TROPICAL WHEATHERING CLASSIFICATION

SUBJECT CODE BFC21303

SECTION 7

GROUP 1.MOHAMAD AL-AMIN BIN ZULKIFLI (AF180205)

MEMBERS
2.MOHAMAD ZAKI BIN KAMARUDDIN (AF180208)

3.MUHAMMAD AIMAN AL-HAKIM BIN MAT HUSSIN

(AF180183)

4.YASIN ABDIRAHMAN ELMI ( AF180001)

LECTURER PROF DR. AZIMAN

TABLE OF CONTENT
 CONTENT PAGE

1.0 INTRODUCTION 1-3

2.0 STUDY CASE 4-11

3.0 APPLICATION 12-20

4.0 CONCLUSION 21

5.0 REFERENCES 22
1.0 INTRODUCTION

Weathering is a term which describes the general process by which rocks are
broken down at the Earth’s surface into such things as sediments, clays, soils and
substances that are dissolved in water. The process of weathering typically begins
when the earth’s crust is uplifted by tectonic forces. After the physical breakup and
chemical decay of exposed rocks by weathering, the loosened rock fragments and
alterations products are carried away through the process of erosion. Erosion relies on
transporting agents such as wind, rivers, ice, snow and downward movement of
materials to carry weathered products away from the source area. As weathered
products are carried away, fresh rocks are exposed to further weathering. Over time,
that mountain or hill is gradually worn down.There are two types of weathering which
chemical and physical wheathering. Chemical Weathering results from chemical
reactions between minerals in rocks and external agents like air or water. Oxygen
oxidizes minerals to alteration products whereas water can convert minerals to clays
or dissolve minerals completely. Physical Weathering is when rocks are broken apart
by mechanical processes such as rock fracturing, freezing and thawing, or breakage
during transport by rivers or glaciers.

Physical weathering that is also called as mechanical weathering is the

disintegration of rock, mineral and soil aggregates by the mechanical or physical
processes acting mainly on pre-existing fractures such as cracks between mineral
grains and reduces the size of fragments according to the rock and structure of soil
without any change in the chemical composition of the rock or mineral. Abrasion is
the main process in the physical weathering process. Most of the time physical and
chemical weathering often goes hand in hand. However, physical weathering happens
because of pressure, temperature, frost and much more. The common examples of
physical weathering are cracks in the rocks that are exploited because of physical
weathering and increase the surface area exposed to chemical action and ultimately
amplify the rate of disintegration. Physical weathering remains happening in the
nature all the time. The common examples when water in a stream or river moves
speedily and can lift up rocks from the bottom of that body of water. At the end, when
rocks get to drop back down again, these collide with other rocks, and then tiny pieces

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of the rocks can break apart. The other name of physical weathering is disaggregation
or mechanical weathering.

Chemical weathering is one of the two types of weathering that tells about the
decomposition of rock, soil and other minerals by biochemical processes. It is a
biochemical process about weathering pits from where water collects and accentuates
rates of chemical weathering. In other words, it can be said as a process that deals
with the removal of chemical constituents from rock and results in the generation of
new minerals. It is an ongoing and gradual process just like mineralogy of the rocks
and minerals that adjust to the near surface environment. In the chemical weathering,
hydrolysis and oxidation are the most important processes. The process of chemical
weathering is enhanced by the multiple geological agents like oxygen and water and
also by the other biological agents like the acids that are generated by the plant-root
and microbial metabolism. The degree of chemical weathering differs from rock to
rock. For example, in the case of limestone, it occurs readily as compared to granite
where it takes some time. Various other factors are also involved in the chemical
weathering process. For example, the temperature is another factor that takes part an
important role and occurs more quickly in areas of high temperatures. Acid rain is one
of the major contributors to the process of chemical weathering when fossils fuels like
gas, coal, and gasoline are burnt they release carbon, oxides sulfur and nitrogen into
the atmosphere.

Both physical and chemical weathering work to break down and weaken
rocks, but the two processes work very differently. Unlike chemical weathering,
physical weathering doesn't change the chemical makeup of the rocks. Instead, it
includes processes that physically or mechanically break down rock. This may
include cracks caused by freezing and thawing cycles, breaks created by plant roots
that grow through the rock, or abrasion from blowing sand or rock particles.

