DEPARTEMEN TEKNIK SIPIL DAN LINGKUNGANFAKULTAS TEKNOLOGI PERTANIAN
IPB
SIL211MEKANIKA TANAH, 3(2‐3)
Dr. Ir. Erizal, MAgr.
DESKRIPSIMempelajari definisi, sifat fisik dan
mekanis tanah, air di dalam tanah, tegangan tanah, kekuatan tanah, dayadukung tanah, pemadatan tanah, konsolidasi, dan Stabilitas tanah.
TUJUAN INSTRUKSIONAL UMUM
Mahasiswa dapat menjelaskan tentang sifat dan perilaku tanah, baik tanah sebagai bahan penahan pondasi maupun tanah sebagai bahan material dalam penerapannya untuk rancangan pondasi dan kaitannya dengan stabilitas tanah
KULIAH Pengajar: Dr. Ir. Erizal RB, M.Agr. (ERZ) dan Prof. Dr. Ir. Asep Sapei, MS.(ASP), danDr. Heriansyah Putra, SPd.,Meng (HSP)
No. Tanggal Pokok Bahasan Dosen
1. 6 Feb 18 Sifat‐sifat elemen tanah :1. Pendahuluan 2. Sejarah Perkembangan Mekanika Tanah3. Ruang Lingkup Mekanika Tanah
Erizal
2. 13 Feb 18
Sifat‐sifat umum tanah:1. Definisi teknis dari tanah dan Istilah yang digunakan2. Hubungan antara butir tanah, air dan udara dalam masa tanah (tanah 3 phase)3. Hubungan fungsiaonal elemen tanah 4. Batas‐batas kekentalan/konsistensi tanah5. Tegangan netral dan tegangan efektif tanah
Erizal
3. 20 Feb 18 Klasifikasi tanah:1. Pendahuluan 2. Sistem klasifikasi tanah 3. Karakteristik dasar tanah
Erizal
4. 27 Feb 18Stabilitas dan Pemadatan tanah:1. Pendahuluan 2. Stabilitas tanah (mekanis dan kimiawi)3. Macam‐macam stabilitas lapisan tanah dasar 4. Pemadatan tanah
Asep
5. 6 Mar 18
Hidrolika tanah:1. Air tanah 2. Air kapiler 3.Kondisi tekanan tanah dalam tanah4. Permeabilitas dan rembesan 5. Rembesan melalui beberapa lapisan endapan tanah6. Pengaruh gaya rembesan terhadap stabilitas tanah
Asep
6. 13 Mar 18
Hidrolika tanah:1. Faktor keamanan terhadap bahaya pengapungan (up lift)2. Piping dalam tanah karena aliran sekitar turap3. Rumus‐rumus dasar penngaliran tanah 4. Jaring‐jaring aliran (Flow Nets)
Asep
7. 20 Mar 18 Tegangan Efektif1. Pendahuluan 2.Tegangan Efektif pada Tanah Tak Jenuh3. Pengaruh gaya Rembesan pada Tegangan Efektif
Asep
UTS 27 Mar‐9 April 2018
No. Tanggal Pokok Bahasan Dosen
8 10 Apr 18Metoda Rasio Daya Dukung California:1. Pendahuluan 2. Definisi CBR 3. Percobaan CBR4. Jenis‐jenis CBR 5. Cara penaksiran dan penentuan nilai CBR
Erizal
9 17 Apr 18
Kekuatan Geser Tanah 1:1. Kriteria keruntuhan Mohr – Coulumb2. Penentuan parameter kekuatan geser tanah di laboratorium (uji geser langsung, uji
geser triaxial, uji geser uniaxial) 3. Uji kekuatan tanah di lapangan
Heri
10 24 Apr 18Kekuatan Geser Tanah (2):1. Kuat Geser Tanah Pasir 2. Kuat Geser Tanah Lempung
Heri
11 8 Mei 18
Kekuatan Geser Tanah (3):1. Kuat Geser Tanah Tak Jenuh 2.Sensitivitas Tanah Lempung3. Koefesien Tekanan Tanah Lateral Diam 4. Lintasan Tegangan
Heri
12 15 Mei 18
Konsolidasi tanah:1. Penurunan tanah 2. Teori konsolidasi 3. Test laborotorium konsolidasi 1 Dimensi4. Penentuan parameter konsolidasi tanah: indek kompresi, teg. prakonsolidasi, koef. kompresibilitas, koef. konsolidasi
5. Besar dan waktu penurunan (settlement) konsolidasi
Heri
13 22 Mei 18Penurunan Tanah1. Penurunan Segera 2. Penurunan Konsolidasi Primer
