Vrednotenje potenciala likvifakcije z uporabo rezultatov CPT preiskave : diplomska naloga

Janevski, Antonio (author), Logar, Janko (mentor), Oblak, Aleš (comentor)

Pojav likvifakcija predstavlja izgubo strižne trdnosti oziroma strižne nosilnosti zasičene zemljine zaradi hipnega porasta pornega tlaka kot posledice monotonih, impulzivnih ali ponavljajočih se obremenitev. Potres je eden izmed najbolj pogostih dejavnikov za nastop likvifakcije. V okviru diplomske naloge opišemo osnovni mehanizem izgube strižne trdnosti zemljine, zaradi katerega pride do utekočinjene zemljine, opišemo dve vrsti likvifakcije (likvifakcija s tečenjem in ciklična mobilnost), pri katerih pogojih nastopijo ter značilnosti obeh. Analiziramo, kateri geološki pogoji in pogoji, povezani z materialom, vplivajo na pojav likvifakcije, kriterije določenih avtorjev za nastop likvifakcije ter kako potres kot sprožitelj s svojimi karakteristikami vpliva na pojav likvifakcije. S pomočjo zgodovinskih primerov in teoretičnega znanja opišemo posledice in običajne ukrepe, ki se izvajajo proti nastopu likvifakcije tal. V praktičnem delu naloge smo ovrednotili potencial likvifakcije na podlagi rezultatov CPT preiskave, ki je ena izmed pogostih geotehničnih terenskih preiskav. Dovzetnost do pojava likvifakcije preverjamo na podlagi znanih metod (Robertson in Wride, 1998 ter Boulanger in Idriss, 2014) in rezultate obeh medsebojno primerjamo. Za primerjalne analize smo uporabili podatke iz luke Ploče na Hrvaškem. V okviru naloge smo v kratkem opisali značilnosti lokacije, geološke in seizmološke značilnosti ter zaradi občutljivosti zgornjih slojev na utekočinjenje predlagali sanacijsko rešitev.

• Language: Slovenian
• Keywords: likvifakcija, potres, zemljine, CPT, dinamična obremenitev, dinamična komprimacija, impulzno zgoščevanje
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publisher: [A. Janevski]
• Year: 2017
• PID: 20.500.12556/RUL-92627
• UDC: 624.131.536(043.2)
• COBISS.SI-ID: 8090209
• Publication date in RUL: 22.06.2017

Secondary language

• Language: English
• Title: Evaluation of liquefaction potential using CPT test : graduation thesis

Abstract

Liquefaction represents loss of the shear strength and shear resistance of the saturated soil due to the sudden increase in pore pressure caused by monotonous, impulsive or repeated loads. The earthquake is one of the most common factors for the onset of liquefaction. The thesis describes the basic mechanism of the loss of shear strength of the soil that may result in the ground liquefaction. Two types of liquefaction (soil liquefaction and cyclic mobility) are described together with the conditions for their occurence and the characteristics of both phenomena. The geological conditions and material properties required for liquefaction are presented and the criteria for liquefaction innitiation proposed by some authors are given. The influence of earthquake parameters as a triggering event for liquefaction are also discussed. Historical examples and theoretical knowledge are used to describe the consequences of and the usual measures to be taken against liquefaction. In the practical part of the thesis we evaluate the liquefaction potential using the results of CPT investigation, which is widely used geotechnical in-situ test method. Susceptibility of the ground for the liquefaction occurance was assessed on the basis of known methods (Robertson and Wride, 1998 and Boulanger and Idriss, 2014) and the results of both were compared. The data from port of Ploče in Croatia were used. A short description of the site with its geological and seismological properties is included. Finaly, the remedial measures for the upper sandy layer that was found to be prone to liquefaction, were proposed.

• Keywords: liquefaction, earthquake, soil, CPT, dynamic load, dynamic compaction, rapid impact compaction