A safe evaluation and analysis method for harmful effects of subway tunnel blasting

Abstract

The present application relates to the technical field of blasting construction, and in particular to a method for safety evaluation and analysis of harmful effects of metro tunnel blasting, comprising: based on the tunnel contour line, monitoring points are arranged along the axial and radial directions of the tunnel to obtain real-time blasting data of the metro tunnel blasting; according to the spatial position corresponding to the last blasting section, the damage range and damage intensity of each blasting are defined; according to the damage intensity of each monitoring point in the damage range, the damage intensity is processed according to the single-point blasting effect and the multi-point superposition blasting effect to construct the spatial mapping relationship corresponding to each monitoring point; based on the spatial mapping relationship of each monitoring point, the harmful effect state of each monitoring point is identified, and when the harmful effect state of the monitoring point is the activated state, the propagation path between the monitoring points is constructed; the data on the propagation path is coupled and correlated, and the output times of the monitoring points in the propagation path are used to generate the judgment level of the harmful effect. The accuracy and efficiency of the analysis of the harmful effects of blasting are improved.

Description

Technical Field

[0001] This invention relates to the field of blasting construction technology, specifically a method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels. Background Technology

[0002] Urban subway tunnels are located near sensitive protected targets such as residential buildings, hospitals, cultural heritage sites, and high-pressure gas pipelines, necessitating strict control over the harmful effects of blasting operations, including damage to the surrounding rock and vibration impacts. Existing technologies mostly rely on signal processing algorithms and statistical analysis techniques for data preprocessing and threshold judgment. While these methods can detect anomalies to some extent, they are prone to problems such as redundant range analysis, missing damage analysis dimensions, and low data coupling efficiency when dealing with the complex and variable blasting environment of subway tunnels.

[0003] For example, Chinese Patent Publication No. CN119989245A discloses an anomaly analysis method and system based on blasting data. The method includes: collecting blasting data from various monitoring nodes, dividing the monitoring nodes into multiple regions, calculating the anomaly density of each region within a preset historical period, and dynamically setting the region weights of the autoencoder training samples based on the anomaly density; reconstructing the current round of data using the weighted autoencoder, calculating the residual of each node, and extracting the activation path information of nodes whose residuals exceed the initial screening threshold of the reconstruction error; constructing a graph structure model between monitoring nodes, calculating the anomaly propagation path based on the correlation between nodes; and matching the activation path with the propagation path to determine the anomaly state of the target node.

[0004] For example, Chinese Patent Publication No. CN119939921A discloses an intelligent blasting-aided design system and method based on terrain simulation technology, which includes: constructing a visual data model of the area to be blasted based on the terrain data of the area to be blasted; locating several blasting locations according to the blasting purpose; finding each blasting location and conducting blasting tests; obtaining the blasting response data corresponding to each blasting location and inputting it into the visual data model; generating a blasting operation plan in combination with the blasting purpose; when blasting operations are carried out in the area to be blasted, real-time blasting information generates corresponding blasting results in the visual data model and displays them; determining the deviation characteristics of the blasting results corresponding to each blasting location; generating and displaying auxiliary blasting suggestions for blasting operations; and assisting in blasting location by performing terrain simulation.

[0005] In existing technologies, path reconstruction analysis through data sampling is used to take data similarity as the main subject of blasting data analysis; or the required blasting force is adjusted and displayed based on the implementation results of the blasting location. However, existing technologies tend to be threshold-based triggering processes for discrete monitoring points, which cannot dynamically adjust the monitoring range as the blasting process progresses. This makes it impossible to couple the global blasting effect based on the damage range of each blast, thereby reducing the accuracy of the assessment of the harmful effects of blasting. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a safety evaluation and analysis method for the harmful effects of blasting in subway tunnels, comprising: S1, based on the tunnel outline, setting up monitoring points along the tunnel axis and radial direction to obtain real-time blasting data of subway tunnel blasting; the real-time blasting data includes vibration velocity, vibration frequency and vibration duration.

[0007] S2, based on the spatial location corresponding to the previous blasting section, defines the damage range and damage intensity of each monitoring point during each blast.

[0008] S3. Based on the damage intensity of each monitoring point within the damage range, the damage intensity is processed according to the single-point blasting effect and the multi-point superimposed blasting effect, and a spatial mapping relationship is constructed for each monitoring point.

[0009] S4. Based on the spatial mapping relationship of each monitoring point, identify the harmful effect status of each monitoring point. When the harmful effect status of a monitoring point is active, construct the propagation path between monitoring points.

