الفهرس 
Discharge capacity
East Port Said Ground Improvement ProjectOnly 14 pages are availabe for public view
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Abstract
Dealing with soft soil deposits imposes various geotechnical challenges. Excessive settlement and low shear strength are some of the main characteristics of soft soils mainly caused due to their large void ratio. Different soil improvement methods can be used to overcome these problems, including the preloading method. Preloading is one of the most applied soil improvement techniques due to its simplicity, reliability, and economic efficiency compared to other methods. Soft soil deposits are characterized by low permeability; thus, the preload needs to be applied for a long time to reach the necessary consolidation. Since the 1980s, Prefabricated Vertical Drains (PVDs) have been extensively utilized as a method of accelerating the preloading.
Numerical modeling provides an adequate tool to investigate the behavior of the soft soil layers both during and after preloading. Moreover, the long-term settlement of the soil layers due to creep can be predicted. Three-dimensional finite element analysis can give an excellent depiction of the behavior provided that accurate representation of both the soft soil and the PVDs is applied.
The research utilizes the finite element analysis code PLAXIS 3D 2018 in investigating a case study at Changi East reclamation project in Singapore. The case includes two identical trial embankments constructed on soft soil formations. The soft soil deposits under both embankments are treated using preloading, while PVDs were utilized under the main embankment only. The smear of the soil layers surrounding the PVDs, the well-resistance, and the effect of the PVD buckling are all considered in the FEM. Furthermore, simulating the soft soil behavior using different constitutive models is explored. The analysis indicates that utilizing the Soft Soil Creep model (SSC) to predict the behavior of the soft soil deposits is most appropriate.
In order to examine the various factors affecting the required duration for preloading and also the residual settlement of the structure itself, a parametric study utilizing the calibrated numerical model is performed. The results indicate the significant influence of the length and spacing of the PVDs on both the duration of the consolidation process and the residual settlement, while the configuration of the PVDs is found to be of minimal importance.
The verified modeling procedures are then used to investigate the efficiency of using the preloading method assisted by PVDs to improve the soft soil deposits in the East Port Said area in Egypt. Furthermore, optimization of the required lengths and spacings for the PVDs is explored. The investigations show that installing PVDs increases the efficiency of the preloading as a reduction in the residual settlement occurs. Furthermore, optimized geometry for the utilized PVDs is suggested.