The SPE has split the former "Management & Information" technical discipline into two new technical discplines:
- Data Science & Engineering Analytics
The SPE has split the former "Management & Information" technical discipline into two new technical discplines:
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The PDF file of this paper is in Bosnian. _ Abstract The first section of the Smokovac-Mateševo highway in Montenegro was built, with a length of 41 km. Half of the route was formed within flysch sediments, along which numerous terrain instabilities were registered during construction. The most significant landslide was registered in the area of the Uvač 4 bridge, where 100 000 m3 of material was moved by the formation of a sliding plane at a depth of 20 m. Initially, deformations appeared on the ground with the formation of a 27 m-long scar, and later the movement of the L2O1 support of the Uvač 4 bridge by more than 40 cm was registered. Extensive rehabilitation works were carried out by forming deep foundation supporting structures and securing the slope with cable anchors. The paper analyzed the values of the physical-mechanical parameters of flysch sediments given in the main project, as well as the shear parameters of flysch sediments obtained by reverse stability analysis. In the end, an assessment of the cause of terrain instability is given, as well as a description of the performed rehabilitation works.
Qiu, Tianqi (Tsinghua University) | Yang, Jun (Tsinghua University / National Engineering Laboratory for Green & Safe Construction Technology in Urban Rail Transit) | Wu, Zhixuan (Tsinghua University) | Shen, Zhaopu (China Road and Bridge Corporation) | Liang, Yufan (China Road and Bridge Corporation)
Abstract Aiming at fully considering the influence of bolt length on stability of flysch layered slope, safety factors and failure modes of layered slope with different dip angles of bedding plane and equal-length bolts were analyzed by finite element limit analysis code Optum G2. Then bolt length distribution was optimized to obtain the bolt combination which has minimum total bolt length without reducing safety factor. The results show that as the bolt length increases from 1m to 28m, the safety factor of layered slope keeps constant first and then increases and finally keeps constant or increases first and then keeps constant. As the dip angle increases from 0° to 90°, the effective bolt length of layered slope increases first and then decreases and then increases. The maximum effective bolt length is 26m and the minimum one is 12m corresponding to slopes with 20° and 40° dip angles respectively. As the dip angle increases from 0° to 90°, the limit increase rate of safety factor increases first and then decreases and then increases, which ranges from 38% to 97%. As the bolt length increases from 1m to 28m, the movement of failure surface could divide into three stages: First, failure surface is same to that of slope without bolt. Second, failure surface moves deeper as bolt length increases. Third, failure surface changes from a deep one to a shallow one suddenly and then keeps unchanged. The critical bolt length of last two stages is the effective bolt length. Through the optimization of bolt length distribution, bolt materials could be saved with saving rates ranging up to 36%. The optimization result is closely related to the failure mode of slope without bolt. That means, the deeper the failure surface of the slope without bolt is, the longer optimized bolt needed to cross the failure surface is. 1. Introduction Flysch is a kind of marine sedimentary structure generating from the process of sedimentation, which is very common in Europe and south china. Flysch rock is a typical layered rock, which is generally composed of interlaced sandstone, shale and mudstone. Flysch rock has obvious layered structure and anisotropic characteristic and the soft rock in it such as mudstone is easy to be weathered by water and air (Jaeger, J. C. et al., 1960; Marinos, P. et al., 2001; Zhao, Z. et al., 2016; Wu, X. et al., 2017; Qiu, T. Q. et al., 2018). The layer structure and characteristic of easy-weathering make flysch layered slope have different stability and failure mechanism comparing with isotropic slope. Along the South-North Highway constructed by CRBC in Montenegro, there are 20 kilometers line crossing flysch area. The photos of flysch layered slopes in Montenegro are shown in Fig. 1.
ABSTRACT: The protection of karst wells against the sea water intrusion has been often avoided due to the fear for such actions to be undertaken in the karst regions. However, in favorable hydrogeological conditions many wells of that sort have been reliably and economically protected in the artificial way against the salting sea water influence. The karst well "Morinj" is examined in this study, which geological, tectonic and hydrogeological conditions enable its protection against the salting sea influence to be reached by injection curtain. The sea well is located in the Kotor Bay (Bokokotorski zaliv), on the Montenegrin coast, along the southeast shore of the Adriatic sea. (Fig. 1) The salted well has capacity about 600 lit/sc, and is situated in the area that lacks the drinking water very much. BASIC GEOLOGICAL AND HYDROGEOLOGICAL FEATURES The river basin of the Morinje water-well is located in the karstified and high cretaceous limestones. They are stretching in the west-northwest direction and go all the way up to the edge of the Morinj Bay, not far from the seacoast. From the north side this good water- permeable area (K,) is limited with weakly water-permeable limestones with periodical layers of flint-stones (K). From the south side this water-permeable area is limited by continuos, compressed, and weakly waterpermeable limestones with flint-stones. Behind them stretches a concordant area of non-permeable silificonized limestones (K¹). Accordingly, alongside the considered water-passing karstified area (K,) is limited by both blocks of weakly water-permeable, that is, water-nonpermeable rocks. The limestones are extended in zones from west to east, declining towards north. It was the shelly structure that caused an abnormal super position of layers where the wooden sediments extending along the reverse longitudinal clefts cover the eocenic flisch.
