Laterite Soil Collapse Potential

Seediscussions,stats,andauthorprofilesforthispublicationat:http://www.researchgate.net/publication/261722181

Collapse/SwellPotentialofResidualLateriteSoilDuetoWettingandDrying-wettingCyclesARTICLEinNATIONALACADEMYSCIENCELETTERSAPRIL2014ImpactFactor:0.24DOI:10.1007/s40009-013-0221-4

DOWNLOADS14

VIEWS116

5AUTHORS,INCLUDING:

MehrdadKholghifardUniversitiTeknologiMalaysia10PUBLICATIONS7CITATIONS

SEEPROFILE

N.AliUniversitiTeknologiMalaysia32PUBLICATIONS40CITATIONS

SEEPROFILE

AzmanKassimUniversitiTeknologiMalaysia17PUBLICATIONS23CITATIONS

SEEPROFILE

RoohollahKalatehjariNationalChungChengUniversity33PUBLICATIONS25CITATIONS

SEEPROFILE

Availablefrom:RoohollahKalatehjariRetrievedon:21September2015

RESEARCH ARTICLE

Collapse/Swell Potential of Residual Laterite Soil Dueto Wetting and Drying-wetting Cycles

Mehrdad Kholghifard Kamarudin Ahmad

Nazri Ali Azman Kassim Roohollah Kalatehjari

Received: 19 December 2012 / Revised: 4 October 2013 / Accepted: 31 December 2013 / Published online: 8 March 2014

The National Academy of Sciences, India 2014

Abstract Lack of consideration in the soil behaviors

related to drying and wetting phenomenon namely volume

change and collapsibility may cause damages to founda-

tions, buildings, and other structures. This research reports

an experimental work carried out to examine the collaps-

ibility behavior of residual laterite soils under cyclic drying

and wetting process, different initial water contents and dry

densities. A modified oedometer was employed to perform

air-drying and wetting cycle on the soil samples. The

results showed that the soil collapsed upon wetting at a

constant vertical stress. The collapse potential of the soil

increased initially to a maximum value with increasing

vertical stress and then decreased at higher levels of ver-

tical stress. The dryingwetting cycles caused a reduction

in void ratio and an increase in feasible cementation

bounds of the residual laterite soil. As a result, the collapse

potential diminished and the swell potential slightly

increased. Yet, the soil with high dry density not only did

not produce desirable results in reducing the collapsibility,

but also slightly increase the soil swelling under the wet-

tingdrying cycles.

Keywords Collapse/swell potential Wetting and air-drying cycles Residual laterite soil

Introduction

Soils that are susceptible to a great and sudden diminu-

tion in volume upon wetting are known as collapsible

soils. Single and double-oedometer method were pre-

sented to quantify volume change and collapsibility by

Fookes [1]. Numerous researchers (i.e. [2]) have studied

collapse and volume change behavior of soils upon

wetting or drying. Their studies showed that drying and

wetting cycle was one of the important factors to impact

particle cementation, water content, and void ratio of

soils. Furthermore, investigations on residual soils

revealed their collapse tendency due to wetting and

dryingwetting cycle [3].

Residual soils with extensive weathering are found in

most countries of the world, but the broader and deeper

regions can be formed in tropical humid zones. A kind of

residual soils is laterite soil which is widely founded in

Malaysia, with intense weathering and loading of soluble

minerals. The engineering characteristics of these soils

were altered considerably depending on factors such as

parent material, climate, topography, vegetation, and age

[1]. Their volume change due to change in moisture con-

tent (drying and wetting) is one of exceptional character-

istics of these soils. These kinds of soils are highly

susceptible to collapse upon wetting. Based on the reviews

done, there is no experiment examining the effects of

wettingdrying cycle on the collapse behavior of tropical

laterite soil fills. This study was conducted to evaluate the

effects of wetting and drying process on collapse potential

of compacted laterite soil samples from the Universiti

Teknologi Malaysia (UTM) campus in Johor, Malaysia.

Such a study will be useful to predict collapse potential of

compacted laterite soil fills subjected to foundations, roads,

and other structures.

