3D numerical investigation of mechanized twin tunnels in soft ground – Influence of lagging distance between two tunnel faces

2016 ◽  
Vol 109 ◽  
pp. 117-125 ◽  
Author(s):  
Ngoc-Anh Do ◽  
Daniel Dias ◽  
Pierpaolo Oreste
Keyword(s):  
Numerical Investigation ◽  
Soft Ground ◽  
Twin Tunnels

3D numerical investigation on the interaction between mechanized twin tunnels in soft ground

2014 ◽  
Vol 73 (5) ◽  
pp. 2101-2113 ◽  
Author(s):  
Ngoc-Anh Do ◽  
Daniel Dias ◽  
Pierpaolo Oreste
Keyword(s):  
Numerical Investigation ◽  
Soft Ground ◽  
Twin Tunnels

Three-dimensional numerical investigation of multifaced tunneling in water-bearing soft ground

2008 ◽  
Vol 45 (10) ◽  
pp. 1467-1486 ◽  
Author(s):  
Chungsik Yoo ◽  
Sun-Bin Kim
Keyword(s):  
Numerical Investigation ◽  
Three Dimensional ◽  
Element Model ◽  
Soft Ground ◽  
Single Pile ◽  
Ground Settlement ◽  
Axial Loads ◽  
Groundwater Drawdown ◽  
Fully Coupled ◽  
Ground Settlements

This paper presents the results of a numerical investigation of the performance of multifaced tunneling under a pile-supported building in water-bearing soft ground. Special attention was paid to the effect of tunneling and groundwater interaction on the tunneling performance. A fully coupled three-dimensional (3D) stress – pore pressure finite element model was adopted to realistically capture the mechanical and hydrological interaction between the tunneling and groundwater. The results indicate that the groundwater drawdown during tunneling yields a considerably larger settlement-affected zone than for cases with no groundwater drawdown, with a tendency for large portions of ground settlement and groundwater drawdown to be completed before the tunnel passes a monitoring section. Also revealed is that the presence of a building tends to reduce the ground settlements and cause subsurface settlements more or less uniformly with depth. It is shown that the lining deformation, and thus its stresses are not significantly affected by the presence of the building for the multifaced tunneling considered in this study. Axial loads in the piles supporting the building tend to either increase or decrease depending on the pile location relative to the tunnel axis. The patterns of changes in pile axial loads are different from the results of previous studies concerning a single pile.

Three-dimensional numerical simulation of a mechanized twin tunnels in soft ground

2014 ◽  
Vol 42 ◽  
pp. 40-51 ◽  
Author(s):  
Ngoc-Anh Do ◽  
Daniel Dias ◽  
Pierpaolo Oreste ◽  
Irini Djeran-Maigre
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Soft Ground ◽  
Twin Tunnels

scholarly journals Three-dimensional Numerical Investigation of the Interaction Between Twin Tunnels

2021 ◽  
Author(s):  
Filippos Chortis ◽  
Michael Kavvadas
Keyword(s):  
Numerical Investigation ◽  
Interaction Effect ◽  
Three Dimensional ◽  
Horizontal Stress ◽  
Potential Interaction ◽  
Axial Forces ◽  
Wide Range ◽  
Shotcrete Lining ◽  
Primary Support ◽  
Twin Tunnels

Abstract The construction of twin tunnels is an obligatory guideline and a prevailing practice in either conventional or mechanized tunneling. Nevertheless, most of the design methods for calculating the tunnel loads focus on single tunnels, thus, neglecting the potential interaction between neighboring tunnels. The effect of such interaction can be significant, especially for closely-spaced twin tunnels. In this context, this paper investigates via parametric 3D Finite Element (3D-FE) analyses the interaction between deep, parallel-twin, circular and non-circular tunnels excavated with a conventional (non-TBM) method and supported with shotcrete lining. The numerical investigation focuses on the axial forces acting on the primary support of the tunnels by examining the effect of a wide range of geometrical (pillar width, overburden height, tunnel diameter and section (shape), lagging distance), geotechnical (strength and deformability of the surrounding rockmass, horizontal stress ratio), structural (thickness and deformability of the shotcrete lining) and construction parameters (full- or partial- face excavation and support of the tunnels). The results of the analyses indicate that the construction of the subsequent tunnel influences the loads of the precedent. The stress state of the single tunnel is used as the reference for the quantification of the interaction effect. The output is presented in normalized design charts of the quantified interaction effect on the axial forces, versus key geomaterial and geometry parameters to facilitate preliminary estimations of primary support requirements for twin tunnels.

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