Summary The paper in short describes the terrain composition, classification of the discontinuity in the rock mass on the basis of fissures stage, calculation of rock mass stability with establishing of real important facts and technical measures for sanation of the labile parts of the rock massive in the cut and on slope on some parts of the railway Beograd-Bar. On the railway from the km 85+970 – 86+858 the terrain is represented with trias limestone in thicker layers. The general direction of slope inclination is under an angle of 23° towards the massive and 15° towards the railway. The railway from the km 47+635 – 47+719 the part from Trebaljevo - Kolašin with the nearer surroundings is represented by porphyrites, which are in its surface part mechanically very damaged. The securing of the railway was done by construction of the protection walls made of old railway tracks, rustic walls made of broken stone, rock mass anchoring, and by construction of the supporting walls and clearing the labile parts of the rock mass.
Summary Most engineering-geological, i. e. geotechnical classifications proposed to date are based on the properties of samples, whereas classifications of rock masses (lithological bodies, lithological complexes, terrains), especially those that take into account their mechanical behavior, are less frequent. A terrain is exceptionally built up of one lithological body, i. e. of a sufficiently well defined rock mass of megageological size which in its natural environment represents a genetic and physical unit. It is most frequently bu ilt up of a lithological complex - an association of several lithological bodies whose mechanical behavior in the zone of influence of the structure is that of an integral whole. The relation between the sample - rock mass - terrain may be compared to the relation existing between the materials of construction - framework - structure. For the same reasons why the behavior of a framework or structure differs from that of the material of which it is made, so does the behavior of rock samples differ from the behavior of the rock mass and/or terrain (which is in fact a natural structure). We are, therefore, of the opinion that many practical and theoretical problems could be far more satisfactorily solved if the approach based on a universal medium was replaced by that based on a «natural structure» whose component parts are rock masses i. e. lithological bodies. Advantages of this approach are illustrated by a problem of decreased stability of natural and man-made slopes In a limestone-Flysch complex. Resume La plupart des classifications existentes ingenieurs-geologiques, c'est-à-dire des classifications geotechniques sont basees sur les proprietes des echantillons. Les essais de classification des massifs rocheux - par exemple des corps Iythologiques, des complexes Iythologiques, du terrain, sont assez rares, surtout s'il est question de leur comportement mecanique. Le terrain est rarement forme d'un corps lythologique - d'un massif rocheux à proportion megascopique, assez nettement limitee, qui represente dans l'ensemble naturel une unite genetique et physique. Le terrain est, dans la plupart des cas, forme d'un complexe lythologique d'une association d'un assez grand nombre de corps lythologiques, dont le comportement mecanique se manifeste integrement dans la zone influencee par l'objet. Le rapport entre l'echantillon, le massif rocheux et Ie terrain peut être compare avec celui entre le materiel, la construction et la structure. Comme le comportement d'une construction, c'est-à-dire d'une structure diffère essentiellement du comportement du materiel dont elle est construite, de même le comportement des echantillons diffère de celui du massif rocheux, c'est-à-dire du terrain - la structure naturelle. Nous semmes d'avis que la solution de beaucoup de problèmes pratiques et d'etudes theoriques à venir sera it plus favorable si, au lieu d'un milieu semi-infini universel, l'on adoptait la «construction naturelle» ou «structure naturelle », dont les elements sont les massifs rocheux, c'est-à-dire les corps lythologiques. Zusammenfassung Die meisten bestehenden ingenieurgeologischen, bzw. geotechnischen Klassifikationen sind auf Gesteinseigenschaften aufgebaut. Viel seltener sind die Versuche, grössere Gesteinsmassen - z. B. lithologische Körper, lithologische Komplexe oder Terrains - unter besonderer Beruecksichtigung ihres mechanischen Verhaltens zu klassifizieren. Das Terrain baut nur ausnahmsweise einen lithologischen Körper aus - d. h. eine genuegend deutlich begrenzte Gesteinsmasse megaskopischer Ausmasse, die im natuerlichen Gefuege ein genetisches und physikalisches Ganzes darstellt. In den meisten Fallen jedoch baut das Terrain einen lithologischen Komplex aus - eine Assoziation einer grösseren Zahl von lithologischen Körpern, deren mechanisches Verhalten in der Einflusszone des Baus einheitlich zurn Ausdruck kommt. Das Verhaltnis zwischen Gesteine - Gesteinsmasse - Terrain kann mit dem Verhaltnis zwischen Material- Konstruktion. - Bau verglichen werden. In gleicher Weise, wre das Verhalten einer Konstruktion, d. h. eines Baus, sich wesentlich vom Verhalten des Materials, aus dem es erbaut wurde, unterscheidet, so unterscheidet sich auch das Verhalten der Proben - der Gesteine - von dem Verhalten der Gesteinsmasse, bzw. des Terrains-des Naturbaus. Wir sind daher der Meinung, dass, es fuer die lösung zahlreicher praktischer sowie theoretischer Probleme guenstiger ware, wenn anstatt universaler Halbraum oder Medium etwa «Naturkonstruktion», «Naturbau» oder Felsbauwerk angewandt wuerde dessen Elemente Gesteinsmassen bzw. Most engineering-geological, i. e. geotechnical classifications suggested to date are based on the properties of samples. Attempts to classify large rock masses, i. e. lithological bodies or lithological complexes especially in view of their mechanical behavior are considerably rarer. This imposes the need for a better knowledge and classification of the properties of a considerably larger area, i. e. terrain in general. As is known, from the geotechnical standpoint terrain is the surface part of the lithosphere within the zone of Influence of a given artificial structure. Exceptionally, a terrain is built up of one lithological body - i. e. of a sufficiently well-defined rock mass which in its natural environment represents a genetic and physical unit (e. g. massives of plutonic and eruptive rocks, limestone reefs, and other large rock masses, banks, beds, or lenses of sedimentary rocks).