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Excavation-induced microseismicity and rockburst occurrence in deep underground projects provide invaluable information that can be used to warn rockburst occurrence, facilitate rockburst mitigation procedures, and analyze the mechanisms responsible for their occurrence. Based on the deep parallel tunnels with the maximum depth of 1890 m created as part of the Neelum-Jhelum hydropower project in Pakistan, similarities and differences on excavation-induced microseismicity and rockburst occurrence between parallel tunnels with soft and hard alternant strata are studied. Results show that a large number of microseismic (MS) events occurred in each of the parallel tunnels during excavation. Rockbursts occurred most frequently in certain local sections of the two tunnels. Significant differences are found in the excavation-induced microseismicity (spatial distribution and number of MS events, distribution of MS energy, and pattern of microseismicity variation) and rockbursts characteristics (the number and the spatial distribution) between the parallel tunnels. Attempting to predict the microseismicity and rockburst intensities likely to be encountered in subsequent tunnel based on the activity encountered when the parallel tunnel was previously excavated will not be an easy or accurate procedure in deep tunnel projects involving complex lithological conditions.
Guang-Liang Feng; Bing-Rui Chen; Quan Jiang; Ya-Xun Xiao; Wen-Jing Niu; Peng-Xiang Li. Excavation-induced microseismicity and rockburst occurrence: Similarities and differences between deep parallel tunnels with alternating soft-hard strata. Journal of Central South University 2021, 28, 582 -594.
AMA StyleGuang-Liang Feng, Bing-Rui Chen, Quan Jiang, Ya-Xun Xiao, Wen-Jing Niu, Peng-Xiang Li. Excavation-induced microseismicity and rockburst occurrence: Similarities and differences between deep parallel tunnels with alternating soft-hard strata. Journal of Central South University. 2021; 28 (2):582-594.
Chicago/Turabian StyleGuang-Liang Feng; Bing-Rui Chen; Quan Jiang; Ya-Xun Xiao; Wen-Jing Niu; Peng-Xiang Li. 2021. "Excavation-induced microseismicity and rockburst occurrence: Similarities and differences between deep parallel tunnels with alternating soft-hard strata." Journal of Central South University 28, no. 2: 582-594.
The microseismic (MS) monitoring technique is widely used in deep tunnels for rock mass stability monitoring and disaster warning. MS source location is the basis of the MS monitoring technique. This study investigates the effect of arrival-time picking on MS source location in a tunnel. A total of 1000 MS sources, 12,000 arrival-time pickings, and particle swarm optimization are used. Accordingly, 3796 source-locating operations are conducted for each MS source. The results show that the number of arrival-time pickings and their mode of combination significantly affect the accuracy and the stability of MS source location in a tunnel. The optimal location cannot be obtained when using the arrival-time pickings with the smallest errors. The optimal location accuracy decreases with the increase in the number of arrival-time pickings; however, the average location accuracy increases therewith. The source location accuracy significantly changes when the number of arrival-time pickings is small. The location result becomes more stable with the increasing number of arrival-time pickings. Accordingly, a suggestion involving the usage of all arrival-time pickings for MS source location in a tunnel is provided. The results will contribute to rock mass stability monitoring and disaster warning in tunnels using the MS monitoring technique.
Guang-Liang Feng; Ya-Xun Xiao; Man-Qing Lin; Yang Yu; Yu Fu. Microseismic source location in tunnels: Effect of arrival-time picking. IOP Conference Series: Earth and Environmental Science 2020, 570, 052049 .
AMA StyleGuang-Liang Feng, Ya-Xun Xiao, Man-Qing Lin, Yang Yu, Yu Fu. Microseismic source location in tunnels: Effect of arrival-time picking. IOP Conference Series: Earth and Environmental Science. 2020; 570 (5):052049.
Chicago/Turabian StyleGuang-Liang Feng; Ya-Xun Xiao; Man-Qing Lin; Yang Yu; Yu Fu. 2020. "Microseismic source location in tunnels: Effect of arrival-time picking." IOP Conference Series: Earth and Environmental Science 570, no. 5: 052049.
The drying-wetting cycles caused by operation of the Three Gorges Reservoir have considerable effect on the deterioration of reservoir bank rock mass, and the degradation of reservoir rock mass by the drying-wetting cycle is becoming obvious and serious along with the periodic operation. At present, the strength of the rock prediction research mainly focuses on the uniaxial strength, and few studies consider the drying-wetting effect and confining pressure. Therefore, in this paper, typical sandstone from a reservoir bank in the Three Gorges Reservoir area is taken as the research object, while the drying-wetting cycle test, wave velocity test and strength test are carried out for the research on the strength prediction of sandstone under the action of the drying-wetting cycle. The results show that the ultrasonic wave velocity Vp of the sandstone has an exponential function relation with the drying-wetting cycle number n, and the initial stage of drying-wetting cycles has the most significant influence on the wave velocity. Under different confining pressures, the compressive strength of sandstone decreases linearly with the increase of the drying-wetting cycle numbers, and the plastic deformation increases gradually. The damage variable of the sandstone has a power function relation with the increase of drying-wetting cycle numbers. A traditional strength prediction model based on P-wave velocity was established combined with the damage theory and Lemaitre strain equivalence hypothesis; in view of the defects of the traditional strength prediction model, a modified model considering both the drying-wetting cycle number and confining pressures was proposed, where the calculated results of the modified model are closer to the test strength value, and the prediction error is obviously decreased. This indicated that the modified model considering the drying-wetting cycle number and confining pressure is reasonable and feasible.