Example of physical weathering, when water in a river or stream moves

quickly, it can lift up rocks from the bottom of that body of water. Second, when
the rocks drop back down they bump into other rocks, and tiny pieces of the rocks
can break apart. The next example is many rock surfaces have small crevices on
them. Fourth, water can freeze in these crevices when it is cold, and then melt when
the weather is warmer. This repeated freezing and thawing creates ice wedges,

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which can cause rocks to break. The last example physical weathering is thermal
stress weathering can occur in a desert climate that is hot during the day and cold
and night. The heating and cooling processes that happen every day put stress onto
rocks in the outer layer, causing the outer layers of the rock to start peeling off in
thin sheets.

Example of chemical weathering is hydrolysis. This process is just the

breaking apart of molecules by water molecules. This can happen when moving
water erodes rock to produce a saline (salty) solution. This can impact the ability of
aquatic organisms to survive in the environment in question.Second example is
hydration. This is the addition of hydrogen, a very abundant molecule thanks to the
abundance of water of Earth. When the mineral known as feldspar takes up
hydrogen, "expelling" other positively charged atoms in the process, the end
product is clay.

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2.0 CASE STUDY

This case study is Soils of the tropical forests of Leyte, Philippines. Site
qualities are in general a very complex aggregation of observable and measurable site
characteristics and which have to be evaluated for specific land uses (FAO, 1976).
With the aim of ecological land evaluation in mind, the large number of site
characteristics should be summarized in terms of possible rooting depth and
rootability as well as water, air, energy and nutrient budgets (Schlichting et aI., 1995).
Furthermore, statements about elasticity and stability of a site under a specific use are
needed in order to establish a sustainable land use. Since many site characteristics are
the result of pedogenesis, the development of qualities is therefore closely related to
the development of soils which in turn is time dependent. Land evaluation usually
accepts site characteristics more or less only as time dependent for the surveyable
period of a particular use. This is relatively short compared to the formation of soils.
Thus, in order to figure out the long term behavior of soils, it is the objective of this
paper to combine statements about soil formation with statements about site qualities
formation on a long time scale. The bigger part of the Island of Leyte (7955 km2) is
made up of volcanic rocks from different phases of volcanic activity during the
tertiary and quaternary age. The NNWSSE running central cordillera (max. height
1333 m) consists at the center of andesitic, basaltic and dacitic flows and breccia of
miocene age which are covered by younger lava flows (mostly of intermediate nature)
and deposits of volcanoclastics. Two research areas (see also part II by Asio et aI.,
this book, Fig. 1) were chosen at the western slope of the cordillera with hilly
landscapes about 12 km NE of Ormoc (700 m as!) and 8 km N of Baybay (100 m asl).

2.1 Material and method

The two soils, which are discussed here, have been chosen from a set of similar soils
(compare Asia et al. (part II), Fig. 2) identified in each area, being as representative of
more or less undisturbed conditions and maximum soil development in both areas.
Analyses of granulometry, porosity, bulk density, extractions with NH.-oxalate,
NaOH, Na-pyrophosphate and Na-dithionite-citrate and pH were carried out using the
methods of Schlichting et al. (1995). Ct was determined by the Walkley-Black
method (Nelson and Sommers, 1982), Nt by the Kjeldahl method (ISRIC, 1986),
cation exchange capacity (CEC) and exchangeable cations by the NH.- acetate

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method (Black, 1965), available P by Bray No.2 (PCARR, 1980) and P-retention by
the method of Blake more et al. (1981). Minerals were determined using a Siemens X-
ray equipment on powder- (sand and silt) and texture specimens (clay) and total
element contents were determined by X-ray fluorescence spectrometry. Soil forming
processes were quantified using the methods discussed by Barshad (1964), Alaily
(1984), Jahn (1988) and Schlichting et al. (1995).

2.2 Soil forming factors

Climate: The present climate is chracterized as a humid tropical monsoon climate

("tropical rainforest climate, monsoon type" after Koppen, 1923) with an annual
rainfall of about 3000 mm and an average annual air temperature of24,2 (Ormoc) and
27,4°C (Baybay). The rainfall distribution generally shows a more pronounced peak
rain period (up to nearly 500 mm per month) on the eastern side of the central
cordillera than on the western side. Only for a very short period does the precipitation
in the western side drop below 100 mm per month which corresponds to the average
monthly potential evapotranspiration. Typhoons regularly cross the Island during the
times of the SW-monsoon (June to October) and NW-monsoon (November to
February). The difference between the coldest and the warmest month is between 2
and 3°e. From these data (Barrera et al., 1954, VISCA-Meteorological Station) the
soil moisture regime can be classified to be udic and the soil temperature regime to be

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isohyperthermic.

