Underwater drilling and blasting accurate positioning and depth control method

Abstract

The invention discloses a precise positioning and depth control method for underwater drilling blasting, relates to the technical field of underwater blasting, and aims to effectively control blast hole positioning deviation through data real-time linkage calibration, collect water level data through double-source cooperation of an automatic moisture indicator and a water level pressure sensor, eliminate interference and ensure data precision. An intelligent ultra-deep value decision-making model based on machine learning is constructed, historical engineering data and current actual measurement parameters are combined, an optimal ultra-deep value is automatically output, and in the trial explosion optimization stage, an optimal parameter combination is formed by monitoring the vibration speed and observing the explosion effect and optimizing the explosion parameters; a layered charging structure and a hole-by-hole delay detonating network are adopted, the maximum single-section detonating explosive amount is hierarchically controlled according to the distance of a protected object, vibration and shock wave data are continuously monitored in the blasting process, and parameters are adjusted immediately when the data exceed the standard; and the data is fed back to the intelligent model to complete iterative optimization, so that more accurate parameter support is provided for subsequent blasting.

Description

Technical Field

[0001] This invention relates to the field of underwater blasting technology, specifically a method for precise positioning and depth control in underwater drilling and blasting. Background Technology

[0002] Underwater drilling and blasting is a key construction technology in many fields such as waterway widening, reef blasting and dredging, and water conservancy construction. With the continuous growth of water transport demand and the increasing scale and complexity of water conservancy projects, more stringent requirements have been placed on the quality, efficiency, and safety of underwater drilling and blasting construction. Precise blasting positioning and depth control are the core elements to ensure that underwater blasting achieves the expected results, and are directly related to whether the project can proceed smoothly and the safety of the surrounding environment and personnel.

[0003] Existing underwater drilling and blasting technologies face numerous challenges. First, positioning relies heavily on single methods, such as GPS or total station positioning. This susceptibility to environmental interference makes accurate positioning difficult to guarantee, leading to frequent borehole deviations during actual construction, severely impacting blasting effectiveness and project quality. Second, water level data acquisition often uses single equipment, with interference from water flow and tides causing significant errors. Inaccurate water level data leads to substantial deviations in subsequent depth calculations, affecting drilling depth and blasting results. Third, the setting of over-depth values ​​lacks scientific basis, often relying on the experience of construction personnel, which is ill-suited to complex and variable geological and hydrological conditions, easily causing over- or under-excavation, increasing construction costs and time. Furthermore, the determination of blasting parameters lacks targeted trial blasting optimization, failing to fully consider the impact of different geological conditions and distances to protected objects, and lacks a comprehensive monitoring and dynamic correction mechanism. This results in frequent safety risks during blasting, such as excessive vibration and flying rocks, threatening surrounding buildings, the ecological environment, and the safety of construction personnel. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for precise positioning and depth control in underwater drilling and blasting. This method utilizes a combined positioning system of a total station and GPS, with real-time data linkage calibration to effectively control borehole positioning deviation. In the dynamic parameter calculation stage, it employs a dual-source collaborative acquisition of water level data using an automatic tide meter and a water level and pressure sensor to eliminate interference and ensure data accuracy. A machine learning-based intelligent ultra-deep value decision model is constructed, automatically outputting the optimal ultra-deep value by combining historical engineering data and current measured parameters. During the trial blasting optimization stage, blasting parameters are optimized by monitoring vibration velocity and observing blasting effects to form an optimal parameter combination suitable for the actual engineering situation. During precise blasting, explosive charges are processed according to the optimized parameters, employing a layered charging structure and a hole-by-hole delayed detonation network. The maximum single-stage detonation charge is controlled in stages according to the distance to the protected object to ensure safe and effective blasting. In the real-time monitoring and correction stage, vibration and shock wave data are continuously monitored during blasting, and parameters are adjusted immediately if the data exceeds the standard. After blasting, the effect is verified through professional testing methods, and the data is fed back to the intelligent model for iterative optimization, providing more accurate parameter support for subsequent blasting.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for precise positioning and depth control in underwater drilling and blasting, the method comprising the following specific steps: S1: Clarify the geological and hydrological conditions and design requirements of the blasting area, determine the core technical parameters, adopt a total station and GPS combined positioning system, adjust the position of the drill and blast vessel by using a winch, align the drilling rig with the preset blast hole coordinates, and control the positioning deviation within the preset range. S2: The measured water level in the blasting area is collected by a dual-source system of automatic tide meter and water level and pressure sensor. The optimal ultra-deep value is determined by intelligent ultra-deep value decision model. The actual drilling depth is calculated by combining the design bottom elevation. Drilling operation is carried out by down-the-hole drill rig with casing protection. S3: Test blasts are conducted in stages according to the incremental ratio of the designed charge amount. The vibration velocity of the mass points at the protected object is collected by the blasting vibration monitoring instrument. The blasting method is selected based on the monitoring results, and the hole spacing, row spacing, single-stage charge amount and detonation interval are optimized. S4: Process the explosive charge according to the optimized parameters and load it in layers. Set the number and position of the detonators that match the length of the explosive charge. Use a sequential delay detonation network connection. Control the maximum amount of explosive charge per segment according to the distance between the protected object and the blasting area. After the explosive charge is plugged, carry out the blasting. S5: During the blasting process, vibration and underwater shock wave data are monitored in real time using a blasting vibration monitor and hydrophone. If the data exceeds the safety threshold, the charge amount or detonation interval is adjusted immediately, and the blasting effect is verified after the blast.

