BAB I - ANALISIS STABILITAS LERENG JALAN MENGGUNAKAN PERHITUNGAN BISHOP, FELLENIUS (MANUAL) DAN PROGRAM GEOSTUDIO (Studi Kasus : Jalan Tol Bawen – Salatiga Sta 29+400) - Unissula Repository

  DAFTAR ISI HALAMAN JUDUL .......................................................................................... i HALAMAN PENGESAHAN ............................................................................ ii SURAT PERNYATAAN KEASLIAN .............................................................. iii BERITA ACARA ............................................................................................... vi

MOTTO DAN PERSEMBAHAN ..................................................................... vii

KATA PENGANTAR ........................................................................................ x ABSTRAK .......................................................................................................... xi

DAFTAR ISI ...................................................................................................... xiii

DAFTAR GAMBAR .......................................................................................... xvi

DAFTAR TABEL .............................................................................................. xviii

DAFTAR RUMUS ............................................................................................. xix

DAFTAR NOTASI............................................................................................. xx

DAFTAR LAMPIRAN ...................................................................................... xxii

  BAB I PENDAHULUAN ............................................................................ 1

  1.1 LatarBelakang .......................................................................... 1

  1.2 Rumusan Masalah .................................................................... 3

  1.3 Tujuan Kajian ........................................................................... 3

  1.4 Ruang Lingkup Penelitian ......................................................... 4

  1.5 Peta Lokasi ............................................................................... 4

  1.6 Keaslian Kajian ........................................................................ 4

  1.7 Sistematika Penulisan ............................................................... 5

  BAB II TINJAUAN PUSTAKA ................................................................... 6

  2.7.2 Faktor Ketidakstabilan Lereng ......................................... 23

  3.1 Pengertian Umum ..................................................................... 43

  BAB III METODE PENELITIAN ................................................................ 43

  2.9.2 Slope/W .......................................................................... 40

  2.9.1 Pengertian Geo Studio ..................................................... 39

  2.9 Aplikasi Geo Studio ................................................................. 39

  2.8.2 Metode Perhitungan Manual Lereng ................................ 34

  2.8.1 Analisa Kestabilan Lereng .............................................. 32

  2.8 Analisa Lereng ......................................................................... 32

  2.7.5 Faktor Keamanan Lereng ................................................. 30

  2.7.4 Klasifikasi Kemiringan Lereng ........................................ 29

  2.7.3 Faktor Kemantapan Lereng .............................................. 26

  2.7.1 Pengertian Lereng ............................................................ 22

  2.1 Tanah ....................................................................................... 6

  2.7 Lereng ...................................................................................... 22

  2.6.3 Jenis Longsoran ............................................................... 19

  2.6.2 Klasifikasi Longsoran ...................................................... 15

  2.6.1 Pengertian Longsoran ...................................................... 14

  2.6 Longsoran................................................................................. 14

  2.5.2 Pemadatan Tanah ............................................................ 13

  2.5.1 Pengertian Timbunan ....................................................... 12

  2.5 Timbunan ................................................................................. 12

  2.4 Parameter Tanah ....................................................................... 9

  2.3 Sifat-Sifat Tanah ....................................................................... 8

  2.2 Profil Tanah .............................................................................. 7

  3.2 Tipe Penelitian .......................................................................... 43

  3.4 Cara Penelitian ......................................................................... 47

  3.5 Tahap Persiapan ....................................................................... 51

  3.6 Metode Analisis Data ............................................................... 52

  3.7 Penentuan Parameter Tanah ...................................................... 53

  BAB IV PEMBAHASAN ............................................................................... 54

  4.1 Gambaran Umum ..................................................................... 54

