Shuangjiangkou Hydropower Station Research Articles

An ICEEMDAN-WPD based denoising method for MS signals and its engineering application

ABSTRACT The complex installation environments for microseismic (MS) monitoring systems generate significant noise in MS signals, hindering accurate event localization. This study proposes a noise reduction method combining improved complete ensemble empirical mode decomposition with adaptive noise and wavelet packet decomposition (ICEEMDAN-WPD). The signal is initially processed with ICEEMDAN to obtain intrinsic modal functions (IMFs), which are components ordered from high to low frequencies. The correlation between the original signal and each IMF is evaluated and low-correlation IMFs are eliminated for initial noise reduction. Additionally, the WPD method further decomposes and filters the highly correlated IMFs for secondary noise reduction, enhancing the noise reduction effect. Ultimately, the signal formed by reconstructing the secondary noise reduction IMF is the complete ICEEMDAN-WPD method filtered signal. The simulation results indicate that the ICEEMDAN-WPD method enhances the signal-to-noise ratio (SNR) and preserves the original signal characteristics to the greatest extent, demonstrating a significant noise reduction capability. In particular, the application of this method to the noise reduction process of MS signals from Shuangjiangkou hydropower station has led to a significant improvement in the accuracy of subsequent MS events localization. The research results can provide reference for similar signal noise reduction processing.

Cloud inversion analysis of surrounding rock parameters for underground powerhouse based on PSO-BP optimized neural network and web technology

Aiming at the shortcomings of the BP neural network in practical applications, such as easy to fall into local extremum and slow convergence speed, we optimized the initial weights and thresholds of the BP neural network using the particle swarm optimization (PSO). Additionally, cloud computing service, web technology, cloud database and numerical simulation were integrated to construct an intelligent feedback analysis cloud program for underground engineering safety monitoring based on the PSO-BP algorithm. The program could conveniently, quickly, and intelligently carry out numerical analysis of underground engineering and dynamic feedback analysis of surrounding rock parameters. The program was applied to the cloud inversion analysis of the surrounding rock parameters for the underground powerhouse of the Shuangjiangkou Hydropower Station. The calculated displacement simulated with the back-analyzed parameters matches the measured displacement very well. The posterior variance evaluation shows that the posterior error ratio is 0.045 and the small error probability is 0.999. The evaluation results indicate that the intelligent feedback analysis cloud program has high accuracy and can be applied to engineering practice.

BACK ANALYSIS AND STABILITY PREDICTION OF SURROUNDING ROCK DURING EXCAVATION OF THE SHUANGJIANGKOU UNDERGROUND POWERHOUSE

The underground powerhouse of the Shuangjiangkou hydropower station is one of the largest caverns under construction in China, and its stability during construction is crucial for safe construction. To study the stability of the surrounding rock during excavation, the displacement and stress of the surrounding rock were monitored by multi-point displacement meters and bolt stress meters. Based on the monitoring data, the elastic modulus, Poisson’s ratio, friction angle, and cohesion of surrounding rock were inversely analyzed by the PSO-BP algorithm. Then, the back-analyzed parameters were used to simulate the subsequent excavations and predict the stability of surrounding rock during the following construction. The analysis results show that the surrounding rocks were generally stable during the initial four stages of excavation, and the main factors affecting their stability were blasts and unfavorable geological structures, including the lamprophyre vein and the F1 fault. These unfavorable geological structures also significantly decrease the mechanical parameters of surrounding rock as demonstrated by back analysis, and the stability prediction results show that the omnibus bar cave and the tailrace tunnel were at the greatest risk of instability during the subsequent excavations. This study provides a practical analysis for engineering excavation of the underground caverns.

Prediction of brittle rock failure severity: An approach based on rock mass failure progress

