scholarly journals Assessing the Vertical Displacement of the Grand Ethiopian Renaissance Dam during its Filling using DInSAR technology and its Potential Acute Consequences on the Downstream Countries

2021 ◽  
Author(s):  
Hesham El-Askary ◽  
Amr Fawzy ◽  
Rejoice Thomas ◽  
Wenzhao Li ◽  
Nicholas LaHaye ◽  
...  
Keyword(s):  
Vertical Displacement ◽  
The Body ◽  
The West ◽  
West Side ◽  
Total Displacement ◽  
Vertical Displacements ◽  
Water Edge ◽  
Sar Imagery ◽  
Under Construction ◽  
Weak Zones

The Grand Ethiopian Renaissance Dam (GERD), formerly known as the Millennium Dam, is currently under construction and has been filling at a fast rate without sufficient known analysis on possible impacts on the body of the structure. The filling of GERD not only has an impact on the Blue Nile Basin hydrology, water storages and flow but also pose massive risks in case of collapse. Rosaries Dam located in Sudan at only 116 km downstream of GERD, along with the 20 million Sudanese benefiting from that dam, would be seriously threatened in case of the collapse of GERD. In this study, through the analysis of Sentinal-1 satellite imagery we show concerning deformation patterns associated with different sections of the GERD’s Main Dam (structure RCC Dam type) and the Saddle Dam (Embankment Dam type). We processed 109 descending mode scenes from Sentinel-1 SAR imagery, from December 2016 to July 2021, using the Differential Synthetic Aperture Radar Interferometry technique to demonstrate the deformation trends of both - the GERD’s Main and Saddle Dams. The time-series generated from the analysis clearly indicates different displacement trends at various sections of the GERD as well as the Saddle Dam. Results of the multi temporal data analysis on and around the project area show inconsistent subsidence at the extremities of the GERD Main Dam, especially the west side of the dam where we recorded varying displacements in the range of 10 mm to 90 mm at the crest of the dam. We conducted the current analysis after masking the images with a coherence value of 0.9 and hence, the subsequent results are extremely reliable and accurate. Further decomposition of the subsiding rate has revealed higher vertical displacement over the west side of the GERD’s Main Dam as compared to the east side. The local geological structures consisting of weak zones under the GERD’s accompanying Saddle Dam adds further instability to its structure. We identified seven critical nodes on the Saddle Dam that match the tectonic faults lying underneath it, and which display a varying degree of vertical displacements. In fact, the nodes located next to each other displayed varying displacement trends: one or more nodes displayed subsidence since 2017 while the other node in the same section displayed uplift. The geological weak zones underneath and the weight of the Saddle Dam itself may somewhat explain this inconsistency and the non-uniform vertical displacements. For the most affected cells, we observed a total displacement value of ~90 mm during the whole study period (~20 mm/year) for the Main Dam while the value of the total displacement for the Saddle dam is ~380 mm during the same period (~85 mm/year). Analysis through CoastSat tool also suggested a non-uniformity in trends of surface water-edge at the two extremities of the Main Dam.

On a Quartz-porphyry from the Lake District

1924 ◽  
Vol 61 (11) ◽  
pp. 513-515 ◽  
Author(s):  
Sidney Melmore
Keyword(s):  
Igneous Rock ◽  
The Body ◽  
Lake District ◽  
The South ◽  
The West ◽  
Quartz Porphyry ◽  
West Side ◽  
South Side ◽  
The Road

A Small quarry was opened about three years ago at Thwaite Head, which lies between the southern ends of Coniston Lake and Windermere. It is on the west side of the road between that hamlet and Hawkshead, and exposes a nearly vertical sill, 40 feet wide, running E.N.E.-W.S.W. in the Bannisdale slates. On the south side a series of joint-planes running parallel to the bedding of the slates and curving inwards at the top have split the igneous rock into flags, while in the body of the rock the jointing is much coarser, so that it is quarried in large blocks. Both the igneous rock and the slates are much decomposed and friable along the southern junction, and it is here a little galena is said to have been found when the quarry was first opened. This is not improbable, as the old Thwaite Head lead mine is situated not far off on the banks of Dale Park Beck.

