Tunnel Boring Machines

  • Sutcliffe H
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Abstract

Consulting Engineer Tunnel boring machines (TBMs) are used to excavate tunnels in virtually all types of ground and under widely different physical conditions. This chapter covers hard and soft rock TBMs with full-face rotating heads and their development from soft ground shields. Roadheaders (boom headers) are also discussed here because of their growing role in the softer rock tunnels and caverns. The innovative Ranging Mobile Miner, which combines some of the advantages of the roadheader and the TBM and can be used in harder rocks, is also covered. The functions of a TBM are simple enough: • To excavate the ground • To remove the material excavated • To maintain line and grade of the excavation • To support the excavated tunnel temporarily until permanent support can be provided • To handle adverse ground conditions These five simple requirements become less simple when the necessary qualifying conditions are added. The functions must be performed: • Safely • Reliably • Continuously for many months • Through any and all ground conditions • Quickly • Economically Throughout the development of TBMs, a term which implies a rotary action, designers have built on the successes and the failures of their predecessors. In recent years, there has been a great deal of healthy cross-fertilization between designs of machines for hard rock and those for soft ground. Today's TBM is likely to have been designed specifically for the anticipated ground conditions and is likely to use technology from both hard rock and soft ground machines. A TBM is subjected to heavy stress and much abuse during its service life. It is worth reflecting that a typical hard rock TBM may be called upon to cut through a wall of rock considerably larger in area than the wall of an average room, the wall being made up of rock of up to 10 times the strength of normal concrete. It must do this steadily, day and night, for many months, perhaps under corrosively saline water inflows , and almost certainly, at some point, through uncooperative ground. Only the state of the art in metallurgy and mechanical design can create a machine that can accomplish this. HISTORICAL DEVELOPMENT Like many other technical developments, the TBM was designed in concept by men of genius long before the technologies of metallurgy and motive power were advanced sufficiently to meet the challenges the designs imposed. In the period starting in the early 19th century, numerous tun-neling machines were built, largely in the United States and Great Britain, many of them with features that can be recognized in the modem TBM. Before that time, soft ground was excavated and supported by hand mining methods, then from the protection of a shield, then from increasingly mechanized shields. The rock tunnels were excavated by explosives set in holes drilled into the face. Subaqueous tunnels in both rock and soft ground were not attempted until the early 19th century, and the poor success rate led to the development of the shield, and its subsequent mechanization into a TBM. The history of TBMs started with soft ground shields of the type developed by Marc I. BruneI (the senior BruneI) and J.H. Greathead in England. These shields progressed by breaking the excavation into small compartments excavated by hand. The first BruneI shield, patented in 1818, excavated these compartments and advanced the shield in a spiral pattern, with lining segments following in the same spiral. The shield did not rotate, but the spiral arrangement of 203 J. O. Bickel et al. (eds.), Tunnel Engineering Handbook

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APA

Sutcliffe, H. (1996). Tunnel Boring Machines. In Tunnel Engineering Handbook (pp. 203–219). Springer US. https://doi.org/10.1007/978-1-4613-0449-4_11

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