limestone in malasya

7/29/2019 Limestone in Malasya

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Environmental Geology of Limestone in Malaysia

TAN Boon-Kong

Geology Programme, Faculty of Science & Technology,

Universiti Kebangsaan Malaysia, Bangi, Malaysia

Abstract This paper provides an overview of the engineering geology of

limestone. Limestone is of rather wide occurrence in Malaysia. It is interesting in

view of the unique landforms and karstic features that are encountered in limestone

terrains, e.g. steep, subvertical limestone cliffs rising abruptly and majestically above

the ground surface and highly variable and pinnacled subterranean limestone bedrock.

The karstic features and associated engineering geological problems of both thelimestone hills and the bedrock are discussed in the paper. Rockfalls, sinkholes,

cavities, etc. are some of the common engineering geological problems associated

with limestone terrains. Some local case studies are provided as illustrations. Finally

the rock mechanical properties of limestone is discussed at the end of the paper. Key

words: engineering geology, limestone, Malaysia

1 Introduction

Limestone is a sedimentary rock consisting mainly of the mineral calcite (calcium

carbonate, CaCO3). The other common mineral in limestone is dolomite [CaMg

(CO3):]. Common impurities in limestone include chert (microcrystalline,

cryptocrystalline quartz or amorphous silica, SiO2), clay, organic matter and iron

oxides. Limestone is unique since it is soluble in even slightly acidic waters, such as

carbonic acid formed from the dissolution of carbon dioxide in water. The end results

of the solution of limestone are a host of karstic features, such as cavities, caves,

solution slots, pinnacled bedrock, stalactites/stalagmites, basal notches and overhangs

in limestone cliffs. In addition, residual soils left over in the dissolution of limestone

are so-called terra rossa or residual red clays mantling the limestone bedrock. These

are accumulations of the insoluble residues or impurities of the limestone, comprisingsilica, organic matter, clays, iron oxides, etc.

Limestone is metamorphosed into marble, i.e. a metamorphic rock consisting

predominantly of fine to coarse-grained recrystallised calcite and dolomite. Due to

recrystallisation, the crystals have interlocking or sutured boundaries forming a

mosaic, hence increasing the density and strength of the rock. Many of the

limestone formations in Malaysia have actually been metamorphosed into marble.

For example, the limestone formations in the Klang Valley (K.L. area) and the Kinta

Valley (Ipoh area) are strictly all marble. However, marble also shows the same

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solution features and behaviour as in limestone. This paper thus includes limestone

and marble, and for ease of presentation, they will be jointly referred to as limestone.

Limestone is of rather wide occurrence in Malaysia. In Peninsular Malaysia, the

major occurrences are in the Klang Valley, the Kinta Valley, Kedah-Perlis (including

the Langkawi Islands), Kelantan (Gua Musang area), and Pahang. In these

aforementioned areas, limestone occurs as majestic, precipitous cliffs as well as

extensive bedrock formations. No limestone hills occur in the southern regions of

Peninsular Malaysia (Johor, Melaka), and at one time it was thought that limestone

does not occur at all in the southern region of Peninsular Malaysia. However, in

recent site investigations, boreholes, mostly associated with various engineering

construction projects, have encountered limestone bedrock in some parts of Johor as

well as parts of Singapore Island. For example, the Tangkak vegetable farm area isunderlain by extensive limestone bedrock, as revealed by boreholes drilled for the

North-South Expressway in the Tangkak area. The Second Link Crossing joining

Johor to Singapore is also underlain by extensive limestone bedrock. Similarly, the

Tuas region and others in Singapore Island also have limestone bedrock.

Sabah and Sarawak have extensive limestone formations occurring in the forms of

numerous limestone hills and bedrock. The examples are the famous Mulu Caves and

the Niah Caves of Sarawak, which are of world fame in terms of cave formations and

exploration (speleology). They are also of geo-touristic value. The formations of

limestone hills and their associated cave systems have been the subject of numerous

studies. The interested reader is referred to Bulletin 6 by Wilford (1964) on the

geology of the Sarawak and Sabah caves. The memoir by Ingham and Bradford (1960)

also provides interesting reading on the geology of the limestone hills (including Gua

Tempurung) and bedrock in the Kinta Valley. Similarly, the memoir by Jones (1978)

discusses the limestone formations in Kedah-Perlis and the Langkawi Islands.

