The Experts below are selected from a list of 852 Experts worldwide ranked by ideXlab platform
Fumio Tatsuoka - One of the best experts on this subject based on the ideXlab platform.
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effects of compaction on soil undrained shear strength deteriorating during undrained cyclic loading and controlling seismic stability of embankment
E3S Web of Conferences, 2019Co-Authors: Antoine Duttine, Fumio Tatsuoka, Kazuhiro UenoAbstract:Effects of compaction on the undrained shear strength of saturated Earth-Fill Dam materials are presented. Poorly and well compacted saturated soils may exhibit undrained shear strengths, respectively, significantly lower and higher than corresponding drained shear strength and this trend is amplified as the undrained strength deteriorates by preceding undrained cyclic loading. These features are implemented in a new simplified seismic analysis to evaluate residual deformation of Earth-Fill Dams. The analysis consists of: 1) a modified Newmark sliding block analysis; and 2) a pseudo-static non-linear FEM analysis, both formulated in a unified framework based on the cumulative Damage concept, total stress Earthquake response analysis and a direct total stress modelling of undrained monotonic and cyclic stress-strain behaviours obtained by triaxial tests. The analysis simulates very well the collapse of an Earth-Fill Dam by the 2011 Off the Pacific Coast of Tohoku Earthquake, Japan, and indicates a substantially higher seismic stability under the same conditions of the newly restored Dam completed in 2017. Paramount effects of soil compaction on the seismic stability of Earth-Filled Dam are demonstrated.
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compacted states and physical properties of soil controlled by the degree of saturation during compaction
E3S Web of Conferences, 2019Co-Authors: Fumio Tatsuoka, Toru MiuraAbstract:For satisfactory performance of soil structures, it is necessary to properly control soil compaction ensuring the physical properties of compacted soil required in design. Usually the dry density ρd and the water content w are controlled in relation to the maximum dry density (ρd)max and the optimum water content wopt determined by laboratory compaction tests on a chosen representative sample at a certain compaction energy level CEL. Although CEL and soil type affect significantly (ρd)max , wopt and physical properties, they change inevitably, sometimes largely, in a given project while field CEL may not match the value used in the laboratory compaction tests. In comparison, the optimum degree of saturation (Sr )opt (i.e., Sr when (ρd)max is obtained) and the normalized compaction curve (i.e., ρd/(ρd)max vs. Sr - (Sr )opt relation) for given CEL and soil type are insensitive to variations in CEL and soil type and they are essentially fixed in a given project. Besides, the stress-strain and hydraulic properties of compacted soil are controlled by ρd and “Sr at the end of compaction relative to (Sr )opt ”. It is proposed to control w and CEL so that Sr = (Sr )opt while ρd becomes large enough to ensure the physical properties required in design fully taking advantage of available field CEL on site. A case history of Earth-Fill Dam construction in Japan following this soil compaction control method is reported.
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remedial treatment of soil structures using geosynthetic reinforcing technology
Geotextiles and Geomembranes, 2007Co-Authors: Fumio Tatsuoka, Masaru Tateyama, Yoshiyuki Mohri, Kenichi MatsushimaAbstract:Abstract The advantages of geosynthetic-reinforcing technology to construct new soil structures including; (a) a relatively short construction period; (b) small construction machines necessary; and (c) a higher stability of completed structures, all contributing to a higher cost-effectiveness, are addressed. A number of case successful histories of geosynthetic-reinforced soil retaining walls have been reported in the literature (e.g., [Tatsuoka, F., Koseki, J., Tateyama, M., 1997a. Performance of Earth Reinforcement Structures during the Great