Research on the Impact of Blasting Vibration in Mining Areas on Surrounding Railway Structures

Abstract

To study the safety impact of open-pit blasting on railway structures, blasting vibration tests were conducted on the railway. Numerical simulation methods were employed to establish a three-dimensional finite element model of the railway structure, encompassing the rail, sleepers, and subgrade. By applying the measured blasting vibration waves from the railway platform and amplifying their velocities to various multiples, the variation patterns of the vibration velocity and displacement of the railway structure were calculated and analyzed. The research findings suggest that the rail in the railway structure is less affected by the vibration, whereas the sleepers and subgrade are more significantly influenced by the blasting vibration. The peak velocities and displacements generated by the structure are well below the requirements of the relevant regulations. Upon amplifying the loading velocities to different multiples and conducting the analysis, it was observed that as the vibration velocity increases, the velocity and displacement of the structure increase to varying extents. It is recommended to control the blasting vibration velocity below 3 cm/s and to adopt corresponding security technology measures.

1. Introduction

Railways are an integral part of the land transportation network, playing a pivotal role in economic growth and national security, and are essential for societal advancement [1]. Blasting is a prevalent technique in open-pit mining, where detonations release substantial energy, some of which travels as vibration waves through the surrounding environment. These vibration waves, upon reaching the railway subgrade, can induce tremors in the railway infrastructure, thus impacting its safety [2,3,4]. With the expansion of mining operations, the scale of which is growing, mining depths are gradually increasing, and the boundaries of mining zones are extending, and the proximity to nearby railways diminishes. The vibrations from daily blasting activities could affect the surrounding railway structures, potentially causing damage or even jeopardizing public safety [5]. Consequently, it is imperative to analyze the structural safety of railways adjacent to mines when subjected to vibrations from blasting.

The purpose of this research is to investigate the dynamic response of railway structures to blasting vibrations and to establish safe operational limits for blasting activities. By combining on-site vibration testing with numerical simulations, this study aims to provide a comprehensive understanding of how blasting vibrations propagate through railway structures and affect their integrity. The findings of this research are significant for both engineering practice and policy-making, as they contribute to the development of safer blasting protocols and help minimize the risk of structural damage to railway infrastructure.

Currently, scholars have employed various methods to study the impact of vibrations on railway structures, primarily focusing on theoretical research, numerical simulation, and field testing, achieving certain results. Some scholars have studied the deformation effects of train-induced vibrations on railway tracks and subgrades, proposed different analysis models, simulated train loading during passage, established a train vibration source function, simulated vibration waves from high-speed trains, and investigated track vibrations under different load conditions [6,7,8,9]. Fattah et al. [10] investigated the effects of railway track vibrations on saturated and unsaturated subgrade layers through laboratory models and cyclic loading experiments, examining the influence of varying saturation levels and load frequencies on subgrade stresses and deformations, and providing recommendations for track design optimization. Pierre et al. [11] introduced a novel method combining a device for measuring deformation at multiple depths with a satellite-based system for precise positioning. This approach enhances the accuracy of track settlement monitoring by integrating absolute displacement data from the satellite system with relative deformation measurements from the multi-depth measurement device. Qu et al. [12] investigated the subgrade vibrations and long-term stability of an embankment-bridge transition zone in a non-ballasted high-speed railway. They conducted two field tests 32 months apart, analyzed FFT, and calculated dynamic shear strains to evaluate stability. Results showed that the abutment’s influence diminishes with distance, leading to increased vibration amplitudes and lower dominant frequencies. The subgrade’s dynamic stability remained within acceptable limits after 32 months of operation. This study provides insights for designing and maintaining high-speed railway transition zones. Their study provides insights into the impact of blasting vibrations on railway structures.

