Susceptibility of Clay Core to Cracks in Rockfill Dams by Finite Element Modeling

2007 ◽  
Vol 18-19 ◽  
pp. 35-41 ◽  
Author(s):  
S.O. Osuji ◽  
B.U. Anyata

The behaviour of the core of rockfill dam with slanting clay core was investigated with the Jebba main dam, Nigeria as a case study. The stress-deformation behavior of the dam was studied using the finite element mathematical modeling technique. The actual fill properties were utilized and two loading scenarios-no water and full reservoir operations-were investigated. At full reservoir, the actual seepage line, as recorded over the years was used. The linear total stress analysis using the finite element method of analysis was employed to analyze the dam section. Following the finite element mathematical modeling and computer simulations of the models, deformations and stresses distributions were determined. The results showed that the observed longitudinal cracks at the Jebba main dam crest are as a result of potential cracks in the dam core section. The cracks observed at the crest, from analysis, commenced from the dam’s core upstream face, downstream face and core crest. This may have resulted from probable hydraulic fracturing and tensile stresses developments in these regions. The results also showed likely loss of integrity of core due to cracks. However, total collapse may not be experienced but dam performance may be impaired and alarming visible cracks may not be ruled out over time.

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.


Author(s):  
Luis Santos-Correa ◽  
Diego Pineda-Maigua ◽  
Fernando Ortega-Loza ◽  
Jhonatan Meza-Cartagena ◽  
Ignacio Abril-Naranjo ◽  
...  

Buildings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 171
Author(s):  
Angeliki Papalou ◽  
Dimitrios K. Baros

Wildfires have always been a threat to forests and areas of high combustible vegetation. When they are not kept under control, they can spread to residential areas, creating severe damage and destruction. This paper examines the effects of the extreme heat conditions that developed during a wildfire on buildings as a function of their construction type. One of the deadliest wildfires in Greece (July 2018) is considered as a case study, and the damage that occurred to buildings during this event is presented. The temperature of the various structural subsystems in extreme heat conditions was estimated using the finite element method. Parameters that influenced the corresponding temperature distribution were identified. Simple guidelines are given to prevent or reduce damage in buildings exposed to wildfires.


2020 ◽  
Vol 12 (3) ◽  
pp. 974
Author(s):  
Paweł Lonkwic ◽  
Krzysztof Przystupa ◽  
Tomasz Krakowski ◽  
Hubert Ruta

This article presents the results of the structure optimization for the power unit carrying frame of a friction lift by means of numerical calculations using the finite element method (FEM). Optimization analysis covered the frame structure. The analysis was focused on strength optimization with the use of a remote load and on manufacturing optimization with attention paid to the operating times necessary to complete the production process of the carrying frame subassemblies. The Solidworks simulation program was used to optimize the frame in terms of the strength criterion. The program allowed both quantitative and qualitative assessments of the frame material effort before and after optimization.


2021 ◽  
Vol 316 ◽  
pp. 917-922
Author(s):  
Irina Volokitina ◽  
Evgeniy Panin ◽  
Kanat Tolubaev

In this paper the methods of mechanical testing of metal and the possibility of their implementation, using mathematical modeling by the finite element method in Deform software package, are considered. As the studied parameters, both the strength indicators (yield strength, tensile strength, Brinel micro-hardness), and the plasticity indicator (the number of kinks before the crack is formed), were studied. The values obtained in the simulation have a very high convergence with the real data.


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