scholarly journals Optimization Analysis of Excavation Procedure Design of Underground Powerhouses under High In Situ Stress in China

2021 ◽  
Vol 11 (21) ◽  
pp. 10252
Author(s):  
Xiao Liu ◽  
Peng Yan ◽  
Ming Chen ◽  
Sheng Luo ◽  
Ang Lu ◽  
...  
Keyword(s):  
Stress Level ◽  
In Situ Stress ◽  
Complex Stress ◽  
Design Parameters ◽  
Rock Classification ◽  
Underground Powerhouse ◽  
High In Situ Stress ◽  
Blasting Excavation ◽  
Stress Levels

To recommend the excavation procedures and design parameters for underground powerhouses, excavation procedures of fifty-one underground powerhouses in China were summarized and analyzed based on in situ stress conditions. Firstly, the complex stress environment in China was introduced and fifty-one underground powerhouses with their engineering scale, size, lithology, rock classification and in situ stress level were listed in detail. Subsequently, to evaluate the influence of in situ stress levels on excavation procedure design, the correlation between excavation procedures and in situ stress level in three main excavation zones were analyzed accordingly. Moreover, to provide the excavation design recommendations, the strength–stress ratio (SSR) was promoted to analyze and recommend the design parameters, and the blasting excavation design based on the stress transient unloading control was also supplemented. The results show that excavation procedures have different priorities under different in situ stress levels, and the design parameters show an obvious relationship with in situ stress levels. Moreover, the excavation procedure parameters are suggested to adjust accordingly under different SSR. The discussion of influencing factors and specification ensures its rationality and accuracy. It is believed that the summary and recommendations can provide a good reference for excavation procedure optimization of underground powerhouse under high in situ stress.

scholarly journals Development of a Model to Predict Vibrations Induced by Blasting Excavation of Deep Rock Masses under High In Situ Stress

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yong Fan ◽  
Xianze Cui ◽  
Zhendong Leng ◽  
Yurong Zhou ◽  
Junwei Zheng ◽  
...  
Keyword(s):  
Prediction Model ◽  
In Situ Stress ◽  
Rock Masses ◽  
Vibration Data ◽  
High In Situ Stress ◽  
Dimension Analysis ◽  
Proposed Model ◽  
Blasting Excavation ◽  
Deep Rock

During the process of blasting excavation of deep rock masses under high in situ stress, energy produced by the explosive and the strain energy released by rock mass excavation constitute the energy source of vibration. However, in traditional Sadov’s empirical formula, the energy produced by explosive explosion is only considered which makes the error higher when it is used to predict the blasting-induced vibration peak under the condition of high in situ stress. In this study, energy transformation and distribution mechanisms caused by excavation of deep rock masses were analyzed at first. Then, a prediction model of vibration peak based on the principle of energy balance was established by dimension analysis. Finally, the proposed model was trained and tested with the vibration data monitored during the blasting excavation of deep buried tunnel in Jinping II hydropower station. The result shows that compared with the traditional prediction model, the proposed model has higher fitting correlation coefficient and lower root-mean-square error, which can be better applied to the prediction of vibration induced by blasting excavation of deep rock masses under high in situ stress.

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 Rock Mass Behavior under Tunnel Widening in Asymmetric and Symmetric Modes Considering Different Shapes and Parametric Conditions

Geosciences ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 518
Author(s):  
Babar Khan ◽  
Syed Muhammad Jamil ◽  
Jung Joo Kim ◽  
Turab H. Jafri ◽  
Jonguk Kim
Keyword(s):  
Rock Mass ◽  
In Situ Stress ◽  
Design Parameters ◽  
Tunnel Widening ◽  
Tunnel Support ◽  
Mass Behavior ◽  
Rock Types ◽  
The Difference ◽  
Support Conditions

To accommodate traffic volume on roads due to ever-increasing population growth, the widening of highways and motorways is in high demand. Nevertheless, the widening of tunnels on these road networks is quite complex due to the presence of numerous rock types, in situ stress, and different widening modes. To overcome these complexities, eight different tunnel shapes were simulated under varying support conditions for asymmetric and symmetric widening. It was found that the tunnels with a round shape, such as horseshoe and semicircular with flatbed, are more effective for asymmetric widening, whereas the provision of a rounded invert in these shapes can reverse the widening option to symmetric. Furthermore, an insignificant effect of the difference in asymmetric and symmetric widening of regular tunnel shapes, such as box, rectangular, and semi-elliptical, was found. A full factorial design statistical analysis confirmed the decrease in tunnel deformation by using various tunnel support systems and showed a significant deformation difference according to monitoring locations at the tunnel periphery. The deformation difference in the case of both tunnel widening modes was also analyzed according to different design parameters. This study provides a comprehensive understanding of rock mass behavior when the widening of any underground opening is carried out.

Research of Mining Method for Difficult-to-Mine Ore Bodies in Deep Mine

2014 ◽  
Vol 962-965 ◽  
pp. 1041-1046
Author(s):  
Qi Fa Ge ◽  
Xue Sen Sun ◽  
Wei Gen Zhu ◽  
Qing Gang Chen
Keyword(s):  
In Situ Stress ◽  
Mining Method ◽  
Deep Mining ◽  
Deep Mine ◽  
Ore Body ◽  
High In Situ Stress ◽  
Ore Bodies ◽  
Large Panel ◽  
Back Filling

There are many problems such as depth, high in-situ stress, high ground temperature and rockburst proneness etc. in deep mining. And it is an acknowledged and urgent mining technical puzzle about mining method of gently inclined and medium-thick ore bodies. For such an ore body in West wing of Dongguashan copper mine, if we use traditional mining method, it is hard to conquer such difficulties as high in-situ stress, large open area in roof, removal of mined ore by gravity etc. The theory of “large panel and lower sublevel height” will be easy to solve such problems. This paper use numerical technology to analyze and compare the technical and economical effectiveness for different selected mining method and its structure. The sublevel (at a height of 12 m) open stoping with back-filling by extraction in two steps is quite suitable for ensuring safety, increasing efficiency, productivity and reclaiming resource. The selected method is feasible and well worth spread.

Yielding and rupture in a lacustrine clay

1980 ◽  
Vol 17 (4) ◽  
pp. 559-573 ◽  
Author(s):  
A. Baracos ◽  
J. Graham ◽  
L. Domaschuk
Keyword(s):  
Shear Failure ◽  
Friction Angle ◽  
In Situ Stress ◽  
Grain Structure ◽  
Testing Procedures ◽  
Straight Line ◽  
Stress Levels ◽  
Lacustrine Clay ◽  
Field Behaviour

Recent tests have examined the properties of block samples and tube samples from depths to 12 m in Winnipeg clay. Careful trimming and a wide variety of testing procedures have permitted new insights into the behaviour of the clay that is markedly anisotropic and non-homogeneous. The effective strength envelope for "blue clay" from 6 to 12 m depth can be simplified into three straight-line sections. At low stresses, a section of the envelope has been identified having a low cohesion intercept and a high "friction" angle. This is thought to be caused by close Assuring in the clay, and controls the field behaviour in many small embankment, riverbank, and excavation problems. At in situ stress levels, the clay dilates markedly as failure is approached. Porewater pressures depend strongly on stress levels during laboratory reconsolidation. Residual strengths are low, and are influenced by the methods used during testing. Yielding has been clearly identified for shear failure of the grain structure, but is more poorly defined for increasing normal octahedral stresses. The work has emphasized the importance of selecting appropriate testing procedures and stresses for field applications.

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