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Rock Bolt
A rock bolt is a long anchor bolt, for stabilizing rock excavations, which may be used in tunnels or rock cuts. It transfers load from the unstable exterior to the confined (and much stronger) interior of the rock mass. Rock bolts were first used in mining in the 1890s, with systematic use documented at the St Joseph Lead Mine in the U.S. in the 1920s. Rock bolts were applied to civil tunneling support in the U.S. and in Australia starting in the late 1940s. Rock bolts were used and further developed starting in 1947 by Australian engineers who began experimenting with four-meter-long expanding anchor rock bolts while working on the Snowy Mountains Scheme. As shown in the figure, rock bolts are almost always installed in a pattern, the design of which depends on the Core recovery parameters#Rock quality designation, rock quality designation and the type of excavation. Rock bolts are an essential component of the New Austrian Tunneling method. As with anchor bolts, there are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anchor Bolt
Anchor bolts are used to connect structural and non-structural elements to concrete.. The connection can be made by a variety of different components: anchor bolts (also named fasteners), steel plates, or stiffeners. Anchor bolts transfer different types of load: tension forces and shear forces. A connection between structural elements can be represented by steel columns attached to a reinforced concrete foundation. A common case of a non-structural element attached to a structural one is the connection between a facade system and a reinforced concrete wall. Types Cast-in-place The simplest – and strongest – form of anchor bolt is cast-in-place, with its embedded end consisting of a standard hexagonal head bolt and washer, 90-bend, or some sort of forged or welded flange (see also stud welding). The last are used in concrete-steel composite structures as shear connectors. Other uses include anchoring machines to poured concrete floors and buildings to their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowy Mountains Scheme
The Snowy Mountains Scheme, also known as the Snowy Hydro or the Snowy scheme, is a hydroelectricity and irrigation in Australia, irrigation complex in south-east Australia. Near the border of New South Wales and Victoria (Australia), Victoria, the scheme consists of sixteen major dams; nine power stations; two pumping stations; and of tunnels, pipelines and aqueducts that were constructed between 1949 and 1974. The Scheme was completed under the supervision of Chief Engineer, William Hudson (engineer), Sir William Hudson. It is the largest engineering project undertaken in Australia. The water of the Snowy River and some of its tributary, tributaries, much of which formerly flowed southeast onto the river flats of East Gippsland, and into Bass Strait of the Tasman Sea, is captured at high elevations and diverted inland to the Murray River, Murray and Murrumbidgee Rivers irrigation areas. The Scheme includes two major tunnel systems constructed through the continental divide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core Recovery Parameters
Core recovery parameters describe the quality of core recovered from a borehole. Total core recovery Total core recovery (TCR) is the borehole core recovery percentage. TCR is defined as the quotient: :TCR = \left(\frac\right)\times 100 % :l_\mathrm = Sum of length of core pieces :l_\mathrm = Total length of core run Solid core recovery Solid core recovery (SCR) is the borehole core recovery percentage of solid, cylindrical, pieces of rock core. SCR is defined as the quotient: :SCR = \left(\frac\right)\times 100 % :l_ = Sum of length of solid, cylindrical, core pieces :l_ = Total length of core run Rock quality designation Rock-quality designation (RQD) is a rough measure of the degree of jointing or fracture in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. High-quality rock has an RQD of more than 75%, low quality of less than 50%. Rock quality designation (RQD) has several definitions. The most widely used definition was developed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Austrian Tunneling Method
The new Austrian tunneling method (NATM), also known as the sequential excavation method (SEM) or sprayed concrete lining method (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. This technique first gained attention in the 1960s based on the work of Ladislaus von Rabcewicz, Leopold Müller, and Franz Pacher between 1957 and 1965 in Austria. The name NATM was intended to distinguish it from earlier methods, with its economic advantage of employing inherent geological strength available in the surrounding rock mass to stabilize the tunnel wherever possible rather than reinforcing the entire tunnel. NATM/SEM is generally thought to have helped revolutionise the modern tunneling industry. Many modern tunnels have used this excavation technique. The Sequential Excavation Method is very cost effective, even in karst conditions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Property
Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depending on the nature of the property, an owner of property may have the right to consume, alter, share, rent, sell, exchange, transfer, give away, or destroy it, or to exclude others from doing these things, as well as to perhaps abandon it; whereas regardless of the nature of the property, the owner thereof has the right to properly use it under the granted Property rights (economics), property rights. In economics and political economy, there are three broad forms of property: private property, public property, and collective property (or ''cooperative propert''y). Property may be jointly owned by more than one party equally or unequally, or according to simple or complex agreements; to distinguish ownership and easement from rent, there is an expectation that each party's will with regard to the property be clearly defined and unconditional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoxy
Epoxy is the family of basic components or Curing (chemistry), cured end products of epoxy Resin, resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also collectively called ''epoxy''. The IUPAC name for an epoxide group is an oxirane. Epoxy resins may be reacted (cross-linked) either with themselves through catalytic homopolymerisation, or with a wide range of co-reactants including polyfunctional amines, acids (and acid anhydrides), phenols, alcohols and thiols (sometimes called mercaptans). These co-reactants are often referred to as hardeners or curatives, and the cross-linking reaction is commonly referred to as Curing (chemistry), curing. Reaction of polyepoxides with themselves or with polyfunctional hardeners forms a thermosetting polymer, often with favorable mechanical properties and high thermal and chemical resistance. Epoxy has a wide range of application ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiberglass
Fiberglass (American English) or fibreglass (English in the Commonwealth of Nations, Commonwealth English) is a common type of fibre-reinforced plastic, fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth. The plastic Matrix (composite), matrix may be a thermoset polymer matrix—most often based on thermosetting polymers such as epoxy, polyester resin, or vinyl ester resin—or a thermoplastic. Cheaper and more flexible than Carbon-fiber-reinforced polymers, carbon fiber, it is stronger than many metals by weight, non-magnetic, non-conductive, transparent to electromagnetic radiation, can be molded into complex shapes, and is chemically inert under many circumstances. Applications include aircraft, boats, automobiles, bath tubs and enclosures, swimming pools, hot tubs, septic tanks, water tanks, roofing, pipes, cladding, orthopedic casts, surfboards, and external door skins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big Dig (Boston, Massachusetts)
The Big Dig was a megaproject in Boston that rerouted the then elevated Central Artery of Interstate 93 that cut across Boston into the O'Neill Tunnel and built the Ted Williams Tunnel to extend Interstate 90 to Logan International Airport. Those two projects were the origin of the official name, the Central Artery/Tunnel Project (CA/T Project). The project constructed the Zakim Bunker Hill Bridge over the Charles River, created the Rose Kennedy Greenway in the space vacated by the previous I-93 elevated roadway, and funded more than a dozen projects to improve the region's public transportation system. Planning for the project began in 1982. Construction work was carried out between 1991 and 2006. The project concluded in December 2007. The project's general contractor was Bechtel, with Parsons Brinckerhoff as the engineers, who worked as a consortium, both overseen by the Massachusetts Highway Department. The Big Dig was the most expensive highway project in the United S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rockfall
A rockfall or rock-fallWhittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984. . is a quantity of Rock (geology), rock that has fallen freely from a cliff face. The term is also used for collapse of rock from roof or walls of mine or quarry workings. A rockfall is "a fragment of rock (a block) detached by sliding, toppling, or falling, that falls along a vertical or sub-vertical cliff, proceeds down slope by bouncing and flying along ballistic trajectories or by rolling on talus or debris slopes". Alternatively, a rockfall is "the natural downward motion of a detached block or series of blocks with a small volume involving free falling, bouncing, rolling, and sliding". The mode of failure differs from that of a rockslide. Causal mechanisms Favourable geology and climate are the principal causal mechanisms of rockfall, factors that include intact condition of the rock mass, discontinuities within the rockmass, weathering susceptibility, ground and surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zen And The Art Of Rockbolting
Zen (; from Chinese: ''Chán''; in Korean: ''Sŏn'', and Vietnamese: ''Thiền'') is a Mahayana Buddhist tradition that developed in China during the Tang dynasty by blending Indian Mahayana Buddhism, particularly Yogacara and Madhyamaka philosophies, with Chinese Taoist thought, especially Neo-Daoist. Zen originated as the Chan School (禪宗, ''chánzōng'', 'meditation school') or the Buddha-mind school (佛心宗'', fóxīnzōng''), and later developed into various sub-schools and branches. Chan is traditionally believed to have been brought to China by the semi-legendary figure Bodhidharma, an Indian (or Central Asian) monk who is said to have introduced dhyana teachings to China. From China, Chán spread south to Vietnam and became Vietnamese Thiền, northeast to Korea to become Seon Buddhism, and east to Japan, becoming Japanese Zen. Zen emphasizes meditation practice, direct insight into one's own Buddha nature (見性, Ch. ''jiànxìng,'' Jp. ''kenshō''), and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