[0006] Furthermore, in step S1, the geological and hydrological conditions of the blasting area, including lithology, reef thickness, and water depth, are clarified, and the core information of the design bottom elevation, minimum resistance line, and scope of the protected object are determined in conjunction with the engineering design documents.

[0007] Furthermore, in step S2, an intelligent ultra-deep value decision model based on the gradient boosting tree algorithm is constructed. The model uses data such as lithology hardness, rock weathering degree, water level change rate, and post-blasting effects from similar historical projects as training samples. The model parameters are iteratively optimized through the gradient boosting tree algorithm. The measured geological and hydrological parameters of the current project, including lithology, weathering degree, and water level change rate, are input into the model, and the model automatically outputs the optimal ultra-deep value that is suitable for the current working conditions.

[0008] Furthermore, the formula for the intelligent ultra-deep value decision model is: ,in, The optimal ultradepth value output by the model; These are the initial model predictions. The number of base learners, i.e., the number of decision trees; For the first Weight coefficients of each base learner; For the first Individual base learners, For the input feature vector, For the first The parameters of each base learner include the decision tree split nodes, leaf node output values, and input feature vectors. These correspond to lithological hardness, rock weathering degree, water level change rate, and blasting effect adaptation coefficient, respectively.

[0009] Furthermore, the input feature vector These correspond to lithological hardness, rock weathering degree, water level change rate, and blasting effect adaptation coefficient, respectively. The uniaxial compressive strength of rock is quantified. After being classified according to geological exploration standards, a quantitative value was assigned: 1.0 for strong weathering, 2.0 for moderate weathering, 3.0 for slight weathering, and 4.0 for unweathered weathering. Based on one hour of continuous monitoring data from dual-source water level acquisition equipment, the result was calculated by dividing the water level change by the monitoring time. The correction coefficient, derived from the reverse calculation of over-excavation and under-excavation amounts after historical engineering blasting, is calculated using the following formula: ,in This represents the actual depth of the historical engineering project. For historical engineering designs, the closer the coefficient is to 1.0, the better the blasting effect of the corresponding ultra-deep value.

[0010] Furthermore, in step S2, the actual borehole depth is calculated by combining the accurately measured water level, the designed bottom elevation, and the optimal ultra-deep value output by the intelligent model. The calculation formula is as follows: ,in It is the actual drilling depth. It is an accurate measured water level obtained through dual-source acquisition and collaborative verification. It is the engineering design baseline elevation. It is the optimal ultra-deep value output by the intelligent ultra-deep value decision model; select the drill bit of the corresponding diameter according to the drilling rig model, and before drilling, install the casing to press the ground protection hole opening, start the drilling rig to carry out drilling operations, and the drill rod impact and casing protection are carried out simultaneously during the drilling process.

[0011] Furthermore, in step S3, test explosions are conducted in stages according to the increasing proportion of the designed charge, that is, test explosions are conducted in stages according to 50%, 60%, 70%, and 80% of the designed charge, and 3-5 representative boreholes are selected for each test explosion.

