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To research the macroscopic deformation of rock microseismic damage, a high-precision microseismic monitoring system was established on the left bank slope of the Baihetan hydropower station in Southwestern China. Based on the microseismic monitoring and field deformation data, the seismic source radius was applied to characterize the rock fracture...
Citations
... If the trend tends to increase, it indicates that stress accumulation occurs in this area, indicating an increase in the rock mass instability and increased risk of rockburst disasters. Zhang et al. [57] studied the microseismic evolution characteristics of an underground powerhouse during excavation and found that the apparent stress of the surrounding rock increased significantly before the appearance deformation. Ma et al. [58] established an EMS method for rockburst prediction using a combination of seismic energy, seismic moment, and apparent stress. ...
Due to the different geological conditions and construction methods associated with different projects, rockbursts in deep-buried tunnels often present different precursor characteristics, bringing major challenges to the early warning of rockbursts. To adapt to the complexity of engineering, it is necessary to review the latest advancements in rockburst early warning and to discuss general early warning methods. In this article, first, microseismic monitoring and localization methods applicable under tunneling construction are reviewed. Based on the latest engineering examples and research progress, the microseismic evolution characteristics of the rockburst formation process are summarized, and the formation process and mechanism of structure-type and delayed rockbursts are analyzed. The different methods for predicting the risk and level of rockbursts using microseismic indices are reviewed, and the implementation methods and application cases for predicting potential rockburst areas and rockburst probability based on a mechanical model are expounded. Finally, combined with the new practice in early warning methods, development directions for the early warning of rockbursts are put forward.
... Various rock engineering hazards such as rockbursts, soft rock deformation, and harmful gases have been frequently encountered during construction, and these hazards severely threaten the safety of personnel and equipment. Recently, microseismic techniques have gradually been widely adopted for practical monitoring and early warning technology; in particular, such techniques are widely used for various rock engineering applications in China, such as projects involving rock slopes, hydropower stations and high concrete arch dams (Dong et al. 2019;Ma et al. 2015;Zhuang et al. 2019). In addition, microseismic analysis has proven to be a very useful tool for understanding underground rock failure processes since the twentieth century (Ge et al. 2009;Ghosh and Sivakumar 2018;Milev and Spottiswoode 2002;Urbancic and Trifu 2000). ...
Microseismic technology has widely been used in many rock engineering applications to shield workers from engineering hazards and monitor underground construction. To avoid the heavy workloads imposed by the manual recognition of many microseismic signals, this study proposes a new end-to-end training network architecture to automatically identify microseismic events. A dataset including not only easily identifiable microseismic signals but also barely distinguishable nontypical data has been collected from a practical rock engineering project for training and testing the network model. The applicability of various networks for this task is discussed to select the best method for microseismic recognition. We modify the residual skip connections to make them more suitable for the signal classification task. Then, the novel depthwise spatial and channel attention (DSCA) module is proposed. This module can autonomously learn how to weight information with different levels of importance, similar to human attention, which greatly improves the network performance without incurring additional computational costs. Theoretically, it can be a useful tool to replace traditional denoising algorithms and model the interdependencies between the different channels of a multichannel signal. Furthermore, the DSCA module and the modified residual connections are combined with a traditional convolutional network to obtain a novel network architecture named ResSCA and the results of comparative experiments are presented. Finally, single- and multichannel models are constructed based on ResSCA, which achieved improved accuracy rates. Their advantages and drawbacks are analyzed. This study presents a modified network architecture suitable for identifying and classifying complex signals to enable intelligent microseismic monitoring, which is valuable for various rock engineering applications.
... A geomechanical model containing various faults and weak structural planes was established, while a numerical simulation was conducted under normal water load condition through FLAC3D processing to analyze the slope stability [33][34][35][36][37][38]. To research the macroscopic deformation of the left bank slope of the Baihetan Hydropower Station in Southwestern China, the unloading deformation of the left bank abutment rock mass was studied through FLAC numerical calculations [39]. ...