Hanshin Earthquake, Special Lecture. In: Proceedings of the International Symposium on Earth Reinforcement, IS Kyushu ‘96, Balkema, vol. 2, pp. 973–1008; Tatsuoka, F., Tateyama, M, Uchimura, T., Koseki, J., 1997b. Geosynthetic-reinforced soil retaining walls as important permanent structures, 1996–1997 Mercer Lecture. Geosynthetics International 4(2), 81–136; Tatsuoka, F., Koseki, J., Tateyama, M., Munaf, Y., Horii, N., 1998. Seismic stability against high seismic loads of geosynthetic-reinforced soil retaining structures, Keynote Lecture. In: Proceedings of the 6th International Conference on Geosynthetics, Atlanta, vol. 1, pp.103–142; Helwany, S.M.B., Wu, J.T.H., Froessl, B., 2003. GRS bridge abutments—an effective means to alleviate bridge approach settlement. Geotextiles and Geomembranes 21(3), 177–196 ; Lee, K.Z.Z., Wu, J.T.H., 2004. A synthesis of case histories on GRS bridge-supporting structures with flexible facing. Geotextiles and Geomembranes 22(4), 181–204 ; Yoo, C., Jung, H.-S., 2004. Measured behavior of a geosynthetic-reinforced segmental retaining wall in a tiered configuration. Geotextiles and Geomembranes 22(5), 359–376 ; Kazimierowicz-Frankowska, K., 2005. A case study of a geosynthetic reinforced wall with wrap-around facing. Geotextiles and Geomembranes 23(1), 107–115 ; Skinner, G.D., Rowe, R.K., 2005. Design and behaviour of a geosynthetic reinforced retaining wall and bridge abutment on a yielding foundation. Geotextiles and Geomembranes 23(3), 234–260 ]). Techniques for analyzing the seismic response of reinforced walls and slopes have also been developed (e.g. Nouri, H. Fakher, A., Jones, C.J.F.P., 2006. Development of horizontal slice method for seismic stability analysis of reinforced slopes and walls. Geotextiles and Geomembranes 24(2),175–187 ). Several typical cases in which embankments having a gentle slope and conventional-type soil retaining walls that were seriously Damaged or failed were reconstructed to geosynthetic-reinforced steepened slopes or geosynthetic-reinforced soil retaining walls are also reported in this paper. It has been reported that the reconstruction of Damaged or failed conventional soil structures to geosynthetic-reinforced soil structures was highly cost-effective in these cases. Rehabilitation of an old Earth-Fill Dam in Tokyo to increase its seismic stability by constructing a counter-balance Fill reinforced with geosynthetic reinforcement is described. Finally, a new technology proposed to stabilize the downstream slope of Earth-Fill Dams against overflowing flood water while ensuring a high seismic stability by protecting the slope with soil bags anchored with geosynthetic reinforcement layers arranged in the slope is described.
Hsiente Chiu - One of the best experts on this subject based on the ideXlab platform.
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seismic response of renyitan Earth Fill Dam
Journal of GeoEngineering, 2009Co-Authors: Meenwah Gui, Hsiente ChiuAbstract:Taiwan is located at one of the Earthquake-active zones. In 1999, a devastating 921 Chi-Chi Earthquake struck Taiwan and caused severe property losses and thousands of lives. Excessive ground deformation caused severe crack to the Shigang concrete Dam and resulted the Dam to completely losses its ability to retain water. As such, assessing the safety of the water Dams on the island has been emphasized. This study assessed the behavior of Renyitan Dam using the acceleration record of Chi-Chi Earthquake obtained some 2 km away as its input acceleration. Dynamic analyses were performed using the dynamic program FLAC^(2D) and results were evaluated from the viewpoint of displacement, excess pore-water pressure, and acceleration generated in the Dam. Numerical results obtained confirmed that the generated excess pore-water pressures during the Chi-Chi Earthquake were insufficient to cause the Dam to liquefy or fail and pin-pointed the most likely location in the Dam where liquefaction would be initiated. Strength improvement to the Dam could be carried out at this weak area.
Kenichi Matsushima - One of the best experts on this subject based on the ideXlab platform.
