Prefabricated square block mounting method

Abstract

The invention relates to a prefabricated square block mounting method, belongs to the technical field of wharf building construction, and aims to solve the problems of insufficient flatness of a foundation bed, large alignment deviation of prefabricated square blocks and poor seam sealing performance in a traditional mounting method. A trapezoidal tenon is pre-embedded in the bottom surface of the prefabricated square block and is matched with a groove in the top surface, and accurate embedding of the tenon and the groove is realized by combining sectional descending speed control of a crane ship, total station and RTK positioning data fusion deviation correction and underwater camera alignment confirmation; and after installation, scanning is conducted through a depth sounding system, a secondary leveling program is started, the wharf structure installation precision and the overall stability are improved, and the later settlement risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wharf construction. More specifically, the present invention relates to a method for installing precast blocks. Background Art

[0002] In the field of wharf construction, the installation accuracy of precast blocks directly affects the overall stability and service life of the wharf structure. In traditional construction methods, the sand cushion layer on the bed surface is often leveled mechanically. However, due to the insufficient accuracy of the leveling equipment and the lack of real-time monitoring means, the flatness error of the sand cushion layer is likely to exceed the reasonable range. Especially in the underwater operation environment, the bed surface is affected by water flow scouring or sediment, and local depressions or bulges are likely to occur, resulting in uneven bottom support of the precast blocks after installation. This problem is more significant in sea areas with frequent tidal changes. Insufficient flatness of the sand cushion layer will directly cause the precast blocks to tilt or the joints to be misaligned.

[0003] The hoisting and alignment of precast blocks have long relied on manual visual adjustment or a single measuring device. For example, in some projects, only total stations are used for plane coordinate monitoring. However, during the hoisting process, due to factors such as the swaying of the crane ship and the interference of wind and waves, the update frequency of the measurement data is difficult to meet the dynamic deviation correction requirements. When the precast block is lowered to the underwater stage, due to the high turbidity of the water body, the traditional camera system cannot clearly capture the docking state of the positioning tenons and grooves, resulting in the operators having to rely on experience to judge the lowering timing, and the risk of alignment deviation increases significantly. In addition, the data of a single measuring device is easily interfered by the environment. For example, the measurement accuracy of the total station decreases in strong light or rainy and foggy weather, and the GPS positioning is prone to signal drift when approaching metal structures, further exacerbating the alignment error.

[0004] The deficiency of the joint treatment process is also a prominent defect of the traditional method. During conventional concrete filling, due to the inaccurate control of the vibration depth and frequency of the underwater vibration equipment, air bubbles or voids are easily formed inside the joint. These defects will accelerate the material deterioration under the action of tidal cycles, resulting in leakage or even structural cracking at the joint. More seriously, insufficient joint sealing will cause sediment intrusion, and the long-term accumulation will cause uneven distribution of the friction force between the blocks, thereby causing local settlement. In addition, there is a lack of effective density detection means after the joint is filled. It is often necessary to wait for the concrete to solidify and then verify by destructive sampling, which is not only inefficient but also may increase the repair cost.

[0005] The overall leveling process after installation also faces technical bottlenecks. The traditional method relies on manual use of a level to detect the elevation of each block one by one, with low detection efficiency and being easily affected by human errors. For a large area of block groups, it is difficult for manual detection to cover comprehensively, and some areas with excessive deviations may be missed. In addition, existing leveling means mostly use shim adjustment or local jacking. However, in the underwater environment, the shims are easily displaced by water flow scouring, and the jacking operation may cause chain offsets of adjacent blocks due to the lack of precise force control. More critically, the traditional method lacks a systematic deviation determination standard. For example, the quantization thresholds of the normal vector angle or elevation deviation are not clearly defined, resulting in a large degree of randomness in the leveling operation and making it difficult to ensure the overall flatness of the wharf.

[0006] The reasons for the above problems can be attributed to multiple aspects: Firstly, the underwater environment significantly restricts the performance of measurement equipment. For example, optical instruments are affected by the water body's light transmittance, and sonar equipment is easily interfered by background noise. Secondly, the dynamic characteristics of the hoisting process do not match the static analysis mode of measurement data, and existing rectification algorithms are difficult to achieve real-time response. Thirdly, the fusion technology of multi-source data (such as optical coordinates and satellite positioning data) is not yet mature. Problems such as coordinate system conversion errors and data timestamp asynchronization lead to lag or distortion of rectification instructions. These technical bottlenecks make it difficult to achieve high-precision and high-efficiency precast block installation. Especially in large-scale wharf projects, the cumulative error superposition effect will further amplify the structural risk. Summary of the Invention

[0007] An object of the present invention is to solve at least the above problems and provide at least the advantages described hereinafter.

[0008] To achieve these and other advantages in accordance with the present invention, there is provided a method for installing precast blocks, comprising the following steps: Lay a sand cushion layer on the surface of the wharf foundation bed. The sand cushion layer is made of medium-coarse sand, and the flatness error of the top surface of the sand cushion layer is controlled within a preset threshold range by a laser leveling device; Embed positioning tenons at the four corner positions of the bottom surface of the precast block. The cross-sectional shape of the positioning tenon is trapezoidal, the width of the top surface is smaller than that of the bottom surface, and the height is proportional to the bottom thickness of the precast block; Reserve positioning grooves at the four corner positions of the top surface of adjacent precast blocks, which match the shape of the positioning tenons. A rubber buffer layer is provided on the inner wall of the positioning groove; Use a crane ship equipped with a positioning system to hoist the precast block, install positioning marks on the four side surfaces of the precast block, and monitor the aerial attitude of the precast block in real time through a measuring instrument; Input the installation coordinates of the precast block into the control terminal of the crane ship, and guide the crane ship to hover above the target installation position through the positioning system; Operate the fine-tuning device of the crane ship to lower the precast block at a segmented descent speed, and at the same time adjust the horizontal inclination angle of the precast block according to the feedback data of the measuring instrument to align the central axis of the positioning tenon with the central axis of the positioning groove; When the positioning tenon contacts the entrance of the positioning groove, pause the lowering action and use an underwater camera system to confirm the alignment situation; continue to complete the final installation at the reduced descent speed so that the positioning tenon is completely embedded in the positioning groove, and the vertical joint width between adjacent precast blocks is controlled within the preset dimension range; Fill the joint with epoxy resin concrete and use an underwater vibrator to vibrate it in layers until it is dense; After the installation is completed, scan the overall plane position of the installed block group through the bathymetric system, and start the secondary leveling procedure for a single block that exceeds the plane deviation threshold.