The high-steep rock slope stability is one of the key technologies in the construction of water conservancy and hydropower projects, which affects and restricts the development of hydraulic resources and the construction of hydropower projects. In this paper, a three-dimensional numerical model was built incorporating stratigraphy, geological structures, and the inverted rock mechanical parameters to perform displacement, stress, and plastic zone analyses for an excavated slope in China using the FLAC3D software. The numerical simulation results after slope excavation show that the deformation near the fault fracture zone is the largest, ranging from 350 mm to 380 mm. The compressive stress is concentrated on the slope foot and the connecting part, the stress value is 2 MPa∼5 MPa, there is a large tensile stress area in the slope, and the tensile stress value is 0 MPa∼0.4 MPa. The plastic zone of the slope is concentrated near the fault F6 and the structural influence zone, and the rock mass of the slope basically enters the plastic state. On this basis, the deformation mechanism of slope was analyzed, while the internal and external factors affecting the slope deformation were described in detail. This work would provide an effective reference basis for slope stability evaluation and treatment of similar hydropower stations.
... Brittle failure of rock masses triggered by engineering activities and natural changes results in the energy release with the spreading of a seismic wave, which is called a microseismic (MS) event [1]. To better understand the relationship between rock fracturing and production activities, MS monitoring, a real-time monitoring technique, has been widely applied in various rock engineering projects, such as mining engineering [2], underground caverns [3,4], slope stability [5,6], oil and gas extraction [7,8], etc. The technique utilizes multiple sensors installed in the monitoring borehole to record MS signals for the exploration of internal development characteristics of rock rupture. ...
Microseismic (MS) signals recorded by sensors are often mixed with various noise, which produce some interference to the further analysis of the collected data. One problem of many existing noise suppression methods is to deal with noisy signals in a unified strategy, which results in low-frequency noise in the non-microseismic section remaining. Based on this, we have developed a novel MS denoising method combining variational mode decomposition (VMD) and Akaike information criterion (AIC). The method first applied VMD to decompose a signal into several limited-bandwidth intrinsic mode functions and adaptively determined the effective components by the difference of correlation coefficient. After reconstructing, the improved AIC method was used to determine the location of the valuable waveform, and the residual fluctuations in other positions were further removed. A synthetic wavelet signal and some synthetic MS signals with different signal-to-noise ratios (SNRs) were used to test its denoising effect with ensemble empirical mode decomposition (EEMD), complete ensemble empirical mode decomposition (CEEMD), and the VMD method. The experimental results depicted that the SNRs of the proposed method were obviously larger than that of other methods, and the waveform and spectrum became cleaner based on VMD. The processing results of the MS signal of Shuangjiangkou Hydropower Station also illustrated its good denoising ability and robust performance to signals with different characteristics.
... The calculation of the FOS first depends on the limit equilibrium method (LEM), which is based on statistics [6][7][8]. Then, the finite element method (FEM) is used to calculate the FOS to provide detailed stress and strain information [9][10][11][12][13][14][15]. However, both the LEM and FEM can only be used before failure, and cannot show the post-failure behavior of a sliding mass because LEM cannot calculate strain and displacement, and FEM has limitations when it comes to large-deformation analysis. ...
Forecasting the occurrence potential of landslides is important but challenging. We aimed to forecast the failure potential of the Helong landslide, which is temporarily stable but has clearly deformed in recent years. To achieve the goal, we used reconnaissance, remote sensing, drilling, laboratory tests, topographical analysis, and electrical resistivity tomography (ERT). The factor of safety (FOS) of the slope was first calculated using a limit equilibrium method. The results show the FOS of the slope was 1.856 under natural conditions, 1.506 under the earthquake conditions, 1.318 under light rainfall, 0.986 under heavy rainfall, 1.075 under light rainfall and earthquake, and 0.832 under simultaneous heavy rainfall and earthquake. When the FOS is less than 1.35, the slope is considered metastable according to the Technical Code for Building Slope Engineering (GB50330-2013) published by the Chinese Ministry of Housing and Urban-Rural Development. Based on the drilling data and digital elevation data, a three-dimensional discrete element method (DEM) model was used to simulate potential landslides. The simulation was used to examine catastrophic slope failure under heavy rainfall conditions within a range of friction coefficients and the corresponding affected areas were determined. Then, we analyzed a typical run-out process. The dynamic information of the run-out behavior, including velocity, run-out distance, and depth, were obtained, which is useful for decision support and future landslide hazard assessment.