Zhi-Hua Xu; Guang-Liang Feng; Qian-Cheng Sun; Guo-Dong Zhang; Yu-Ming He. A Modified Model for Predicting the Strength of Drying-Wetting Cycled Sandstone Based on the P-Wave Velocity. Sustainability 2020, 12, 5655 .
AMA StyleZhi-Hua Xu, Guang-Liang Feng, Qian-Cheng Sun, Guo-Dong Zhang, Yu-Ming He. A Modified Model for Predicting the Strength of Drying-Wetting Cycled Sandstone Based on the P-Wave Velocity. Sustainability. 2020; 12 (14):5655.
Chicago/Turabian StyleZhi-Hua Xu; Guang-Liang Feng; Qian-Cheng Sun; Guo-Dong Zhang; Yu-Ming He. 2020. "A Modified Model for Predicting the Strength of Drying-Wetting Cycled Sandstone Based on the P-Wave Velocity." Sustainability 12, no. 14: 5655.
Rockburst disasters in deep tunnels cause serious casualties and economic losses. It is a great challenge to make a warning for rockbursts in geotechnical engineering. In this work, a microseismicity-based rockburst intensity warning method is proposed that is suitable for use in deep tunnels in the initial period of microseismic (MS) monitoring. The method first involves collecting information on a sample of no more than five cases. Then, the event to be analyzed is combined with the sample events and subjected to cluster analysis. Finally, a rockburst intensity warning is generated according to the results of the cluster analysis or after a second cluster analysis. It is a comprehensive, multi-parameter rockburst intensity warning method that only needs a few rockburst cases for input which makes it suitable in the initial period of MS monitoring. The method also incorporates the novel idea of a second cluster analysis. An engineering application based on deep tunnels in the Jinping II hydropower station in Sichuan Province, China, shows that the rockburst intensity warning results based on the proposed method agree well with the actual situations in four tests carried out. The method will enrich the techniques used to warn of rockbursts based on microseismicity.
Guangliang Feng; Manqing Lin; Yang Yu; Yu Fu. A Microseismicity-Based Method of Rockburst Intensity Warning in Deep Tunnels in the Initial Period of Microseismic Monitoring. Energies 2020, 13, 2698 .
AMA StyleGuangliang Feng, Manqing Lin, Yang Yu, Yu Fu. A Microseismicity-Based Method of Rockburst Intensity Warning in Deep Tunnels in the Initial Period of Microseismic Monitoring. Energies. 2020; 13 (11):2698.
Chicago/Turabian StyleGuangliang Feng; Manqing Lin; Yang Yu; Yu Fu. 2020. "A Microseismicity-Based Method of Rockburst Intensity Warning in Deep Tunnels in the Initial Period of Microseismic Monitoring." Energies 13, no. 11: 2698.
Based on a large amount of real-time microseismic monitoring data and hundreds of rockburst cases of different types stemming from the construction of deep tunnels at Jinping Mountain Hydropower Station, Sichuan Province, China, a fractal calculation method, which is suitable for the study of linear tunnels, was proposed to investigate the self-similarity of the spatial distribution of the microseismic events occurring during the development of strain-structure slip rockbursts and strain rockbursts. The range and distribution characteristics of spatial fractal dimensions in the development process of different types of rockbursts were also compared and analyzed. The overburden above the tunnels, which are largely excavated in marble, is between 800 and 2,525 m. The results indicate that the spatial distribution of microseismic events during the evolution of rockbursts displays fractal properties. The daily spatial fractal dimensions of microseismic events decrease during the development of a rockburst, and are reduced to the minimum value as a rockburst occurs. There is an inversely proportional relationship between the daily spatial fractal dimension and microseismic energy release. The spatial fractal dimensions of microseismic events associated with a whole rockburst can be used as a basis for estimating the type of rockburst: spatial fractal dimensions greater than and less than 1.3 correspond to strain rockbursts and strain-structure slip rockbursts, respectively. For different types of rockbursts, if the intensity is higher, the spatial fractal dimension is smaller. The conclusion provides a basis for the development of a warning system for the prediction and prevention of different types of rockbursts in deep tunnels.
