GraevinarstvoPredavanje 1.

1.

to se geoloke grae tie, Fruka gora je veoma raznolika i sastoji se od stena raznovrsnog sastava, naina postanka i razliite starosti. Paleozojske tvorevine ine jezgro Fruke gore, a obuhvataju razliite stene od kojih su najrasprostranjeniji filiti (phyllites) i liskunoviti krenjaki kriljci (micaceous limestone schists). Inae, ove tvorevine su najee visoko metamorfisane, a njihova rasprostranjenost u odnosu na ostale predstavnike dosta je velika.

Mezozojske tvorevine na Frukoj gori prisutne su u manjoj meri u odnosu na paleozojske, i javljaju se u vidu uskih zona male debljine. Pripadaju trijaskim crvenim i sivim pearima (sandstones) i liskunavitim kriljcima, konglomeratima, brecama (breccias) i drugim stenama.

Tercijerne tvorevine imaju znatnu rasprostranjenost i uestvuju u grai perifernih delova Fruke gore. Ove tvorevine okruuju bilo (ridge) Fruke gore i predstavljene su slojevima sa ugljem, lajtovakim krenjacima (Lajtovac), laporcima (marlstones) i pearima i dr.

Kvartarne tvorevine prisutne su u vidu debelih naslaga lesa (loess) koje pokrivaju nie delove Fruske gore. Geoloka i paleontoloka istraivanja koja na ovoj planini traju ve skoro dva veka, ukazuju da je ona riznica zapisa (mnotvo biljnih i ivotinjskih fosila) o istoriji prirode. Na osnovu njih rekonstruisan je tok prirodnih promena na Frukoj gori od pre oko 200 miliona godina pa sve do dananjih dana.

2. Adaptacijom Osnovne geoloke karte 1:100.000, list Gornji Milanovac (Filipovi i dr, 1971), sve geoloke formacije svrstane su u est grupa po vrstama stena. Generalizacija je doprinela boljoj jasnoi i lakoj upotrebi karte, a litoloki pregled je od sutinskog znaaja za aplikativnu vrednost karte. Na karti su predstavljene sledee grupe stena: 1) aluvijalno-deluvijalni i ostali nevezani sedimenti, 2) konglomerati, bree, tufovi (tuffs) i peari, 3) fli (flysch), 4) kompaktne magmatske stene, 5) krenjaci i laporci, 6) metamorfne stene. Nevezani sedimenti najzastupljeniji su u dolini reke Ljig i severno od reke Kaer, u vidu ljunkova, peskova i glina. U grupi konglomerata, brea, tufova i peara velik je broj razliitih formacija, koje nisu posebno teritorijalno grupisane, ve prisutne na mnogim manjim lokacijama, naroito u dolini Kaera. Fli je stenski kompleks koji je u velikoj meri zastupljen na teritoriji optine Ljig. Tzv. ljiki fli prua se zapadno od Boljkovakog raseda, u irokom pojasu severno i istono od vulkanita (vulcanite) Slavkovice, dok je istono od Boljkovakog raseda najrasprostranjeniji fli preteno pearskog sastava. Kompaktne magmatske stene javljaju se zapadno od Slavkovice (kvarc-latiti quartz-latites, daciti - dacites ), te u ataru sela ivkovci (granit-monacit granite-monazite). Krenjaci i laporci su preteno prisutni u krajnjem jugozapadnom delu optine, na severnim padinama Suvobora, a javljaju se i sporadino, u vidu manjih izdanaka i soiva (lenses), i u ataru sela Moravci. Od metamorfnih stena, u atarima sela Ba i Palenica ima serpentinita (serpentinites), koji su deo dijabaz-ronake (diabase - hornstone) formacije.

Osim toga, razliiti kriljci (muskovit-biotitski muscovite-biotite, sericitski - sericite, itd), te krupnozrni gnajsevi (gneiss), javljaju se na severoistoku optine, na prostoru ivkovaca, Kalanjevaca i utaca, i predstavljaju kontaktno promenjene stene bukuljskog granitoida.

3. GEOLOGICAL AND SEISMIC PROPERTIES

The geological structure of Mt. Rajac is mainly formed of flysch rocks and other Upper Cretaceous sediments. The northern side of Mt. Rajac is delineated by steep limestone escarpments. At the top of Ba village (above Ljig springs), steep slopes stretch toward the east: Mt. Rovanica, Kojia kom (the Kojic Fortress), Provalija and Beli potok (White Creek).

Eruptive rocks are noticeable with overlying schists and sandstones. The southern side of Mt. Rajac is formed of serpentines of Jurassic age. The very peak of Mt. Rajac is a conical elevation formed of limestone. The stretch from Mt. Suvobor to Mt. Rudnik is formed of the wide plates of limestone and marly limestone (the Upper Cretaceous). While the limestone plates in the west are up to 150 m thick, those underlying a wider area of the inhabited part of Mt. Rajac are about 50 m thick.

Karstification is a frequent process here. Lithological composition, purity and crystallinity of karst vary, but its layers are much disturbed, faulted and jointed.

According to the current Seismological Map of Serbia, the area of Mt. Rajac is classified as the region of a seismic intensity of the 7th degree (Mercalli scale).

4. LOCATION AND DEPTH OF BORINGS

This section is to be used as a guide in planning the boring program. It is not the intent that the location, boring interval, and depth specified herein be rigidly adhered to. The consultant shall make use of available soils and geologic maps, water well records, reports, publications, aerial photographs, and other reference material which are available to prepare a preliminary boring program. Borings shall then be selectively located during a field check attended by the consultant geotechnical engineer and by the foundation analysis engineer or his appointed representative.

The actual location, spacing, and depth of borings shall be dictated by the topography, geologic conditions, visible soil conditions, and design considerations, and in accordance with the practices set forth herein.

Depth of Exploration

Borings should extend through any unsuitable or questionable foundation materials and sufficiently deep into stable soils that the potential for settlement from compression of that layer or that the deeper underlying soils is determined. If deep excavations are required for building the structure, the explorations should be carried to at least 1.5 times the depth of the excavation in order to locate and determine groundwater levels in any aquifers that may exist below the level of excavation. This is necessary to design a dewatering system that may be required in such deep excavations and to avoid heave or disturbance to the bottom of the excavations. Spacing and Number of Borings

Often borings are made in several stages. In the first stage, relatively few borings are made. Based upon these findings, additional borings may be made between the initial borings to define soil conditions in greater detail. The selection of sample type and frequency is determined by soil conditions and requirements of the structure. Where soil conditions are favorable, especially for small structures, all borings are often completed in the first phase of the investigation. If soil conditions are well known with fairly thick individual layers of consistent physical properties, relatively widely spaced borings may be sufficient. If, however, soil conditions vary appreciably from place to place, more closely spaced borings will be required. The number and spacing must be determined by engineering judgment as the work progresses. There should be a sufficient number to determine the stratification and interrelation of the soils to the extent economically feasible. The exploration should be conducted considering the requirements of the structure. All soil data necessary for the selection of the foundation and its design must be obtained.