LECTURE 2 : GENERAL PROPERTIES AND ROAD PROBLEM GENESIS AND GENERAL PROPERTIES GUDE CHAPTER 2

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MoU on Soft Soil Engineering1996 - 2001
Regional Teaching Program 2001 General properties
road problems G2 - V1 Republic of Indonesia
Kingdom of the Netherlands RT-02 July 9th -
2001
RWS/Grontmij/WitteveenBos
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUIDE
CHAPTER 2)
INTRODUCTION
TANAH GAMBUT

• TANAH GAMBUT ADALAH BAHAN YANG MEMPUNYAI
  KEMAMPUAN MAMPAT YANG TINGGI DENGAN KEKUATAN
  YANG SANGAT RENDAH.
• BAHANNYA MENGANDUNG SISA TUMBUHAN DENGAN
  BERBAGAI TINGKAT PEMBUSUKAN
• TEKSTUR DARI GAMBUT MULAI DARI YANG BERSERAT
  SAMPAI TIDAK BERBENTUK
• WARNA DARI COKLAT SAMPAI HITAM
• KADAR ORGANIK MERUPAKAN MATERIAL YANG POKOK DALAM
  PEMBENTUKAN GAMBUT.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUIDE
CHAPTER 2)
DEVELOPMENT OF TROPICAL PEAT DEPOSIT

• OCCURRENCE OF PEAT IN INDONESIA

PEAT LAND DI INDONESIA 18 - 27 JUTAHEKTAR
KALIMANTAN 50.4 IRIAN 24,9 SUMATERA 24,4
KADAR AIR 800- 1200 KETEBALAN 2 - 16 m
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

• ADANYA DAERAH GENANGAN AIR, DANAU, KOLAM (
  WETLAND)
• TARAF PERTAMA ( RHEOTROPIC) PEMASUKAN
  BAHAN-BAHAN KE DANAU ATAU DAERAH ALIRAN SUNGAI
• BERKEMBANGNYA TUMBUHAN EUTROPHIC SEPERTI
  ALANG- ALANG, RUSHES, SEDGES. SISA TUMBUHAN INI
  BERUBAH MENJADI GAMBUT (FEN PEAT)
• BERKEMBANGNYA FEN PEAT SAMPAI KE PERMUKAAN
  TANAH MAKA TERBENTUK GAMBUT TRANSISI
• BERKEMBANGNYA FEN DAN TRANSISI PEAT, TIMBUL
  PENDANGKALAN, AIR NAIK MENCAPAI PERMUKAAN,
  TERJADI KONDISI MESOTRAFIC, LALU BERKEMBANG
  TUMBUHAN DAN PEPOHONAN, KEMUDIAN DIMULAINYA
  TAHAPAN OMBROTROPHIC

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

• Gyttja TERBENTUK PADA TINGKAT AWAL PENDANGKALAN
  DANAU YANG DISEBABKAN OLEH ENDAPAN JASAD-JASAD
  TANAMAN AIR EUTROPHIC
• GAMBUT TRANSISI TUMBUH MELEBIHI MUKA AIR
  TANAH,
• LALU DITERAPKAN KONDISI MESOTROPIC (TINGKAT
  NUTRISI MASIH SEDANG ) VEGETASI BIASANYA TERDIRI
  DARI POHON
• BOG OMBROTROPHIC (DISKRIPSI DARI PEATLAND
  AREA, TUMBUHANYA TANANAMAN LUMPUR YANG HANYA
  TERGANTUNG KEPADA NUTRISI AIR HUJAN), MISKIN
  NUTRISI, KEASAMAN KUAT, DRAINASE TERTUTUP

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

• PEAT BOG TERBENTUK DENGAN DRAINASE TERTUTUP,
  KEBANYAKAN TERDIRI DARI SPHAGNUM, TETAPI JUGA
  ADA SEDGE, DAN POHON-POHONAN
• FEN SEPERTI PADANG RUMPUT YANG KAYA DENGAN
  SEDGE YANG BERADA PADA PEATLAND, KAYA NUTRISI,
  KEASAMANNYA KURANG BILA DIBANDINGKAN DENGAN
  BOG, BERDRAINASE. TUMBUHAN SPHAGNUM LEBIH
  SEDIKIT DARI
• CAMPYLIUM, SCORPIDIUM DAN DROPANOCLADUS SPECIES