This study presents the classification and prediction of severity for brittle rock failure, focusing on failure behaviors and excessive determination based on damage depth. The research utilizes extensive field survey data from the Shuangjiangkou Hydropower Station and previous research findings. Based on field surveys and previous studies, four types of brittle rock failure with different failure mechanisms are classified, and then a prediction method is proposed. This method incorporates two variables, i.e. Kv (modified rock mass integrity coefficient) and GSI (geological strength index). The prediction method is applied to the first layer excavation of the powerhouse cavern of Shuangjiangkou Hydropower Station. The results show that the predicted brittle rock failure area agrees with the actual failure area, demonstrating the method's applicability. Next, it extends to investigate brittle rock failure in two locations. The first is the k0+890 m section of the traffic cavern, and the second one is at K0-64 m of the main powerhouse. The criterion-based prediction indicates a severity brittle rock failure in the K0+890 m section, and a moderate brittle rock failure in the K0-64 m section, which agrees with the actual occurrence of brittle rock failure in the field. The understanding and application of the prediction method using Kv and GSI are vital for implementing a comprehensive brittle rock failure prediction process in geological engineering. To validate the adaptability of this criterion across diverse tunnel projects, a rigorous verification process using statistical findings was conducted. The assessment outcomes demonstrate high accuracy for various tunnel projects, allowing establishment of the correlations that enable valuable conclusions regarding brittle rock failure occurrence. Further validation and refinement through field and laboratory testing, as well as simulations, can broaden the contribution of this method to safer and more resilient underground construction.

Excavation response and reinforcement practice of large underground caverns within high-stress hard rock masses: The case of Shuangjiangkou hydropower Station, China

The construction of large-scale underground caverns poses numerous challenges due to their massive scale and high complexity. Among them, stability has always been a major concern during the construction process of large underground caverns within high-stress hard rock masses. It is not only influenced by the geological background of the project but also by the engineering activities during construction. This study takes the construction of the Shuangjiangkou (SJK) hydropower station as a case study and combines field investigations to summarize engineering issues and solutions under high geostress in three aspects. Firstly, it focuses on estimating and modifying the in-situ stress field of the underground caverns in the deep-cut valley area using limited geostress testing data and the observed failure phenomena in the pilot tunnel. Secondly, it discusses the typical failure phenomena of caverns under high geostress, including global stress-induced failures and local vein-controlled failures, as well as the corresponding failure mechanisms and treatment measures. Finally, it addresses the special failure phenomena occurring in the protective layer of the rock-anchored beam and optimizes the excavation scheme based on the observed failure patterns. The research results and solutions provided in this study, based on the case of the SJK hydropower station, are expected to serve as a reference for subsequent construction of large underground caverns within high-stress hard rock masses.

Investigation on the failure mechanism of a tunnel entrance high-steep slope with ultra-large wedge blocks based on discrete element method

An unstable wedge block with a volume of approximately 1,200,000 m3, intersected by an anti-dipped large fault and two outward-dipped faults, has been identified on the high-steep slope at the entrance of the tunnel spillway of the Shuangjiangkou hydropower station in China, a region characterized by high tectonic stresses. In this study, kinematic analysis was first conducted to preliminarily assess the possibility of block sliding, and then a three-dimensional discrete element code (3DEC) was utilized to analyze the mechanism of block instability during sequential excavation and reinforcement. The results showed that block sliding is caused by continuous excavation and deterioration of the mechanical properties of the bottom sliding surface. The failure behavior of the slope is primarily governed by the wedge block, which slides along the intersection line of two outward-dipped faults. After the excavation of Layers 1–4, the shear displacements of the faults exhibited accelerated and abrupt characteristics. Finally, the pretension cable proved effective in restraining block sliding, increasing the factor of safety for the slope from 1.16 to 1.28 after complete excavation and reinforcement. This study offers significant insights into the analysis of failure mechanisms in similar engineering challenges.

Shaping characteristics of excavation contours in sequential controlled fracture blasting of rock-anchored beams in Shuangjiangkou underground powerhouse

Influences of high in-situ stress generally need to be considered when excavating deep underground caverns. The dynamic fracture behaviors of rocks under blast loads were investigated by using the rock-anchored beam excavation in underground powerhouses of Shuangjiangkou Hydropower Station in Sichuan Province, China as the engineering background. To solve the problems of the poor blasting breakage effect of rocks and the difficulty in protecting surrounding rocks during excavation, mechanical properties of granite under static and dynamic loads were investigated and the sequential controlled fracture blasting (SCFB) method was adopted during in-situ tests. Based on the Riedel-Hiermaier-Thoma constitutive model and the strength criterion, software LS-DYNA was employed to simulate the dynamic propagation of blasting-induced cracks. The contour shaping effect obtained via numerical simulation is generally consistent with the test results. The results show that SCFB can to some extent control the direction of crack initiation and rock fracture behavior of the blasthole wall cracks and the spacing of successive bursting holes is about 10 times the diameter of the blastholes when the cracks between the blastholes are shaped the best effect. Moreover, the magnitude and direction of principal in-situ stress can both affect the propagation path and length of blasting-induced cracks. The results of the research on the excavation and construction of deeply buried underground caverns have a certain reference value.