Yang Yu; Xia-Ting Feng; Chang-Jie Xu; Bing-Rui Chen; Ya-Xun Xiao; Guang-Liang Feng. Spatial Fractal Structure of Microseismic Events for Different Types of Rockburst in Deeply Buried Tunnels. International Journal of Geomechanics 2020, 20, 04020025 .
AMA StyleYang Yu, Xia-Ting Feng, Chang-Jie Xu, Bing-Rui Chen, Ya-Xun Xiao, Guang-Liang Feng. Spatial Fractal Structure of Microseismic Events for Different Types of Rockburst in Deeply Buried Tunnels. International Journal of Geomechanics. 2020; 20 (4):04020025.
Chicago/Turabian StyleYang Yu; Xia-Ting Feng; Chang-Jie Xu; Bing-Rui Chen; Ya-Xun Xiao; Guang-Liang Feng. 2020. "Spatial Fractal Structure of Microseismic Events for Different Types of Rockburst in Deeply Buried Tunnels." International Journal of Geomechanics 20, no. 4: 04020025.
The occurrence of rockburst is related to the surrounding rock stress and geological rock mass strength. Rockburst occurs frequently during the construction at a deep tunnel in southwest China (a tunnel with a depth of approximately 2080 m, and a length of 13 km), leading to casualties, damage to construction equipment, and schedule delays. The application of the rockburst criteria based on the stress-strength/strength-stress ratio shows that they are not suitable for the construction stage. This paper suggests a simple and feasible rockburst intensity criterion based on the Geological Strength Index (GSI) for the construction stage. In this criterion, the strength of the rock mass exposed during excavation is estimated by the Hoek-Brown criterion and is used to reflect the geological conditions of the surrounding rock, considering the influences of the joint conditions and engineering disturbance. The maximum principal stress along the tunnel is obtained by the in situ stress inversion. The ratio of the rock mass strength to the maximum principal stress (σcm/σ1) is taken as the evaluation index. The criterion is as follows: σcm/σ1 > 1.2, none rockburst; 0.75 < σcm/σ1 ≤ 1.2, slight rockburst; 0.4 < σcm/σ1 ≤ 0.75, moderate rockburst; and σcm/σ1 ≤ 0.4, intense rockburst. The engineering applications show the reliability of this rockburst intensity criterion. The results of this paper provide a reference for rockburst intensity evaluation during the construction stage of deep tunnels.
Wei Zhang; Xia-Ting Feng; Ya-Xun Xiao; Guang-Liang Feng; Zhi-Bin Yao; Lei Hu; Wen-Jing Niu. A rockburst intensity criterion based on the Geological Strength Index, experiences learned from a deep tunnel. Bulletin of Engineering Geology and the Environment 2020, 79, 3585 -3603.
AMA StyleWei Zhang, Xia-Ting Feng, Ya-Xun Xiao, Guang-Liang Feng, Zhi-Bin Yao, Lei Hu, Wen-Jing Niu. A rockburst intensity criterion based on the Geological Strength Index, experiences learned from a deep tunnel. Bulletin of Engineering Geology and the Environment. 2020; 79 (7):3585-3603.
Chicago/Turabian StyleWei Zhang; Xia-Ting Feng; Ya-Xun Xiao; Guang-Liang Feng; Zhi-Bin Yao; Lei Hu; Wen-Jing Niu. 2020. "A rockburst intensity criterion based on the Geological Strength Index, experiences learned from a deep tunnel." Bulletin of Engineering Geology and the Environment 79, no. 7: 3585-3603.
Understanding rock mechanical behaviors after thermal shock is critically important for practical engineering application. In this context, physico-mechanical properties of Beishan granite, Gansu Province, China after cyclic thermal shock were studied using digital image correlation (DIC), acoustic emission (AE) monitoring, and microscopic observation. The results show that the peak strength and elastic modulus decreased gradually with increase in thermal shock cycle. However, the above two parameters showed no further changes after 10 thermal shock cycles. The loading stress ratio (i.e. the ratio of the current loading stress level to the peak stress in this state) corresponding to the occurrence of the uneven principal strain field and the local strain concentration zone on the surface of the granite specimen decreased with increase in thermal shock cycle. Three transformation forms of the standard deviation curves of the surface principal strain were found. For granite with fewer thermal shock cycles (e.g. no more than 2 cycles), the standard deviation curves exhibited approximately exponential growth in exponential form. With increase in thermal shock cycle, the S-shaped curve was dominant. After 10 thermal shock cycles, an approximate ladder-shaped curve was observed. It is displayed that AE activity was mainly concentrated around the peak strength zone of the granite specimen when the rock samples underwent fewer thermal shock cycles. With increase in thermal shock cycle, AE activity could occur at low loading stress levels. Microscopic observation further confirmed these scenarios, which showed that more microcracks were induced with increase in thermal shock cycle. The number of induced microcracks at the edge location of the granite specimen was significantly larger than that at the interior location. Finally, a continuum damage model was proposed to describe the damage evolution of the granite specimen after cyclic thermal shock during loading.