2 Limestone Hills

2.1 General karsttic features

Limestone hills are characteristically steep-sided, with subvertical to overhangingcliffs. The base of limestone hills also often exhibit deep horizontal notches or

undercuts due to dissolution by streams, groundwater or swamp water. Though they

might appear massive when viewed from the side, most limestone hills are actually

"riddled" with numerous caverns and cave systems. The interior of file limestone hill

mass may also be pock- marked with deep hollows or solution sinkholes or dolines,

locally called "wangs". These are visible from the ak or from aerial photographs, e.g.

Wang Pisang of Gunung Rapat, Ipoh. The famous cave systems include the Batu

Caves (K.L.), the Gua Tempurung and Sam Poh Tong in Ipoh, the Mulu and Niah

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Caves in Sarawak, etc.

Limestone hills are of all sizes and heights. They are actually the remnants of the

limestone formation which has been degraded/dissolved, and the collapse of the

limestone cliffs contributes to the reduction in the size of the limestone hills. In a

previous survey of the limestone hills in the Kinta Valley, for example, some 40

limestone hills of various sizes have been recorded (Tan, 1988). While some

limestone hills are "massive" and spatially extensive, e.g.G. Rapat, G. Tempuruing -

G. Rajah massif, others appear as slender, needle-like limestone hill pinnacles, the

notable example being the so-called Tambun Tower (Tan, 1998a).

Intersecting or criss-crossing the limestone hills are various geologic structures or

fractures such as joints and faults, and together with the intrinsic bedding planes of

the limestone, these geologic structures control the stability of the cliffs, theformations and orientations of caves and cave systems and other dissolution features.

2.2 Rockfalls

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Rockfalls and rockslides are major engineering geologic problems associated

with limestone hills. The steep-subvertical and often overhanging limestone cliffs are

potentially hazardous in terms of rock slope stability, and numerous major incidences

of rockfalls have been investigated and documented by the Geological Survey

Department in the past (e.g. Shu et al., 1981; Shu and Lai, 1980). In the survey of

limestone hills in the Kinta Valley area, numerous minor occurrences of rockfalls and

potential rockfall sites were also documented by me (Tan, 1988), in addition to the

major ones previously documented by the Geosurvey. Besides structural control by

joints, faults and bedding planes, other significant contributing factors to rockfalls

include blasting operations in nearby quarries (vibrations and gas expansions into

fracture planes).

2.3 Rockfall hazards zonation--the Tambun Hills

An investigation into the potential rockfall hazards in the limestone hills of the

Tambun area has been conducted recently (Tan, 1998b). The objectives of the study

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were to identify and categorise the various limestone cliffs into various hazards zones,

so as to aid in the planning of development and construction around these hitlls. The

methodology adopted involved ranking the various cliff faces in terms of stability by

considering both the geological structures and the solution features. A 3-zone

classification scheme was used to denote stable/low hazard, moderately

stable/moderate hazard, and unstable/high hazard zones, producing a hazard zonation

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map for planning purposes. Some typical results of the study are shown in Table 1

and Fig. 1.Details can also be referred to in Tan (1998b).

Among other things, one of the conclusions of the study was that the

north-south-trending bedding planes of the limestone hills in the Tambun area are the

major structural features controlling the morphology and the stability of the cliff faces.

The so-called Tambun Tower is one good example.

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3 Limestone Bedrock

Limestone bedrock is perhaps even more important from the view-point of

engineering constructions such as buildings and roads. The various bedrock features

affect the construction works directly; they can also affect structures sited in

limestone terrains in the future (long term effects) many years after the completion of

the project.

3.1 Pinnacled bedrock surface

The highly variable and pinnacled limestone bedrock surface and its associated

problems are now well known and well documented (e.g. Tan and Batchelor, 1981;

Ting, 1985; Chan, 1986; Tan, 1987). Exposures in old mine pits provide the bestopportunity to observe the myriad forms of limestone pinnacles and troughs. The

Bandar Sunway/Sunway Lagoon area exhibits some classic examples of limestone

pinnacles, arches, etc.

