FUNDAREA PE LOESS A TURBINELOR DIN PARCUL EOLIAN FÂNTÂNELE – ROMÂNIA

Autor/autori: Prof. dr. ing. Romeo CIORTAN

Rezumat: Turbinele eoliene constau dintr-un turn metalic înalt de cca. 100,0 m care susţine în vârf o nacelă de 900 KN prinsă articulat, în axul căreia se află rotorul cu trei pale de cca. 50,0 m lungime fiecare. Prin studii geotehnice s-a constatat că deasupra unui teren şistos se află un strat de loess cu grosime de până la 25,0 m, care are o mare sensibilitate la umezire, producându-se tasări generale şi diferenţiate chiar sub propria greutate, care pot conduce la degradarea structurii turbinei. La baza turnului s-a prevăzut un radier de beton armat de formă octogonală cu distanţa între două laturi paralele de 16,2 m, cu volumul de 441 m3, fiind lestat cu o umplutură de pământ de 210 m3. A fost adoptată fundarea directă a radierului, consolidându-se terenul cu 105 incluziuni de beton simplu cu ø = 36 cm, având la partea superioară un strat de transfer de 55 cm din loess stabilizat. Soluţia tehnică prevăzută prezintă astfel următoarele avantaje: înlocuirea fundării indirecte a radierului, pentru care ar fi fost necesari piloţi din beton armat; consolidarea şi desensibilizarea economică a terenului loessoid; adoptarea unei tehnologii ecologice pentru realizarea incluziunilor, prin îndesarea terenului, fără extragere de material; utilizarea loessului pentru stratul de transfer, folosindu-se la maximum materialul excavat; rezistenţa şi impermeabilitatea obţinute prin stabilizare cu adaos de cca. 4% ciment; reducerea duratei de execuţie a lucrărilor cu 25%, de la 600 zile la 400 zile. Prin soluţiile adoptate au fost asigurate atât cerinţele de stabilitate şi rezistenţă a structurii turbinelor eoliene, cât şi cele ecologice, pe toată durata de funcţionare a acestora

Cuvinte cheie: energia vântului, loess, incluziune, strat de transfer

Abstract: Wind turbines consist of a metallic tower having approximatively 100,0 m height and sustaininig on top a hinged basket of 900 kN weight. In the basket’s shaft is placed the rotor having three blades each of approximatively 50,0 m length. The geotechnical study revealed that above a schist rock is located a loess layer with thickness up to 25,0 m. Because the loess is very sensitive to water, both total and differential settlements (even under its own weight) can take place, damaging the converter’s structure. At the tower’s base was provided a mat foundation having an octogonal shape, a total volume 441 m3 and the distance between two parallel sides of 16,2 m. The mat foundation was covered with a soil filling having a total volume of 210 m3. A direct foundation was adopted for the mat as the soil was reinforced with 105 concrete inclusions with a diameter of 36 cm and having at the upper part a 55 cm transfer layer of stabilised loess. The adopted technical solution has the following advantages: replacing the deep foundation of the slab for which would have been necessary reinforced concrete piles; consolidation and economical reduction of sensitivity to water for the loessoidal soil layer which had a large thickness; adopting an ecological technological solution for constructing the inclusions; this technology allows both drilling and compaction of soil without extracting material; using the loess for the transfer layer has enabled the full utilisation of the excavated material; the necessary resistance and impermeability for this loess layer was obtained by addition of aproximatively 4 % cement; reduction of the construction schedule by 25 %, from 600 to 400 days. Through the adopted solutions were ensured both the stability and resistance requirements for the converter’s structure neccesary to exploit wind energy, as well as, the ecological requirements throughout their lifetime

Keywords: wind energy, loess, inclusion, tranfer layer

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