China
Africa
Explore chapters and articles related to this topic
Engineering geology of soft clay
Published in Jay Ameratunga, Sivakugan Nagaratnam, M. Das Braja, Soft Clay Engineering and Ground Improvement, 2021
Quick clays are a specific type of sensitive clay with a shear strength that reduces to close to zero on relatively modest loading. Deposits of quick clay are found in near shore marine and lake settings above the level of the last glacial maximum (i.e. the sea level at the end of the last ice age) in Scandinavian countries, Russia, Canada and some northern parts of the USA (Geertsema 2013). Quick clays are the result of deposition of clay minerals in low-energy environments and saline water, which leads to the formation of electrostatic bindings in the clay deposits between the clay minerals and certain cations. Following weathering and/or leaching processes (depending on the precise environment), an unstable physical structure develops within the clay deposit. Where stresses in the ground change (for example, through erosion or earthquake), the quick clay can undergo a rapid reduction in strength and can lead to issues such as large-scale slope instability (SGI 2004). Figure 2.7 provides a simplified summary of the processes of formation.
Jet grouting application for soft soil tunnels in Norwegian clay
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
Quick clay: Quick clay is a clay that in remolded state has a shear strength cur < 0,5 kPa. It means that the clay will be liquid in its remolded state. Quick clay is a soil with brittle fracture properties. Such properties mean that the clay will get a considerable reduction of strength due to strains larger than strains at maximum strength. As a consequence of this, the presence of quick clay may lead to the risk of having progressive landslides. A progressive landslide may, for example, start with a minor initial landslide that evolves in to a considerably larger landslide. Such landslides may lead to significant consequences for the affected area. It is known that quick clay may occur in Norway, Sweden, Finland, Russia, Canada and Alaska.
Jet grouting application for soft soil tunnels in Norwegian clay
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2019
Quick clay: Quick clay is a clay that in remolded state has a shear strength cur < 0,5 kPa. It means that the clay will be liquid in its remolded state. Quick clay is a soil with brittle fracture properties. Such properties mean that the clay will get a considerable reduction of strength due to strains larger than strains at maximum strength. As a consequence of this, the presence of quick clay may lead to the risk of having progressive landslides. A progressive landslide may, for example, start with a minor initial landslide that evolves in to a considerably larger landslide. Such landslides may lead to significant consequences for the affected area. It is known that quick clay may occur in Norway, Sweden, Finland, Russia, Canada and Alaska.
Experimental investigation of the impact of salinity on Champlain Sea clay
Published in Marine Georesources & Geotechnology, 2021
Jinyuan Liu, Mohammad Afroz, Ali Ahmad
Leaching out of salt from the pore fluid can have a profound impact on the geotechnical properties of sensitive marine clays. Salt leaching upsets the balances of the inter-particle electrical forces and impacts the particle alignment, which in turn causes the instability of the soil structure. Many researchers have investigated the impact of leaching on the geotechnical properties of marine clays. For example, tests were conducted to investigate the impact of leaching on the physical properties of Norwegian marine clay (Skempton and Northey 1952; Bjerrum 1954; Rosenqvist 1966; Torrance 1979). It was found that Norwegian marine clay was transformed into quick clay when the salinity was reduced to a very low value (Skempton and Northey 1952; Bjerrum 1954; Rosenqvist 1966). In Norway, the salt-leaching theory seemed to be a key reason behind the sensitivity of Norwegian marine clay. However, according to Torrance (1979), the reduced salinity is only one of the requirements for the development of high sensitivity of marine clays. The existence of low salinity pore water does not guarantee that high sensitivity will be observed. There are many other factors that influence the sensitivity of Champlain Sea clay, such as the coarseness of the material, the electrokinetic potential, and chemical composition of pore fluid (Penner 1965; Mitchell and Houston 1969; Quigley 1980; Helle and Aagaard 2018).