| 1. |
- Adamo, Nasrat, et al.
(författare)
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Mystery of Mosul Dam the Most Dangerous Dam in the World : Experts Proposals and Ideas on Mosul Dam
- 2015
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 5:3, s. 79-93
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Tidskriftsartikel (refereegranskat)abstract
- During and after the construction of Mosul Dam, in Iraq, all the studies expressed a clear concern on the fact that the region of the dam suffers from extensive presence of soluble rock formations that might undermine the safety of the dam with its large reservoir. Most of the studies dealt with foundation treatment and safety hazards due to the dissolution of gypsum and anhydrite. To overcome the problem, grouting operations were performed. The seepage of water continued and this highlighted the possibility of the dam failure. Different grouting techniques and methods were suggested but the results were the same. Finally, it was decided to limit the maximum operation water level to EL. 319 m (a.s.l.) instead of EL.330 m (a.s.l.). This recommendation has remained in force up to now with the loss of sizable storage of irrigation water and power potential
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| 2. |
- Adamo, Nasrat, et al.
(författare)
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Mystery of Mosul Dam the most Dangerous Dam in the World : Foundation Treatment during Construction
- 2015
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 5:3, s. 59-69
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Tidskriftsartikel (refereegranskat)abstract
- Mosul dam was constructed on the beds of Fatha Formation (Middle Miocene). The beds of the formation are about 250 m thick composed of Marls, chalky limestone; gypsum, anhydrite, and limestone form a layered sequence. They are highly karstified. As a consequence, plenty of grouting operations were carried out to fill all the cavities, fractures, joints and to stop the seepage under the foundation of the dam. The main grouting operations were Blanket grouting and deep grout curtain. It was necessary to perform an extensive maintenance program to control the seepage process within the grouted zone to stop dissolution of gypsum and protect the safety of the dam.
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| 3. |
- Adamo, Nasrat, et al.
(författare)
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Mystery of Mosul Dam the Most Dangerous Dam in the World : Maintenance Grouting
- 2015
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 5:3, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- Dissolution of gypsum and anhydrite at the foundation of Mosul Dam continued after its construction since 1986 onwards. After impounding, acceptable residual permeability could not be reached and new areas of high grout takes appeared in some other locations. New grout mixes were tested and even methods of delivering and injecting large grout quantities were developed. Sandy mixes were developed by adding certain weight of sand to the cement mix. In addition, pouring gravel after completion of grouting in large takes' zones was performed. As a result of gravel addition, it was concluded that it was not effective and very difficult to pour. Massive grouting was used where bentonite was added to the mix. Piezometric observation was used for checking the conditions of the grout curtain and the detection of problematic areas where additional treatment was required. Massive grouting, however, did not stop the dissolution processes altogether and it seems that it is not likely to do so in the future. The continuation of this program year after year does not preclude some bad implications. More research work is required to improve massive grout durability by adding chemicals which may interact with gypsum beds and hinder dissolution. This can help to improve gypsum resistance and increase its stability. Mathematical models might also be used to understand the mechanism of cavities formation and collapsing.
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| 4. |
- Adamo, Nasrat, et al.
(författare)
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Mystery of Mosul Dam the most Dangerous Dam in the World : Problems Encountered During and after Impounding the Reservoir
- 2015
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 5:3, s. 47-58
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Tidskriftsartikel (refereegranskat)abstract
- Mosul dam was built on the River Tigris northern part of Iraq during the period 25th January, 1981 and finished on 24th July, 1986. The foundation of the dam lies on the Fatha Formation. This formation is composed of alternating beds of marls, limestone, gypsum and clay. The beds of this formation are highly karstified. After impounding, several sinkholes developed within the vicinity of the dam site. The surface expression of the sinkholes suggests that they are caused by underground collapse.The appearance of the downstream sinkholes is most likely related to fluctuations in the tail water level of the main dam during operation of the dam and the downstream regulating reservoir. In addition, water seepage also was noticed in various areas indicating the dissolution of gypsum and anhydrite from the foundation. During the period February-August, 1986 the dissolution intensity ranged from 42 to 80 t /day.
