Abstract

Pejagan Pemalang Toll Road is the highway with toll that passes through Tegal city and Pemalang regency. This area has soft soil such as very soft clay, soft clay, etc. The soil improvement is needed to reach the suitable excess pore pressure which can make optimum moisture content to strengthen the soil. The soil improvement is using Limestone, Prefabricated Drain and Geotextile are methods available that can reach faster consolidation 90% and avoids collapse with safety factor as the guidance criteria. In this study, the numerical software of Plaxis 8.2 with soil parameters from SPT correlation was incorporated for a series of 2D model. The result of the cross section model without soil improvement shows collapse at embankment 5 m height and soil improvement without limestone is collapse at embankment 7 m height. T90 on the cross section at stage of Consolidation 5 and the long section at stage of Loads of 90.4 kPa. The settlement on cross section at Consolidation 5 stage with soil improvement is 103.5 x 10-2 m with excess pore pressure -9.52 kPa and safety factor 1.2522. The settlement on long section at Loads of 90.4 kPa stage is 907.36 x 10-3 m with excess pore pressure 16.84 kPa and safety factor 2.353. The safety factor on the cross section and the long section with soil improvement is more than 1.2 as criteria design.