[0009] Preferably, the positioning mark includes four groups of prism groups. Two groups of prism groups are respectively installed at the centers of two surfaces on the landward side of the precast block, and the other two groups of prism groups are installed at the centers of two surfaces on the seaward side of the precast block; The measuring instrument includes two total stations. The first total station is set up on the observation pier on the landward side of the wharf bed, and the second total station is set up on the floating platform on the seaward side of the wharf bed. The first total station alternately scans the prism groups on two surfaces of the precast block on the landward side through the automatic target recognition function, and the second total station synchronously scans the prism groups on two surfaces facing the water; an optical measurement link is established between the total station and the prism group through the laser reflection signal to obtain the three-dimensional coordinate data of each prism group in real time.

[0010] Preferably, the positioning mark also includes an RTK positioning module, which is set at the center of the top surface of the precast block and is data-connected to the total station. The RTK positioning module real-time feeds back the horizontal position and elevation of the center point of the top surface of the precast block, and the crane ship control terminal compares the prism group coordinate data with the RTK positioning data to generate a three-dimensional deviation correction instruction for the crane ship hook.

[0011] Preferably, when the crane ship control terminal compares the prism group coordinate data with the RTK positioning data, it generates a three-dimensional deviation correction instruction according to the following steps: 1) Establish a unified coordinate system for the construction area and convert the prism group coordinate data measured by the total station to the WGS-84 coordinate system used by the RTK positioning data; 2) Calculate the three-dimensional deviation vector ΔP = P1 - P0 of the center point coordinates P1 of the prism group and the center point coordinates P0 of the RTK positioning module; 3) Set the deviation threshold: in the horizontal direction ΔP xy ≤ 50 mm, in the elevation direction ΔP z ≤ 30 mm; 4) When |ΔP xy| > 50 mm or | ΔP z When | > 30 mm, start the data fusion algorithm to calculate the fusion coordinate P, P = α × P1 + β × P0, where the weight α = 0.7 is assigned to the coordinate data of the prism group, and the weight β = 0.3 is assigned to the RTK positioning data; 5) According to the difference Δ = Q - P between the fusion coordinate P and the designed installation coordinate Q, decompose it into the front - rear deviation Δx, left - right deviation Δy, and lifting deviation Δz in the moving direction of the crane vessel; 6) Convert Δx and Δy into the lateral and longitudinal thrust values F of the crane vessel's thrusters x = K x × Δx, F y = K y × Δy, where K x = 300 N / mm, K y = 500 N / mm; 7) Convert Δz into the hook lifting speed command V z = 1.2 × Δz (when Δz > 0) or V z = 0.8 × Δz (when Δz < 0), in the unit of mm / s; 8) Update the deviation correction command every 0.5 seconds until the hook position is locked when Δx ≤ 10 mm, Δy ≤ 10 mm, and Δz ≤ 5 mm.

[0012] Preferably, the segmented descent speed includes three - stage control processes: 1) The descent speed in the first stage is set to V1 = 8 cm / s and continues until the bottom end of the positioning tenon is H1 = 80 cm above the entrance of the positioning groove; 2) The descent speed in the second stage is reduced to V2 = 3 cm / s, and at the same time, start the RTK - prism data fusion control program: a. Obtain the real - time planar coordinates (x i , y i ) of the four positioning tenons through the total station, i = 1~4; b. Obtain the center point coordinates (x0, y0, z0) of the top surface of the precast block through the RTK positioning module; c. Calculate the centroid coordinates (x c , y c ) = (Σx i / 4, Σy i / 4); d. When |x c - x0| > 20 mm or |y c - y0| > 20 mm, generate the cylinder compensation amount: ΔX = 0.7×(x c - x0)+0.3×(x 0设计值 - x0); ΔY = 0.7×(yc - y0) + 0.3×(y 0设计值 - y0); 3) In the third stage, the descending speed is reduced to V3 = 1 cm / s. When the bottom end of the positioning tenon is 20 cm above the entrance of the positioning groove: a. Switch to the prism coordinate dominant mode and calculate the plane fitting normal vector n = (a, b, c) of the coordinates of the four tenons; b. According to the angle θ = arccos(n·n0 / |n||n0|) between the normal vector n and the designed plane normal vector n0, when θ > 0.5°: i. Calculate the horizontal inclination compensation amounts ΔX = 15×a, ΔY = 15×b (unit: mm / °); ii. Control the hydraulic cylinder to perform the ΔX and ΔY compensations at a speed of 4 mm / s; c. Continuously monitor θ until θ ≤ 0.2°, lock the cylinder and complete the final lowering.

