Trench shoring — is the process of bracing the walls of a trench in order to prevent collapse. The phrase can also be used as a noun to refer to the materials used in the process.Several methods can be used to shore up a trench. Hydraulic shoring is the use of… … Wikipedia
MacAdam Shield Shovel — The MacAdam Shield Shovel, also known as the Hughes Shovel, was an item of Canadian infantry equipment designed at the beginning of the First World War. It was conceived and patented by Sam Hughes, the Canadian minister for the Department of… … Wikipedia
Mobile personnel shield — Mobile personnel shield. Mobile personnel shield (interior). A … Wikipedia
37 mm trench gun M1915 — Infobox Weapon name=37 mm trench gun M1915 caption= origin= type=infantry support gun is ranged= is bladed= is explosive= is artillery=yes is vehicle= is UK= service= used by= wars= designer= design date= manufacturer= production date= number=… … Wikipedia
Retaining wall — A retaining wall is a structure that holds back soil or rock from a building, structure or area. Retaining walls prevent downslope movement or erosion and provide support for vertical or near vertical grade changes. Cofferdams and bulkheads,… … Wikipedia
tunnels and underground excavations — ▪ engineering Introduction Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening … Universalium
Opportunity rover — (MER B) Opportunity in April 2003 Operator NASA Mission type Rover … Wikipedia
Pacific Ring of Fire — The Ring of Fire redirects here. For other uses of the term, see Ring of Fire (disambiguation). The Pacific Ring of Fire (see below) … Wikipedia
North America — North American. the northern continent of the Western Hemisphere, extending from Central America to the Arctic Ocean. Highest point, Mt. McKinley, 20,300 ft. (6187 m); lowest, Death Valley, 276 ft. (84 m) below sea level. 400,000,000 including… … Universalium
Precambrian time — Interval of geologic time from с 3. 8 billion years ago, the age of the oldest known rocks, to 544 million years ago, the beginning of the Cambrian Period. This interval represents more than 80% of the geologic record and thus provides important… … Universalium
