Investigation of Completely Decomposed Weathered Granitic Soil in Peninsular Malaysia

Investigation of Completely Decomposed Weathered Granitic Soil in Peninsular Malaysia

Introduction: Granite

• Granite is a common and widely occurring type of intrusive, igneous rock.

• The most essential mineral constituents or granite are:– quartz– feldspar– accessory minerals (muscovite, biotite and etc.)

Figure 4: Granite containing potassium feldspar, plagioclase feldspar, quartz, biotite and/or amphibole. The pictures are close-up of granite taken from Yosemite National Park, USA.

RESIDUAL GRANITIC SOIL IN PENISULAR MALAYSIA

• More than 75% of the land mass in peninsular is comprised of residual granitic soil

• Peninsular Malaysia is separated by a long, mountain range that started from Malacca to the northern area of Perak.

• Since granites are the main components of this mountainous range, granitic residual soil will form upon undergoing a weathering process.

Introduction Of Properties Of Completely Decomposed Weathered Granite

Weathering processes occur depends mainly on the following three factors:

• Environmental;• The properties of rock mass;• The properties of the rock material.

Typical weathering profile: residual soils

Table 2: Weathering classification system for granite and volcanic rocks (Hencher and Martin, 1982)

Geological map Of Peninsular Malaysia

Selected site for Investigation in Penang island

Selected site for Investigation in Kuala Lumpur

Location: Seremban Test: Compressive strength test

Location: Seremban• Modulus of elasticity Depth Vs Compressive strength

Consolidated Drained Consolidated Undrained

Location: Kuala LumpurTest: Triaxial test

Results of consolidated drained triaxial test on undisturbed sample:(a) Deviator stress vs. axial strain (b) Volumetric strain vs. axial strain

Results of consolidated drained triaxial tests on undisturbed sample: (a) Deviator stress vs. axial strain (b) Pore pressure vs. axial strain

Location: Kuala LumpurTest: Triaxial test

Consolidated Drained Consolidated Undrained

Mohr's stress circles at failure and failure envelop for CD test

Mohr's stress circles at failure and failure envelope for CU test

Location: KM 31 along the Kuala Lumpur-Karak highway.Test: Infiltration test

Reference: infiltration characteristic of residual soils, Jurnal Teknologi, 42(B) Jun. 2005: 45–56 © Universiti Teknologi Malaysia

Location: KM 31 along the Kuala Lumpur-Karak highway.Test: Infiltration test

Field infiltration test using Geonor infiltrometer

Reference: infiltration characteristic of residual soils, Jurnal Teknologi, 42(B) Jun. 2005: 45–56 © Universiti Teknologi Malaysia

Result

Reference: infiltration characteristic of residual soils, Jurnal Teknologi, 42(B) Jun. 2005: 45–56 © Universiti Teknologi Malaysia

Properties Kuala Lumpur[3] Penang[1] Seremban [4]

Specific gravity,Gs

2.63 1.68 2.55

Moisture content (%),w

- 25 -

Dry density (kN/m3),d

1.61 1.68 13.6

Void ratio 0.63 - -Porosity 0.39 - -Clay content (%) 17.3 12 42Silt content (%) 257 23 23Sand content (%)

51.7 38 35

Gravel content (%)

5.7 28 0

Comparison

Case Study

Highland TowersHulu Kelang, Ampang

Kuala Lumpur

Highland Towers Condominium

Investigation Scope

• To carry out geotechnical evaluation of the foundation system used, ground condition of the site and the surrounding areas

• Examination relies only on extensive site excavation and measurements

Investigation Scope

• Leaded by Mr. Azman bin Abdul Samad, Institut Kerja Raya Malaysia (IKRAM)

• Result has been reviewed several times by experts from the investigation teams and independent specialists

• Complete report on the soil investigation is in Volume 2 and 3

Investigations (al, 1994)

Investigation Purpose Carried by

Petrographic Study Rock TypeGeological Department of University Malaya

Geological MappingExtent of rock type and fractured zone

Geological Survey Department

Boreholes Soil ProfileInstitut Kerja Raya Malaysia (IKRAM)

Soil Classification Soil grouping IKRAM

Mineralogy Analysis Soil mineral IKRAM

Shear Box Soil Shear Strength IKRAM

Surface Infiltration Permeability IKRAM

Borehole Permeability Permeability IKRAM

Field Density Soil weight IKRAM

Investigation Result

• Petrographic Study– Sheared and fractured muscovite adamellite– Banded greisenized fractured adamellite– Sericitized fractured pegmatite

• Soil Classification– Medium dense to dense residual granitic soil

4 to14 m

3 to 12 m

Properties of soil

• Mineralogy Analysis– Most abundant mineral was Quartz– Active clay mineral: Kaolinite

• “Active” Clay Mineral– 15.3% to 37.4%

• Kaolinite: 10.5% to 21.1%

Properties of soil

• Shear Box – Undrained shear strength, c’= 4.0 to 6.0 kPa– Undrained friction angle, ф’= 33° to 41°

• Field Density– Conducted in three trial pit locations– Average total unit weight: 19kN/cm3

Discussion

Comparison of properties:Penang - Kuala Lumpur - Seremban

Specific Gravity

• Contains different percentage of minerals– density of silica is 2.65– density of iron is 7.87

• Contains different type of soil– organic soil– peat soil– sand

Kuala Lumpur Penang Seremban

2.63 1.68 2.55

Water Content

• Infiltration of precipitation– increase surface run-off = less water content

• Condition of the terrain– steep slope = less water content– flat ground = more water content

Kuala Lumpur Penang Seremban

0.31 or 31% 0.25 or 25% -

Dry Density

• Specific gravity– high GS, high dry density

• Air void– low A, high dry density

• Water content– low W, high dry density

Kuala Lumpur Penang Seremban

13.6 kN/ m3 1.68 kN/m3 16.7 kN/m3

Void Ratio and Porosity

• Kuala Lumpur ~ 0.63 and 0.39

• e = n / 1 – n

– low porosity, low void ratio

• High soil density, low void ratio

– Assumption: Penang soil specimen void ratio

should be higher than Kuala Lumpur

Conclusion

• Research materials:– Online journals– Report Of The Inquiry Committee Into The Collapse

Of Highland Towers, 1994• still difficult to draw a simple conclusion to

describe the common behavior of granitic soil throughout peninsular Malaysia

• most of the landmass in Peninsular Malaysia– residual granitic soil (from Banjaran Titiwangsa)

© 2010 CEGB 333| Investigation of Completely Decomposed Weathered Granitic Soil in Peninsular Malaysia