific data fusion strategies, significantly improves the accuracy and reliability of deformation monitoring data; at the same time, through compatibility with existing systems and standardized cable identification mechanisms, the system's compatibility, stability, and maintenance convenience are enhanced, ultimately achieving accurate and efficient monitoring of dam deformation and providing strong data support for the safe operation of the dam. Attached Figure Description

[0033] Figure 1 Show a site condition diagram before construction;

[0034] Figure 2 : Structural diagram of inclinometer equipment;

[0035] Figure 3 Anti-tilt equipment selection diagram;

[0036] Figure 4 Calibration steps Figure 1 ;

[0037] Figure 5 Calibration steps Figure 2 ;

[0038] Figure 6 Calibration steps diagram;

[0039] Figure 7 Standardized flowchart;

[0040] Figure 8 System stability diagram;

[0041] Figure 9 Cable management standard diagram. Detailed Implementation

[0042] The following embodiments detail the present invention. In the description of these embodiments, specific details such as particular system structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail. Content already reflected in previous embodiments is assumed to be present in subsequent embodiments.

[0043] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0044] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0045] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0046] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0047] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0048] Example 1: Technical Explanation

[0049] To provide a standardized method for constructing inverted boreholes in dams and a corresponding high-precision, high-stability automated monitoring system, enabling accurate monitoring and reliable data support for dam deformation to ensure safe dam operation, this invention achieves this through the following methods.

[0050] Construction steps: Demolish the corridor passage door and the wall of the vertical line chamber, clean the construction site, and determine the drilling location and station number; use a YL6 type engineering drilling rig, with special drill rods and a centralizer, to open the hole with a diameter of Ф220mm to Ф325mm, and ensure that the effective hole diameter is ≥175mm after drilling; establish a coordinate system at the hole opening, with the left bank of the X direction as positive and the downstream of the Y direction as positive, and use the buoyancy of the float to keep the vertical line vertical, measuring the deviation of the vertical line from the center point coordinate every 0.5m back and forth to determine the position of the support point; during the drilling process, use an elastic center guide and float group to measure the inclination every 1-2m, and correct the inclination when the hole inclination is not less than 22mm; select Ф168×8mm seamless steel pipe as the protective pipe, pre-install and test it, weld the bottom and process a 0.2m rough surface, inject cement grout into the bottom of the hole to a height of not less than 0.5m, lower the protective pipe to the bottom of the hole and fix it, and after the cement grout solidifies, check that its effective hole diameter is ≥110mm.

[0051] Selection of construction equipment and materials: The straightness error of the special drill rod during construction is ≤0.5mm / m, the thread fit accuracy is Grade 1, the stabilizer is selected including but not limited to Ф168, Ф219 and Ф250 models, and the diamond drill bit parameters are: matrix hardness HRC35~40, diamond concentration 75%~100%, and the deviation value of the protective pipe is measured every 0.5m, the pipe wall gap at 45° intervals of each section is calculated, the spacing and height of the stainless steel support points are obtained, and the straightness of the pipe section is ≤1.0mm;

[0052] The supporting automated testing system: Raw data is collected through equipment configuration, corrected and integrated by the data processing module, and then exchanged with external systems through system integration. Specifically, this includes:

[0053] (1) Includes one photoelectric vertical coordinate instrument with a measurement error ≤0.1mm and a resolution ≤0.01mm, a data acquisition module, a temperature sensor and a communication line;

[0054] (2) After removing the old equipment, fix the coordinate instrument to the stainless steel bracket, connect it to the data acquisition module through a four-core shielded cable, and use a calibration rack and dial indicator to calibrate the forward and reverse strokes in multiple ranges.

[0055] (3) An integrated multi-parameter correction algorithm, including:

[0056] ① Corrected displacement value = original measured value - κ × (T - T0), where κ is the temperature coefficient: 0.002 mm / ℃, T is the real-time temperature, and T0 is the calibration reference temperature: 20℃;

[0057] ② Displacement after compensation = Measured value - ∑(αi×Δt) i (i = 1, 2), where α1 is the short-term fluctuation coefficient, α2 is the long-term drift coefficient, and Δt is the measurement interval;

[0058] ③ Convert the instrument coordinate system (X',Y') to the dam engineering coordinate system (X,Y): X=X'×cosθ-Y'×sinθ+X0,Y=X'×sinθ+Y'×cosθ+Y0,where θ is the instrument installation deflection angle, and X0 and Y0 are the offset of the coordinate origin;

[0059] (4) Perform data algorithm fusion, and the final displacement value = ω1 × automated measurement value + ω2 × manual verification value, where ω1 = σ2 2 / (σ1 2 +σ2 2 ), ω2=σ1 2 / (σ1 2 +σ2 2 ), where σ1 is the standard deviation of automated measurement and σ2 is the standard deviation of manual measurement;

[0060] (5) It interfaces with the existing DSIMSV4.0 automation system, using an RS485 communication interface and a daisy-chain topology, and achieves data interaction through a preset displacement calculation formula.