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remedial treatment of soil structures using geosynthetic reinforcing technology
Geotextiles and Geomembranes, 2007Co-Authors: Fumio Tatsuoka, Masaru Tateyama, Yoshiyuki Mohri, Kenichi MatsushimaAbstract:Abstract The advantages of geosynthetic-reinforcing technology to construct new soil structures including; (a) a relatively short construction period; (b) small construction machines necessary; and (c) a higher stability of completed structures, all contributing to a higher cost-effectiveness, are addressed. A number of case successful histories of geosynthetic-reinforced soil retaining walls have been reported in the literature (e.g., [Tatsuoka, F., Koseki, J., Tateyama, M., 1997a. Performance of Earth Reinforcement Structures during the Great Hanshin Earthquake, Special Lecture. In: Proceedings of the International Symposium on Earth Reinforcement, IS Kyushu ‘96, Balkema, vol. 2, pp. 973–1008; Tatsuoka, F., Tateyama, M, Uchimura, T., Koseki, J., 1997b. Geosynthetic-reinforced soil retaining walls as important permanent structures, 1996–1997 Mercer Lecture. Geosynthetics International 4(2), 81–136; Tatsuoka, F., Koseki, J., Tateyama, M., Munaf, Y., Horii, N., 1998. Seismic stability against high seismic loads of geosynthetic-reinforced soil retaining structures, Keynote Lecture. In: Proceedings of the 6th International Conference on Geosynthetics, Atlanta, vol. 1, pp.103–142; Helwany, S.M.B., Wu, J.T.H., Froessl, B., 2003. GRS bridge abutments—an effective means to alleviate bridge approach settlement. Geotextiles and Geomembranes 21(3), 177–196 ; Lee, K.Z.Z., Wu, J.T.H., 2004. A synthesis of case histories on GRS bridge-supporting structures with flexible facing. Geotextiles and Geomembranes 22(4), 181–204 ; Yoo, C., Jung, H.-S., 2004. Measured behavior of a geosynthetic-reinforced segmental retaining wall in a tiered configuration. Geotextiles and Geomembranes 22(5), 359–376 ; Kazimierowicz-Frankowska, K., 2005. A case study of a geosynthetic reinforced wall with wrap-around facing. Geotextiles and Geomembranes 23(1), 107–115 ; Skinner, G.D., Rowe, R.K., 2005. Design and behaviour of a geosynthetic reinforced retaining wall and bridge abutment on a yielding foundation. Geotextiles and Geomembranes 23(3), 234–260 ]). Techniques for analyzing the seismic response of reinforced walls and slopes have also been developed (e.g. Nouri, H. Fakher, A., Jones, C.J.F.P., 2006. Development of horizontal slice method for seismic stability analysis of reinforced slopes and walls. Geotextiles and Geomembranes 24(2),175–187 ). Several typical cases in which embankments having a gentle slope and conventional-type soil retaining walls that were seriously Damaged or failed were reconstructed to geosynthetic-reinforced steepened slopes or geosynthetic-reinforced soil retaining walls are also reported in this paper. It has been reported that the reconstruction of Damaged or failed conventional soil structures to geosynthetic-reinforced soil structures was highly cost-effective in these cases. Rehabilitation of an old Earth-Fill Dam in Tokyo to increase its seismic stability by constructing a counter-balance Fill reinforced with geosynthetic reinforcement is described. Finally, a new technology proposed to stabilize the downstream slope of Earth-Fill Dams against overflowing flood water while ensuring a high seismic stability by protecting the slope with soil bags anchored with geosynthetic reinforcement layers arranged in the slope is described.
Varoujan K Sissakian - One of the best experts on this subject based on the ideXlab platform.
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Mosul Dam: Is it the Most Dangerous Dam in the World?
Geotechnical and Geological Engineering, 2020Co-Authors: Nadhir Al-ansari, Sven Knutsson, Nasrat Adamo, Jan Laue, Varoujan K SissakianAbstract:Mosul Dam is an Earth Fill Dam, with a storage capacity of 11.11 km^3 constructed on highly karstified gypsum beds alternating with marl and limestone. After impounding in 1986, seepage locations were recognized. The Dam situation now indicates that it is in a state of extreme relative risk. If it fails, then 6 million people will be affected and 7202 km^2 area will be flooded. Grouting operations will elongate the life of the Dam but will not solve the problem. Building a protection Dam downstream will be the best measures to secure the safety of the downstream area and its’ population.
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Mosul Dam : Geology and Safety Concerns
Journal of Civil Engineering and Architecture, 2019Co-Authors: Nasrat Adamo, Varoujan K Sissakian, Nadhir Al-ansari, Jan Laue, Sven KnutssonAbstract:Mosul Dam is an Earth Fill Dam located on the River Tigris northern part of Iraq. The capacity of its reservoir is 11.11 billion cubic meters which makes it the fourth biggest Dam in the Middle Eas ...