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It is interesting to note the generally deep depths to limestone bedrock in the Kuala

Lumpur area as compared to those in the Ipoh area, as revealed by a study of borehole

data in the two regions (Fig.2, Tan, 1993). Depths to bedrock are around 20 m in the

Ipoh area, as compared to 30-50 m in the K.L. region. Overhangs in the limestone

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pinnacles would be harder to detect as it involves coring through the "nose" of the

overhang. They are critical since the overhangs are underlain by soft sediments or

soils. Mitchell (1985) provides a good example of the limestone pinnacle overhang at

the Pan Pacific Hotel site in K.L.

3.2 Linear trenches in bedrock

Long, linear trenches can sometimes be observed traversing limestone bedrock

surfaces. Such trenches are the results of dissolution of limestone along major joints

or faults. The interesting thing about the long, linear trenches is that they are often the

sites of numerous sinkholes "popping up" along the trenches. To look at it in

another way, the localities of several sinkholes in an area are often aligned along

definite lines corresponding to the trends of major joints or faults dissecting thebedrock. Once again, exposures in old or operating mine pits or bedrock quarries

provide the best opportunity to view these long, linear trenches. As the widths of the

trenches are often limited, say, a couple of metres only, the sinkholes appearing along

the trenches thus have small diameters of a couple of metres only -- a common

observation with regard to the diameters of sinkholes. At the intersection of two

trenches, however, the sinkholes that develop would be of larger diameter than usual,

say 5-10 m.

3.3 Cavities in limestone bedrock

Cavities in the limestone bedrock are of major concern to foundation engineers.

They occur at various depths, i.e. in multi-levels, and are of various sizes/thicknesses.

A survey of cavity sizes based on borehole data in the Ipoh area showed that they are

mostly < 3 m in thickness (Table 2, Tan, 1988). Ting (1985) and Ting et al. (1993)

also concluded that the most common cavity size is < 1m. In any case, occasional

large cavities >3 m can still be encountered at a particular site.

Thus, the detection and determination of the detailed configuration of the cavities

and cavity system at a particular construction site are major efforts in a site

investigation programme, in particular where high-rise buildings are being planned

and constructed. Three dimensional physical models have been used to depict anddecipher the intricate nature and extent of the cavities and the bedrock profile.

A recent high-rise project in the K.L. area witnessed the tremendous efforts put in

to detect the cavities in the limestone bedrock by employing > 100 boreholes on a

close-grid boring pattern. Numerous cavities, some at multi-levels, were detected

through those efforts. The number of boreholes for high-rise buildings underlain by

limestone bedrock are in the order of 100's, e.g. the Petronas Twin Towers have ~400

deep boreholes (Tarique Azam, 1996).

The formation of cavities in the limestone bedrock is related to the fluctuations of

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the groundwater level. Cavities are developed mostly within the zone of groundwater

level fluctuation, and it is reasonable to expect that deeper down below the zone of

active groundwater fluctuation, cavity formation would be limited. The exposures at

the Bandar Sunway Quarry (bedrock) seem to support such an idea that below a

certain depth the limestone bedrock is massive (although jointed) without cavities or

other solution features. Nearer the surface, large cavities, solution arches, pinnacles

etc. are observed.

For the K.L. region, it would be reasonable to postulate that below a certain

Reduced Level (RiL), the limestone bedrock would not contain any cavities. The

determination of this R.L. would require a meticulous compilation of all borehole

data in limestone in the K.L. region--something that has not been attempted to date!

Fig. 3 illustrates the development of cavities/caves in relation to limestone hills assuggested by Wilford (1964), which is perhaps also applicable to limestone bedrock.

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3.4 Slumped zone

One of the unique features of the limestone bedrock terrain is the occurrence of

the so-called slumped zone or collapsed weak soil zone immediately above the

limestone bedrock surface. The formation and identification of this slumped zone

has been discussed by Tan and Ch'ng (1986). It has been encountered in numerous

high-rise building sites in K.L. since the early 1980's (e.g. Chan and Hon, 1985; Ting,

1985), and also recently at the K.L.C.C. Petronas Twin Towers site (Tarique Azam,

1996).

Recognition of the presence of the slumped zone is via its very low S.P.T. N

values of ~0 as limestone bedrock surface is approached. Overlying the slumped zone

can be much stiffer soils with N=30-50 or more, such as the residual soils of the

Kenny Hill formation in the K.L. area. Fig. 4 shows some typical examples. In theK.L. area, the slumped zone often occurs close to the Kenny Hill

formation--Limestone contact zones.