Heri
14 5 Juni 18
Kemantapan Lereng1. Pendahuluan2. Tipe kelongsoran lereng3. Metode Analisis Stabilitas Lereng
Erizal
UAS 25 Jun‐7 juli 2018
PRAKTIKUMNo. Praktikum:1. Indeks Properties2. Atterberg Limits3. Analisis Butiran (analisis saringan dan hidrometer)4. Test kerucut pasir5. Permeabilitas tanah6. Test Kompaksi7. Test CBR8. Test Geser Langsung9. Test Uniaxial10. Test Triaxial11. Pengukuran Kekuatan Tanah di lapang12. Test Konsolidasi
PENILAIAN UTS : 30 % Praktikum/Tugas : 30 % Ujian Akhir : 40 %
Kuliah : Selasa 7.30 – 9.10 WIB
Praktikum : Selasa 13.00 – 16.00 WIB (P2)
Jumat 13.30 – 16.30 WIB (P1)
Ruang Kuliah : RK V 02.1
PUSTAKA Bowles, J.E., 1986, Engineering Properties of Soils and Their
Measurements, McGraw Hill International Editions, New York Braja M.Das, Principles of Foundation Engineering, Wadsworth,
Inc., 1984 Braja M.Das, Principles of Geotechnical Engineering, PWS-Kents
Publishing Co., 1985 Craig, R.F., 1992, Soil Mechanics, Chapmann & Hall, London McKyes, E., 1989, Agricultural Engineering Soil Mechanics,
Elsevier, Amsterdam Rosenak, S., 1963, Soil Mechanics, B.T. Batsford LTD, London Ortigao, JAR., and Sayao, ASEJ., 2004, Handbook of Slope
Stabilisation, Springer.
Lecture Managemen System IPBhttp://lms.ipb.ac.id/
Pilih Civil and Environmental
Pilih SIL211 Mekanika Tanah
Laman LMS Mekanika Tanah
DEFENISI (Wikipedia) Soil mechanics is a discipline that applies principles of engineering
mechanics, e.g. kinematics, dynamics, fluid mechanics, and mechanics of material, to predict the mechanical behavior of soils. Together with rock mechanics, it is the basis for solving many engineering problems in civil engineering (geotechnical engineering), geophysical engineering and engineering geology. Some of the basic theories of soil mechanics are the basic description and classification of soil, effective stress, shear strength, consolidation, lateral earth pressure, bearing capacity, slope stability, and permeability. Foundations, embankments, retaining walls, earthworks and underground openings are all designed in part with theories from soil mechanics.
TANAH: Tanah adalah bagian kerak bumi yang tersusun dari mineral dan bahan organik. Lapisan tanah yang subur Tanah sangat vital peranannya bagi semua kehidupan di bumi karena tanah
mendukung kehidupan tumbuhan dengan menyediakan hara dan air sekaligus sebagai penopang akar. Struktur tanah yang berongga-rongga juga menjadi tempat yang baik bagi akar untuk bernafas dan tumbuh. Tanah juga menjadi habitat hidup berbagai mikroorganisme. Bagi sebagian besar hewan darat, tanah menjadi lahan untuk hidup dan bergerak.
Dari segi klimatologi, tanah memegang peranan penting sebagai penyimpan air dan menekan erosi, meskipun tanah sendiri juga dapat tererosi.
Komposisi tanah berbeda-beda pada satu lokasi dengan lokasi yang lain. Air dan udara merupakan bagian dari tanah.
THE LEANING TOWER OF PISA
GEOTECHNICAL ENGINEERING
Why Geotechnical Engineering?
“Virtually every structure is supported by soil or rock. Those that aren’t - either fly, float, or fall over.”
