20.500.12556/RUL-190981 Nelinearna numerična analiza vpliva izkopa in varovanja gradbene jame na sosednje objekte na Ljubljanskem barju Nonlinear numerical analysis of excavation and excavation-support effects on adjacent structures in the Ljubljana Marshland Naloga obravnava nelinearno numerično analizo izkopa in varovanja gradbene jame na severnem robu Ljubljanskega barja. Približno 9,2 m globok izkop sega v visoko stisljive barjanske sedimente in bo varovan z armiranobetonsko diafragmo debeline 60 cm in tremi nivoji jeklenih razpor. V neposredni bližini jame stojijo štirje objekti. Odziv takih tal je izrazito nelinearen, konstitutivni modeli pa ga opisujejo različno. Analizirali smo, kako izbira konstitutivnega modela za sloj barjanskih sedimentov vpliva na pomike varovalne konstrukcije in sosednjih objektov ter na notranje statične količine v diafragmi. Analize smo izvedli s programom PLAXIS 2D v ravninskem deformacijskem stanju, v dveh prečnih prerezih z različno zasnovo razpiranja. Za vsak prerez smo pripravili štiri različice izračunov, ki se razlikujejo le po konstitutivnem modelu barjanskih sedimentov: Mohr-Coulomb, Soft Soil, Hardening Soil in Hardening Soil with Small-Strain Stiffness. Izbira modela ne spremeni oblike deformacijskega polja in ovojnic notranjih sil, spremeni pa njihovo velikost. Največje vrednosti dobimo z modeloma Hardening Soil in Hardening Soil with Small-Strain Stiffness, ki se pri notranjih statičnih količinah razlikujeta do 12 %, pri pomikih pa do 25 %. Vrednosti, izračunane z modeloma Soft Soil in Mohr-Coulomb, so sistematično manjše: dvižki dna gradbene jame za 5 do 32 %, pomiki diafragme za 15 do 37 %, posedki sosednjih objektov za 16 do 67 %, notranje statične količine v diafragmi in razporah pa za 14 do 34 %. Enostavnejša modela sta zato z vidika projektiranja manj konservativna. Primerjane so karakteristične vrednosti pomikov in notranjih sil, brez upoštevanja delnih varnostnih faktorjev. Ker meritve pomikov s terena niso na voljo, so izračunane vrednosti zgolj primerjalne napovedi. This thesis presents a nonlinear numerical analysis of the excavation and support of a construction pit on the northern edge of the Ljubljana Marshland. The approximately 9.2 m deep excavation reaches into highly compressible marsh sediments and will be supported by a 60 cm thick reinforced concrete diaphragm wall and three levels of steel struts. Four buildings stand in the immediate vicinity of the pit. The response of such ground is markedly nonlinear and constitutive models describe it differently. We analysed how the choice of the constitutive model for the marsh sediment layer affects the displacements of the support structure and of the adjacent buildings, and the internal forces in the diaphragm wall. The analyses were carried out in PLAXIS 2D under plane strain conditions, in two cross sections with different strutting arrangements. For each cross section we prepared four calculation variants, differing only in the constitutive model of the marsh sediments: Mohr-Coulomb, Soft Soil, Hardening Soil and Hardening Soil with Small-Strain Stiffness. The choice of model does not change the shape of the displacement field or of the internal force envelopes, but it does change their magnitude. The largest values are obtained with the Hardening Soil and Hardening Soil with Small-Strain Stiffness models, which differ by up to 12 % in internal forces and by up to 25 % in displacements. The values computed with the Soft Soil and Mohr-Coulomb models are systematically smaller: the heave of the excavation base by 5 to 32 %, the displacements of the diaphragm wall by 15 to 37 %, the settlements of the adjacent buildings by 16 to 67 %, and the internal forces in the diaphragm wall and struts by 14 to 34 %. Characteristic values of displacements and internal forces are compared, without partial safety factors. Since no field measurements of displacements are available, the computed values are only comparative predictions. Gradbena jama konstitutivni modeli tal barjanski sedimenti metoda končnih elementov PLAXIS 2D Excavation pit constitutive soil models marsh sediments finite element method PLAXIS 2D true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-11-09 15:57:31 2026-11-09 15:57:37 2026-11-10 04:10:04 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 187955 24408.pdf 24408.pdf 1 8985EC32AD750A8C74D6C18287F06FC1 1a6a27bf822c2e8beef49eebf0016741f4ff7673cba47082213ba1326aa4c7b8 cfc37ece-dc4d-11f1-aea2-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=252820 Fakulteta za gradbeništvo in geodezijo 0 0 0