[0010] S5 performs coupling correlation on the data along the propagation path, and generates the judgment level of harmful effects by using the number of outputs of monitoring points within the propagation path.

[0011] The beneficial effects of this invention are as follows: First, this invention uses the spatial location of the blasting section as a benchmark to define the damage range and damage intensity of the monitoring point corresponding to a single blast; it divides the damage range according to radial and axial dimensions, using the ratio of the length of the damage range in different directions to the equivalent radius of the section as a spatial constraint feature, and outputs the convergent damage range boundary through multiple iterations; it constructs a vibration spectrum diagram based on monitoring data, extracts the dominant frequency through frequency domain analysis, and outputs the damage intensity using the spectral energy ratio and spectral acceleration corresponding to the dominant frequency. This clarifies the continuous definition method of the damage range during the tunnel excavation process and avoids the problems of missed or missing damage ranges through iterative convergence of spatial constraint features; finally, it uses spectral energy to correlate with the actual damage, improving the accuracy of damage identification.

[0012] II. This invention constructs a spatial mapping relationship corresponding to monitoring points by processing single-point blasting effects and multi-point superimposed blasting effects separately; it segments and windows real-time data based on blasting delay time, and marks the damage range and intensity corresponding to each segment according to the detonation sequence; for single-point blasting effects, it fits the damage intensity decay law of a single segment and sets a single-point effect zone; for multi-point superimposed blasting effects, it calculates the proportion of single-segment damage increment to form a damage contribution matrix, and sets a multi-point superimposed effect zone with the intersection area of ​​multiple segment damage ranges as the main body; finally, the spatial mapping relationship is set. The contribution ratio of each detonation segment to the surrounding rock damage is located through damage contribution; the spatial distribution form and relative descriptive dimension of the current data are clarified, realizing the integration and interpretability of effect zoning.

[0013] Third, this invention identifies the state of harmful effects based on the spatial mapping relationship of monitoring points, and constructs propagation paths between monitoring points in the active state. First, monitoring points are connected to form an initial propagation path. Using a safety threshold as a standard, when monitoring point parameters are abnormal, an abnormal activation state is entered, constructing a negative safety contribution propagation path; when all parameters are normal, a normal activation state is entered, constructing a positive safety contribution propagation path. In the abnormal activation state, the path difference between the current state and the previous abnormal activation state is calculated, and it is determined whether it matches the previous abnormal region. If they match, the propagation path is output according to the update time sequence; otherwise, the propagation path is reconstructed based on the path difference combination. This realizes a data evolution method under risk diffusion, providing data basis for risk tracing and targeted control, making the propagation process of harmful effects visible, and improving the efficiency of handling harmful effects. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a flowchart illustrating a safety evaluation and analysis method for the harmful effects of blasting in subway tunnels.

[0016] Figure 2 This is a flowchart illustrating step S2 of a safety evaluation and analysis method for the harmful effects of blasting in subway tunnels.

[0017] Figure 3 This is a flowchart illustrating step S3 of a safety evaluation and analysis method for the harmful effects of blasting in subway tunnels.

[0018] Figure 4 This is a flowchart illustrating step S4 of a safety evaluation and analysis method for the harmful effects of blasting in subway tunnels.

[0019] Figure 5 This is a flowchart illustrating step S5 of a safety evaluation and analysis method for the harmful effects of blasting in subway tunnels. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product manual.

[0021] See Figure 1 A safety evaluation and analysis method for the harmful effects of blasting in subway tunnels includes: S1, based on the tunnel outline, setting up monitoring points along the tunnel axis and radial direction to obtain real-time blasting data of subway tunnel blasting; the real-time blasting data includes vibration velocity, vibration frequency and vibration duration.

[0022] S2 defines the damage range and intensity of each monitoring point during each blast, based on the spatial location corresponding to the previous blasting section. Here, the previous blasting section refers to the tunnel excavation section completed in the previous blasting cycle, used to illustrate the data analysis process related to the results of multiple blasts.

[0023] S3. Based on the damage intensity of each monitoring point within the damage range, the damage intensity is processed according to the single-point blasting effect and the multi-point superimposed blasting effect, and a spatial mapping relationship is constructed for each monitoring point.

[0024] S4. Based on the spatial mapping relationship of each monitoring point, identify the harmful effect status of each monitoring point. When the harmful effect status of a monitoring point is active, construct the propagation path between monitoring points.

[0025] S5 performs coupling correlation on the data along the propagation path, and generates the judgment level of harmful effects by using the number of outputs of monitoring points within the propagation path.

