Relation of Textural Stress and Rock Failure of Diversion Tunnel

2011 ◽  
Vol 243-249 ◽  
pp. 3685-3688
Author(s):  
Rui Gao
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Field ◽  
Multivariate Regression ◽  
Large Scale ◽  
Regression Method ◽  
Rock Failure ◽  
Hydropower Station ◽  
Diversion Tunnel ◽  
The Stability

The textural stress has great effect on the stability of rock. According to the measured geo-stress data, through FEM and combined with the linear multivariate regression method, the geo-stress field was conducted. Using these methods, a diversion tunnel of a large-scale hydropower station was analyzed to study the stress distribution. It was shown that the stress concentration was located at the bottom of the wall and the arch top, the stress in the wall was little and the failure happened at the bottom of the wall and the arch top, then the bottom board and some areas far from the tunnel. Under the condition without considering textural stress, the stress concentration area located in the wall and the failure happened at the bottom of the wall, then in the middle of the wall and at the arch top.

scholarly journals In-situ rock tests for fault gouge zone：A case in Fengman hydropower station, China

2021 ◽  
Vol 293 ◽  
pp. 03008
Author(s):  
Xinchuan Xu ◽  
Zhaoyue Yu ◽  
Fangfang Xue ◽  
Xiaogang Long ◽  
Xinyu Mao ◽  
...  
Keyword(s):  
Large Scale ◽  
Scientific Basis ◽  
Test Point ◽  
Actual Condition ◽  
Hydropower Station ◽  
Bearing Plate ◽  
Dam Site ◽  
Fault Gouges ◽  
The Stability

The existence of faults in the dam site area threatens the stability and safety of large-scale hydropower projects in China. The fault argillaceous zone is the worst kind of fault fracture zone, and the determination of its deformation and strength parameters is the key point of rock engineering investigation. In this study, the in-situ bearing plate test and direct shear test were carried out on the gouge zone of F67 fault in the dam site of Fengman Hydropower Station. The test results show that the deformation and shear law of each test point is good, which is basically consistent with the actual condition of the measured rock mass. However, due to the limited number of measurements, the results are limited in terms of macroscopic representation. The experimental results provide scientific basis for subsequent engineering design and further enhance the understanding of mechanical properties of fault gouges.

Study on Design of Tunnel Section for Danba Diversion Tunnel

2014 ◽  
Vol 501-504 ◽  
pp. 1732-1735
Author(s):  
Jie Liu ◽  
Liang Tang ◽  
Ya Zuo ◽  
Jin Long Guo
Keyword(s):  
Stability Analysis ◽  
Plastic Zone ◽  
Cross Sections ◽  
Surrounding Rock ◽  
Hydropower Station ◽  
Diversion Tunnel ◽  
Rock Stability ◽  
Tunnel Section ◽  
Tunnel Design ◽  
The Stability

Analyzing and Evaluating the stability of the surrounding rock is an indispensable and important part in the tunnel design. In this paper, the surrounding rock stability of Danba hydropower station diversion tunnel is dealt with, FLAC3Dsoftware is used for stability analysis. Selecting three different cross sections for calculation models, comparing with the displacement and principal stress and the plastic zone which calculated by FLAC3D, we can evaluate their stability and get the best diversion tunnel design.

scholarly journals Molecular Understanding of Electrochemical–Mechanical Responses in Carbon-Coated Silicon Nanotubes during Lithiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 564
Author(s):  
Chen Feng ◽  
Shiyuan Liu ◽  
Junjie Li ◽  
Maoyuan Li ◽  
Siyi Cheng ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Compressive Stress ◽  
Structural Stability ◽  
Large Scale ◽  
Electrode Materials ◽  
Morphological Evolution ◽  
Lithium Ion ◽  
Commercial Application ◽  
Carbon Coated

