As a result of a sustained drought in the Southwestern United States, and in order to maintain existing water capacity in the Las Vegas Valley, the Southern Nevada Water Authority constructed a new deep- water intake ...As a result of a sustained drought in the Southwestern United States, and in order to maintain existing water capacity in the Las Vegas Valley, the Southern Nevada Water Authority constructed a new deep- water intake （Intake No. 3） located in Lake Mead. The project included a 185 m deep shaft, 4.7 km tunnel under very difficult geological conditions, and marine works for a submerged intake. This paper presents the experience that was gained during the design and construction and the innovative solutions that were developed to handle the difficult conditions that were encountered during tunneling with a dual- mode slurry tunnel-boring machine （TBM） in up to 15 bar （l bar = l0s Pa） pressure. Specific attention is given to the main challenges that were overcome during the TBM excavation, which included the mode of operation, face support pressures, pre-excavation grouting, and maintenance; to the construction of the intake, which involved deep underwater shaft excavation with blasting using shaped charges; to the construction of the innovative over 1200 t concrete-and-steel intake structure; to the placement of the intake structure in the underwater shaft; and to the docking and connection to an intake tunnel excavated by hybrid TBM.展开更多
This paper presents a new perspective for engineers when planning, designing, and managing transportation systems-as well as for those restoring and replacing ageing infrastructure. It provides evidence on how taking...This paper presents a new perspective for engineers when planning, designing, and managing transportation systems-as well as for those restoring and replacing ageing infrastructure. It provides evidence on how taking a ＂human＂ approach to trans- port will enable engineers to find smarter ways to move people and goods across cities, countries, and continents. Human-cen- tered mobility puts the user directly at the heart of design and decision making. By adopting this approach, we can create effi- cient and resilient transport solutions that are mutually beneficial for both passengers and operators and which shape better cities and communities.展开更多
文摘As a result of a sustained drought in the Southwestern United States, and in order to maintain existing water capacity in the Las Vegas Valley, the Southern Nevada Water Authority constructed a new deep- water intake （Intake No. 3） located in Lake Mead. The project included a 185 m deep shaft, 4.7 km tunnel under very difficult geological conditions, and marine works for a submerged intake. This paper presents the experience that was gained during the design and construction and the innovative solutions that were developed to handle the difficult conditions that were encountered during tunneling with a dual- mode slurry tunnel-boring machine （TBM） in up to 15 bar （l bar = l0s Pa） pressure. Specific attention is given to the main challenges that were overcome during the TBM excavation, which included the mode of operation, face support pressures, pre-excavation grouting, and maintenance; to the construction of the intake, which involved deep underwater shaft excavation with blasting using shaped charges; to the construction of the innovative over 1200 t concrete-and-steel intake structure; to the placement of the intake structure in the underwater shaft; and to the docking and connection to an intake tunnel excavated by hybrid TBM.
文摘This paper presents a new perspective for engineers when planning, designing, and managing transportation systems-as well as for those restoring and replacing ageing infrastructure. It provides evidence on how taking a ＂human＂ approach to trans- port will enable engineers to find smarter ways to move people and goods across cities, countries, and continents. Human-cen- tered mobility puts the user directly at the heart of design and decision making. By adopting this approach, we can create effi- cient and resilient transport solutions that are mutually beneficial for both passengers and operators and which shape better cities and communities.
