Back analysis of time-dependet displacement at the Trojane tunnel constructionJakob Likar
, 2004, izvirni znanstveni članek
Opis: The 2,900-metre double tube tunnel of Trojane forms part of the highway section between Celje and Ljubljana and part of the highway road system connecting Lendava and Koper with adjacent roads. The construction of this section, which is of special importance for the Republic Slovenia, has been going on for almost ten years.
The highway near Trojane where the tunnel is located, lies on a hilly terrain composed of Permian-carboniferous rocks, which are tectonically badly damaged in some places and marked with broad fault zones, containing tectonically remoulded soil of low strength in terms of deformability properties. Even though the amount of waters coming from the hills during the excavation of the tunnel was relatively small, this water, in combination with extremely damaged weak rock caused the increase of deformations at the construction site.
Geological and geotechnical surveying with geometric monitoring and the analyses of stress and deformation changes in the surrounding rocks and support elements were critical in assessing the actual weak-rock conditions during the course of construction. Since the analyses of deformation processes, which had been modelled with PLAXIS 3D TUNNEL PROGRAM, showed great impact on permanent stability of the tunnel, special care was paid to rheological changes in the surrounding rocks and combined in-built support elements.
3D back analyses with SOFT-SOIL-CREEP (SSC) constitutive model, which takes into account rheological phenomena, were carried out. The calculations of primary and secondary stresses and deformations were made for two characteristic areas and determined on the basis of realistic geological mapping during tunnel construction. The first area represented typical rocks of the Trojane tunnel, i.e. shales and siltstone, while the second one was a tectonic zone where geological and geotechnical conditions during excavation were less favourable. The results of back analyses used provided an acceptable possibility for estimating the stress-strain variation during construction as well as an appropriate basis for analysing vertical displacements at the tunnel roof. The calculation results show good correlation with field measurements.
Ključne besede: tunnels, construction, permain-carboniferous rocks, geological-geotechnical conditions, tunnel support, Trojane tunnel, finite element method, costitutive models, back analyses, field mesurement, time dependent analysis
Objavljeno: 15.05.2018; Ogledov: 34; Prenosov: 1
Celotno besedilo (868,88 KB)
Radon anomalies in soil gas caused by seismic activityBoris Zmazek
, Mladen Živčić
, Ljupčo Todorovski
, Sašo Džeroski
, Janja Vaupotič
, Ivan Kobal
, 2004, izvirni znanstveni članek
Opis: At the Orlica fault in the Krško basin, combined barasol detectors were buried in six boreholes, two along the fault itself and four on either side of it, to measure and record radon activity, temperature and pressure in soil gas every 60 minutes for four years. Data collected have been analysed in a manner aimed at distinguishing radon anomalies resulting from environmental parameters (air and soil temperature, barometric pressure, rainfall) from those caused solely by seismic events. The following approaches have been used to identify anomalies: (i) ± 2σ deviation of radon concentration from the seasonal average, (ii) correlation between time gradients of radon concentration and barometric pressure, and (iii) prediction with regression trees within a machine learning program. In this paper results obtained with regression trees are presented. A model has been built in which the program was taught to predict radon concentration from the data collected during the seismically inactive periods when radon is presumably influenced only by environmental parameters. A correlation coefficient of 0.83 between measured and predicted values was obtained. Then, the whole data time series was included and a significantly lowered correlation was observed during the seismically active periods. This reduced correlation is thus an indicator of seismic effect.