Peiyang Yu; Peng-Zhi Pan; Guang-Liang Feng; Zhenhua Wu; Shankun Zhao. Physico-mechanical properties of granite after cyclic thermal shock. Journal of Rock Mechanics and Geotechnical Engineering 2020, 12, 693 -706.
AMA StylePeiyang Yu, Peng-Zhi Pan, Guang-Liang Feng, Zhenhua Wu, Shankun Zhao. Physico-mechanical properties of granite after cyclic thermal shock. Journal of Rock Mechanics and Geotechnical Engineering. 2020; 12 (4):693-706.
Chicago/Turabian StylePeiyang Yu; Peng-Zhi Pan; Guang-Liang Feng; Zhenhua Wu; Shankun Zhao. 2020. "Physico-mechanical properties of granite after cyclic thermal shock." Journal of Rock Mechanics and Geotechnical Engineering 12, no. 4: 693-706.
Rockbursts are a common form of disaster that occur during the construction of deep tunnels in hard rock. This is especially the case in the breakthrough stage of excavation, when even more attention should be paid to the risk of rockburst in order to ensure construction safety. This work studied the characteristics of the microseismicity associated with 10 breakthrough cases in the deep tunnels (maximal depth 2,525 m) of the Jinping-II Hydropower Station in China. The results showed that the microseismicity was relatively more active in the breakthrough period (compared with that in adjacent sections) due to the effect of working two faces in tandem and was concentrated in the breakthrough section. Furthermore, the characteristic c-value associated with the seismic energy–potency relationship was larger, indicating that the apparent stress was greater in the breakthrough section. Spatiotemporal changes in microseismicity that are associated with rockburst development were found in the breakthrough section which can be used to qualitatively warn of the risk of rockburst. Rockburst risk can be quantitatively assessed during tunnel breakthrough based on the monitored microseismicity and a quantitative method of rockburst warning. Based on results thus obtained, the rockburst risk in the breakthrough section was found to increase continuously as the distance between the two working faces decreased. When both working faces are excavated in the breakthrough section, the quantitative risk of rockburst increases significantly. However, when only one working face is in action, the quantitative risk of rockburst increases only slightly. The results of this work will be helpful in warning of impending rockbursts, and thus improving the safety of the construction process, when breakthrough is carried out in deep tunnels excavated in hard rock.
Guang-Liang Feng; Xia-Ting Feng; Bing-Rui Chen; Ya-Xun Xiao; Guo-Feng Liu; Wei Zhang; Lei Hu. Characteristics of Microseismicity during Breakthrough in Deep Tunnels: Case Study of Jinping-II Hydropower Station in China. International Journal of Geomechanics 2020, 20, 04019163 .
AMA StyleGuang-Liang Feng, Xia-Ting Feng, Bing-Rui Chen, Ya-Xun Xiao, Guo-Feng Liu, Wei Zhang, Lei Hu. Characteristics of Microseismicity during Breakthrough in Deep Tunnels: Case Study of Jinping-II Hydropower Station in China. International Journal of Geomechanics. 2020; 20 (2):04019163.
Chicago/Turabian StyleGuang-Liang Feng; Xia-Ting Feng; Bing-Rui Chen; Ya-Xun Xiao; Guo-Feng Liu; Wei Zhang; Lei Hu. 2020. "Characteristics of Microseismicity during Breakthrough in Deep Tunnels: Case Study of Jinping-II Hydropower Station in China." International Journal of Geomechanics 20, no. 2: 04019163.
During deep tunnel excavation, more than one rockburst sometimes occur in a particular area which seriously threatens construction safety. In this work, the characteristic microseismicity occurring during the development process of intermittent rockburst (more than one rockburst occurring in a particular area) and single rockburst (only one rockburst occurring in a particular area) and the associated mechanism of formation are studied. Data was collected during the construction of a railway tunnel in southwestern China. Microseismicity was recorded and analyzed before and after each rockburst (for both intermittent and single rockbursts). The Schmidt number declines heavily with time, the cumulative apparent volume rises sharply with time, and the Seismic activity is high before the rockburst. However, this characteristic microseismicity can also be found with no rockburst occurrence. Between each rockburst in an intermittent rockburst, the MS events mostly have low MS energy, i.e. whose logarithm (measured in Joules) is smaller than 3.5, and the energy stored in the rockmass of the rockburst zone is not adequately released. Therefore, there is likely to be another rockburst after the blast when high in situ stress is present. After the last rockburst of an intermittent rockburst and the single rockburst, some MS events of high MS energy, i.e. whose logarithm (measured in Joules) is larger than 3.5, occur in the deep surrounding rockmass and the energy stored in the rockmass of the rockburst zone is gradually released to a certain degree. The stress is transferred to the deep surrounding rockmass whose stability is relatively high. As a result, a subsequent rockburst is hardly likely to occur again.
