02- A PENYELIDIKAN TANAH - Widodo Sipil Ft-Ub · PDF fileTitle: 02- A PENYELIDIKAN TANAH...
Transcript of 02- A PENYELIDIKAN TANAH - Widodo Sipil Ft-Ub · PDF fileTitle: 02- A PENYELIDIKAN TANAH...
Penyelidikan Tanah
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Tanah?
Fungsi Pondasi…
Menerima beban dari bangunan atas (upper structures) , memikul, melimpahkan & meratakan
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melimpahkan & meratakan ke lapisan tanah di bawahnya.
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Dense SandDense SandDense SandDense Sand
Dense SandDense SandDense SandDense Sand
Soft ClaySoft ClaySoft ClaySoft Clay
Leaning Tower of Pisa
Kesalahan menjadi monumen!
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Limit States
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ServiceabilityServiceabilityServiceabilityServiceability UltimateUltimateUltimateUltimate
Foundation FailureFoundation Failure
ForceForceRotational FailureRotational Failure
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Soil HeaveSoil Heave ResistanceResistance
Kriteria Perencanaan(Design Criteria)
1. Daya dukung ijin ≥ tegangan yang terjadi atau angka keamanan terhadap keruntuhan geser cukup
2. Penurunan yang terjadi ( total and
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2. Penurunan yang terjadi ( total and differential settlement) masih dalam batas yang diijinkan
3. Aman terhadap pengaruh luar misalnya penggerusan, dll
Tujuan Penyelidikan Tanah
1. Menentukan jenis dan kedalaman pondasi2. Mengevaluasi beban - daya dukung pondasi3. Memperkirakan penurunan4. Menetukan potential problem misal : tanah
ekspansif, tanah mudah longsor, (collapsible
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ekspansif, tanah mudah longsor, (collapsible soil) dll.
5. Memperkirakan air tanah6. Memperkirakan tekanan tanah lateral misal :
untuk dinding penahan tanah7. Menentukan cara pelaksanaan ( construction
method )
Penyelidikan Tanah untuk Pondasi
Geo-Laboratory~ for testing
Design Office~ for design & analysis
soil properties
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construction site
Pengujian Tanah (Soil Testing)
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� CONE PENETRATION TEST (CPT / SONDIR)
� STANDARD PENETRATION TEST (SPT)
� PLATE BEARING TEST� FIELD VANE SHEAR TEST� DLL.
Sifat Tanah
1. Sifat fisik (physical properties)� Ukuran butir� Liquid limt & plastic limit ( batas atterberg)� Kadar air� Unit Weight ( γ ), Specific Gravity Gs
� Dll.2. Sifat mekanis (mechanical properties) � parameter kuat
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2. Sifat mekanis (mechanical properties) � parameter kuat geser c, φ.
� Unconfined compression test (uji kuat tekan bebas)� Direct shear test (uji geser langsung)� Triaxial compression test (uji tekan 3 sumbu)� Vane shear test
3. Sifat kemampatan (compressibility characteristics)� Uji konsolidasi (oedometer test)
4. Sifat hidrolis (hydraulics properties)� Uji permeabilitas (constant head & falling head)
Pengujian Tanah
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Pengujian sample tanah di Laboratorium
Pengujian Tanah
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Pengujian sample tanah di Laboratorium
SPT: Automatic Trip Hammer
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Field Drilling and Sampling
� Air or Mud Rotary Drilling
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Angle Drilling
� Assess geologic features (dip, strike, joints, etc.)
� Foundation testing for bridge abutments.
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bridge abutments.
Confined Access/ Interior Drilling
� Limited Access Drill Rigs are small in size, but have the torque of many full size truck
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many full size truck rigs.
� Capability, boring depths, size, etc. vary
� Esp. useful for remedial sampling
4Exploration for abutments, bridges, docks, etc.
Offshore Drilling/ Barge Rig
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docks, etc.