  4.2 Analisis Kelongsoran Secara Manual ........................................ 58

  4.2.1 Perhitungan Metode Bishop ............................................ 58

  4.2.2 Perhitungan Metode Fellenius ......................................... 69

  4.3 Analisis Kelongsoran Menggunakan Program GeoSlope .......... 75

  4.4 Perbandingan Hasil Safety Factor (SF) ..................................... 89

  BAB V PENUTUP ........................................................................................ 93

  5.1 Kesimpulan .............................................................................. 93

  5.2 Saran ........................................................................................ 93

  DAFTAR PUSTAKA LAMPIRAN

  DAFTAR GAMBAR

Gambar 1.1 Timbunan Tanah Lokasi Tol Bawen-Salatiga ............................... 3Gambar 1.2 Peta Lokasi Tol Bawen-Salatiga .................................................... 4Gambar 2.1 Lapisan Tanah ............................................................................... 7Gambar 2.2 Klasifikasi Tekstur Tanah .............................................................. 8Gambar 2.3 Pemadatan Untuk Timbunan Tinggi .............................................. 12Gambar 2.4 Longsoran Bidang (Plane Failure) ................................................ 16Gambar 2.5 Longsoran Baji (Wedge Failure) ................................................... 17Gambar 2.6 Longsoran Guling (toppling Failure) ............................................ 18Gambar 2.7 Longsoran Busur (Circular Failure) .............................................. 18Gambar 2.8 Tipe Jatuhan (Falls) ..................................................................... 19Gambar 2.9 Tipe Robohan (topples) ................................................................ 20Gambar 2.10 Tipe Gelincir (slides) ..................................................................... 20Gambar 2.11 Tipe Aliran (flows) ........................................................................ 21Gambar 2.12 Tipe Rayapan (creeping) ............................................................... 21Gambar 2.13 Lereng Jalan Tol Bawen

• – Salatiga ................................................ 22

Gambar 2.14 Faktor Keamanan Lereng .............................................................. 31Gambar 2.15 Beberapa Upaya Peningkatan Stabilitas Lereng ............................. 33Gambar 2.16 Beberapa Upaya Peningkatan Stabilitas Lereng ............................. 34Gambar 2.17 Analisa Stabilitas Lereng ............................................................... 34Gambar 4.2 Stratigafi Tanah dan Potongan Melintang Jalan STA 29+400 ........ 56Gambar 4.3 Bidang Gelincir Perhitungan Manual ............................................. 57Gambar 4.4 Jendela Layar Utama Plaxis........................................................... 75Gambar 4.5 Jendela Gambar Permodelan ......................................................... 75Gambar 4.6 Jendela Gambar Titik-titik Koordinat Permodelan ......................... 76Gambar 4.7 Jendela Layar Utama GeoSlope ..................................................... 76Gambar 4.8 Jendela Membuat Permodelan ....................................................... 81Gambar 4.9 Jendela Pengaturan Kertas Kerja ................................................... 81Gambar 4.10 Jendela Pengaturan Skala Gambar ................................................. 82Gambar 4.11 Jendela Pengaturan Sumbu Gambar............................................... 82Gambar 4.12 Jendela Gambar Titik-itik Koordinat Permodelan .......................... 82Gambar 4.13 Jendela Penggabungan Titik-Titik Koordinat ................................. 83Gambar 4.14 Jendela Model Gambar Lereng ...................................................... 83Gambar 4.15 Jendela Memasukkan Data Tanah.................................................. 84Gambar 4.16 Jendela Memasukkan Data Tanah.................................................. 84Gambar 4.17 Jendela Memasukan Material Tanah .............................................. 85Gambar 4.18 Jendela Menyamakan Lapisan Tanah ............................................ 85Gambar 4.19 Jendela Hasil Lapisan Tanah dan Material Tanah Disamakan ........ 85Gambar 4.20 Jendela Geoslope........................................................................... 86Gambar 4.21 Jendela Parameter Tanah ............................................................... 86Gambar 4.22 Jendela Analisis Stabilitas Lereng ................................................. 87Gambar 4.24 Jendela Pengecekan Keeroran ....................................................... 88Gambar 4.25 Jendela Run ................................................................................... 88Gambar 4.26 Jendela Kontur Lereng .................................................................. 89

  DAFTAR TABEL

Tabel 2.1 Hubungan Antara Nilai N-

SPT dan Berat Jenis Tanah Jenuh (γsat) .. 10

Tabel 2.2 Hubungan Antara Kepadatan, Berat Jenis Tanah Kering,, Nilai N SPT

  .......................................................................................................... 10

Tabel 2.3 Klasifikasi Tanah dari Data Sondir .................................................... 11Tabel 2.4 Kriteria Perencanaan Angka Keamanan Lereng ................................. 23Tabel 2.5 Klasifikasi Kemiringan Lereng .......................................................... 30Tabel 2.6 Pembagian Kemiringan Lereng Berdasarkan Klasifikasi USSSM dan

