Bridge substructure adjacent blasting explosive quantity control optimization method based on blasting center distance dynamic partition

Abstract

The invention discloses a bridge substructure adjacent blasting explosive quantity control optimization method based on blasting center distance dynamic partitioning. The method comprises the steps that 1, a bridge substructure adjacent blasting model is constructed; step 2, determining a Sadgowski formula; 3, blasting zoning is conducted, specifically, a bridge serves as a measuring point, and the blasting zone is divided into a hydraulic crushing zone, an inner deep hole step blasting zone and an outer deep hole step blasting zone according to the sequence of the blasting center distances from small to large; 4, blasting is conducted, specifically, blasting is conducted in each blasting subarea according to a set blasting mode; wherein in the deep hole step blasting process, the maximum vibration velocity of the bridge substructure and the rock crushing effect after blasting are monitored; and 5, dynamically adjusting the maximum explosive quantity of the single section. According to the method, through precise blasting partition, dynamic adjustment of the explosive quantity, a reasonable step height-explosive quantity matching rule and an effective structure safety monitoring feedback mechanism, comprehensive protection on the lower structure of the bridge in the blasting construction process is achieved, and the safety of the bridge structure is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of adjacent blasting construction in bridge engineering, and particularly to an optimized method for controlling the blasting charge of the substructure of a bridge adjacent to a blasting center based on dynamic zoning according to the distance from the blasting center. Background Art

[0002] During the construction of bridge engineering, blasting operations in adjacent areas are extremely common. The conventional method of controlling the blasting charge by dividing the area at a fixed distance has the following drawbacks and needs to be improved.

[0003] 1. The non-linear attenuation characteristics of the structural dynamic response at different distances from the blasting center are not fully considered. The conventional method usually divides the area at a fixed distance (such as 50m, 100m), but does not consider the differences in the vibration attenuation laws under different geological conditions. As a result, the actual vibration effects in different areas at the same distance may far exceed expectations. In actual operation, the blasting charge control may be overly conservative, resulting in low blasting efficiency, increased construction costs and time; or the blasting charge control may be insufficient, causing excessive influence of blasting vibration on the bridge structure and threatening the safety and stability of the bridge.

[0004] 2. The matching between the bench blasting height and the blasting charge is poor. The material strength of the substructure of the bridge (such as pile foundation, pile cap) is not associated with the blasting charge control, which may lead to local stress concentration and cause structural damage, affecting the project quality, and at the same time reducing the construction efficiency.

[0005] 3. The conventional method lacks a dynamic adjustment mechanism based on the strength characteristics of the structural materials. It is unable to flexibly adjust the blasting charge according to the actual situation of the bridge structural materials, such as the concrete strength grade, steel bar configuration, etc., and it is difficult to meet the requirements of fine construction in modern engineering. At the same time, the conventional method cannot adjust the blasting charge in real time through vibration monitoring data, relying on empirical parameters, and it is difficult to cope with sudden geological changes or construction deviations. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an optimized method for controlling the blasting charge of the substructure of a bridge adjacent to a blasting center based on dynamic zoning according to the distance from the blasting center, aiming at the deficiencies of the above-mentioned existing technologies. The optimized method for controlling the blasting charge of the substructure of a bridge adjacent to a blasting center based on dynamic zoning according to the distance from the blasting center realizes the comprehensive protection of the substructure of the bridge during the blasting construction process through accurate blasting zoning, a scientific dynamic adjustment model of the blasting charge, a reasonable matching rule of the bench height - blasting charge, and an effective structural safety monitoring and feedback mechanism, ensures the safety of the bridge structure, improves the blasting construction efficiency, reduces the construction cost, and reduces the impact on the surrounding environment, providing reliable technical support and solutions for similar projects.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is:

[0008] An optimization method for controlling the blasting charge adjacent to the lower structure of a bridge based on dynamic zoning according to the distance from the blast center, comprising the following steps.

[0009] Step 1: Construct a blasting model adjacent to the lower structure of the bridge: Combine the on-site geological exploration data and the construction design data of the lower structure of the bridge, and use finite element analysis software to construct a blasting model adjacent to the lower structure of the bridge.

[0010] Step 2: Determine the Sadovskii formula: The Sadovskii formula includes two unknown blasting coefficients K and the seismic wave attenuation index α; for the blasting model adjacent to the lower structure of the bridge, under different geological conditions and different blasting bench heights, blasting simulations are carried out at different distances r from the blast center, and the maximum vibration velocity v of the lower structure of the bridge is monitored for each blasting; according to the blasting simulation data, the Sadovskii formula is fitted to obtain K and α under each blasting condition.