The criterion for dividing the surrounding rock EDZs of underground caverns based on the energy dissipation degree.

An energy calculation parameter named the energy dissipation degree (RUd) is introduced based on the analysis of the energy dissipation mechanism and energy evolution characteristics during conventional triaxial tests of the granite of Shuangjiangkou. The deviatoric stress‒strain curve of rock can be divided into five stages using four stress thresholds (crack closure stress σcc, crack initiation stress σci, damage stress σcd and peak stress σp), which also correspond to the four RUd thresholds (RUdc, RUdi, RUdd and RUdp) on the energy dissipation degree-strain curve. A given stress threshold increases with increasing confining pressure; however, a given RUd threshold is basically stable under different confining pressures. Then, a new criterion for dividing the excavation damaged zones (EDZs) in the rock surrounding underground caverns based on the monotonically increasing characteristics of the energy dissipation degree‒axial strain relationship curve is proposed, and it allows for the classification of the surrounding rock into five types of zones through quantitative analysis of the RUd thresholds. Based on the criterion for dividing the EDZs of the surrounding rock mass of the underground cavern, the EDZs of the surrounding rocks of the underground cavern group of the Shuangjiangkou Hydropower Station are analyzed. The distribution characteristics of the EDZs of the rock surrounding underground caverns obtained by numerical simulation calculations based on RUd are basically the same as those obtained by in situ elastic wave tests. However, the RUd-based method for classifying the EDZs of the surrounding rock has the obvious advantage of being able to probe the boundaries of the undamaged zone (UDZ) of the surrounding rock more explicitly, while the method based on wave velocity testing is not sufficiently explicit. The damage zoning of the surrounding rock based on RUd can provide support design advice for the excavation of the surrounding rock, such as the support method, the length of the free section and anchor section of the prestressing anchor, etc.

Mechanical characteristics of failure and rockburst proneness of fractured granite from Shuangjiangkou hydropower station under triaxial loading and unloading

Mechanical characteristics of failure and rockburst proneness of fractured granite from Shuangjiangkou hydropower station under triaxial loading and unloading

Characterizing Rockbursts and Analysis on Hilbert-Huang Transform Spectrum of Microseismic Events, Shuangjiangkou Hydropower Station, Based on Microseismic Monitoring

The Shuangjiangkou hydropower station in China has complex geological conditions with high in situ stress. During the tunnel excavation, rockbursts occurred frequently, which seriously affected construction progress. Microseismic (MS) monitoring technology was used to explore rock MS activities to predict rockbursts. The MS monitoring system can capture a large number of MS signals. Based on Hilbert–Huang transform (HHT) instantaneous frequency analysis technology, using MATLAB software (R2022a) to write a program to convert the MS waveform, the frequency and energy characteristics of MS signals at a certain time can be obtained. By analyzing the frequency and energy characteristics of every event, the microseism active areas can be determined, and then rockbursts can be predicted scientifically. This paper selected two different construction sites, which were the main powerhouse and the access tunnel in the main powerhouse, as the research background. Introducing HHT instantaneous time–frequency analysis technology conducted MS event dynamic analysis and predicted rockbursts. The HHT spectrum scientifically and comprehensively displayed MS signal frequency characteristics at a certain time and reflected the change laws of signal instantaneous energy and local abrupt change information. The results indicated that some parameter anomalies in the event spectrum can predict rockbursts. For complex tunnel construction conditions, the HHT time–frequency analysis technology can realize a new idea of using a single-channel signal to predict rockbursts, which was very meaningful.

Inversion Analysis of the In Situ Stress Field around Underground Caverns Based on Particle Swarm Optimization Optimized Back Propagation Neural Network

The in situ stress distribution is one of the driving factors for the design and construction of underground engineering. Numerical analysis methods based on artificial neural networks are the most common and effective methods for in situ stress inversion. However, conventional algorithms often have some drawbacks, such as slow convergence, overfitting, and the local minimum problem, which will directly affect the inversion results. An intelligent inverse method optimizing the back-propagation (BP) neural network with the particle swarm optimization algorithm (PSO) is applied to the back analysis of in situ stress. The PSO algorithm is used to optimize the initial parameters of the BP neural network, improving the stability and accuracy of the inversion results. The numerical simulation is utilized to calculate the stress field and generate training samples. In the application of the Shuangjiangkou Hydropower Station underground powerhouse, the average relative error decreases by about 3.45% by using the proposed method compared with the BP method. Subsequently, the in situ stress distribution shows the significant tectonic movement of the surrounding rock, with the first principal stress value of 20 to 26 MPa. The fault and the lamprophyre significantly influence the in situ stress, with 15–30% localized stress reduction in the rock mass within 10 m. The research results demonstrate the reliability and improvement of the proposed method and provide a reference for similar underground engineering.

