Microseismic Monitoring of Rock Mass Fracture Response to Blasting Excavation of Large Underground Caverns Under High Geostress

2021 ◽  
Author(s):  
Jin-Shuai Zhao ◽  
Bing-Rui Chen ◽  
Quan Jiang ◽  
Jian-Fei Lu ◽  
Xian-Jie Hao ◽  
...  
Keyword(s):  
Rock Mass ◽  
Microseismic Monitoring ◽  
Underground Caverns ◽  
Blasting Excavation ◽  
High Geostress

scholarly journals Numerical Simulation of Blast Vibration and Crack Forming Effect of Rock-Anchored Beam Excavation in Deep Underground Caverns

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
XinPing Li ◽  
JunHong Huang ◽  
Yi Luo ◽  
Qian Dong ◽  
YouHua Li ◽  
...  
Keyword(s):  
Rock Mass ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Finite Element Software ◽  
Underground Cavern ◽  
Underground Caverns ◽  
Blasting Excavation

Aiming at surrounding rock damage induced by dynamic disturbance from blasting excavation of rock-anchored beam in rock mass at moderate or far distance in underground cavern, numerical model of different linear charging density and crustal stress in underground cavern is established by adopting dynamic finite element software based on borehole layout, charging, and rock parameter of the actual situation of a certain hydropower station. Through comparison in vibration velocity, contour surface of rock mass excavation, and the crushing extent of excavated rock mass between calculation result and field monitoring, optimum linear charging density of blast hole is determined. Studies are also conducted on rock mass vibration in moderate or far distance to blasting source, the damage of surrounding rock in near-field to blasting source, and crushing degree of excavated rock mass under various in situ stress conditions. Results indicate that, within certain range of in situ stress, the blasting vibration is independent of in situ stress, while when in situ stress is increasing above certain value, the blasting vibration velocity will be increasing and the damage of surrounding rock and the crushing degree of excavated rock mass will be decreasing.

scholarly journals Stability Evaluation on Surrounding Rocks of Underground Powerhouse Based on Microseismic Monitoring

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Feng Dai ◽  
Biao Li ◽  
Nuwen Xu ◽  
Yongguo Zhu ◽  
Peiwei Xiao
Keyword(s):  
Rock Mass ◽  
Microseismic Monitoring ◽  
Surrounding Rock ◽  
Underground Powerhouse ◽  
Multiple Faults ◽  
Routine Monitoring ◽  
Underground Caverns ◽  
Macroscopic Deformation ◽  
Microseismic Events ◽  
The Stability

To study the stability of underground powerhouse at Houziyan hydropower station during excavation, a microseismic monitoring system is adopted. Based on the space-time distribution characteristics of microseismic events during excavation of the main powerhouse, the correlation between microseismic events and blasting construction is established; and the microseismic clustering areas of the underground powerhouse are identified and delineated. The FLAC3D code is used to simulate the deformation of main powerhouse. The simulated deformation characteristics are consistent with that recorded by microseismic monitoring. Finally, the correlation between the macroscopic deformation of surrounding rock mass and microseismic activities is also revealed. The results show that multiple faults between 1# and 3# bus tunnels are activated during excavation of floors V and VI of the main powerhouse. The comprehensive method combining microseismic monitoring with numerical simulation as well as routine monitoring can provide an effective way to evaluate the surrounding rock mass stability of underground caverns.

Influence Research of Underground Caverns Blasting Excavation on Excavation Damage Zone of Adjacent Cavern

2013 ◽  
Vol 838-841 ◽  
pp. 901-906 ◽  
Author(s):  
Peng Cheng Xu ◽  
Qian Dong ◽  
Xin Ping Li ◽  
Yi Luo
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Kinematic Hardening ◽  
Damage Zone ◽  
Side Wall ◽  
Measured Data ◽  
Excavation Damage Zone ◽  
Underground Caverns ◽  
Blasting Excavation ◽  
Excavation Damage

The influence of the single cavern blasting excavation in underground caverns on the stability of surrounding rock of adjacent caverns can not be ignored.In–situ blasting vibration test and dynamic finite element analysis were used to study the laws of blasting seismic wave propagation, two different material constitutive models were adopted, compared with measured data,to select material constitutive model which was more in line with the dynamic characteristics of rock mass in underground caverns.On this basis, the influence mechanism for blast–induced EDZ(Excavation Damage Zone) of the adjacent cavern is studied through the method of numerical simulation. The results show that the numerical simulation resulted by adopting kinematic hardening model were more close to measured data than adopting ideal elastic–plastic model; the middle part of adjacent tunnel side wall facing blasting had the largest damaged rock mass range; both sides of the arch and the foundation rock of the adjacent cavern emerged damaged rock mass area, and the area of adjacent tunnel side wall facing blasting was larger than side wall not facing blasting.