[0011] Step 3: Blasting zoning: Taking the bridge as the measuring point, the blasting area is divided into a hydraulic crushing area, an inner deep-hole bench blasting area, and an outer deep-hole bench blasting area in the order of increasing distance from the blast center; among them, the inner deep-hole bench blasting area uses Nm deep-hole bench blasting, and the outer deep-hole bench blasting area uses Mm deep-hole bench blasting, and N < M; the initial maximum charge per delay Q in the deep-hole bench blasting is calculated according to the Sadovskii formula determined in Step 2 and the set vibration velocity value of the lower structure of the bridge.

[0012] Step 4: Blasting: In each blasting area, blasting is carried out according to the set blasting method; among them, during the deep-hole bench blasting process, the maximum vibration velocity v of the lower structure of the bridge and the rock fragmentation effect after blasting are monitored.

[0013] Step 5: Dynamically adjust the maximum charge per delay according to the set vibration velocity threshold v0 of the lower structure of the bridge, the blasting monitoring data, and the construction progress.

[0014] In Step 5, the method for dynamically adjusting the charge includes:

[0015] A. When v ≥ v0, reduce the maximum charge per delay Q; where v0 is the set vibration velocity threshold of the lower structure of the bridge.

[0016] B. When v < v0 and the rock fragmentation effect does not meet the standard, increase the maximum charge per delay Q.

[0017] C. When v < v0 and the rock fragmentation effect meets the standard, selectively increase the maximum charge per delay Q according to the construction progress requirements.

[0018] Subsequently, substitute the dynamically adjusted maximum charge per delay Q into the Sadovskii formula determined in Step 2 to calculate the maximum vibration velocity v' of the lower structure of the bridge, and v' < v0.

[0019] In step 3, the range of the distance from the explosion center of the blasting area is as follows:

[0020] For the hydraulic crushing area, the distance from the explosion center r < r1.

[0021] For the inner deep-hole bench blasting area, the distance from the explosion center r1 ≤ r ≤ r2.

[0022] For the outer deep-hole bench blasting area, the distance from the explosion center r > r2.

[0023] r1, r2, r3, as well as N and M, are all obtained based on the safety discrimination of the lower structure of the main bridge by the maximum tensile stress criterion.

[0024] In step 3, the blasting area division method based on the maximum tensile stress criterion includes the following steps:

[0025] Step 3-1: According to the Sadovsky formula determined in step 2, construct the σ-v curve under c kinds of blasting bench heights; where σ is the maximum tensile stress of the lower structure of the bridge corresponding to the distance A from the explosion center, and v is the maximum vibration velocity of the lower structure of the bridge corresponding to the distance A from the explosion center.

[0026] Step 3-2: Using the established σ-v curve, calculate the maximum tensile stress σ of the lower structure of the bridge corresponding to each distance from the explosion center under each blasting bench height.

[0027] Step 3-3: Construct the σ-r curve: with the distance from the explosion center r as the abscissa and the maximum tensile stress σ as the ordinate, construct the σ-r curve of different distances from the explosion center including c kinds of blasting bench heights; where each distance from the explosion center has a set of c maximum tensile stress σ values.

[0028] Step 3-4: In the constructed σ-r curve, add σ = σ0; where σ0 is the tensile strength of the concrete corresponding to the model of the lower structure of the bridge.

[0029] Step 3-5: Denote the minimum distance from the explosion center where the c maximum tensile stress σ values are first separated above and below by σ = σ0 as r1, and denote the blasting bench height corresponding to the maximum maximum tensile stress σ located below σ = σ0 at the distance from the explosion center r1 as N; denote the minimum distance from the explosion center where all c maximum tensile stress σ values are first located below σ = σ0 as r2, and denote the blasting bench height corresponding to the maximum maximum tensile stress σ located below σ = σ0 at the distance from the explosion center r2 as M.

[0030] In step 3-1, the construction method of the σ-v curve is specifically as follows:

[0031] A. Select c different blasting bench heights. For each blasting bench height, select several blast center distances A with different distances. Substitute the blast center distance r where each blast center distance A is located and the corresponding maximum explosive charge Q of the corresponding section into the Sadovskii formula determined in step 2 to obtain the maximum vibration velocity v of each blast center distance A under each blasting bench height.

[0032] B. Construct the σ - v curve equation σ = av + b, where a and b are the fitting coefficients of the maximum tensile stress.

[0033] C. In step 2, when performing blasting simulations for each blast center distance A under each blasting bench height, simultaneously monitor the tensile stress of the lower structure of the bridge in real - time and obtain the maximum tensile stress σ.

[0034] D. Substitute the maximum vibration velocity v and the maximum tensile stress σ of each blast center distance A under c blasting conditions into the constructed curve equation σ = av + b, so as to obtain the σ - v curve with determined a and b under each blasting bench height.