Monitoring the displacement and velocity responses of railway structures to vibrations in the field is challenging. As an effective research method, numerical simulation has been widely applied. Park et al. [13] analyzed the dynamic characteristics of high-speed trains passing through transition zones using finite element models and on-site measurement data, validating the accuracy of numerical models and exploring the influence of train speed on track stresses and wheel-rail interactions. Khajehdezfuly et al. [14] used a vehicle/track interaction model to obtain force-time history curves for road and railway vehicles, which were then input into a 3D finite element model to analyze the influence of different parameters on vibration caused by vehicles. Jiang et al. [15] proposed a differential evolution algorithm based on 3DEC dynamic analysis, establishing a 3DEC model for the complex ore body of an eastern sulfur iron mine. By analyzing field-monitored vibration displacement and velocity data, waveforms and parameters were simulated, revealing that when the safety vibration velocity of the railway was 4.5 cm/s, the maximum allowable single explosive charge in the area was 44.978 kg.

However, most studies focus only on specific structures or aspects, with limited research on the impact of blasting vibrations on the overall railway structure. This paper focuses on a railway located near a mine site, analyzing vibration response signals from blasting-induced vibrations through monitoring data and field surveys. The signals were pre-processed and analyzed in the frequency domain, then incorporated into a 3D finite element model of the entire railway structure, including the steel rails, rail ties, and subgrade. This study discusses key parameters such as displacement and vibration velocity caused by blasting-induced vibrations, comparing and analyzing the vibration deformation and safety impact on the railway structure.

2. Methods

To investigate the impact of blasting vibrations on railway structures, this study employed a systematic approach combining on-site vibration testing and numerical simulation. The methodology is outlined as follows:

(1)

Install vibration testing instruments during normal railway operations to record the vibration data of the railway tracks as trains pass, as well as the vibration response of the surrounding environment.

(2)

Building a 3-D model of the railway structure based on collected parameters, meshing the model, applying boundary constraints, and considering actual material properties.

(3)

Conduct modal analysis on the 3-D model to determine the resonance frequency range.

(4)

Integrate the actual vibration data from on-site testing into the 3-D finite element model. Subsequently, perform additional analysis and calculations, considering material and geometric nonlinearity, to simulate the stress, strain, and displacement responses of the railway structure. Using the results and relevant safety standards, assess the safety of the railway structure under various vibration conditions and establish the safe vibration speed threshold.

3. Project Overview and Blasting Vibration Testing

3.1. Overview of the Mine and Surrounding Environment

The mine is situated in the southwest of Haikou Town, Xishan District, Kunming City, on the western side of Dianchi Lake. It is part of a low-to-mid-mountain terrain. The highest point is at Shansongyuan in the western section of the site, reaching an elevation of 2482 m, whereas the lowest point is at the northwest edge of the surveyed area, in the Mingyi River Valley, with an elevation of about 1860 m. The maximum elevation variation is 622 m, with elevations generally ranging from 2100 to 2250 m and a typical elevation difference between 240 and 390 m. The rock in the blasting area is predominantly dolomitic sandstone, featuring relatively stable structural conditions and no observed fault zones. Its geographical location is distinctive, being adjacent to Dianchi Lake, and it possesses abundant groundwater resources.

The primary protection targets in the vicinity of the mine are the residential buildings in Haifeng Village and Ercai Village, as well as the adjacent railway. The railway is a standard Chinese railway with a track gauge of 1.435 m. The ties are constructed from reinforced concrete, measuring 220 mm in width, 160 mm in thickness, and 2500 mm in length. The total depth of the subgrade is 2.3 m, utilizing layered fill materials. Blasting operations near the railway employ No. 1 rock emulsion explosives, with a total of 110 blast holes arranged in five rows. The holes are spaced 6 m apart, and the rows are spaced 5 m apart. The total quantity of explosives used amounts to 9792 kg, with a maximum charge per section not exceeding 90 kg. Digital electronic detonators are used for delayed blasting, with a delay interval of 45 ms between holes, and the explosive consumption rate is 0.32 kg per cubic meter.