Guang-Liang Feng; Xia-Ting Feng; Ya-Xun Xiao; Zhi-Bin Yao; Lei Hu; Wen-Jing Niu; Tong Li. Characteristic microseismicity during the development process of intermittent rockburst in a deep railway tunnel. International Journal of Rock Mechanics and Mining Sciences 2019, 124, 104135 .
AMA StyleGuang-Liang Feng, Xia-Ting Feng, Ya-Xun Xiao, Zhi-Bin Yao, Lei Hu, Wen-Jing Niu, Tong Li. Characteristic microseismicity during the development process of intermittent rockburst in a deep railway tunnel. International Journal of Rock Mechanics and Mining Sciences. 2019; 124 ():104135.
Chicago/Turabian StyleGuang-Liang Feng; Xia-Ting Feng; Ya-Xun Xiao; Zhi-Bin Yao; Lei Hu; Wen-Jing Niu; Tong Li. 2019. "Characteristic microseismicity during the development process of intermittent rockburst in a deep railway tunnel." International Journal of Rock Mechanics and Mining Sciences 124, no. : 104135.
Peng-Xiang Li; Xia-Ting Feng; Guang-Liang Feng; Ya-Xun Xiao; Bing-Rui Chen. Rockburst and microseismic characteristics around lithological interfaces under different excavation directions in deep tunnels. Engineering Geology 2019, 260, 1 .
AMA StylePeng-Xiang Li, Xia-Ting Feng, Guang-Liang Feng, Ya-Xun Xiao, Bing-Rui Chen. Rockburst and microseismic characteristics around lithological interfaces under different excavation directions in deep tunnels. Engineering Geology. 2019; 260 ():1.
Chicago/Turabian StylePeng-Xiang Li; Xia-Ting Feng; Guang-Liang Feng; Ya-Xun Xiao; Bing-Rui Chen. 2019. "Rockburst and microseismic characteristics around lithological interfaces under different excavation directions in deep tunnels." Engineering Geology 260, no. : 1.
Uncertainty in the locations where rockbursts may occur with respect to a tunnel cross-section greatly increases the difficulty in monitoring and providing warnings of rockbursts and mitigating their effects. In this paper, we analyze the characteristics of 40 rockbursts that occurred in a railway tunnel in China. The rockbursts are divided into three cases depending on their position with respect to the tunnel cross-section and the prevailing geological conditions. An in situ microseismic (MS) monitoring system was established to determine the likely position of rockbursts with respect to tunnel cross-sections. The spatiotemporal evolution of the MS events that occurred during the development of rockbursts belonging to the three cases was subsequently obtained. The mechanism responsible for the changing positions of rockbursts with respect to tunnel cross-sections was further elucidated by analyzing the fracture type of the MS events and conducting numerical simulations using three-dimensional distinct element code (3DEC). Finally, support schemes, based on the monitoring and simulation results, are suggested.
Lei Hu; Xia-Ting Feng; Ya-Xun Xiao; Rui Wang; Guang-Liang Feng; Zhi-Bin Yao; Wen-Jing Niu; Wei Zhang. Effects of structural planes on rockburst position with respect to tunnel cross-sections: a case study involving a railway tunnel in China. Bulletin of Engineering Geology and the Environment 2019, 79, 1061 -1081.
AMA StyleLei Hu, Xia-Ting Feng, Ya-Xun Xiao, Rui Wang, Guang-Liang Feng, Zhi-Bin Yao, Wen-Jing Niu, Wei Zhang. Effects of structural planes on rockburst position with respect to tunnel cross-sections: a case study involving a railway tunnel in China. Bulletin of Engineering Geology and the Environment. 2019; 79 (2):1061-1081.
Chicago/Turabian StyleLei Hu; Xia-Ting Feng; Ya-Xun Xiao; Rui Wang; Guang-Liang Feng; Zhi-Bin Yao; Wen-Jing Niu; Wei Zhang. 2019. "Effects of structural planes on rockburst position with respect to tunnel cross-sections: a case study involving a railway tunnel in China." Bulletin of Engineering Geology and the Environment 79, no. 2: 1061-1081.