Similar occurrences have been reported in other limestone areas, e.g. Ipoh (Tan,

1988) and Hong Kong (Pascal, 1987).

3.5 Sinkholes

Sinkholes are the main crux of the problem in a limestone bedrock terrain.

The formation or emergence of a sinkhole is usually very sudden and unpredictable,

and as such, its consequences can be catastrophic. Thus, the reporting and

documentation of sinkholes swallowing parts of a road, a house, etc. are too common

indeed. While the inherent karstic features of the limestone bedrock (such as

pinnacled profiles, cavities and linear trenches) all contribute or provide the geologic

settings for the development of sinkholes, other man-made factors or activities

such as dewatering of groundwater level by pumping, dewatering of deep

excavations or basements and open-cast mining can trigger the formation

or emergence of sinkholes. The documented cases of sinkholes in the Kinta and

Klang valleys include the Bt. Merah/Menglembu area in Ipoh (Shu, 1982, 1986;

Chow et al.,1996), Serdang Lama in K.L. (Shu, 1986) etc. The emergence of

sinkholes in the Bt. Merah area continues till today (1999), as reported frequently inthe local press. Similarly, in the recent construction of the K.L.C. C. Petronas Twin

Towers project, several sinkholes also "popped up", including a major one that

damaged a nearby bungalow.

An interesting study on the occurrences of sinkholes (>100 in number) in the

Bau area, Kuching Division in Sarawak was conducted in 1993-1994. Unfortunately,

the results of the study cannot be presented here for the time being

(CONFIDENTIAL!) --perhaps some time in the near future, hopefully?

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For the interested reader and also as a reminder that sinkholes occur world-widein limestone areas, the following references provide interesting readings: Beck (1984),

Beck and William (1987) and Beck (1989). For example, the famous Winter Park

sinkhole in central Florida which developed between May 8-13, 1981, had an initial

diameter of -106 m and a depth of 30 m! It destroyed various facilities and utilities,

including a house, several businesses, several cars and a swimming pool and caused

major problems for the city of Winter Park (Jammal, 1984). Fortunately, no personal

injuries were involved.

Various "schematic models" have been presented by different authors to explain

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the formation of sinkholes. Some of these schematics are shown in Figs. 5 and 6,

cited from Taylor et al. (1989) and Chen and Beck (1989) respectively.

4 Rock Mechanical Properties

Some rock mechanical properties based on testing of limestone rock cores in the

laboratory are given in Table 3, cited from Tan and Ch'ng (1987). Additional data are

given in Table 4, cited from Raj (1994).

5 Conclusions

This paper provides an overview of the engineering geology of limestone.The karstic features and engineering geologic problems associated with

limestone, both limestone hills and bedrock, are now well known. For the case of the

limestone bedrock, the need for adequate S.I. (including number of boreholes) cannot

be over-emphasised to define and map out accurately the myriad forms of solution

features inherent in the limestone bedrock.

References

Beck, B.F. (ed.), 1984. Sinkholes: geology, engineering and environmental impact. In: Proc.

1st Multidisciplinary Conference on Sinkholes, Orlando, Florida, 15-17 Oct., 1984, 429 pp.

Beck, B.F. (ed.), 1989. Engineering and environmental impacts of sinkholes and karst. In: Proc.

3rd Multidisciplinary Conference on Sinkholes and the Engineering & Environmental Impacts

of karst, St. Petersburg Beach, Florida, 24 Oct., 1989, 384 pp.

Beck, B.F., and William, W.L. (eds.), 1987. Karst hydrogeology: Engineering and environmental

applications. In: Proc. 2nd Multidisciplinary Conference, Orlando, Florida, 9-11 Feb, 1987, 475

pp.

Chan, S.F. ((ed.), 1986. Foundation problems in limestone areas of Peninsular Malaysia. Geotech.

Engineering Div., IEM, Sept. 1986, 98pp.

Chan, S.F., and Hon, L.P., 1985. Pile foundations in limestone areas of Malaysia. In: Proc. 8th S.E.