[0012] Furthermore, in step S3, a blasting vibration monitoring instrument is used to collect the particle vibration velocity at the protected object. If the vibration velocity V > 0.5 cm / s, layered blasting is used; if V ≤ 0.5 cm / s, a single blast to the bottom is used.

[0013] Furthermore, in step S4, a layered charging structure is adopted. When the length of the explosive charge is <3m, one detonator is set at the bottom 1 / 3. When the length of the explosive charge is ≥3m, two detonators are set at the bottom 1 / 4 and 3 / 4 positions. After charging, the borehole is blocked with gravel water bags with a blocking length ≥0.5m.

[0014] Furthermore, in step S4, a hole-by-hole delayed detonation network is adopted, with a segment interval of 25ms within the hole and an interval of 50ms between holes, controlling the maximum single-segment detonation charge: ≤9kg when the distance to the protected object is 50-70m, ≤15kg when the distance is 70-80m, ≤23kg when the distance is 80-90m, and ≤32kg when the distance is above 90m.

[0015] Compared with existing technologies, this method for precise positioning and depth control in underwater drilling and blasting has the following advantages: This invention improves positioning accuracy by employing a combination of total station and GPS positioning and linkage calibration technology, solving the problem of insufficient accuracy of single positioning methods. It utilizes a dual-source collaborative acquisition and cross-verification of water level data from an automatic tide meter and a water level and pressure sensor to effectively reduce water level acquisition errors, providing a reliable foundation for depth calculation. A machine learning-based intelligent ultra-deep value decision model is constructed to achieve intelligent ultra-deep value decision-making and avoid biases from experience-based settings. Dynamically combining precise water level and intelligent ultra-deep values ​​makes depth control more accurate, improving construction efficiency and project quality. Through phased test blasting to optimize parameters and iterative model correction, parameter adaptability is enhanced, reducing construction risks. A full-process monitoring and dynamic correction mechanism is established to comprehensively control harmful effects such as vibration and shock waves, and to control the charge amount in each stage at different levels, maximizing the protection of the surrounding environment and personnel safety. Furthermore, parameters can be flexibly adjusted according to different engineering requirements, making it suitable for various underwater blasting projects such as channel blasting and water conservancy dredging, demonstrating significant engineering application value.

[0016] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart of a method for precise positioning and depth control in underwater drilling and blasting; Figure 2 A flowchart of step S2 in a method for precise positioning and depth control of underwater drilling and blasting; Figure 3 This is a flowchart of step S3 in a method for precise positioning and depth control of underwater drilling and blasting. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structure, features and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0020] This invention provides a method for precise positioning and depth control in underwater drilling and blasting. It employs a combined positioning system of a total station and GPS, with real-time data linkage calibration to effectively control borehole positioning deviation. In the dynamic parameter calculation stage, it utilizes a dual-source collaborative acquisition of water level data from an automatic tide meter and a water level and pressure sensor to eliminate interference and ensure data accuracy. A machine learning-based intelligent ultra-deep value decision model is constructed, automatically outputting the optimal ultra-deep value by combining historical engineering data and current measured parameters. During the trial blasting optimization stage, vibration velocity is monitored and blasting effects are observed to optimize blasting parameters, forming an optimal parameter combination suitable for the actual engineering situation. During precise blasting, explosive charges are processed according to the optimized parameters, employing a layered charging structure and a hole-by-hole delayed detonation network. The maximum single-stage detonation charge is controlled in stages according to the distance to the protected object to ensure safe and effective blasting. In the real-time monitoring and correction stage, vibration and shock wave data are continuously monitored during blasting, and parameters are adjusted immediately if the data exceeds the limits. After blasting, the effect is verified through professional testing methods, and the data is fed back to the intelligent model for iterative optimization, providing more accurate parameter support for subsequent blasting.

[0021] like Figure 1 As shown, S1: Clarify the geological and hydrological conditions and design requirements of the blasting area, determine the core technical parameters, adopt a total station and GPS combined positioning system, adjust the position of the drill and blast vessel by the winch, make the drill rig aligned with the preset blast hole coordinates, and control the positioning deviation within the preset range. Based on the geological survey results, the geological and hydrological conditions of the blasting area, such as lithology, reef thickness, and water depth, are determined; combined with the engineering design documents, the design bottom elevation, minimum resistance line, and scope of protection are determined.

