doktorska disertacija
Rok Varga (Author), Primož Jelušič (Mentor), Bojan Žlender (Co-mentor)

Abstract

Zemljine in kamnine na mestu, kjer so zgrajeni geotehnični objekti, predstavljajo inženirju negotov element, saj začetno napetostno stanje, predhodne obremenitve in razbremenitve ter prekonsolidacija zemljin niso znane. Prav tako se lastnosti zemljin spreminjajo v vertikalni in horizontalni smeri. Za upoštevanje raznih negotovosti pa se za načrtovanje konstrukcij uporabljajo verjetnostne analize. Za namene, da bi lahko upoštevali to negotovost, smo v doktorski disertaciji razvili celovit pristop za optimalno načrtovanje geotehničnih konstrukcij na podlagi verjetnosti porušitve in stroškov gradnje, z osredotočenostjo na večnamensko optimizacijo. Kadar načrtujemo konstrukcijo na podlagi verjetnosti porušitve, pravimo pristopu verjetnostna analiza ali angleško reliability based design (RBD). Naša razvita metodologija za optimizacijo uporablja genetski algoritem, ki je kodiran z realnimi števili. V doktorski disertaciji smo analizirali številne metode, ki se uporabljajo pri načrtovanju geotehničnih konstrukcij na podlagi verjetnosti porušitve, pri čemer smo predstavili teoretična izhodišča in na primeru horizontalnega zdrsa točkovnega temelja pokazali njihovo kompleksnost. Tako imenovana »razširjena RBD metoda« se je izkazala za inženirjem najbolj prijazno metodo, saj poda kakovostnejše informacije o zasnovi in o porušitvenih mehanizmih. V vseh treh aplikativnih primerih geotehničnih konstrukcij, to so težnostni podporni zid, geotermalni pilot in vpeta vitka oporna konstrukcija, smo pridobili detajlne podatke o kritičnih pogojih nosilnosti za porušitev, kar omogoča inženirjem, da preprečijo specifičen porušitveni mehanizem z dotično spremembo zasnove. V tem smislu smo postavili tudi glavno tezo doktorske disertacije, in sicer, da je možno razviti učinkovito metodologijo za načrtovanje geotehničnih konstrukcij na podlagi verjetnosti porušitve in z večnamensko optimizacijo. Analize in primerjave z načrtovanjem geotehničnih konstrukcij v skladu z Evrokodom, ki upošteva delne količnike varnosti, pa so pokazale, da je razvita metodologija bolj občutljiva na vse spremenljivke in robne pogoje, kar omogoča celovitejšo obravnavo konstrukcij in privede do optimalnih zasnov danih konstrukcij. Tako je bil z razvojem in preizkušanjem metodologije potrjen potencial le-te za praktično uporabo v inženirski praksi, kar bi lahko omogočalo dodatno analizo konstrukcij za večjo zanesljivost in bolj ekonomično gradnjo geotehničnih konstrukcij.

Keywords

verjetnost porušitve;optimizacija;genetski algoritem;geotermalni piloti;geotehnične konstrukcije;doktorske disertacije;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UM FGPA - Faculty of Civil Engineering, Transportation Engineering and Architecture
Publisher: [R. Varga]
UDC: 624.131:519.2(043.3)
COBISS: 220410371 Link will open in a new window
Views: 0
Downloads: 3
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: English
Secondary title: Development of a methodology for the design of geotechnical structures based on probability of failure and multi-objective optimisation
Secondary abstract: The soils and rocks at the site of geotechnical structures represent uncertain elements for engineers because the initial stress state, previous loading and unloading and pre-consolidation of the soil are uncertain. It is also known that soil properties vary spatially. Probability analyses are used to account for these uncertainties in the design of structures. To account for these uncertainties, this dissertation developed a comprehensive approach for the optimal design of geotechnical structures based on the probability of failure and construction costs, with a focus on multi-objective optimization. This approach for the design of structures based on the probability of failure is called Reliability Based Design (RBD). The optimization method we developed uses a genetic algorithm coded with real numbers. In the doctoral dissertation, we have analysed numerous methods used in the design of geotechnical structures based on the probability of failure. We presented theoretical principles and demonstrated their complexity using an example where we determined the resistance of foundations to horizontal slippage. The so-called "extended RBD method" has proven to be the most user-friendly method for engineers as it provides higher quality information on design and failure mechanisms. For all three applied examples of geotechnical structures (gravity retaining wall, geothermal pile and embedded wall), detailed data on the critical bearing capacity conditions for failure were obtained, allowing engineers to prevent certain failure mechanisms by appropriate design changes. In this context, we also formulated the main thesis of the doctoral dissertation, namely that it is possible to develop an effective methodology for the design of geotechnical structures based on the probability of failure and multi-objective optimization. Analyses and comparisons with the design of geotechnical structures according to Eurocode, which considers partial safety factors, have shown that the developed methodology is more sensitive to all variables and boundary conditions, allows a more comprehensive treatment of structures and leads to optimal designs of the given structures. The development and testing of the methodology has thus confirmed the potential for its practical application in engineering practice, which could allow additional analysis of structures for higher reliability and more economical design of geotechnical structures.
Secondary keywords: probability of failure;optimization;genetic algorithm;geothermal piles;geotechnical structures;doctoral dissertations;
Type (COBISS): Doctoral dissertation
Thesis comment: Univ. v Mariboru, Fak. za gradbeništvo, prometno inženirstvo in arhitekturo, Gradbeništvo
Pages: XIV, 145 str.
ID: 23258201