Back analyses on prefabricated vertical drain treated ground using plaxis 2D

Abstract

By increasing the industrial developments in Malaysia, there are many construction projects has been carried out. With the development of construction project, it can cause reducing the construction area. Many of the construction nowadays need to be constructed on the soft ground due to the limitation area and it gives the problem of soil settlement and the construction cost directly become double. Prefabricated vertical drains PVD is one of the most commonly used techniques to reduce the time of settlement substantially. The purpose of this study is to study the performance of prefabricated vertical drain (PVD) as treated ground method. This paper presents a case study of the field data associated to settlement of treated soft soil using PVD by comparing with numerical simulation for embankment constructed along highway. This study involved two methods which are field settlement recorded and prediction of settlement using Finite Element Method. PLAXIS 2D analysis showed that the preloading is important to reduce the post construction settlement. Result from the case study indicates the settlement predicted from Finite Element Modelling is slightly higher compare to an actual field settlement. Drain spacing was analysed to evaluate the factor affecting the performance of prefabricated vertical drain. The rate of settlement was increase by decreasing of drain spacing. The installation of PVD at spacing 1.0m gives the optimum rate of settlement followed by spacing 1.4 m, 1.8 m and 2.0 m respectively. In terms of excess pore water pressure, the result showed the pore water pressure were significantly higher and dissipated slowly due to increasing of prefabricated vertical drain spacing. Based on the series of simulation conducted, it was found that the prefabricated vertical drain is effective pre-construction countermeasure for increasing ground stability.