The construction starts from the rectangle shaft with the crown of excavated tunnel passing at distance one diameter under the invert of an existing tunnel.
A wireframe overlay for your finite element models is important when creating work for stress and deformation analyses. You not only want to see that the edge flow and topology are paid close attention to but the individual elements in your work can hold up to a realistic deformations.
Wireframing a Model
Most of the time, the domain elements of the ground will obstruct your view during the model’s stress and deformation assessment of the structural elements. The obtrusive elements can be easily picked and hidden from view.
Exposing the Structural Model
Orthographic preset view are available for ease of orientating a complex model such as a top, front, left or right displays.
A deformation/stress contour shows how much deformation/stress the finite elements are experiencing in different places by using different colors. The changes in the contours can be presented relative to the time domain.
Thirty-two meters diameter circular excavation up to 14 meters deep was supported by a system of ring beams. The surrounding polygonal excavation reached a depth of 8 meters supported by 2 to 3 layers of steel struts and tie-back ground anchors.
In a realistic situation, soil will be able to deform between the soil. A two-dimensional approach will not be able capture the salient behaviour.
Modelling the Ground Anchors
The deformation contours on the retaining walls can be viewed together with the vectors to elucidate their behaviour throughout the construction stages.
The influence of the mechanical properties of the surrounding soils on the load-sharing mechanism in the piled-raft foundation can be examined.
Piled-raft Foundation Model
The challenge is to account for the stiffness disparity between the piles and the surrounding soil during solution.
Elements??? Stiffness Disparity
Flowing strata caused by adjacent excavation will result in shifting of foundation piles centres.
Piles Behaviour during Excavation
The northings and eastings of foundation piles can be imported as points described in a comma-separated values (CSV) file.
Creating Pile Model from CAD Coordinates
The consolidation of a fluid-saturated porous elastic sphere which is subjected to a uniform normal traction applied to the surface, from which pore fluid can drain freely.
Verifying Biot???s Consolidation in a 3D FEM
Mason et al (1991) analyzed systematically the evolution of stress and strain during the consolidation of a porous elastic sphere.
Verifying Biot???s Consolidation in a 2D FEM
3D model was used to determine the maximum bending moment and axial forces developed in the shotcrete and lattice girder lining system at the tunnel intersection.
Modelling Y-junction of a Tunnel
A 3D consolidation analysis was carried out to investigate the settlement in the presence of Singapore River about 40m away.
Sinking a Shaft beside Singapore River.
A 3D settlement contour to determine the impact of the shaft and tunnel construction on the surrounding ground and infrastructures.
Ground Settlement Contours around a Shaft
The ground settlement contours on cutting planes are used to assess the risk of damage to sewer lines located below ground in the tunnel???s vicinity.
Cutting Planes View