Due to diversified topography a number of tunnels have been constructed on Slovenian motorway networkudin the last 15 years after the implementation of the National motorway construction programme. 3Duddisplacement measurements of the primary lining has been applied as an integral part of the observationaludmethod on all tunnel construction sites since the Golovec tunnel construction in 1997. Analysis andudinterpretation of the measured displacements allow the verification of the design parameters, supportudoptimization and optimization of construction processes. Monitoring data from the 13 tunnels, constructedudafter 1998, were collected and arranged in the database in the framework of this thesis together with faceudlogs. Further on, a computer code Predor (means Tunnel in Slovene) was developed for graphicaludpresentation and analysis of these data. Code comprises also a system for automatic handling of theudincoming data from construction sites and for the preparation of graphical reports in real time. The mainudemphasis of the work was given to the analysis of measured displacements in tunnels, situated in softudfoliated rock mass of Carboniferous age (the Trojane, Golovec and Šentvid tunnels). Monitoreduddisplacements display more or less pronounced anisotropic response in the cross section as well as in theudlongitudinal section. To model the observed response, back analyses with numerical calculations suggestedudvery low value of shear modulus along the discontinuities. Special attention was paid to the analysis of welluddocumented longitudinal displacements in the excavation direction under decreasing overburden due toudanisotropy of the rock mass. It was found out that the magnitude of final measured displacements and thusudportion of pre-displacements strongly depends on the relative discontinuity orientation to the tunnel axis. Audlarge number of numerical simulations was performed to define the portion of pre-displacements and theudextent of pre-face domain for different discontinuity orientations and different sets of material properties ofudthe anisotropic rock mass. To locate the merging caverns of the Šentvid tunnel in most favourable rockudmass conditions the exploratory tunnel was constructed in the design stage and enabled 3D displacementudmeasurements ahead of the top heading face of the main motorway tunnel during its construction.udExtensive information about the scheme and execution of this experiment is given (no reports have beenudfound so far of any similar experiments). Monitored displacements were analyzed according to mappedudgeological structure. Further on, the observed phenomena and the influence of the exploratory tunnel andudits position on the displacements were studied with 3D numerical calculations.
展开▼