[0026] In the blasting construction of subway tunnels, the stress waves generated by the blasting propagate radially and axially throughout the tunnel surrounding rock. After being superimposed in time and space by the micro-differential detonation of multiple blast holes, they form a cyclic dynamic loading on the surrounding rock outside the outline. When the tensile stress generated by the loading exceeds the tensile strength of the rock, it will cause structural damage such as the expansion of surrounding rock fissures, the initiation and connection of new fissures, and the deterioration of rock mass integrity, which are the harmful effects of construction.

[0027] It should be noted that the above-mentioned blasting cross-section represents the excavation cross-section completed in the previous blasting cycle, representing the spatial location where blasting has been completed. It will serve as the basis for analysis of subsequent blasting and define the implementation process of subsequent blasting.

[0028] In one embodiment of the present invention, step S1 is used to determine the spatial location of each blast and collect real-time blasting data within the corresponding spatial range according to the tunnel outline of the blasting design.

[0029] Furthermore, real-time blasting data includes the vibration velocity, vibration frequency, and vibration duration corresponding to the explosion vibration wave. By statistically analyzing the data from each monitoring point, data from the area where multiple monitoring points are located is aggregated.

[0030] In the current scheme, vibration sensors are deployed at various locations in the tunnel structure to obtain the radial and axial components of the vibration velocity, and the vibration duration and frequency under the corresponding scenario are recorded simultaneously to quantify the vibration situation corresponding to all blasting.

[0031] One implementation of step S1 includes: selecting the monitoring point closest to the blasting section as the initial monitoring point based on the monitoring points arranged radially and axially in the tunnel, and gradually expanding along the axial and radial positions of the initial monitoring point to determine the number of monitoring points corresponding to the current blasting section.

[0032] The number of identified monitoring points is divided according to the range of values ​​for vibration velocity, vibration frequency, and vibration duration, forming multiple sets of data corresponding to the monitoring points.

[0033] Furthermore, the number of monitoring points represents the physical boundary of the current data monitoring. By synchronizing the monitoring points with the parameter values, it is possible to divide the levels under different values, thereby quantifying the damage range.

[0034] Furthermore, based on the excavation section completed by the previous blasting cycle, at least two monitoring sections are set up in front of the tunnel excavation direction along the axial direction, and at least five monitoring sections are set up in the opposite direction of excavation. The distance between adjacent monitoring sections is 5-10m. The near-blast zone within 15m of the blasting section is densely arranged, and the spacing is reduced to 2-5m.

[0035] Radial deployment is divided into two categories: tunnel inner wall surface monitoring and deep rock borehole monitoring. Tunnel inner wall surface monitoring: Vibration sensors are deployed at six characteristic points along the tunnel outline at the arch crown, left arch waist, right arch waist, left side wall, right side wall, and invert arch. The sensors are rigidly fixed to the tunnel structure surface and are used to monitor the vibration characteristics and structural damage response at the tunnel outline.

[0036] Deep rock borehole monitoring: Three parallel boreholes were drilled into the surrounding rock outside the tunnel outline at the left and right sidewalls of the monitoring section, with depths of 2m, 4m, and 6m respectively. A vibration sensor was installed at the bottom of each borehole, which was sealed with cement mortar to fix the sensor. This was used to monitor the vibration attenuation patterns at different depths within the surrounding rock. All monitoring points used a unified spatial coordinate system and time reference, with a sampling frequency of no less than 10kHz.

[0037] In step S2, the damage range refers to the spatial range that causes damage to the soil and tunnel structure by screening out the vibration velocity as the control target; the damage intensity refers to the degree of damage to the soil and tunnel structure at any time by outputting the vibration spectrum diagram with the vibration frequency and vibration duration as targets.

[0038] Furthermore, the damage range includes structural damage in both radial and axial dimensions; specifically, the radial dimension is the maximum damage depth from the tunnel outline into the surrounding rock (i.e., the boundary of the loosened zone of the surrounding rock caused by vibration waves); the axial dimension is the length of axial damage influence along the direction before and after tunnel excavation, centered on the previous cycle blasting section.

[0039] Furthermore, since different blasting cross sections affect the geometric effects of stress wave propagation, resulting in regional differences in the measured vibration velocity, it is necessary to divide the radial and axial damage ranges according to the data format measured under the cross section, and determine the anisotropic differences within the relative ranges.

[0040] like Figure 2 As shown, one way to realize the damage range in step S2 includes: S21, dividing the damage range in the radial and axial dimensions based on the vibration velocity and corresponding damage intensity of each monitoring point.

