Evaluation Of Soil Improvement (A Case Study Of Vacuum Consolidation Methodat Palembang – Indralaya Trans Sumatera Toll Road Construction Zone 21 Section 1 Sta 6+650 – Sta 6+950, South Sumatera)

Abstract

The Palembang – Indralaya Toll Road is one of the sections of the Trans Sumatera Toll Road. This specific section of Trans Sumatera Toll Road knowingly has a very problematic existing soil conditions namely soft silty clay soil from the soil surface up until 15 m deep. The goal of this study is to find out whether or not the method used in the project which is the monitoring of settlement using Settlement Plate is accurate in defining the value of the consolidation by comparing the data obtained by the settlement plate used in the project (consolidation settlement, consolidation degree, and soil parameters) with several theoretical analysis namely the analysis of settlement using Terzaghi’s approach, final soil settlement prediction using Asaoka, as well as soil properties recalculation using back analysis. Other than that, this study can be used as reference regarding the implementation of Vacuum Consolidation System literature wise. In performing all of the analysis of this study regarding the Palembang-Indralaya Toll road, secondary data is collected from PT. Hutama Karya Infrastruktur. In this research, the consolidation settlement and consolidation degree analysis is performed using Terzaghi’s approach, Asaoka method, and back analysis to recalculate the soil parameter and the standards used are based off of Kementrian Pekerjaan Umum dan Perumahan Rakyat, Badan Pengatur Jalan Tol 2017) in order to conduct the Vacuum Consolidation Method. Palembang – Indralaya Toll Road from STA 6+650 – 6+950 has an average actual settlement of 604 mm, consolidation degree of >90%, and soil parameters pre vacuum consolidation with Gs of 2.528, sat of 15.14, dry of 8.945, e of1.9835, Cc of 0.53, Cv of 0.0265 m2/day, and Cs of 0.085. After several other analysis namely using Terzaghi’s approach, Asaoka, and back analysis The results obtained from this research are several comparisons of average actual and theoretical settlement estimated at around 0.915 m. As for estimation of final soil settlement using Asaoka observational final soil settlement an average of 0.63 m is obtained, while an average consolidation degree of settlement plate reading obtained at around 94.4% is obtained while consolidation degree obtained from vibrating wire piezometer as big as 100% is obtained. While results of back analysis shows average value of mv as big as 0.00061925, kv of 0.00016125, Ch of 0.016225, Ch/Cv of 0.612, and value of Cc at around 0.062215. With that said it can be safely assumed that throughout the whole analysis the soil could settle even more for about several milimeters according to Asaoka results.