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Mosul Dam: A Catastrophe Yet to Unfold
Engineering, 2017Co-Authors: Nasrat Adamo, Sven Knutsson, Nadhir Al-ansari, Jan Laue, Varoujan K SissakianAbstract:Mosul Dam is multipurpose Earth Fill Dam 3.4km long, 113m in height and its storage capacity reaches 11.11 km3 of which 2.95 km3 dead storage. The Dam is located on the River Tigris in the northern ...
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karstification effect on the stability of mosul Dam and its assessment north iraq
Engineering, 2014Co-Authors: Varoujan K Sissakian, Nadhir Alansari, Sven KnutssonAbstract:Mosul Dam is located on the Tigris river, 50 Km NW of Mosul; it is 113 m in height, 3.4 Km in length, 10 m wide in its crest and has a storage capacity of 11.1 billion cubic meters. It is an Earth Fill Dam, constructed on bedrocks of Fat’ha Formation, which consists of gypsum beds alternated with marl and limestone, in cyclic nature. The thickness of gypsum beds attains 18 m; they are intensely karstified even in foundation rocks. Therefore, continuous grouting Programme was planned during construction, which was completed in June 1984, with planned operation age of 80 years. Due to insufficient grouting in the foundation, during last years of the last century, the Karstification was enlarged in size and quantity, causing serious problems to the stability of the Dam. Since late eighties of the last century, the status of the Dam and its probable collapse has caused a panic to the people of Mosul city and near surroundings. Therefore, many attempts were carried out for assessment of the Dam; all of them concluded that the Karstification is the main problem and recommended continuous grouting, using modern techniques. In addition, the authorities started to build another “Badush Dam” south of Mosul Dam so that it can stop the first wave if Mosul Dam if collapsed. All geophysical and geological work executed on the Dam site; it concluded that the existence of many weaknesses zones, faults and large karstified areas, in different parts of the Dam site.
Meenwah Gui - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Two Water Storage Functions of Soil on Pore-Water Pressure of Earth-Filled Dam under Changing Environment
28th International Symposium on Automation and Robotics in Construction (ISARC 2011), 2011Co-Authors: Meenwah GuiAbstract:Seepage of water through Earth Fill Dam involves both the saturated and unsaturated flows of water. Unsaturated flow of water is often neglected because of the complexity required in solving the non-linear partial differential equation involved. This paper presents a seepage analysis of water flows through the partially saturated Renyi-Tan Earth Fill Dam in Taiwan. The governing non-linear partial differential flow equation together with equations representing the characteristics of Dam materials was solved using a PDE solver. Two water storage functions, which were derived by differentiating the van Genuchten (1980) and Leong and Rahardjo (1997)’s SWCC functions, have been used, and the two sets of results obtained have been compared for their sensitivity in seepage analysis of the study Dam.
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seismic response of renyitan Earth Fill Dam
Journal of GeoEngineering, 2009Co-Authors: Meenwah Gui, Hsiente ChiuAbstract:Taiwan is located at one of the Earthquake-active zones. In 1999, a devastating 921 Chi-Chi Earthquake struck Taiwan and caused severe property losses and thousands of lives. Excessive ground deformation caused severe crack to the Shigang concrete Dam and resulted the Dam to completely losses its ability to retain water. As such, assessing the safety of the water Dams on the island has been emphasized. This study assessed the behavior of Renyitan Dam using the acceleration record of Chi-Chi Earthquake obtained some 2 km away as its input acceleration. Dynamic analyses were performed using the dynamic program FLAC^(2D) and results were evaluated from the viewpoint of displacement, excess pore-water pressure, and acceleration generated in the Dam. Numerical results obtained confirmed that the generated excess pore-water pressures during the Chi-Chi Earthquake were insufficient to cause the Dam to liquefy or fail and pin-pointed the most likely location in the Dam where liquefaction would be initiated. Strength improvement to the Dam could be carried out at this weak area.
