**GTS NX**is a comprehensive finite element analysis software package that is equipped to handle the entire range of geotechnical design applications including deep foundations, excavations, complex tunnel systems, seepage analysis, consolidation analysis, embankment design, dynamic and slope stability analysis. GTS NX also has an advanced user friendly modeling platform that enables unmatched levels of precision and efficiency. As the next generation geotechnical analysis software, midas GTS NX features the newest development in cutting-edge computer graphics and analysis technology. GTS NX fully supports the latest 64-bit OS Graphic user interface. The intuitive interface will enable new users to easily integrate the software in their work process. The fast analysis speed, outstanding graphics, and output capabilities will provide users with a new and advanced level of geotechnical design.

**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.

**All physical phenomena includes non-linearity.**Ground or structural behaviors are not an exception. Non-linear static analysis is used to simulate the behavior of ground considering such non-linearity, when the change with time is small and can be ignored. GTS NX considers the following non-linearity.

**Non-linearity of material :**This occurs when the stress-strain relationship is non-linear. Most ground materials have this non-linearity.

**Geometric non-linearity:**If the displacement-strain relationship is non-linear, the linear assumption is no longer applicable when the displacement is large, or the rotational deformation is large.

**Non-linearity of load and boundary:**Non-linearity that includes the non-linear behavior at an interface, or non-linearity caused by the direction change of a load due to strain, caused by forces such as the follower force. GTS NX can consider all non-linearity mentioned above in analysis. Non-linear analysis can take a long time for complex non-linear systems because repeated calculations are conducted. Hence for the practicality, considering appropriate non-linearity can result in analysis results that simulate non-linear behavior, while maintaining the accuracy with little computational cost.