Carbon-coated silicon nanotube (SiNT@CNT) anodes show tremendous potential in high-performance lithium ion batteries (LIBs). Unfortunately, to realize the commercial application, it is still required to further optimize the structural design for better durability and safety. Here, the electrochemical and mechanical evolution in lithiated SiNT@CNT nanohybrids are investigated using large-scale atomistic simulations. More importantly, the lithiation responses of SiNW@CNT nanohybrids are also investigated in the same simulation conditions as references. The simulations quantitatively reveal that the inner hole of the SiNT alleviates the compressive stress concentration between a-LixSi and C phases, resulting in the SiNT@CNT having a higher Li capacity and faster lithiation rate than SiNW@CNT. The contact mode significantly regulates the stress distribution at the inner hole surface, further affecting the morphological evolution and structural stability. The inner hole of bare SiNT shows good structural stability due to no stress concentration, while that of concentric SiNT@CNT undergoes dramatic shrinkage due to compressive stress concentration, and that of eccentric SiNT@CNT is deformed due to the mismatch of stress distribution. These findings not only enrich the atomic understanding of the electrochemical–mechanical coupled mechanism in lithiated SiNT@CNT nanohybrids but also provide feasible solutions to optimize the charging strategy and tune the nanostructure of SiNT-based electrode materials.

scholarly journals Stability Analysis of Steel Lining at Pressure Diversion Tunnel Collapse Zone during Operating Period

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ming Xiao ◽  
Chen Zhao
Keyword(s):  
Large Scale ◽  
Water Pressure ◽  
Concrete Lining ◽  
Seepage Field ◽  
Diversion Tunnel ◽  
Steel Lining ◽  
Internal Water ◽  
External Water Pressure ◽  
External Water ◽  
The Stability

At the collapse zone, the effects of the thickness of the consolidation grouting layer and the water pressure on the steel lining are vital to the stability of steel-lined pressure diversion tunnels. In this paper, a joint element and the load-sharing ratio of the consolidation layer are introduced to investigate the joint load-bearing characteristics of the steel lining and the consolidation layer and to determine a suitable consolidation layer thickness; a coupling method for simulating the hydromechanical interaction of the reinforced concrete lining is adopted to investigate the effect of internal water exosmosis on the seepage field at the collapse zone and to determine the external water pressure on the steel lining. In the case of a steel-lined pressure diversion tunnel, a numerical simulation is implemented to analyse the effect of the thickness of the consolidation layer and the distribution of the seepage field under the influence of internal water exosmosis. The results show that a 10 m thick consolidation layer and the adopted antiseepage measures ensure the stability of the steel lining at the collapse zone under internal and external water pressure. These research results provide a reference for the design of treatment measures for large-scale collapses in steel-lined pressure tunnels.

Multi-Parameter Based Stress Distribution in Vicinity of Sharp Material Inclusion Tip

2016 ◽  
Vol 258 ◽  
pp. 169-173
Author(s):  
Ondřej Krepl ◽  
Jan Klusák
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Fracture Mechanics ◽  
Stress Field ◽  
Crack Initiation ◽  
Electronic Components ◽  
Precise Description ◽  
Singular Stress ◽  
Stress Concentrators

General Singular Stress Concentrators (GSSCs) which exhibit singular stress concentration are often responsible for crack initiation and thus failure of the component. The GSSC of the type of bonded bi-material junction occurs in a variety of technical applications including but not limited to sharp material inclusions, silicate based composites and electronic components. The GSSC cannot be assessed by means of standard fracture mechanics. Approaches of generalized fracture mechanics require precise description of stress distribution near the stress concentration points. In order to determine the stress field accurately, the paper incorporates the multi-parameter based description.

scholarly journals Preliminary Research on Response of GCr15 Bearing Steel under Cyclic Compression

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3443
Author(s):  
Xiaomeng Zheng ◽  
Yongzhen Zhang ◽  
Sanming Du
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
Large Scale ◽  
Matrix Material ◽  
Rolling Direction ◽  
Bearing Steel ◽  
Additional Stress ◽  
Cyclic Compression ◽  
The Asymmetry ◽  
The Relationship

