When analysing the measured displacements at the Trojane tunnel (Slovenia), excavated in soft foliated rock mass, some interesting deformation patterns were observed, especially large surface ...settlements that appeared despite quick ring closure, stiff lining and consequently small tunnel lining displacement. It soon became clear that most of these phenomena are the consequences of highly anisotropic nature of the soft foliated rock mass. A vast number of numerical analyses were performed, varying dip direction and dip angle of the anisotropy planes as well as strength and stiffness parameters of the rock mass (degree of rock mass anisotropy). The share of displacements that occur ahead of the tunnel face and the extent of influential zone ahead of the tunnel face are presented as primary results. Further on, the effect of tunnelling with and against the anisotropy planes in the same material is presented. The effect of overburden above the tunnel and the influence of the orientation of anisotropy plane on the surface settlements were investigated. To verify the obtained numerical results, comparisons to the measurements inside and above the Trojane tunnel were made.
•Share of displacements occuring ahead and behind face for different dips and dip directions is given.•This enables very good fit of displacement function to measured tunnel displacements.•In soft foilated rock it may be more convenient to excavate a deep tunnel with dip.•Under low overburden in the same rock the tunnel excavation shall proceed against dip.•In such rock, high surface settlements can be expected at over 100m overburden.
This paper argues that there is a requirement for standardized nomenclature and a selection methodology for a particular class of temporary support. The authors have chosen the term Umbrella Arch ...(UA) to define the method of support that acts as pre-support that is installed during the first pass of the excavation around and above the crown of the tunnel face. The UA supports the rock mass and the tunnel face predominately by transferring loading longitudinally through the interaction of the support and surrounding ground condition. There are three categories of UA. Categorization depends on the type of support element used. These elements include: (1) Spiles; (2) Forepoles; and (3) Grouted. These categories can be further divided into 11 sub-categories quantified by the amount of grout utilized in the installation. The sub-categories are justified by the employment of each sub-category within a support selection methodology for an UA; this was created by the authors based on experience and through a comprehensive literature search that included published papers as well as design reports. The collection of publications has resulted in 141 permutations of different temporary tunnel support in varying weak and difficult geological condition. The UA support selection methodology was created to aid tunnel designers in these conditions with the basic concepts for the appropriate selection process for an UA. Furthermore, the authors quantified the support selection methodology through the employment of other pre-existing design charts and empirical evidence to create a new design tool, the UA selection chart. Overall, this paper hopes to achieve the creation of an international standard with respect to UA and UA support element nomenclature and a better understanding for the selection of a particular UA sub-category.
A multianchored pile retaining wall was constructed to protect the cut made for the cut and cover section of the twin Trojane Tunnel. Deformation monitoring surveys were conducted and measurements of ...movements were carried out throughout the construction cycle of the wall and beyond. In order to determine design parameters for the soil strata embedded in a complex geological sequence, the soil-wall interaction was back analyzed using the finite element method. The technical note describes the process of selection of material parameters through careful assessment of the laboratory data and the results of the numerical back analyses. Once selected, the parameters were verified on the other cut and cover sections of the same tunnel and later used in routine design. Generally, a good agreement between predicted and observed behavior was achieved suggesting the adequate determination of the geotechnical model and the soil parameters.
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Dostopno za:
DOBA, FGGLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Der Beitrag berichtet über ein Buch der Initiative "epicenter works", die an dem Umstand, dass Gesetze, die Überwachung ermöglichen, bisher nicht auf ihre Wirksamkeit hin überprüft worden sind, ...ansetzt. Das Buch listet alle relevanten Gesetze in Österreich auf, um so die Grundlage für eine Evaluation zu schaffen.
Nuclear reaction rates are among the most important input for understanding primordial nucleosynthesis and, therefore, for a quantitative description of the early universe. An up-to-date compilation ...of direct cross-sections of super(2)H(d, p) super(3)H, super(2)H(d, n) super(3)He, super(7)Li(p, alpha ) super(4)He, and super(3)He(d, p) super(4)He reactions is given. These are among the most uncertain cross-sections used and input for big bang nucleosynthesis calculations. Their measurements through the Trojan Horse method are also reviewed and compared with direct data. The reaction rates and the corresponding recommended errors in this work were used as input for primordial nucleosynthesis calculations to evaluate their impact on the 2H, super(3,4)He, and super(7)Li primordial abundances, which are then compared with observations.
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