Συμβολή στην ανάλυση των εκσκαφών με την μέθοδο των πεπερασμένων στοιχείων

THE SIMULATION OF AN EXCAVATION, IN THE CONTEXT OF THE FINITE ELEMENT METHOD, INVOLVES THE ANALYSIS OF FACTORS SUCH AS UNLOADING, SINGULARITIES LIKE CORNERS, EXISTENCE OF STRUCTURES BEFORE EXCAVATION, ARTIFICIAL INCLUSION OF GHOST ELEMENTS AND MATHEMATICAL FORMULATION. THE CONVENTIONAL APPROACH BASED ON LINEAR MATERIAL BEHAVIOR OF COMPUTING DISPLACEMENTS AND STRESSES AS IF THE EXCAVATION WERECOMPLETED IN A SINGLE STAGE DOES NOT ACCOUNT FOR PATH DEPENDENCY AND NONLINEARITY INTRODUCED BY INCREMENTAL EXCAVATION. THE OBJECTIVE OF THIS PAPER IS TO PROPOSE AN EFFICIENT, FINITE ELEMENT BASED, NUMERICAL PROCEDURE FOR SIMULATING MULTI-STAGE EXCAVATION FOR SOILS OBEYING AN ELASTOPLASTIC LAW AND TO VERIFY IF THEFINAL SOLUTION IS INDEPENDENT OR NOT WHATEVER THE NUMBER OF EXCAVATION STAGES USED IN THE SIMULATION PROCESS. THE NON-LINEAR FINITE ELEMENT EQUATIONS ARE DERIVED FROM A VARIATIONAL FORMULATION WHICH ACCOUNTS FOR TIME-VARYING PROBLEM DOMAIN, BOUNDARIES AND STATE OF INITIAL STRESSES. THE PROPOSED METHOD SATISFIES THE UNIQUENESS PRINCIPLE IN THE CASE OF ELASTIC MATERIALS. FOR ELASTOPLASTIC MATERIALS SATISFACTION OR NOT OF THE AFOREMENTIONED PRINCIPLE DEPENDS UPON THE MATERIALS PROPERTIES ASSOCIATED WITH THE MODEL OF ANALYSIS AND THE ELEMENT STRESS PATHS PRODUCED BY THE EXCAVATION AS WELL. NUMERICAL EXAMPLES ANALYSIS OF A MONOTONICALLY EXCAVATED DOMAIN USING THE PROPOSED ALGORITHM COMBINED WITH THE DRUCKER-PRAGER YIELD CRITERION AND AN ELASTIC WORK-HARDENING PLASTIC CAP MODEL APPEARS TO LEAD TO THE FOLLOWING CONCLUSIONS: - THE SAME SOLUTION CAN BE ACHIEVED, INDEPENDENTLY OF THE EXCAVATION STAGES, ONLY IF AN ELASTIC STRESS PATH IS PRODUCED BY THE EXCAVATION. - IN THE CASE THAT AN EXCAVATION CAUSES AN ELASTIC PERFECTLY PLASTIC STRESS PATH FOR SEVERAL INTEGRATION POINTS THE SINGLE STAGE ANALYSISIS UNABLE TO TAKE INTO ACCOUNT THE STRESSES REDISTRIBUTION EFFECT AND THE ARISEN TOPOLOGY MODIFICATION. IT CAN BE USED HOWEVER FOR CASES OF NOT TOO CRUDE ELASTOPLASTIC STRESS PATHS IN WHICH GIVES ALMOST SAME RESULTS.

Grantor dc:publisher

Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)

Year dc:date

1991

Author dc:creator

• Κωμοδρόμος, Αιμίλιος

• ALGORITHM FOR SIMULATING EXCAVATIONS
• ELASTOPLASTIC BEHAVIOR
• Failure criterion
• Finite elements method
• NON LINEAR BEHAVIOR OF SOIL
• Numerical analysis
• STRESS PATH
• ΑΛΓΟΡΙΘΜΟΣ ΠΡΟΣΟΜΟΙΩΣΗΣ ΕΚΣΚΑΦΩΝ
• Αριθμητική ανάλυση
• ΔΙΑΔΡΟΜΗ ΤΑΣΕΩΝ
• ΕΛΑΣΤΟΠΛΑΣΤΙΚΗ ΣΥΜΠΕΡΙΦΟΡΑ
• Κριτήριο θραύσης
• Μέθοδος πεπερασμένων στοιχείων
• Μη γραμμική συμπεριφορά εδαφών
• Engineering and Technology
• Civil Engineering
• Επιστήμες Μηχανικού και Τεχνολογία
• Επιστήμη Πολιτικού Μηχανικού

Language dc:language

gre

Identifier

10.12681/eadd/1723

OAI identifier oai:identifier

oai:10442/1723