Ključne besede: radon in soil gas, environmental parameters, earthquakes, correlation, regression trees, forecasting
Objavljeno: 15.05.2018; Ogledov: 30; Prenosov: 0
Celotno besedilo (271,01 KB)
Undrained shear strength of saturated cohesive soils depending on consolidation pressure and mineralogical propertiesBojana Dolinar
, 2004, izvirni znanstveni članek
Opis: The relationship between the water content and the undrained shear strength of finely grained soils can be described with a nonlinear function in which the type of soils is determined by two parameters. These parameters depend primarily on the size of clay minerals, their quantity in soil composition and the interlayer water quantity in expanding clay minerals. This article asserts that there exists also the exactly defined relationship also between the water content and consolidation pressure. In the function describing this relationship, the type of soil is determined by two parameters. They can be expressed depending on the same mineralogical properties of soils as the values of parameters in the function showing the relationship between the water content and the undrained shear strength. These findings allow us to express the ratio between undrained shear strength and consolidation pressure depending on mineralogical properties of soils.
Ključne besede: soil mechanics, properties of soils, clays, specific surface, undrained shear strenght, compressibility
Objavljeno: 15.05.2018; Ogledov: 29; Prenosov: 0
Celotno besedilo (103,26 KB)
Matematika 1Tina Sovič
, Simon Špacapan
, 2018, univerzitetni, visokošolski ali višješolski učbenik z recenzijo
Opis: Skripta Matematika 1 zajema osnovna znanja matematike, ki ga potrebujejo študentje visokošolskih programov Fakultete za gradbeništvo,prometno inženirstvo in arhitekturo. V prvem delu skripte so predstavljena poglavja iz področja analize, v drugem delu pa poglavja iz področja algebre. Natančneje, začnemo z zaporedji, kjer opredelimo osnovne pojme, kot so omejenost, monotonost in konvergenca zaporedja. Sledi poglavje, ki na kratko predstavi kompleksna števila in operacije med njimi. Nato so opisane osnovne elementarne funkcije ter predstavljena pojma limita funkcije in zveznost. Definiramo odvod funkcije in pokažemo njegovo uporabo pri določanju lokalnih ekstremov. Odvodu sledi definicija integrala skupaj z njegovo uporabo. Prvi del skripte zaključuje poglavje o funkcijah dveh spremenljivk. V drugem delu predstavimo geometrijske vektorje in operacije med njimi. V nadaljevanju obravnavamo premice in ravnine v prostoru. Skripto zaključimo s poglavjem o matrikah, kjer opišemo osnovne matrične operacije, sisteme enačb in matriko linearne preslikave.
Ključne besede: zaporedja, funkcije, odvod, integral, vektorji, sistemi enačb, matrike
Objavljeno: 17.04.2018; Ogledov: 123; Prenosov: 12
Celotno besedilo (2,44 MB)
Collective sensing of ß-cells generates the metabolic codeDean Korošak
, Marjan Rupnik
, 2018, izvirni znanstveni članek
Ključne besede: collective sensing, pancreatic islets, spin glass models, metabolic code, Ca2+ imaging, Ca2+ signaling, correlations, intercellular communication
Objavljeno: 25.01.2018; Ogledov: 90; Prenosov: 5
Celotno besedilo (2,25 MB)
Survey of accomplishments in BIM implementation in Croatia, the Czech Republic, Germany, and SloveniaMario Galić
, Vaclav Venkrbec
, Franziska Chmelik
, Immo Feine
, Zoran Pučko
, Uroš Klanšek
, 2017, izvirni znanstveni članek
Opis: Building information modelling (BIM) may currently be considered the fastest developing concept in the field of construction management, aiming to become a global standard. Although the roots of the concept date back to the mid-1970s, some original expectations are still missing from its implementation. There has been a time gap between its theoretical and practical implementations. While the simultaneous development of information technologies is one reason for the implementation delay, other reasons remain unclear. This paper analyzes the gaps between theoretical and practical BIM application, as well as the legislation regarding BIM implementation in four countries (in alphabetical order: Croatia, the Czech Republic, Germany, and Slovenia). The paper additionally presents a survey of current practical BIM applications as well as general and theoretical feedback from construction projects that implemented BIM.
Ključne besede: construction industry, implementation, project management, survey
Objavljeno: 12.01.2018; Ogledov: 130; Prenosov: 5
Celotno besedilo (694,12 KB)