As the mining area continues to expand and mining depths gradually increase, the boundaries of the mining area also gradually extend, bringing it closer to the surrounding Kunyang branch line railway. The blasting vibrations from the mine’s daily production may affect the structural safety of the surrounding railway and residential buildings. Should the railway structure experience displacement or deformation, it could result in significant losses for the enterprise and endanger the safety of people’s lives and property. Consequently, it is essential to analyze the structural safety of the Kunyang branch line railway and residential buildings near the mine, considering the effects of daily production blasting vibrations.

3.2. Blasting Vibration Testing

The precision of the testing instruments is closely related to the outcomes of the blasting vibration tests. The on-site blasting vibration monitoring experiment utilizes the TC-4850 blasting vibration meter in conjunction with three-direction vibration velocity sensors that are compatible with the meter. The blasting vibration testing system is depicted in Figure 1. The system comprises several key components as follows: a velocity sensor positioned at the measurement point with its x-axis aligned toward the blast area, a vibration meter connected to the sensor for signal acquisition, a data acquisition unit for converting the signal into a digital format, and a computer for data processing and analysis. The sensor’s y-axis is oriented perpendicular to the x-axis in the horizontal plane, and the z-axis is vertical, ensuring comprehensive measurement of vibrations in three orthogonal directions. The data collected on-site were imported into a computer for processing, enabling the acquisition of the raw blasting vibration waveform data.

The surrounding area of the mining site consists of water-rich rock layers, and the propagation of blasting vibrations is influenced by various factors, including the maximum charge per delay, distance from the blast center, site conditions, and the propagation medium. To more effectively monitor railway vibrations around the mining area, multiple measurement points were arranged in a straight line as much as possible between the railway platform measurement points. Each measurement point is labeled as 1, 2, 3, and 4, as shown in Figure 1. At each measurement point, a three-direction velocity sensor was fixed using gypsum at the subgrade or bedrock to monitor the vibration velocity in three directions. The equipment trigger value was set at 0.015 cm/s, with a 10-s recording duration and a 16 kHz sampling rate. The sensor’s x-axis was aligned toward the blast area, with the positive direction pointing from the measurement point toward the epicenter of the explosion. The y-axis was oriented perpendicular to the x-axis in the horizontal plane, and the z-axis was oriented vertically, perpendicular to both the x-axis and y-axis. The velocity sensor converted the blasting vibration signal into an electrical signal, which was transmitted to the vibration meter for real-time processing. To establish the time correlation between the measurement and the explosion, the vibration duration was defined as the time from the arrival of the blast wave to the decay of the signal amplitude to 1/e of its maximum value. The trigger value ensured immediate recording upon detecting the initial blast wave, capturing the full time history of the vibration. For multi-hole blasting, delay intervals were optimized to minimize overlapping vibration effects, and the time delay between blast initiation and signal arrival at the sensor was accounted for based on the distance from the blast source to the sensor and wave propagation speed. After processing the on-site test data, the raw data and waveforms of the blasting vibration were obtained, providing a basis for further analysis and evaluation of the vibration impact on nearby structures.

The peak vibration velocity in each direction for different measurement points is shown in

Table 1. Monitoring results of measurement points.

Measurement Point	Direction	Maximum/(cm·s−1)	Main Frequency/Hz	Distance/m
1	X	0.169	12.32	688
	Y	0.167	14.49
	Z	0.098	9.61
2	X	0.119	17.55	725
	Y	0.136	19.95
	Z	0.043	6.38
3	X	0.035	18.99	787
	Y	0.036	6.83
	Z	0.033	15.70
4	X	0.050	17.21	877
	Y	0.051	6.62
	Z	0.073	36.20

. A comparative analysis of the data collected from four railway measurement points revealed that Measurement Point 1, being closer to the blast area, had a larger peak vibration velocity compared to the other measurement points. Therefore, the data from Measurement Point 1 was used for further analysis.