[0013] Preferably, the secondary leveling procedure is implemented according to the following steps: 1) Conduct strip scanning along the dock axis direction through a multibeam sounding system to generate three-dimensional point cloud data of the installed block group, and set the point cloud density to no less than 400 measurement points per square meter; 2) Import the three-dimensional point cloud data into the point cloud processing module and perform the following operations: a. Extract the point cloud subset of the top surface of each precast block, and use the random sample consensus algorithm to fit the top surface plane equation Ax + By + Cz + D = 0, where A is the component of the plane normal vector in the x-axis direction, B is the component of the plane normal vector in the y-axis direction, C is the component of the plane normal vector in the z-axis direction, D is the signed distance from the plane to the origin, unit: meter, x is the coordinate along the dock axis, y is the coordinate perpendicular to the dock axis, and z is the elevation; b. Calculate the angle θ = arccos(|A·A0 + B·B0 + C·C0| / (√(A² + B² + C²) × √(A0² + B0² + C0²))) between the normal vectors of each top surface plane equation and the designed plane equation; c. Mark the single block with θ > 0.5° or the plane elevation deviation |Δz| > 30 mm as the leveling object; 3) Start underwater robot-assisted leveling for the marked blocks: a. The underwater robot carries a hydraulic leveling jack to abut against the bottom surface of the target block on the water-facing side, and the base of the jack is adsorbed on the top surface of the stabilized block; b. Synchronously lift the four jacks to the pressure value F = 1.2×(self-weight of the target block × sinθ), and the lifting height h = Δz + 5 mm; c. Under the state of maintaining the jacking, inject hydraulic epoxy resin mortar into the gap at the bottom surface of the target block, and keep the grouting pressure stable at 0.3 MPa for 120 seconds; 4) Use an inserted underwater vibrator to perform three times of vibration along the radial direction of the grouting hole, with each vibration lasting for 15 seconds, and the distance between adjacent vibration points not being greater than 300 mm; 5) 24 hours after the vibration is completed, re - execute steps 1) - 2) to verify the leveling effect until θ ≤ 0.3° and |Δz| ≤ 10 mm.

[0014] The present invention has at least the following beneficial effects: The present invention adopts the combined design of the flatness of the sand cushion layer and the tenon - groove to reduce the installation deviation, so that the error of the vertical joint width ≤ 5 mm. The three - dimensional dynamic deviation correction is realized by the data fusion control of the total station and RTK, so that the plane positioning error ≤ 10 mm. The combination of epoxy resin filling and secondary leveling procedure ensures the joint sealing and the overall structural stability.

[0015] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. Specific embodiments

[0016] The following further elaborates on the present invention in conjunction with embodiments, so that those skilled in the art can implement it according to the text of the specification.

[0017] The present invention provides a method for installing precast blocks, including the following steps: Lay a sand cushion layer on the surface of the wharf bed. The sand cushion layer is made of medium - coarse sand, and the flatness error of the top surface of the sand cushion layer is controlled within a preset threshold range by a laser leveling device; Embed positioning tenons at the four - corner positions of the bottom surface of the precast block. The cross - sectional shape of the positioning tenon is trapezoidal, the top surface width is smaller than the bottom surface width, and the height is proportional to the bottom thickness of the precast block; Reserve positioning grooves at the four - corner positions of the top surface of adjacent precast blocks, which match the shape of the positioning tenons. A rubber buffer layer is provided on the inner wall of the positioning grooves; Use a crane ship equipped with a positioning system to hoist the precast block, install positioning marks on the four - side surfaces of the precast block, and monitor the aerial attitude of the precast block in real time through a measuring instrument; Input the installation coordinates of the precast block into the control terminal of the crane ship, and guide the crane ship to hover above the target installation position through the positioning system; Operate the fine - tuning device of the crane ship to lower the precast block at a segmented descent speed, and at the same time adjust the horizontal inclination angle of the precast block according to the feedback data of the measuring instrument, so that the central axis of the positioning tenon is aligned with the central axis of the positioning groove; When the positioning tenon contacts the entrance of the positioning groove, suspend the lowering operation and use an underwater camera system to confirm the alignment; continue to complete the final installation at the reduced lowering speed so that the positioning tenon is fully embedded in the positioning groove, and the vertical joint width between adjacent precast blocks is controlled within the preset dimension range; Fill the joint with epoxy resin concrete and use an underwater vibrator to vibrate it in layers until it is dense; After the installation is completed, use a sounding system to scan the overall planar position of the installed block group, and initiate a secondary leveling procedure for individual blocks that exceed the planar deviation threshold.

[0018] Specifically, medium-coarse sand with a particle size of 0.3 - 2.36 mm can be selected for laying the sand cushion, and the flatness error threshold is set at ±10 mm. The laser leveling equipment can be the Trimble® GCS900 system, and the sand material source is a local sand and gravel plant. The positioning tenon of the precast block is designed with a trapezoidal cross-section, the top width is 70% - 80% of the bottom width, and the height is 1 / 3 - 1 / 2 of the bottom thickness of the precast block. The groove depth is 5 - 10 mm larger than the tenon height, and the thickness of the rubber buffer layer set on the inner wall of the groove is 3 - 5 mm, and neoprene material can be selected.

[0019] The sand cushion is laid on the surface of the wharf foundation bed with a laying thickness of 200 - 300 mm. The positioning tenons are embedded at the four corners of the bottom surface of the precast block, 100 - 150 mm away from the edge. The positioning grooves are located at the four corners of the top surface of adjacent blocks, corresponding to the positions of the tenons. During construction, after the foundation bed is excavated and leveled, the sand cushion is laid, and the laser leveling equipment controls the planar error through real-time scanning. When producing the precast block, trapezoidal tenons are cast at the four corners of the bottom surface, and a neoprene layer is embedded in the top groove, and the installation deviation is reduced through the guidance of the trapezoidal cross-section.

[0020] The crane ship can be the ZPMC model of Zhenhua Heavy Industries, equipped with a GPS-RTK positioning system (such as the Trimble® R12 module). The positioning marks can be the Leica® circular prism group, installed at the center of the four side surfaces of the precast block, 200 mm away from the top edge. The total station can be the Trimble® S9 model, one is installed on the observation pier on the land side of the wharf, and the other is placed on the floating platform on the water side. The RTK module is fixed at the center of the top surface of the precast block and establishes a data connection with the total station.

[0021] The segmented descent speed is divided into three stages: the first stage is 8 cm / s, which lasts until the bottom of the tenon is 80 cm away from the entrance of the groove; the second stage is reduced to 3 cm / s, and the data fusion control program is started; the third stage is reduced to 1 cm / s, and the prism coordinate dominant mode is switched. The horizontal inclination adjustment threshold is plane deviation ≤50 mm, elevation deviation ≤30 mm, and the correction instruction update frequency is 0.5 seconds / time. The total station obtains coordinates by scanning the prism group, and the RTK module feeds back the top surface center position. The control terminal generates thruster thrust and hook speed instructions after fusing the data to achieve three-dimensional dynamic correction.