[0035] In step 3 - 1, the c blasting bench heights from small to large are 6m, 8m, and 9m respectively; for each blasting bench height, 5 blast center distances A with different distances are selected, which are 30m, 40m, 50m, 60m, and 70m respectively.

[0036] In step 3 - 5, r1 = 40m, r2 = 50m, N = 8m, M = 9m, so the blasting zones are as follows:

[0037] The hydraulic crushing zone is r < 40m.

[0038] The blast center distance of the inner deep - hole bench blasting zone is 40m ≤ r ≤ 50m, and 8m deep - hole bench blasting is carried out.

[0039] The blast center distance of the outer deep - hole bench blasting zone is r > 50m, and 9m deep - hole bench blasting is carried out.

[0040] The vibration velocity threshold v0 = 8m / s.

[0041] The maximum tensile stress σ of the lower structure of the bridge is located at the joint of the bearing platform and the pile foundation; the maximum vibration velocity of the lower structure of the bridge is located at the bottom of the pile foundation.

[0042] It also includes step 6, updating K and α: When the shape of the rock mass in the blasting zone changes, before blasting, it is necessary to repeat steps 2 to 3 to update K and α and re - adjust the blasting zone.

[0043] The present invention has the following beneficial effects:

[0044] (1) The refined modeling technology of the present invention is used for the design of precise blasting parameters. By combining geology, bridge structure, and blasting conditions, the vibration velocity attenuation parameters K and α are determined, enabling the accurate understanding of the propagation law of blasting vibration in specific geology and bridge structures. This provides a scientific basis for blasting zoning and charge control, significantly improving the accuracy and reliability of blasting parameter design, adapting to complex engineering environments, and providing core technology for bridge safety.

[0045] (2) The dynamic zoning and intelligent charge regulation system of the present invention: Based on the dynamic zoning strategy and intelligent charge regulation method based on the distance from the blast center, it significantly improves traditional blasting. Reasonable blasting zoning reduces the risk of damage to the bridge caused by high-intensity blasting. According to the distance between the bridge and the blast source, the operation area is divided and differential blasting parameters are formulated to accurately control the blasting impact. Different construction methods and blasting parameters are adopted for different blasting zones, achieving hierarchical protection of the bridge structure and ensuring the safety and stability of the bridge. During construction, the charge is calculated and dynamically adjusted in combination with the rock properties, bench height, and allowable vibration velocity, balancing safety and efficiency.

[0046] (3) The closed-loop feedback safety guarantee mechanism realizes the dynamic monitoring of blasting construction through real-time monitoring and adjustment. Sensors are arranged at key parts of the bridge to collect and analyze vibration data in real time. Once a safety risk is detected, adjustment measures are immediately triggered. This mechanism quickly responds to construction changes, effectively preventing accidents, improving the safety and reliability of construction, and providing new ideas for the safety management of bridge blasting construction. This method has wide applicability and can be applied to blasting construction projects in the vicinity of various bridges, providing an efficient and safe blasting construction technical solution for the industry, promoting the development of blasting construction technology near bridge engineering, and having significant economic and social benefits. Description of the Drawings

[0047] Figure 1 Shows a three-dimensional view of the blasting model adjacent to the lower structure of the bridge in the present invention.

[0048] Figure 2 Shows the layout diagram of blast holes at different blast source orientations and different distances from the blast center in the blasting model adjacent to the lower structure of the bridge.

[0049] Figure 3 Shows the structural schematic diagram of the lower structure of the bridge after meshing.

[0050] Figure 4 Shows the schematic diagram of the Sadovskii curve determined in the present invention.

[0051] Figure 5 Shows the monitoring schematic diagram of the maximum vibration velocity of the lower structure of the bridge in the present invention; among them, (a) is the schematic diagram of the measuring line for arranging vibration velocity sensors; (b) is the vibration velocity curve on the blast-facing side; (c) is the vibration velocity curve on the non-blast-facing side.

[0052] Figure 6 Shows the monitoring schematic diagram of the maximum tensile stress of the bridge substructure in the present invention; among them, (a) is the three-dimensional simulation schematic diagram of the tensile stress; (b) is the tensile stress curve diagram on the blast-facing side; (c) is the tensile stress curve diagram on the non-blast-facing side.

[0053] Figure 7 Shows the σ-v curve constructed in this embodiment.

[0054] Figure 8 Shows the σ-r curve constructed in this embodiment.

[0055] Figure 9 Shows the schematic diagram of the blasting partition in this embodiment.

