Analisis Konsolidasi Dengan Metode Preloading Dikombinasikan Dengan PVD Berdasarkan Perhitungan Analitis dan Plaxis 2d pada Proyek Reklamasi Belawan Phase I

Abstract

Soft soil has poor soil characteristics. In general, these soils have high compressibility, low permeability, and low carrying capacity. Soil improvement using pre-loading and PVD is a soil improvement effort often carried out to accelerate soil consolidation. The initial loading is carried out with the intention of consolidating the soft soil layer with the same or more load compared to the load carried by the soil, both during construction and after. Then, the vertical drain can accelerate consolidation. This analysis was carried out with the intention to be able to find out how much the consolidation has decreased using analytical methods and finite element modeling in PLAXIS 2D, the effect of modeling using a quadratic triangle element (six nodal points) with a quartic triangle element (fifteen nodal points) on the magnitude of consolidation and time calculation process. The methods used in this study are analytical with Terzaghi's theory and finite element method using PLAXIS 2D. Following the analysis results, it is obtained that using the quadratic triangle element of six nodal points and fifteen nodal points does not significantly affect the results of the descent but affects the calculation stage. After analyzing using 2D modeling and supported by a quadratic triangle element with six nodal points and a quartic triangle element with fifteen nodal points, a decrease of - 6.673 meters is obtained for six nodal points. In comparison, for fifteen nodal points, it is -6.669 meters. There was no significant difference between the two methods, which were only 4 mm different. The time needed to calculate the six nodal points is one hour, while the fifteen nodal points are four hours. Thus, these results lead to the conclusion that the calculation of consolidated settlement using PLAXIS 2D tends to approach the actual results in the field with a percentage difference of 0.66%. It differs from the calculation using the analytical method, with a difference of 1.23%. Calculations using PLAXIS 2D with six nodes have more accurate results than fifteen nodes. However, these results are not significant enough because the difference is only 4 mm. By estimating the time needed to determine a count with six nodes, it is about one hour. In contrast, fifteen nodes require four hours, which means that a count using six nodes tends to be recommended for use in the analysis. Addition of nodal points during analysis, namely the time needed during calculations so that it becomes durable due to the fact that there are more and more points being analyzed when using fifteen nodal points