- Design Considerations
- Initial and long term stability
- Lateral ground flow
- Slope failure
- Differential settlements
- Reduction of bearing capacity
- Improvement methods
Softground is very compressible deposits such as Clay, silty Clay,clayey Silt. Because these kinds of deposit have very low permeability , waterlevel is generally located on the ground surface. And if constructing the embankment over the soft ground or excavating some area, it can result in lots of settlement or failure of the ground.
But, these days, we have to construct embankment over these soft ground due to the lack of suitable land for infrastructures and other developments. So, we have to make a decision for optimized improvement method. GTS NX calculates time-dependent consolidation settlement through staged consolidation analysis. Staged fully coupled analysis can be performed in the same sequence as field construction and it is possible to set actual time durations to the modeled stages so can reflects changes in excessive pore water pressure and water level in real time. In addition, the integration capabilities in GTS NX allow for a wide range of stability analyses such as embankment slope, adjacent structures and the interaction of reinforcements and soil materials.
Consolidation analysis is an analytical method that calculates the behavior of pore water pressure when it resists external loading, when excess pore water pressure occurs and as the excess pore water pressure reduces with time for an undrained condition.
Pore water pressure in the ground with a small osmotic coefficient instantaneously displays the same behavior as the undrained condition. Hence, it bears most of the compressive load by the created excess pore water pressure, according to the change in load state. However, as time goes by, excess pore water pressure is re-distributed and if there is a drainage boundary, the excess pore water pressure decreases gradually.
Because of this, the load previously resisted by the excess pore water pressure is gradually resisted by the soil frame, causing gradual deformation of the soil frame and increasing effective stress within the frame. The increase in effective stress leads to the deformation of soil structure and this deformation is accumulated in the gravitational direction, eventually displaying settlement behavior in the gravitational direction with time elapse.
This gradual increase in deformation creates settlement at the base of structural foundation and differential settlement at the base foundation greatly affects the stability and safety of the structure.