Partitioned blasting construction analysis method for tunnel crossing cultural relic protection area

Abstract

The invention discloses a partition blasting construction analysis method for a tunnel crossing a cultural relic protection area, and relates to the technical field of blasting construction, and the method comprises the steps: building a three-dimensional geologic model and a cultural relic three-dimensional model, and constructing a finite element modal analysis environment of the blasting construction of the cultural relic protection area; the method comprises the following steps: applying a cultural relic resonance frequency in a finite element modal analysis environment of blasting construction in a cultural relic protection area, determining a limit damage threshold value of a cultural relic and a cultural relic danger node, and calculating an initial limit value of a blasting vibration safety speed according to the limit damage threshold value of the cultural relic and the cultural relic resonance frequency; calculating a cultural relic vulnerability evaluation index according to the cultural relic vulnerability influence data, and correcting the blasting vibration safety speed initial limit value to obtain a blasting vibration safety speed correction limit value; and delimiting a three-level risk area according to the cultural relic vulnerability evaluation index, and calculating and outputting the explosive quantities of the buffer area and the general construction area by using a Sadgowski formula as a vibration attenuation model. Construction vibration is ensured to be within a safety threshold, and the risk of damage to cultural relics is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of blasting construction, and specifically provides a method for analyzing partitioned blasting construction for a tunnel passing through a cultural relics protection area. Background Art

[0002] With the rapid development of infrastructure construction in China, tunnel projects are widely used in fields such as transportation and water conservancy. However, in areas with dense historical and cultural heritages, tunnel construction faces the dual challenges of cultural relics protection and engineering safety. Due to the difficulty in precisely controlling vibration, traditional blasting construction technology is extremely likely to cause irreversible damage to adjacent cultural relics. For example, in 2020, a subway tunnel construction led to cracks in a Ming Dynasty brick pagoda, exposing the limitations of traditional methods. Currently, the fixed limits in the "Safety Regulations for Blasting" (GB 6722-2014) (such as 0.5 - 1.5 cm / s) are generally adopted, but the differences in the materials, ages, and structural characteristics of cultural relics are not considered. For example, the vibration resistance of wooden buildings and masonry ruins can differ by more than 3 times, and a unified standard is likely to result in "overprotection" or "underprotection".

[0003] In the Chinese invention application with the publication number CN117670092A, a coal mine blasting data analysis system based on data analysis is disclosed, including a coal mine information acquisition module, a blastability grade analysis module, a charge filling area determination module, a coal mine blasting analysis module, a regional charge amount analysis module, a feedback terminal, and a database. By obtaining the natural parameters of each coal mine sub-region and conducting a preliminary analysis on each coal mine sub-region, the blastability grade corresponding to each coal mine sub-region is analyzed. The initial screening charge filling areas corresponding to the target coal mine are comprehensively determined, and the blasting charge amount required for the target coal mine is analyzed. Finally, the maximum load-bearing charge amount corresponding to each initial screening charge filling area is analyzed, and then the charge filling areas corresponding to the target coal mine are ultimately determined.

[0004] In the above invention application, the maximum load-bearing charge amount corresponding to each initial screening charge filling area is analyzed, but only the blastability analysis of the rock stratum is considered. In the blasting across a cultural relics protection area, if only the blastability of the rock layer is considered without considering cultural relics protection, it may cause damage or collapse of the cultural relics structure. Once the cultural relics structure is severely damaged, the repair work will become extremely complex and costly. For example, the cracks in a brick masonry structure may be accompanied by brick cracking and mortar falling off, and the repair requires professional technology and a large amount of resources. Moreover, the millennium-old historical information carried by the cultural relics may be permanently lost with the structural collapse. After the mortise and tenon joints of ancient buildings are damaged, the research materials on their construction techniques, decorative arts, etc. will be difficult to restore. After the collapse, large-scale reconstruction is required, but the original materials and techniques may have been lost. Ignoring cultural relics protection will cause multiple losses in economy, law, and society, and may also delay the project progress.