[0022] The drilling and blasting vessel is driven to the pre-set anchorage range in the blasting area. Four sets of anchors are deployed for initial fixation. The total station and GPS combined positioning system is activated to collect the hull coordinates of the drilling and blasting vessel and the rotation center coordinates of the drilling rig in real time. These coordinates are compared with the pre-set blast hole coordinates to calculate the positioning deviation. The vessel position is gradually corrected by adjusting the length of the anchor winch until the deviation between the rotation center of the drilling rig and the pre-set blast hole coordinates is ≤3cm. After positioning is completed, the anchor winch is locked to prevent the vessel from shifting.

[0023] After positioning is completed, a dual-device cross-verification method is adopted. The total station is used to measure repeatedly three times, and the GPS positioning system continuously collects 10 sets of data. After confirming that the deviation is stable within the preset range, the next operation stage is started.

[0024] like Figure 2 As shown, S2: The measured water level in the blasting area is collected by a dual-source system of an automatic tide meter and a water level and pressure sensor. The optimal ultra-deep value is determined by an intelligent ultra-deep value decision model. The actual drilling depth is calculated by combining the design bottom elevation. Drilling operations are carried out by using a down-the-hole drill with casing protection. Three measuring points were evenly arranged in the center and surrounding area of ​​the blasting zone. Each measuring point was equipped with an automatic tide meter and a water level and pressure sensor to ensure the comprehensiveness of the collected data. Start the dual-source acquisition equipment and continuously collect water level data for 1 hour. After removing outliers, take the average of the two types of data for each group of measuring points to obtain the accurate water level value of each measuring point. Then calculate the average water level of the three measuring points as the final accurate measured water level. Collect data from over 50 sets of historical underwater blasting projects of similar nature. Each sample includes four input features and the corresponding actual depth value, as detailed below: Rock hardness The uniaxial compressive strength of the rock was tested using a pressure testing machine after on-site sampling. For example, if the uniaxial compressive strength of granite is 80 MPa, then... ; Rock weathering degree After being classified and quantified according to relevant regulations, strong weathering is assigned 1.0, moderate weathering 2.0, slight weathering 3.0, and unweathered 4.0. If the rock in the blasting area is moderately weathered sandstone, then... ; Rate of change of water level Based on one hour of monitoring data from a dual-source water level acquisition device, the change in water level is calculated as the ratio of the water level change to the monitoring time. For example, if the water level rises from 12.3m to 12.6m within one hour, then... ; Explosion effect compatibility coefficient According to the formula Calculation, where This represents the actual depth of the historical engineering project. For historical engineering design, the closer the coefficient is to 1.0, the better the blasting effect corresponding to that set of features. , ,but .

[0025] The specific steps for constructing an intelligent ultra-deep value decision model based on the gradient boosting tree algorithm are as follows: Number of base learners: Set to 100-500 decision trees. The number should be chosen to balance the model's fitting effect and generalization ability. Fewer than 100 trees may lead to underfitting and fail to fully learn the mapping relationship between features and deep values. More than 500 trees may lead to overfitting and reduce the model's adaptability to new projects. The optimal number was finally determined by 5-fold cross-validation.

[0026] Number of iterations: Consistent with the number of base learners, i.e., the number of iterations corresponding to the number of iterations, with one decision tree base learner trained in each iteration.

[0027] Learning rate: Set to 0.01-0.1 to control the weight contribution of each base learner. Too small a learning rate will increase the number of iterations and reduce training efficiency; too large a learning rate will easily cause the model to oscillate and not converge. Combined with cross-validation, the optimal range of 0.05-0.08 is selected to achieve a balance between training efficiency and model stability.

[0028] Maximum tree depth: Set to 3-8 layers. If the tree depth is too shallow (<3 layers), the base learner will not be able to fit properly. If the tree depth is too deep (>8 layers), the decision tree will overlearn the noise of the samples. Through verification, the optimal tree depth is determined to be 4-6 layers to ensure the generalization ability of the base learner.

[0029] Auxiliary parameters: Set the minimum number of sample splits to 10 (each node split contains at least 10 samples to avoid node overfitting) and the minimum number of leaf nodes to 5.

