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Journal of Intelligent Construction 2025年第3期1卷 1-15页

作者： Peng Zhang nuwen xu Peiwei Xia Tao Zhao Furong Gao Xinchao Ding Biao Li State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and Hydropower Sichuan University Chengdu China CHN Energy Jinsha River Xulong Hydropower Co. Ltd. China Department of Civil and Environmental Engineering Brunel University London UK PowerChina Northwest Engineering Co. Ltd. Xi'an China School of Geoscience and Technology Southwest Petroleum University Chengdu China

Highly accurate microseismic (MS) localization is the basis for rock damage assessment and disaster warning. The engineering background noise mixed in the MS signal $(s(\varepsilon))$ seriously affects the subsequent analysis of the MS signal. A noise reduction method of singular spectral analysis-complementary ensemble empirical mode decomposition-wavelet threshold (SSA-CEEMD-WT) is proposed. The CEEMD, CEEMD-WT, and proposed methods are used for denoising the noisy Ricker wavelet. The signal-to-noise ratio (SNR) of the denoised signal $(x_{\text{de}}(\varepsilon))$ by the proposed method is 56.77% and 37.88% higher than those of CEEMD and CEEMD-WT methods, respectively. Moreover, an adaptive artificial bee colony (ABC) algorithm is applied for MS source $(O(h_{0},\ y_{0},\ z_{0}))$ location. The time to quantile difference is introduced as the objective function. The blast positioning test results prove that the proposed method improves the positioning accuracy of particle swarm optimization (PSO) algorithm and simulated annealing PSO (SA-PSO) algorithm by 44.12% and 47.64%, respectively. The MS positions of underground caverns reveal that the calculated clusters of MS events using the adaptive ABC algorithm are more concentrated at the structural plane and appearance deformation failure location and in good agreement with field survey and routine monitoring data.

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Microseismic moment tensor based analysis of rock mass failure mechanism surrounding an underground powerhouse

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GEOMATICS NATURAL HAZARDS & RISK 2021年第1期12卷 1315-1342页

作者： Sun, Yuepeng Li, Biao Dong, Linlu Mao, Haoyu xu, nuwen Zhu, Zhongping Liu, Jinfei Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu Sichuan Peoples R China Southwest Petr Univ Sch Geosci & Technol Chengdu Sichuan Peoples R China Sichuan Dadu River Shuangjiangkou Hydropower Dev Maerkang Peoples R China Power China Chengdu Engn Co Ltd Chengdu Peoples R China

The failure mechanism of surrounding rock is an important issue in the field of underground engineering. To quantitatively understand the failure process and failure mechanism of the surrounding rock mass in deep underground engineering, the underground powerhouse of the Houziyan hydropower station was selected as a case study. The study area was determined by analysing the spatiotemporal distribution of microseismic (MS) events and site investigations. After noise reduction, P-wave arrival time extraction and positioning of MS signals, the moment tensor inversion method was used to determine the failure mechanism and fracture direction of the surrounding rock mass. The results showed that (1) the failure processes and mechanism of the surrounding rock mass can be effectively analysed through MS monitoring with moment tensor analysis and (2) the failure type of the surrounding rock mass downstream of the main powerhouse was characterized by shear failure. The stress state in this region was a strike-slip stress state. (3) The failure type of the surrounding rock mass at the arch roof of the main transformer chamber was characterized by tensile failure. The tensile stress of the intermediate stress axis was obvious, and the tectonic stress presented a state of near uniaxial compression-biaxial tension.

