Dynamic response and control of middle rock sidewall under impact of blast loading

2019 ◽  
Vol 25 (9) ◽  
pp. 1572-1584
Author(s):  
Yingguo Hu ◽  
Wenbo Lu ◽  
Le Zhang ◽  
Peng Yan
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Stress Wave ◽  
Theoretical Calculations ◽  
Damage Threshold ◽  
The Three Gorges ◽  
Blasting Excavation ◽  
The Three Gorges Project ◽  
And Control ◽  
Spatial Distribution Characteristic

This study focuses on the dynamic response and control of middle rock sidewall (MRS) during blasting. First, the spatial distribution characteristic of blasting vibration in MRS was investigated thoroughly based on the blasting of temporary ship lock and ship lift of the Three Gorges project. Results demonstrated that the distribution of peak particle velocity (PPV) in MRS is parabolic, and the vibration amplification could be found obviously at the free surface. Site experiments were designed to determine the damage threshold of PPV used in the vibration control of blasting excavation of MRS. Results indicated that the PPV threshold of MRS is stricter than that of the conventional condition due to its unique geometric shape. Then numerical simulation was implemented to reproduce the dynamic response in MRS under blasting by using the LS-DYNA commercial software. Results revealed that the PPV distribution obtained by numerical simulation match well with that of site experiments. The reflection and superposition processes of blasting stress wave were investigated and verified against the comparison between different kinds of stress waves. Finally, the most optimal width of MRS was determined to make the peaks and troughs of different stress wave occur at the same position according to the interference theory of stress wave. The results of numerical simulation and theoretical calculations were compared to verify the rationality of the optimal width determination.

Alkali Activity of Granite Aggregates and Control in the Concrete of the Three Gorges Project

2013 ◽  
Vol 539 ◽  
pp. 249-254
Author(s):  
Zai Qin Wang ◽  
Chong Xi Liu ◽  
Zi Yun Wen ◽  
Zhen Li ◽  
Liang Xiao
Keyword(s):  
Standardized Test ◽  
Expansion Ratio ◽  
Test Methods ◽  
Observation Time ◽  
Three Gorges Project ◽  
Three Gorges ◽  
Concrete Aggregates ◽  
The Three Gorges ◽  
The Three Gorges Project ◽  
And Control

On the basis of the existing standardized test methods of concrete aggregates alkali activity, the alkali activity of the granite aggregates is studied by extending the observation time. The results showed that the alkali reaction expansion ratio of the fresh granite broke through the 0.1% criterion limit after a decade of time. The reactant microstructure characteristic is similar to the structure of the alkali-silica reaction, the thickness of reaction layer is about 2~4 µm. Controlling the total alkali content of the dam concrete and replacing cement by mixing a certain proportion of fly ash can effectively prevent the occurrence of the AAR in the Three Gorges Project.

scholarly journals Dynamic Response of Rock-like Materials Based on SHPB Pulse Waveform Characteristics

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 210
Author(s):  
Bi Sun ◽  
Rui Chen ◽  
Yang Ping ◽  
Zhende Zhu ◽  
Nan Wu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Strain Rate ◽  
Stress Wave ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Pulse Waveform ◽  
Inertia Effect ◽  
Critical Interval ◽  
Rate Gradient

Rock-like brittle materials under dynamic load will show more complex dynamic mechanical properties than those under static load. The relationship between pulse waveform characteristics and strain rate effect and inertia effect is rarely discussed in the split-Hopkinson pressure bar (SHPB) numerical simulation research. In response to this problem, this paper discusses the effects of different pulse types and pulse waveforms on the incident waveform and dynamic response characteristics of specimens based on particle flow code (PFC). The research identifies a critical interval of rock dynamic strength, where the dynamic strength of the specimen is independent of the strain rate but increases with the amplitude of the incident stress wave. When the critical interval is exceeded, the dynamic strength is determined by the strain rate and strain rate gradient. The strain rate of the specimen is only related to the slope of the incident stress wave and is independent of its amplitude. It is also determined that the inertia effect cannot be eliminated in the SHPB. The slope of the velocity pulse waveform determines the strain rate of the specimen, the slope of the force pulse waveform determines the strain rate gradient of the specimen, and the upper bottom time determines the strain rate of the specimen. It provides a reference for SHPB numerical simulation. A dynamic strength prediction model of rock-like materials is then proposed, which considers the effects of strain rate and strain rate gradient.

