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1.
Irregular wave-induced mud fluidization and wave spectrum transformation on muddy profiles are studied through representative wave technique. The constitutive equations of visco-elastic model are adopted for the rheological behavior of fluid mud, while the behavior of stationary mud is assumed to be elastic. A set of representative waves are employed to investigate wave–mud interaction. The results are verified using real field data. Comparing the performance of common representative waves, it is concluded that the phenomena can be better predicted by root mean square wave. 相似文献
2.
S. Lovati M. K. H. Bakavoli M. Massa G. Ferretti F. Pacor R. Paolucci E. Haghshenas M. Kamalian 《Bulletin of Earthquake Engineering》2011,9(6):1987-2005
In the present work the seismic site response of Narni ridge (Central Italy) is evaluated by comparing experimental results
and numerical simulations. The inhabited village of Narni is located in central Apennines at the top of a steep massive limestone
ridge. From March to September 2009 the site was instrumented with 10 weak-motion stations, 3 of which located at the base
of the ridge and 7 at the top. The velocimetric network recorded 642 events of ML up to 5.3 and hypocentral distance up to about 100 km. The great amount of data are related to the April 2009 L’Aquila sequence.
The site response was analyzed using both reference (standard spectral ratio, SSR) and non reference spectral techniques (horizontal
to vertical spectral ratio, HVSR). Moreover directional analyses were performed in order to evaluate the influence of the
ridge orientation with respect to the selected source-site paths. In general the experimental results show amplification factors
for frequencies between 4 and 5 Hz for almost all stations installed along the crest. The SSR technique provides amplification
factors up to 4.5 in a direction perpendicular to the main elongation of the ridge. The results obtained from the data analyses
were used as a target for bidimensional and tridimensional numerical simulations, performed using a hybrid finite-boundary
element method and a boundary element method for 2D and 3D modelling, respectively. In general, the results obtained through
numerical simulation fit well the experimental data in terms of range of amplified frequencies, but they underestimate by
a factor of about 2 the observed amplifications. 相似文献
3.
Mahshid Kamrooz Ghader Sarmad Shamsnia S. Hadi Haghshenas S. Abbas 《Ocean Dynamics》2022,72(9-10):715-730
Ocean Dynamics - The present study aims to provide a straightforward analytical solution to wave-current-mud interaction by considering the mean shear stress effects in the water layer. A direct... 相似文献
4.
Boundary-Layer Meteorology - The magnitude of the entrainment buoyancy flux, and hence the growth rate of the convective boundary layer, does not increase monotonically with wind shear.... 相似文献
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6.
Christopher J. Jablonowski Arash Haghshenas Edward E. Shumilak Kenneth F. Tyler 《Natural Resources Research》2017,26(1):57-65
This paper describes the method and results of a probabilistic risk analysis that was used to provide a quantitative basis for a complex and high-stakes design decision for a subsea oil project. Geologic properties were specified as probability density functions based on information from a small number of exploration and appraisal wells. The geological information was coupled to a wellbore fluid dynamics model to simulate operational outcomes for potential well kill operations. Conventional probabilistic sampling and a more efficient experimental design approach were both employed. The key results are cumulative density functions for critical bases of design that are used for risk analysis and final equipment selection. The analysis reinforces the importance of interdisciplinary collaboration, in this case the subsurface disciplines and well engineering, to achieve efficient risk-based designs. 相似文献
7.
Mohammad Khandan Bakavoli Ebrahim Haghshenas Mohsen Kamalian 《Soil Dynamics and Earthquake Engineering》2011,31(5-6):737-756
Two hilly sites were selected to study seismic site response due to topography effects. The sites were selected in a manner to be as much as possible homogenous and free of the soft soil layers effects. The hills were instrumented by nine velocimetric stations to record microtremors and the obtained data were analyzed using horizontal to vertical spectral ratios. Some standard spectral ratio tests were performed on noise as well. Then the instrumented hills were modeled (both 2D and 3D) assuming a linear elastic constitutive behavior subjected to vertically propagating SV and P Ricker wavelets. All calculations were performed in time domain using direct boundary element method. Different transfer function components, amplification patterns and spectral ratios were calculated in frequency domain. The frequency of vibration, obtained by experimental studies, is between 4 and 5 Hz for both of the hills. The spectral ratios derived by numerical simulations were compared with the observed spectral ratios. They show relatively good similarities between the results of these two methods. The frequencies of vibration derived from different methods seem to be nearly identical. The agreement in term of resonance frequency between microtremors and numerical modeling suggests that noise measurements could represent a simple, even if preliminary, tool in order to identify possible topographic amplification. 相似文献
8.
Effects of non-rigid muddy bed on the wave climate at the Hendijan coast along the northwestern part of the Persian Gulf have been examined through field measurements and numerical wave transformation modeling. The field survey included measurements of wave characteristics at an offshore and a nearshore station, and mud sampling to obtain the thickness of the fluid mud layer and its rheological properties. Comparisons of wave spectra at the two stations show energy dissipation along the wave trajectory with higher dissipation in the wave period band around 6?s, because depending on the site a given frequency band tends to be more effective in wave–mud interaction. Dissipation induced by the non-rigid bed is introduced into the REF/DIF wave transformation model through the application of viscoelastic constitutive equations for fluid mud. Numerical outputs of the nearshore wave height, for which the viscoelastic parameters included in the model were obtained independently from oscillatory frequency-sweep tests, are found to be comparable with measured values at the nearshore station. This implies that the model is useful for estimating the design wave conditions in the study area. 相似文献
9.
Natural Hazards - Tunneling projects are generally complex projects with numerous affective factors, including variable and unreliable conditions of the land. One of the appropriate tools for... 相似文献
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Akbarzadeh Mohammadreza Shaffiee Haghshenas Sina Jalali Seyed Mohammad Esmaeil Zare Shokrollah Mikaeil Reza 《Geotechnical and Geological Engineering》2022,40(9):4685-4703
Geotechnical and Geological Engineering - Using the tunnel boring machine (TBM) in tunneling projects contributes significantly to increased efficiency and reducing the time of project... 相似文献