[0041] Damage zones are categorized by vibration velocity, including an undamaged zone (vibration velocity < 1.0 cm / s), a slightly damaged zone (vibration velocity 1.0-2.5 cm / s), a moderately damaged zone (vibration velocity 2.5-5.0 cm / s), a severely damaged zone (vibration velocity 5.0-10.0 cm / s), and a destructive zone (vibration velocity > 10.0 cm / s). Each zone represents a specific range of values, characterizing the area affected by different vibration velocities. The vibration velocities within these zones will ensure the relative stability of the corresponding rock mass or tunnel structure.

[0042] Furthermore, based on the monitoring points arranged axially and radially along the tunnel, each monitoring point is taken as a characteristic point of its spatial unit. Using the Kriging spatial interpolation method, the vibration velocity and damage intensity data of all monitoring points are spatially fitted to obtain the spatial distribution field of continuous damage characteristics. From the spatial distribution field, the spatial boundaries corresponding to different damage levels are delineated, thus completing the definition of the damage range of the area where the monitoring point is located for a single blast. At the same time, based on the vibration frequency and vibration duration data of each monitoring point, the damage intensity corresponding to each monitoring point is calculated.

[0043] S22, based on the geometry corresponding to the blasted section, calculates the ratio of the length of the damage range in different directions to the equivalent radius of the section, and uses this ratio as a spatial constraint feature of the damage range; where the equivalent radius of the section is set based on the maximum circumcircle of the corresponding area after the blasting is completed. The axial and radial lengths of the damage range are calculated by dividing the area by vibration velocity, according to the corresponding area relative to the center of the current blasted section, and the ratio of the length to the radius is used to further quantify the diffusion of the current damage range relative to the overall tunnel.

[0044] S23, based on the changes in spatial constraint features during multiple analyses, performs iterative analysis on the damage range and outputs the damage range that converges after the iterative analysis.

[0045] During multiple analysis iterations, a change of less than ±5% is considered convergence. This determines whether the current blasting scenario is convergent, outputs the convergence status, and thus obtains the output damage range.

[0046] The damage intensity in step S2 is achieved by constructing a vibration spectrum diagram corresponding to each monitoring point based on the vibration frequency and vibration duration of each monitoring point.

[0047] Frequency domain analysis is performed on the vibration spectrum to extract the dominant frequency at each monitoring point. The damage intensity is then output based on the spectral energy ratio and spectral acceleration at the dominant frequency at any given time. The dominant frequency represents the single frequency component with the most concentrated energy or the largest amplitude in the vibration spectrum, and is the dominant characteristic frequency of the vibration signal.

[0048] Specifically, frequency domain analysis converts the vibration velocity signal collected by the monitoring equipment over time into frequency domain characteristics that vary with frequency, which is used to explain issues such as resonance risk and energy distribution during the vibration process. By converting it into specific frequency domain data through Fourier transform, the energy distribution at different frequencies is characterized. Then, the frequency corresponding to the maximum value is found, which is the frequency with the highest energy proportion in the blasting vibration and the greatest contribution to the structural vibration response, and is used as the dominant vibration frequency for the current processing.

[0049] Furthermore, let the value after the Fourier transform be... The power spectral density is The corresponding principal oscillation frequency is selected by the maximum value of the power spectral density.

[0050] Furthermore, the power spectral density is calculated as follows: ;in, This represents the energy distribution at the current vibration frequency f; Indicates the duration of vibration; This section describes the amplitude and phase information at different vibration frequencies f.

[0051] Specifically, since the vibration damage of the tunnel structure itself is affected by the structure's natural frequency and structural damping, the maximum velocity response value of the tunnel structure at the monitoring point needs to be considered when determining the damage intensity caused by blasting.

[0052] Specifically, the maximum speed response value is expressed as: ;in, Indicates the input vibration velocity is At that time, the maximum velocity response value of the tunnel structure where the current monitoring point is located; It is a temporary variable used to iterate through all time points; This represents the structural damping ratio; in engineering, a value of 5% is commonly used for soil and rock masses and reinforced concrete structures. Indicates the inherent frequency of the structure; express The impulse response function at a given time is determined by the structural damping ratio and the structural natural frequency, and represents the structural response characteristics to a unit impulse vibration.

[0053] The spectral acceleration is then quantized based on this maximum response value. ;in, This represents the spectral acceleration, indicating the maximum acceleration response generated under the action of blasting vibration; Represents pi (π). The displacement response value is obtained by converting the maximum velocity response value and is expressed as follows: .

[0054] The calculation method for spectral energy is as follows: first, the vibration energy is obtained by integrating the power spectral density in the corresponding modal frequency range. The ratio of this vibration energy to the critical energy at which the structure fails is used as the output spectral energy ratio to quantify the damage intensity of the current scenario.