Hydropower is one of the most important renewable energy sources. However, the safe construction of hydropower stations is seriously affected by disasters like rockburst, which, in turn, restricts the sustainable development of hydropower energy. In this paper, a method for rockburst prediction in the deep tunnels of hydropower stations based on the use of real-time microseismic (MS) monitoring information and an optimized probabilistic neural network (PNN) model is proposed. The model consists of the mean impact value algorithm (MIVA), the modified firefly algorithm (MFA), and PNN (MIVA-MFA-PNN model). The MIVA is used to reduce the interference from redundant information in the multiple MS parameters in the input layer of the PNN. The MFA is used to optimize the parameter smoothing factor in the PNN and reduce the error caused by artificial determination. Three improvements are made in the MFA compared to the standard firefly algorithm. The proposed rockburst prediction method is tested by 93 rockburst cases with different intensities that occurred in parts of the deep diversion and drainage tunnels of the Jinping II hydropower station, China (with a maximum depth of 2525 m). The results show that the rates of correct rockburst prediction of the test samples and learning samples are 100% and 86.75%, respectively. However, when a common PNN model combined with monitored microseismicity is used, the related rates are only 80.0% and 61.45%, respectively. The proposed method can provide a reference for rockburst prediction in MS monitored deep tunnels of hydropower projects.
Guangliang Feng; Guoqing Xia; Bingrui Chen; Yaxun Xiao; Ruichen Zhou. A Method for Rockburst Prediction in the Deep Tunnels of Hydropower Stations Based on the Monitored Microseismicity and an Optimized Probabilistic Neural Network Model. Sustainability 2019, 11, 3212 .
AMA StyleGuangliang Feng, Guoqing Xia, Bingrui Chen, Yaxun Xiao, Ruichen Zhou. A Method for Rockburst Prediction in the Deep Tunnels of Hydropower Stations Based on the Monitored Microseismicity and an Optimized Probabilistic Neural Network Model. Sustainability. 2019; 11 (11):3212.
Chicago/Turabian StyleGuangliang Feng; Guoqing Xia; Bingrui Chen; Yaxun Xiao; Ruichen Zhou. 2019. "A Method for Rockburst Prediction in the Deep Tunnels of Hydropower Stations Based on the Monitored Microseismicity and an Optimized Probabilistic Neural Network Model." Sustainability 11, no. 11: 3212.
The China Jinping Underground Laboratory phase II (CJPL-II) is currently the world’s deepest laboratory with a maximum overburden over 2.4 km. For this project, a deeply-buried shaft was constructed on the floor of the existing large-span laboratories under conditions involving high geo-stress. To explore the failure characteristics encountered and optimize the excavation and support scheme of the shaft, an in situ microseismic (MS) monitoring experiment was carried out. Firstly, an appropriate monitoring scheme was developed for this special project (i.e. the details of the sensor array required, velocity model, and system protection). Secondly, the location accuracy of the monitoring system was analyzed. On this basis, the effect of excavation and support on the fracturing processes induced in the surrounding rock was analyzed by interpreting the MS information. Thirdly, the spatial relationship between the potential damage zones and direction of the maximum principal stress was validated by analyzing the spatiotemporal evolution of the MS activity with the help of numerical simulations. In addition, some suggestions for excavation and support schemes are provided based on the monitoring results. Hence, the MS monitoring scheme and results described in this paper constitute a reference for construction design and MS monitoring of similar projects.
Lei Hu; Xia-Ting Feng; Ya-Xun Xiao; Guang-Liang Feng; Shao-Jun Li; Peng-Zhi Pan; Zhi-Bin Yao. Characteristics of the microseismicity resulting from the construction of a deeply-buried shaft. Tunnelling and Underground Space Technology 2018, 85, 114 -127.
AMA StyleLei Hu, Xia-Ting Feng, Ya-Xun Xiao, Guang-Liang Feng, Shao-Jun Li, Peng-Zhi Pan, Zhi-Bin Yao. Characteristics of the microseismicity resulting from the construction of a deeply-buried shaft. Tunnelling and Underground Space Technology. 2018; 85 ():114-127.
Chicago/Turabian StyleLei Hu; Xia-Ting Feng; Ya-Xun Xiao; Guang-Liang Feng; Shao-Jun Li; Peng-Zhi Pan; Zhi-Bin Yao. 2018. "Characteristics of the microseismicity resulting from the construction of a deeply-buried shaft." Tunnelling and Underground Space Technology 85, no. : 114-127.
Rockbursts cause serious casualties and damage in deep, hard rock tunnels. Structural planes can play an important role in the rockburst development process. In this paper, effects of structural planes on the microseismicity in rockburst development processes are summarized and studied in deep tunnels of the Jinping-II Hydropower Station, China. The study is based on an analysis of 44 moderate and intense rockbursts which occurred during a period of more than a year of microseismic (MS) monitoring and relates to 11.6 km of tunneling. The results show that most of the cases are affected by structural planes regardless of the rockburst’s moderate or intense character. The structural planes in the areas where rockbursts occur are mostly stiff ones and grade III or IV ones. In rockbursts development processes affected by structural planes, the MS energy proportion of big MS events, i.e. whose logarithm of MS energy (measured in Joules) is larger than 3.83, is comparatively lower. Structural planes change the way microseismicity evolves. Right from the beginning in the rockburst development and just before the rockburst affected by structural planes, there were some big MS events occurring. And structural planes cause rockbursts to occur more likely. Threshold values of the microseismicity (number of MS events and MS energy) for rockburst occurrence are relatively lower. In addition, the microseismicity in rockburst development processes with different intensities and with/without structural planes shows discreteness and the microseismicity is greater in more intense rockbursts.
