REINFORCED EFFECT OF FLEXIBLE PRE-SUPPORTING METHOD USING A CONTROLLED DRILLING MACHINE FOR SHALLOW SHIELD TUNNELS

Abstract

 Flexible Pre-Supporting method (the Geo-Flex Beams method) was developed for the improvement of safety at the working face during shield construction under the railway or road. This system consists of grout-infused packers developed underground using a controlled drilling machine.
 In this paper, model tests, centrifuge model tests and field loading tests were carried out to verify the effect of reinforced beams. The major results were almost as expected about the effect of prevention of caving-in, deformation control and reinforced mechanism. Moreover, it was confirmed that the reinforced beam provided sufficient strengths such as dead loads and live loads of a road and railway.