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

1.ADANYA DAERAH GENANGAN
2. PEMASUKAN BAHAN-BAHAN
3. TUMBUHAN EUTRPHIC
4. GAMBUT BERKEMBANG SAMPAI PERMUKAAN
4.
5. TAHAPAN OMBROTROPHIC
FIG.2-2. THE WETLAND SUCCESSION
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

PADA BERBAGAI MACAM PEAT UMUMNYA KADAR SERAT
BERKURANG DENGAN MENINGKATNYA TINGKAT PEMBUSUKAN
FIG. 2.3. WATER CONTENT VERSUS DEGREE OF
DECOMPOSITION (1) BOG PEAT, (2)
TRANSITION PEAT, (3) FEN PEAT
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

FORMATION OF TROPICAL PEAT AREA
FIG. 2.4. TROPICAL PEAT FORMATION
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

TYPE DARI GAMBUT RAWA ADA 3 TYPE YANG
DIBEDAKAN TERHADAP LOKASI, KEDALAMAN DAN UMUR
BERDASARKAN RADIOCARBON DATING (1) COASTAL
PEATLAND (1-2 METRES ABOVE SEA LEVEL) (2) BASIN
OR RIVER VALLEY PEATLAND (5-20 METRES ABOVE SEA
LEVEL) (3) HIGH PEAT LAND (20-40 METRES ABOVE
SEA LEVEL)
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

FORMATION OF COASTAL MIRES IN INDONESIA

• The fluctuations and rise of the late Pleistocene
  sea level stabilised about 5000 years ago.
• During the following centuries, a rapid lateral
  deposition of coastal sediment took place which
  created extensive coastal tidal flats (or
  plains), notably in East Sumatera, Kalimantan and
  Southern Irian Jaya. Such flats were colonised by
  a mangrove plant community.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

FORMATION OF COASTAL MIRES IN INDONESIA

• The mangrove community stabilised the area so as
  to turn into more or less solid land making that
  in fact the coastline progressed into the shallow
  sea as the mangroves and lagoons under decreasing
  saline and increasing freshwater conditions
  became substituted by freshwater swamp forest and
  freshwater lakes, respectively.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• GENESIS OF PEAT

• The shallow freshwater lakes gradually filled up
  with organic matter produced by the lake
  vegetation (fen peat), developing into a swamp
  forest peat influenced by the groundwater peat.
  This form of peat formation is called a
  topogenous peat as the conditions of its
  formation were a high water table determined by
  topographic or geomorphological factors. Its
  composition is derived from a comparatively
  nutrient-rich plant community.
• On top of the topogenous peat, an ombrotrophic
  forest peat was formed.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• HUBUNGAN ANTARA BENTUK MORFOLOGI LUMPUR DAN
  SIFAT- SIFAT GAMBUT

• Hobbs indicates that properties of peat are the
  result of morphological processes. The following
  brings a number of these relations together.
• Due to the reinforcing effect of the fibres,
  stability is unlikely to be a problem on
  permeable, fibrous bog peats, whereas with works
  on highly humified, plastic, less permeable fen
  peats stability and rate of loading are foremost
  considerations.
• Fen peats formed by terrestrialization is
  commonly underlain by very soft organic muds
  which can cause severe engineering problem.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• HUBUNGAN ANTARA BENTUK MORFOLOGI LUMPUR DAN
  SIFAT- SIFAT GAMBUT

• Lake marls present an obstruction to probing and
  underlying bottom muds may go undetected,
  presenting a hazard to engineering works.
• Stratification in fen peats is likely to be more
  or less horizontal. Combined with the higher
  humification and thus lower permeability,
  vertical drains might have a useful application
  in accelerating primary settlement. Bog peats
  often have built-in vertical drains in the form
  of columnar cotton-grass tussocks, so that
  vertical drains might prove useless in bogs.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• HUBUNGAN ANTARA BENTUK MORFOLOGI LUMPUR DAN
  SIFAT- SIFAT GAMBUT

• Recurrence surfaces boundaries between highly
  decayed and well preserved moss peat, caused by
  climatic shifts impose a layered stratigraphy
  in contrast to the vertical characteristic
  produced by plan growth. Anisotropic hydraulic
  conditions result. One such recurrence surface
  Webers Grenz- horizont occurs quite generally,
  and will tend to act as a persistent horizontal
  aquiclude to vertical drainage and pore pressure
  relief under engineering works.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)

• HUBUNGAN ANTARA BENTUK MORFOLOGI LUMPUR DAN
  SIFAT- SIFAT GAMBUT

• Blanket bogs generally do not have a base of
  normally consolidated soft clay.
• Existing and potensial downhill movements of
  sloping mires by creep, sliding or flow (bog
  bursts) require special engineering measures.
• Knowledge of mire morphology is of importance in
  identifying floating mires, which if undetected,
  will obviously endanger construction works.