关键词： underground caverns MS monitoring high ground stress moment tensor inversion failure mechanism

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Comprehensive analysis of the surrounding rock mass stability in the underground caverns of Jinping I hydropower station in Southwest China

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TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 2020年 104卷

作者： Ma, Ke Zhang, Jianhai Zhou, Zhong xu, nuwen Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian 116024 Liaoning Peoples R China Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Sichuan Peoples R China PowerChina Chengdu Engn Corp Ltd Chengdu 610072 Sichuan Peoples R China

The geological conditions of the underground caverns in the Jinping I hydropower station are particularly complicated, with high ground stress (the extreme value of the measuring point is 35.7 MPa), complicated deformation and failure mechanisms, and large unloading depth. The large deformation of the surrounding rock mass was beyond current engineering and academic understanding. During the construction period, the deformation and failure mechanisms were complex, and the unloading depth was large. The maximum deformation of the sidewall of the main powerhouse reached 246 mm. The monitoring results of multi-point extensometers basically converged two years after the completion of cavern excavation. Regarding the deformation and failure mechanism of the large underground caverns, the energy dissipation theory that can better describe the complex mechanical response analysis was proposed. The deformation failure mechanism, mechanical behaviour, supporting effect and stability evaluation of the large underground caverns were investigated from the perspectives of excavation unloading and energy dissipation and release. The excavation unloading-induced relaxation characteristics of the surrounding rock mass were analysed using a comprehensive approach incorporating the results of borehole television, acoustic wave testing, multipoint extensometer and numerical simulations. A criterion of the surrounding rock mass delineation incorporating the energy dissipation ratio, acoustic wave testing, wave velocity variation and elastic modulus variation was also proposed. Furthermore, the phenomena and law of deformation and failure of surrounding rock mass in the large underground caverns were revealed. The stability of surrounding rock mass in the underground caverns was evaluated. The related achievements can provide some references for similar deep underground rock engineering.

关键词： Energy dissipation theory Numerical simulation Failure mechanism Underground cavern Jinping I hydropower station

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Stability Analysis of the Arch Crown of a Large-Scale Underground Powerhouse During Excavation

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ROCK MECHANICS AND ROCK ENGINEERING 2020年第6期53卷 2935-2943页

作者： Hu, Zhonghua xu, nuwen Li, Biao xu, Ying xu, Jian Wang, Kai Tianjin Univ Sch Civil Engn Tianjin 300350 Peoples R China Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Sichuan Peoples R China Southwest Petr Univ Sch Geosci & Technol Chengdu 610500 Sichuan Peoples R China China Three Gorges Projects Dev Co Ltd Beijing 100038 Peoples R China China Yangtze Power Co Ltd Yichang 443002 Hubei Peoples R China

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An Improved Creep Model for Granite Based on the Deviatoric Stress-to-Peak Strength Ratio

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ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2021年第5期46卷 5157-5170页

作者： Qian, Li Zhang, Jianhai Wang, Xianliang Li, Yonghong Zhang, Ru xu, nuwen Li, Zhiguo Sichuan Univ Coll Water Resources & Hydropower State Key Lab Hydraul & Mt River Engn Chengdu 610065 Peoples R China Power China Chengdu Engn Corp Ltd Chengdu 610072 Peoples R China

Time-dependent behaviors of rocks can be attributed to long-term applied stress, which occurs in most underground engineering projects. The creep behavior of granite from the Shuangjiangkou underground powerhouse in western Sichuan Province, China, was investigated via creep tests. It is shown that granite has an obvious creep behavior under different confining pressures and deviatoric stresses. The new dimensionless parameter DPR, which is defined as the ratio of the deviatoric stress to the peak strength, is proposed for experimental analysis. The relationships between the instantaneous strain and final visco-elastic creep strain of granite with DPR are established under different confining pressures. It is shown that when DPR is equal to 0.63, the final visco-elastic creep strain of rocks will reach a minimum value. Based on DPR and the secondary creep strain rate, a unified method for defining the long-term strength of rocks is proposed, and the granite will enter in secondary creep with a nonzero strain rate when DPR > 0.9501. The Nishihara model is improved, and the relationships between the parameters of the improved model with confining pressures and DPR are obtained. The improved creep model can satisfactorily represent the primary creep strain of granite and secondary creep strain of granite with time under a given confining pressure and deviatoric stress.