[0056] Among them:

[0057] 10. Canal bank slope; 20. Foundation pit of bearing platform;

[0058] 30. Bridge substructure; 31. Pile foundation; 32. Bearing platform; 33. Pier column; 34. Split beam;

[0059] 40. Rock mass to be blasted; 41. Blasthole. Specific implementation method

[0060] The present invention will be further described in detail below with reference to the drawings and specific preferred embodiments.

[0061] An optimization method for controlling the blasting charge adjacent to the bridge substructure based on the dynamic partition of the distance from the blast center includes the following steps.

[0062] Step 1, construct a blasting model adjacent to the bridge substructure

[0063] Combined with the on-site geological exploration data and the construction design data of the bridge substructure, use finite element analysis software to construct a blasting model adjacent to the bridge substructure as shown in Figure 1 the figure.

[0064] Figure 1According to the "Construction Drawings of Qishi Hub and Upstream and Downstream Waterways Project of the Western Land-Sea New Corridor (Pinglu) Canal (K30+561~K50+037)", a three-dimensional finite element model of the lower structure of the main bridge of Luyang Xincun Bridge, the foundation pit of the bearing platform, and the canal bank slope under the influence of blasting excavation is established and solved using ANSYS / LS-DYNA. The finite element model of the lower structure of the bridge adjacent to the blasting includes a three-dimensional finite element model of the canal bank slope 10, the foundation pit of the bearing platform 20, the lower structure of the bridge 30, and the rock mass to be blasted 40. The lower structure of the bridge is set in the foundation pit of the bearing platform, the foundation pit of the bearing platform is located on the canal bank slope, and blast holes are set in the rock mass to be blasted 40 as the blast source. In the finite element model of the lower structure of the bridge adjacent to the blasting, areas of different materials such as concrete, steel bars, strongly weathered silty mudstone, and moderately weathered silty mudstone need to be marked, and their respective material parameters are indicated. Through this figure, technicians can intuitively understand the construction method of the model and the attributes of each part, providing support for understanding subsequent simulation analysis.

[0065] Figure 2 It is a schematic diagram after the mesh division of the finite element model of the lower structure of the bridge adjacent to the blasting. The mesh size of each part of the model is preferably 50 cm. The steel bars and the rock mass are divided by solid elements, and the steel bars are divided by rod elements. A total of 5.4 million solid elements and 250,000 rod elements are divided. Further, Figure 2 It shows a schematic diagram of the positions of the blast holes in different orientations and the distances from the blast center in the rock mass to be blasted. Through data simulation analysis, the influence of the blast source orientation on the dynamic response of the lower structure of the bridge is very small. Therefore, this invention focuses on studying the influence of different distances from the blast center on the dynamic response of the lower structure of the bridge.

[0066] Figure 3 It is a schematic diagram of the structure of the lower structure of the bridge after mesh division, which includes a tie beam 34 and support structures on both sides of the tie beam; each support structure includes a pile foundation 31, a bearing platform 32, and a pier column 33 arranged in sequence from bottom to top; the tie beam, pile foundation, bearing platform, and pier column all include concrete and embedded steel bar elements; during the modeling process, the coupling effect between the concrete and the steel bar elements is adopted using the CONSTRAINT_LAGRANGIAN_IN_SOLID keyword; the rock mass adopts the Mohr-Coulomb material model; due to the irregular arrangement of the pier columns, bearing platforms, and pile foundations in the lower structure, which is not convenient for mesh division, the CONTACT_TIED_SURFACE_TO_SURFACE keyword is used to set full bonding between the pier column and the bearing platform, rather than using the method of sharing nodes; the blasting load is preferably an equivalent triangular load.

[0067] Step 2: Determine the Sadovskii formula

[0068] The Sadovskii empirical formula shows that the vibration velocity of the measuring point is related to the distance from the measuring point to the blast source and the maximum charge amount per delay section, and is also significantly related to factors such as the geology of the blasting area and the blasting method, that is:

[0069]

[0070] In the formula, K is the blasting coefficient, which is related to factors such as the geology of the blasting area and the blasting method, and is an unknown coefficient to be determined.

[0071] v is the maximum vibration velocity of the lower structure of the bridge.

[0072] Q is the maximum charge amount per delay; r is the distance from the blast center.

[0073] α is the seismic wave attenuation index, which is an unknown coefficient to be determined.

[0074] For the blasting model adjacent to the lower structure of the bridge, under different geological conditions and different blasting bench heights, blasting simulations with different distances r from the blast center are carried out respectively, and the maximum vibration velocity v of the lower structure of the bridge is monitored for each blasting; according to the blasting simulation data, the Sadovsky formula is fitted to obtain K and α under each blasting condition.

