Stability Analysis of Surrounding Rock Mass of Underground Powerhouse Cavern

2013 ◽  
Vol 838-841 ◽  
pp. 878-882
Author(s):  
Xiao Gang He ◽  
Feng Dai ◽  
Nu Wen Xu ◽  
Chun Sha
Keyword(s):  
Surrounding Rock ◽  
Seismic Events ◽  
Distribution Characteristic ◽  
Lagrangian Analysis ◽  
Underground Powerhouse ◽  
Underground Caverns ◽  
Calculation Results ◽  
Microseismic Events ◽  
Plastic Zones ◽  
Distribution Of Stress

The underground powerhouse of Houziyan hydropower station has some typical characteristics such as high strata stress, large span and high sidewalls. In this paper, numerical simulation of continuous excavation and support of the underground caverns was performed using the Fast Lagrangian Analysis of Continuum method (FLAC3D). Then, the distribution characteristic of the deformation field, stress field and plastic zones was analyzed based on the numerical calculation results. In addition, the distribution of stress was compared with microseismic events. It shows that stress concentration can cause micro-seismic events regional aggregation.

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.

Analysis on Causes of Deformation and Failure of Large Scale Underground Powerhouse

2011 ◽  
Vol 71-78 ◽  
pp. 644-650 ◽  
Author(s):  
Jin Yu Dong ◽  
Ji Hong Yang ◽  
Guo Xiang Yang ◽  
Fa Quan Wu
Keyword(s):  
Large Scale ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Concrete Cracking ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Underground Caverns ◽  
Geological Conditions ◽  
The Right

Jinoping No.1 is a dominant reservoir cascade hydropower station which locates at the downstream of Yalong river. The underground powerhouse locates at the right bank of the dam, lithology is marble that belongs to the second member of Zagunao group. It is constructed at region with very complicated geological conditions and high geo-stress. Concrete cracking, spalling and steel buckling and bending occurred at the downstream crown after supporting. This paper analysed the causes of deformation and failure through geological analysis and numerical simulation, and concluded that deformation and failure mainly occurred at the region where the quality of surrounding rock belongs to Ⅲ1 and had nothing to do with the unstable block cut by cracks; stress field of surrounding rock varied continueously with the proceeding of successive excavation of underground powerhouse, so the compressive stress and shear stress concentration occurred which caused the compression and shear failure of downstream crown and made it bending to the free face. It is significant to the further enforcement of this project and to the research on other similar underground caverns theoretically and practically.

Effect of Abutment Load of Arch Dam on Stability of Underground Caverns Complex

2014 ◽  
Vol 501-504 ◽  
pp. 2045-2048
Author(s):  
Cun Hui Zhang ◽  
Shu Da Zhou ◽  
Xiu Li Ding ◽  
Shu Ling Huang ◽  
Yu Ting Zhang
Keyword(s):  
Three Dimensional ◽  
Simulation Models ◽  
Arch Dam ◽  
Hydropower Plant ◽  
Underground Powerhouse ◽  
Reservoir Storage ◽  
Underground Caverns ◽  
Operation Period ◽  
Calculation Results ◽  
Key Issues

Considering topographic and geologic conditions, project layout and investments, concret arch dam is adopted in a hydropower plant and underground powerhouses are arranged in mountains on left and right banks. However, the minimum distance between the excavation boundary of abutment of arch dam on elevation 850m and underground powerhouse is only 110m. Abutment load created by reservoir storage, permeability and earthquake may affect general stability of underground caverns in operation period. Thus, using elasto-plastic finite difference method, three dimensional numerical simulation models of underground caverns and slope of abutment of arch dam is establised and proposed key issues are systemly studied. The calculation results show that, under reservoir storage and dam vibration subject to earthquke, abutment load has small effect on plastic zone, displacement and stress around opennings and the caverns would be stable in operation period.