[0022] Epoxy resin concrete can use Sika® underwater epoxy mortar, with a slump of 120-150 mm and an initial setting time of ≤45 minutes. The vibrator insertion spacing is ≤300 mm, and the single vibration time is 15 seconds. The multi-beam depth sounding system can use Teledyne RESON® SeaBat T50, and the point cloud density is set to 400 measurement points per square meter. The leveling jack can use Schilling® hydraulic type, with a pressure value of 1.2 times the weight of the target block, and the grouting pressure is stable at 0.3 MPa.

[0023] Before filling the joints, remove debris and inject epoxy resin concrete in layers, with each layer thickness ≤200 mm. After installation, the multi-beam system scans to generate a three-dimensional point cloud, screening blocks with a normal vector angle >0.5° or an elevation deviation >30 mm. The underwater robot carries a jack and adsorbs it on the top surface of the stable block, lifting the water side of the target block to a height of Δz+5 mm. After grouting, vibrate three times, with the distance between adjacent vibration points ≤300 mm. Retest after 24 hours until the normal vector angle is ≤0.3° and the elevation deviation is ≤10 mm.

[0024] In the above embodiment, the flatness of the sand cushion layer and the tenon-groove design reduce the installation deviation, so that the vertical joint width error is ≤5 mm. The total station and RTK data fusion control realize three-dimensional dynamic correction, so that the plane positioning error is ≤10 mm. The epoxy resin filling is combined with the secondary leveling procedure to ensure the sealing of the joint and the overall stability of the structure.

[0025] In another embodiment, the positioning mark comprises four groups of prism groups, two groups of prism groups are respectively installed at the centers of two surfaces on the land side of the prefabricated block, and the other two groups of prism groups are installed at the centers of two surfaces on the sea side of the prefabricated block; The measurement instrument includes two total stations. The first total station is set up on the onshore observation pier of the wharf bed, and the second total station is set up on the floating platform on the water side of the wharf bed. The first total station alternately scans the prism groups on the two surfaces of the precast block facing the land side through the automatic target recognition function, and the second total station synchronously scans the prism groups on the two surfaces facing the water side; an optical measurement link is established between the total station and the prism groups through laser reflection signals to obtain the three-dimensional coordinate data of each prism group in real time.

[0026] Specifically, four groups of circular prism groups can be selected as the positioning marks. Each group of prisms can be installed at the center position of the surfaces of the precast block facing the land side and the sea side, 200 millimeters away from the top edge. The prism group can be of the Leica® GPR121 model. The installation base of each group of prisms is made of 304 stainless steel and is fixed to the surface of the precast block through expansion bolts. The optical reflection surface of the prism group faces the direction of the wharf axis, and the wavelength range of the reflection signal is 532 - 650 nanometers. After installation, the total station is used to calibrate the coordinates of the prism group, and the calibration error threshold is set to ±1 millimeter. During the construction process, the surface of the prism group needs to be cleaned regularly to avoid the influence of seawater salt spray or sediment on the reflection signal intensity.

[0027] The total station can be of the Trimble® S9 model. The first total station is set up on the onshore observation pier of the wharf bed. The height of the observation pier is 1.5 meters and it is cast with C30 concrete. The second total station is set up on the floating platform on the water side. The platform is fixed by anchor chains, and the horizontal sway amplitude threshold ≤ 5 millimeters. The automatic target recognition frequency of the total station is set to 10 Hz, and the scanning angle covers a range of ±45°.

[0028] When establishing the optical measurement link, the total station emits a laser beam with a wavelength of 650 nanometers, and the reflection signal intensity threshold of the prism group is set to ≥80%. The onshore total station alternately scans the prism groups on the front and rear surfaces facing the land side, and the water-side total station synchronously scans the left and right prism groups facing the sea side. The data sampling interval is 0.1 second. The measurement data is transmitted to the control terminal of the crane ship through optical fiber, and the transmission delay ≤ 10 milliseconds. If the signals of the two prism groups are lost during a single scan, the system automatically switches to the redundant prism group data, and the redundant switching time ≤ 0.5 second.

[0029] The three-dimensional coordinate data of the prism group obtained by the total station in real time is used to calculate the coordinates of the center point of the precast block by least squares fitting. The coordinate system conversion adopts the WGS-84 ellipsoid model, and the elevation reference plane is the average sea level of the construction area. When fusing data, the weight distribution of the measurement values of the onshore and water-side total stations is 6:4, and the plane coordinate weighted average error threshold is set to ±3 millimeters.

[0030] During the construction process, if the prism group is temporarily blocked (such as when a ship passes by), the system automatically enables the historical trajectory prediction mode, and the prediction duration ≤ 5 seconds. After each hoisting operation is completed, the total station executes a self-check program to detect the power attenuation value of the laser transmitter. If the attenuation ≥ 15%, a maintenance alarm is triggered. During maintenance, the filter of the total station or the reflection film of the prism group can be replaced. After replacement, the calibration process needs to be executed again.

[0031] In the above embodiments, the prism groups are symmetrically arranged and the total station performs dual-station collaborative measurement to achieve real-time three-dimensional monitoring of the in-air attitude of the precast blocks, so that the plane positioning error ≤ 5 mm. The redundant design of the optical measurement link combined with the data fusion algorithm ensures the measurement continuity in harsh environments. The self-check and maintenance mechanism of the total station extends the service life of the equipment and reduces the risk of construction interruption.

[0032] In another embodiment, the positioning mark further includes an RTK positioning module, which is arranged at the center of the top surface of the precast block and establishes a data connection with the total station. The RTK positioning module real-time feeds back the horizontal position and elevation of the center point of the top surface of the precast block. The lifting ship control terminal compares the coordinate data of the prism group with the RTK positioning data to generate a three-dimensional deviation correction instruction for the lifting hook of the lifting ship.