[0061] System operation steps: Fix the plumb line at the 25, 12.5, 0, 12.5, and 25mm groove positions on the calibration frame push block. Fix the dial indicator with the magnetic holder. Perform no less than 3 forward and reverse stroke measurements in the left and right banks and upstream and downstream directions. Calculate the linearity error, hysteresis, and repeatability error. Initialize the measurement point group information, including but not limited to module address and channel number information. Set the timed measurement cycle. After 48 hours of continuous operation without failure, put it into use. The communication cable should be RVYSP4×0.5 or higher twisted pair cable, and the power cable should be RVVP2×2.5 or higher with an independent air circuit breaker.

[0062] Partial System Operating Principles and Requirements: Upstream and downstream displacement = [A] - 25.160, left and right bank displacement = 27.570 - [B], where [A] is the original measurement value in the upstream and downstream direction, and [B] is the original measurement value in the left and right bank direction; Labels are hung at both ends of the cable and in the middle of the protective pipe; wiring diagrams are installed in the equipment box and DAU box; the communication link follows a daisy-chain topology, and splitters are required at branch points; the short-term fluctuation coefficient α1 and the long-term drift coefficient α2 are determined as follows: α1 = k1 × e^(-t / τ1), α2 = k2 × (1 - e^(-t / τ2)), where k1 and k2 are proportionality coefficients, τ1 is the short-term decay time constant, τ2 is the long-term stability time constant, and t is the system running time; the calibration formula for the instrument installation deflection angle θ is: θ = arctan[(Y2- Y1) / (X2-X1)]-arctan[(Y'2-Y'1) / (X'2-X'1)], where (X1,Y1) and (X2,Y2) are the coordinates of two reference points in the engineering coordinate system, and (X'1,Y'1) and (X'2,Y'2) are the measured coordinates of the instrument; in the coordinate transformation formula, the calibration formula for the instrument installation deflection angle θ is: θ=arctan[(Y2-Y1) / (X2-X1)]-arctan[(Y'2-Y'1) / (X'2-X'1)], where (X1,Y1) and (X2,Y2) are the coordinates of two reference points in the engineering coordinate system, and (X'1,Y'1) and (X'2,Y'2) are the measured coordinates of the instrument; in the data fusion algorithm, the standard deviations σ1 and σ2 are obtained through real-time calculation: Where x i Let μ1 be the mean of n measurements taken by the automated system; y i Let μ be the value of m manual verifications, and μ2 be its mean.

[0063] Example 2: Restoration Project of Inverted Hole in Section 1 of Wanjiazhai Hydropower Station

[0064] I. Detailed Construction Process of Inverted Hole

[0065] 1. Preliminary preparations, please refer to the appendix. Figure 1

[0066] Demolition work: Remove the 947.5m elevation corridor access gate and the upstream and downstream walls of the vertical line chamber of section 1 dam, and clear a 3m×4m construction area; remove the original upright and inverted vertical observation piers and steel supports, and move the old equipment to the designated warehouse.

[0067] Positioning and setting out: Determine the borehole center based on the station number "dam +065.90, down +014.75", and use a total station to calibrate the borehole position, with the error controlled within ±5mm.

[0068] 2. Drilling Equipment Configuration: A YL6A engineering drilling rig will be selected, equipped with dedicated drill rods with a straightness error ≤0.5mm / m. The stabilizer will be either Ф168 or Ф219. The diamond drill bit parameters are: matrix hardness HRC38, diamond concentration 85%. (Refer to the attached document.) Figure 2 and attached Figure 3 .