[0030] Algorithm iterative optimization process: Step 1: Initialize the model: Calculate the mean of the actual ultra-deep values ​​of all historical samples, and use this mean as the initial model prediction value to provide a basic benchmark for subsequent iterative training.

[0031] Step 2: Iteratively train the base learner: For each iteration: Calculate the residual: For each sample, subtract the predicted value of the model after the previous iteration from its actual over-depth value to obtain the prediction error of the current iteration, i.e., the residual. The residual reflects the part of the current model that has not yet been fitted.

[0032] Training the base learner: Using the calculated residual as the target output and the input feature vector of the sample as the input, train the decision tree base learner for the current round.

[0033] Split Node Selection: The splitting of each internal node in the decision tree is performed according to the "information gain ratio" criterion: First, the information entropy of the parent node is calculated, which reflects the dispersion of different ultra-deep value intervals in the parent node's samples; then, the weighted information entropy of all child nodes after splitting a certain feature is calculated, with the weighting based on the proportion of the number of samples in each child node to the total number of samples in the parent node; the information gain is obtained by subtracting the weighted information entropy of the child nodes from the information entropy of the parent node, which reflects the reduction in the dispersion of the samples after splitting; at the same time, the split information is calculated to measure the uniformity of the distribution of the child nodes after splitting; finally, the information gain ratio is obtained by dividing the information gain by the split information, and the feature with the largest information gain ratio and the corresponding split point are selected to complete the node splitting, ensuring that the split nodes have stronger discriminative ability.

[0034] Leaf node output value determination: The output value of each leaf node is the average of the actual ultra-depth values ​​of all samples contained in that node, ensuring that the output value can reflect the overall characteristics of the samples in that node.

[0035] Calculate the weight coefficients of the base learners: With the squared loss function as the objective, the weight coefficients of the current base learners are determined by minimizing the deviation between the model's predicted values ​​and the actual ultra-deep values, ensuring that the base learners play a reasonable contribution to the overall model.

[0036] Update the model: Multiply the prediction result of the current base learner by its weight coefficient, and then add it to the prediction result of the model after the previous iteration to obtain the updated model, so that the model gradually approximates the true ultra-deep value mapping relationship.

[0037] Step 3: Stop Iteration: When the number of iterations reaches the preset number of base learners, or when the residual sum of squares of the model decreases to less than 5% of the initial residual sum of squares, stop training. The model obtained at this time is the final intelligent ultra-deep value decision model.

[0038] Optimal ultra-deep value output: The measured input feature vector of the current project. (like Input the trained model, and use the formula Calculate and output the optimal ultradepth value. ,in, These are the initial model predictions. For the first The weight coefficients of each base learner For the first The predicted output of each base learner.

[0039] Based on the accurately measured water level, the designed bottom elevation, and the optimal over-depth value output by the intelligent model, the actual borehole depth is calculated according to the formula. Calculate the actual borehole depth. For example, , , ,but .

[0040] A down-the-hole drill rig with geological casing is selected to prevent borehole wall collapse during drilling. Before drilling, the casing is lowered to 1.0m below the borehole opening and secured with a hydraulic clamping device to ensure a tight seal between the casing and the borehole opening, preventing mud and sand from entering the borehole. The drill rig is started, and the drill rod impact frequency is set to 30Hz and the feed speed to 5cm / s. During drilling, the drill rod impact and casing advance synchronously, and the drilling resistance of the drill rod is monitored in real time. If the resistance changes abruptly, the feed speed is reduced to 2cm / s to prevent drill rod breakage. After drilling to the calculated depth, the machine is stopped and the drill is pulled up. The actual hole depth is measured using a measuring rope. If the deviation is ≤5cm, it is considered qualified. If the deviation exceeds the range, the drill is readjusted until the accuracy requirements are met.

[0041] like Figure 3As shown, S3: Test blasts are conducted in stages according to the incremental ratio of the designed charge amount. The vibration velocity of the mass points at the protected object is collected by the blasting vibration monitoring instrument. The blasting method is selected based on the monitoring results, and the hole spacing, row spacing, single-stage charge amount and detonation interval are optimized. Test detonations were conducted in four stages, with the explosive charge amount being 50%, 60%, 70%, and 80% of the design charge. 3-5 representative boreholes were selected for each stage. Assuming the design charge amount was set, the explosive charge amounts for each stage were 10kg, 12kg, 14kg, and 16kg, respectively.