[0005] Therefore, the present invention provides a method for analyzing partitioned blasting construction for a tunnel passing through a cultural relics protection area. Summary of the Invention

[0006] (1) Technical Problem to be Solved

[0007] Aiming at the deficiencies of the prior art, the present invention provides a method for analyzing partition blasting construction for tunnel crossing a cultural relics protection area. In the finite element modal analysis environment of blasting construction in the cultural relics protection area, the resonance frequency of the cultural relics is applied, the limit damage threshold A of the cultural relics and the dangerous nodes of the cultural relics are determined. According to the limit damage threshold A of the cultural relics and the resonance frequency f of the cultural relics, the initial limit value Xz of the blasting vibration safety velocity is calculated, and according to the vulnerability influence data w of the cultural relics i the vulnerability evaluation index Cr of the cultural relics is calculated, and the initial limit value Xz of the blasting vibration safety velocity is corrected to obtain the corrected limit value Jz of the blasting vibration safety velocity. By quantifying the vulnerability of the cultural relics and the vibration response, the accurate correction of the safety threshold is realized, and all-round optimization is provided for the blasting construction, achieving a triple improvement in safety, efficiency and cost, thus solving the technical problems recorded in the background art.

[0008] (2) Technical Solution

[0009] To achieve the above object, the present invention is realized through the following technical solutions: A method for analyzing partition blasting construction for tunnel crossing a cultural relics protection area, including the following steps:

[0010] Collect the point cloud data of the geological structure and the point cloud data of the cultural relics body structure, establish a three-dimensional geological model and a three-dimensional model of the cultural relics, import the three-dimensional geological model and the three-dimensional model of the cultural relics into the same analysis environment, convert the frequency response function curve into a frequency domain excitation, apply it to the cultural relics model, and construct a finite element modal analysis environment for blasting construction in the cultural relics protection area;

[0011] In the finite element modal analysis environment of blasting construction in the cultural relics protection area, the resonance frequency of the cultural relics is applied, the limit damage threshold A of the cultural relics and the dangerous nodes of the cultural relics are determined. According to the limit damage threshold A of the cultural relics and the resonance frequency f of the cultural relics, the initial limit value Xz of the blasting vibration safety velocity is calculated, and according to the vulnerability influence data w of the cultural relics i the vulnerability evaluation index Cr of the cultural relics is calculated, and the initial limit value Xz of the blasting vibration safety velocity is corrected to obtain the corrected limit value Jz of the blasting vibration safety velocity;

[0012] According to the vulnerability evaluation index Cr of the cultural relics, three-level risk areas are delimited. For the amount of explosives in the buffer zone and the general construction area, the Sadovsky formula is used as the vibration attenuation model for calculation and output.

[0013] Furthermore, ground penetrating radar and unmanned aerial vehicle oblique photography are used to collect the point cloud data of the geological structure and the point cloud data of the cultural relics body structure, and a three-dimensional geological model and a three-dimensional model of the cultural relics are established.

[0014] Further, connect the vibrator to the insensitive part of the cultural relic through a flexible link, and arrange triaxial acceleration sensors at the key nodes of the cultural relic. The electromagnetic vibrator applies a linear sweep frequency of 0.1 - 50 Hz with a sweep rate of 1 Hz / s and an acceleration amplitude ≤ 0.05 g. After aligning the frequency data applied by the vibrator and the acceleration data collected by the acceleration sensors according to the time stamp, use the frequency data as the horizontal axis and the acceleration data as the vertical axis to plot the frequency response function curve, and identify the frequency corresponding to the peak of the curve, denoted as the resonance frequency f of the cultural relic.

[0015] Further, import the 3D geological model and the 3D model of the cultural relic into the same analysis environment, set the contact relationship between the cultural relic and the geological body (such as bonding or frictional contact), define the boundary conditions according to the geological model (such as fixed base constraint), convert the frequency response function curve into a frequency-domain excitation, apply it to the cultural relic model, and construct a finite element modal analysis environment for the blasting construction in the cultural relic protection area.

[0016] Further, in the finite element modal analysis environment for the blasting construction in the cultural relic protection area, apply the resonance frequency of the cultural relic, gradually increase the acceleration amplitude, with each level lasting 120 s. Use the elastoplastic model in ANSYS to calculate the residual strain of each node of the cultural relic through the unloading process, and sort out the number of nodes and the average residual strain exceeding the residual strain threshold at each acceleration amplitude of the cultural relic. If the number of nodes or the average residual strain exceeding the residual strain threshold exceeds the corresponding threshold, record the acceleration amplitude as the pending damage threshold of the cultural relic. After the simulation of all acceleration amplitudes is completed, take the minimum value of the pending damage threshold of the cultural relic as the ultimate damage threshold A of the cultural relic, and output the nodes exceeding the residual strain threshold of the ultimate damage threshold as the dangerous nodes of the cultural relic.

