1. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING AND
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 4, Issue 6, November – December, pp. 252-260
© IAEME: www.iaeme.com/ijciet.asp
Journal Impact Factor (2013): 5.3277 (Calculated by GISI)
www.jifactor.com
IJCIET
©IAEME
CHARACTERISTICS OF SOME GEOTECHNICAL PROPERTIES OF PILA
SPI AND INJANA SEDIMENTARY FORMATIONS, AT SHAQLAWA AREA,
NORTH IRAQ
Ahmed Shehab Al-Banna,
Dhahir Khalil Ali,
Hamed Hassan Abdullah
ABSTRACT
The Geotechnical properties are an import aspect of civil engineering projects. So many
construction and mining companies interest with such studies. In the present study, 18 limestone
samples from Pila Spi formation and another 19 sandstones samples from Injana formation were
collected from two limbs of a syncline situated northeast Shaqlawa city, north Iraq. The vp and vs
velocities with some geotechnical properties of these samples were investigated. It is concluded that
the geotechnical properties of the samples are varied depending on many significant factors include
water saturation, the relative location of the sample within the syncline limbs and lithology as well.
Each syncline limb has different geotechnical properties than the other due to the nature and degree
of stresses influencing each limb.
Keywords: Poisson's Ratio, Material Index, Pila Spi Formation, Injana Formation.
INTRODUCTION
Many studies discuss the direct relations of longitudinal and transverse wave velocities with
elastic modulus (Wyllie, 1954 and Dobrin, 1976). Other studies deal with the relation of wave
velocities with the geotechnical properties, that are required for civil engineering purpose (Al-Salihi,
1999; Keary et al. , 2002; Al-Banna et al., 2006; Ezdin et al., 2007; Al-khafaji, 2010; Al-kharsan et
al., 2011;Yagin , 2011; Al-Awsi, 2012; and Tezcan and Ozdemir, 2012).
The present study is an attempt to investigate the characteristic of samples of Pila Spi and
Injana Formations, that exposed at Shaqlawa area, northern Iraq with respect to geotechnical
properties (Figure -1 ). Such this study is use to encourage the engineer to design a suitable building
structure, through definition the proper basement rock which eventually leads to select a better
building material for constructions. It also gives an idea of the environmental impact (water
saturation) on the geotechnical parameters of rocks.
252

2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(IJCIET),
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
Figure -1: Location map of the study area
253

3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
TECTOINC AND GEOLOGY
Tectonically, the study area belongs to the low folded zone according to the tectoinc divisions
of Iraq. This zone contains many formations exposed to the surface of Neogene sedimentary rocks.
The core of most anticlines in the folded zone include a sedimentary rocks of upper Cretaceous and
Eocene.
Pila Spi Formation is lagoonal facies belongs to the late lower Eocene –upper Eocene. The
upper part of the formation is well bedded crystalline limestone, while the lower part shows well
bedded hard, porous, limestone (Buday, 1980).
Injana (formally upper Fars) formation is accepted as upper Miocene in age. This formation
is variable from silty marlstone or claystone, medium to coarse grained sandstone (Jassime and Goof,
2006).
SAMPLE COLLECTION AND PROCESSING
Samples were collected from two limbs of the syncline which is situated at the northeastern
side of Shaqlawa city (Figure-1). The number of samples have been collected from the two
formations within the syncline are shown in table- 1.
Table-1: Number of Collected Samples in the Study Area, Northeast of Shaqlawa City
Location
Pila Spi Formation
Injana Formation
Northeastern limb
9
11
Southwestern limb
9
8
All the samples were processed to measure the physical properties. A cylindrical samples are
introduced with diameter of 7.6 cm and length range (8-16) cm. The surface of the two sides of each
cylindrical sample is smoothed using a special Grinder, according to ASTM 1987, in order to
measure the seismic wave velocity.
Ultrasonic device (New sonic viewer model- 5217A) is used to measure the P-wave and Swave in the laboratories of the Department of Geology in the University of Baghdad. The
longitudinal velocity (Vp) and transverse velocity (Vs) for all the samples are measured in two stages.
The first stage where the samples are dry, whereas the second where they are fully saturated with
water. The samples were considered fully saturated after they immersed in water for more than 48
hours.
The theoretical relations of considered parameters
The theoretical relations between the seismic velocity of longitudinal and transverse waves
and some geotechnical properties are modified to obtain the average value of the considered
formations.
The present study focuses on the determining of Poisson's ratio (σ), Material index (Im), and
the effective angle of internal friction (ϕ ).
Poisson's ratio (σ) is the ratio of frictional transverse contraction to the fractional extension
(Bowles, 1984). The parameters calculated using the following equation:
଴.ହሺ୚୮⁄୚ୱሻ^ଶିଵ
ሺ୚୮⁄୚ୱሻ^ଶିଵ
Poisson's ratio (σ) =
(Dominco, 1984)
254