M. Kholghifard (&) K. Ahmad N. Ali A. Kassim R. Kalatehjari

Department of Geotechnics and Transportation, Faculty of Civil

Engineering, Universiti Teknologi Malaysia, 81310 UTM

Skudai, Johor Baharu, Malaysia

e-mail: [email protected]

123

Natl. Acad. Sci. Lett. (MarchApril 2014) 37(2):147153

DOI 10.1007/s40009-013-0221-4

Materials and Methods

Basic Properties of the Soil

Reddish brown laterite soil samples for this study were

collected from a depth of 1.7 m within the UTM campus.

The tests were performed in Geotechnics lab of Civil

Engineering Department of UTM. Table 1 presents some

values obtained from basic experiments on the samples

based on British Standard (BS1377:1990) [4, 5]. Classifi-

cation tests employed according to BS [4] revealed that the

soil was clayey silt of high plasticity, MH. In addition,

X-ray diffraction analysis indicated that the representative

soil sample consisted of quartz, mica and feldspar as its

non-clay minerals, and kaolinite and montmorillonite as its

clay minerals. The maximum dry density and optimum

moisture content (OMC) of the soil obtained 1.41 Mg/m3

and 30 %, respectively, by use of standard compaction test.

Preparation of the Compacted Laterite Soil Specimens

Air dried representative soil specimens (passing 2 mm

sieve) were completely hand-blended with the designed

water contents. Then they were permitted to achieve

equilibrium for 24 h in sealed plastic covers. The required

mass of prepared wet soil samples were compacted to the

specified dry densities using hand-operated dynamic com-

paction based on BS [5]. The wet soil samples were pre-

pared to dry densities of 1.21 Mg/m3 with 85 % relative

compaction and initial water contents of 20 % (10 % dry of

OMC), 30 % (OMC), and 40 % (10 % wet of OMC) as

series A1, A2, and A3 respectively. In addition, other series

of samples were compacted to dry density of 1.35 Mg/m3

with 95 % relative compaction and water contents of 20, 30

and 40 % as series B1, B2 and B3 respectively (Table 2). It

should be noted that each series consisted of three identical

samples.

Wetting and Collapse Potential

Double-oedometer tests were carried out to determine the

collapse potential of the six series of laterite soil samples.

This method consists of performing two consolidation tests

on two identical samples. These identical samples were

placed into oedometers and kept under a small pressure

(1 kPa). One of the samples was initially fully saturated

and kept for 24 h, after which the sample was subsequently

loaded in standard incremental loading procedures up to

600 kPa. On the other hand, the other sample was incre-

mentally loaded up to 600 kPa at its initial water content.

The difference between void ratios of the saturated and

unsaturated samples was considered as the collapse

potential. The collapse potential was determined at vertical

stress levels of 12.5, 25, 50, 100, 200, 400, and 600 kPa for

samples of all the six series. The swell and collapse

potential (CP %) of the samples were computed from the

following equation defined by ASTM D 5333 [6] :

CP % De1 e0

100% 1

where e0 is initial void ratio, and De is the difference ofvoid ratios in unsaturated and saturated conditions (the

positive sign is for swelling situation, whereas the negative

sign is for collapse situation).

Wetting and Air-drying Cycles

The compacted laterite samples of the six series were

inserted in modified oedometer (Fig. 1) and subjected to

wetting and air-drying cycles.

Each sample was soaked with tap water at a small

pressure and kept for 24 h to complete saturation and

possible swelling. Subsequently, the water in the cell was

drained by suction and the sample was allowed to air dry at

30 5 C for 144 h (6 days). When the reading of the dialgauge used to measure settlement approximately achieved

Table 1 Basic properties of the soil sample

Property Value

Liquid limit (%) 68

Plastic limit (%) 35

Plasticity index (%) 33

Specific gravity 2.67

Sieve analysis and hydrometer

Gravel (%) 3

Sand (%) 36

Silt (%) 40

Clay (%) 21

Optimum moisture content, OMC (%) 30

Maximum dry density (Mg/m3) 1.41

Natural dry density (Mg/m3) 1.21

Natural water content (%) 26

Table 2 Properties of prepared samples

Series Dry density

(Mg/m3)