  USLE ................................................................................................ 30

Tabel 2.7 Hubungan Nilai Faktor Keamanan Lereng dan Intensitas Longsor ..... 33Tabel 3.1 Diagram Alir Perencanaan ................................................................. 45Tabel 3.2 Hasil Uji Coring/Bor Log pada titik BW-32 ....................................... 52Tabel 3.3 Parameter Desain Potongan Melintang ............................................... 53Tabel 4.1 Parameter Desain Material Pada Lereng Jalan Tol Bawen-Salatiga ... 55Tabel 4.2 Perhitungan Faktor Keamanan Lereng Metode Bishop ....................... 67Tabel 4.3 Perhitungan Faktor Keamanan Lereng Metode Fellenius ................... 74Tabel 4.4 Koordinat Pada Plaxis v8.2 STA 29+400 ........................................... 78Tabel 4.5 Hasil Perbandingan Analisis Kestabilan Lereng ................................. 89

  DAFTAR RUMUS

  Rumus 2.1 Pembuatan Peta Lereng...................................................................... 29 Rumus 2.2 Perhitungan Faktor Keamanan Lereng ............................................... 31 Rumus 2.3 Faktor Aman Dengan Resultan Gaya-Gaya Antar Irisan Dia baikan .. 35 Rumus 2.4 Lengan Momen Dari Berat Massa Tanah Tiap Irisan ......................... 35 Rumus 2.5 Momen Yang Menahan Tanah Akan Longsor .................................... 35 Rumus 2.6 Faktor Aman Dengan Menahan Tanah Akan Longsor ...................... 35 Rumus 2.7 Faktor Aman Dengan Air Pori ........................................................ 36 Rumus 2.8 Faktor Aman Dengan Persamaan Kuat Geser ................................. 37 Rumus 2.9 Faktor Aman Dengan Kesimbangan Batas ....................................... 37 Rumus 2.10 Faktor Aman Dengan Dasar Bidang Longsor ................................... 37 Rumus 2.11 Nilai Banding Tekanan Pori ............................................................. 38 Rumus 2.12 Faktor Keamanan Untuk Analisis Stabilitas Lereng Cara Bishop ...... 38 Rumus 2.13 Menentukan Nilai Fungsi Mi ............................................................ 38 Rumus 3.1 Faktor Aman Dengan Dasar Bidang Longsor ..................................... 46 Rumus 3.2 Nilai Banding Tekanan Pori ............................................................... 46 Rumus 3.3 Faktor Keamanan Untuk Analisis Stabilitas Lereng Cara Bishop ....... 47 Rumus 3.4 Faktor Aman Dengan Resultan Gaya-Gaya Antar Irisan Diabaikan .. 47 Rumus 3.5 Lengan Momen Dari Berat Massa Tanah Tiap Irisan ......................... 48 Rumus 3.6 Momen Yang Menahan Tanah Akan Longsor .................................... 48

  Rumus 3.8 Faktor Aman Dengan Air Pori ......................................................... 48

  S Besar Sudut Lereng n Jumlah Kontur Yang Memotong Tiap Diagonal Jarring ki Kotur Interval a Panjang Diagonal Jarring Dengan Panjang Usuk 1 cm F Faktor keamanan lereng L Panjang segmen bidang gelincir (m)  Gaya Ketahanan Geser Atau Tahanan Geser Sepanjang L (ton/m

  2

  ) s Gaya Dorong Geser (ton/m

  2

  ) c Kohesi Massa Lereng (ton/m

  2

  ) 

  Sudut Geser Dalam Massa Lereng (derajat) W Bobot Massa Diatas Segmen L (ton)  Tekanan Pori (  air x h x L) h Panjang Garis Ekuipotensial Ketitik Berat L (m)  Sudut Yang Dibentuk Oleh Bidang Gelincir Dengan Bidang Horizontal

  (derajat) R Jari-Jari Lingkaran Bidang Longsor N Jumlah Irisan W

  i

  Berat Massa Tanah Irisan ke-i  Sudut Yang Didefinisikan F Faktor Aman c Kohesi Tanah (kN/m

  2

  ) 

  Sudut Gesek Dalam Tanah (derajat) ɑ u i Tekanan Air Pori Pada Irisan ke-i (kN/m

  2

  )  Sudut Yang Didefinisikan σ

  Tegangan Normal Total Pada Bidang Longsor u Tekanan Air Pori Fk Faktor Keamanan c Kohesi Tanah Efektif ’

  Sudut Geser Dalam Tanah Efektif bi Lebar Irisan ke

• – i Wi Berat Iirisan Tanah ke
• – i i

  Sudut Yang Diasumsikan (didefinisikan) Dalam Ui Tekanan Air Pori Pada Irisan ke

• – i ru Nilai Banding Tekanan Pori u Tekanan Air Pori b Lebar Irisan γ

  Berat Volume Tanah h Tinggi Irisan Rata-Rata