4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
The equation above is a graph of Vs2 (x-axis ) and Vp2 (y- axes) ,for each case was plotted
the modified as below to obtain the average values of Poisson's ratio (σ).
଴.ହሺ௦௟௢௣௘ሻିଵ
Poisson's ratio (σ) =
௦௟௢௣௘ିଵ
Material index (Im): It respect the degree of material efficiency . It is influenc by material
content , degree of the consolidation , joints, fracture and existence of liquid in pore, which influence
the elasticity of materials. (Abdel Rahman et al, 1994).
ଷି ሺ୚୮⁄୚ୱሻ^ଶ
Material index (Im)= ሺ୚୮⁄୚୮ሻ^ଶିଵ
The slope of the graph of Vp2/Vs2 was used to modified the equation above in another
form(as below ) To obtain the average value of material index (Im).
ଷି௦௟௢௣௘
Im =௦௟௢௣௘ିଵ
The effective angle of internal friction (ϕ )
Is an important geotechnical properties. It is possible to measure this angle in the laboratory
by using Mohr's circles in triaxial test . This angle is use for evaluat the engineering properties of soil
and rocks.
Sin ϕ = 1 െ ቀ
Thus
ሺ୚୮⁄୚ୱሻ^ଶିଶ
ሺ୚୮⁄୚ୱሻ^ଶ
ቁ
ିଶ
Sin ϕ = ሺ୚୮⁄
୚ୱሻ^ଶ
As the slope of the plotted graph between Vp2 and Vs2 represent Vp2/Vs2 the Sin ϕ was calculated
according to the following equation .
ିଶ
Sin ϕ = ௦௟௢௣௘
RESULT AND DISCUSSION
The longitudinal and transverse wave velocities of the considered samples were measured
and plotted for Vp2 versus Vs2 for both case dry and fully saturated samples . The results of the dry
and saturated sample of Pila Spi formation on both limb are illustrat in figures- 2, Figure- 3 show the
results of sandstone samples collected from Injana formation in case of dry and saturated samples on
both side of the syncline.
The mean values of all the studied cases were computed and summarized in Table- 2.
255

5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
20000000
(m/sec)^2
24000000
14000000
12000000
16000000
Vp^2
Vp^2
(m/sec)^2
16000000
10000000
12000000
8000000
8000000
3000000
3500000
4000000
4500000
Vs^2
5000000
5500000
6000000
4000000
5000000
(m/sec)^2
6000000
7000000
8000000
Vs^2 (m/sec)^2
PilaspiFn
Pilaspi Fn.
Dry case
Dry case
Southwestern limb
Northeastern limb
Slope= Vp2 = 3.00667952 * Vs2 - 2816826.024
Slope=Vp2 = 2.785257566 * Vs2 - 772244.5231
Corr. Coeff. = 0.95
Corr. Coeff.= 0.98
13000000
18000000
16000000
12000000
Vp^2 (m/sec )^2
Vp^2 (m/sec)^2
14000000
12000000
11000000
10000000
10000000
9000000
8000000
6000000
8000000
2000000
3000000
4000000
5000000
6000000
Vs^2 (m/sec)^2
2000000
2400000
2800000
3200000
3600000
4000000
Vs^2 (m/sec )^2
PilaspiFn
PilaspiFn
Saturated case
Saturated case
Southwestern limb
Northeastern limb
Slope=Vp2 = 2.881541654 * Vs2 + 942619.3444
Slope=Vp2 = 2.785722779 * Vs2 + 2167125.688
Corr. Coeff. =0.96
Corr. Coeff. =0.97
Figure -2: Relationship between Vp2/Vs2 for Pila Spi formation of the syncline (east of Shaqlawa)
displays the average values of the Geotechnical properties .
256