3.3. Vibration Data Processing

The impact of blast vibrations on structures is closely related to the peak velocity and frequency. The FFT filtering method is used to filter the raw waveform data [16]. By performing a Fourier transform, the time-domain data are converted into the frequency domain. The low-pass filter eliminates unnecessary data and high-frequency anomalies, reducing the influence of noise and interference on the blast vibrations. This results in waveform data in the x, y, and z directions, as shown in Figure 2. The processed data are then imported into the railway finite element model for further analysis and computation.

4. Simulation Analysis

4.1. Dynamic Response Time History Analysis Method

The vibration differential equation for a multi-degree-of-freedom elastic system under vibration [17] (see Equation (1)):

$$\left[\mathrm{M}\right]\left\{\ddot{\mathrm{x}}\right\}+\left[\mathrm{c}\right]\left\{\dot{\mathrm{x}}\right\}+\left[\mathrm{K}\right]\left\{\dot{\mathrm{x}}\right\}=\left[\mathrm{M}\right]\left\{{\ddot{\mathrm{x}}}_{\mathrm{g}}\right\}$$

(1)

where $\left[\mathrm{M}\right]$ represents the mass matrix, in kilograms (kg); $\left[\mathrm{c}\right]$ is the damping matrix, in kilograms per second (kg/s); $\left[\mathrm{K}\right]$ denotes the damping matrix, in Newtons per meter (N/m); $\left\{\ddot{\mathrm{x}}\right\}$ is the system’s relative horizontal acceleration vector, in meters per second squared (m/s²); $\left\{\dot{\mathrm{x}}\right\}$ represents the system’s relative horizontal velocity vector, in meters per second (m/s); $\left\{\dot{\mathrm{x}}\right\}$ is the system’s relative horizontal displacement vector, in meters (m); and $\left\{{\ddot{\mathrm{x}}}_{\mathrm{g}}\right\}$ denotes the ground horizontal acceleration vector, in meters per second squared (m/s²).

The time history analysis method involves solving equations through numerical integration over several continuous time intervals, based on the structural restoring force characteristic curve. By inputting vibration waveform data and employing numerical computation methods from structural dynamics and finite element analysis, the system performs incremental integration from the initial state to calculate the velocity, acceleration, and displacement dynamic responses of each mass point as they evolve over time.

The dynamic response of the structure is significantly affected by damping, with the effect of the damping ratio being inversely proportional to the displacement response. Rayleigh damping [18] is selected as follows (see Equation (2)):

$$\mathrm{C}=\alpha \mathrm{M}+\beta \mathrm{K}\hspace{0.25em}$$

(2)

where $\mathrm{C}$ represents the damping matrix in the dynamic equation, measured in kg/s; α is the mass-proportional damping constant, measured in 1/s; β is the stiffness-proportional damping; M is the mass matrix, measured in kg; K is the stiffness matrix, measured in N/m; and αM denotes the mass component; and βK signifies the stiffness component.

4.2. Railway Model Establishment

Using SolidWorks for 3D modeling and HyperMesh for meshing, the steel rails, railroad ties, and subgrade in the vicinity of the mining area have been modeled and meticulously meshed. The dimensions of the model are consistent with the actual site conditions, as depicted in Figure 3. The rail spacing measures 1435 m, the railroad ties have dimensions of 220 mm in width, 160 mm in thickness, and 2500 mm in length, and the total thickness of the subgrade is 2.3 m. The meshes of various structures are connected by shared nodes, and the overall model consists of 333,292 elements and 385,637 nodes.

To simplify the analysis, the steel rails, railroad ties, and subgrade are each calculated using three different materials. The specific parameters are shown in

Table 2. Parameters of railway structural materials.

Material	Density/(kg·m−3)	Elastic Modulus/Pa	Poisson’s Ratio	Damping Ratio
Rail	7830	2.06 × 1011	0.3	0.05
Sleeper	2500	2.82 × 1010	0.2	0.08
Subgrade	2130	2.53 × 107	0.28	1

.