Geology and Geomorphology: The site near Ormoc is situated in a hilly landscape
with volcanic cones which are rounded due to erosion. The remnants of the cones are
a clear indication of the quaternary age of the landscape. The parent material of the
investigated site is intermediate (55 % Si02) volcanoclastics, classified as local
trachytic basalt-andesite. The parent material of the Baybay site is more basic (50%
Si02) and is classified as porphyritic basalt. The generally very steep western slope of
Mt. Pangasugan, where the site is located, shows some plain areas at different heights
which are strongly dissected by rivers. This indicates that they were probably the
remnants of one or more old surfaces (peneplaines). The association of the strongly
eroded sites in the valleys and the deep weathered saprolites in the plains, is a further
argument for old (Pleistocene and/or Pliocene) erosion surfaces.

Vegetation: Both areas belongs to the natural rainforest type of dipterocarp forest.
The Ormoc site actually is at the edge of a residual forest which has a mixture of
shrubs and trees such as R. rosaefolius, L. capitellata, A. stipulaua, M. philippica and
some dipterocarps; herbs such as H. capita, E. tomentosus; grasses (S. spontaneum)
and some ferns. The Baybay site is located in a secondary forest which is presently
dominated by tree species like A. lebbeck, P. tinc-forium, A. blancoi, B. racemosa and
G. album. Many nontree plant species are also abundant in the area.

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2.3 Physical properties

Both pedons are low in rock fragments, but the Alisol shows considerable amounts of
saprolitized rock at a depth> 200 cm (Fig. 1), whose structure is easy to destroy by
hand. The texture in the two pedons is very different, being silty loam to sandy loam
in the Andosol, and heavy clay in the Aliso!. The measured low clay content of the
Andosol « 5%) is too low to be realistic and is in contradiction to the water content at
1500 kPa (25-32 %) and the CEC (17-38 cmol( + )/kg). The bulk density is generally
low for both pedons « 0.85 kg/dml), with the Andosol having the lowervalue (0.51
kg/dml) in the A-horizon and the Alisol (0.65 kg/dml) in the saprolite. As a result,
both pedons have high porosity of 69 to 77%.

2.4 Chemical properties

The pH (KC!) shows that the Alisol (pH 3,5-3.9) is more acidified than the Andosol
(pH 4.2-4.9). The pH mel\Sured in H20 gives smaller variations in the Andosol
compared to that measured in KC!. In the lower horizons of the Andosol, a
positive .:1pH occurs, indicating a positive net charge (Mekaru and Uehara, 1972). In
contrast to the differences in the particle size distribution, a relatively similar CEC can

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be observed in both pedons which decreases with depth from 38 to 17 cmol(+)/kg in
the Andosol but increases with depth from 27 to 39 cmol(+)/ kg in the Aliso!. The
base saturation is lower in the Andosol « 10%) than in the Alisol « 30%) and
decreases with depth in both pedons. The organic carbon stored in the first meter in
the Andosol is twice that of the Aliso!. As an indicator of the anion exchange
capacity, P-retention was measured. This gives absorption rates of > 96% in the
Andosol and 60 to 77% in the Alisol (100%= 5 g P/kg fine earth).

2.5 The weathering process

Early stages of weathering are indicated by the loss of bases and the turnover of Fe
from primary minerals (or volcanic glass) to secondary Fe-oxides. The intensity of
Fe-oxide formation seems to be nearly equal in both soils as the Fedlt ratio indicates
(Fig. 1). However, the amout of Fed in the Alisol (162 kg per m2, 404 cm depth) is
much higher than the Andosol (45 kg per m2, 160 cm depth). A qualitative difference
is given by the crystallinity of Fe-oxides, shown by the FeO/ d ratio (Blume and
Schwertmann, 1969), which for the whole pedon is 0.25 in the Andosol and 0.02 in
the Alisol (compare Tab. I). From the distribution of total element content in the
profile (Fig. 4), the large losses of Si, Ca, Mg, Na, K and P, the surplus of structural
water (ignition loss) and the residual increase of Al and Fe due to weathering of the
rock into soil, can be observed. Under the assumption of a homogeneous parent
material and relative stability of index elements, the changes in the other elements can