[0055] In one embodiment of the present invention, step S3 is used to define the spatial distribution of damage intensity. For the case of simultaneous detonation of multiple holes in the same segment, a time-series segmentation and relative spatial position processing method is adopted to divide the vibration waveform corresponding to the real-time blasting data into multiple time periods. First, the total vibration waveform monitored is segmented into time periods by utilizing the slight delay between segments. The dominant frequency, vibration duration, and other parameters of the waveform at each segment are used as the data part calculated separately for each segment. As for the single-point blasting effect, it is represented as the main attenuation direction under a single segment to characterize the energy cutting direction of each time period, which is convenient for subsequent verification of the specific blasting situation in this direction. As for multi-point superimposed blasting, it is to summarize the total blasting situation of multiple segments.

[0056] Furthermore, in subway tunnel blasting, the effective vibration duration of a single-stage blast varies according to the type of rock strata being blasted. For example, it is 5-12ms for hard rock strata and 8-20ms for soft rock / fractured surrounding rock. In this invention, the pre-set delay time is ≥25ms. When the vibration duration of a single-stage blast is less than the pre-configured delay time, the vibration waveforms of adjacent stages do not overlap. The real-time blasting data monitored can be directly segmented and windowed according to the blasting design's blasting sequence and delay time. By comparing the blasting time sequence, the damage range and damage intensity corresponding to each stage can be marked.

[0057] For scenarios such as high-charge blasting in soft / fractured surrounding rock and inter-segment delay adjustment, where the vibration duration of a single-segment initiation is greater than or equal to the preset delay time and the vibration waveforms of adjacent segments overlap, the following decoupling window correction method is adopted to achieve effective extraction and segment labeling of single-segment waveforms: First, wavelet threshold denoising preprocessing is performed on the superimposed total vibration waveform to remove environmental noise and high-frequency interference, while retaining the effective signal components of blasting vibration.

[0058] Based on the number of detonation segments, preset detonation sequence, and delay time in the blasting design, an independent component analysis (ICA) blind source separation model is constructed. Using the detonation time designed for each segment as the reference anchor point, the superimposed waveforms are decoupled and separated, and the independent vibration waveform components corresponding to each segment are extracted.

[0059] The validity of the separated single-segment waveforms is verified by calculating the vibration duration and dominant frequency of each segment and comparing them with the characteristic intervals of historical blasting data under the same conditions. A valid single-segment waveform is considered valid if the deviation of the characteristic parameters is ≤15%. If the deviation exceeds the limit, a secondary data retrieval is performed on the time window of the single-segment waveform, combining the blast source distance and wave propagation velocity, to obtain characteristic intervals similar to the scenario, until the validity requirements are met. Similar scenarios are defined by the similarity between the blast source distance and wave propagation velocity and historical blasting data, selecting characteristic intervals greater than the median value of historical similarity.

[0060] For a single waveform that has been verified to be valid, the damage range and damage intensity of each segment are marked according to the time sequence of the explosion, and the segment windowing is completed in the superimposed waveform scenario.

[0061] like Figure 3 As shown, the implementation of step S3 includes: S31, according to the delay time during blasting, segmenting and windowing the monitored real-time blasting data, and marking the damage range and damage intensity corresponding to each segment according to the blasting time sequence.

[0062] S32, for single-point blasting effect, fits the damage intensity of each monitoring point in a single segment, based on the attenuation direction of the damage intensity, aggregates the monitoring points in the attenuation direction, and selects the attenuation direction with the largest sum of damage intensity to set the single-point effect zone.

[0063] S33, for the multi-point superimposed blasting effect, calculate the proportion of the damage intensity increment of each monitoring point in the total damage intensity to form a damage contribution matrix.

[0064] S34. Select the intersection area of ​​the damage range of each segment as the main body of analysis, calculate the damage contribution matrix by superposition, and set the multi-point superposition effect area.

[0065] S35, based on the spatial location between the single-point effect area and the multi-point superimposed effect area and the monitoring point, completes the setting of the spatial mapping relationship.

[0066] Specifically, each single-point effect zone starts from the blast point and extends along the direction of damage intensity decay, forming an extended line segment. The monitoring points adjacent to this line segment are aggregated to obtain the single-point effect zone. At the same time, in order to respond to the structure of each cross section, the current extension decay direction will be represented as an extension in multiple directions. It is necessary to determine the direction with the largest damage intensity value as the output data to determine whether the current blast will be concentrated in a single direction.