Linear elastic behavior was assumed with considerations for nonlinearity. Fixed boundary conditions were applied at the bottom nodes to prevent displacement/rotation, along with non-reflective boundaries to minimize wave reflections.

After adding the corresponding keywords, the ANSYS/LSDYNA software version R11 is used for analysis and computation.

4.3. Analysis and Calculation

Considering the actual situation, when analyzing and calculating the railway model, the impact of the self-weight of the railway structure itself must be taken into account. Initially, the self-weight stress calculation for the railway should be performed, as depicted in Figure 4. The simulation of the railway structure should adhere to the self-weight distribution law, which can provide initial conditions for the subsequent vibration calculations.

The vibration waves generated by blasting are transmitted to the railway structure through the ground. The bottom nodes of the model are selected, and after performing the self-weight calculation, the time history curves of the horizontal radial, horizontal tangential, and vertical velocities are imported and applied to the calculation, respectively.

4.3.1. Modal Analysis

When studying the dynamic response of railway structures to blasting vibration waves, it is essential to consider the influence of their inherent characteristics, such as mass and the distribution of elastic properties. These characteristics are manifested through natural frequencies and mode shapes (Yang et al. [19]).

ANSYS is utilized to conduct a modal analysis on the railway structure, calculating its natural frequencies and mode shapes. The results for the initial six modes are presented in

Table 3. Results of modal analysis of the first 6 orders of railway structure.

Mode	1st	2nd	3rd	4th	5th	6th
Frequency/Hz	3.106	6.317	6.796	7.437	7.557	8.809

. Each mode represents a unique vibration pattern at a specific frequency. Here, “6 orders” refers to the first six vibration patterns, ranked from the lowest to the sixth frequency.

For a given structure, the frequency at which resonance occurs is commonly known as the first-order natural frequency [20]. In this instance, the resonance frequency of the railway structure is 3.106 Hz. The closer the frequency of the vibration waves produced by an explosion is to the resonance frequency, the greater the impact on the structure.

4.3.2. Structural Velocity Response Analysis

Based on the simulation results, the velocity response of the railway structure is analyzed at the moments corresponding to the maximum velocity in the three directions from the blasting vibration test data. By comparing the velocity distribution contour maps at different moments, as shown in Figure 5, it can be observed that the steel rails of the railway structure are least affected by the vibration, while the rail ties and subgrade experience a greater impact from the vibration. When affected by the horizontal radial direction, the vibration response of the structure is more pronounced.

To accurately analyze the specific velocities and variation patterns of the structure affected by blasting vibrations, velocity–time history curves under the influence of different directional vibrations are extracted for the subgrade, rail ties, and steel rails, respectively.

Figure 6a–c represent the velocity–time history curves in three directions under the influence of blasting vibrations. It is observed that the velocity–time history curves of the railway structure in all three directions generally align with the waveforms of the vibration curves produced by the blasting. In the x-direction velocity response curve of the structure, the velocity response value is highest at the rail ties, followed by the subgrade, and lowest at the steel rails. The peak value occurs at 1.65 s at the rail ties, with a value of 0.54 cm/s. In the y-direction and z-direction velocity response curves of the structure, the velocity response value is highest at the subgrade, followed by the rail ties, and lowest at the steel rails. The peak values in the y-direction and z-direction occur at 2.75 s (0.35 cm/s) and 1.95 s (0.51 cm/s), respectively. This indicates a directional variation in the subgrade response, with the y-direction exhibiting a later peak compared to the z-direction. The peak vibration velocities in each direction are all significantly lower than the blasting vibration safety limits specified in TB10313-2019 “Technical Regulations for Railway Engineering Blasting Vibration Safety [21]” (see

Table 4. Safety allowable values for blasting vibration of railway subgrade.

Category	Particle Vibration Velocity Safety Limit V/(cm·s−1)
	f ≤ 10 Hz	10 Hz < f ≤ 50 Hz	f > 50 Hz
Ballasted track subgrade	5~6	6~7	7~8
Unballasted track subgrade	3~4	4~5	5~6

).