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| 5. |
- Al-Ansari, Nadhir, et al.
(författare)
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Mystery of Mosul Dam the Most Dangerous Dam in the World : Dam Failure and its Consequences
- 2015
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 5:3, s. 95-111
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Tidskriftsartikel (refereegranskat)abstract
- Worries concerning the possibility of the dam failure due to the seepages under the foundation of Mosul Dam during its construction and operation phases enhanced the application of several dam failure models on Mosul Dam case. All the applied models gave similar results. It was noticed through the models that the wave in case of the dam failure will have a height of 54m and the discharge will be of the order of 551000 m3/sec. This wave will reach the capital city of Iraq “Baghdad” after about 38 hours. The discharge of the River Tigris at Baghdad will be 46000m3/sec and the height of the wave will reach 4m. The propagation of the wave along this distance will cause a catastrophe. About 500000 civilians will die in addition to the unbelievable damage that will be caused to the infrastructure of the country.
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| 6. |
- Al-Ansari, Nadhir, et al.
(författare)
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Mystery of Mosul Dam the Most Dangerous Dam in the World : Karstification and Sinkholes
- 2015
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 5:3, s. 33-45
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Tidskriftsartikel (refereegranskat)abstract
- The Fatha (ex-Lower Fars) Formation (Middle Miocene) is the predominant stratigraphic unit in the Mosul Dam area. It is about 250 meters thick near Mosul. Marls, chalky limestone, gypsum, anhydrite, and limestone form a layered sequence of rocks under the foundation of the dam. The foundation of the dam is mainly resting on the Fatha Formation (Middle Miocene) which is highly karstified. Karstic limestone and the development of solution cavities within the gypsum and anhydrite layers are the main geological features under the foundation of the dam. The right (west) abutment is located in the steeply dipping Fatha Formation within Butmah East anticline with SE plunge being in the reservoir north of the dam, whereas the left (east) abutment is located on gently dipping beds of the Fatha Formation, which is overlain by fine clastics of the Injana Formation. These differences in lithology as well the dip amount and direction along both abutments as well upstream and downstream of the dam have certainly affected on the hydraulic pressure and increased the dissolution ability of the gypsum and limestone beds, along the abutments and the foundations, which are already karstified in nearby areas. Consequently, more gypsum, anhydrite and limestone beds are dissolved and karst openings are continuously increasing, as the exerted hydraulic pressure is continuous.First appearance of sinkholes on the right bank down-stream was not until approximately six years after the filling of the reservoir began. The surface expression of the sinkholes suggests that they are caused by an under-ground collapse. Concentric tension cracks appear to have developed around the central void as the sinkholes have developed progressively. Karstification and formation of sinkholes are the most dangerous features threatening the safety of Mosul dam.
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| 7. |
- Al-Ansari, Nadhir, et al.
(författare)
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Mystery of Mosul Dam the most Dangerous Dam in the World : The project
- 2015
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 5:3, s. 15-31
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Tidskriftsartikel (refereegranskat)abstract
- Mosul Dam is an earthfill multipurpose dam. It is located on the River Tigris in northwestern Iraq. The dam is 3.65 km long and its crest elevation is at 341 m above sea level. The storage capacity at normal operation level (330 m above sea level) is 11.11km3. The work to build the dam started on 25thJanuary, 1981 and finished on 24thJuly, 1986. The total cost of the development was estimated at 2.6 billion US$.The foundation of the dam lies on the Fatha Formation. This formation is composed of alternating beds of marls, limestone, gypsum and claystone. It is highly karstified, which has which created a lot of problems during the construction, impounding and operation phases.
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| 8. |
- Al-Ansari, Nadhir, et al.
