87144. 34231. 87110. 34231. 87144. 32220. 87110. Complete OFO Version 2017 OFO Code Description 2017-1 MANAGERS Managers plan, direct, coordinate and evaluate the overall activities of enterprises, governments and other organizations, or of organizational units within them, and formulate and review their policies, laws, rules and regulations.
The first successful tunnelling shield was developed by Sir Marc Isambard Brunel to excavate the Thames Tunnel in 1825. However, this was only the invention of the shield concept and did not involve the construction of a complete tunnel boring machine, the digging still having to be accomplished by the then standard excavation methods.
This paper outlines methods for estimating the jacking forces associated with different types of microtunnelling operations. These methods have been developed using probably the most extensive database of microtunnelling jacking forces assembled to date.