Upon comparing the three directional velocity response curves, it becomes evident that the x-direction velocity response value exceeds those in the other directions. This is attributed to the larger peak horizontal radial velocity produced by the blasting, coupled with a smaller main frequency in comparison to the y-direction. Although the peak velocity in the vertical direction is lower, its main frequency is closer to the structure’s natural frequency, leading to a more significant velocity response in the z-direction than in the y-direction.

4.3.3. Structural Displacement Response Analysis

The impact of blasting vibrations on the displacement deformation of the railway structure cannot be overlooked. Figure 7 depicts the displacement distribution contour map at the moment of maximum velocity in the three directions.

The displacement response observed at the rail location within the railway structure is notably diminished compared to that at the rail tie and subgrade. Displacement time history curves for the subgrade, rail tie, and rail were extracted under the influence of vibrations in different directions, as shown in Figure 8a–c. The peak displacement values in the x, y, and z directions are 0.185 cm, 0.155 cm, and 0.118 cm, respectively. The peak displacement values in all three directions are much smaller than the limits specified in the National Railway Administration’s standard TB10001-2016 “Code for Design of Railway Subgrades”, which states that “the dynamic deformation of the surface layer of the subgrade should meet ω ≤ Cω, where ω is the calculated deformation value (mm) and Cω is the deformation limit (mm), with 1 mm for ballasted tracks [22]”.

By comparing the displacement time history curves in all three directions, it can be observed that the displacement curves induced by blasting vibrations show an initial increase followed by stabilization. The displacement impact in the z direction is relatively small. In the displacement response curves for the x and z directions, the displacement response is greatest at the subgrade, followed by the rail tie, and smallest at the rail. However, in the displacement response curve for the y direction, the rail tie shows the largest displacement response, followed by the subgrade, and the smallest at the rail. This indicates that the structural displacement deformation is not only related to the characteristics of the vibration waves but is also significantly influenced by the structural properties of the railway.

4.3.4. Analysis of the Impact of Different Earthquake Wave Amplitudes on Structures

A multitude of studies have indicated that the peak velocity and primary frequency of blasting vibration waves are two critical parameters influencing the safety of structures [23]. In this study, the overall effect of the blasting vibration wave on the railway structure is relatively minor. Nevertheless, when the maximum single-section charge increases or the distance to the blasting area diminishes, the impact on the railway structure becomes more significant. To investigate the impact pattern of vibration waves on railway structures, while maintaining the main frequency and duration constant, the peak vibration velocity of the selected three-direction vibration waves is amplified by various multiples as detailed in

Table 5. Speed amplification factor.

Magnification Factor	1	2	4	8	16	32	64
X-direction/(cm·s−1)	0.169	0.338	0.676	1.352	2.704	5.408	10.816
Y-direction/(cm·s−1)	0.167	0.334	0.668	1.336	2.762	5.344	10.688
Z-direction/(cm·s−1)	0.098	0.196	0.392	0.784	1.568	3.136	6.272

and subsequently applied to the railway structure model for analysis.

Figure 9 illustrates the relationship between the peak vibration velocity of various structures and the loading speed across three axes. Analysis of Figure 9a–c indicates that as the loading speed in different directions rises, the overall peak vibration velocity of the structures increases to varying extents. The peak vibration velocity in the z-axis is relatively low. The peak vibration velocity at the rail location is also low, and its rate of increase is gradual as the loading speed escalates, suggesting that blasting vibrations have a minimal impact on the rail’s vibration. Conversely, the peak vibration velocity at the subgrade is considerably higher than at other structures. Should the loading speed escalate further, the subgrade is likely to be the first to sustain damage. When the loading speed in the x-axis reaches or exceeds 5.408 cm/s, the peak vibration velocity at the subgrade surpasses the permissible standard set by relevant regulations, posing a potential safety risk to the structure.

