TERMIUM Plus^®

Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 CONT

The intention of presplitting is to attain the same advantages as with smooth blasting. As opposed to smooth blasting, presplitting is used to blast the contour holes before the actual round is fired. Presplitting produces a crack in the rock between the contour holes at which the rock then loosens during the subsequent bench blasting. Because the holes are so closely spaced, crack formation follows the rows of holes and the holes themselves form crack indications. This means that uncharged holes between charged holes can improve the result when so required...  3, record 1, English, - presplitting

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 DEF

Méthode consistant à découper le contour de l'excavation avant l'abattage, en vue d'obtenir un parement précis et régulier [...]  3, record 1, French, - pr%C3%A9d%C3%A9coupage

Record number: 1, Textual support number: 1 OBS

[...] on utilise pour les tirs de mines la technique de prédécoupage : dans la roche on fore verticalement une série de trous de mines. Ceci provoquera une fissure verticale entre le massif de matériau exploité et le terrain qui amortira les ondes de chocs créés par les coups de mines du front de taille.  4, record 1, French, - pr%C3%A9d%C3%A9coupage

Record 1,  Textual support,  Spanish

Record 2,  Textual support,  English

Record number: 2, Textual support number: 1 CONT

Blastholes may be drilled on a regular grid rather than along a single line as in bench blasting and the blastholes may be loaded with small explosive charges designed to loosen rather than fragment the rock. This is called pattern blasting and is commonly applied in opencast coal mines to loosen overburden without disturbing the underlying seam of coal.  1, record 2, English, - pattern%20blasting

Record 2,  Textual support,  French

Record 2,  Textual support,  Spanish

Record 3,  Textual support,  English

Record number: 3, Textual support number: 1 CONT

Since then,...(the heading and bench method)... is used only where the bridge action period of the rock is so short that support is required immediately after blasting and ventilating.  1, record 3, English, - bridge%20action%20period

Record number: 3, Textual support number: 2 CONT

If the bridge action period is too short to permit mucking, it is necessary to ... support the roof prior to mucking. If the bridge action period is long enough to exclude the danger of ... rock falls ..., the support is usually erected from the drill carriage.  1, record 3, English, - bridge%20action%20period

Record number: 3, Textual support number: 1 OBS

Rock Tunneling with Steel Supports, 1977.  1, record 3, English, - bridge%20action%20period

Record 3,  Textual support,  French

Record number: 3, Textual support number: 1 CONT

[...] il existe un délai pendant lequel la paroi de l'excavation reste stable. Ce temps de stabilité décroît quand les dimensions de la cavité augmentent. On adapte donc les dimensions des sections creusées en fonction de ce temps et de celui qui est nécessaire pour stabiliser l'excavation [...]. [...] Si le temps de stabilité est trop court ou nul, on procède soit à une préconsolidation du terrain [...], soit à l'utilisation de machines [...]  1, record 3, French, - temps%20de%20stabilit%C3%A9

Record number: 3, Textual support number: 1 OBS

temps de tenue de terrain: Ouvrages souterrains. Conception - réalisation - entretien, 1988, p. 57.  2, record 3, French, - temps%20de%20stabilit%C3%A9

Record number: 3, Textual support number: 2 OBS

délai d'autoportage; temps d'autoportage : Traité de construction des tunnels, 1970, p. 460.  2, record 3, French, - temps%20de%20stabilit%C3%A9

Record 3,  Textual support,  Spanish