关键词： Deviatoric stress-to-peak strength ratio Final visco-elastic creep strain Strain curves Long-term strength Improved Nishihara model

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Characterizing rockbursts and analysis on frequency-spectrum evolutionary law of rockburst precursor based on microseismic monitoring

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TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 2020年 105卷

作者： Liang, Zhengzhao xue, Ruixiong xu, nuwen Li, Wanrun Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian 116024 Liaoning Peoples R China Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Sichuan Peoples R China

The access tunnel in the main powerhouse of the Shuangjiangkou hydropower station in China has complex geological conditions with high in-situ stress. Rockbursts pose serious threats to the safety of personnel and equipment in the tunnel. Three-dimensional microseismic (MS) monitoring technology was used to explore MS activities inside the tunnel surrounding rock. In consideration of various kinds of signals, the Fast Fourier Transform (FFT) method was employed to obtain the amplitude-frequency spectra of signal waveforms, and then, some waveform characteristics (amplitude, duration, dominant frequency distribution range, peak frequency, main frequency value, etc.) were analyzed to recognize MS signals. It provided a guarantee for further analysis of signals, and also provided significant guidance for MS signal recognition in other tunnels. Based on MS activity frequency and released energy time-series curves, the rockburst sequence type in the tunnel can be determined as foreshock-mainshock-aftershock. Studying spatiotemporal distribution characteristics of microcracks inside the surrounding rock, dominant active areas inside the surrounding rock of the tunnel have been delimited. In addition, a more efficient signal analysis technique (wavelet packet transform) was used to frequency-decompose complex MS waveforms and the dominant information of signals was retained;furthermore, a time-frequency model was first established to analyze the activity characteristics inside the surrounding rock;by using the model we can more intuitively analyze and accurately judge rockburst precursor information. The results indicated that a downward shift phenomenon of frequency band energy distribution can be used as an early warning indicator of rockbursts.

关键词： Microseismic monitoring Fast Fourier Transform Wavelet packet transform Rockburst Early warning

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

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INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES 2021年 142卷

作者： xue, Ruixiong Liang, Zhengzhao xu, nuwen Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian 116024 Liaoning Peoples R China Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Sichuan Peoples R China

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.

关键词： Rockburst Microseismic monitoring Apparent stress Apparent volume Main frequency Numerical simulation

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Microseismic monitoring and stability analysis for the large-scale underground caverns at the Wudongde hydropower station

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BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT 2020年第7期79卷 3559-3573页

作者： Li, Biao xu, nuwen Dai, Feng Gu, Gongkai Ke, Wei Southwest Petr Univ Sch Geosci & Technol Chengdu 610500 Sichuan Peoples R China Sichuan Univ Coll Water Resource & Hydropower State Key Lab Hydraul & Mt River Engn Chengdu 610065 Sichuan Peoples R China China Three Gorges Projects Dev Co Ltd Beijing 100038 Peoples R China

To analyse the stability of rock mass subjected to excavation of the underground caverns at the Wudongde hydropower station, a high-resolution microseismic (MS) monitoring system was applied. Based on the temporal evolution characteristics of MS events, the relationship between construction state and MS activity was established. Combining the spatial evolution characteristics of MS events with traditional monitoring, geological survey and field observation, several main damage regions were identified and the key factors causing rock mass damage were revealed. Furthermore, the evolution laws of MS source multi-parameters during the large deformation of rock mass were systemically analysed. Prior to the large deformation of rock mass, the MS source multi-parameters behaved differently, including an obvious increment of the number of MS events, a sharp increment of the energy index with a progressive increment of the apparent volume and a decreasing trend of the centre frequency. The present study reveals that the integrated analytical method incorporating MS monitoring, traditional monitoring, geological survey and field observation leads to a better understanding of the behaviour of surrounding rock mass subjected to excavation, which is of great significance for the risk management of rock mass deformation and failures in the large-scale underground caverns.