The relationship between the maximum displacement of various structures and the loading speed in three directions is depicted in Figure 10. Analysis of Figure 10a–c indicates that the maximum displacement in all three directions increases to varying extents with the rise in loading speed. When the loading speed in all three directions is low, there is no significant difference in the maximum displacement among different structures. However, as the loading speed gradually increases in the x and z directions, the maximum displacement at the subgrade is notably higher than at the other two locations, and the displacement changes of the track slab and rail are similar. In the y direction, the difference in the maximum displacement change between structures is more pronounced, and the overall displacement response of the structure in the z direction is smaller. When the loading speed in the x and y directions exceeds 3 cm/s, the maximum displacement at the subgrade surpasses 1 mm, exceeding the allowable standard as per relevant regulations, rendering it susceptible to damage.

Under the influence of peak velocity and dominant frequency of blast vibrations, the railway structure exhibits various displacement and velocity responses due to its structural characteristics. Numerical simulations indicate that the inherent frequency of the railway structure is 3.016 Hz. As the peak velocity of blast vibrations rises and the frequency approaches, the structure’s velocity and displacement increase at varying rates, contingent on the structure’s inherent characteristics. The increase becomes more significant with higher loading speeds. Considering the peak velocity and maximum displacement of the vibrating structure, it is advisable to control the blast vibration velocity below 3 cm/s. Additionally, based on the maximum single charge used in mining area blasting, the minimum safe distance can be calculated using the Sadovski formula.

The Sadovski formula [24] can be expressed as follows:

$$V=K{{\displaystyle \frac{\sqrt[3]{Q}}{R}}}^{\alpha }$$

(3)

In this formula, V represents the vibration velocity of the medium particles, measured in cm/s; Q is the maximum amount of explosive charge in a single segment, measured in kg; R is the distance from the blast center, measured in meters; and K and α are coefficients and attenuation indices related to the terrain and geological conditions between the blast area and the measurement point, respectively.

The maximum single charge amount for the mine is 95 kg. Based on the blasting vibration velocity detection results, it is known that K and α are 208 and 1.69, respectively. After calculation, the minimum safety distance is found to be 138 m.

5. Conclusions

(1) The analysis of vibration test data and simulation results indicates that the peak velocities and displacements generated in the railway structure are significantly below the regulatory limits specified in relevant standards. Specifically, the maximum recorded vibration velocity of 0.54 cm/s at the rail-sleeper interface in the x-direction and the maximum displacement of 0.185 cm at the subgrade are well within safe operational thresholds. These findings confirm that the current blasting activities have a minimal impact on the structural integrity of the railway.

(2) Among the three vibration directions, the x-direction has the most significant impact on the railway structure. This is attributed to the larger peak horizontal radial velocity generated by blasting and the relatively lower dominant frequency compared to other directions. The z-direction also exhibits notable responses due to its closer proximity to the natural frequency of the railway structure.

(3) A comparative analysis of the displacement and velocity responses of the structure under different amplitudes of vibration waves reveals that the structure exhibits varying increasing trends, which are significantly correlated with the characteristics of the vibration waves and the structure itself. Based on relevant codes and standards, and considering the peak velocity and displacement generated by the structure, it is recommended to control the blast vibration velocity to below 3 cm/s and maintain a minimum distance of 138 m between the blast zone and the railway.

(4) Although the impact of blasting in the mining area on the safety of nearby railways is currently relatively small, the cumulative effects of multiple blasts on the railway structure should be taken into account. To minimize the impact of blast vibrations on nearby railway structures, it is recommended to optimize drilling and explosive charge arrangements by controlling charge height and regulating explosive quantities per blast and per segment. Additionally, implementing pre-split blasting can create buffer cracks to mitigate vibration propagation. Furthermore, the blasting workface should be oriented perpendicular to the railway alignment, and a safe distance must be maintained between the blasting zone and railway structure to ensure structural integrity.