Geodetic measurements in the Dixie Valley Area

1957 ◽  
Vol 47 (4) ◽  
pp. 321-325
Author(s):  
C. A. Whitten
Keyword(s):  
Valley Floor ◽  
Similar Amount ◽  
East Side ◽  
The West ◽  
West Side ◽  
Geodetic Measurements ◽  
Vertical Displacements ◽  
Dixie Valley ◽  
Valley Area

abstract Resurveys made after the 1954 earthquake in the Dixie Valley Area determined the horizontal and vertical displacements which occurred. Triangulation stations on the west side of the fault moved north approximately 4 feet, and points on the east side moved south by a similar amount. Releveling showed a drop and also a tilt of a valley floor.

scholarly journals Investigating the vertical displacement of Duhok embankment Dam: A 31- Years Case Study

2021 ◽  
Vol 9 (ICRIE) ◽  
Author(s):  
Sarmad Abdullah M.Salim ◽  
◽  
Sarhat Mustafa Adam ◽  
Keyword(s):  
Vertical Displacement ◽  
Vertical Movement ◽  
Embankment Dam ◽  
The West ◽  
Monitoring Point ◽  
Downward Displacement ◽  
Vertical Displacements ◽  
The City

The paper studies the long-term settlement behaviour of more than 30-year of the Duhok dam. The dam uses as the major lake for water supply to the city of Duhok and nearby areas. High-precision levelling was used to measure the deformation of the dam to monitor vertical displacements. Five survey campaigns were conducted over 30-year duration: 1988, March 1990, June 1999, March 2017 and February 2019. Analysis of the results found that the highest downward displacement of roughly 20.4 cm was witnessed between 1988 and 2019 for a monitoring point (BM24) located centrally along the bank of the dam. On the other hand, the highest vertical movement of roughly 1.5 cm was estimated between 1990 and 2019 at the monitoring point (BM27) on the west side of the dam. The monitoring point (BM24) had the highest average absolute movement of about 6.0 mm (per year) over the 31 years. Detailed results and analyzes are presented in this article.

scholarly journals The Concept of Accuracy Analysis of the Vertical Displacements Gained from the Hydrostatic Levelling Systems’ Measurements

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4842
Author(s):  
Waldemar Kamiński
Keyword(s):  
Accuracy Assessment ◽  
Theoretical Models ◽  
Vertical Displacement ◽  
Serial Connection ◽  
Vertical Displacements ◽  
Comprehensive Determination ◽  
The One ◽  
The Individual ◽  
Reference Sensor

Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the controlled points (CPs). The reference sensor is the one that is placed at the point that (in theoretical assumptions) is not a subject to vertical displacements and the displacements of controlled points are determined according to its height. The hydrostatic levelling rule comes from the Bernoulli’s law. While using the Bernoulli’s principle in hydrostatic levelling, the following components have to be taken into account: atmospheric pressure, force of gravity, density of liquid used in sensors places at CPs. The parameters mentioned above are determined with some mean errors that influence on the accuracy assessment of vertical displacements. In the subject’s literature, there are some works describing the individual accuracy analyses of the components mentioned above. In this paper, the author proposes the concept of comprehensive determination of mean error of vertical displacement (of each CPs), calculated from the mean errors’ values of components dedicated for specific HLS. The formulas of covariances’ matrix were derived and they enable to make the accuracy assessment of the calculations’ results. The author also presented the subject of modelling of vertical displacements’ gained values. The dependences, enabling to conduct the statistic tests of received model’s parameters, were implemented. The conducted tests make it possible to verify the correctness of used theoretical models of the examined object treated as the rigid body. The practical analyses were conducted for two simulated variants of sensors’ connections in HLS. Variant no. I is the sensors’ serial connection. Variant no. II relies on the connection of each CPs with the reference sensor. The calculations’ results show that more detailed value estimations of the vertical displacements can be obtained using variant no. II.

scholarly journals La datation du choeur de l’église de Vaucelles reproduit en plan par Villard de Honnecourt

2018 ◽  
Vol 81 (3) ◽  
pp. 411-417
Author(s):  
Laurence Terrier Aliferis
Keyword(s):  
Nineteenth Century ◽  
Historical Sources ◽  
The West ◽  
West Side ◽  
Villard De Honnecourt ◽  
The Church

Abstract The ruined Cistercian church of Vaucelles is known only by a few preserved fragments and a plan of the choir reproduced by Villard of Honnecourt. Historical sources provide three key dates: 1190 (start of construction), 1215 (entry into the new church), 1235 (date of the dedication). From the nineteenth century until now, it was considered that the foundations were laid in 1190 and that the construction started on the west side of the church. In 1216, the nave would have been completed, and the choir would have been built between 1216 and 1235. Consultation of the historical sources and examination of the historiographic record changes this established chronology of the site. In fact, the construction proceeded from east to west. The choir reproduced in 1216 or shortly before by Villard de Honnecourt presents the building as it then appeared, with the eastern part of the building totally completed.

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