关键词： Microseismic monitoring Stability analysis Underground powerhouse Excavation Wudongde hydropower station

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Failure Mechanism and Deformation Forecasting of Surrounding Rock Mass in an Underground Cavern Based on Engineering Analogy Method

SSRN

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SSRN 2023年

作者： Mao, Haoyu xu, nuwen Zhou, Zhong Sha, Chun Xiao, Peiwei Li, Biao State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and Hydropower Sichuan University Sichuan Province Chengdu610065 China PowerChina Chengdu Engineering Corporation Limited Sichuan Province Chengdu610072 China School of Geoscience and Technology Southwest Petroleum University Sichuan Province Chengdu610500 China

The underground powerhouse of Lianghekou hydropower station is deeply buried with high ground stress and complicated geological conditions. To delineate rock mass damage zones and analyze the stability of underground powerhouse subjected to excavation disturbance, an ESG monitoring system was applied to carry out real-time monitoring against the inner micro-fracture activity of surrounding rock mass. In order to solve the problem that the deformation of surrounding rock mass cannot be monitored due to the failure of multipoint displacement meters, the engineering analogy method is adopted to forecast the deformation of surrounding rock mass by comparing the similar projects of Houziyan and Baihetan hydropower stations. Research results show: (1) The failure of surrounding rock mass was stress-driven failure, and was primarily characterized by a medium degree of stress-induced failure. (2) During the monitoring period, microseismic (MS) events clustering area formed, which was both related to blasting excavation disturbance of the bus tunnel and the formed crossed free surfaces. (3) The seismic source parameters during the deformation of surrounding rock mass in similar projects were analyzed, and the variation characteristics of the frequency, energy, b-value, central frequency, apparent stress, and apparent volume of MS events were summarized. (4) The engineering analogy method was adopted to forecast that the deformation period of surrounding rock mass of Lianghekou hydropower station is from April 25 to May 2, 2016. The present achievements can provide some references for similar deep underground excavation engineering. © 2023, The Authors. All rights reserved.

关键词： Forecasting

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Analysis on microseismic characteristics and stability of the access tunnel in the main powerhouse, Shuangjiangkou hydropower station, under high in situ stress

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BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT 2020年第6期79卷 3231-3244页

作者： Liang, Zhengzhao xue, Ruixiong xu, nuwen Dong, Linlu Zhang, Yinghao Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian 116024 Peoples R China Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Sichuan Peoples R China China Gezhouba Grp 1 Engn Co Ltd Yichang 443002 Peoples R China

Access tunnel in the main powerhouse of Shuangjiangkou hydropower station was deep buried with high in situ stress and complex geological conditions. Microseismic monitoring technology was established to monitor microcrack evolution process inside the surrounding rock in early excavation stage. Serious falling blocks in the left spandrel of the tunnel were predicted in a timely manner by delimiting major damage areas in the tunnel. Based on comparative analysis on microseismic activity law and field failure characteristics of the access tunnel, a quantitative index was supposed between slight rockburst like falling blocks and microseismic events. Moreover, the change law of daily average apparent stress difference and b value were analyzed based on microseismic event data. In addition, a three-dimensional numerical simulation software (RFPA3D) was used to simulate the damage distribution around the tunnel, and a relationship between spatial position of tunnel damage and direction of the maximum principal stress was qualitatively analyzed. The study results showed that advance speed of the tunnel working face was an important factor affecting the state of stress redistribution in surrounding rock mass, and the change law of b values of microseismic events could be used to predict activity state inside the surrounding rock effectively, which reflected mechanical properties and stress state of surrounding rock. In particular, field falling blocks became more serious with increasing b value, and field surrounding rock was relatively stable with minor b value. A risk of surrounding rock instability was relatively high with small b values. It provided an efficient method of predicting and assessing slight rockburst like falling blocks. The study results can provide significant guidance for field construction and later construction planning.

关键词： High in situ stress Microseismic monitoring b value Apparent stress Numerical simulation

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