(författare)
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Nature of the Distributed of the Bed Sediment within Mosul Dam Reservoir, Iraq
- 2013
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Konferensbidrag (refereegranskat)abstract
- Mosul Dam is one of the biggest hydraulic structures in Iraq. It was constructed in 1986 on the Tigris River in the north of Iraq. The initial storage capacity and water surface area of its reservoir reaches 11.11 km3 and 380 km2 respectively at the maximum operation level 330 m a.s.l. The dam was operated in 1986. A total of 56 samples were collected from the bottom of Mosul reservoir covering most of the reservoir area. The results of the analysis of these samples revealed that they were composed of gravel (3.8%), sand (15%), silt (55.5%) and clay (25.7%). The distribution of these sediments indicates that the silt portion represents the highest followed by clay and then sand. However, sand percentages are the highest in the northern zone of the reservoir where the River Tigris enters the reservoir and decreases gradually toward the dam site. In the meantime, silt percentage decreases toward the dam site while the finer fraction (i.e. clay) increases.
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| 9. |
- Al-Ansari, Nadhir, et al.
(författare)
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Sedimentation in the Mosul reservoir of northern Iraq
- 2013
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Ingår i: Journal of Environmental Hydrology. - 1058-3912 .- 1996-7918. ; 21:7, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Mosul Dam is one of the biggest hydraulic structures in Iraq. It was constructed in 1986 on the Tigris River in the north of Iraq for multiple purposes: irrigation, flood control and power generation. The initial storage capacity and water surface area of its reservoir reaches 11.11 km3 and 380 km2 respectively at the maximum operation level 330 m a.s.l. The dam was operated in 1986. Blockage of the intakes of the pump station for North Al-Jazira Irrigation Project in Mosul Dam reservoir has highlighted the importance of sedimentation problems within the reservoir. A total of 56 samples were collected from the bottom of Mosul reservoir covering most of the reservoir area. The results of the analysis of these samples revealed that they were composed of gravel (3.8%), sand (15%), silt (55.5%) and clay (25.7%). The distribution of these sediments indicates that the silt portion represents the highest 77% of the bottom sediments of this reservoir followed by clay (13.5%) and then sand (9.5%). However, sand percentages are the highest in the northern zone of the reservoir where the River Tigris enters the reservoir and decreases gradually toward the dam site. In the meantime, silt percentage decreases toward the dam site while the finer fraction (i.e. clay) increases. Statistically, the average median and mean sizes of the sediments are 2.81 phi (0.142 mm) and 6.1 phi (0.0146 mm) respectively. In addition, the sediments are poorly sorted, nearly symmetrical in skewness and leptokurtic, very leptokurtic, to mesocratic. Finally, it is believed that the geometry and hydrodynamics of the Mosul reservoir, the location of the River Tigris entrance together with the side tributary valleys have played the most important role in the sediments distribution and their characteristics.
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| 10. |
- Issa, Issa E, et al.
(författare)
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Assessment of Sedimentation Characteristics and Capacity Curve for Mosul Dam Reservoir, Iraq
- 2013
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Konferensbidrag (refereegranskat)abstract
- The sedimentation process is the most important problems that affect directly the performance of reservoirs due to the reduction of the storage capacity and possible problems effecting the operation. Thus periodic assessment of the storage capacity and determining sediment deposition patterns is an important issue for operation and management of reservoirs. In this study, bathymetric survey results had been used to assess the characteristics of sedimentation of Mosul Reservoir. It is located on the Tigris River in the north of Iraq. The water surface area of its reservoir is 380 km2 with a designed storage capacity of 11.11 km3 at a maximum operating level (330 m a.s.l). The dam started operating in 1986. No detailed study was yet carried out to assess its reservoir. The present study indicated that the annual sediment deposited in the reservoir is 45.72 × 106 m3year-1 which is divided into 23.2 × 106 and 22.52 × 106 m3year-1 for dead and live zones respectively. This implies the annual reduction rate in the dead and live storage capacities of the reservoir is 0.786% and 0.276% respectively. Furthermore, the stage-storage capacity curves for the future periods (prediction curves) were assessed using 2011 bathymetric survey data.
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