Large-scale geomechanical model testing of an underground cavern group in a true three-dimensional (3-D) stress state

2010 ◽  
Vol 47 (9) ◽  
pp. 935-946 ◽  
Author(s):  
W. S. Zhu ◽  
Q. B. Zhang ◽  
H. H. Zhu ◽  
Y. Li ◽  
J.-H. Yin ◽  
...  
Keyword(s):  
Stress State ◽  
Large Scale ◽  
Three Dimensional ◽  
Great Depth ◽  
Model Tests ◽  
Geomechanical Model ◽  
Testing Procedures ◽  
Test Initiation ◽  
The Stability ◽  
Made In

The stability of a large cavern group at great depth is discussed on the basis of large-scale three-dimensional (3-D) geomechanical model tests and numerical simulations. The model tests are described in detail. Improvements in the tests were made in terms of experimental techniques and advanced measurement methods. The model tests utilized active loading on six sides of a rock mass in a true 3-D stress state. During the model construction, precast blocks were fabricated and monitoring holes were defined prior to test initiation. Newly developed combination ball-sliding walls were installed on each of the major loading surfaces to reduce the friction induced by model deformation. A unique grouting and installation technique employing prestressed cables was adopted in the tests. A digital photogrammetric technique, displacement sensing bars using fiber Bragg grating (FBG) technology, and mini multipoint extensometers were developed for measuring deformation. Overloading tests were then conducted for different overburden depths, and 3-D numerical analyses were performed to simulate the testing procedures. Conclusions regarding the stability of the cavern group were developed based on a comparison between the experimental and numerical results.

Design and Manufacture of a New Large-Scale Three-Dimensional Geomechanics Model Test System

2010 ◽  
Vol 97-101 ◽  
pp. 2770-2773
Author(s):  
Wei Shen Zhu ◽  
Yong Li ◽  
Min Yong ◽  
Q.B. Zhang ◽  
Shu Cai Li
Keyword(s):  
Model Test ◽  
Large Scale ◽  
Three Dimensional ◽  
Great Depth ◽  
Test System ◽  
Great Stability ◽  
Underground Caverns ◽  
Structural Frame ◽  
The Stability ◽  
Design And Manufacture

Geomechanics modeling has played important role in geotechnical engineering. In order to investigate on the stability of underground caverns at great depth, a large-scale geomechanics model test system was designed and manufactured. The system mainly consisted of a steel structural frame and a hydraulic loading control system, which can apply active loading on six sides with a true three-dimensional stress state. Newly developed combinational ball sliding walls were installed on each of the major loading surfaces, which were significantly reduced the friction due to model deformation. The system has apparent technical advantages such as high stiffness, great stability, and flexibility of assembly, and easy adjustment of its dimensions.

Potential Flow Field Generated by Downstream Moving Bars and Propagated on a Turbine Blade at Low Reynolds Number

2011 ◽  
Author(s):  
Ve´ronique Penin ◽  
Pascale Kulisa ◽  
Franc¸ois Bario
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Numerical Study ◽  
Three Dimensional ◽  
Potential Effect ◽  
Navier Stokes ◽  
Turbine Cascade ◽  
Wake Interaction ◽  
Rotor Stator Interaction ◽  
The Stability

During the last few decades, the size and weight of turbo-machinery have been continuously reduced. However, by decreasing the distance between rows, rotor-stator interaction is strengthened. Two interactions now have the same magnitude: wake interaction and potential effect. Studying this effect is essential to understand rotor-stator interactions. Indeed, this phenomenon influences the whole flow, including the boundary layer of the upstream and downstream blades, ergo the stability of the flow and the efficiency of the machine. A large scale turbine cascade followed by a specially designed rotating cylinder system is used. Synchronised velocity LDA measurements on the vane profile show the flow and boundary layer behavior due to the moving bars. To help the general understanding and to corroborate our experimental results, numerical investigations are carried out with an unsteady three dimensional Navier-Stokes code. Moreover, the numerical study informs about the potential disturbance to the whole flow of the cascade.

Unsteady Three-Dimensional Turbine Aerodynamics

1983 ◽  
Vol 105 (2) ◽  
pp. 322-331 ◽  
Author(s):  
H. D. Joslyn ◽  
R. P. Dring ◽  
O. P. Sharma
Keyword(s):  
Total Pressure ◽  
Velocity Vector ◽  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
High Response ◽  
Phase Lock ◽  
Reduced Data ◽  
Made In ◽  
Periodic Changes

High response aerodynamic measurements were made in a large-scale, axial, flow turbine model to study the unsteadiness and three dimensionality of the flow. High response velocity vector and total pressure data were acquired. A comparison was made of the results of phase lock averaging both raw and reduced data (voltages and velocities). The velocity vector measurements showed that there were strong radial flows present as well as significant periodic changes in the flow field due to relative rotor and vane positions. Random, periodic, and total unsteadiness levels were computed from the instantaneous and phase-lock-averaged velocity data. Time-averaged data were compared with an inviscid two-dimensional calculation. A comparison was also made of time-averaged total pressure measurements obtained from high-response and low-response (steady-state) probes.

