scholarly journals LONG-TERM FLUCTUATION IN DYNAMIC CHARACTERISTICS AND PROPAGATING BEHAVIORS OF SEISMIC MOTION IN A ROCKFILL DAM-FOUNDATION SYSTEM

2019 ◽  
Vol 7 (1) ◽  
pp. 72-84
Author(s):  
Norihisa MATSUMOTO ◽  
Nario YASUDA ◽  
Zengyan CAO
Keyword(s):  
Dynamic Characteristics ◽  
Dam Foundation ◽  
Seismic Motion ◽  
Rockfill Dam ◽  
Term Fluctuation

scholarly journals A Comprehensive Evaluation of Rejuvenator on Mechanical Properties, Durability, and Dynamic Characteristics of Artificially Aged Asphalt Mixture

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1554 ◽  
Author(s):  
Pan Pan ◽  
Yi Kuang ◽  
Xiaodi Hu ◽  
Xiao Zhang
Keyword(s):  
Mechanical Properties ◽  
Dynamic Characteristics ◽  
Comprehensive Evaluation ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Physical Property ◽  
Fatigue Property ◽  
Physical Test ◽  
Aged Asphalt

In this study, the aged asphalt binder and mixture were laboratory prepared through short-term ageing testing and long-term ageing testing. Firstly, the effect of rejuvenator on physical properties of aged asphalt binders was investigated. In addition, a series of laboratory tests were performed to evaluate the influence of ageing and rejuvenator content on the mechanical properties, durability and dynamic characteristics of asphalt mixtures. Physical test results of asphalt binder testified that rejuvenator used can efficiently recover the aged asphalt binder. However, the effect of ageing and rejuvenator content exhibits different trends depending on the physical property tests conducted. Moreover, artificially aged asphalt mixture with rejuvenator has better ability to resist moisture damage and ravelling. In addition, the ITSR value is more suitable to evaluate the moisture susceptibility for asphalt recycling. Although rejuvenator improves the thermal cracking resistance and fatigue property of aged asphalt mixture, rejuvenated mixture shows greater modulus and inferior ability to resist reflective cracking than the unaged mixture. Moreover, rejuvenated mixture shows less dependence on frequency at high temperature regions and stronger dependence at low temperature regions compared to unaged and long-term aged mixtures.

scholarly journals Long-Term Behavior of Coarse-Grained Rockfill Material and Their Constitutive Modeling

2021 ◽  
Author(s):  
Erich Bauer
Keyword(s):  
Mechanical Response ◽  
Coarse Grained ◽  
Geological Condition ◽  
Dam Foundation ◽  
Solid Hardness ◽  
Rockfill Materials ◽  
Materials Used ◽  
Creep And Stress Relaxation ◽  
Long Term Behavior

For the long-term behavior and safety assessment of rockfill dams, not only the shape of the dam body, the loading history, the geological condition of the dam foundation and abutments, the assessment of possible seismic hazards and seepage events caused by defects of the sealing are important, but also the time dependent mechanical behavior of the dam materials used can be of significant influence. In this paper a novel hypoplastic constitutive model for moisture sensitive, coarse-grained rockfill materials is presented. In the constitutive equations, the so-called solid hardness is a key parameter to reflect the influence of the state of weathering on the mechanical response. With respect to the evolution equation for the solid hardness, creep and stress relaxation can be modeled for dry and wet states of the material in a unified manner. The performance of the model is demonstrated by comparing the numerical simulation with experimental data.

scholarly journals Long-Term Sea Level Cycle Affects Predictions of Future Rise

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Sarah Stanley
Keyword(s):  
Sea Level ◽  
Earth’S Core ◽  
Earth's Core ◽  
New Research ◽  
Term Fluctuation

New research confirms the existence of a regular, long-term fluctuation in sea level, perhaps caused by processes in Earth’s core.

Pedro Miguel Fault Investigations: Borinquen Dam 1e Construction and the Panama Canal Expansion

2018 ◽  
Vol 24 (1) ◽  
pp. 39-53 ◽  
Author(s):  
David L. Schug ◽  
Paul Salter ◽  
Christopher Goetz ◽  
Derek Irving
Keyword(s):  
Age Dating ◽  
Panama Canal ◽  
Geologic Mapping ◽  
Fault Rupture ◽  
The South ◽  
Dam Foundation ◽  
Rockfill Dam ◽  
Access Channel ◽  
Panama Canal Expansion ◽  
Complex Faulting

Abstract Borinquen Dam 1E is part of the new Pacific Access Channel (PAC) of the Panama Canal Expansion. The 2.3-km-long zoned rockfill dam forms the navigational channel providing navigation access from the Gaillard Cut to the new Post-Panamax Pacific Locks. A key geologic objective during construction was to confirm locations and activity of faults mapped at the dam during design, namely the Pedro Miguel Fault (PMF) and its suspected newly mapped “main trace.” The design allowed for core and filter widening at the anticipated location of the PMF at the south abutment and at a west branch of the PMF (believed to be the main active trace of the fault) mapped along the dam axis about one-third of the way north from the south abutment. As-built geologic mapping revealed complex faulting associated with the PMF crossing the southeast half of the foundation, the PAC, and the nearby Dam 1W foundation along a north-south trend. Trenching and age dating of alluvium overlying the faults crossing the Dam 1E foundation and overlying the PMF at Dam 1W indicated the unfaulted alluvium was latest Pleistocene to early Holocene age. At Dam 1E, the core and filters were widened to accommodate potential fault rupture on the PMF and a previously unrecognized fault revealed across the width of the dam foundation. The west branch of the PMF (trenched and mapped during design investigations) was determined to not exist at Dam 1E based on mapping the dam foundation and other extensive excavations created for the PAC.

Numerical Analysis of Keddara Dam under Seismic Motion

2018 ◽  
Vol 40 ◽  
pp. 47-62
Author(s):  
Samia Louadj ◽  
Ramdane Bahar ◽  
Nasser Laouami
Keyword(s):  
Numerical Analysis ◽  
Seismic Event ◽  
Dominant Frequency ◽  
Lagrangian Analysis ◽  
Maximum Acceleration ◽  
Low Coherence ◽  
Seismic Motion ◽  
Rockfill Dam ◽  
Seismic Amplification ◽  
Boumerdes Earthquake

The Boumerdes earthquake of May 21, 2003 in Algeria, which widely felt within a radius of ~ 400 km, caused damage in five provinces. Numerous structures have been devastated, others suffered of damages. Keddara rockfill dam which is situated approximately at 20 km from the epicentre was strongly shaken during this seismic event and can undergo significant deformations. In this study, numerical analysis of Keddara rockfill dam under Boumerdes earthquake is performed. It is mainly focus on the seismic amplification at different level of the dam under the main shock with dominant frequency close to the natural frequency of the dam. The low coherence between the input and the structural output indicates the need of nonlinear analysis of the dam under the spatial variation in excitation. Furthermore, the effect of plasticity on the seismic response is investigated by using maximum acceleration which is one of the most important properties selected. The analysis of the dam under stochastic non-uniform excitation is conducted using a 2-D finite difference modeling by using the software Fast Lagrangian Analysis of Continua (FLAC). The final results obtained after successive analyses on the dam configuration incorporating the nonlinear soil properties are presented.

Covariates of the Long-term Fluctuation of the Differential Light Threshold

1984 ◽  
Vol 102 (6) ◽  
pp. 880-882 ◽  
Author(s):  
J. Flammer ◽  
S. M. Drance ◽  
M. Schulzer
Keyword(s):  
Term Fluctuation
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