[0042] Install blasting vibration monitoring instruments at key locations of the protected object (such as building foundations and pipeline interfaces). At least two instruments should be installed for each protected object. The monitoring instruments should be bonded to the surface of the protected object with epoxy resin to ensure the stability of data acquisition.

[0043] Test blasting operations were carried out in order from low charge to high charge. After each test blast, the vibration velocity V of the mass point at the protected object was recorded by the blasting vibration monitoring instrument, and the preliminary condition of rock fragmentation in the blasting area was observed.

[0044] If the detected particle vibration velocity V > 0.5 cm / s, it indicates excessive vibration, and layered blasting should be adopted (dividing the borehole into 2-3 layers, each layer 2-3 m high, with layered charges and detonation). If V ≤ 0.5 cm / s, a single blast should be used. For example, when testing with 14 kg of explosives, if V = 0.6 cm / s > 0.5 cm / s, the layered blasting method should be determined. Based on the vibration data and fragmentation effect of each stage of the test blast, the hole spacing, row spacing, single-stage charge amount, and detonation interval should be optimized. Hole spacing: The initial design hole spacing is 2.5m. If the rock fragments are too large (>0.8m) after the test blast, the hole spacing is reduced to 2.2m; if the fragmentation is excessive (fragment size <0.3m), the hole spacing is increased to 2.8m. Row spacing: determined as 0.8 times the optimized hole spacing. For example, if the optimized hole spacing is 2.2m, then the row spacing = 2.2 × 0.8 = 1.76m; Single-stage charge amount: If the vibration velocity is close to 0.5 cm / s, reduce the single-stage charge amount by 5%-10%; if the vibration velocity is low (<0.3 cm / s), the charge amount can be appropriately increased (not exceeding 80% of the design value). The initial design specifies a 25ms interval between segments within the holes and a 50ms interval between holes. If vibration superposition is detected, the interval between holes will be increased to 75ms to prevent shock wave superposition from causing excessive vibration.

[0045] S4: Process the explosive charge according to the optimized parameters and load it in layers. Set the number and position of the detonators that match the length of the explosive charge. Use a sequential delay detonation network connection. Control the maximum amount of explosive charge per segment according to the distance between the protected object and the blasting area. After the explosive charge is plugged, carry out the blasting. Process the explosive charge according to the optimized single-section charge (e.g., 12kg). The diameter of the explosive charge is 10mm smaller than the diameter of the borehole. The length is determined according to the layer height (e.g., if the layer height is 2.0m, the length of the explosive charge is 1.9m, with a 10cm gap reserved for installing the detonator). Detonator setup: When the length of the explosive charge is less than 3m, a detonator is installed at the bottom 1 / 3 of the charge to ensure complete detonation of the charge; When the length of the explosive charge is ≥3m, install one detonator at the bottom 1 / 4 and 3 / 4 positions of the charge to prevent incomplete detonation.

[0046] The explosive charges are filled in layers sequentially from the bottom of the hole upwards. After each layer of explosive charges is filled, a 10cm thick layer of crushed stone is laid to cushion the charge and prevent it from colliding and breaking. During the filling process, a special pushing tool is used to slowly send the explosive charges into the hole to avoid friction between the explosive charges and the hole wall, which could lead to explosive leakage.

[0047] After the explosive charge is loaded, the blockage is performed using gravel water bags. The gravel water bags are made of non-woven fabric, filled with 5-10mm gravel (70% filling rate) and filled with water. Each bag weighs 5kg and the blockage length is ≥0.5m. When blocking, the bags are compacted in layers, with 2 water bags in each layer. The bags are then compacted with a pusher until there are no gaps to prevent the explosive energy from leaking out of the orifice.

[0048] A sequential delay detonation network is adopted, and the detonating cord is connected in a segmented manner within the hole and in an inter-hole sequence. The detonators of different layers within the hole are connected in series by the detonating cord at intervals of 25ms. The detonation networks of adjacent holes are connected in parallel by the detonating cord at intervals of 50ms. After the connection is completed, the continuity of the network is checked to ensure that there are no open circuits or short circuits.