Guang-Liang Feng; Xia-Ting Feng; Bing-Rui Chen; Ya-Xun Xiao; Zhou-Neng Zhao. Effects of structural planes on the microseismicity associated with rockburst development processes in deep tunnels of the Jinping-II Hydropower Station, China. Tunnelling and Underground Space Technology 2018, 84, 273 -280.
AMA StyleGuang-Liang Feng, Xia-Ting Feng, Bing-Rui Chen, Ya-Xun Xiao, Zhou-Neng Zhao. Effects of structural planes on the microseismicity associated with rockburst development processes in deep tunnels of the Jinping-II Hydropower Station, China. Tunnelling and Underground Space Technology. 2018; 84 ():273-280.
Chicago/Turabian StyleGuang-Liang Feng; Xia-Ting Feng; Bing-Rui Chen; Ya-Xun Xiao; Zhou-Neng Zhao. 2018. "Effects of structural planes on the microseismicity associated with rockburst development processes in deep tunnels of the Jinping-II Hydropower Station, China." Tunnelling and Underground Space Technology 84, no. : 273-280.
In this study, true triaxial compression tests were carried out on three types of hard rocks (i.e., granite, marble and sandstone) using rectangular prismatic specimens (50 × 50 × 100 mm3) with low minimum principal stress σ3, and various intermediate principal stresses σ2. The main purposes were to establish the relationship between the characteristic stress levels (i.e., crack initiation stress, crack damage stress and peak stress) and the corresponding principal stresses and to investigate the brittle fracturing process of hard rocks near excavation boundaries. The test results indicated that the stress–strain curves were primarily characterized by the linear-elastic–brittle behavior. The failure planes of the specimens in the tests were found to be adjacent to the σ3 loading surface, and almost parallel to the σ1–σ2 plane, which were analogous to the spalling of the surrounding rock. With the aid of scanning electron microscopy, it was shown that cleavage fractures accounted for the majority of the fracture morphology in the sandstone specimens. Two revised methods were developed to determine the crack initiation stress of hard rocks under true triaxial compression, and these characteristic stress levels could be appropriately fitted by utilizing both the parabolic and power functions. Although the power function achieved better fitting results, the parameters in the parabolic function could be associated with the tensile cracks induced during the loading process. The influence of intermediate principal stress on the strength, deformation and failure was significant. In addition, the brittle fracturing process could be illustrated by the crack-induced strains in three principal stress directions.
Yao-Hui Gao; Xia-Ting Feng; Xi-Wei Zhang; Guang-Liang Feng; Quan Jiang; Shi-Li Qiu. Characteristic Stress Levels and Brittle Fracturing of Hard Rocks Subjected to True Triaxial Compression with Low Minimum Principal Stress. Rock Mechanics and Rock Engineering 2018, 51, 3681 -3697.
AMA StyleYao-Hui Gao, Xia-Ting Feng, Xi-Wei Zhang, Guang-Liang Feng, Quan Jiang, Shi-Li Qiu. Characteristic Stress Levels and Brittle Fracturing of Hard Rocks Subjected to True Triaxial Compression with Low Minimum Principal Stress. Rock Mechanics and Rock Engineering. 2018; 51 (12):3681-3697.
Chicago/Turabian StyleYao-Hui Gao; Xia-Ting Feng; Xi-Wei Zhang; Guang-Liang Feng; Quan Jiang; Shi-Li Qiu. 2018. "Characteristic Stress Levels and Brittle Fracturing of Hard Rocks Subjected to True Triaxial Compression with Low Minimum Principal Stress." Rock Mechanics and Rock Engineering 51, no. 12: 3681-3697.
Ya-Xun Xiao; Xia-Ting Feng; Bing-Rui Chen; Guang-Liang Feng. Microseismic Monitoring Method of the Rockburst Evolution Process. Rockburst 2018, 301 -315.
AMA StyleYa-Xun Xiao, Xia-Ting Feng, Bing-Rui Chen, Guang-Liang Feng. Microseismic Monitoring Method of the Rockburst Evolution Process. Rockburst. 2018; ():301-315.
Chicago/Turabian StyleYa-Xun Xiao; Xia-Ting Feng; Bing-Rui Chen; Guang-Liang Feng. 2018. "Microseismic Monitoring Method of the Rockburst Evolution Process." Rockburst , no. : 301-315.