8
be calculated based on the ratio of each element to an index element in the rock and in
the soil. As index (stable) elements AI, Fe, Ti and Zr have been used, but the most
accurate results can be obtained by using Al (Fig. 4). The loss ofSi amounts to about
50% of its original content (Tab . 2). The %-Ioss in both pedons are in the same range
but the amount in the Alisol (0-404 cm) is two times higher than in the Andosol (0-
160 cm). This means, that the intensity of desilification is about equal in both pedons,
but the absolute amount is much greater in the Alisol. The loss of basic cations (Ca,
Mg, Na, K) from the original mass is about 90% in the Andosol and 97% in the
Alisol. This shows a more pronounced loss of basic cations than of silicon in the more
intensively weathered Alisol. The loss of Mn and P is clearly lower in the Andosol
than in the Alisol. The changes in the amounts of Fe (loss in the Andosol, surplus in
the Aliso!) are in the range of measurement errors (related to the homogenuity of
parent material) and should therefore not be interpreted. There is a large difference in
the amount of clay in the two pedons, it being 40 times higher in the Alisol than in the
Andosol (based on analyzed grain size distribution). Because of the already strong
desilification in the Andosol (molar AlISi ratio in the uppermost horizons 0.6 to 0.7,
in the lower horizons 0.9 to 1.3) it seems not possible for more imogolite to be formed
in the future . Therefore, it is estimated that further weathering favors the formation of
halloysite through lower leaching rates of Si (Parfitt and Wilson, 1985). This pathway
was obviously followed in the formation of the Alisol, too, as indicated by its high
amount of halloysite which in turn is now partly altered to kaolinite (higher in the
topsoil than in the subsoil). For a more complete kaolinitization of primarily formed
halloysite, it seems necessary to have land surfaces with a minimum age of 5 million
years, as shown by examples from the moist parts of the Canary Island. Indications
for this course of clay formation are given in pedons described by Caldas et aI. (1982)
and Salguero et al. (1985) for example. Thus, it is deduced from the Si-balance that
the large part of the halloysite in the Alisol was not formed via imogolite and/or
allophane.

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In conclusion The described soils can be seen as a chronosequence. The high degree
of desilification and loss of basic elements marks a final stage for the Andosol.
Desilification as well as loss of bases due to further soil development, will probably
not result in an increase in intensity but in an increase in the absolute amount (through
deep weathering). The pedogenic mineral association in the Andosol is of a greater
variety (ferrihydrite, goethite, imogolite, allophane, smectite/vermiculite, halloysite,
gibbsite) than in the Alisol (halloysite, kaolinite, goethite, hematite). The high amount
of halloysite in the Alisol is formed preferentially from preweathered material and not
necessarily from imogolite. The kaolinite is a product of the aging ofhalloysite.

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Gibbsite in the Andosol occurs as a feldspar-pseudomorphoses on locations with high
leaching rates. Both soils have excellent physical qualitites regarding rootability and
air and water supply to plants. The minimum factor for plant nutrition is given by the
very low amount of available P in both soils, aggravated further in the Andosol by
high P-retention. With the exception of K in the Alisol, both soils show reasonable
amounts of nutrient reserves with the Andosol having higher amounts than the Alisol.
Except for N, strong bonding forces are assumed for the nutrient reserve.

3.0 APPLICATION

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3.1 Climate Affect the Rate of Weathering in Tropica

Climate plays a definitive role in the breakdown of rocks into soils and
sediment, a process known as weathering. Rocks found in equatorial climates
and exposed to lots of rain, humidity and heat break down or weather faster
than similar rocks do when located in areas of the world with dry and cold
climates. A region’s climate plays a significant role in the rate of weathering.
The climate of tropical rainforests plays havoc with rocks, rapidly breaking
them into soils and sediment through repeated exposure to heat and copious
amounts of rainfall. A haboob a violent desert dust storm sandblasts rocks into
fine particles of sand, but not as fast as the rate of weathering that occurs in
tropical climates. Wet climates accelerate the rates of chemical weathering,
caused when C02 in dirt mixes with air and water to form a weak acid. The
weak acid breaks down rocks more rapidly in wet climates compared with dry
ones. The mineral olivine, for example, is relatively unstable and vulnerable to
chemical attack, so olivine-rich rocks break down much more rapidly in a
humid region. In general, hot wet climates accelerate chemical weathering
while cold dry climates accelerate physical weathering. Although the rate of
weathering depends on the type of rock, rocks in tropical climates experience
the highest rates of weathering because of the combination of high heat and
heavy rainfall.