[0049] The maximum amount of explosive charge per stage is controlled according to the distance between the protected object and the blasting zone, with specific standards as follows: Distance 50-70m: Maximum single-stage detonation charge ≤9kg; Distance 70-80m: Maximum single-stage detonation charge ≤15kg; Distance 80-90m: Maximum single-stage detonation charge ≤23kg; For distances greater than 90m: the maximum single-stage detonation charge is ≤32kg. For example, if the protected object is 65m away from the blasting area, the maximum single-stage detonation charge should be controlled at 8kg to ensure that the vibration velocity does not exceed the safety threshold.

[0050] S5: During the blasting process, the vibration and underwater shock wave data are monitored in real time by the blasting vibration monitor and hydrophone. If the data exceeds the safety threshold, the charge amount or detonation interval is adjusted immediately. The blasting effect is verified after the blasting. During the blasting process, the blasting vibration monitoring instrument continuously collects vibration velocity data at the protected object, with a sampling frequency of 1000Hz, and the data is transmitted to the control center in real time. The hydrophone collects real-time shock wave pressure data in the water, with a safety threshold set at 0.3 MPa; If the vibration velocity is detected to be greater than 0.5 cm / s or the shock wave pressure is detected to be greater than 0.3 MPa, immediately suspend the subsequent borehole detonation through the remote control system, adjust the charge amount (reduce by 10%-15%) or the detonation interval (increase by 25 ms), and reassess before continuing the operation.

[0051] 24 hours after the blasting is completed, once the underwater sediment has settled and stabilized, a sonar detector is used to conduct a full-coverage survey of the blasting area, measuring the actual excavation bottom elevation and comparing it with the design bottom elevation. Over-excavation ≤ 0.3m and under-excavation ≤ 0.2m are considered acceptable. The size of rock fragments is observed using underwater camera equipment; a maximum fragment size of ≤0.5m is considered acceptable. Organize professional personnel to conduct on-site inspections of the protected objects to check for damage such as cracks, leaks, and displacement. If any abnormalities are found, take remedial measures such as grouting reinforcement and seepage prevention treatment in a timely manner.

[0052] Through the above specific implementation process, precise positioning and accurate depth control of underwater drilling and blasting can be achieved, while ensuring the blasting effect and the safety of the surrounding environment. It is applicable to various underwater blasting projects such as waterway dredging, underwater foundation pit excavation, and reef removal.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for precise positioning and depth control in underwater drilling and blasting, characterized in that, The method includes the following specific steps: S1: Clarify the geological and hydrological conditions and design requirements of the blasting area, determine the core technical parameters, adopt a total station and GPS combined positioning system, adjust the position of the drill and blasting vessel by using a winch, align the drilling rig with the preset blast hole coordinates, and control the positioning deviation within the preset range. S2: The measured water level in the blasting area is collected by a dual-source system of automatic tide meter and water level and pressure sensor. The optimal ultra-deep value is determined by intelligent ultra-deep value decision model. The actual drilling depth is calculated by combining the design bottom elevation. Drilling operation is carried out by down-the-hole drill rig with casing protection. S3: Test blasts are conducted in stages according to the incremental ratio of the designed charge amount. The vibration velocity of the mass points at the protected object is collected by the blasting vibration monitoring instrument. The blasting method is selected based on the monitoring results, and the hole spacing, row spacing, single-stage charge amount and detonation interval are optimized. S4: Process the explosive charge according to the optimized parameters and load it in layers. Set the number and position of the detonators that are suitable for the length of the explosive charge. Use a hole-by-hole delayed detonation network connection. Control the maximum amount of explosive charge in a single stage according to the distance between the protected object and the blasting area. After the explosive charge is plugged, carry out the blasting. S5: During the blasting process, vibration and underwater shock wave data are monitored in real time using a blasting vibration monitor and hydrophone. If the data exceeds the safety threshold, the charge amount or detonation interval is adjusted immediately. The blasting effect is verified after the blasting.

2. The method for precise positioning and depth control in underwater drilling and blasting according to claim 1, characterized in that, In step S1, the geological and hydrological conditions of the blasting area, including lithology, reef thickness, and water depth, are clarified, and the core information such as the design bottom elevation, minimum resistance line, and scope of the protected object are determined in conjunction with the engineering design documents.