Application of Stereographic Projection in the Search of Key Block of Surrounding Rock Mass for Underground Powerhouse

2010 ◽  
Vol 44-47 ◽  
pp. 1189-1192
Author(s):  
Zhong Chang Wang
Keyword(s):  
Rock Mass ◽  
Stereographic Projection ◽  
Side Wall ◽  
Surrounding Rock ◽  
Main Role ◽  
Measuring Point ◽  
Underground Powerhouse ◽  
Underground Caverns ◽  
Key Block ◽  
The Stability

The rose diagram of joint is generalized by grouping the attitude of disclosed discontinuous faces in detecting cavern and measuring point coordinate. The search of movable and key blocks of surrounding rock mass for underground powerhouse is implemented, the combinations of discontinuous faces and sliding faces, the location and the parameter of stability of movable and key blocks are obtained by used of the method of stereographic projection and vector analysis of the block theory. It is shown that the numbers of movable and key blocks in the location of downriver right side wall and vault are larger than those in other location owing to numerous discontinuous faces, and the faults of F34 and F33 play a main role in the stability of movable and key blocks. The guidance for excavation and reinforce of underground caverns is provided.

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 Mechanical Characteristics of Fully Grouted and Antiseismic Bolts considering Transverse Deformation in Underground Caverns

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Buyun Yang ◽  
Ming Xiao ◽  
Guoqing Liu ◽  
Juntao Chen
Keyword(s):  
Axial Stress ◽  
Time History ◽  
Beam Theory ◽  
Support Effect ◽  
Transverse Force ◽  
Surrounding Rock ◽  
Axial Deformation ◽  
Transverse Deformation ◽  
Rock Interaction ◽  
Underground Caverns

The load transfer control equations under bolt-surrounding rock interaction are established on the basis of classical beam theory and the trilinear shear slip model. The axial stress and transverse shear force distributions of the anchorage body are obtained by solving the equations. The equivalent forces obtained by the transverse force and axial shear stress of the bolts are applied to rock mass elements to simulate the support effect. A new dynamic algorithm for bolts is proposed in considering of the axial and transverse deformation of the anchorage body. The rationality of the algorithm is verified by comparing with laboratory pullout and shear tests of bolts. A dynamic time-history case study of underground caverns is conducted using this algorithm. Results indicate that (1) the algorithm may reflect the stress and deformation characteristics of bolts during an earthquake; (2) for the antiseismic support effect of the surrounding rock at fault, the bolt algorithm in this study is more valid than the algorithm that considered only the axial deformation of bolts; (3) in the support force of the bolt to the surrounding rock, transverse force is the key to limit fault dislocation and reduce the dynamic damage of the rock at fault.

scholarly journals Key Factors Affecting the Deformation and Failure of Surrounding Rock Masses in Large-Scale Underground Powerhouses

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Meng Wang ◽  
Jia-wen Zhou ◽  
An-chi Shi ◽  
Jin-qi Han ◽  
Hai-bo Li
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Surrounding Rock ◽  
Rock Masses ◽  
Affecting Factors ◽  
Key Factors ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Factors Affecting ◽  
Geological Conditions

The stability of the surrounding rock masses of underground powerhouses is always emphasized during the construction period. With the general trends toward large-scale, complex geological conditions and the rapid construction progress of underground powerhouses, deformation and failure issues of the surrounding rock mass can emerge, putting the safety of construction and operation in jeopardy and causing enormous economic loss. To solve these problems, an understanding of the origins and key affecting factors is required. Based on domestic large-scale underground powerhouse cases in the past two decades, key factors affecting the deformation and failure of the surrounding rock mass are summarized in this paper. Among these factors, the two most fundamental factors are the rock mass properties and in situ stress, which impart tremendous impacts on surrounding rock mass stability in a number of cases. Excavation is a prerequisite of surrounding rock mass failure and support that is classified as part of the construction process and plays a pivotal role in preventing and arresting deformation and failure. Additionally, the layout and structure of the powerhouse are consequential. The interrelation and interaction of these factors are discussed at the end of this paper. The results can hopefully advance the understanding of the deformation and failure of surrounding rock masses and provide a reference for design and construction with respect to hydroelectric underground powerhouses.

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