[0069] Drilling control: The initial borehole diameter was Ф220mm. At 20m, a rock fissure was encountered, and the borehole was temporarily enlarged to Ф325mm. The remaining sections maintained Ф220mm. Every 1.5m, an elastic guide and float assembly were used for inclination measurement (X-direction to the left bank and Y-direction downstream were positive in the borehole coordinate system). A total of 34 inclination measurements were taken, with 3 locations showing an inclination of 20mm, which were not corrected. The final borehole depth was 51m, and the effective borehole diameter was measured to be 178mm.

[0070] 3. For the installation of protective pipes, please refer to the attached document. Figure 4 and attached Figure 5

[0071] Pre-installation inspection: Ф168×8mm seamless steel pipe is selected. When pre-installing on flat ground, the axis is calibrated with a chalk line and the deviation is ≤0.8mm. After the bottom is welded and sealed, the inner wall of the lower 0.2m is processed into a rough surface to enhance the anchoring force of cement grout.

[0072] Bottom treatment: Inject C30 cement grout to a height of 0.5m into the bottom of the hole using a grouting pump to slowly inject the grout, ensuring no air bubbles are present; after lowering the protective pipe to the bottom of the hole, tighten it with a jack (the top should be 300mm above the hole opening).

[0073] Deviation monitoring: During the cement grout solidification period, the deviation of the protective pipe was measured every 0.5m, for a total of 102 cross-sections. Among them, the deviation in the X direction was 3mm and the deviation in the Y direction was +2mm at a hole depth of 10m. The pipe wall gap at 45° intervals was calculated to be 8-12mm, and the spacing of the stainless steel support points was determined to be 1.5m and the height was 5mm.

[0074] Final test: After the cement grout solidified, the effective diameter of the protective pipe was measured using a borehole gauge. The minimum effective diameter at a depth of 50m was 132.65mm.

[0075] II. Installation and Commissioning of Automated Monitoring System

[0076] III.1. Equipment Selection and Removal

[0077] New equipment configuration: NGDZ50 photoelectric vertical coordinate instrument: measurement error 0.08mm, resolution 0.01mm, NDA93 data acquisition module, RVYSP4×0.5 twisted pair communication cable, RVVP2×2.5 power cord.

[0078] Removal of old equipment: Remove the original plumb line coordinate instrument and steel bracket, clean the cable trough, and install a new 304 stainless steel bracket (800mm×600mm×500mm) at the original observation pier location, with a horizontality error ≤0.1mm / m.

[0079] 2. Calibration and calibration, refer to the appendix. Figure 6

[0080] Instrument calibration: Using a dedicated calibration stand (including -25, -12.5, 0, 12.5, and 25 mm grooves), a 0.01 mm precision dial indicator was fixed in a magnetic stand. Three forward and reverse stroke measurements were performed on both the left and right banks (Y direction) and upstream and downstream (X direction). The linearity error in the X direction was 0.04 mm, the hysteresis was 0.02 mm, and the repeatability error was 0.01 mm.

[0081] Coordinate transformation calibration: Select the engineering coordinate system reference points (X1=947.500m, Y1=065.900m; X2=947.500m, Y2=066.900m), the instrument measured coordinates (X'1,Y'1) and (X'2,Y'2), the deflection angle θ=0.3° was calculated, and the coordinates were substituted into the transformation formula to achieve coordinate system matching.

[0082] 3. System Integration and Testing

[0083] Communication cable deployment: The communication cable is laid in a daisy chain topology, with a dedicated splitter installed at the branch point, and a sign hanging at both ends (marked "1 drooping X / Y"). The wiring diagram is posted inside the DAU box.

[0084] Software integration: Connect to the DSIMSV4.0 system, set the timed measurement cycle to 30 minutes, initialize the module address NDA93 and channels 15 (X direction) and 16 (Y direction), and preset the displacement formula "upstream and downstream displacement = [A] - 25.160; left and right bank displacement = 27.570 - [B]".

[0085] Stability test: After 48 hours of continuous operation, a total of 192 sets of data were collected, with a data integrity rate of 100%. The deviation from the manually verified value was ≤0.05mm, which meets the 16 test qualification standards in Table 52, including "Instrument Continuous Measurement Stability" and "MCU Communication".

[0086] III. Project Acceptance Results

[0087] It was put into trial operation on August 27, 2019. The effective diameter of the inverted hole, the deflection of the protective pipe, and the measurement accuracy of the system all meet the requirements of the "Technical Specification for Safety Monitoring of Concrete Dams" (SL6012013). Among them, the error between the automated monitoring data and the manual comparison is ≤0.1mm, which meets the design target.