[0017] The resonance peak is the area where the energy is concentrated in the sound spectrum, reflecting the physical characteristics of the vocal tract. In the frequency response function curve, the resonance peak appears as the peak on the curve, corresponding to the natural frequency of the system, at which time the structure is easily excited.

[0018] Further, among them, the residual strain threshold is 0.005%, the threshold for the number of nodes exceeding the residual strain threshold is 1 / 3 of the total number of nodes of the cultural relic, and the threshold for the average residual strain is also 0.005%.

[0019] Further, obtain the ultimate damage threshold A of the cultural relic and the resonance frequency f of the cultural relic, and calculate the initial limit value Xz of the blasting vibration safety velocity:

[0020]

[0021] Further, obtain the data w on the vulnerability of the cultural relic such as the age of the cultural relic, the number of historical restorations, the foundation settlement amount, the building inclination angle, and the loosening ratio of the mortise and tenon structure from the historical archives of the cultural relic. i, calculate the cultural relic vulnerability evaluation index Cr:

[0022]

[0023] Among them, i represents the data number of the cultural relic vulnerability impact data, and A i represents the weight coefficient corresponding to the cultural relic vulnerability impact data with the number i, i = 1, 2,..., n, and n is the total number of cultural relic vulnerability impact data.

[0024] Furthermore, obtain the cultural relic vulnerability evaluation index Cr and the initial limit value Xz of the blasting vibration safety velocity, and calculate the corrected limit value Jz of the blasting vibration safety velocity:

[0025]

[0026] Furthermore, delimit three-level risk areas according to the cultural relic vulnerability evaluation index Cr. The core area R ≤ Cr * 30m, the buffer area Cr * �0m < R ≤ Cr * 60m, and the safety area R > Cr * 60m. Blasting is strictly prohibited in the core protection area, and a cantilever roadheader or hydraulic splitting method is used for excavation; low-intensity blasting is allowed in the buffer area, with the single-section charge ≤ 5kg, and presplitting blasting is used to form a shock-absorbing joint; in the general construction area, conventional blasting is carried out but the total charge is controlled, and the hole-by-hole initiation technology is adopted.

[0027] Furthermore, for the charges in the buffer area and the general construction area, the Sadovskii formula is used as the vibration attenuation model for calculation:

[0028] Jz = K(Q / 3R)α

[0029] Among them, Q is the maximum single-section charge, R is the minimum allowable distance from the blasting point to the cultural relic, and K and α are the site attenuation coefficients.

[0030] (III) Beneficial effects

[0031] The present invention provides a method for analyzing the sectional blasting construction for a tunnel to cross a cultural relic protection area, having the following beneficial effects:

[0032] 1. Collect the geological structure point cloud data and the cultural relic body structure point cloud data, establish a three-dimensional geological model and a three-dimensional cultural relic model, import the three-dimensional geological model and the three-dimensional cultural relic model into the same analysis environment, convert the frequency response function curve into a frequency-domain excitation, apply it to the cultural relic model, construct a finite element modal analysis environment for the blasting construction in the cultural relic protection area, and determine the structural natural frequency and vibration mode through modal analysis, providing a quantitative basis for the dynamic response of the cultural relic under blasting vibration.

[0033] 2. In the finite element modal analysis environment of blasting construction in the cultural relics protection area, apply the resonance frequency of the cultural relics to determine the ultimate damage threshold A of the cultural relics and the dangerous nodes of the cultural relics. Based on the ultimate damage threshold A of the cultural relics and the resonance frequency f of the cultural relics, calculate the initial limit value Xz of the blasting vibration safety velocity, and based on the vulnerability impact data w of the cultural relics i Calculate the vulnerability evaluation index Cr of the cultural relics, correct the initial limit value Xz of the blasting vibration safety velocity to obtain the corrected limit value Jz of the blasting vibration safety velocity. By quantifying the vulnerability of the cultural relics and the vibration response, realize the precise correction of the safety threshold, provide all-round optimization for blasting construction, and achieve a triple improvement in safety, efficiency, and cost.