[0075] In this embodiment, under the set geological conditions and the set blasting bench height, the maximum vibration velocity of the lower structure of the main bridge at five different distances from the blast center (20m, 30m, 40m, 50m, and 60m) is calculated numerically, and the attenuation law of the vibration velocity of the lower structure with the distance from the blast center can be obtained by fitting in the form of a power function. The specific curve relationship is as Figure 4 shown.

[0076] As Figure 5 shown, the symmetric centerlines of the blast-facing side and the non-blast-facing side of the lower structure of the bridge are used as the measurement lines. As shown in (a) of Figure 5 , vibration velocity sensors are arranged sequentially from top to bottom at the measurement lines (where the top surface of the pier column is recorded as the height of the vertical coordinate 0). After the simulated blasting, the vibration velocity curves shown in (b) and (c) of Figure 5 are obtained. Since the pile foundation is embedded in the rock mass and is directly affected by the blasting stress wave of the rock mass, the influence of the stress wave on the lower structure of the main bridge is mainly concentrated on the pile foundation part. As the depth increases, the peak vibration velocity (i.e., the maximum vibration velocity) of the pile matrix gradually increases as a whole and reaches the maximum value at the bottom. The vibration velocity of the pier body is relatively small, but a certain degree of vibration velocity amplification effect can be observed at the top of the pier column.

[0077] Step 3, Blasting zoning: Taking the bridge as the measurement point, the blasting area is divided into a hydraulic crushing area, an inner deep-hole bench blasting area, and an outer deep-hole bench blasting area in the order of increasing distance from the blast center; among them, the inner deep-hole bench blasting area adopts Nm deep-hole bench blasting, and the outer deep-hole bench blasting area adopts Mm deep-hole bench blasting, and N < M; the initial maximum charge amount Q per delay in the deep-hole bench blasting is calculated according to the Sadovsky formula determined in Step 2 and the set vibration velocity value of the lower structure of the bridge.

[0078] In Step 3, the range of the distance from the blast center of the blasting area is as follows:

[0079] For the hydraulic crushing area, the distance from the blast center r < r1.

[0080] For the inner deep-hole bench blasting area, the distance from the blast center r1 ≤ r ≤ r2.

[0081] For the outer deep-hole bench blasting area, the distance from the blast center r > r2.

[0082] In this embodiment, the above r1, r2, and r3, as well as N and M, are preferably obtained based on the safety discrimination of the lower structure of the main bridge according to the maximum tensile stress criterion, and specifically include the following steps.

[0083] Step 3-1: According to the Sadovsky formula determined in Step 2, construct σ-v curves for c blasting bench heights; where σ is the maximum tensile stress of the lower structure of the bridge corresponding to the distance from the blast center A, and v is the maximum vibration velocity of the lower structure of the bridge corresponding to the distance from the blast center A. The c blasting bench heights are preferably 6 m, 8 m, and 9 m from small to large; at each blasting bench height, 5 distances of the blast center A with different distances are selected, preferably 30 m, 40 m, 50 m, 60 m, and 70 m respectively.

[0084] The construction method of the above σ-v curve is specifically as follows:

[0085] A. Select c different blasting bench heights. At each blasting bench height, select several blast center distances A with different distances. Substitute the blast center distance r where each blast center A is located and the maximum explosive charge Q of the corresponding section into the Sadovsky formula determined in Step 2 to obtain the maximum vibration velocity v of each blast center A at each blasting bench height.

[0086] B. Construct the σ-v curve equation σ = av + b, where a and b are the maximum tensile stress fitting coefficients.

[0087] C. In Step 2, when performing blasting simulation for each blast center A at each blasting bench height, simultaneously monitor the tensile stress of the lower structure of the bridge in real time and obtain the maximum tensile stress σ.

[0088] As Figure 6 shown, stress sensors are arranged successively from top to bottom at the measuring lines on the blast-facing side and the back-blast side of the lower structure of the bridge (where the top surface of the pier column is recorded as the vertical coordinate 0 height), Figure 5 as shown in (a) in Figure 6 shows the stress simulation change diagram after the simulated blasting. The stress change curve is as shown in (b) and (c) in

[0089] D. Substitute the maximum vibration velocity \(v\) and the maximum tensile stress \(\sigma\) of each blast center distance \(A\) under the \(c\) blasting conditions into the constructed curve equation \(\sigma = av + b\), so as to obtain the \(\sigma - v\) curve with determined \(a\) and \(b\) under each blasting bench height. In this embodiment, by fitting the maximum tensile stress and the maximum vibration velocity of the lower structure of the main bridge in the numerical model, the \(\sigma - v\) curve as shown in Figure 7 can be obtained.

