ANALISA PERBAIKAN SUB-GRADE RUNWAY LAPANGAN TERBANG DENGAN METODE VERTICAL DRAIN ( STUDI KASUS BANDARA TEMPULING DI TEMBILAHAN, PROPINSI RIAU)

Abstract

Soil stabilization for the runway sub-grade in Tampuling Airport, Tembilahan, Riau province is required as the existing soil is in the grouped of peat or soft soil. The compressibility rate of this soil is very height, with the depth of the soft soil of more than 30 meters from its surface. Based on “the worst case scenario” without any soil stabilization treatment, it was estimated that the soil consolidation rate would be 1.7 metre within 20 years period of settlement. In order to speed up consolidation process, the vertical drain method was applied. Design of pre loading technique as well as the calculation of distance between vertical drains is then demonstrated in this paper. It was estimated that the depth of vertical drain would be 18 metres, with the distance between vertical drains is 1.2 metres each; height of pre loading is 4.5 metres. With these design parameters, it was expected that the settlement process would be accelerated by 40 folds (235 months to become 6 months period). Key words: vertical drain, pre-loading, settlement, consolidation, sub-grade.