[0034] 3. Delimit three-level risk areas according to the vulnerability evaluation index Cr of the cultural relics. For the amount of explosives in the buffer zone and the general construction area, use the Sadovsky formula as the vibration attenuation model to calculate and output, reasonably allocate the amount of explosives, reduce the potential impact on the cultural relics, ensure that the construction vibration is within the safety threshold, and reduce the risk of damage to the cultural relics. Brief Description of the Drawings

[0035] Figure 1 It is a schematic flow chart of a zoning blasting construction analysis method for a tunnel passing through a cultural relics protection area according to the present invention. Detailed Embodiments

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] Please refer to Figure 1 , the present invention provides a zoning blasting construction analysis method for a tunnel passing through a cultural relics protection area, including the following steps:

[0038] Step 1. Collect the geological structure point cloud data and the cultural relics body structure point cloud data, establish a three-dimensional geological model and a three-dimensional cultural relics model, import the three-dimensional geological model and the three-dimensional cultural relics model into the same analysis environment, convert the frequency response function curve into a frequency domain excitation, apply it to the cultural relics model, and construct a finite element modal analysis environment for blasting construction in the cultural relics protection area.

[0039] The said Step 1 includes the following contents:

[0040] Step 101. Use ground penetrating radar and UAV oblique photography to collect the geological structure point cloud data and the cultural relics body structure point cloud data, and establish a three-dimensional geological model and a three-dimensional cultural relics model.

[0041] Step 102: Connect the vibrator to the insensitive part of the cultural relic (such as the base) through a flexible connecting rod, and arrange triaxial acceleration sensors at the key nodes of the cultural relic (such as the eaves corner and column base). The electromagnetic vibrator applies a linear sweep from 0.1 to 50 Hz with a sweep rate of 1 Hz / s and an acceleration amplitude ≤ 0.05g. After aligning the frequency data applied by the vibrator and the acceleration data collected by the acceleration sensors according to the time stamp, use the frequency data as the horizontal axis and the acceleration data as the vertical axis to plot the frequency response function curve, and identify the frequency corresponding to the peak of the curve, which is denoted as the resonance frequency f of the cultural relic.

[0042] The resonance peak is the area where the energy is concentrated in the sound spectrum, reflecting the physical characteristics of the vocal tract. In the frequency response function curve, the resonance peak appears as the peak on the curve, corresponding to the natural frequency of the system. At this time, the structure is easily excited.

[0043] Step 103: Import the three-dimensional geological model and the three-dimensional model of the cultural relic into the same analysis environment, set the contact relationship between the cultural relic and the geological body (such as bonding or frictional contact), define the boundary conditions according to the geological model (such as fixed constraint at the base), convert the frequency response function curve into a frequency-domain excitation, apply it to the cultural relic model, and construct a finite element modal analysis environment for the blasting construction in the cultural relic protection area.

[0044] During use, combine the content in Steps 101 to 103:

[0045] Collect the point cloud data of the geological structure and the point cloud data of the cultural relic body structure, establish a three-dimensional geological model and a three-dimensional model of the cultural relic, import the three-dimensional geological model and the three-dimensional model of the cultural relic into the same analysis environment, convert the frequency response function curve into a frequency-domain excitation, apply it to the cultural relic model, construct a finite element modal analysis environment for the blasting construction in the cultural relic protection area, and determine the natural frequency and vibration mode of the structure through modal analysis to provide a quantitative basis for the dynamic response of the cultural relic under blasting vibration.

[0046] Step Two: Under the finite element modal analysis environment for the blasting construction in the cultural relic protection area, apply the resonance frequency of the cultural relic to determine the ultimate damage threshold A of the cultural relic and the dangerous nodes of the cultural relic. Based on the ultimate damage threshold A of the cultural relic and the resonance frequency f of the cultural relic, calculate the initial limit value Xz of the blasting vibration safety velocity, and based on the vulnerability impact data w of the cultural relic i Calculate the vulnerability evaluation index Cr of the cultural relic, and correct the initial limit value Xz of the blasting vibration safety velocity to obtain the corrected limit value Jz of the blasting vibration safety velocity.