Study on Deformation and Damage of Rock Mass Subject to High In Situ Stress by Using a Elastoplastic Damage Model and Considering the Impact of Weak Planes

2013 ◽  
Vol 838-841 ◽  
pp. 705-709
Author(s):  
Yun Hao Yang ◽  
Ren Kun Wang
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Damage Model ◽  
Back Analysis ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
High In Situ Stress ◽  
Underground Caverns ◽  
The Impact

Large scale underground caverns are under construction in high in-situ stress field at Houziyan hydropower station. To investigate deformation and damage of surrounding rock mass, a elastoplastic orthotropic damage model capable of describing induced orthotropic damage and post-peak behavior of hard rock is used, together with a effective approach accounting for the presence of weak planes. Then a displacement based back analysis was conducted by using the measured deformation data from extensometers. The computed displacements are in good agreement with the measured ones at most of measurement points, which confirm the validities of constitutive model and numerical simulation model. The result of simulation shows that damage of surrounding rock mass is mainly dominated by the high in-situ stress rather than the weak planes and heavy damage occur at the cavern shoulders and side walls.

scholarly journals Numerical Simulation on Large Deformation of Weak Rock Mass Tunnel Under High Geostress

2018 ◽  
Vol 175 ◽  
pp. 03025
Author(s):  
Feng Zhou ◽  
Hongjian Jiang ◽  
Xiaorui Wang
Keyword(s):  
Rock Mass ◽  
Large Deformation ◽  
Lateral Pressure ◽  
Simulation Analysis ◽  
Pressure Coefficient ◽  
Surrounding Rock ◽  
Analog Simulation ◽  
Lateral Pressure Coefficient ◽  
High Geostress ◽  
The Stability

The problem about the stability of tunnel surrounding rock is always an important research object of geotechnical engineering, and the right or wrong of the result from stability analysis on surrounding rock is related to success or failure of an underground project. In order to study the deformation rules of weak surrounding rock along with lateral pressure coefficient and burying depth varying under high geostress and discuss the dynamic variation trend of surrounding rock, the paper based on the application of finite difference software of FLAC3D, which can describe large deformation character of rock mass, analog simulation analysis of surrounding rock typical section of the class II was proceeded. Some conclusions were drawn as follows: (1) when burying depth is invariable, the displacements of tunnel surrounding rock have a trend of increasing first and then decreasing along with increasing of lateral pressure coefficient. The floor heave is the most sensitive to change of lateral pressure coefficient. The horizontal convergence takes second place. The vault subsidence is feeblish to change of lateral pressure coefficient. (2) The displacements of tunnel surrounding rock have some extend increase along with increasing of burying depth. The research conclusions are very effective in analyzing the stability of surrounding rock of Yunling tunnel. These are going to be a reference to tunnel supporting design and construction.

scholarly journals Research on Deformation Mechanisms of a High Geostress Soft Rock Roadway and Double-Shell Grouting Technology

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Fengnian Wang ◽  
Shizhuang Chen ◽  
Pan Gao ◽  
Zhibiao Guo ◽  
Zhigang Tao
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Large Deformation ◽  
Coal Mine ◽  
Soft Rock ◽  
In Situ Stress ◽  
Deformation Monitoring ◽  
Deformation And Failure ◽  
Working Face ◽  
High Geostress

In this study, the deformation characteristics and mechanical properties of coal and rock mass in the S2N5 working face of the Xiaokang coal mine are analyzed to address the problem of large deformation of soft rocks with high in situ stress surrounding roadways. Through a newly developed grouting pipe, a double-shell grouting technology, consisting of low-pressure grouting and high-pressure split grouting, is proposed for the Xiaokang coal mine. In addition, the effect of grouting is evaluated by borehole peeping and deformation monitoring. The results show that the double-shell grouting technology can effectively improve the overall mechanical properties of the surrounding coal and rock mass, preventing the large deformation and failure of the roadway. This technology can be useful when analyzing and preventing large deformation of soft rock roadways.

scholarly journals Automatic Classification of Microseismic Signals Based on MFCC and GMM-HMM in Underground Mines

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Pingan Peng ◽  
Zhengxiang He ◽  
Liguan Wang
Keyword(s):  
Rock Mass ◽  
Gaussian Mixture ◽  
Automatic Classification ◽  
Microseismic Monitoring ◽  
Underground Mines ◽  
Basic Step ◽  
Microseismic Data ◽  
Safety Risks ◽  
Microseismic Events

In order to mitigate economic and safety risks during mine life, a microseismic monitoring system is installed in a number of underground mines. The basic step for successfully analyzing those microseismic data is the correct detection of various event types, especially the rock mass rupture events. The visual scanning process is a time-consuming task and requires experience. Therefore, here we present a new method for automatic classification of microseismic signals based on the Gaussian Mixture Model-Hidden Markov Model (GMM-HMM) by using only Mel-frequency cepstral coefficient (MFCC) features extracted from the waveform. The detailed implementation of our proposed method is described. The performance of this method is tested by its application to microseismic events selected from the Dongguashan Copper Mine (China). A dataset that contains a representative set of different microseismic events including rock mass rupture, blasting vibration, mechanical drilling, and electromagnetic noise is collected for training and testing. The results show that our proposed method obtains an accuracy of 92.46%, which demonstrates the effectiveness of the method for automatic classification of microseismic data in underground mines.

scholarly journals Research on the Layered Rock Mass Excavation Relaxation Stability of Underground Caverns

2020 ◽  
Vol 165 ◽  
pp. 03024
Author(s):  
Ying Zhang ◽  
Heng Zhou ◽  
Shengjie Di ◽  
Xi Lu
Keyword(s):  
Rock Mass ◽  
Mechanical Characteristics ◽  
Generation System ◽  
Yield Zone ◽  
Layered Rock ◽  
Underground Caverns ◽  
Structure Surface ◽  
Layered Rock Mass ◽  
Power Generation System ◽  
The Stability

In order to compare the influence of rock mass parameters weakening on the deformation and stability of excavation caverns in layered rock mass, based on power generation system caverns of a hydropower station, the stability and deformation of the caverns is analyzed. The results show that the mechanical characteristics of the structure surface play a major role in controlling the stability of caverns. And the displacement and yield zone value of plan 3, which adopt elastic-plastic softening model, are significantly larger than other two. The method which consider the residual strength of structure surface is more suitable for the excavation calculation of layered rock mass cavern.

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