[0088] Example 3: A high dam project, see attached document. Figure 7

[0089] 1. Implementation of dynamic error compensation: In the initial stage of system operation (t = 2h), the short-term fluctuation coefficient α1 = k1 × e^(2 / 2) = 0.368k1, and the long-term drift coefficient α2 = k2 × (1e^(2 / 72)) = 0.027k2. After compensating for the original value of the measurement interval Δt = 1h, the error is reduced by 40%.

[0090] 2. Data Fusion Application: The mean of automated measurements (n=10 times) is μ1=25.162mm, and the standard deviation σ1=0.03mm; the mean of manually verified measurements (m=5 times) is μ2=25.165mm, and the standard deviation σ2=0.05mm. The calculation weights are ω1=64% and ω2=36%, resulting in a final displacement value of 25.163mm. The accuracy is improved by 32% after fusion. (See attached figure for reference.) Figure 8 .

[0091] Example 4: Control of Protective Pipe Installation Accuracy

[0092] During the construction of the inverted shaft of a gravity dam, the requirement in the main document to "measure the deviation of the protective pipe every 0.5m" was strictly followed.

[0093] At a hole depth of 25m, the X-direction deviation was measured to be +5mm and the Y-direction deviation to be 3mm. The calculated pipe wall clearance at 45° angles was: 12mm at 0°, 10mm at 45°, 8mm at 90°, and 11mm at 135°. Based on this, the height of the stainless steel support points was determined to be 8mm (taking the minimum value), with a spacing of 1.0m, ensuring the pipe section straightness is ≤0.9mm (better than the ≤1.0mm requirement). After installation, a laser straightness meter was used to check that the overall straightness error of the hole was ≤1.5mm, meeting the requirements for non-contact vertical operation.

[0094] Example 5: Upgrade Project of Inverted Hole Monitoring System for a Water Conservancy Project

[0095] Equipment Wiring and Labeling. The communication cable uses RVYSP4×0.5 twisted-pair cable, with labels at both ends (labeled "PL1-1-X / Y Channel"). A wiring diagram is posted inside the DAU box. Dedicated branch switches are installed at branch points to avoid star-shaped twisted connections. See attached document. Figure 9 .

[0096] Dynamic error compensation: In the initial stage of system operation (t=2h), the short-term fluctuation coefficient α1=k1×e^(-2 / 2)=k1×0.368 and the long-term drift coefficient α2=k2×(1-e^(-2 / 72))≈k2×0.027 are used to eliminate the error caused by the measurement interval through the compensation formula.

[0097] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for constructing inverted boreholes in a dam and its supporting automated monitoring system, characterized in that, The method for constructing the inverted hole includes the following steps: (1) Demolish the corridor passage door and the wall of the vertical line room, clean up the construction site, and determine the drilling location and pile number; (2) Use YL6 type engineering drilling rig, with special drill rod and stabilizer, the hole diameter is Ф220mm to Ф325mm, and the effective hole diameter after drilling is ≥175mm; during the drilling process, use elastic guide and float group to measure the inclination every 1 to 2m, and correct the inclination when the hole inclination is not less than 22mm. (3) Select Ф168×8mm seamless steel pipe as protective pipe. After pre-installation and testing, weld the bottom and process a rough surface of 0.2m. Inject cement slurry into the bottom of the hole to a height of not less than 0.5m. Lower the protective pipe to the bottom of the hole and fix it. After the cement slurry solidifies, test its effective hole diameter ≥110mm.

2. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that, The straightness error of the special drill rod in step (2) is ≤0.5mm / m, the thread fit accuracy is first grade, the stabilizer is selected including but not limited to Ф168, Ф219 and Ф250 models, and the diamond drill bit parameters are: matrix hardness HRC35~40, diamond concentration 75%~100%.

3. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that, The installation of the protective pipe in step (3) also includes: measuring the deviation value of the protective pipe every 0.5m, calculating the pipe wall gap at 45° intervals in each section, obtaining the spacing and height of the stainless steel support points, and ensuring that the straightness of the pipe section is ≤1.0mm.

4. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that, The inclination measurement method in step (2) is as follows: establish a coordinate system at the orifice, with the left bank in the X direction being positive and the downstream in the Y direction being positive. Use the buoyancy of the float to keep the vertical line vertical. Measure the deviation of the vertical line from the center point every 0.5m back and forth to determine the position of the support point.

