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Shotcrete is an all-inclusive term for spraying concrete or mortar with either a dry or wet mix process. However, shotcrete may also sometimes be used to distinguish wet-mix from the dry-mix method. The term shotcrete was first defined by the American Railway Engineers Association (AREA) in the early 1930s. [6]
Slurry wall design is undertaken based on bending moment and shear envelope obtained from the stress analysis. In the design of such underground walls, width of the unit is considered as one meter, and the wall is analyzed under plane strain condition. Since the length-to-width ratio of excavations is generally large, plane strain conditions ...
The primary advantages of fibre-reinforced shotcrete are: Addition of steel fibers into the concrete improves the crack resistance (or ductility) capacity of the concrete. Traditional rebars are generally used to improve the tensile strength of the concrete in a particular direction, whereas steel fibers are useful for multidirectional ...
Trapped air will leave voids that allow water to collect and degrade (rust) the steel. Modern practice often includes spraying the mixture at pressure (a technique called shotcrete) or some other method of driving out trapped air. Older structures that have failed offer clues to better practices.
Built on a concrete slab foundation, the residence was constructed by spraying shotcrete onto steel rebar and wire mesh frames over inflated aeronautical balloons. [6] It was built by a company named Fame Homes and designed to resist wildfires and earthquakes. The home's first owners were Tyrone and Norma Thompson and Mrs. Thompson planned to ...
Top-down method: Side support walls and capping beams are constructed from ground level by such methods as slurry walling or contiguous bored piling. Only a shallow excavation is needed to construct the tunnel roof using precast beams or in situ concrete sitting on the walls. The surface is then reinstated except for access openings.
The new Austrian tunneling method (NATM), also known as the sequential excavation method (SEM) or sprayed concrete lining method [1] (SCL), is a method of modern tunnel design and construction employing sophisticated monitoring to optimize various wall reinforcement techniques based on the type of rock encountered as tunneling progresses.
Incremental excavation with a shotcrete circular or elliptical lining; Incremental excavation supported by shotcrete, rock bolts, cable anchors and steel sets or ribs; Shafts can be sunk either dry or for methods such as the caisson method they can be sunk wet.