STUDY OF SOIL IMPROVEMENT WITH VACUUM SYSTEM IN KENDAL INDUSTRIAL PARK USING NUMERICAL SIMULATION

• Main Author: Nusanegara, Utama
• Format: Theses
• Language: Indonesia
• Subjects: Teknik sipil
• Online Access: https://digilib.itb.ac.id/gdl/view/65567
• Institution: Institut Teknologi Bandung

Vacuum system modeling for soft clay using finite element program is commonly used by the engineers when they find stability and settlement problems in an improvement area. Finite element program that frequently used is PLAXIS, because of simple modeling. However, the approach used in PLAXIS program doesn’t match the actual conditions of the vacuum system. The vacuum system generally provides negative pore water pressure on the soil, so that suction will occur. While PLAXIS used the concept of water level reduction, this is what makes the lack of accuracy in the model. ABAQUS finite element program can model the real condition of the vacuum system in the field by assigning negative pore water pressure, so it can produce an accurate prediction of the soil improvement. This study started with back-analysis of the axisymmetric model, field monitoring data (settlement plate and N-SPT) is used as a calibration of the model. It was continued with single-drain and multi-drain plane strain modeling with the permeability equivalence equation of Indraratna (1997), Tran-Mitachi (2007), and Kim-Lee (1996). Indraratna’s equation gives the best approach in this research. Analysis that carried out in this study includes the distribution of vacuum pressure in the PVD, the optimum duration of the vacuum system, changes of void ratio due of loading, and lateral movement of the vacuum system. The result of the study shows that vacuum pressure decreases linearly with increasing depth and there is an optimum duration of vacuum system which is indicated by an asymptotic increase in vacuum pressure. This research also produces an equation that describes reduction of void ratio due vacuum system loading.