6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
8000000
8000000
6000000
Vp^2 ( m/sec)^2
Vp^2 ( m/sec)^2
6000000
4000000
4000000
2000000
2000000
0
400000
800000
1200000
1600000
2000000
400000
800000
1200000
Vs^2 ( m/sec)^2
1600000
2000000
Vs^2 ( m/sec)^2
InjanaFn
Injana Fn.
Dry case
Dry case
Southwestern limb
Northeastern limb
Slope= Vp2 = 3.941537118 * Vs2 - 2769.435304
Slope=Vp2 = 4.405610867 * Vs2- 426360.3182
Corr. Coeff. = 0.99
Corr. Coeff.= 0.98
2500000
2000000
2000000
Vp^2 (m/sec)^2
Vp^2 ( m/sec)^2
1600000
1500000
1000000
1200000
800000
500000
0
400000
0
200000
400000
600000
800000
100000
200000
Vs^2 ( m/sec)^2
300000
400000
500000
600000
Vs^2 (m/sec)^2
InjanaFn
InjanaFn
Saturated case
Saturated case
Southwestern limb
Northeastern limb
Slope=Vp2 = 3.605746746 * Vs2 - 15912.
Slope=Vp2 = 3.819683643 * Vs2 - 55488.2537
Corr. Coeff. =0.99
Corr. Coeff. =0.98
Figure -3: Relationship between Vp2/Vs2 for Injana formation of the syncline (east of Shaqlawa
displys the average values of the Geotechnical properties)
257

7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
Table -2: Summary of the ratio of Vp2/Vs2 and mean values of the considered Geotechnical
properties for limestone samples of Pila Spi formation and sandstone samples of Injana formation,
northeast of Shaqlawa city
Parameters
Mean
values
Vp2/Vs2
Poisson's
Material
The effective
ratio (σ)
index (Im)
angle of
internal friction
Sample
(ϕ )
Type
Location
and station
Pilaspi (Lst.)
NE, dry
2.8266
0.226
+0.094
45°
Pilaspi (Lst.)
SW, dry
3.0066
0.251
- 0.0032
42°
Pilaspi (Lst.)
NE, saturate
2.7857
0.2199
+0.120
45.9°
Pilaspi (Lst.)
SW, saturate
2.8815
0.234
+0.0629
44°
Injana (S.st.)
NE, dry
4.4056
0.3431
- 0.412
27°
Injana (S.st.)
SW, dry
3.9415
0.3299
- 0.3199
30°
Injana (S.st.)
NE, saturate
3.81968
0.3226
- 0.2905
31.6°
Injana (S.st.)
SW, saturate
3.6057
0.3081
- 0.2324
33.7°
The results shown in table-2 were interpreted, then the conclusions can be conclude as follows:
1- Generally the mean values of the ratio Vp2/Vs2 in limestone samples of Pila Spi formation is
lower than that value in sandstone samples of Injana Formation
2- The Poisson's ratio of limestone of Pila Spi formation is lower than that of sandstone of Injana
formation which indicat that the limestone rocks is stronger than sandstone rocks in the study
site.
3- The mean value of Material index (Im) of sandstone samples of Injana formation were
classified within the category (I) according to Abdel Rahman (1989) classification , which
indicates relatively weak rocks. The mean values of Material index (Im) of limestone Pila Spi
formation were considered within the category (III) according to Abdel Rahman (1989) that
indicat relatively hard rocks.
258

8. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
4- The effective angle of internal friction of limestone of Pila Spi formation is greater than that
of sandstone of Injana formation indicating relative weakness of sandstone comparing with the
limestone.
5- The mean values of Vp2/Vs2 and Poisson's ratio (σ) decrease in the saturated samples relative to
the dry samples for both formations.
6- The mean values of Material index (Im) and the effective angle of internal friction (ϕ) increase
with the saturated samples relative to the dry samples for both formations.
7- The samples on the two limbs of Syncline shows a slight variation in the Geotechnical
properties. Generally, limestone samples of Pila Spi formation shows an increase in the values
of Vp2/Vs2and Poisson's ratio (σ) at the southwestern limb relative to the northeastern limb. The
Material index (Im) and the effective angle of internal friction (ϕ) decrease in the southwestern
limb of syncline.
On the other side, the mean value of Vp2/Vs2 , Poisson's ratio and Material index (Im) for
sandstone samples of Injana formation decreases at the southwestern limb of the syncline relative to
the other limb. The effective angle of internal friction (ϕ) shows increase values at the southwestern
limb relative to the northeastern limb of the study syncline northeast of Shaqlawa city.
Finally, it is easily concluded that the geotechnical properties are varied relative to the
lithology and saturation.
The important conclusion obtained from the present study is the variance of Geotechnical
values on the opposite side of the syncline. The last conclusion may be related to the relative stresses
which effect to the structure.
In the present study, the stresses cause the syncline structure effecting the northeast side more
than the southwest side, considering the line of collision of Arabian and Iranian plates at the
northeastern side of the studied area.
So, It is recommended to carried out an individual study for each site on the field, in order to
obtain the actual physical or Geotechnical properties rather than using theoretical values which
concealed many effective parameters. The authors believe that the physical properties actually
changed from one meter to another, relative to the lithology, saturation, stresses and other unknown
factors.
REFERENCES
1.
2.
3.
4.
5.
Abdel Rahman M. (1991), Rock material competence assessed by seismic measurement with
emphasis competence scale and application in some urban area in Yeman, E.G.S., proceedings
of 9th Ann. Meet, p206-228.
Al-Awsi,M.Dh.(2012), Geotechnical evaluation of Tikrit university site using geophysical
methods, Ph.D. thesis, university of Baghdad, 170p.
Al-Banna, A.Sh., Al-khafaji, A.J. and Banno, E.S.(2006), Seismic refraction and cross-hole
technique for investigate the top soil and water table beneath the high pumping station Hall of
Al-Hussian water supply station, Kerbala, Iraq. Journal of Kerbala university, vol.4, No.4,
pp33-42.
Al-khafaji, A.J. (2010), Geophysical and Geotechnical investigation of soil underneath the
foundation of Al-Abbas holy shrine site in KerbalaGovernorate, Ph.D. thesis, university of
Baghdad, 163p.
Al-Kharsan ,E.,Khorshid ,S.Z. and Faraj, H.H.(2011), Determination some of physical and
Geotechnical properties of calcareous rock in Kufa quarry using Ultrasonic velocities , Iraq,
National J. of Earth sciences , vol.11, No.2,pp11-36.
259

9. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Al-Salihi, M.A.(1999) Measurmentsof some Geotechnical properties by using refracted Pwave and S-wave for selected site between Baiji and Samarra, M.Sc. thesis (in Arabic),
university of Baghdad, 153p.
Bowles, J.E.(1984), physical and Geotechnical properties of soil, McGraw Hill, international
Book company, London, 578p.
Buday , T.(1980), The regional Geology of Iraq, 1: Stratigraphy and Palaeogeography, Dar
Al-Khutib publishing House , Baghdad ,Iraq. 445p.
Cernica ,J.N.(1995), Geotechnical engineering soil mechanics , USA, 435p.
Dobrin, M.B.(1976), introduction to geophysical prospecting , McGraw Hill, Book company
,Third edition ,New York , 6308p.
Dominco, S.N.(1984), Rock lithology and porosity determination from shear and
compressional wave velocity , Geophysics,vol.49,pp1188-1195.
EzEldin ,M.A., Tang ,H.,Bahwi, N. and Faraw, A.G.(2007), Geological soil and rock mass
evaluation for proposed hydroelectric power Plant at Sennar Dam, Sudan , Journal of applied
science , vol.7, No.22,pp3477-3484.
Holtz, R.D. and Kovacs, W.D.(1981), An introduction to Geotechnical engineering, Pergamon
press, 733p.
Jassim, S.Z. and Goof.(2006), Geology of Iraq, Dolin, Prague and Moravia, Brno, Czech
Republic, pp 71-83.
Kearey, Ph., Brooks, M. and Hill, I.(2002)an introduction to geophysical exploration,
Blackwell Publishing company, 262p.
Tezcan, S.S., and Ozdemir, Z.(2012), Allowable bearing pressure in soil and rocks through
seismic wave velocities. Earth science Research vol.1, No.1, www.ccsenet.org/esr.
Wyllie, M.R., Gregory, A.R. and Gardner, G.H.(1958), An experimental investigation of
factor affecting elastic wave velocities in porous media , Geophysics vol.23, pp 459-493.
Yagin,S.(2011), P- wave velocity test for assessment of Geotechnical properties of some rock
materials, Bull.Mater.Sci.vol.34, No.4, pp 947-953. Indian Academy of science.
Sivaramulu Naidu.D, Madan Mohan Reddy.K and Vijaya Sekhar Reddy.M, “Studies on
Chemical and Geotechnical Properties of Marine Sand”, International Journal of Advanced
Research in Engineering & Technology (IJARET), Volume 4, Issue 2, 2013, pp. 75 - 80,
ISSN Print: 0976-6480, ISSN Online: 0976-6499.
H.P. Singh, “Effects of Surcharge Loads on Liquefaction Parameters of Pond Ash Improved
with Stone-Sand Columns”, International Journal of Civil Engineering & Technology
(IJCIET), Volume 4, Issue 4, 2013, pp. 225 - 235, ISSN Print: 0976 – 6308, ISSN Online:
0976 – 6316.
260