Stability analysis of surrounding rock mass in underground powerhouse considering damage effect of microfractures

A high-precision microseismic (MS) monitoring system was built to monitor surrounding rock microfractures in the underground powerhouse on the left bank of Shuangjiangkou Hydropower Station. The surrounding rock damage area with spatiotemporal clustering of MS activities was studied for qualitative analysis of the damage mechanism of surrounding rock microfractures, based on the source parameters of MS events. The surrounding rock microfracture scale characterized by the source radius of MS events was considered to establish the constitutive relation. MS information was imported into the model for numerical analysis using fast Lagrangian analysis of continuain 3 dimensions (FLAC3D). The results indicated that the numerical simulation results considering MS damage can better reflect the actual situation of the field. The surrounding rock microfractures mainly showed mixed failure characteristics. Shear failures appeared in localized areas while the fracture scale of sections from K0–33 m to K0–15 m on the vault was large. The deformation increment caused by microfracture damage in the shallow surrounding rock of the top arch accounted for 10%–13%, and the stress decrement in the surrounding rock caused by microfracture damage accounted for about 10%.

Research on Temporal and Spatial Distribution Characteristics of Microseismic Events of Slip-Type Rockburst

Based on the microseismic monitoring data of underground cavern of Shuangjiangkou Hydropower Station, the internal relationship between rockburst and microseismic events is analyzed and the occurrence mechanism of slip-type rockburst in underground cavern of Shuangjiangkou Hydropower Station is analyzed through the change of microseismic monitoring b value to warn the risk level of rockburst. The results show that microseismic events are closely related to excavation activities, and the change of b value reflects the rockburst risk level. The smaller the b value of microseismic events is, the more large magnitude events is and the greater the possibility of rockburst is. The slip-type rockburst was mainly affected by structural plane; it is due to the accumulation of elastic strain energy at the structural plane and the sudden release under the action of unloading or disturbance, driving the block on the structure surface fast slide, mainly manifested as the sliding of large blocks of surrounding rock, and forming a “V” shape pit blasting or cuneate blasting crater, as well as destruction with crackle. Compared with the strained rockburst, the damage is more serious. The research results can provide reference for rockburst prediction and prevention in similar deep rock engineering.

Strength and Energy Evolution Law of Deep-Buried Granite Under Triaxial Conditions

With the increasing global demand for clean and renewable energy sources, many underground hydropower caverns are built in deep mountain valleys in high-stress regions. The evolution of the mechanical properties of the surrounding rock of underground caverns under high-stress excavation requires urgent investigation. According to the deep-buried granite in the underground caverns of the Shuangjiangkou hydropower station, triaxial tests under confining pressures of 10, 30, 40, and 50 MPa were conducted by the MTS815 rock mechanics test system. Based on the stress–strain curve, the evolution law of the strength parameters of rock samples with the crack volume strain and energy with the energy consumption ratio under different confining pressures was analyzed. Our results showed that the stress–strain curve of the sample is divided into five stages with four characteristic points: the closed point, initiation point, volume expansion point, and peak point. The strength of each stage increases with an increase in the confining pressure. In addition, the failure of this granite is characterized by apparent shear failure. The internal friction angle and the cohesion increase rapidly with the increase in the crack volume strain, and they gradually tend to be constant. Furthermore, the confining pressure profoundly influences energy evolution during the loading in the stable and unstable crack growth stages. In these stages, total energy, dissipated energy, and elastic strain energy increase with an increase in the confining pressure. Finally, the energy consumption ratio can represent the preliminary criterion of rock failure in terms of energy. With the increase in the confining pressure, the energy consumption ratio of rock samples gradually increases to approximately 1.0 at the peak stress point. The research results can provide a reference for the instability prediction of surrounding rock masses of high-stress underground caverns.

