Comparative static analysis of tunnelling methods NATM and ADECO-RS

Abstract

New Austrian Tunnelling Method (NATM) has been used almost exlusively in the Czech Republic in the last three decades. This method has many supporters, whose resistance to new methods and approaches prevents the integration of other methods to the tunnelling industry in the Czech Republic. One of the methods thus neglected is the Italian method called ADECO-RS, which has reached significant use also outside Italy. It is a method of controlled deformation, which uses mainly the horizontal anchoring of the tunnel face to reinforce the area in front of the face (advance core). This technology is especially important in weak and soft rocks where it is necessary to excavate quickly and smoothly with minimum disruption of initial stress state of the rock mass in the vicinity of the excavation. It can be assumed that the use of NATM is in some cases uneconomical and technically inadequately challenging and in such cases it would be appropriate to choose another technology. Given the facts above, in the Czech environment there is no data available for comparison of these methods not only in terms of numerical modelling, but also in terms of feasibility and usability.The work briefly summarizes the history of the tunnelling methods and it is closer devoted to NATM and ADECO-RS tunnelling approaches. The basic principles of both methods are set and further the comparison of these methods is made on a theoretical level and in terms of numerical modelling, which was performed in the program PLAXIS 3D-Tunnel. The thesis hereinafter includes the analysis of fibreglass face anchors application during the construction of three-aisled Veleslavín Station and the impact assessment of tunnel face anchoring during the excavation of ventilation tunnel on the newly built part of the Prague Metro "V.A". The work also deals with practical knowledge gained during the technical visit of Italian Val di Sambro tunnel which is built according to ADECO-RS approach. These findings are essential for the correct interpretation of Lunardi method. Finally, the thesis briefly summarize the tunnel construction process by ADECO-RS method.

New Austrian Tunnelling Method (NATM) has been used almost exlusively in the Czech Republic in the last three decades. This method has many supporters, whose resistance to new methods and approaches prevents the integration of other methods to the tunnelling industry in the Czech Republic. One of the methods thus neglected is the Italian method called ADECO-RS, which has reached significant use also outside Italy. It is a method of controlled deformation, which uses mainly the horizontal anchoring of the tunnel face to reinforce the area in front of the face (advance core). This technology is especially important in weak and soft rocks where it is necessary to excavate quickly and smoothly with minimum disruption of initial stress state of the rock mass in the vicinity of the excavation. It can be assumed that the use of NATM is in some cases uneconomical and technically inadequately challenging and in such cases it would be appropriate to choose another technology. Given the facts above, in the Czech environment there is no data available for comparison of these methods not only in terms of numerical modelling, but also in terms of feasibility and usability.The work briefly summarizes the history of the tunnelling methods and it is closer devoted to NATM and ADECO-RS tunnelling approaches. The basic principles of both methods are set and further the comparison of these methods is made on a theoretical level and in terms of numerical modelling, which was performed in the program PLAXIS 3D-Tunnel. The thesis hereinafter includes the analysis of fibreglass face anchors application during the construction of three-aisled Veleslavín Station and the impact assessment of tunnel face anchoring during the excavation of ventilation tunnel on the newly built part of the Prague Metro "V.A". The work also deals with practical knowledge gained during the technical visit of Italian Val di Sambro tunnel which is built according to ADECO-RS approach. These findings are essential for the correct interpretation of Lunardi method. Finally, the thesis briefly summarize the tunnel construction process by ADECO-RS method.