Compaction

(%)

Initial water

content (%)

A A1 1.21 85 20

A2 1.21 85 30

A3 1.21 85 40

B B1 1.35 95 20

B2 1.35 95 30

B3 1.35 95 40

148 M. Kholghifard et al.

123

a constant value, it was assumed the shrinkage of sample

was completed. The wetting and air-drying procedures

were repeated so that each sample was subjected to four

cycles of the wettingdrying. Samples subjected to four

wettingdrying cycles at small pressure are referred to as

desiccated sample [2].

Results and Discussion

Effect of Wetting on Collapse Potential of Laterite Soil

Samples

Double oedometer test was used to examine the effect of

wetting and evaluate the collapse potential of compacted

laterite soil samples. The difference between the dry and

the wet curves calculated as the collapse potential of the

soil [3] based on Eq. (1).

Figures. 2, 3 present the collapse potential against applied

load for samples of series A (A1, A2, A3) and B (B1, B2, B3)

respectively. In series A1 (with 85 % relative compaction),

samples with 20 % initial water content swelled around

0.5 % at pressure lower than 12.5 kPa, but they collapsed

under higher stress. The samples with 30 and 40 % initial

water content (series A2 and A3) did not swell at 12.5 kPa.

The collapse behavior for these samples began from

12.5 kPa. Comparatively, the results obtained from series

B1, B2, and B3 (with 95 % relative compaction) established

a lower degree of collapse potential in comparison to series

A1, A2, and A3. It can be observed that when the compacted

laterite soil samples under stress gained moisture, they

experienced collapse. This was probably as a result of dis-

solving or softening the bonds between particles of soil

which were reported by Fookes [1] and Lawton et al. [7].

The laterite residual soil under study had a natural dry

density around 1.3 Mg/m3 as shown in Table 1. So it was

acceptable that the void ratio was generally more than 1 for

all the soil samples. Generally, the compacted laterite

samples with lower values of initial water content indicated

slightly higher degree of collapse potential than those

samples with higher initial water content, however they all

experienced a lower degree of collapse potential under

higher levels of pressure. According to Bell and Culshaw

[8], the soil particles were rearranged into a more compact

state packing by the collapse process. It was also found that

all of the samples experienced reductions in the collapse

potentials at vertical stresses higher than 200 kPa. Such

phenomenon was caused by substantial compression of the

samples before their wetting [2, 7]. For the compacted

laterite soil, those samples with higher dry densities, lower

void ratio, and higher initial water content appeared to have

lower collapse potential.

Tables 3 and 4 indicate the severity of collapse [1] and

the degree of swelling [9], respectively. Based on collapse

potential classification of Fookes [1], the soil samples of

series A with 5 \ CP \ 12 % were classified as troubleand the B series with CP \ 5 % were classified as mod-erate trouble. Research by Yudhbir [10] discovered that the

great parts of collapsible soils are clayey silts and clayey

Fig. 1 Modified oedometer

Fig. 2 Collapse potential of the Series A (A1, A2, A3)

Fig. 3 Collapse potential of the Series B (B1, B2, B3)

Collapse/Swell Potential of Residual Laterite Soil 149

123

silty sand which agreed reasonably well with the types of

residual soils used in this study (MH for the laterite soil).

Lawton et al. [7] reported that compacted soils containing

between 10 and 40 % clay exhibited the highest collapse

potential. The compacted laterite soil samples in this study

consisted of about 21 % clay particles; therefore, the

moderate collapse potential for these soil samples was

expected.

Referring to the swelling pressure and percentage of

swell potential by Chen [9], all the samples in series A

(with swelling degree \0.9 %) and B (with0.2 % \ swelling degree \ 1 %) classified as low degreeof swelling.

