Geotechnical soil modeling based on the parameters obtained by seizmic dilatometer

[D. Berisavljević]

XV, 208 lista

Rudarsko inženjerstvo-Eksploatacija
vrstih mineralnih sirovina i mehanika stena / Mining engineering-Exploitation of solid mineral resources and rock mechanics

U disertaciji je prikazana analiza i interpretacija rezultata koji se dobijaju kada se tlo ispita mehani
kim (DMT) i seizmi
kim (SDMT) dilatometrom. Analizirani su pojedini
inioci koji mogu da uti
u na izmerene pritiske p0 (A), p1 (B) i p2 (C) koji su osnovni podatak koji se dobija iz opita. Interpretacija je vršena u smislu geotehni
kih parametara, pre svega
vrstoe i deformabilnosti proverom primenljivosti empirijskih zavisnosti na naše lokalne uslove i praksu. Poreenjem rezultata opita sa laboratorijskim opitima i merenjima na izgraenim objektima izvedene su nove ili potvrene postojee korelacije za: - parametre istorije optereenja (OCR, pc i k0) u finozrnom tlu, - parametre
vrstoe (j’ i su) i - parametre deformabilnosti (Eoed). Prikazane su meusobne zavisnosti izmeu otpora na prodor konusa (qc) i otpora na prodor se
iva (qD) u grubozrnom tlu. Pokazano je da se na osnovu inicijalnog modula smicanja (G0) može identifikovati tlo sa izraženom mikrostrukturom. Razlog je to što se G0 odreuje u domenu jako malih smi
uih deformacija pri kojima struktura tla ostaje neporemeena. Sa druge strane utiskivanje se
iva izaziva velike smi
ue deformacije okolnog tla, pa su svi izmereni parametri odreeni u tlu
ija je struktura delimi
no poremeena. Pokazano je da u tvrdim OC glinama iznad nivoa podzemne vode MDMT zanatno precenjuje veli
inu edometarskog modula (Eoed). U takvoj situaciji Eoed približno odgovara dilatometarskom modulu (ED). Komparacijom izmerenih i ra
unskih sleganja, za dva kapitalna objekta fundirana u dunavskom aluvionu, utvreno je da je procena sleganja iz DMT opita pouzdana. Poreenjem izmerenih sa ra
unskim vertikalnih deformacijah tla ispod silosa na obali Dunava u Beogradu izdvojen je sloj kod koga DMT opit ne daje pouzdan rezulatat i ne može da se interpretira zbog uslova dreniranja koji vladaju prilikom izvoenja opita. Od posebnog je zna
aja rezultati

 SDMT opita u kolapsibilnom lesu. Pokazano je da se na osnovu prelaznih parametara ID i KD mogu izdvojiti zone kolapsibilnog lesa. Dat je postupak prora
una sleganja primenom rezultata DMT opita za prirodno stanje vlažnosti i nakon provlažavanja lesa.

Dissertation presents analysis and interpretation of the results obtained when the soil is tested by mechanical (DMT) and seismic (SDMT) dilatometer. Factors which influence measured pressures p0 (A), p1 (B) and p2 (C) have been analysed. Interpretation is made in the light of geotechnical parameters, primarily strength and stiffness, by considering the applicability of empirical correlations on our local conditions and practice. Comparing the test results with laboratory tests and with structure performance new correlations are derived and/or existing correlations are confirmed for: - stress history parameters (OCR, pc and k0) in fine-grained soils, - strength parameters (j’ i su) and - stiffness parameters (Eoed). Interrelationships between cone resistance (qc) and blade resistance (qD) in coarsegrained soils are presented. It is shown that initial shear modulus (G0) can be utilized for determination of microstructure in soil. The reason for that lies in the fact that G0 is determined in the low shear strain region in which microstructure remains undisturbed. On the other hand blade penetration cause large shear strains in surrounding soil, so that all measured parameters are obtained in the soil with partially destroyed structure. It is shown that in stiff OC clays MDMT is significantly higher compared to oedometer modulus (Eoed). In that situation Eoed closely match dilatometer modulus (ED). Comparisson of measured with calculated settlements for two major objects constructed in Danube’s alluvion indicates that settlement prediction based on DMT is reliable. By comparing measured with calculated vertical strains in foundation soil below the Silo, at the Danube’s bank in Belgrade, layer in which DMT test results are unreliable due to occurrence of partial drainage is allocated. Of particular importance are SDMT test results in collapsible loess. It is shown that intermediate parameters ID and KD can be
used to separate zones of collapsible loess. A method for calculating settlements in loess with natural moisture content and after saturation is proposed.

dilatometar, brzina smi
uih talasa,
vrstoa i deformabilnost, sleganje, les, mikrostruktura

dilatometer, shear wave velocity, strength and stiffness, settlement, loess, microstructure

624.131.1:551.2(043.3)

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