Sediments in collapse dolines on the Kras plateau, Slovenia

The article presents a detailed geomorphological analysis of collapse dolines on the Kras plateau in Slovenia with particular stress on the morphogenetic development of their floors covered with loamy sediment. Granulometric and mineral composition of the loamy sediment were analysed and the depths of sediment fills were established with electrical resistivity imaging (ERI). Collapse doline development and transformation processes are discussed, and various formation mechanisms of flat loamy doline floors are considered in the article. The results of the study revealed that loamy fills may represent sedimentation of suspended material from floodwaters that inundated the lower parts of the collapse dolines, or could have originated in now-demolished cave passages on the slopes that were filled with finer material. Some sediment has been accumulated as an aeolian deposit

Active and relict alluvial fans on contact karst of the Vrhpoljska brda hills, Slovenia

Several types of contact karst are found within the Slovenian karst, but the most common is the ponor type, which usually develops at boundaries between flysch and limestone. One of these types is in the area of Vrhpoljska brda. In this contact karst area two types of alluvial fans appear on carbonate bedrock. Members of the first type are ordinary alluvial fans with active alluvial processes where flysch derived sediment covered limestone surface in a distinct fan shape. The other type, described as relict alluvial fans, is fan-shaped features preserved in the carbonate bedrock. These essentially bedrock landforms developed as a result of the gradual removal of pre-existing alluvial fan cover and the concurrent but non-uniform chemical denudation of the underlying carbonate bedrock. Geomorphologic and morphometric description of alluvial fans and relict alluvial are provided in the article and mechanisms of relict alluvial fans formation and transformation are discussed

Investigation of Structure of Various Surface Karst Formations in Limestone and Dolomite Bedrock with Application of the Electrical Resistivity Imaging

Karst landforms are developed in different kind of rocks and in different structural settings. Authors are presenting some results of profile measurement of Electrical resistivity imaging in some dolines and collapse dolines that developed in lime­stone and dolomite in Slovenia. Selected features are examples of surface karst landforms whichcould be morphologically de­fined as typical of its kind. For electrical resistivity imaging data collection was used SuperSting R1/IP earthresistivity meter. Electrical resistivity imaging method was applied for researchof material characteristics beneathsurface of karst landforms. Materials withhigher portion of water as fractured bedrock or clay are less resistant to electrical current than unfractured bed­rock. Application of the ERI method has turned out as appro­priate for detailed investigation of surface karst landforms

Periodically inundated uvalas and collapse dolines of Upper Pivka, Slovenia

Within the area of Upper Pivka there is a number of intermittent lakes because of oscillation of water table level close to the surface i.e. shallow karst. Our survey was focused on morphogenetic interpretation of depressions hosting intermittent lakes by means of classic morphographic mapping and sediment analyses that was supported by electrical resistivity tomography. We can interpret at least two different morphogenetic types of depressions. One type are depressions which are periodically inundated uvalas positioned in-between conical hills. The second type are circular depressions within karst plain that are collapse dolines filled with extensive flood deposits up to several metres thick

Modelling of slope processes on karst

The present paper is concerned with the modelling of the karst slope processes. A simple straightforward one dimensional physical model is introduced in order to assess basic behaviour of the slope development. The model takes in account mass continuity of weathered material, the mechanical and chemical weathering of the bedrock. The paper focuses on the slope formation with respect to the ratios between different magnitudes of governing processes (mechanical and chemical weathering and mass movement). The introduced approach represents a first step in understanding slope processes and does not pose a realistic quantitative comparison with field measurements. However, the results gathered with the model show good qualitative agreement with the field observations. Three different representative cases are studied: dominant mechanical weathering case, balanced mechanical and chemical weathering case and dominant chemical weathering case

Experimental testing of load capacity of angle brackets for anchoring of solid wooden panels

Different angle brackets for anchoring solid wooden panels were tested to learn about their\ud response and basic mechanical properties on the acting load in two perpendicular directions.\ud Namely, previous tests showed two distinct cases of panel deformation. In one case the panel\ud mainly rotates around its compressed corner. In the other case the panel slips along foundation\ud and deforms into parallelogram shape. Based on this knowledge, the tests were designed to\ud simulate these two cases of deformation. The two tests were named »up-lift test« and »slip\ud test«. The tests were carried out on cross laminated and unidirectional laminated wooden\ud panels segments anchored by BMF and WÜRTH angle brackets. To obtain reliable\ud mechanical characteristics three different loading protocols were applied. Loading protocols\ud to simulate realistic loads on angle brackets were monotonous, according to standard EN\ud 26891, and cyclic or semi-cyclic according to standard prEN 12512. The tests showed that the\ud length of nails has greater influence on the results that their number. The test results show that\ud cross laminated panel has better possibility for strong fixation than unidirectional laminated\ud panel

Kraška polja v Sloveniji

Kraška polja so kotanje v krasu, ki so zelo pogoste zlasti na Dinarskem krasu. Kljub številnim skupnim značilnostim se pojavljajo v zelo različnih kraških okoljih in delujejo na različne načine. V raziskavi je predstavljena nova tipizacija kraških polj, ki poenostavlja dosedanje tipizacije. Polja opredeljuje glede na geomorfološko okolje, v katerem se pojavljajo, kot ojezerjena, prelivna, pritočna in predledeniška. V raziskavi smo na osnovi nove tipizacije opredelili vseh 35 kraških polj v Sloveniji

Ilovnate zapolnitve v udornicah v zaledju izvirov Ljubljanice

V besedilu so obravnavani procesi oblikovanja in preoblikovanja udornic v neposrednem zaledju izvirov Ljubljanice pri Vrhniki. Podrobneje so proučene značilnosti in mehanizmi oblikovanja ilovnatih uravnav v dneh udornic. Uravnave v dneh udornic so posledica sedimentacije ilovnatega materiala iz poplavne vode, ki je ob višjih nivojih piezometra zapolnjevala dna udornic. Globina ilovnatih zapolnitev, ki večinoma presega globino 30 metrov, je bila ugotovljena z uporabo metode električne upornosti tal

A new view of the spin echo diffusive diffraction on porous structures

Analysis with the characteristic functional of stochastic motion is used for the gradient spin echo measurement of restricted motion to clarify details of the diffraction-like effect in a porous structure. It gives the diffusive diffraction as an interference of spin phase shifts due to the back-flow of spins bouncing at the boundaries, when mean displacement of scattered spins is equal to the spin phase grating prepared by applied magnetic field gradients. The diffraction patterns convey information about morphology of the surrounding media at times long enough that opposite boundaries are restricting displacements. The method explains the dependence of diffraction on the time and width of gradient pulses, as observed at the experiments and the simulations. It also enlightens the analysis of transport properties by the spin echo, particularly in systems, where the motion is restricted by structure or configuration