During the bearing service, a series of microstructural evolutions will arise inside the material, such as the appearance of feature microstructures. The essential reason for the microstructural evolution is the cumulative effect of cyclic stress. The Hertz Contact formula is usually adopted to calculate the internal stress, and there is a correlation between the shape and distribution of the feature microstructure and the stress distribution. But it is insufficient to explain the relationship between the morphology of feature microstructures and the rolling direction, such as specific angles in butterfly and white etching bands. The rolling phenomenon will cause the asymmetry of stress distribution in the material, which is the source of the rolling friction coefficient. Moreover, slipping or microslip will produce additional stress components, which also cause the asymmetry of the stress field. However, there is no experimental or theoretical explanation for the relationship between the asymmetry of the stress field and the feature microstructure. According to the current theory, the appearance of feature microstructures is caused by stress with or without rolling. Therefore, it is of great significance to study the formation mechanism: whether feature microstructures will appear in the uniaxial cyclic compression stress field without rolling. In this paper, uniaxial cyclic compressive stress was loaded into a plate-ball system and a cylinder system. The characteristics of microstructural change of bearing steel (GCr15) were studied. It was found that the hardness of the material increased after the cyclic compressive load, and the inclusions interacted with the matrix material. In the local microregion a white etching area was found, although the scale is very small. No large-scale feature microstructures appeared. Other phenomena in the experiment are also described and analyzed. For example, the production of oil film in the contact area and the changing law of alternating load.

The Stress Distribution and Calculation of the Different Zone of Wellbore Surrounding Rock Based on the Damaged Theory

2012 ◽  
Vol 170-173 ◽  
pp. 1052-1055
Author(s):  
Wan Chun Zhao ◽  
Chen Yan Sun ◽  
Ting Ting Wang ◽  
Yu Liu ◽  
Cai Ping Yang
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Oil Well ◽  
Damage Area ◽  
Stress Direction ◽  
The Stability ◽  
Adjacent Rock

In order to describe the stability of borehole face and the theory of hydraulic fracture fissure stretch in real, the stress field of adjacent rock in the hole should be constituted exactly .The article is based on the damnification dynamics theory, meanwhile, considered the rock is fracture-pore dual medium and the damnification characteristic of the rock in hole .Adjacent formation is sectioned three areas: damage-area, damnification-area, elasticity-area. And we have calculated the ambient stress distribution of one oil-well .The results show that the destructive radius of the minimum in-situ stress direction is 1.247m, the damage radius is 8.082m, the destructive radius of the maximum in-situ stress direction is 0.998m, and the damage radius is 6.5865m.

scholarly journals Stress Distribution and Mechanical Behaviour of Rock Mass Containing Two Openings Underground: Analytical and Numerical Studies

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lihai Tan ◽  
Gaofeng Wang ◽  
Ting Ren ◽  
Linming Dou ◽  
Xiaohan Yang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Large Scale ◽  
Numerical Solutions ◽  
Numerical Models ◽  
Interaction Mechanism ◽  
Confining Stress ◽  
Failure Patterns ◽  
Coalescence Pattern

In this study, stress solution for rock mass containing two rectangular openings was calculated based on the Schwarz alternating method to investigate the stress distribution in rock mass around openings with different layouts. In addition, large-scale numerical models were further established for the two-opening system by means of the PFC-FLAC coupling method, in which the stress evolution, failure patterns, and acoustic emission (AE) events were presented. With the combination of analytical and numerical solutions, the interaction mechanism between two openings under different layouts was discussed from the perspective of stress and failure. The result shows that the confining stress within a certain range contributes to relieving tensile stress concentration around openings. The stress condition within the connecting area and coalescence pattern between two adjacent openings is dominated by their layout. Compared with small-size rock specimens in laboratory tests, the failure patterns around openings show a better agreement with the stress concentration characteristics determined by analytical stress solutions.

scholarly journals Stress analysis of infinite laminated composite plate with elliptical cutout under different in plane loadings in hygrothermal environment

2021 ◽  
Vol 8 (1) ◽  
pp. 1-12
Author(s):  
Ashok Magar ◽  
Achchhe Lal
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Composite Plate ◽  
Volume Fraction ◽  
Elliptical Hole ◽  
Laminated Composite ◽  
Laminated Composite Plate ◽  
Concentration Changes ◽  
Hygrothermal Environment ◽  
Plate Analysis

Abstract This paper presents the solution of stress distribution around elliptical cutout in an infinite laminated composite plate. Analysis is done for in plane loading under hygrothermal environment. The formulation to obtain stresses around elliptical hole is based on Muskhelishvili’s complex variable method. The effect of fibre angle, type of in plane loading, volume fraction of fibre, change in temperature, fibre materials, stacking sequence and environmental conditions on stress distribution around elliptical hole is presented. The study revealed, these factors have significant effect on stress concentration in hygrothermal environment and stress concentration changes are significant with change in temperature.

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