[0067] Furthermore, if the main direction of a single segment does not match the preset blasting direction, the single-point effect zone represents the degree of directional deviation in shaped charge blasting. Usually, directional deviation occurs when using shaped charge tubes for blasting due to deviations in the borehole's external insertion angle, azimuth angle, or manual operation. It is necessary to check whether the surrounding rock at this location has been over-blasted, causing the part of the tunnel outline towards the interior of the surrounding rock to be mistakenly blasted.

[0068] Among them, the preset blasting direction is the direction of the free face of the slotted hole blasting or the cutting direction of the smooth blasting outline, which is preset in the blasting design document and is used to characterize the cutting direction of the blasting.

[0069] Specifically, the implementation of setting a single-point effect zone also includes: if the attenuation direction of the sum of damage intensities does not match the preset blasting direction, based on the spatial distribution of damage increments at the monitoring points, the deviation direction of the current segment is identified by polar coordinate fitting; and the deviation direction of each segment is synchronized to the single-point effect zone.

[0070] If the direction of attenuation of the sum of damage intensities is consistent with the preset blasting direction, it indicates that the actual blasting shearing direction corresponds to the designed preset blasting direction, which means that the actual blasting operation is normal, and only the blasting situation in that direction needs to be checked.

[0071] Furthermore, the implementation of setting up a multi-point superposition effect zone also includes: for monitoring points within the intersection area of ​​the damage range, calculating the similarity of the cumulative damage intensity increment of any two monitoring points according to the Pearson correlation coefficient to form multiple monitoring point pairs.

[0072] For monitoring point pairs that are spatially adjacent, the multi-point superposition effect area is set according to the calculated similarity value.

[0073] Specifically, the similarity of monitoring points within the multi-point superposition effect zone is represented as the similarity between the damage intensity change sequences of two monitoring points. It can be used as the change sequence of the cumulative damage increment of two monitoring points in the same blasting cycle as each segment of the blast source is detonated in sequence; and as the change sequence of the cumulative damage increment of two monitoring points after time alignment under different blasting conditions with adjustments to parameters such as charge amount, delay time, and energy direction.

[0074] At the same time, by labeling the detection point pairs according to similarity, it can be explained whether the two monitoring points belong to the same multi-source stress wave superposition field, that is, under the scenario of simultaneous detonation of multiple holes in the same section, they are affected by multiple post-explosion stress waves, which can explain the relative correlation under the current multi-point superposition.

[0075] Furthermore, the similarity of the cumulative damage intensity increment can be categorized into parameter values ​​of high similarity, moderate similarity, and no correlation. By selecting the median value of this similarity and the 75th percentile of historical data as the dividing numerical intervals, it is classified into three correlation values. Finally, the spatial mapping relationship is expressed as the corresponding mapping relationship between the spatial coordinates of the monitoring point and the single-point effect area and the multi-point superimposed effect area.

[0076] In one embodiment of the present invention, step S4 is used for result propagation analysis, including using regional positive and negative correlation processing for the effect partition of each blast, dividing the output distribution propagation path into propagation paths related to positive safety contribution and negative safety contribution, so as to complete the risk labeling of the path.

[0077] Specifically, such as Figure 4 As shown, the implementation of step S4 includes: S41, connecting the corresponding monitoring points based on the spatial mapping relationship of each monitoring point to form an initial propagation path; wherein, the generated initial propagation path represents the path formed by connecting the corresponding monitoring points in the single-point effect area and the multi-point superimposed effect area; the initial propagation path corresponding to the single-point effect area is the path with the largest sum of damage intensity in the attenuation direction, and the multi-point effect area indicates that there are overlapping damage ranges and similar continuous monitoring points. These monitoring points will form multiple sets of initial propagation paths according to the labeling form under the spatial mapping relationship.

[0078] S42, based on the value of each monitoring point on the initial propagation path, and using the safety threshold as the standard, when any parameter of the monitoring point is abnormal, it enters the abnormal activation state and constructs a propagation path with negative safety contribution according to the proportion exceeding the safety threshold.

[0079] S43. If any parameter of the monitoring point is normal, then enter the normal activation state and construct a propagation path for positive safety contribution according to the damage intensity of each monitoring point and the damage intensity of all monitoring points.

[0080] Among them, the safety threshold represents the parameters preset for blasting operations. The vibration waveform data corresponding to the vibration velocity, vibration frequency and vibration duration in the current scenario, the structural damage corresponding to the damage range and damage intensity, and the direction of the effect zone are used as the parameters to be checked. If any parameter is abnormal, the activation status of the corresponding monitoring point is determined by the threshold-type activation method, and the connection is made according to the corresponding activation status.