5. A method for constructing inverted boreholes in dams and its supporting automated monitoring system, characterized in that, The automated monitoring system collects raw data through equipment configuration, and after being corrected and integrated by the data processing module, it achieves data interaction with external systems through system integration, specifically including: (1) Includes one photoelectric vertical coordinate instrument with a measurement error ≤0.1mm and a resolution ≤0.01mm, a data acquisition module, a temperature sensor and a communication line; (2) After removing the old equipment, fix the coordinate instrument to the stainless steel bracket, connect it to the data acquisition module through a four-core shielded cable, and use a calibration rack and dial indicator to calibrate the forward and reverse strokes in multiple ranges. (3) An integrated multi-parameter correction algorithm, including: ① Based on the difference between the real-time temperature and the calibration reference temperature, the original measured value is corrected to eliminate the drift effect caused by temperature changes. The correction amount is 0.002 mm for every 1°C deviation of the temperature from the reference temperature. ② Taking into account the short-term fluctuations and long-term drift caused by the measurement interval, error compensation is performed on the measured value. The compensation amount is the sum of the product of the short-term fluctuation coefficient and the first power of the measurement interval, and the product of the long-term drift coefficient and the square power of the measurement interval. The compensated displacement is obtained by subtracting this sum from the measured value. ③ Based on the instrument installation deflection angle and the offset of the coordinate origin, convert the coordinates in the instrument's own coordinate system to the coordinates in the dam engineering coordinate system. During the conversion, the instrument coordinates need to be calculated by combining the sine and cosine values ​​of the deflection angle, and then the offset of the origin is added. (4) Data fusion: The final displacement value is obtained by combining automated measurement and manual verification values. The weight of each is determined according to their respective measurement accuracy. The higher the accuracy, the greater the weight. (5) It interfaces with the existing DSIMSV4.0 automation system, using an RS485 communication interface and a daisy-chain topology, and achieves data interaction through a preset displacement calculation formula.

6. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that, The calibration steps for the automated monitoring system are as follows: fix the plumb line at the -25, -12.5, 0, 12.5, and 25mm groove positions on the calibration frame push block, fix the dial indicator with the magnetic gauge holder, complete no less than 3 forward and reverse stroke measurements in the left and right banks and upstream and downstream directions, and calculate the linear error, hysteresis, and repeatability error.

7. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that, The debugging of the data acquisition module includes: initializing the measurement point group information, including but not limited to module address and channel number information; setting the timed measurement cycle; and putting it into use after 48 hours of continuous operation without failure. The communication cable is RVYSP4×0.5 or higher twisted pair cable, and the power line is RVVP2×2.5 or higher and equipped with an independent air circuit breaker.

8. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that, The preset displacement calculation formula is: upstream and downstream displacement = [A] - 25.160, left and right bank displacement = 27.570 - [B], where [A] is the original measured value in the upstream and downstream direction, and [B] is the original measured value in the left and right bank direction.

9. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that, The automated monitoring system also includes a cable identification mechanism: labels are hung at both ends of the cable and in the middle of the protective pipe, wiring diagrams are set in the equipment box and DAU box, and the communication link follows a daisy-chain topology, with branching devices installed at the branch points.

10. The method for constructing a dam inverted hole and its supporting automated monitoring system according to claim 1, characterized in that: In the parameter correction algorithm, the short-term volatility coefficient and the long-term drift coefficient are determined as follows: the short-term volatility coefficient decreases exponentially with the increase of system runtime, and the decay rate is determined by the short-term decay time constant and the proportional coefficient; the long-term drift coefficient gradually tends to a stable value with the increase of system runtime, and the stabilization rate is determined by the long-term stabilization time constant and the proportional coefficient. The calibration of the instrument installation deflection angle is as follows: the deflection angle during instrument installation is determined by the difference between the angle of the line connecting two reference points in the engineering coordinate system and the angle of the line connecting these two points measured by the instrument. The standard deviation in the data fusion algorithm is calculated as follows: The standard deviation of automated measurement reflects the dispersion of multiple measurements by the automated system. It is obtained by taking the square root of the sum of squares of the deviations of each measurement from the average value, divided by the number of measurements. The standard deviation of manual measurement reflects the dispersion of multiple manual verification values. It is obtained by taking the square root of the sum of the squares of the deviations of each verification value from the average value and the number of verifications.

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