Application of Damage Rheology Model in Study on an Underground Cavern Group

2011 ◽  
Vol 90-93 ◽  
pp. 760-763
Author(s):  
Yin Ping Qi ◽  
Lv Xiang ◽  
Wei Shen Zhu
Keyword(s):  
Large Scale ◽  
Southwest China ◽  
Back Analysis ◽  
Great Depth ◽  
Underground Cavern ◽  
In Situ Stresses ◽  
The Stability ◽  
Damage Rheology ◽  
Hydropower Stations

A great number of large-scale hydropower stations are to be constructed in southwest China. Many of them feature great depth or high in situ stresses. In this paper, a coupled damage and rheology method is adopted for stability analysis of an underground cavern group with time effect to consider the rock deformation. Meanwhile, a new method considering the crackopening displacement is used for back analysis. The stability of the surrounding rock masses is then evaluated.

scholarly journals A Large Goaf Group Treatment by means of Mine Backfill Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Hanwen Jia ◽  
Baoxu Yan ◽  
Erol Yilmaz
Keyword(s):  
Group Treatment ◽  
Laser Scanning ◽  
Large Scale ◽  
Mechanical Characteristics ◽  
Three Dimensional ◽  
Stability Diagram ◽  
Surrounding Rock ◽  
Mine Backfill ◽  
Treatment Scheme ◽  
The Stability

There are few studies on the management methods of large-scale goaf groups per the specific surrounding rock mass conditions of each goaf. This paper evaluates comprehensively the stability of the multistage large-scale goaf group in a Pb-Zn mine in Inner Mongolia, China, via the modified Mathews stability diagram technique. The volume of each goaf to be backfilled was quantitatively analyzed in the combination of theoretical analysis and three-dimensional laser scanning technology. The corresponding mechanical characteristics of the filling were determined by laboratory testing while formulating the treatment scheme of the large goaf group using the backfill method. The applicability of the treatment scheme using the backfill was verified by the combination of the numerical results of the distribution of the surrounding rock failure zone and the monitored data of the surface subsidence. The research results and treatment scheme using the backfill can provide a reference for similar conditions of mines worldwide.

Unsteady Three-Dimensional Turbine Aerodynamics

1982 ◽  
Author(s):  
H. D. Joslyn ◽  
R. P. Dring ◽  
O. P. Sharma
Keyword(s):  
Total Pressure ◽  
Velocity Vector ◽  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
High Response ◽  
Phase Lock ◽  
Reduced Data ◽  
Made In ◽  
Periodic Changes

High response aerodynamic measurements were made in a large scale, axial, flow turbine model to study the unsteadiness and three dimensionality of the flow. High response velocity vector and total pressure data were acquired. A comparison was made of the results of phase lock, averaging both raw and reduced data (voltages and velocities). The velocity vector measurements showed that there were strong radial flows present as well as significant periodic changes in the flow field due to relative rotor and vane positions. Random, periodic, and total unsteadiness levels were computed from the instantaneous and phase lock averaged velocity data. Time averaged data were compared with an inviscid two-dimensional calculation. A comparison was also made of time averaged total pressure measurements obtained from high response and low response (steady-state) probes.

scholarly journals The Stability Principle and global weak solutions of the free surface semi-geostrophic equations in geostrophic coordinates

2019 ◽  
Vol 475 (2229) ◽  
pp. 20180787
Author(s):  
M. J. P. Cullen ◽  
T. Kuna ◽  
B. Pelloni ◽  
M. Wilkinson
Keyword(s):  
Weak Solutions ◽  
Large Scale ◽  
Optimal Transport ◽  
Three Dimensional ◽  
Mathematical Framework ◽  
Atmospheric Flows ◽  
Stability Principle ◽  
The Stability ◽  
Dimensional Domain ◽  
Upper Boundary

The semi-geostrophic equations are used widely in the modelling of large-scale atmospheric flows. In this note, we prove the global existence of weak solutions of the incompressible semi-geostrophic equations, in geostrophic coordinates, in a three-dimensional domain with a free upper boundary. The proof, based on an energy minimization argument originally inspired by the Stability Principle as studied by Cullen, Purser and others, uses optimal transport techniques as well as the analysis of Hamiltonian ODEs in spaces of probability measures as studied by Ambrosio and Gangbo. We also give a general formulation of the Stability Principle in a rigorous mathematical framework.

scholarly journals BREAKING WAVE KINEMATICS, LOCAL PRESSURES, AND FORCES ON A TRIPOD STRUCTURE

2012 ◽  
Vol 1 (33) ◽  
pp. 71 ◽  
Author(s):  
Arndt Hildebrandt ◽  
Torsten Schlurmann
Keyword(s):  
Wave Front ◽  
Wave Breaking ◽  
Large Scale ◽  
Three Dimensional ◽  
Model Tests ◽  
Scale Model ◽  
Breaking Wave ◽  
Wave Loads ◽  
Large Wave ◽  
The Impact

This paper presents breaking wave loads on a tripod structure from physical model tests and numerical simulations. The large scale model tests (1:12) are described as well as the validation of the three dimensional numerical model by comparison of CFD wave gauge data and pressures with measurements in the large wave flume inside and outside the impact area. Subsequently, the impact areas due to a broken wave, a curled wave front as well as for wave breaking directly at the structure with a partly vertical wave front are compared to each other. Line forces in terms of slamming coefficients with variation in time and space are derived from CFD results and the velocity distribution is presented at the onset of wave breaking. Finally, the results are briefly discussed in comparison to other slamming studies.

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