9781439834220.ch10

141 fig 1010 or it can be advanced within self

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Unformatted text preview: 20–25 When ground conditions require, roadheader can be mounted inside shields (section 10.14.1, fig. 10.10), or it can be advanced within self-advancing powered supports. The roadheader can move independently within a shield; and the operations such as: excavation, mucking and erection of segmental lining can proceed concurrently. 10.9 HYDRAULIC IMPACT HAMMER TUNNELING Use of hydraulic impact hammers for full face tunneling (fig. 10.7) is rather a new innovation and began during 1960s. In Italy number of tunnels have been driven using © 2005 by Taylor & Francis Group, LLC 246 SURFACE AND UNDERGROUND EXCAVATIONS Conveyor Hammer attachment Loading apron (gathering head) Figure 10.7 Hammer Tunneler with loading and conveying system for excavation of narrow tunnels. this technique;13 and it has proven to be economical in Asia and Mediterranean countries.5 In this technique a 3000 kg (Usual range 2000–3500 kg, or even over)5 hydraulic hammer with impact energy of around 6000 Joules (the range...
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