Dynamic Unloading Instability Mechanism of Underground Cavern Based on Seepage-Damage Coupling

2020 ◽  
Vol 24 (5) ◽  
pp. 1620-1631
Author(s):  
Liping Li ◽  
Wenfeng Tu ◽  
Zongqing Zhou ◽  
Shaoshuai Shi ◽  
Mingguang Zhang ◽  
...  
Keyword(s):  
Instability Mechanism ◽  
Underground Cavern ◽  
Dynamic Unloading

Catastrophic Analysis of Seismic Response of Gravity Dam Sliding along Base Surface

2011 ◽  
Vol 311-313 ◽  
pp. 2164-2168
Author(s):  
Dun Ben Sun ◽  
Qing Wen Ren
Keyword(s):  
Weibull Model ◽  
Gravity Dam ◽  
Stable Region ◽  
Instability Mechanism ◽  
Gravity Dams ◽  
Base Surface ◽  
Instability Problem ◽  
Nonlinear Constitutive Model ◽  
Hysteresis Phenomena ◽  
Sliding Instability

For the instability problem of gravity dam sliding along base surface, cubic nonlinear constitutive model of soft material in base surface is adopted, which is usually expressed by Weibull model. Dynamic Equations of dam sliding along base surface is established. By means of catastrophe theory, the jumping and hysteresis phenomena of the vibration amplitude of the dam is analyzed, the parameter range of stable region in which amplitude doesn’t happen catastrophe is given and the factors which cause amplitude instability are discussed. The results obtained in the paper are of significant value for understanding the sliding instability mechanism of gravity dam under earthquake, as well as guiding the design of gravity dams.

Tidal excitation of hydromagnetic waves and their damping in the Earth

1994 ◽  
Vol 274 ◽  
pp. 219-241 ◽  
Author(s):  
R. R. Kerswell
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Outer Core ◽  
Decay Rates ◽  
Wave Disturbance ◽  
Instability Mechanism ◽  
The Earth ◽  
Elliptical Instability ◽  
Hydromagnetic Waves

We examine the possibility that the Earth's outer core, as a tidally distorted fluid-filled rotating spheroid, may be the seat of an elliptical instability. The instability mechanism is described within the framework of a simple Earth-like model. The preferred forms of wave disturbance are explored and a likely growth rate supremum deduced. Estimates are made of the Ohmic and viscous decay rates of such hydromagnetic waves in the outer core. Rather than a conclusive disparity of scales, we find that typical elliptical growth rates, Ohmic decay rates and viscous decay rates all have the same order for plausible core fields and core-to-mantle conductivities. This study is all the more timely considering the recent realization that the Earth's precession may also drive similar instabilities at comparable strengths in the outer core.

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