Hydrofraise technology

Execution of diaphragm walls with hydrofraise Definition of hydrofraise A hydrofraise is a reverse circulation excavation tool which consists of a heavy steel frame with two drive gears attached to its bottom end, which rotate in opposite direction round horizontal axes. Cutter wheels area mounted onto the drive gears. As they rotate, the soil beneath the cutter is continuously removed, broken up, mixed with the bentonite slurry in the trench and moved towards the opening … Read more

Secant Pile Wall at a Metro Station

David Moloney Underground Metro Station constructed using Secant Piles. A secant pile wall is constructed using intersecting cast in-situ bored piles. Soft Piles do not have reinforcement, are constructed firstly alternatingly. Hard piles that have reinforcement are constructed between and are cut into the soft piles. The secant pile wall forms an underground retaining wall that will support the faces of excavation and hold back the ground water.

Large Underground Excavated Caverns

Rocscience Inc. The stability of large excavated caverns for underground powerhouses, metro stations and other facilities require careful design as well as precisely sequenced excavation and support installation. The most significant steps in the design and construction process are discussed in this lecture, by Dr. Evert Hoek. See the video on YouTube