3.2 Chemical, Physical and Biological Weathering

Weathering occurs one of three ways: through physical processes such as

freezing and thawing, because of live organisms whose roots break rocks or
through chemical processes that occur when carbon dioxide in the soil and air
and mixes with water and specific minerals in rocks to form a weak acid that
reduces rocks into silt, soil and sediment. Average temperatures, precipitation,
wind and sun over the course of a year define a region’s seasonal weather
patterns known as climate. Some types of rocks weather more rapidly in
humid climates, while dry climates make other rocks more susceptible to
attack. Limestone weathers rapidly in areas with wet climates, where rainwater
mixed with carbon dioxide in soil or creates a weak acid that dissolves the
limestone to form crevices and valleys. Sandstone, by contrast, weathers more

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rapidly in dry climates, because the quartz in the sandstone is largely
invulnerable to chemical weathering but can fall prey to fracturing caused by
ice formed when water freezes and expands in cracks in the stone.

1. Chemical weathering typically increases as

temperatures rise and rain falls, which means rocks in
hot and wet climates experience faster rates of chemical
weathering than do rocks in cold, dry climates. One type
of weathering, known as chemical weathering, works at
different rates depending on the chemical composition of
affected rocks. Two of the main chemical weathering
processes are oxidation and carbonation. Oxidation,
which is better known as rusting, weakens rock exposed
to air. The process produces red or brown discoloration,
as in weathered basalt. Rocks high in iron are most
susceptible to oxidation. Carbonation occurs when
carbon dioxide from the atmosphere mixes with water to
form weak carbonic acid. Carbonation chiefly effects
rocks high in calcite, such as limestone and marble.

Figure 5 show type of chemical weathering

2. Physical weathering occurs more often in cold

climates, because the different minerals within rocks
expand and contract at different rates when they are

13
 heated and cooled. Repeated heating and cooling cycles
eventually cause rocks to fracture. Desert and mountain
climates experience a wide range of temperatures from
low to high during a day and night, which accounts for
the breakdown of rocks known as physical weathering.

Figure 6 show the breakdown of rock due to weathering

3. Biological weathering occurs when living organisms

break up rocks. Tree roots, for example, can fracture
rocks in the same way they buckle pavement. Warm,
humid climates are most favorable to life. Contrast the
rich diversity of life in a rainforest, for example, with the
scarcity of life in the dry Sahara or the frigid Antarctic.
Consequently, rates of biological weathering are most
rapid in warm humid climates like those in tropical
regions.

figure 7 show the living organism breakup the rock

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3.3 Application of Tropical weathering classification in malaysia

The tropical climate such as Malaysia is known to produce the

unique weathering profiles and heterogeneous physical deterioration of
rock mass (Komoo 1995, Fookes 1997, Zainab 2004 ). The weathering
profiles differ with rock types. The large scale infrastructures
development such as North-South Highway, the Lebuhraya Pantai
Timur and Simpang Pulai – Ladang Blue Valley, Cameron Highland
had day lighted the complex geological features and their respective
geotechnical problems in sedimentary formation. The Kenny Hill rock
formation (KHF ) is a typical meta sedimentary rock formation,
consists of interbedded sandstone, siltstone and shale of Upper
Silurian-Devonian age. The low grade metamorphism of sandstone is
known as quartzite while shale is phyllite (Mohamed et al.2004). To
date, the geotechnical works in Kenny Hill formation has been much
simplified , due to lack of understanding of its engineering
characteristics . It is reported that many cut slopes from this formation
displayed the complex physical deterioration characteristics.

The key to an optimum engineering design of geotechnical

structure, its performance and stability in interbedded sedimentary
formation lays on the reliable characterisation and classification
methods, hence its respective results. The characterisation and
classification of rock mass by weathering grade requires a sound
knowledge on the principle of engineering characterisation and
classification of rock and soil. However, the conventional approach of
site investigation and characterisation techniques has failed to quantify
the in-situ engineering properties of sedimentary weak rock. As such,
most of structural design in Kenny Hill formation had been simplified
for example, a bore pile for foundation of massive structure and
instability of cut slopes despite a its high factor of safety.

A comprehensive and systematic geotechnical assessment has

15
been carried out on a typical cut slope of Kenny Hill formation in ,
Shah Alam Selangor. It has an example of typical interbedded rock
mass which is dominated by relatively thick sandstone and shale with
thin layer of siltstone varied from slightly to highly weathered
materials (Zainab 2004 ).This study only focussed on the sandstone
and shale that dominated a Kenny Hill rock mass, hence siltstone
properties shall be predicted. To quantify and model the physical
deterioration and mode of weathering of the interbedded sandstone and
shale were very tedious and complicated task as no one standard
method of testing was found to be suitable to measure the engineering
properties of both rock materials. However the standard guideline was
adopted for characterisation of these rocks so as the result obtained can
be systematically compared to previous researchers’ findings
(Mohamed et al.2001).