[0047] The above Step Two includes the following content:

[0048] Step 201: In the finite element modal analysis environment of blasting construction in the cultural relics protection area, apply the resonance frequency of the cultural relics, gradually increase the acceleration amplitude (0.1g → 0.2g → 0.3g…), each level lasts for 120 s. Use the elastoplastic model in ANSYS, calculate the residual strain of each node of the cultural relics through the unloading process, sort out the number of nodes exceeding the residual strain threshold and the average residual strain of the cultural relics at each acceleration amplitude. If the number of nodes exceeding the residual strain threshold or the average residual strain exceeds the corresponding threshold, record this acceleration amplitude as the pending damage threshold of the cultural relics. After the simulation of all acceleration amplitudes is completed, take the minimum value of the pending damage threshold of the cultural relics as the ultimate damage threshold A of this cultural relic, and output the nodes exceeding the residual strain threshold of this ultimate damage threshold as the dangerous nodes of the cultural relics.

[0049] Among them, the residual strain threshold is 0.005%, the threshold of the number of nodes exceeding the residual strain threshold is 1 / 3 of the total number of all nodes of the cultural relics, and the threshold of the average residual strain is also 0.005%.

[0050] Step 202: Obtain the ultimate damage threshold A of the cultural relics and the resonance frequency f of the cultural relics, and calculate the initial limit value Xz of the blasting vibration safety velocity:

[0051]

[0052] Step 203: Obtain the cultural relics vulnerability impact data w such as the age of the cultural relics, the number of historical restorations, the foundation settlement amount, the building inclination angle, and the loosening ratio of the mortise and tenon structure from the historical archives of the cultural relics i , and calculate the cultural relics vulnerability evaluation index Cr:

[0053]

[0054] Among them, i represents the data number of the cultural relics vulnerability impact data, A i represents the weight coefficient corresponding to the cultural relics vulnerability impact data numbered i, i = 1, 2, …, n, and n is the total number of the cultural relics vulnerability impact data.

[0055] Step 204: Obtain the cultural relics vulnerability evaluation index Cr and the initial limit value Xz of the blasting vibration safety velocity, and calculate the corrected limit value Jz of the blasting vibration safety velocity:

[0056]

[0057] When in use, combine the content in Steps 201 to 204:

[0058] In the finite element modal analysis environment of blasting construction in the cultural relics protection area, apply the resonance frequency of the cultural relics, determine the ultimate damage threshold A of the cultural relics and the dangerous nodes of the cultural relics. Based on the ultimate damage threshold A of the cultural relics and the resonance frequency f of the cultural relics, calculate the initial limit value Xz of the blasting vibration safety velocity, and based on the vulnerability impact data w of the cultural relics i Calculate the cultural relics vulnerability evaluation index Cr, correct the initial limit value Xz of the blasting vibration safety velocity to obtain the corrected limit value Jz of the blasting vibration safety velocity. By quantifying the vulnerability of the cultural relics and the vibration response, achieve the precise correction of the safety threshold, provide all-round optimization for the blasting construction, and achieve a triple improvement in safety, efficiency, and cost.

[0059] Step 3: Delimit three-level risk areas according to the cultural relics vulnerability evaluation index Cr. For the explosive charges in the buffer zone and the general construction area, use the Sadovsky formula as the vibration attenuation model for calculation and output.

[0060] The said Step 3 includes the following contents:

[0061] Step 301: Delimit three-level risk areas according to the cultural relics vulnerability evaluation index Cr, the core area (R ≤ Cr * 30m), the buffer zone (Cr * 30m < R ≤ Cr * 60m), the safety area (R > Cr * 60m). Blasting is strictly prohibited in the core protection area, and use a cantilever roadheader or hydraulic splitting method for excavation. Low-intensity blasting is allowed in the buffer zone, with the single-section explosive charge ≤ 5kg, and pre-splitting blasting is used to form a shock-absorbing joint. Conventional blasting is carried out in the general construction area but the total explosive charge is controlled, and the hole-by-hole initiation technology is adopted.