3. The method for precise positioning and depth control in underwater drilling and blasting according to claim 1, characterized in that, In step S2, an intelligent ultra-deep value decision model based on the gradient boosting tree algorithm is constructed. The model uses data such as lithology hardness, rock weathering degree, water level change rate, and post-blasting effects from similar historical projects as training samples. The model parameters are iteratively optimized through the gradient boosting tree algorithm. The measured geological and hydrological parameters of the current project, such as lithology, weathering degree, and water level change rate, are input into the model, and the model automatically outputs the optimal ultra-deep value that is suitable for the current working conditions.

4. The method for precise positioning and depth control in underwater drilling and blasting according to claim 3, characterized in that, The formula for the intelligent ultra-deep value decision model is: ,in, The optimal ultradepth value output by the model; These are the initial model predictions. The number of base learners, i.e., the number of decision trees; For the first Weight coefficients of each base learner; For the first Individual base learners, For the input feature vector, For the first The parameters of each base learner include the decision tree split nodes, leaf node output values, and input feature vectors. These correspond to lithological hardness, rock weathering degree, water level change rate, and blasting effect adaptation coefficient, respectively.

5. The method for precise positioning and depth control in underwater drilling and blasting according to claim 4, characterized in that, The input feature vector These correspond to lithological hardness, rock weathering degree, water level change rate, and blasting effect adaptation coefficient, respectively. The uniaxial compressive strength of rock is quantified. After being classified according to geological exploration standards, a quantitative value was assigned: 1.0 for strong weathering, 2.0 for moderate weathering, 3.0 for slight weathering, and 4.0 for unweathered weathering. Based on one hour of continuous monitoring data from dual-source water level acquisition equipment, the result was calculated by dividing the water level change by the monitoring time. The correction coefficient, derived from the reverse calculation of over-excavation and under-excavation amounts after historical engineering blasting, is calculated using the following formula: ,in This represents the actual depth of the historical engineering project. For historical engineering designs, the closer the coefficient is to 1.0, the better the blasting effect of the corresponding ultra-deep value.

6. The method for precise positioning and depth control in underwater drilling and blasting according to claim 1, characterized in that, In step S2, the actual borehole depth is calculated by combining the accurately measured water level, the designed bottom elevation, and the optimal over-depth value output by the intelligent model. The calculation formula is as follows: ,in It is the actual drilling depth. It is an accurate measured water level obtained through dual-source acquisition and collaborative verification. It is the engineering design baseline elevation. It is the optimal ultra-deep value output by the intelligent ultra-deep value decision model; select the drill bit of the corresponding diameter according to the drilling rig model, and before drilling, install the casing to press the ground protection hole opening, start the drilling rig to carry out drilling operations, and the drill rod impact and casing protection are carried out simultaneously during the drilling process.

7. The method for precise positioning and depth control in underwater drilling and blasting according to claim 1, characterized in that, In step S3, test explosions are conducted in stages according to the incremental proportion of the designed charge amount, that is, test explosions are conducted in stages according to 50%, 60%, 70%, and 80% of the designed charge amount, and 3-5 representative boreholes are selected for each test explosion.

8. The method for precise positioning and depth control in underwater drilling and blasting according to claim 1, characterized in that, In step S3, a blasting vibration monitoring instrument is used to collect the particle vibration velocity at the protected object. If the vibration velocity V > 0.5 cm / s, layered blasting is used; if V ≤ 0.5 cm / s, a single blast to the bottom is used.

9. The method for precise positioning and depth control in underwater drilling and blasting according to claim 1, characterized in that, In step S4, a layered charging structure is adopted. When the length of the explosive charge is <3m, one detonator is set at the bottom 1 / 3. When the length of the explosive charge is ≥3m, two detonators are set at the bottom 1 / 4 and 3 / 4 positions. After charging, the borehole is blocked with gravel water bags with a blocking length ≥0.5m.

10. The method for precise positioning and depth control in underwater drilling and blasting according to claim 1, characterized in that, In step S4, a hole-by-hole delayed detonation network is adopted, with a segment interval of 25ms within the hole and an interval of 50ms between holes, controlling the maximum single-segment detonation charge: ≤9kg when the distance to the protected object is 50-70m, ≤15kg when the distance is 70-80m, ≤23kg when the distance is 80-90m, and ≤32kg when the distance is above 90m.

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