Effect of Wetting and Air-drying Cycles on Swell

and Collapse Potentials of Laterite Soil Samples

Some of the properties of the compacted and desiccated

samples are shown in Table 5. After four wettingdrying

cycles, the desiccated samples achieved higher dry densi-

ties as well as lower void ratios and water contents in

comparison to the same compacted samples. The double-

oedometer method was employed to evaluate collapse

potentials of the desiccated laterite soil samples at pres-

sures of 12.5, 25, 50, 100, 200, 400 and 600 kPa for all the

six series. As can be seen Table 5, the void ratio of the

desiccated samples of series A1 diminished from 1.201 to

1.177 and the water content significantly decreased from 20

to 6.8 %.. Those changes came because of four wetting

drying cycles.

The swell and collapse behavior of series A and B

samples in both states of the compacted and desiccated are

illustrated in Figs. 4, 5, 6, 7, 8 and 9. In the swell/collapse

potential against vertical loads graphs, the vertical stresses

at which the samples did not undergo any vertical defor-

mation are defined as the swell pressures. The wetting and

Table 3 Collapse potential severity [1]

Collapse

potential (%)

Severity of problem

01 No problem

15 Moderate trouble

510 Trouble

1020 Severe trouble

[20 Very severe trouble

Table 4 Degree of soil swelling [9]

Likely

swelling (%)

Swelling

pressure (kPa)

Swelling

degree

[10 958 Very high310 239958 High

15 144239 Medium

\1 \48 Low

Table 5 Properties of the desiccated and compacted laterite soilsamples

Series Sample

condition

Dry density

(Mg/m3)

Property

Water

content (%)

Void

ratio

A1 Compacted 1.21 20.0 1.201

A1 Desiccated 1.23 6.8 1.177

A2 Compacted 1.21 30.0 1.201

A2 Desiccated 1.24 8.2 1.159

A3 Compacted 1.21 40.0 1.201

A3 Desiccated 1.27 13.1 1.106

B1 Compacted 1.34 20.0 1.001

B1 Desiccated 1.34 7.1 0.997

B2 Compacted 1.34 30.0 1.001

B2 Desiccated 1.34 9.0 0.995

B3 Compacted 1.34 30.0 1.001

B3 Desiccated 1.34 14.7 0.989

Fig. 5 Collapse potential of the Series A2 samples in the desiccatedand compacted condition



123

air-drying cycles caused the swell pressure of desiccated

samples of the series A1 rose from 15 to 17 kPa. On the

other hand, the desiccated sample swelled at 17 kPa which

was larger than the swell pressure of the compacted sample

(Fig. 4). The collapse potential of the desiccated samples

was lower than that of the compacted sample at the same

pressure except at high pressure (400 kPa) at which the

swell pressure was insignificantly exceeded.

The void ratio and initial water content of desiccated

sample of series A2 decreased from 1.201 to 1.159 and

from 30 to 8.2 % due to wettingdrying cycles, respec-

tively (Table 5). Comparing the desiccated samples and the

compacted samples belonging to series A2, the collapse

potential of the desiccated samples were also significantly

reduced at pressures from zero to 186.5 kPa, and increased

at high pressures from 186.5 to 400 kPa (Fig. 5). The void

ratio and water content of desiccated samples of series A3

were most influenced as their void ratios and water content

decreased from 1.201 to 1.106 and 40 to 13.6 % respec-

tively (Table 5). As shown in Fig. 6, the swell pressure of

desiccated samples remarkably increased. When A1 spec-

imens get moisture, they are highly collapsible in low

pressures. However, the soil was less collapsible in high

pressures as it had gained more compacted structure. As

soon as A2 and A3 specimens get moisture, they showed

less collapsibility in low pressure compare to the specimen

of A1 series.

The reduction in void ratio of desiccated samples of

series B due to wettingdrying cycles was negligible, while

their water contents were greatly declined (Table 5). Fig-

ures. 7, 8 and 9 showed that the laterite soil samples owned

by series B indicated a similar pattern as the series A

samples relating to changes in swell and collapse behavior

on wettingdrying cycles. The wettingdrying cycles

caused reduction in collapse potential of the A series. Yet,

the effect of wettingdrying cycle on high compacted soil

samples (B series) not only did not produce desirable

results in reducing the collapsibility, but also slightly

increased the soil swelling in the wettingdrying cycle.