[0062] Step 302: For the explosive charges in the buffer zone and the general construction area, use the Sadovsky formula as the vibration attenuation model for calculation:

[0063] Jz = K(Q / 3R)α

[0064] Wherein, Q is the maximum single-section explosive charge, R is the minimum allowable distance from the blasting point to the cultural relics, and K and α are the site attenuation coefficients, which are calibrated through on-site tests.

[0065] When in use, combine the contents in Steps 301 and 302:

[0066] Delimit three-level risk areas according to the cultural relics vulnerability evaluation index Cr. For the explosive charges in the buffer zone and the general construction area, use the Sadovsky formula as the vibration attenuation model for calculation and output, reasonably distribute the explosive charges, reduce the potential impact on the cultural relics, ensure that the construction vibration is within the safety threshold, and reduce the risk of damage to the cultural relics.

[0067] The present invention provides another embodiment of the method for quantifying the vulnerability impact data of cultural relics:

[0068] The age limit (A1) is classified by era: Ming and Qing dynasties (300 - 600 years) 1 point, Song and Yuan dynasties (600 - 1000 years) 2 points, Tang dynasty and before (> 1000 years) 3 points

[0069] For each additional restoration in the number of historical restorations (A2), the score is increased by 0.5 points (with a ceiling of 3 points)

[0070] For the foundation settlement amount (A3), the differential settlement rate (mm / year) ≤ 0.5, 0 points; 0.5 - 1.0, 1 point; > 1.0, 2 points

[0071] For the building inclination angle (A4), the inclination rate (‰) ≤ 1.0, 0 points; 1.0 - 3.0, 1 point; > 3.0, 2 points

[0072] For the proportion of loose mortise and tenon joints (A5), the proportion of loose joints ≤ 10%, 0 points; 10 - 30%, 1 point; > 30%, 2 points

[0073] The present invention provides another embodiment of the method for allocating index weights of cultural relic vulnerability impact data:

[0074] The analytic hierarchy process (AHP) is used to determine the weights. A judgment matrix is constructed through expert scoring, and the consistency ratio (CR < 0.1) is calculated:

[0075]

[0076] The present invention provides another embodiment of the method for calculating the cultural relic vulnerability index:

[0077] Evaluation data of a certain wooden pagoda in the Qing Dynasty: Age limit: 200 years (1 point), number of restorations: 3 times (1.5 points), settlement amount: 0.8 mm / year (1 point), inclination angle: 2.5‰ (1 point), loose mortise and tenon joints: 15% (1 point):

[0078] Calculation process:

[0079] Cr = 0.32×1 + 0.42×1.5 + 0.15×1 + 0.08×1 + 0.03×1 = 1.18

[0080] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution.

[0081] The unit described as a separation component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or may be distributed over multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0082] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application.

Claims

1. A method for analyzing the construction of sectional blasting for tunnel crossing cultural relic protection areas, characterized in that: It includes the following steps: Collect the point cloud data of the geological structure and the point cloud data of the cultural relics' main body structure, establish a three-dimensional geological model and a three-dimensional model of the cultural relics, import the three-dimensional geological model and the three-dimensional model of the cultural relics into the same analysis environment, convert the frequency response function curve into a frequency-domain excitation, apply it to the cultural relics model, and construct a finite element modal analysis environment for blasting construction in the cultural relics protection area; Under the finite element modal analysis environment of blasting construction in the cultural relics protection area, apply the resonance frequency of the cultural relics to determine the ultimate damage threshold A of the cultural relics and the dangerous nodes of the cultural relics. According to the ultimate damage threshold A of the cultural relics and the resonance frequency f of the cultural relics, calculate the initial limit value Xz of the blasting vibration safety velocity, and based on the vulnerability impact data w of the cultural relics i Calculate the vulnerability evaluation index Cr of the cultural relics, and correct the initial limit value Xz of the blasting vibration safety velocity to obtain the corrected limit value Jz of the blasting vibration safety velocity; Define three-level risk areas according to the cultural relics vulnerability evaluation index Cr, and use the Sadovsky formula as the vibration attenuation model to calculate and output the explosive charges for the buffer zone and the general construction area.

