Modelling of seismicity-induced cracking of stone columns using discrete-element-method (DEM), a case study of Eufrasius cathedral, Porec, Croatia

2020 ◽  
Author(s):  
Ali Besharatinezhad ◽  
Ákos Török ◽  
Mohammad Al-Tawalbeh ◽  
Miklós Kázmér
Keyword(s):  
Discrete Element Method ◽  
Failure Mechanism ◽  
Failure Process ◽  
Discrete Element ◽  
Three Dimensions ◽  
Stone Columns ◽  
Stone Column ◽  
Lagrangian Analysis ◽  
Fracture Development ◽  
Element Method

<p>The Eufrasius Cathedral of Poreč in Istria Peninsula, Croatia, was built in the 6th century, The nave collapsed in parts due to the AD 1440 earthquake. Nave and aisles are supported by 18 monolithic columns of Proconnesian marble. Seventeen of the columns bear various fractures, forming two groups: (1) axis-parallel fractures and (2) oblique fractures. Azimuths of dip directions of oblique fractures indicate N-S shaking.</p><p>In this study, the fracture development and cracking of a stone column was modelled using computer code. To model the current fracture pattern and to link it to seismic activity a Lagrangian analysis of continua in three dimensions (FLAC3D) is employed to reveal the non-linear behaviour of the stone column. A 3-Dimensional model based on discrete-element-method (DEM) has been created to study the failure process of the ancient stone column under static and dynamic loads. A combination of vertical and horizontal loads with a dynamic load due to the earthquake has been imposed horizontally. The influence of different parameters such as mechanical properties of rock, the magnitude of the earthquake were also assessed to observe their influence on the failure mechanism of rock. The DEM model was able to describe the observed crack pattern and it has proved the applicability of FLAC3D to describe failure mechanism of stone columns.</p>

scholarly journals Combined DEM-FDM modelling of encased stone column

2019 ◽  
Vol 92 ◽  
pp. 16012
Author(s):  
Ahmadreza Gholaminejad ◽  
Ahmad Mahboubi ◽  
Ali Noorzad
Keyword(s):  
Discrete Element Method ◽  
Cohesive Soil ◽  
Discrete Element ◽  
Stone Columns ◽  
Stone Column ◽  
Coupled Modelling ◽  
Coarse Aggregates ◽  
Discrete Methods ◽  
The Continuum ◽  
Element Method

Combination of the continuum-based numerical methods and the discrete element method (DEM) could be a powerful way of simulating complex problems. This approach benefits from the capabilities of both methods. The main feature of the discrete element method is that the soil grains are considered as individual particles without need to impose any behaviour law in modelling the medium. The limitation of this method is, however, its high computational demand. In continuum based methods, on the other hand, it is impossible to trace micro scale phenomena. According to these facts, combining continuum and discrete methods is an optimal way in approaching geotechnical problems which deal with granular soils. In this approach, the coarse grain zone (medium) is modelled using DEM and the surrounding media are modelled using the continuum methods. Stone columns that are widely used for improving and/or increasing the strength of weak soils could be modelled using this type of coupled simulation. The Coarse aggregates present in the stone column make it appropriate for the coupled modelling. In this paper, the ordinary and encased stone columns have been simulated by combining 2D DEM and finite difference method (FDM). Clump technique was employed to achieve the interlocking of aggregate particles in DEM, and the surrounding cohesive soil was modelled using FDM. The obtained results were validated by the reported experimental results in the literature, indicating that the coupled DEM-FDM method is a robust way to simulate stone columns.

Study on Initial States of Steel Balls in Mill by Discrete Element Method

2012 ◽  
Vol 546-547 ◽  
pp. 120-124
Author(s):  
Ping Zhou ◽  
Jing Hong Du ◽  
Xi Xiang Duan
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Three Dimensions ◽  
Particle Flow Code ◽  
Filling Rate ◽  
Initial State ◽  
State Models ◽  
Steel Balls ◽  
Small Steel ◽  
Element Method

Based on Discrete Element Method(DEM), initial state models of steel balls were establisheded by Particle Flow Code in three Dimensions (PFC 3D), the initial void rate of steel balls at different filling rate were calculated. The results showed that at the same filling rate, the initial void rate of steel balls decreased as steel ball’s diameter decreased. The initial void rate of steel balls with one diameter and grading steel balls both increased gradully as ball filling rate increased, but the initial void rate of grading steel balls were smaller than that of steel balls with one diameter. The Stratification phenomenon will occur after steel balls in grading scheme reached to the initial equilibrium sates, that is, Large steel balls moved near the mill’s center, but small steel balls moved away from the mill’s center and close to the cylinder of mill, which is benifical to improve grinding effeciency.

scholarly journals Application of the discrete element method for modeling of rock crack propagation and coalescence in the step-path failure mechanism

2013 ◽  
Vol 153 ◽  
pp. 80-94 ◽  
Author(s):  
Luis Arnaldo Mejía Camones ◽  
Eurípedes do Amaral Vargas ◽  
Rodrigo Peluci de Figueiredo ◽  
Raquel Quadros Velloso
Keyword(s):  
Discrete Element Method ◽  
Crack Propagation ◽  
Failure Mechanism ◽  
Discrete Element ◽  
Element Method
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