Asian Geotech. Conf., K.L. March 11-15, 1985, 4-17 to 4-28.Chow, W.S., Jamaludin Othman and Loganathan, P., 1996. Geotechnical problems in limestone

terrain with emphasis on cavities and sinkholes. In: Proc. Seminar Geologi Dan Sekitaran, 6~

Dec., 1996, UKM, Bangi, 102-117.

Jammal, S.E., 1984. Maturation of the Winter Park sinkhole. In: Beck, B.F. (ed.), Proc. of the 1st

Multidisciplinary Conference on Sinkholes, Orlando, Florida, 15-17 Oct., 1984, 363-369.

Mitchell, J.M. (1985). Foundations for the Pan Pacific Hotel on pinnacled and cavernous

limestone. In: Proc. 8th S.E. Asian Geotech. Conf., March 11-15, 1985, 4-29 to 4 44.

Pascal, D., 1987. Cavernous ground in Yuen Long, Hongkong. Geotechnical Engineering, 18 (2):

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205-221.

Shu, Y.K., 1982. A sinkhole occurrence in Bt. Merah New Village, Menglembu, Ipoh. Jabatan

Penyiasatan Kajibumi Malaysia, Laporan E(F) 1/1982.

Shu, Y.K., 1986. Investigations on land subsidence and sinkhole occurrence in the Klang Valley

and Kinta Valley in Peninsular Malaysia. In: Proc. LANDPLAN H Conf., K.L., 15-28.

Shu, Y.K., and Lai, K.H., 1980. Rockfall at Gunung Cheroh, Ipoh. Geological Survey Malaysia,

Geological Papers, 3: 1-9.

Shu, Y.K., Chow, W.S., and M. Zakaria, 1981. Rockfall danger related to limestone hills in the

Kinta Valley, Perak. In: Annual Report, Geological Survey Malaysia, 1981, 184-197.

Tan, B.K., 1987. Geology and urban development of Kuala Lumpur, Malaysia. In: Proc.

LANDPLAN 1II Symposium, 15-20 Dec., 1986, Hongkong, 127-140. (published as Geological

Society of Hongkong Bulletin No.3, Oct. 1987).Tan, B.K.,1988. Geologi kejuruteraan kawasan sekitaran Ipoh, Perak. (Engineering geology of the

Ipoh area, Perak). Laporan Akhir Projek Penyelidikan No.7/86, Sept. 1988, UKM, 74 pp.

Tan, B.K., 1990. Subsurface geology of Ipoh area, Perak, Malaysia. In: Proc. Conf. on "Karst

Geology in Hongkong",5-7Jan. 1990, Hongkong, 155-166. (published as Geological Society of

Hongkong Bulletin no. 4, 1990).

Tan, B.K., 1993. Urban geology of Ipoh and Kuala Lumpur. In: Proc. Forum on Urban

Geology and Geotechnical Engineering in Construction, IEM-GSM, July is~, 1993, Petaling

Jaya, 1-1 to 1-25.

Tan, B.K., 1998a. The Tambun Tower--a photographic presentation. Newsletter, Geological

Society of Malaysia, 24(3): 133-134.

Tan, B.K., 1998b. Engineering geological survey of limestone cliffs in the Tambun area, Perak,

Malaysia. In: Proc. 8th IAEG Congress, Vancouver. Sept. 21-25, 1998, Vol. H, 1359-1366.

Tan, B.K. and Batchelor, B., 1981. Foundation problems in limestone areas--a case study in

Kuala Lumpur, Malaysia. In: Proc. Int. Syrup. On Weak Rocks, ISRM, 21-24 Sept., 1981,Tokyo,

1461-1463.

Tarique Azam, 1996. Project KLCC: Geology, soils and foundations. Newsletter, Geol. Soc.

Malaysia, .22 (2): 73-74.

Ting, W.H., 1985. Foundation in limestone areas of Malaysia. In.Special Lecture, Proc. 8th S.E.

Asian Geotech. Conf., Kuala Lumpur, Vol. 11, 124-136.Ting, W.H. (ed.), (undated). Engineering and geology in the Kuala Lumpur area. ESCAP

publication.

Ting, W.H., Lau L.Y., and Chen, M.S., 1993. Treatment of cavities for piled foundations. In:

Proc. Forum on Urban Geology and Geotechnical Engineering in Construction, IEMGSM, July

1st, 1993, Petaling Jaya, 2-1 to 2-14.

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limestone in malasya

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