2. A method for analyzing sectional blasting construction for tunnel crossing a cultural relics protection area according to claim 1, characterized in that: Connect the exciter to the non-sensitive part of the cultural relics through a flexible connecting rod, and arrange triaxial acceleration sensors at the key nodes of the cultural relics. The electromagnetic exciter applies a linear sweep frequency of 0.1 - 50 Hz with a sweep rate of 1 Hz / s and an acceleration amplitude ≤ 0.05 g. After aligning the frequency data applied by the exciter and the acceleration data collected by the acceleration sensors according to the time stamp, use the frequency data as the horizontal axis and the acceleration data as the vertical axis to plot the frequency response function curve, and identify the frequency corresponding to the peak of the curve, denoted as the resonance frequency f of the cultural relics.

3. A method for analyzing sectional blasting construction for tunnel crossing a cultural relics protection area according to claim 1, characterized in that: Under the finite element modal analysis environment of blasting construction in the cultural relics protection area, apply the resonance frequency of the cultural relics, gradually increase the acceleration amplitude, with each level lasting 120 s. Use the elastoplastic model in ANSYS to calculate the residual strain of each node of the cultural relics through the unloading process, and sort out the number of nodes and the average residual strain exceeding the residual strain threshold at each acceleration amplitude of the cultural relics. If the number of nodes or the average residual strain exceeding the residual strain threshold exceeds the corresponding threshold, record this acceleration amplitude as the undetermined damage threshold of the cultural relics. After all acceleration amplitude simulation simulations are completed, take the minimum value of the undetermined damage threshold of the cultural relics as the ultimate damage threshold A of the cultural relics, and output the nodes exceeding the residual strain threshold of this ultimate damage threshold as the dangerous nodes of the cultural relics.

4. A method for analyzing sectional blasting construction for tunnel crossing a cultural relics protection area according to claim 1, characterized in that: Among them, The residual strain threshold is 0.005%, the threshold for the number of nodes exceeding the residual strain threshold is 1 / 3 of the total number of nodes of the cultural relics, and the threshold for the average residual strain is also 0.005%.

5. A method for analyzing sectional blasting construction for tunnel crossing a cultural relics protection area according to claim 1, characterized in that: Obtain the ultimate damage threshold A of the cultural relics and the resonance frequency f of the cultural relics, and calculate the initial limit value Xz of the blasting vibration safety velocity:

6. A method for analyzing sectional blasting construction for tunnel crossing a cultural relics protection area according to claim 1, characterized in that: Obtain data on the impact of cultural relic vulnerability such as the age of cultural relics, the number of historical restorations, the foundation settlement, the building inclination angle, and the loosening ratio of mortise and tenon structures from the historical archives of cultural relics w i , and calculate the cultural relic vulnerability evaluation index Cr: Among them, i represents the data number of the data on the impact of cultural relic vulnerability, A i represents the weight coefficient corresponding to the data on the impact of cultural relic vulnerability with the number i, where i = 1, 2, …, n, and n is the total number of data on the impact of cultural relic vulnerability.

7. A method for analyzing sectional blasting construction for tunnel crossing a cultural relics protection area according to claim 1, characterized in that: Obtain the cultural relics vulnerability evaluation index Cr and the initial limit value Xz of the blasting vibration safety velocity, and calculate the corrected limit value Jz of the blasting vibration safety velocity: 。 8. A method for analyzing sectional blasting construction for a tunnel passing through a cultural relics protection area according to claim 1, characterized in that: Three-level risk areas are delimited based on the cultural relic vulnerability evaluation index Cr, with the core area R ≤ Cr * 30m, the buffer area Cr * 30m < R ≤ Cr * 60m, and the safety area R > Cr * 60m. Blasting is strictly prohibited in the core protection area, and excavation is carried out using a cantilever roadheader or hydraulic splitting method; low-intensity blasting is allowed in the buffer area, with the single-section charge ≤ 5 kg, and presplitting blasting is used to form a shock-absorbing joint; in the general construction area, conventional blasting is carried out but the total charge is controlled, and the hole-by-hole initiation technology is adopted.

9. A method for analyzing sectional blasting construction for a tunnel passing through a cultural relics protection area according to claim 1, characterized in that: For the charges in the buffer area and the general construction area, the Sadovsky formula is used as the vibration attenuation model for calculation: Jz = K(Q / 3R)α Where Q is the maximum single-section charge, R is the minimum allowable distance from the blasting point to the cultural relic, and K and α are the site attenuation coefficients.

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