Dynamic cumulative damage characteristics of deep-buried granite from Shuangjiangkou hydropower station under true triaxial constraint

Deformation and failure of rocks under loading is an energy- driven progressive process of damage evolution, and the abrupt energy release from rocks storing strain energy under high- geostress conditions is a determinant inducing catastrophic effects. Therefore, studying the progressive fracture mechanism of rocks from the perspectives of energy accumulation and dissipation is conducive to prediction and evaluation of catastrophic effects of surrounding rocks. In this study, granite was taken from an underground powerhouse of Shuangjiangkou Hydropower Station, Sichuan Province, China to study cumulative damage characteristics of the rock under dynamic triaxial loading by considering factors, such as in-situ stress, number of impacts and strain rate through use of a true-triaxial split Hopkinson pressure bar (SHPB) as a loading device and a three- dimensional (3-d) X-ray computed tomography (CT) system. Mechanisms inducing catastrophic effects in deep-buried granite were explored from the perspectives of energy evolution, progressive damage, and failure mode. The research results demonstrate that under a single impact, the dynamic compressive strength of granite increases exponentially with the impact load, while the rate of increase gradually decreases. Moreover, failure effects of the rock are strengthened with increasing impact load. Under multiple impacts, the energy absorbed by the rock shows cumulative effects and the amount of energy dissipated per unit volume increases. Furthermore, progressive damage is significant, and the damage evolution exhibits obvious anisotropy. Under dynamic triaxial loading, shear failure predominates in granite. The confining pressure inhibits damage to the rock during static loading and the rock is severely damaged in the direction of its free face, where it is more likely to induce catastrophic effects. The 3-d visualization of fracture networks reveals the progressive damage process of granite under dynamic triaxial loading and the cumulative absorbed energy and volume of microcracks in rock increase linearly with the number of impacts. Therefore, taking cumulative damage effects caused by frequent blasting excavation into consideration can better evaluate catastrophic effects, such as rock burst or rib spalling of surrounding rock of side wall of deep-buried caverns in Shuangjiangkou Hydropower Station.

Damage mechanism and stability analysis of rock mass in the high geo-stress tunnel subjected to excavation

High geo-stresses and complicated geological conditions are two typical characteristics in the traffic tunnel of the tailrace surge chamber at the Shuangjiangkou hydropower station, Southwest China. Rock failures such as spalling and rockbursts induced by excavation were encountered repeatedly in this tunnel. To evaluate the stability of rock mass of the tunnel during excavation, the high-precision microseismic (MS) monitoring technology was introduced. Through analysing the tempo-spatial distribution characteristics of MS events, the main damage areas and their influencing factors were studied. The rock fracturing mechanisms of MS clusters were revealed based on the source parameters of MS events. A three-dimensional model was established to obtain the stress and deformation characteristics of rock mass. Results indicated that the MS events mainly occurred between July 10 and 26, 2017 and the energy release was higher during this period. The main damage areas of rock mass were located at the Stake K0 + 110m–K0 + 170m. Weak structures and multi-cavern effect aggravated rock mass damage subjected to excavation-unloading. Tensile failure was the main fracturing type of rock mass. Rock mass damage influenced by weak structures was especially prominent. The numerical simulation results are consistent with the MS monitoring results. The results could provide significant references for safety evaluation and construction design of similar tunnels.

Progressive failure characteristics and energy accumulation of granite with a pre-fabricated fracture during conventional triaxial loading

Deformation and failure of rocks under the loading effect is an energy-driven progressive process of damage evolution, and the abrupt energy release from rocks storing strain energy under high geostress conditions is a determinant inducing catastrophic effects. Therefore, studying the progressive fracture mechanism of rocks from the perspectives of energy accumulation and dissipation contributes to prediction and evaluation of catastrophic effects such as a rockburst. Fractured samples with different fracture dip angles were prepared using granite collected from the underground powerhouse (under maximum geostress of about 37.82 MPa) in Shuangjiangkou Hydropower Station in Dadu River Basin in China. By using these samples, the progressive failure characteristics and energy accumulation and evolution in fractured rocks during triaxial loading were studied under different stress conditions. In addition, the functional relationships of the crack initiation strength, damage strength, and peak strength of the fractured granite with the confining pressure and fracture dip angle in the loading process were established. The evolution of volumetric strain upon cracking corresponding to the peak stress with the confining pressure and fracture dip angle was discussed. Furthermore, the research explored the intrinsic relationships between the acoustic emission (AE) events and mechanical characteristics of the fractured granite during fracturing thereof. The correspondence of the AE count rate and cumulative energy count with various stages in the progressive failure of the rock was studied, and the evolution of the elastic strain energy and dissipated energy in the rock can be predicted based on the strength, deformation, and AE characteristics. Besides, effects of the confining pressure and the dip angle on the AE characteristic signals were investigated. Finally, the accumulation and evolution of the input energy, elastic strain energy, and dissipated energy of fractured granite in the pre-peak stage during triaxial loading were revealed using an energy analysis. Moreover, the relationships of the eigenvalues of elastic strain energy and dissipated energy of fractured granite with the confining pressure and fracture dip angle were determined.