[0090] Step 3 - 2: Use the established \(\sigma - v\) curve to calculate the maximum tensile stress \(\sigma\) of the bridge lower structure corresponding to each blast center distance under each blasting bench height.

[0091] Step 3 - 3: Construct the \(\sigma - r\) curve: Take the blast center distance \(r\) as the abscissa and the maximum tensile stress \(\sigma\) as the ordinate to construct the \(\sigma - r\) curve of different blast center distances including \(c\) blasting bench heights; among them, each blast center distance has a set of \(c\) maximum tensile stress \(\sigma\) values. The \(\sigma - r\) curve constructed in this embodiment is as shown in Figure 7 below.

[0092] Step 3 - 4: In the constructed \(\sigma - r\) curve, add \(\sigma=\sigma_0\) to form the \(\sigma - r\) curve as shown in Figure 8 below. Where \(\sigma_0\) is the tensile strength of the concrete corresponding to the bridge lower structure.

[0093] Step 3 - 5: Denote the minimum blast center distance at which the \(c\) maximum tensile stress \(\sigma\) values are first separated by \(\sigma=\sigma_0\) as \(r_1\), and denote the blasting bench height corresponding to the maximum tensile stress \(\sigma\) that is below \(\sigma=\sigma_0\) and the largest at the blast center distance \(r_1\) as \(N\); denote the minimum blast center distance at which the \(c\) maximum tensile stress \(\sigma\) values are all below \(\sigma=\sigma_0\) for the first time as \(r_2\), and denote the blasting bench height corresponding to the maximum tensile stress \(\sigma\) that is below \(\sigma=\sigma_0\) and the largest at the blast center distance \(r_2\) as \(M\).

[0094] In this embodiment, from Figure 8 it can be seen that when the horizontal blast center distance is equal to 40 m, the maximum tensile stress generated by the 9 - m bench blasting exceeds the tensile strength of the concrete; when the horizontal blast center distance is less than 40 m, the maximum tensile stress generated by the 8 - m and 6 - m bench blasts also exceeds the tensile strength of the concrete. Therefore, when the horizontal blast center distance is less than 40 m, that is, \(r_1 = 40\) m, it is recommended to start using the hydraulic crushing method. Further, \(r_2 = 50\) m, \(N = 8\) m, \(M = 9\) m, so the blasting zones are as follows:

[0095] The hydraulic crushing zone is \(r\lt40\) m.

[0096] For the inner deep - hole bench blasting zone, the blast center distance is \(40\) m \(\leq r\leq50\) m, and 8 - m deep - hole bench blasting is carried out.

[0097] For the outer deep - hole bench blasting zone, the blast center distance is \(r\gt50\) m, and 9 - m deep - hole bench blasting is carried out.

[0098] In the inner deep-hole bench blasting area, when blasting is required in an area 45 m away from a bridge, 8-m bench blasting is adopted. According to the rock hardness on-site and other conditions, the charge per hole is initially set at 19 kg, the hole spacing is 3.0 m, and the row spacing is 3.0 m.

[0099] High-precision stress sensors and vibration sensors are arranged at key stress concentration areas such as the bridge pile foundation-cap connection. Compared with the traditional method of randomly placing points only on the bridge surface, the point-placement strategy of this patent can more accurately capture the vibration response of the weak parts of the structure. For example, when blasting in the inner deep-hole bench blasting area, the vibration velocity sensor monitors in real time that the vibration velocity of a certain section is close to the threshold value (such as 8 cm / s), and the system automatically triggers the charge correction mechanism, adjusts the charge per hole of the subsequent blasting from 19 kg to 17 kg, and increases the initiation delay time, successfully controlling the vibration velocity within the safe range. Through dense point-placement and real-time feedback, this application realizes the refined monitoring of the structural response and avoids the potential safety hazards caused by monitoring blind spots in the traditional method. In the outer deep-hole bench blasting area, for an area 60 m away from the bridge, 9-m bench blasting is adopted, and the charge per hole is calculated as 30 kg according to the rock hardness, bench height and Sadovskii formula, the hole spacing is 3.0 m, and the row spacing is 3.5 m.

[0100] Step 4, Blasting: In each blasting area, blasting is carried out according to the set blasting method; among them, during the deep-hole bench blasting process, the maximum vibration velocity v of the bridge substructure and the rock fragmentation effect after blasting are monitored.

[0101] Step 5, Dynamically adjust the maximum charge per section according to the set vibration velocity threshold v0 of the bridge substructure, blasting monitoring data and construction progress.

[0102] In step 5, the method for dynamically adjusting the charge includes:

[0103] A. When v≥v0, reduce the maximum charge per section Q; where v0 is the set vibration velocity threshold of the bridge substructure. In this embodiment, preferably, the vibration velocity threshold v0 = 8 m / s.