Drilling: Continuous Flight Auger
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� Casing with outer spiral� Inner rod with plug/or pilot
assembly� For sampling, remove pilot
Drilling & SamplingHollow Stem Auger
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� For sampling, remove pilot assembly and insert sampler
� Typically 5ft sections, keyed, box & pin connections
� Maximum depth 60-150ft
Drilling & SamplingHollow Stem Auger
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Boring Locations
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Profil Tanah
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KEDALAMAN BOR
LEBAR BANGUNANJUMLAH TINGKAT/LANTAI
1 2 4 8 16
(m)KEDALAMAN BOR
(m)
30,5 3,4 6,1 10,1 16,2 24,1
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61 3,7 6,7 12,5 20,7 32,9
122 3,7 7 13,7 24,7 41,5
UNTUK BANGUNAN RUMAH SAKIT DAN PERKANTORAN, SOWERS AND SOWERS (1970) MENGUSULKAN :
Db = 3 S0,7 UNTUK BANGUNAN BAJA RINGAN DAN BETON SEMPIT
Db = 6 S0,7 UNTUK BANGUNAN BAJA BERAT DAN BETON LEBARDIMANA :
Db = KEDALAMAN BOR ( m )S = JUMLAH TINGKAT/ LANTAI
JARAK LOBANG BOR
JENIS PROYEK JARAK (m)
BANGUNAN TINGKAT 10 - 30
BANGUNAN INDUSTRI 1 LANTAI 20 - 60
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BANGUNAN INDUSTRI 1 LANTAI 20 - 60
JALAN RAYA 250 - 500
PERUMAHAN 250 - 500
BENDUNGAN DAN TANGGUL 40 - 80
Kedalaman & Jarak Bor
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PROFIL TANAH
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Standard Penetration Test (SPT)
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Standard Split Spoon Sampler
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� Thick wall (0.25in) cylinder
� Sampling tube is split along the length
� Hammered into the ground
SPT Correction Factors
60.0
NCCCEN RSBm
60 =
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• hammer efficiency (Em) …. Table 4.3
• bore hole diameter (CB)…….Table 4.4.
• sampler correction (CS) ……Table 4.4
• rod length (CR) ………Table 4.4
Cone Penetrometer
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CPT Truck
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Crawler Type CPT Truck
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Typical CPT Data
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Texas Cone PenetrometerDesign Charts
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N KONSISTENSIKUAT TEKAN BEBAS
qu (kN/m2)
0-2 SANGAT LUNAK 0-25
Hubungan Konsistensi Lempung-Nilai SPT N
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2-5 LUNAK 25-50
5-10 SEDANG 50-100
10-20 KAKU (STIFF) 100-200
20-30 SANGAT KAKU 200-400
>30 KERAS (HARD) >400
Hubungan N - Kepadatan Relatif, - ΦTanah Pasir.
NKEPADATAN RELATIF
Φ(o)
Dr (%)
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0-5 0-5 26-30
5-10 5-30 28-35
10-30 30-60 35-42
30-50 60-95 38-46
Hubungan Nilai N - φφφφ
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Hubungan Penyelidikan Tanah-Biaya
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Laporan Penyelidikan Tanah
1. Skope penyelidikan2. Deskripsi rencana bangunan3. Deskripsi lokasi4. Keadaan geologi
Detail eksplorasi lapangan (jumlah,
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5. Detail eksplorasi lapangan (jumlah, kedalaman , jenis boring)
6. Deskripsi lapisan tanah7. Kondisi muka air tanah8. Rekomendasi pondasi9. Kesimpulan dan batasan penyelidikan
tanah.
Lampiran
� Peta lokasi� Denah lokasi boring� Boring log
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� Boring log� Hasil uji laboratorium� Grafik lain yang perlu
Rekomendasi Pondasi
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Denah Lobang Bor
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Profil Tanah
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Belajar
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Jangan tunggu sampai menit terakhir.
Exams
My mama always said, “Exam is like a box of chocolates; you never know what you
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of chocolates; you never know what you are gonna get”