[0033] Specifically, the RTK positioning module can select the Trimble® R12 model, which is installed at the center position of the top surface of the precast block and fixed by a stainless steel base with a thickness of 5 mm. The plane positioning accuracy threshold of the RTK module is ±10 mm, and the elevation positioning accuracy threshold is ±15 mm. The total station can select the Trimble® S9 model, which establishes a data link with the RTK module through a wireless data transmission radio, and the data transmission delay threshold is set to ≤ 50 milliseconds.

[0034] The installation position of the RTK module is at a distance of 1 / 4 - 1 / 3 of the side length of the precast block from the edge of the top surface. For example, for a block with a side length of 5 meters, the installation point is 1.25 - 1.67 meters from the edge. When the total station is set up on the observation pier on the land side of the wharf, the height of the observation pier is 1.2 - 1.8 meters and is cast with C30 concrete. Before construction, the RTK module needs to be calibrated with the base station, and the calibration error threshold is set to ±3 mm in the horizontal direction and ±5 mm in the elevation direction.

[0035] During the working process, the RTK module real-time collects the coordinates of the center point of the top surface of the precast block in the WGS-84 coordinate system and transmits them to the lifting ship control terminal through the data link. The total station synchronously measures the coordinates of the prism group, and the control terminal compares the two types of data after converting them to a unified coordinate system to ensure that the synchronization error of the data time stamps ≤ 0.1 second.

[0036] When the lifting ship control terminal performs the comparison between the coordinate data of the prism group and the RTK positioning data, the three-dimensional deviation correction instruction is generated according to the following steps: 1) Establish a unified coordinate system for the construction area, and convert the coordinate data of the prism group measured by the total station to the WGS-84 coordinate system used by the RTK positioning data. The coordinate system conversion adopts the seven-parameter method, and the parameters are calibrated by 3 known control points within the construction area, and the distance between the control points is 200 - 500 meters; 2) Calculate the three-dimensional deviation vector ΔP = P1 - P0 of the center point coordinate P1 of the prism group and the center point coordinate P0 of the RTK positioning module; 3) Set the deviation threshold: in the horizontal direction, ΔP xy ≤50 mm, and in the elevation direction, ΔP z ≤30 mm; 4) When |ΔP xy | > 50 mm or |ΔP z | > 30 mm, start the data fusion algorithm, and calculate the fusion coordinate P, P = α×P1 + β×P0, where the weight α = 0.7 is assigned to the coordinate data of the prism group, and the weight β = 0.3 is assigned to the RTK positioning data; 5) According to the difference Δ = Q - P between the fusion coordinate P and the designed installation coordinate Q, decompose it into the front-back deviation Δx, left-right deviation Δy, and lifting deviation Δz in the moving direction of the crane ship; 6) Convert Δx and Δy into the lateral and longitudinal thrust values F x = K x ×Δx, F y = K y ×Δy, where K x = 300 N / mm, K y = 500 N / mm. The thrust actuator can select the Bosch® electro-hydraulic proportional valve, with a response time ≤ 0.3 seconds and a pressure fluctuation threshold ≤ 5%.; 7) Convert Δz into the hook lifting speed command V z = 1.2×Δz (when Δz > 0) or V z = 0.8×Δz (when Δz < 0), with the unit of mm / s; 8) Update the deviation correction command every 0.5 seconds until the hook position is locked when Δx ≤ 10 mm, Δy ≤ 10 mm, and Δz ≤ 5 mm.

[0037] If the data link is interrupted during the deviation correction process, the system automatically switches to the single data source mode of the prism group to maintain the minimum deviation correction function.

[0038] The hoisting vessel's thruster can select the Schottel® SRP300 full-rotation thruster. The maximum thrust of a single unit is 300 kN, and the lateral-to-longitudinal thrust distribution ratio is 1:1.67. The hook lifting mechanism can select the Terex® DCV300 winch, and the speed control accuracy is ±1 mm / s. The compensation speed of the hydraulic cylinder is set to 4 mm / s. The calculation formulas for the compensation amounts ΔX and ΔY are ΔX = 15×a and ΔY = 15×b (where a and b are the components of the normal vector).

[0039] The thruster thrust command is transmitted to the vessel-mounted controller via the CAN bus, and the command parsing delay ≤ 20 ms. The winch speed command is closed-loop regulated through a PID controller, with the proportional coefficient K p = 2.5 and the integral time T i = 0.8 s. During the deviation correction process, if the hook speed fluctuation exceeds ±5% of the set value, the system automatically switches to the standby hydraulic power unit, and the switching time ≤ 0.5 s.

[0040] During operation, the deviation correction command preferentially corrects the horizontal deviation. After Δx and Δy meet the standards, the elevation deviation is adjusted. After each deviation correction is completed, the system records the deviation convergence curve. If the deviation does not decrease after three consecutive deviation corrections, an artificial intervention alarm is triggered. Maintenance personnel can manually input the compensation amount through the control terminal, and the thrust coefficient in the manual mode is reduced to 70% of the automatic mode.

[0041] In the above embodiments, the data fusion of the RTK module and the total station improves the positioning accuracy, and the convergence speed of the horizontal and elevation deviations is increased. The combination of the weight distribution and the dynamic deviation correction algorithm reduces the risk of positioning instability under extreme working conditions. The redundant control strategy ensures the continuity of the deviation correction process and reduces the probability of construction interruption In another embodiment, the segmented descent speed includes three-stage control processes: 1) The descent speed in the first stage is set to V1 = 8 cm / s and continues until the bottom of the positioning tenon is 80 cm above the entrance of the positioning groove; When the height difference reaches 80 cm, the second-stage control program is automatically triggered. If the height fluctuates by more than ±5 cm due to wind and waves, the system pauses the descent and activates the lateral compensation of the hydraulic cylinder.