The principle of classification recommended that a simple index

test should be adopted for characterization and classification of rock
mass by weathering grade (Zainab 2004 ). The representative samples
of sandstone and shale dominating Kenny Hill formation has been
extracted base on locality for further geomechanical study in the
laboratory. Subsequently a comparative behaviour of these two rock
types was measured and discussed by assuming that they represent the
behaviour of a Kenny Hill rock formation.

16
 Figure 8. Slaking of shale (left) and intact sandstone (right).

Figure 9. Inclined bedding of shale and sandstone cut slope, showing

shale flakes covering sandstone underneath.

Boulder as the weathering product

Boulder (batu tongkol) is well known as one of the obstruction

material and problematic to the underground excavations and
constructions. Although the presence of boulder in weathered rock
mass was revealed and reported by many researchers, but the

17
occurrence and physical characteristics of boulders in weathering
profile are still not clearly understood. This paper attempts to revise the
issues and characteristics of boulder formed in weathered granite
which include the formation, distribution, properties and location of
boulders found in tropical weathering profile. As a weathering product,
boulder is dominantly found in moderately to completely weathered
zone of rock mass (Grade III to V). Boulder consists of corestone
Grade I or II and surrounded by some concentric sheet of weathered
rock Grade III to V or rindlets which formed due the reaction of
spheroidal weathering. The rindlets with thickness ranges 0.2 mm to
2.0 m is the zone of decomposition and dissolution of biotite and
feldspar that gradually transforming to saprolite. This information is
useful to geotechnical engineers and researchers for engineering
purposes and weathering zone classification especially in underground
excavation and structure design.

Table 1. Summaries the recommended system for classification of

weak rock by weathering grade for more than one rock types as a unit
rock mass ( after BS 5930 1999, Komoo & Mogana 1988, Santi &
Higgin 1998)

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 Figure 10: Corestone with five layers of rindlets, corestonerindlets
interface, rindlet zone, rindlet-saprolite interface

From engineer's point of view, the boulder is defined as an obstruction

material for underground excavations which possess various shapes of
spherical and size larger than 0.3 m and located at the unpredictable locations
in the weathering profile. As one of the weathering products, boulder can be
found embedded in sedimentary deposits glacial tills deposits , and at the

19
upper zone near the ground surface which commonly encountered during
tunneling, borehole drilling or underground excavation .The presence of
boulder in weathered rock mass can be seen from the excavated cliff, cut
slope, and soil excavation for underground construction.

4.0 CONCLUSION

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 A significant evident on physical deterioration had been produced by the
systematic characterization and classification research approach due to tropical
weathering. The physical properties of sandstone and shale are able to be
characterised and classified with respect weathering grade in a consistent field
and laboratory testing techniques and procedures. However, it was found that
the same testing method has resulted to a more reliable data. In order to get the
best result and measure the actual physical properties and behaviour in tropical
environment for specific engineering purposes, the characterisation and
classification of shale need a modified approach of testing.

The deterioration of sandstone and shale by weathering grade range from

rock-like state to soillike state, the study found. The mode of weathering of rock mass
was guided the comprehensive approach. The challenging task that engineers facing
was to quantify the physical changes of sandstone and shale due to tropical
weathering by the most practical manner because they need to produce a meaningful
and acceptable result.

In conclusion, these methods of engineering characterizations and

classification of sandstone and shale by weathering grade are the cheapest and the
most practical techniques for classification of weak sedimentary rock. There, it is
recommended to be adopted by geotechnical engineer in their site investigation work.

5.0 REFERENCE

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1.http://www.ejge.com/2007/Ppr0703/Ppr0703.htm

2.file:///C:/Users/user/Desktop/
MdDan2016CharacteristicsofBouldersFormedinTropicalWeatheredGraniteAReview.p
d

3.
https://images.search.yahoo.com/search/images;_ylt=Awr9IlNwB_Ne2ekAGh9XNyo
A;_ylu=X3oDMTE0anJjdTVqBGNvbG8DZ3ExBHBvcwMxBHZ0aWQDQTA2Mz
RfMQRzZWMDcGl2cw--?p=biological+weathering+definition&fr2=piv-
web&fr=mcafee#id=9&iurl=https%3A%2F%2Fcdn.britannica.com
%2F20%2F182520-004-498DCC8F.jpg&action=click

4. https://sciencing.com/weathering-erosions-activities-8268649.html

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