In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects

2004 ◽  
Vol 261-263 ◽  
pp. 1097-1102 ◽  
Author(s):  
Jian Liu ◽  
Xia Ting Feng ◽  
Xiu Li Ding ◽  
Huo Ming Zhou
Keyword(s):  
Rock Mass ◽  
Creep Behavior ◽  
Large Scale ◽  
Time Dependent ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.

scholarly journals Strata behavior and control strategy of backfilling collaborate with caving fully-mechanized mining

2020 ◽  
Vol 12 (1) ◽  
pp. 703-717
Author(s):  
Yin Wei ◽  
Wang Jiaqi ◽  
Bai Xiaomin ◽  
Sun Wenjie ◽  
Zhou Zheyuan
Keyword(s):  
Numerical Simulation ◽  
Control Strategy ◽  
Three Dimensional ◽  
Simulation Method ◽  
Mine Pressure ◽  
Hydraulic Support ◽  
Transition Area ◽  
Pressure Concentration ◽  
Strata Behavior ◽  
And Control

AbstractThis article analyzes the technical difficulties in full-section backfill mining and briefly introduces the technical principle and advantages of backfilling combined with caving fully mechanized mining (BCCFM). To reveal the strata behavior law of the BCCFM workface, this work establishes a three-dimensional numerical model and designs a simulation method by dynamically updating the modulus parameter of the filling body. By the analysis of numerical simulation, the following conclusions about strata behavior of the BCCFM workface were drawn. (1) The strata behavior of the BCCFM workface shows significant nonsymmetrical characteristics, and the pressure in the caving section is higher than that in the backfilling section. φ has the greatest influence on the backfilling section and the least influence on the caving section. C has a significant influence on the range of abutment pressure in the backfilling section. (2) There exits the transition area with strong mine pressure of the BCCFM workface. φ and C have significant effect on the degree of pressure concentration but little effect on the influence range of strong mine pressure in the transition area. (3) Under different conditions, the influence range of strong mine pressure is all less than 6 m. This article puts forward a control strategy of mine pressure in the transition area, which is appropriately improving the strength of the transition hydraulic support within the influence range (6 m) in the transition area according to the pressure concentration coefficient. The field measurement value of Ji15-31010 workface was consistent with numerical simulation, which verifies the reliability of control strategy of the BCCFM workface.

Numerical Simulation of Blasting-Induced Damage in Grouting Curtain of Sandstone Aquifer for Vertical Shaft

2015 ◽  
Vol 723 ◽  
pp. 271-278
Author(s):  
Yu Liang Zhou ◽  
Dong Feng Yuan ◽  
Jun Zheng ◽  
Hua Wang
Keyword(s):  
Numerical Simulation ◽  
Prevention And Control ◽  
Damage Zone ◽  
Surrounding Rock ◽  
Damage Effect ◽  
Vertical Shaft ◽  
Control Methods ◽  
Sandstone Aquifer ◽  
And Control ◽  
Dynamic Damage

To provide a theoretical basis for water prevention and control methods and reasonable supporting techniques for vertical shaft, and to ensure the shaft construction to pass the sandstone aquifer safely and rapidly, numerical simulation using dynamic damage constitutive model, which was a user-defined constitutive modules in FLAC3D, a lagrangian analysis code in three dimensions, has been applied to investigate the dynamic damage effect in the surrounding rock of the grouting curtain near the driving working face for vertical shaft excavated by blasting. The results indicate that the distribution of the damage zone in the surrounding rock of the shaft, which decreases the effective thickness of the grouting curtain, was like a ellip-se, and that the depth of the damage zone in the surrounding rock of the shaft grouting curtain is fewer than that of the driving face floor. It can be concluded that the centre part of the driving face floor, especially the cutting hole zones, and the shaft wall in the greater horizontal stress side are the " key parts " for shaft water prevention and control methods.

scholarly journals How the Three Gorges Project (TGP) affects local precipitation

2021 ◽  
Author(s):  
Qin Li ◽  
Yulong Zhong ◽  
Xiuguo Liu ◽  
Mengmeng Wang ◽  
Manxing Shi
Keyword(s):  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

scholarly journals Seismic hazard assessment of the Three Gorges Project

2013 ◽  
Vol 4 (2) ◽  
pp. 53-60 ◽  
Author(s):  
Yao Yunsheng ◽  
Wang Qiuliang ◽  
Li Jinggang ◽  
Shen Xueling ◽  
Kong Yuyang
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project
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