[0042] During operation, the winch lowers the precast block at a constant speed, and the total station continuously feeds back the coordinates of the bottom of the tenon. The control terminal calculates the height deviation in real time. When the deviation exceeds the threshold, the hoisting attitude is adjusted through the lateral thrust of the thruster.

[0043] 2) The descent speed in the second stage is reduced to V2 = 3 cm / s, and at the same time, the RTK-prism data fusion control program is activated: a. Obtain the real-time planar coordinates (x of the four positioning tenons through the total station i, y i ), i = 1~4; b. Obtain the coordinates (x0, y0, z0) of the center point on the top surface of the precast block through the RTK positioning module; c. Calculate the centroid coordinates (x c , y c ) = (Σx i / 4, Σy i / 4); d. When |x c - x0| > 20 mm or |y c - y0| > 20 mm, generate the cylinder compensation amount: ΔX = 0.7×(x c - x0) + 0.3×(x 0设计值 - x0); ΔY = 0.7×(y c - y0) + 0.3×(y 0设计值 - y0); During construction, the control terminal updates the compensation instruction every 0.5 seconds. If the deviation does not decrease after three consecutive compensations, the system triggers an alarm and switches to the manual intervention mode. The data link uses optical fiber transmission, with a delay ≤ 10 milliseconds. When the signal is lost, the redundant prism group data is automatically enabled, and the redundant switching time ≤ 0.5 seconds.

[0044] 3) In the third stage, the descending speed drops to V3 = 1 cm / s. When the bottom end of the positioning tenon is H2 = 20 cm above the entrance of the positioning groove: a. Switch to the prism coordinate dominant mode and calculate the plane fitting normal vector n = (a, b, c) of the four tenon coordinates; b. According to the angle θ = arccos(n·n0 / |n||n0|) between the normal vector n and the designed plane normal vector n0, when θ > 0.5°: i. Calculate the horizontal inclination compensation amounts ΔX = 15×a, ΔY = 15×b (unit: mm / °); ii. Control the hydraulic cylinder to perform the ΔX and ΔY compensations at a speed of 4 mm / s; c. Continuously monitor θ until θ ≤ 0.2°, lock the cylinder, and complete the final lowering.

[0045] During the working process, the angle θ between the normal vectors is continuously monitored. If it exceeds the limit, compensation is triggered. After the compensation is completed, the lifting hook completes the final lowering at a speed of 1 cm / s, and the seam width error is controlled within ±5 mm. During maintenance, the hydraulic cylinder seal ring can be replaced or the prism reflecting surface can be cleaned. After replacement, the coordinates need to be recalibrated.

[0046] In the above embodiments, the segmented speed control is combined with the data fusion algorithm, reducing the dynamic deviation during the hoisting process, and the plane positioning error ≤ 10 mm. The prism dominant mode improves the end alignment accuracy, making the angle between the normal vectors converge within 0.2°.

[0047] In another embodiment, the secondary leveling program is implemented according to the following steps: 1) Perform strip scanning along the dock axis direction through a multibeam sounding system to generate three-dimensional point cloud data of the installed block group, and the point cloud density is set to no less than 400 measurement points per square meter; 2) Import the three-dimensional point cloud data into the point cloud processing module and perform the following operations: a. Extract the top surface point cloud subset of each precast block, and use the random sample consensus algorithm to fit the top surface plane equation Ax + By + Cz + D = 0, where A is the component of the plane normal vector in the x-axis direction, B is the component of the plane normal vector in the y-axis direction, C is the component of the plane normal vector in the z-axis direction, D is the signed distance from the plane to the origin, unit: meter, x is the coordinate along the dock axis, y is the coordinate perpendicular to the dock axis, and z is the elevation; b. Calculate the included angle θ between the normal vectors of each top surface plane equation and the designed plane equation: θ = arccos(|A·A0 + B·B0 + C·C0| / (√(A² + B² + C²) × √(A0² + B0² + C0²))); c. Mark the single block with θ > 0.5° or the plane elevation deviation |Δz| > 30 mm as the leveling object; 3) Start underwater robot-assisted leveling for the marked blocks: a. The underwater robot carries a hydraulic leveling jack and abuts against the bottom surface of the target block on the water-facing side, and the base of the jack is adsorbed on the top surface of the stabilized block; b. Synchronously lift the four jacks to the pressure value F = 1.2 × (self-weight of the target block × sinθ), and the lifting height h = Δz + 5 mm; c. Under the maintained lifting state, inject hydraulic epoxy resin mortar into the gap at the bottom of the target block, and the grouting pressure is stabilized at 0.3 MPa for 120 seconds; 4) Use an inserted underwater vibrator to perform three times of vibration along the radial direction of the grouting hole, with each vibration time of 15 seconds and the distance between adjacent vibration points not greater than 300 mm; 5) 24 hours after the vibration is completed, re-execute steps 1) - 2) to verify the leveling effect until θ ≤ 0.3° and |Δz| ≤ 10 mm.

[0048] Specifically, the multibeam sounding system can select the Teledyne RESON® SeaBat T50 model, and the point cloud density is set to no less than 400 measurement points per square meter. The threshold value θ of the plane normal vector included angle is set to > 0.5°, and the threshold value Δz of the elevation deviation is set to > 30 mm. The point cloud processing module can select the CloudCompare open-source software, the iteration times of the random sample consensus algorithm are set to 500 times, and the inlier distance threshold is set to 0.05 meter.

[0049] The multi-beam bathymetric system is installed on the survey vessel, and performs strip scanning at a speed of 5 knots along the axis of the wharf, with the scanning width covering the entire prefabricated block area. The point cloud data is transmitted to the shore-based control center via optical fiber, with a transmission delay of ≤1 second. During construction, if the area missing in a single scan is >5%, the system automatically triggers the re-scanning program, and the re-scanning speed is increased to 7 knots.

[0050] During the working process, the system extracts a subset of the point cloud on the top surface of each block, fits the plane equation and calculates the normal vector angle θ. When marking blocks with θ>0.5° or Δz>30 mm, color coding is used to distinguish them. Red marks θ exceeding the standard, and yellow marks Δz exceeding the standard. The data storage format is LAS 1.4, and the processing time of a single block data is ≤3 seconds.

