- Design Considerations
- Stress relaxation
- Excavation methods
- Water level
- Ground status (rock quality)
- Earth pressure coefficient (Ko)
GTS NX is fully equipped to model and analyze each phase of tunnel construction, including a simulation of the excavation itself and the installation of supports. Shield TBM analysis can be performed to obtain maximum axial forces, sheer forces, bending moments and radial displacements of the tunnel for each phase of the construction sequence.
GTS NX also enables you perform analyses of various types of tunnel linings such as unsupported rock, shotcrete, and unreinforced concrete systems. You can also take multiple load cases into account such as vertical stresses in soil and horizontal pressures on the tunnel surface. Afterwards you can run the analysis to calculate the resulting forces and moments for each element of the lining.
Linear static analysis assumes ground and rock materials to be linear-elastic materials and uses static analysis to determine the behavioral characteristics when loading is applied. Ground materials only display linear-elastic properties in the early stages of loading, where only a small strain is generated. However, because Linear-elastic analysis does not consider failure and idealizes the stress-strain relationship linearly,it is widely used for simple analysis, such as identifying the stress distribution or concentration in the in-situ ground.
In a broad sense, linear behavior can be viewed as a special form of nonlinear behavior but because linear analysis is convenient and intuitive, linear static analysis is categorized as a separate analysis type. Linear analysis, including Linear dynamic analysis, utilizes the elastic behavior of a defined material for analysis. Also, the non-linear behavior (tension only, compression only and non-linear elastic behavior) of elastic link elements or truss elements are ignored and the elements are used in the analysis as elastic bodies. Consequently, it is useful to use Linear static analysis to observe the approximate behavior of the ground, to organize the initial stage conditions of the construction stage or to conduct tunnel lining analysis.
Particularly, Linear static analysis does not require recursive calculations and hence, it has a short calculation time. GTS NX considers pore pressure in Linear-static analysis and drained and undrained conditions can be assigned to elastic materials for analysis.