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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT

• AASHTO HANYA DISEBUTKAN KADAR ORGANIK TINGGI
• ASTM D-2487 LEBIH TERINCI KADAR ABU, KADAR
  SERAT, pH
• NEN TRIANGLE CLASSIFICATION

FIG.2.5. ORGANIC MATER-CLAY-SILT SAND TRIANGLE
ACCORDING TO NEN 5104
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
VON POST CLASSIFICATION
Table 2.4. Von Post Classification H1 Completely
undecomposed peat which releases almost clear
water. Plant remains easily identifiable. No
amorphous material present H2 Almost completely
undecomposed peat, which releases clear or
yellowwish water. Plant remains still easily
identifiable and no amorphous material
present.
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
VON POST CLASSIFICATION
H3 Very slightly decomposed peat which releases
muddy brown water, but for which no peat passes
between fingers. Plant remains still
identifiable and no amorphous material
present. H4 Slightly decomposed peat which
releases very muddy dark water. No peat is
passed between the fingers but the plant remains
are slightly pasty and have lost some of the
identifiable features.
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
VON POST CLASSIFICATION
H5 Moderately decomposed peat which releases very
muddy water with also a very small amount of
amorphous granular peat escaping between the
fingers. The structure of plant remains is
quite indistinct, although it is still
possible to recognize certain features. The
residue is strongly pasty. H6 Moderate strongly
decomposed peat with very indistinct plant
structure. When squeezed about one third of the
peat escapes between the fingers. The residue
is strongly pasty but shows the plant structure
more distinctly then before squeezing.
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
VON POST CLASSIFICATION
H7 Strongly decomposed peat. Contains a lot of
amorphous material and very dry indistinct
plant structure. When squeezed about one half
the peat escapes between the fingers. The
water, if any is released, is very dark and
almost peaty. H8 Very strongly decomposed peat
with a large quantity of amorphous material and
very dry indistinct plant structure. When
squeezed about two third of the peat escapes
between the fingers. A small quantity of plant
material remaining in the hand consists of
residues such as roots and fibres that resist
decomposition.
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
VON POST CLASSIFICATION
H9 Practically fully decomposed peat in which
there is hardly any recognizable plant
structure. When squeezed, almost all of the
peat escape between the fingers as fairly
uniform paste. H10 Completely decomposed peat
with no discernible plant structure. When
squeezed, all the wet peat escapes between the
fingers.
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
IDENTIFIKASI GEOTEKNIK DAN KLASSIFIKASI GAMBUT
VON POST CLASSIFICATION
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
INDEX PROPERTIES THE PLOT RELATIONSHIP FITS
WELL THE FOLLOWING FORMULA DERIVED FROM DUTCH
SOFT SOILS
? d(10 kN/m3) 0.872(w0.317)-0.982 2.1
Where ? d is dry density in kN/m3 w is the
moisture content in
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
INDEX PROPERTIES DRY DENSITY VS INITIAL WATER
CONTENT IN SOME INDONESIAN SOFT SOIL
FIG.2.6. DRY DENSITY VS INITIAL WATER CONTENT IN
SOME INDONESIAN SOFT SOIL
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
INDEX PROPERTIES DENSITY VS LOSS ON IGNITION
IN SOME INDONESIAN SOILS
FIG.2.7. DENSITY VS LOSS ON IGNITION IN
INDONESIAN SOILS
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
INDEX PROPERTIES SPECIFIC GRAVITY (Gs) AND
LOSS ON IGNITION (N)
IN BRITISH ORGANIC SOIL AND PEAT IS AS FOLLOWS
IN DUTCH ORGANIC SOIL AND PEAT IS AS FOLLOWS
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LECTURE 2 GENERAL PROPERTIES AND ROAD
PROBLEMGENESIS AND GENERAL PROPERTIES (GUDE
CHAPTER 2)
INDEX PROPERTIES SPECIFIC GRAVITY (Gs) AND
LOSS ON IGNITION (N)
IN INDONESIA SOILS
FIG. 2.8. SPECIFIG GRAVITY VS LOSS ON IGNITION IN
INDONESIA SOILS