[0104] B. When v<v0 and the rock fragmentation effect does not meet the standard, increase the maximum charge per section Q.

[0105] C. When v<v0 and the rock fragmentation effect meets the standard, selectively increase the maximum charge per section Q according to the construction progress requirements.

[0106] Subsequently, substitute the dynamically adjusted maximum charge per section Q into the Sadovskii formula determined in step 2 to calculate the maximum vibration velocity v' of the bridge substructure, and v'<v0.

[0107] Step 6, update K and α: When the shape of the rock mass in the blasting area changes, before blasting, Steps 2 to 3 need to be repeated to update K and α and readjust the blasting area, that is, to achieve dynamic zoning of the distance from the blast center.

[0108] During the entire construction process, the vibration data is monitored in real time using a monitoring system, and the monitoring data is analyzed and summarized every 3 to 5 blasts. If it is found that the rock hardness in a certain area is greater than expected, resulting in an unsatisfactory blasting effect, on the premise of ensuring vibration safety, the single-hole charge amount for subsequent blasting in this area is appropriately increased to 31 kg, and at the same time, the monitoring points are encrypted to ensure the safety of the bridge structure. Compared with the extensive operation of the traditional method with a fixed charge amount, this patent realizes the optimal balance between safety and efficiency through a triple mechanism of "formula calculation + real-time verification + dynamic adjustment".

[0109] Through this method of real-time monitoring and dynamic adjustment, the present invention not only ensures the structural safety of the bridge during the blasting construction process, but also improves the blasting construction efficiency. Compared with the traditional construction method, the construction period is shortened, and at the same time, the potential damage that may be caused to the bridge by blasting vibration is reduced, and the later maintenance cost is lowered.

[0110] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A method for optimizing the amount of explosives to be blasted near a bridge substructure based on dynamic zoning of the distance to the blast center, characterized in that: The steps include: Step 1: Construct a blasting model near the bridge substructure: Combine the on-site geological survey data and the construction design data of the bridge substructure, and use finite element analysis software to construct a blasting model near the bridge substructure; Step 2, determine the Sadovsky formula: The Sadovsky formula includes two unknown blasting coefficients K and seismic wave attenuation index α; for the bridge substructure adjacent blasting model, blasting simulations with different blasting center distances r are performed under different geological conditions and different blasting step heights, and the maximum vibration velocity v of the bridge substructure is monitored for each blasting; based on the blasting simulation data, the Sadovsky formula is fitted to obtain K and α under each blasting condition; Step 3, blasting zoning: taking the bridge as the measuring point, the blasting area is divided into a hydraulic crushing area, an inner deep hole step blasting area and an outer deep hole step blasting area in the order of the distance from the blasting center from small to large; wherein, the inner deep hole step blasting area adopts Nm deep hole step blasting, and the outer deep hole step blasting area adopts Mm deep hole step blasting, and N<M; the initial single-stage maximum explosive quantity Q in the deep hole step blasting is calculated according to the Sadovsky formula determined in step 2 and the set vibration velocity value of the bridge substructure; Step 4, blasting: in each blasting zone, blasting is performed according to the set blasting method; in the process of deep hole step blasting, the maximum vibration velocity v of the bridge substructure and the rock crushing effect after blasting are monitored; Step 5: According to the set vibration velocity threshold v0 of the bridge substructure, blasting monitoring data and construction progress, the maximum amount of explosives in a single section is dynamically adjusted.

2. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the explosion center distance according to claim 1 is characterized in that: In step 5, the method for dynamically adjusting the drug dosage includes: A. When v ≥ v0, reduce the maximum explosive quantity Q in a single section; where v0 is the set vibration velocity threshold of the bridge substructure; B. When v<v0 and the rock crushing effect is not up to standard, increase the maximum amount of explosives Q in a single stage; C. When v<v0 and the rock crushing effect meets the standard, the single-stage maximum explosive quantity Q is selectively increased according to the construction progress requirements; then, the dynamically adjusted single-stage maximum explosive quantity Q is substituted into the Sadovsky formula determined in step 2 to calculate the maximum vibration velocity v' of the bridge substructure, and v'<v0.

3. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the distance from the explosion center according to claim 1 is characterized by: In step 3, the blast center distance range of the blasting partition is: The explosion center distance of the hydraulic crushing area is r<r1; The blasting center distance in the inner deep hole step blasting area is r1≤r≤r2; The blasting center distance of the outer deep hole step blasting area is r>r2; r1, r2 and r3, as well as N and M, are obtained based on the safety judgment of the main bridge substructure based on the maximum tensile stress criterion.

4. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the explosion center distance according to claim 3 is characterized in that: In step 3, the blasting zoning method based on the maximum tensile stress criterion includes the following steps: step 3-1, according to the Sadovsky formula determined in step 2, constructing a σ-v curve under c kinds of blasting step heights; wherein σ is the maximum tensile stress of the bridge substructure corresponding to the explosion center distance A, and v is the maximum vibration velocity of the bridge substructure corresponding to the explosion center distance A; step 3-2, using the established σ-v curve, calculating the maximum tensile stress σ of the bridge substructure corresponding to each explosion center distance under each blasting step height; Step 3-3, constructing a σ-r curve: with the explosion center distance r as the horizontal coordinate and the maximum tensile stress σ as the vertical coordinate, construct a σ-r curve of different explosion center distances including c kinds of blasting step heights; wherein each explosion center distance has a set of c maximum tensile stress σ values; Step 3-4: Add σ=σ0 to the constructed σ-r curve; where σ0 is the tensile strength of the corresponding concrete type of the bridge substructure; Step 3-5, record the minimum explosion center distance at which c maximum tensile stress σ values ​​are first separated by σ=σ0 as r1, and record the blasting step height corresponding to the maximum tensile stress σ at the explosion center distance r1 which is below σ=σ0 and has the largest value as N; record the minimum explosion center distance at which c maximum tensile stress σ values ​​are first all located below σ=σ0 as r2, and record the blasting step height corresponding to the maximum tensile stress σ at the explosion center distance r2 which is below σ=σ0 and has the largest value as M.

5. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the distance from the explosion center according to claim 4 is characterized in that: In step 3-1, the method for constructing the σ-v curve is as follows: A. Select c different blasting step heights. Under each blasting step height, select several unequal distances A from the center of blast. Substitute the center of blast r and the corresponding maximum explosive quantity Q of each blast center distance A into the Sadovsky formula determined in step 2 to obtain the maximum vibration velocity v of each blast center distance A under each blasting step height. B. Construct the σ-v curve equation σ=av+b, where a and b are the maximum tensile stress fitting coefficients; C. In step 2, when blasting simulation is performed for each blasting center distance A at each blasting step height, the tensile stress of the bridge substructure is monitored in real time, and the maximum tensile stress σ is obtained; D. Substitute the maximum vibration velocity v and the maximum tensile stress σ at each explosion center distance A under c types of blasting conditions into the constructed curve equation σ=av+b, so as to obtain a σ-v curve with a certain a and b under each blasting step height.

6. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the distance from the explosion center according to claim 5 is characterized by: In step 3-1, the heights of the c types of blasting steps are 6m, 8m and 9m from small to large; under each blasting step height, 5 blasting center distances A with different distances are selected, which are 30m, 40m, 50m, 60m and 70m respectively; In step 3-5, r1 = 40m, r2 = 50m, N = 8m, M = 9m, so the blasting partition is: The hydraulic crushing area is r<40m; The blasting center distance in the inner deep hole step blasting area is 40m≤r≤50m, and the blasting is done in 8m deep hole step; The blasting center distance r in the outer deep hole step blasting area is greater than 50m, and the blasting is done in a 9m deep hole step.

7. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the explosion center distance according to claim 1 is characterized in that: Vibration velocity threshold v0=8m / s.

8. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the distance from the explosion center according to claim 1 is characterized by: In step 1, ANSYS / LS-DYNA is used to establish a bridge substructure adjacent blasting model, which includes a bridge substructure set in a cap foundation pit; the bridge substructure includes a tie beam and supporting structures located on both sides of the tie beam; each supporting structure includes pile foundations, caps and piers arranged from bottom to top; the tie beam, pile foundation, cap and pier all include concrete and steel units built into the concrete; in the process of establishing the bridge substructure adjacent blasting model, the rock mass adopts the Mohr-Coulomb material model; the coupling effect between concrete and steel units adopts the CONSTRAINT_LAGRANGIAN_IN_SOLID keyword; the CONTACT_TIED_SURFACE_TO_SURFACE keyword is used for full bonding setting between the pier and the cap; the blasting load adopts a triangular equivalent load.

9. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the distance from the explosion center according to claim 8 is characterized by: The maximum tensile stress σ of the bridge substructure is located at the junction of the cap and the pile foundation; the maximum vibration velocity of the bridge substructure is located at the bottom of the pile foundation.

10. The method for optimizing the amount of explosives to be blasted near the bridge substructure based on dynamic zoning of the distance from the explosion center according to claim 1 is characterized by: The method also includes step 6, updating K and α: when the shape of the rock mass in the blasting partition changes, before blasting, steps 2 to 3 need to be repeated to update K and α and readjust the blasting partition.

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