[0051] The underwater robot can be a Schilling® Hydra model equipped with four hydraulic leveling jacks, with a maximum lifting force of 200 kN per jack. The jack base can be a magnetic adsorption plate with an adsorption force ≥ 1.5 times the weight of the target block. The grouting pipe can be a polyethylene hose with an inner diameter of 25 mm, and the grouting pressure is stabilized at 0.3 MPa for 120 seconds.

[0052] When the jack contacts the bottom surface of the target block facing the water, the center of the suction plate is 100-150 mm away from the edge of the block. The lifting height h=Δz+5 mm, where Δz is the measured value of the elevation deviation. The grouting holes are arranged at the four corners of the bottom surface of the target block, with a hole diameter of 50 mm and a hole depth of 200 mm. During construction, if the pressure fluctuation of a single jack is >10%, the system automatically switches to the backup hydraulic circuit.

[0053] During the operation, the underwater robot carries a jack and dives to the target location, and four jacks are lifted synchronously. The pressure value F=1.2×(target block weight×sinθ), where θ is the measured value of the normal vector angle. After the lifting is completed, epoxy resin mortar is pressed into the grouting hole, and the grouting rate is controlled to 5 liters / minute. The grouting volume is calculated based on the void volume, and 5% redundancy is reserved.

[0054] The inserted underwater vibrator can be Sika® BVC 650 model, with a vibrating rod diameter of 30 mm and a vibration frequency of 12,000 times / minute. The spacing between vibration points is ≤300 mm, the single vibration time is 15 seconds, and the overlapping area of adjacent vibration points is ≥50 mm. The retest verification time interval is 24 hours, the normal vector angle convergence threshold θ≤0.3°, and the elevation deviation convergence threshold Δz≤10 mm.

[0055] During the vibration operation, the vibrating rod is inserted radially along the grouting hole, and the insertion depth is 2 / 3 of the thickness of the grouting layer. Each hole is vibrated three times, with an interval of 2 minutes between each time. When the re-measured data is compared with the initial scanning data, the plane coordinate deviation threshold is set to ±5 mm, and the elevation deviation threshold is set to ±3 mm. If the re-measurement still exceeds the standard, the secondary leveling program is executed cyclically, and the maximum number of cycles is set to 3 times.

[0056] During the working process, after the vibration is completed, it is left to stand for 24 hours, during which the ambient water temperature changes are monitored. If the temperature difference is >5°C, the insulation cover covering program is triggered. The same multi-beam sounding system is used for re-measurement, and the scanning parameters are consistent with the initial measurement. After the data is verified, the system generates a leveling report, recording the initial deviation, leveling parameters and final convergence value.

[0057] In the above embodiment, the multi-beam depth sounding system is combined with the point cloud algorithm to accurately identify the leveling target, so that the normal vector angle detection error is ≤0.05°. The hydraulic jack is synchronously lifted and the grouting pressure is controlled to ensure uniform force during the leveling process, so that the single leveling elevation correction accuracy is ≤2 mm. The vibration parameters are combined with the re-measurement mechanism to improve the density of joint filling and reduce the risk of later structural settlement.

[0058] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A method for installing precast blocks, characterized in that, It includes the following steps: Lay a sand cushion layer on the surface of the wharf bedrock. The sand cushion layer is made of medium and coarse sand, and the flatness error of the top surface of the sand cushion layer is controlled within a preset threshold range by a laser leveling device; Embed positioning tenons at the four corners of the bottom surface of the precast block. The cross-sectional shape of the positioning tenon is trapezoidal, the width of the top surface is smaller than that of the bottom surface, and the height is proportional to the bottom thickness of the precast block; Reserve positioning grooves matching the shape of the positioning tenons at the four corners of the top surface of adjacent precast blocks, and a rubber buffer layer is provided on the inner wall of the positioning grooves; Use a crane ship equipped with a positioning system to hoist the precast block, install positioning marks on the four side surfaces of the precast block, and use a measuring instrument to monitor the aerial attitude of the precast block in real time; Input the installation coordinates of the precast block into the control terminal of the crane ship, and guide the crane ship to hover above the target installation position through the positioning system; Operate the fine-tuning device of the crane ship to lower the precast block at a segmented descending speed, and at the same time adjust the horizontal inclination angle of the precast block according to the feedback data of the measuring instrument, so that the central axis of the positioning tenon is aligned with the central axis of the positioning groove; When the positioning tenon touches the entrance of the positioning groove, pause the lowering operation, and use an underwater camera system to confirm the alignment situation; continue to complete the final installation at a reduced descending speed, so that the positioning tenon is completely embedded in the positioning groove, and the vertical joint width between adjacent precast blocks is controlled within a preset size range; Fill epoxy resin concrete in the joint, and use an underwater vibrator to vibrate it in layers until it is dense; After the installation is completed, scan the overall plane position of the installed block group through a sounding system, and start a secondary leveling program for a single block that exceeds the plane deviation threshold.

2. The precast block installation method according to claim 1, characterized in that, The positioning mark includes four groups of prism groups. Two groups of prism groups are respectively installed at the centers of the two surfaces of the precast block adjacent to the land side, and the other two groups of prism groups are installed at the centers of the two surfaces of the precast block adjacent to the sea side; The measuring instrument includes two total stations. The first total station is set up on the observation pier on the land side of the wharf bedrock, and the second total station is set up on the floating platform on the water side of the wharf bedrock. The first total station alternately scans the prism groups on the two surfaces of the precast block adjacent to the land side through the automatic target recognition function, and the second total station synchronously scans the prism groups on the two surfaces adjacent to the water side; an optical measurement link is established between the total station and the prism group through a laser reflection signal to obtain the three-dimensional coordinate data of each prism group in real time.

