A FEM-based numerical study of responses of underground openings subject to plane, cylindrical, compressive and tensile waves

2016 ◽  
pp. 355-360
Author(s):  
Z Liao ◽  
N Lam ◽  
J Zhu
1992 ◽  
Vol 29 (2) ◽  
pp. 188-194 ◽  
Author(s):  
B. Stimpson ◽  
M. Ahmed

The design of underground openings in horizontally layered strata on the basis of classical linear arching theory assumes the ultimate load capacity of the roof is limited by crushing or compressional failure at the centre of the arch or at the abutments. In this study, physical model tests on limestone, granite, and potash beams revealed a progressive failure mechanism dominated by discrete tensile fracturing, a quite different failure process to that assumed by classical theory. Subsequently, discrete crack propagation finite element analysis successfully simulated the failure mechanisms observed in the physical models. Key words : rock mechanics, underground design, roof stability, Voussoir arch, fracture.


1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.


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