Rockbursts occur frequently and cause serious damage in deep tunnels. Microseismic (MS) source location is of great importance and forms the foundation of the MS monitoring technology used in tunnel rockburst hazard mechanism analysis. A highly accurate method for locating MS events that occur during rockburst development in tunnels is proposed here. An anisotropic velocity model, rockburst event monitor, and a global optimization algorithm (particle swarm optimization) are used in tandem to make the proposed method feasible and the location accuracy better. Simulation results show the MS sources can be located more accurately using the proposed method. The average location error is reduced by 20.16 m. Our method was used to locate MS events associated with rockburst development processes occurring in the deep tunnels of the Jinping II hydropower station in China. The location accuracy of the MS events in the rockburst development process is significantly improved. The case study shows that the located MS events are clustered together more closely in the rockburst area. The average distance of all the MS events to the position of the rockburst is reduced from 23.77 to 13.43 m. The method is highly conducive to in-depth analysis of rockburst development processes and investigation of their mechanisms of formation.
G. L. Feng; X. T. Feng; B. R. Chen; Y. X. Xiao. A Highly Accurate Method of Locating Microseismic Events Associated With Rockburst Development Processes in Tunnels. IEEE Access 2017, 5, 27722 -27731.
AMA StyleG. L. Feng, X. T. Feng, B. R. Chen, Y. X. Xiao. A Highly Accurate Method of Locating Microseismic Events Associated With Rockburst Development Processes in Tunnels. IEEE Access. 2017; 5 ():27722-27731.
Chicago/Turabian StyleG. L. Feng; X. T. Feng; B. R. Chen; Y. X. Xiao. 2017. "A Highly Accurate Method of Locating Microseismic Events Associated With Rockburst Development Processes in Tunnels." IEEE Access 5, no. : 27722-27731.
Ya-Xun Xiao; Xia-Ting Feng; Bing-Rui Chen; Guang-Liang Feng; Zhi-Bin Yao; Lian-Xing Hu. Excavation-induced microseismicity in the columnar jointed basalt of an underground hydropower station. International Journal of Rock Mechanics and Mining Sciences 2017, 97, 99 -109.
AMA StyleYa-Xun Xiao, Xia-Ting Feng, Bing-Rui Chen, Guang-Liang Feng, Zhi-Bin Yao, Lian-Xing Hu. Excavation-induced microseismicity in the columnar jointed basalt of an underground hydropower station. International Journal of Rock Mechanics and Mining Sciences. 2017; 97 ():99-109.
Chicago/Turabian StyleYa-Xun Xiao; Xia-Ting Feng; Bing-Rui Chen; Guang-Liang Feng; Zhi-Bin Yao; Lian-Xing Hu. 2017. "Excavation-induced microseismicity in the columnar jointed basalt of an underground hydropower station." International Journal of Rock Mechanics and Mining Sciences 97, no. : 99-109.
This paper reviews the recent achievements made by our team in the mitigation of rockburst risk. It includes the development of neural network modeling on rockburst risk assessment for deep gold mines in South Africa, an intelligent microseismicity monitoring system and sensors, an understanding of the rockburst evolution process using laboratory and in situ tests and monitoring, the establishment of a quantitative warning method for the location and intensities of different types of rockburst, and the development of measures for the dynamic control of rockburst. The mitigation of rockburst at the Hongtoushan copper mine is presented as an illustrative example
Xia-Ting Feng; Jianpo Liu; Bingrui Chen; Yaxun Xiao; Guang-Liang Feng; Fengpeng Zhang. Monitoring, Warning, and Control of Rockburst in Deep Metal Mines. Engineering 2017, 3, 538 -545.
AMA StyleXia-Ting Feng, Jianpo Liu, Bingrui Chen, Yaxun Xiao, Guang-Liang Feng, Fengpeng Zhang. Monitoring, Warning, and Control of Rockburst in Deep Metal Mines. Engineering. 2017; 3 (4):538-545.
Chicago/Turabian StyleXia-Ting Feng; Jianpo Liu; Bingrui Chen; Yaxun Xiao; Guang-Liang Feng; Fengpeng Zhang. 2017. "Monitoring, Warning, and Control of Rockburst in Deep Metal Mines." Engineering 3, no. 4: 538-545.
Guang-Liang Feng; Xia-Ting Feng; Bing-Rui Chen; Ya-Xun Xiao. Performance and feasibility analysis of two microseismic location methods used in tunnel engineering. Tunnelling and Underground Space Technology 2017, 63, 183 -193.
AMA StyleGuang-Liang Feng, Xia-Ting Feng, Bing-Rui Chen, Ya-Xun Xiao. Performance and feasibility analysis of two microseismic location methods used in tunnel engineering. Tunnelling and Underground Space Technology. 2017; 63 ():183-193.
Chicago/Turabian StyleGuang-Liang Feng; Xia-Ting Feng; Bing-Rui Chen; Ya-Xun Xiao. 2017. "Performance and feasibility analysis of two microseismic location methods used in tunnel engineering." Tunnelling and Underground Space Technology 63, no. : 183-193.