[0081] The negative safety contribution represents the proportion of each monitoring point on the current propagation path that exceeds the safety threshold, used to statistically analyze the overall degree of anomaly; the positive safety contribution, on the other hand, statistically analyzes the relative value of the damage intensity, so as to facilitate subsequent backtracking analysis of the propagation path.

[0082] Specifically, the activation state will be triggered based on whether any parameter of the vibration velocity or damage intensity at the monitoring point exceeds the safety threshold, or whether all parameters are within the safety threshold but there is cumulative damage. Correspondingly, abnormal activation state and normal activation state will be set.

[0083] Furthermore, to ensure data differentiation for each brute-force attack, it is necessary to combine the output content of the current activation state to determine the cyclical update of each activation state, thereby maintaining the dynamic update of the propagation path.

[0084] Specifically, when entering an abnormal activation state, the implementation method also includes: based on the abnormal monitoring point sequence corresponding to the current abnormal activation state, calculating the path difference between the current abnormal activation state and the previous abnormal activation state, and determining whether the path difference matches the region of the previous abnormal activation state.

[0085] If a match is found, verify the update time of the activation state and output the propagation path in order of update time.

[0086] If they do not match, the propagation path will be set according to the path difference combination method.

[0087] The path difference is calculated by using the sequence of anomaly monitoring points and the propagation path of the previous anomaly activation state as a benchmark. The path difference includes three dimensions: 1. The overlap ratio of the spatial regions corresponding to the current and previous anomaly monitoring points, and the proportion of monitoring points that are in anomaly states twice consecutively out of the total number of current anomaly monitoring points; 2. The number of newly added and disappeared anomaly monitoring points compared to the previous one; 3. The deviation of the current propagation path from the previous propagation path. These path differences represent the relative situation of the propagation path entering the anomaly activation state multiple times, and are used to explain whether the current anomaly is a continuation of the previous anomaly.

[0088] Specifically, the overlap ratio of spatial regions and the proportion of two consecutive abnormal values ​​are used as the matching basis, while the number of newly added or disappeared abnormal monitoring points and the deviation in direction are used as auxiliary marking content. Only when the overlap ratio is ≥80% and the proportion of two consecutive abnormal values ​​is ≥70%, the current path difference is considered to match the previous abnormal activation state, and it is output sequentially according to the update time. If there is no match, the propagation path of the current connection is output separately.

[0089] In one embodiment of the present invention, step S5 is used to determine the global judgment level based on the concentration of the blasting effect.

[0090] like Figure 5 As shown, the implementation of step S5 includes: S51, calling the output data of the propagation path, extracting the arrangement order of the monitoring points at each output, and counting the number of outputs for each monitoring point.

[0091] S52 sets a trend for the number of outputs based on the proportion of changes in the number of outputs at monitoring points during each blast.

[0092] S53. Based on the trend characteristics of the number of outputs, determine the judgment level of the harmful effect. The change in the number of outputs indicates whether the risk of the monitoring point, the path, or the area continues, aggravates, mitigates, or shifts during multiple rounds of blasting. On this basis, the trend characteristics of the number of outputs are represented as continuous increase, continuous decrease, long-term zero, and fluctuating changes, explaining the scenarios of risk accumulation, weakening, disappearance, and recurrence. The judgment level is synchronized with the description under the corresponding trend characteristics to characterize the persistence of the harmful effect in the current scenario, and finally form a global risk update synchronization.

[0093] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention, which are still covered within the protection scope of the present invention.

Claims

1. A method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels, characterized in that, include: S1, based on the tunnel outline, sets up monitoring points along the tunnel axis and radial direction to obtain real-time blasting data of subway tunnel blasting; Real-time blasting data includes vibration velocity, vibration frequency, and vibration duration; S2, based on the spatial location corresponding to the previous blasting section, define the damage range and damage intensity corresponding to each monitoring point during each blasting; S3. Based on the damage intensity of each monitoring point within the damage range, the damage intensity is processed according to the single-point blasting effect and the multi-point superimposed blasting effect, and a spatial mapping relationship is constructed for each monitoring point. S4. Based on the spatial mapping relationship of each monitoring point, identify the harmful effect status of each monitoring point. When the harmful effect status of a monitoring point is active, construct the propagation path between monitoring points. S5 performs coupling correlation on the data along the propagation path, and generates the judgment level of harmful effects by using the number of outputs of monitoring points within the propagation path.

2. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 1, characterized in that, The implementation methods for step S1 include: Based on the monitoring points arranged radially and axially in the tunnel, the monitoring point closest to the blasting section is selected as the initial monitoring point, and the monitoring points are gradually expanded along the axial and radial positions of the initial monitoring point to determine the number of monitoring points corresponding to the current blasting section. The number of identified monitoring points is divided according to the range of values ​​for vibration velocity, vibration frequency, and vibration duration, forming multiple sets of data corresponding to the monitoring points.

3. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 1, characterized in that, The damage extent in step S2 is achieved in the following ways: S21, based on the vibration velocity and corresponding damage intensity at each monitoring point, divide the damage range in the radial and axial dimensions; S22, based on the geometry corresponding to the blasting section, calculate the ratio of the length value of the damage range in different directions to the equivalent radius of the section, and use this ratio as the spatial constraint feature of the damage range; S23, based on the changes in spatial constraint features during multiple analyses, performs iterative analysis on the damage range and outputs the damage range that converges after the iterative analysis.

4. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 1, characterized in that, The damage intensity in step S2 is achieved through the following methods: Based on the vibration frequency and vibration duration at each monitoring point, a vibration spectrum diagram corresponding to each monitoring point is constructed. Frequency domain analysis is performed on the vibration spectrum to extract the dominant frequency of each monitoring point, and the damage intensity is output according to the spectral energy ratio and spectral acceleration at any time of the dominant frequency.

5. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 1, characterized in that, Step S3 can be implemented in the following ways: S31. Based on the delay time during blasting, the monitored real-time blasting data is segmented and windowed, and the damage range and damage intensity corresponding to each segment are marked according to the blasting time sequence. S32, for single-point blasting effect, fit the damage intensity of each monitoring point in a single segment, based on the attenuation direction of damage intensity, aggregate the monitoring points in the attenuation direction, and select the attenuation direction with the largest sum of damage intensity to set the single-point effect zone. S33, for the multi-point superimposed blasting effect, calculate the proportion of the damage intensity increment of each monitoring point in the total damage intensity to form a damage contribution matrix. S34, select the intersection area of ​​the damage range of each segment as the main body of analysis, calculate the damage contribution matrix by superposition, and set up the multi-point superposition effect area; S35, based on the spatial location between the single-point effect area and the multi-point superimposed effect area and the monitoring point, completes the setting of the spatial mapping relationship.

6. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 5, characterized in that, Other methods for setting a single-point effect zone include: If the attenuation direction of the sum of damage intensities does not match the preset blasting direction, the deviation direction of the current segment is identified by polar coordinate fitting based on the spatial distribution of damage increment at the monitoring point; and the deviation direction of each segment is synchronized to the single-point effect area.

7. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 5, characterized in that, Other methods for setting up a multi-point superposition effect zone include: For monitoring points within the intersection of damage ranges, the similarity of cumulative damage intensity increments between any two monitoring points is calculated using the Pearson correlation coefficient, forming multiple monitoring point pairs; For monitoring point pairs that are spatially adjacent, the multi-point superposition effect area is set according to the calculated similarity value.

8. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 1, characterized in that, Step S4 can be implemented in the following ways: S41, Based on the spatial mapping relationship of each monitoring point, the corresponding monitoring points are connected to form an initial propagation path; S42, for the value of each monitoring point on the initial propagation path, with the safety threshold as the standard, when any parameter of the monitoring point is abnormal, it enters the abnormal activation state and constructs a propagation path with negative safety contribution according to the proportion exceeding the safety threshold; S43. If any parameter of the monitoring point is normal, then enter the normal activation state and construct a propagation path for positive safety contribution according to the damage intensity of each monitoring point and the damage intensity of all monitoring points.

9. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 8, characterized in that, When entering an abnormal activation state, the implementation methods also include: Based on the sequence of abnormal monitoring points corresponding to the current abnormal activation state, calculate the path difference between the current abnormal activation state and the previous abnormal activation state, and determine whether the path difference matches the region of the previous abnormal activation state. If a match is found, verify the update time of the activation state and output the propagation path in order of update time. If they do not match, the propagation path will be set according to the path difference combination method.

10. The method for safety evaluation and analysis of the harmful effects of blasting in subway tunnels according to claim 1, characterized in that, Step S5 can be implemented in the following ways: S51, call the output data of the propagation path, extract the arrangement order of the monitoring points at each output, and count the number of outputs for each monitoring point; S52, set a trend for the number of outputs based on the percentage change in the number of outputs at monitoring points during each blast; S53. Determine the level of harmful effect based on the trend characteristics of the number of outputs.

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