Influence of Discontinuities on Rock Failure under Blasting at Shuangjiangkou Hydropower Station

The underground caverns of Shuangjiangkou hydropower station are under complex geological conditions. During excavation, the stability of the tunnels is severely affected by problems, such as blasting impact and excavation unloading, resulting in abnormal deformation at different locations. On the basis of on-site measurement, the characteristics of rocks at the main powerhouse and the main transformer room are compared through dynamic tests, and a numerical model is established using discrete element method (DEM) to analyze the special influence of fault SPD9-f1 on the deformation after excavation. It is revealed that the surrounding rock of the main powerhouse has stronger impact resistance than that of the main transformer room and that the existence of fault SPD9-f1 accounts for the abnormal deformation. In this study, the failure characteristics and mechanism of surrounding rock deformation controlled by stress and fault are revealed, providing important references for the subsequent excavation and support design of underground projects.

Deformation and failure analysis of surrounding rock mass in deep buried tunnels subjected to excavation

With the rapid development of underground engineering, the construction of hydraulic tunnel is faced with complex geological conditions. Rock burst and deformation have become the bottleneck of engineering construction. The study of deformation and failure mechanisms of surrounding rock mass during the excavation of deep buried tunnel has become important for the field of underground engineering. The traffic tunnel of Shuangjiangkou hydropower station is studied to identify the failure mechanism of surrounding rock mass of deep buried tunnel. We introduced microseismic monitoring technology to delineate potential risk areas and reveal the space-time evolution of microfractures. The failure type of the surrounding rock is determined by source parameters. The relationship between surrounding rock deformation and excavation dynamic response is analyzed based on the geological and microseismic data. The results show that the 3D microseismic visualization model can realize the advanced detection of the internal damage of surrounding rock. The source parameters reveal that tensile failure is the main form of failure in the tunnel surrounding rock. Strong unloading and poor geological conditions are the main factors affecting the stability of surrounding rock mass. The study combines microseismic monitoring with field investigation, and then comprehensively evaluates the stability of the tunnel surrounding rock providing a reference for similar underground engineering.

Rockburst prediction and analysis of activity characteristics within surrounding rock based on microseismic monitoring and numerical simulation

The access tunnel in the main powerhouse of the Shuangjiangkou hydropower station is located in an area with high in-situ stress and complex geological conditions in Southwest China. Strain-structure rockbursts occurred frequently and posed serious threats to the safety of personnel and equipment during the tunnel excavation. The maximum depth of the rockburst failure reached 1.8 m at the left sidewall of the tunnel. A three-dimensional microseismic (MS) monitoring technology was introduced to monitor microcracks within the tunnel surrounding rock in real time. Using Matlab software to write a program, the main frequency values of MS signals were extracted. Based on MS monitoring, some source parameters were obtained. Three parameters, including apparent stress, apparent volume and main frequency value, were used to analyze the activity state within the surrounding rock. This method had a high time resolution and can guide the on-site construction in real time. The combination of the three parameters can better characterize different damage characteristics of the surrounding rock in real time. When the apparent stress of some events was relatively high, the apparent volume of some events was relatively large and the main frequency values of some events were relatively low, the risk of rockbursts was relatively high. Finally, a 3D numerical simulation software (RFPA3D) was used for a numerical calculation to explore strain-structure rockburst mechanisms. An area where the rockburst risk was relatively high and rockburst prediction was relatively difficult was delineated, and this paper provided a new idea for predicting the stronger strain-structure rockbursts. Understanding of activity state within surrounding rock is very important for controlling rockburst occurrence or weakening rockburst strength. The research results have significant value for safe and efficient construction on site.