ABSTRACT:

The problem of rock massif deformation during shield tunnelling is analyzed. At the present time the escavation less shield methods belong to the advanced and mostly used methods in construction of communal drifts and tunnels. The disadvantage in dense built-up areas is the deformation of the overburden extending up to the surface. After the brief overview of the shield driven communal tunnels in Slovakia the used measuring method and the obtained results of seven years in situ investigation of overburden settlement are discussed. The evaluation of measurements determined on 16.sites in Bratislava and surrounding is presented. A new calculation method was derived which is suitable for prognostication of overburden deformation in quarternary formations. Finally the basic measures which have to be fulfilled during shield driving are reviewed.

RÉSUMÉ:

L'article s'occupe des problèmes de la deformation du massif de roche qui se produise en perçant des galeries souterraines à l'aide d'un bouclier metallique. Actuellement l'application des methodes de ce percement sans l'excavation à la construction des galeries communales et des tunnels appartiennent aux methodes preferees. Comme leur desavantage dans les localites des villes avec les batiments très serres se produisent les deformations du toit, montantes jusqu'à la surface. L'article donne le precis des galeries souterraines en Slovaquie, percees à l'aide d'un bouclier metallique et decrit le procede du mesurage de 7 ans de 1'affaissement du toit in situ. L'article contient aussi les mesurages evalues des 16 constructions à Bratislava et son environ. De ces mesurages a resulte une nouvelle methode de calcul pour faire des previsions des deformations du toit dans les couverts anthropozoiques. A la fin on mentionne des mesures necessaires contre l'affaissement lesquelles il faut respecter au percement.

RESÜMEE:

lm Beitrag wird das Problem der Deformation der Gesteinmassive beim Bau von Stollen und Tunnels mittels Tunnelschilder analysiert. Die Bauweise mit dem Tunnelschild ist eine moderne, sehr verbreitete Methode. In dicht besiedelten Zonen bedeuten jedoch die Oberflachesetzungen einen grossen Nachteil. Nach einer kurzen Einleitung des Standes die- ser Bauweise in der Slovakei wird die angewandte Messmethode detailiert. Die wahrend der 7-Jahrigen Forschung an 16 Baustellen ermittelten Messungen von Oberflachesetzungen in Bratislava und Umgebung werden charakterisiert und ausgewertet. Auf Grund der Befunde wird eine Rechnungsmethode zwecks Prognosierung von Oberflachesetzungen fuer quartare Dec- kschichtformationen ausgearbeitet. Abschliessend werden die Grundvorkehrungen fuer eine deformationslose Bauweise mittels Tunnelschilder zusammengefasst.

1 INTRODUCTION

In the comparison of tunneling in Slovakia with the worldwide standard can be noticed at there is a difference partly in the extent of underground works application and partly in the technical and economical level; however that implies one another. Meanwhile in industrial countries the field of underground works for various purposes is developing, in our country we are facing the lack of advanced technology and find ourselves in the testing face of new tunneling methods common in the rest of industrial world. Shield tunneling without excavation and jacking methods belong to the most progressive underground transportation and network building methods in urban environmentals. Their major advantage is the minimum disturbance of traffic and of the environment of the town. The building of the underground works by means of techniques without excavation however damages the continuity and the balance of the rock massif. The creation of new balanced state is accompanied by tunnel deformation resulting in overburden settlement. When tunnels and drifts are driven not very deeply and in uncosolidated rock the settlement of the overburden is manifested on the ground surface.

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