-Richard Handy, 1995
Case Study I: Building Foundation
Soft Clay Soil
20 ft of sand and gravel
15-ft soft fill and organic silt
Firm Soil or Bedrock
Weight of building (DL + LL) = 37,000 tons
Initial estimated settlement = 1 ft
Weight of excavated soil = 29,000 tons
Estimated settlement due to the net load of clay (37,000 – 29,000 = 8,000 tons) = 2-3 in.
75 ft
Source: Lambe & Whitman, 1969
Building 10 on M.I.T.’s Campus – Photo by Professor Zoghi, Sept. 1984
•How deep?
•Size of the footing (mat foundation)?
•Groundwater table?
•Dewatering?
•Braced excavation?
•Damage to adjacent buildings?
•Quantity and rate of the estimated settlement?
•Stress distribution?
•Design bearing capacity?
Design and Construction Issues
•Pile type?
•How deep?
•Spacing?
•Maximum allowable load?
•Pile efficiency?
•Driving/drilling?
•Optimum sequence of driving piles?
•How much variation from vertical?
•Adjacent buildings?
Alternative Foundations
Case Study II: Earth Dam
Source: Lambe & Whitman, 1969Zoned Earth Dam
Dimensions? (Most economical design)
Thickness of the rock facing and gravel to keep swelling of clay core to a tolerable amount?
The moisture content and compaction technique (lifts, equipment, etc) to place gravel and clay?
Permeability and seepage characteristics of the dam?
Consolidation and settlement characteristics of underlying soil?
Shearing strength parameters?
Potential leakage under and through the dam?
Factor of safety of upstream and downstream slopes?
Rapid draw down effect?
Seismic activity?
Design and Construction Issues
http://www.geol.ucsb.edu/~arthur/Teton%20Dam/welcome_dam.html
The Teton Dam, 44 miles northeast of Idaho Falls in southeastern Idaho, failed abruptly on June 5, 1976. It released nearly 300,000 acre feet of water, then flooded farmland and towns downstream with the eventual loss of 14 lives, directly or indirectly, and with a cost estimated to be nearly $1 billion.
Teton Dam Failure - Flood waters advancing through Rexburg, Idaho.
LandslidesIn excess of $1 billion in damages and 25 to 50 deaths each year in U.S.
Loss of SupportBridge Collapse – Kobe EQ
Annual Damage in the U.S.
Geo-Environmental
Municipal Solid Waste Approx. 3.6 lbs trash per
person per day Total trash = 216 million
tons Make up:
40% Cardboard18% yard waste9% metals8% plastic others
Landfills
Source: Coduto, 1999
How to Prepare?
Geotechnical Hall of Fame:http://www.ejge.com/People/HallFame.htm
Charles Augustin de Coulomb Grandfather of the Soil Mechanics
1736‐1806 (France) Friction and cohesion concepts
Lateral earth pressures on retaining walls
Structures, Hydraulics, Mathematics, Electricity, etc.
William John Maquorn Rankine 1820‐1872 (Scotland) Thermodynamics and soil mechanics
Lateral earth pressure theory
Pioneering role as an engineering educator
Karl von Terzaghi The Father of Soil Mechanics
1883 (Prague) – 1963 (Massachusetts)
Coined the phrase… First publication in 1925
Great many contributions
Arthur Casagrande 1902 – 1981Worked closely with Terzaghi
Started soil mechanics at Harvard
Received numerous awards
Fundamental soil mechanics problems…
Ralph Brazelton Peck 1912 – Winnipeg, Canada Co‐authored a textbook with Terzaghi
Initially a bridge designer…
Several decades as a pioneering foundation engineer and educator
Numerous awards
Alec Westley Skempton 1914‐2001 (UK) Established soil mechanics at Imperial College
Soil mechanics problems, rock mechanics, geology, and history of civil engineering
Nilmar Janbu 1920 ‐ NTNU – Norway Ph.D. student of Casagrande at Harvard
Slope stability problems – Janbu Method
Landslides in quick‐clay
Laurits Bjerrum 1918‐1973 The First Director of NGI (1951‐1973)
Quick clay Progressive failure of slopes
A “Giant”
Harry Bolten Seed 1922 – 1989 Father of Geotechnical Earthquake Engineering
UC Berkley Pioneering work in Geohazards
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