3. The precast block installation method according to claim 2, wherein, The positioning mark also includes an RTK positioning module, which is set at the center of the top surface of the precast block and is data-connected to the total station. The RTK positioning module real-time feeds back the horizontal position and elevation of the center point of the top surface of the precast block. The control terminal of the crane ship compares the prism group coordinate data with the RTK positioning data to generate a three-dimensional deviation correction instruction for the crane ship hook.

4. The precast block installation method according to claim 3, characterized in that, When the control terminal of the crane ship executes the comparison of the prism group coordinate data and the RTK positioning data, the three-dimensional deviation correction instruction is generated according to the following steps: 1) Establish a unified coordinate system for the construction area, and convert the prism group coordinate data measured by the total station to the WGS-84 coordinate system used by the RTK positioning data; 2) Calculate the three-dimensional deviation vector ΔP = P1 - P0 of the center point coordinates P1 of the prism group and the center point coordinates P0 of the RTK positioning module; 3) Set the deviation threshold: ΔP in the horizontal direction xy ≤ 50 mm, and ΔP in the elevation direction z ≤ 30 mm; 4) When |ΔP xy | > 50 mm or |ΔP z | > 30 mm, start the data fusion algorithm to calculate the fusion coordinate P, P = α × P1 + β × P0, where the weight α = 0.7 is assigned to the coordinate data of the prism group, and the weight β = 0.3 is assigned to the RTK positioning data; 5) According to the difference Δ = Q - P between the fusion coordinate P and the designed installation coordinate Q, it is decomposed into the front - rear deviation Δx, left - right deviation Δy, and lifting deviation Δz in the moving direction of the crane vessel; 6) Convert Δx and Δy into the lateral and longitudinal thrust values F of the lifting vessel's thrusters x =K x ×Δx, F y =K y ×Δy, where K x =300 N / mm, K y =500 N / mm; 7) Convert Δz to the hook lifting speed command V z = 1.2×Δz (when Δz > 0) or V z = 0.8×Δz (when Δz < 0), unit: mm / s 8) Update the deviation correction instruction every 0.5 s until the hook position is locked when Δx ≤ 10 mm, Δy ≤ 10 mm, and Δz ≤ 5 mm.

5. The precast block installation method according to claim 3, characterized in that, The segmented descent speed includes three - stage control processes: 1) The descent speed in the first stage is set to V1 = 8 cm / s and continues until the bottom of the positioning tenon is H1 = 80 cm above the entrance of the positioning groove; 2) The descent speed in the second stage is reduced to V2 = 3 cm / s, and at the same time, start the RTK - prism data fusion control program: a. Obtain the real-time planar coordinates (x i , y i ) of the four positioning tenons, where i = 1 to 4; b. Obtain the center point coordinates (x0, y0, z0) of the top surface of the precast block through the RTK positioning module; c. Calculate the centroid coordinates (x c , y c ) = (Σx i / 4, Σy i / 4); d. When |x c - x0| > 20 mm or |y c - y0| > 20 mm, generate the cylinder compensation amount: ΔX = 0.7×(x c - x0) + 0.3×(x 0设计值 - x0); ΔY = 0.7×(y c - y0) + 0.3×(y 0设计值 - y0); 3) The descent speed in the third stage is reduced to V3 = 1 cm / s. When the bottom of the positioning tenon is H2 = 20 cm above the entrance of the positioning groove: a. Switch to the prism - coordinate dominant mode and calculate the plane fitting normal vector n=(a, b, c) of the four tenon coordinates; b. According to the angle θ = arccos(n·n0 / |n||n0|) between the normal vector n and the designed plane normal vector n0, when θ > 0.5°: i. Calculate the horizontal inclination compensation amounts ΔX = 15×a, ΔY = 15×b (unit: mm / °); ii. Control the hydraulic cylinder to execute the ΔX and ΔY compensations at a speed of 4 mm / s; c. Continuously monitor θ until θ ≤ 0.2°, lock the hydraulic cylinder, and complete the final lowering.

6. The precast block installation method according to claim 1, characterized in that The secondary leveling program is implemented according to the following steps: 1) Conduct strip - type scanning along the dock axis direction through the multi - beam sounding system to generate the three - dimensional point cloud data of the installed block group, and the point cloud density is set to no less than 400 measurement points per square meter; 2) Import the three - dimensional point cloud data into the point cloud processing module and perform the following operations: a. Extract the point cloud subset of the top surface of each precast block, and use the random sample consensus algorithm to fit the top surface plane equation Ax + By + Cz + D = 0, where A is the component of the plane normal vector in the x - axis direction, B is the component of the plane normal vector in the y - axis direction, C is the component of the plane normal vector in the z - axis direction, D is the signed distance from the plane to the origin, unit: meter, x is the coordinate along the dock axis, y is the coordinate perpendicular to the dock axis, and z is the elevation; b. Calculate the angle θ = arccos(|A·A0 + B·B0 + C·C0| / (√(A² + B² + C²)×√(A0² + B0² + C0²))) between the normal vectors of each top surface plane equation and the designed plane equation; c. Mark the single block with θ > 0.5° or the plane elevation deviation |Δz| > 30 mm as the leveling object; 3) Start the underwater robot - assisted leveling for the marked blocks: a. The underwater robot carries a hydraulic leveling jack to abut against the bottom surface of the target block on the water - facing side, and the base of the jack is adsorbed on the top surface of the stabilized block; b. Synchronously lift the four jacks to the pressure value F = 1.2×(self - weight of the target block×sinθ), and the lifting height h = Δz + 5 mm; c. Under the state of maintaining the jacking, inject hydraulic epoxy resin mortar into the gap at the bottom surface of the target block, and the grouting pressure is stabilized at 0.3 MPa for 120 seconds; 4) Use an inserted underwater vibrator to perform three times of vibration along the radial direction of the grouting hole, with each vibration time of 15 seconds, and the distance between adjacent vibration points not greater than 300 mm; 5) 24 hours after the vibration is completed, re-execute steps 1)-2) to verify the leveling effect until θ≤0.3° and |Δz|≤10 mm.