This behavior was more significant in high pressures.

Referring to Table 6, the increase in severity of swell

potential of the desiccated laterite soil samples was because

of reduction in void ratio and water content. Relatively,

collapse potential of the laterite soil samples diminished


Fig. 7 Collapse potential of the Series B1samples in the desiccatedand compacted condition

Fig. 8 Collapse potential of the Series B2samples in t desiccated andcompacted condition

Fig. 9 Collapse potential of the Series B3 samples in the desiccatedand compacted condition


123

with decreasing their void ratio and increasing their water

content. Such observations were in agreement with those

observed by Tadepalli and Fredlund [11] and Rao and

Revanasiddappa [2]. Meanwhile, the collapse trend of the

desiccated laterite soil samples in Figs. 6, 9 indicate that

the void ratio changes were more influential than the

changes of water content, which is in line with the findings

of Rao and Revanasiddappa [2] on residual soil.

Work by Han [12] indicated that wettingdrying cycles

created cementation bonds consisted of magnesium, calcium,

aluminum, and iron compounds in residual soil samples. The

result of SEM analysis test shown in Fig. 10 indicated the

cementation bounds surrounding particles of the sample after

dryingwetting cycles.

In addition, inter particle contacts are strengthened by

cementation bonds which might cause extra resistance to

local shear forces induced by the applied loads. Conse-

quently, the collapse potentials were reduced. When the

applied vertical stresses exceed this extra resistance, the

desiccated samples have higher tendency to collapse than

the compacted samples (Figs. 4, 5, 6, 7, 8 and 9).

The energy dispersive X-ray spectroscopy analysis was

used to identify the elemental composition of the desic-

cated samples after dryingwetting cycles (Fig. 11). The

result indicated that the desiccated samples consisted of

magnesium, calcium, aluminum, and iron compounds,

which contributed forming cementation bounds as men-

tioned by Han [12].

Tables 6 and 7 show the collapse severity and swelling

degree of the compacted and desiccated laterite soil samples

based on the classification of Fookes [1] and Chen [9],

respectively. Comparing Tables 6 and 7, it can be concluded

that the wettingdrying cycle has a significant effect on the

collapsible behavior of laterite soils. The soil samples

belonging to the series A in desiccated condition compared

Table 6 Collapse severity of the compacted and desiccated laterite soil samples

Series Collapse potential (%) at 100 kPa Collapse severity (after Fookes [1])

Compacted condition Desiccated condition Compacted condition Desiccated condition

A1 -11.2 -7.4 Severe trouble Trouble

A2 -7.2 -4.0 Trouble Moderate trouble

A3 -2.9 -1.3 Moderate trouble No problem

B1 -3.0 -2.9 Moderate trouble Moderate trouble

B2 -2.4 -2.4 Moderate trouble Moderate trouble

B3 -1.0 -1.6 No problem Moderate trouble

Fig. 10 SEM micro fabric of laterite soil samples. a before dryingwetting cycles, b after dryingwetting cycles

Fig. 11 Energy dispersive X-ray spectroscopy result for the desic-cated samples


123

to compacted condition experienced significant reductions in

collapse potential value between 34 and 55 %. However, in

the case of series B these reductions were negligible. Hence

for series A, the soil samples that classified as severely

troublesome, troublesome, and moderately trouble soils in

compacted condition classified as troublesome, moderately

troublesome and non-problematic soils in desiccated con-

dition respectively. In addition, the swell pressures grew

from 015 to 1725 kPa for series A and from 1920 to

2242 kPa for series B. Their swell potentials improved

from 00.7 to 0.71 %.Therefore, wettingdrying cycles

slightly transmuted the low expansive residual laterite soils

to moderately swell soils especially in high dense conditions.

