Usually, roads and structures construction on soft ground are related to the stability and usage problems due to long period of consolidation process if the soft ground is not improved. The ground improvement by vertical drain methods is not perfectly considered as theoretical calculations because of disturbance of soils by the installation of drain materials, sampling for testing, and etc. In addition, the efficiencies of the vertical drain methods may be affected by ground properties such as non-homogeneity and anisotropy. Because of these reasons, the estimates results are usually different from the measured (monitored).
In order to predict the real behaviors of the soft grounds it is necessary to understand the accurate soils engineering properties, application of the ground improvement method and process, and the construction sequence of drain methods. Therefore, monitoring data during construction and maintenance process is very important.
The thickness of soft soil layer that is needed improvement is generally about 25m in Busan New Port. However, a large area of ground in Busan New Port has been improved up to below 25m.
Plastic Board Drain (PBD), one of the vertical drain methods, was applied at the North Container Terminal in Busan New Port to improve the soft ground. The design theory of the PBD method was described in detail here. The efficiencies of the adopted method (PBD) were validated by comparison with the measured results obtained from CPT, RI-Meter, and field vane tests.
It is expected that the output of this research is a useful documentation for design and analysis in the case of a similar soft ground improvement project in future.