Primerjava metod za oceno potenciala likvifakcije na podlagi terenskih raziskav tal

Oblak, Aleš (author), Logar, Janko (mentor)

V magistrski nalogi je obravnavan pojav utekočinjenja tal, do katerega lahko pride v rahlih, zasičenih, peščenih do meljasto peščenih tleh ob prisotnosti dinamičnih obremenitev (npr. ob potresu). Zaradi porasta pornih tlakov med obremenjevanjem efektivne napetosti upadejo in zemljina izgubi strižno trdnost. Ali bo do porasta pornih tlakov prišlo in v kakšni meri, je odvisno od številnih faktorjev, med katerimi izstopajo zrnavostna sestava, gostotno stanje, prepustnost, starost sedimenta, stopnja saturacije, nivo podzemne vode, jakost potresa, itd. Za potrebe analiziranja dovzetnosti za pojav likvifakcije je treba ovrednotiti jakost dinamične obremenitve zaradi potresnega nihanja s pomočjo količnika ciklične napetosti (CSR) in odpornost zemljine na likvifakcijo z uporabo količnika ciklične odpornosti (CRR) na podlagi terenskih ali laboratorijskih preiskav. V tej nalogi so predstavljene različne metode za ocenjevanje količnika CRR na podlagi SPT, CPT, DMT preiskav in podatkov o hitrosti strižnega valovanja. Naloga vsebuje primerjavo med posameznimi metodami z uporabo podatkov iz terenskih preiskav, zbranih s treh lokacij in sicer bližine HE Brežice, naftnega terminala Porto Romano v Albaniji in mesta Çanakkale v Turčiji.

• Language: Slovenian
• Keywords: likvifakcija, SPT, CPT, DMT, hitrist strižnega valovanja, količnik ciklične odpornosti
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publisher: [Ž. Frantar]
• Year: 2017
• PID: 20.500.12556/RUL-92525
• UDC: 614.84:624.014.2(043)
• COBISS.SI-ID: 8083041
• Publication date in RUL: 06.06.2017

Secondary language

• Language: English
• Title: Comparison of methods for the evaluation of liquefaction potential from in-situ tests

Abstract

The main intention of this master thesis was to present the liquefaction phenomenon, which occurs in loose saturated sands and silty sands during dynamic load (e.g. by earthquake). Due to the increase of pore pressure during loading, effective stresses decrease and soil loses its shear strength. The increase of pore pressure is dependent on wide range of factors such as grain size distribution, relative density, permeability, age of layer, degree of saturation, groundwater level, intensity of earthquake, etc. To analyse the susceptibility of soil deposit upon liquefaction phenomenon it is necessary to evaluate the intensity of dynamic loading due to seismic oscillations in terms of cyclic stress ratio (CSR) and soil resistance by using cyclic resistance ratio (CRR) on the basis of in-situ or laboratory tests. Various methods for evaluating CRR ratio based on SPT, CPT, DMT investigations or shear wave velocity data are presented in this thesis. Thesis contains a comparison of individual methods using data from in-situ tests collected from three different locations namely from HPP Brežice test site, oil terminal Porto Romano in Albania and Çanakkale city in Turkey.

• Keywords: liquefaction, SPT, CPT, DMT, shear-wave velocity, cyclic resistance ratio