Conclusion

Laboratory experimental works indicated when residual

laterite soil samples were moistened, they showed collapse

behavior. It was also observed that at a constant dry density,

the collapse potentials of the soil samples increased initially

to a maximum value with increasing vertical stress and then

decreased approaching to the same point at a very high

vertical stress. The samples with lower initial water content

indicated a little higher rate of collapse potential than the

samples with higher initial water content. In contrast the

collapse potential experienced lower rate with growing

initial water content at high stress level. For higher dry

density of the soil a same behavior was confirmed except for

the value of collapse potential which decreased.

This experimental study established that wettingdrying

cycle has a significant effect on the collapsible behavior of

residual laterite soils. The wetting and drying cycle caused

reduction in collapsibility and increase in expansivity. Yet,

the soil sample with high dry density and maximum water

content not only did not produce desirable results in reducing

the collapsibility, but also slightly increase the soil swelling

under the wettingdrying cycles. This behavior was more

significant at high pressures. The void ratio changes were

more influential than the water content changes on the col-

lapse potential of the desiccated laterite soil samples.

References

1. Fooks PG (1990) Report on tropical residual soils. Q J Eng Geol

23:103108

2. Rao SM, Revanasiddappa K (2006) Influence of cyclic wetting

drying on collapse behavior of compacted residual soil. J Geotech

Geol Eng 24:725734

3. Benatti JCB, Miguel MG (2011) Collapsibility study for tropical

soil profile using oedometric tests with controlled suction. In:

Alonso EE, Gens A (eds) Unsaturated Soils. Taylor & Francis

Group, London, pp 193198

4. British Standards Institution (2007) BS 1377:1990. Part 2:

Classification tests. London

5. British Standards Institution (2007) BS 1377:1990. Part 4:

Compaction-related tests. London

6. American Society for Testing and Materials (ASTM) (2003) Test

method for measurement of collapse potential of soils. ASTM

standards, Philadelphia

7. Lawton EC, Fragaszy RJ, Hotherington MD (1992) Review of

wetting induced collapse in compacted soil. ASCE J Geotech Eng

118:13761394

8. Bell FG, Culshaw MG (2001) Problematic soils: a review from a

British perspective. In: Proceedings of the symposium on prob-

lematic soils, Nottingham, p 135

9. Chen FH (1988) Foundation on expansive soils. Elsevier, New

York

10. Yudhbir Y (1982) Collapsing behavior of collapsing soils. In:

Proceedings of 7th Southeast Asia geotechnical conference, Hong

Kong, p 915930

11. Tadepalli R, Fredlund DG (1991) The collapse behavior of

compacted soil during inundation. Can Geotech J 28:477488

12. Han YM (1995) An experimental study on preconsolidation

pressures induced by desiccation. In: Proceedings of 10th Asian

Regional Conference on soil mechanics and Foundation Engi-

neering. Beijing, p 2124

Table 7 Expansion degree of the compacted and desiccated laterite soil samples

Series Expansion (%) at 12.5 kPa Swell pressure kPa Expansion degree (after Chen [9])

Compacted

condition

Desiccated

condition

Compacted

condition

Desiccated

condition

Compacted

condition

Desiccated

condition

A1 0.4 0.9 15.0 17.0 Low Low

A2 0.0 0.7 0.0 18.2 Low Low

A3 0.0 0.6 0.0 25.0 Low Low

B1 0.7 1.0 19.8 22.0 Low Low

B2 0.3 0.7 19.2 25.0 Low Low

B3 0.2 1.2 20.5 42.0 Low Low


123

Collapse/Swell Potential of Residual Laterite Soil Due to Wetting and Drying-wetting CyclesAbstractIntroductionMaterials and MethodsBasic Properties of the SoilPreparation of the Compacted Laterite Soil SpecimensWetting and Collapse PotentialWetting and Air-drying Cycles

Results and DiscussionEffect of Wetting on Collapse Potential of Laterite Soil SamplesEffect of Wetting and Air-drying Cycles on Swell and Collapse Potentials of Laterite Soil Samples

ConclusionReferences

Documents

Laterite Soil Collapse Potential