3D finite element modeling of surface excavation and loading over existing tunnels

Download
2007
Kaçar, Onur
The influence of the surface excavation and loading on the existing tunnels has been investigated using a Finite Element Method program, Plaxis 3D Tunnel. A parametric study has been carried out where the parameters were the depth of the surface excavation, the eccentricity of the excavation with respect to the tunnel axis, the height of the embankment fill and the stiffness of the soil. It is found that, excavations over the existing tunnels have a negative effect on the tunnel lining capacity since the unloading due the excavation reduces the normal forces and increases the bending moments. On the other hand, it is found that surface loading within the limits considered in this study is not critical in terms of the tunnel stability due to the increase in normal forces and decrease in bending moments.

Suggestions

3D Simulation of Dynamic Delamination in Curved Composite Laminates
Ata, Tamer Tahir; Çöker, Demirkan (Elsevier BV; 2019-01-01)
In this study, dynamic fracture of curved carbon fiber reinforced plastic (CFRP) laminates under quasi-static loading is investigated using explicit three dimensional (3D) finite element method in conjunction with Cohesive Zone Modelling (CZM). The simulations are based on the experimental studies conducted by Tasdemir (2018). Three dimensional finite element models of two different ply architectures (unidirectional and fabric laminate) are generated corresponding to the experimental configurations. The com...
Analytical study on seismic retrofitting of reinforced concrete buildings using steel braces with shear link
Durucan, Cengizhan; Dicleli, Murat (2010-10-01)
This paper is focused on a proposed seismic retrofitting system (PRS) configured to upgrade the performance of seismically vulnerable reinforced concrete (RC) buildings. The PRS is composed of a rectangular steel housing frame with chevron braces and a yielding shear link connected between the braces and the frame. The retrofitting system is installed within the bays of an RC building frame to enhance the stiffness, strength and ductility of the structure. The PRS and a conventional retrofitting system usin...
Mathematical modeling of steam-assisted gravity drainage
Akın, Serhat (Society of Petroleum Engineers (SPE), 2005-01-01)
A mathematical model for gravity drainage in heavy-oil reservoirs and tar sands during steam injection in linear geometry is proposed. The mathematical model is based on the experimental observations that the steam-zone shape is an inverted triangle with the vertex fixed at the bottom production well. Both temperature and asphaltene content dependence on the viscosity of the drained heavy oil are considered. The developed model has been validated with experimental data presented in the literature. The heavy...
Mathematical modeling of steam-assisted gravity drainage
Akın, Serhat (Elsevier BV, 2006-03-01)
A mathematical model for gravity drainage in heavy-oil reservoirs and tar sands during steam injection in linear geometry is proposed. The mathematical model is based on experimental observations that the steam zone shape is an inverted triangle with the vertex fixed at the bottom production well. Both temperature and asphaltene content dependence of viscosity of the drained heavy oil and their impact on heavy oil production are considered. The developed model has been validated using experimental data pres...
Optimum design of high-rise steel buildings using an evolution strategy integrated parallel algorithm
Hasançebi, Oğuzhan; Kurç, Özgür (Elsevier BV, 2011-11-01)
The present study addresses a parallel solution algorithm for optimum design of large steel space frame structures, in particular high-rise steel buildings. The algorithm implements a novel discrete evolution strategy optimization method to effectively size these systems for minimum weight according to the provisions of ASD-AISC specification and various practical aspects of design process. The multitasking environment in the algorithm rests on a master-slave model based parallelization of the optimization ...
Citation Formats
O. Kaçar, “3D finite element modeling of surface excavation and loading over existing tunnels,” M.S. - Master of Science, Middle East Technical University, 2007.