Perhitungan Timbunan dan Penurunan Tanah

PERHITUNGAN TIMBUNAN TANAH 1.tinggi timbunan

σ^'v o = H x (γsat – γwat)

= 7.5 (6.5)

= 48.75 kN/m²

tinggi timbunan = elevasi rencana – existing

= 25.950 - 19.51

= 6.44 m

beban perkerasan = 0.69 x 24 = 16.56 kN/m² beban pesawat = 15 kN/m²

mengubah dari kN/m ke m :

=16.56

16 = 1.035 m

= 15

16 = 0.9375 m

timbunan awal= 1.035 + 0.9375 + 6.44

= 8.4125 m

Common = 16 x (8.4125 - 2) = 102.6 kN/m Selected = 17 x 2 = 34

∆ σ ' o = 102.6 + 34 = 136.6 m Se1 = Cc H

1+eo log σ^'o+∆ σ ' o

∆ σ ' o Se1 = 0.274 15

1+1.25 log 48.75+136.6 48.75 Se1 = 1.059 m

Timbunan awal = 8.4125 m

Timbunan akhir = 8.4125 + (1.059 x 1.2)

= 9.6833 m

2.penurunan

Timbunan akhir = 8.4125 + (1.059 x 1.2)

= 9.6833 m

selected = 2 x 17 = 34 m

common = (9.6833 – 2) x 16 = 122.9328 m

∆ σ ' o = 34 + 122.9328

= 156.9328 m Se2 = 0.274 15

1+1.25 log 48.75+156.9328 48.75

= 1.14 m

3.waktu konsolidasi T90 = 0.848

Cv = 0.0012 cm²/detik H²dr = 0.5 x 15

= 7.5 m Tv = Cv .t

H²dr 0.848 = 0.0012.t

7.5

T = 397500000 sec

= 12.6 tahun

4.faktor keamanan