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112.
Roghayeh Shamshiri Mahdi Motagh Marzieh Baes Mohammad Ali Sharifi 《Journal of Geodesy》2014,88(12):1171-1185
This paper presents deformation analysis of Lake Urmia causeway (LUC) embankments in northwest Iran using observations from interferometry synthetic aperture radar (InSAR) and finite element model (FEM) simulation. 58 SAR images including 10 ALOS, 30 Envisat and 18 TerraSAR-X are used to assess settlement of the embankments during 2003–2013. The interferometric dataset includes 140 differential interferograms which are processed using InSAR time series technique of small baseline subset approach. The results show a clear indication of large deformation on the embankments with peak amplitude of \(>\) 50 mm/year in 2003–2010, increasing to \(>\!\!80\) mm/year in 2012–2013 in the line of sight (LOS) direction from ground to the satellite. 2D decomposition of InSAR observations from Envisat and ALOS satellites that overlap in the years 2007–2010 shows that the rate of the vertical settlement and horizontal motion is not uniform along the embankments; Both eastern and western embankments show significant vertical motion, while horizontal motion plays a more significant role in eastern embankment than western embankment. The InSAR results are then used to simulate deformation using FEM at two cross-sections at the distance of 4 and 9 km from the most western edge of the LUC for which detailed stratigraphy data are available. Results suggest that consolidation due to dissipation of excess pore pressure in embankments can satisfactory predict settlement of the LUC embankments. Our numerical modeling indicates that nearly half of the consolidation since the construction time of the causeway 30 years ago has been done. 相似文献
113.
AbstractIn onshore and offshore fields of ocean engineering, piles are used as foundation systems for various structures. Piles are classified into different types depending on their materials, geometries, and particularly, installation methods, which have advantages or limitations. Companies and engineers have developed a new group of piles, because of necessity to improve their performance in terms of increasing the bearing capacity, reducing impacts of traditional installation procedures, implementing by low- torque power equipment, and utilizing them in widely different ground conditions, including in a marine environment. In the present study, three different models of a new pile with an expander body are introduced to increase the shaft and pile-toe diameters and its self-expansion in the embedment depth under the titles of the Bubble pile (BP), Self-Expanded pile (SEP) and Wing pile (WP). The main subject of this research is to achieve increased bearing capacity, reduced installation effects, and decreased required installation torque. The frustum-confining vessel of Amirkabir University of Technology (FCV-AUT) was employed for this purpose. Up to 14 axial compressive and tensile load tests were carried out on different model piles on sand collected from Anzali shore located on the northern coast of Caspian Sea in Iran, with relative densities of 45% to 50% within FCV-AUT. Comparing the performance of introduced pile with traditional pile corresponding to the same characteristics, the results indicated a significant increase in the axial bearing capacity and reduced disturbance effect of the pile. Also, a lower installation torque of the SE pile was required compared to the helical pile. The test results also demonstrated that the new pile could resist considerable compressive and uplift loads, and could be a possible alternative to traditional piles in the onshore sector. 相似文献
114.
The metapelitic schists of Jandagh or simply Jandagh metapelites can be divided into four groups based on mineral assemblages:
(1) quartz-muscovite schists, (2) quartz-muscovite-biotite schists, (3) garnet-muscovite-chlorite schists, and (4) garnet-muscovite-staurolite
schists. The Jandagh garnet-muscovite-chlorite schists show the first appearance of garnets. These garnets contain 58–76%
almandine, 1–18% spessartine, and 8–20% grossular. Microprobe analysing across the garnets demonstrates an increase in Mg#
from core to rim. This is a feature of the prograde metamorphism of metapelites. Well-preserved garnet growth zoning is a
sign that metapelites were rapidly cooled and later metamorphic phases had no effect here. The appearance of staurolite in
garnet-muscovite-chlorite schists signifies a beginning of the amphibolite facies. The absence of zoning in staurolite suggests
that its formation and growth during prograde metamorphism occurred at a widely spaced isograde. Thermobarometric investigations
show that the Jandagh metapelites were formed within a temperature range of 400–670°C and pressures of 2.0–6.5 kbar. These
results are in agreement with the mineral paragenetic evidence and show the development of greenschist and amphibolite facies
in the area studied. 相似文献
115.
Hamideh Rouhani Tazangi Ataallah Soltani Goharrizi Ebrahim Jahanshahi Javaran 《国际泥沙研究》2021,36(5):637-655
In the current study, the settling, interaction, drafting, kissing, and tumbling of two identical and non-identical circular particles were simulated in a two-dimensional box in shear-thinning, Newtonian, and shear-thickening fluids by using the combined lattice Boltzmann-smoothed profile methods. Furthermore, the drag coefficient of one particle settling for different power-law indexes and Archimedes numbers was calculated. Also, the effect of the diameter ratio of the two particle pairs was considered during settling. The developed method was validated by simulating the settling of one particle and two identical particles in a Newtonian fluid. To consider two non-identical particles, two cases were examined. In Case A, the larger particle was above the smaller one and in the Case B, the smaller particle was above the larger one. The results showed that the two non-identical particles were separated more easily than the identical ones. In the settling of two particles under the same Archimedes number, the drafting and kissing time considerably increased by changing the non-Newtonian fluid behavior from a shear-thinning one to a shear-thickening one. Also, when the larger particle was above the smaller one, the time duration of the kissing stage increased with the decrease in the diameter ratio. 相似文献
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Al-Qadami Ebrahim Hamid Hussein Mustaffa Zahiraniza Shah Syed Muzzamil Hussain Matínez-Gomariz Eduardo Yusof Khamaruzaman Wan 《Natural Hazards》2022,110(1):325-348
Natural Hazards - Vehicles can be easily swept away by floodwaters once the flow velocity and depth reach certain critical limits, with probabilities toward fatality reported to be nearly 50%.... 相似文献