The present work is focused on understanding the uplift capacity of vertical and inclined piles passing through two layered soil and subjected to the inclined loads. The study was carried out using finite element software MIDAS 3D. The foundation soil was modeled as an elasto-plastic material obeying the Mohr-Coulomb failure criterion. The parametric studies were performed by varying the diameter of pile, angle of inclination of load (α) and pile angle (θ). It was observed that the uplift capacity of pile depends upon these parameters. The uplift capacity of pile varies with inclination of pile angle and inclination of load.

1. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
ISSN 0976 – 6316(Online), Volume 6, Issue 3, March (2015), pp. 118-131 © IAEME
132
UPLIFT CAPACITY OF PILES IN TWO LAYERED SOIL
Sunil S. Pusadkar
Associate Professor, Govt. College of Engineering, Amravati, India
Sachin N. Ghormode
M. Tech. (Geotech) Scholar, Govt. College of Engineering, Amravati, India
ABSTRACT
The present work is focused on understanding the uplift capacity of vertical and inclined piles
passing through two layered soil and subjected to the inclined loads. The study was carried out using
finite element software MIDAS 3D. The foundation soil was modeled as an elasto-plastic material
obeying the Mohr-Coulomb failure criterion. The parametric studies were performed by varying the
diameter of pile, angle of inclination of load (α) and pile angle (θ). It was observed that the uplift
capacity of pile depends upon these parameters. The uplift capacity of pile varies with inclination of
pile angle and inclination of load.
Keywords: Inclined loads, Inclined pile, MIDAS 3D, Piles, Two layer soil
1. INTRODUCTION
Uplift forces acts on the supporting piles if structure such as dry docks, basements and
pumping stations are constructed below the water table. Uplift forces may be exerted on piles due to
swelling of the surrounding soils. Therefore, studying the behavior of piles under uplift forces as
well as the parameters affecting the uplift capacity of piles is of most important. When the piles are
inclined at an angle to the vertical they are called as batter piles. Batter piles are quite effective for
taking inclined load. A number of investigations have been performed numerically as well as
experimentally to determine the uplift capacity of piles. Chattopadhyay and Pise [1, 2], Patra et al.
[3], Abdullah I. [4], Bose et al. [5], Shankar et al. [6], Verma et al. [7], and Chae et al. [8] used
numerical methods such as limit equilibrium approach, curved failure surface, finite difference and
finite element methods or conduct laboratory model experimental tests to study the uplift capacity of
single pile and pile groups under compressive loads and pure uplift loads.
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2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
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133
Chattopadhyay and Pise [1,2] was shows that the ultimate uplift capacity of inclined pile increases
with increase in inclination of pile and decreases after reaching maximum value of αL at α=(15° to
22.5°). Bose et al. [5] found out net ultimate pullout capacity increases significantly with increase in
length to diameter ratio. Pullout capacity also increases with increase in diameter.
The uplift capacity of vertical piles subjected to vertical load and compressive load studied
by many researchers and reported that the uplift capacity decreases with increase in compressive
load, and also it depends upon various parameters. However, limited studies observed on uplift
capacity of inclined piles subjected to inclined loads. Therefore, in this paper, attempts has been
made for detailed study of uplift capacity of vertical pile and inclined pile in two layer strata
subjected to inclined uplift load.
2. PROBLEM STATEMENT
The uplift capacity of vertical piles inclined piles subjected to inclined load are determined
by using MIDAS 3D which works on finite element approach. Two layer soils assumed to be made
of clay resting on sand. The properties of clay and sand used in the MIDAS 3D analysis are shown in
Table 1, while the pile properties are shown in Table 2.
Table 1: Soil properties
Sr. No Properties Clay Sand
1 Unsaturated unit weight (kN/m3
) 17 19
2 Dry unit weight (kN/m3
) 16 18
3 Cohesion c (kN/m2
) 40 1
4 Poisson’s ratio ν 0.35 0.3
5 Young’s modulus E (kN/m2
) 15000 30000
6 Angle of Internal Friction φ 0 35
7 Material model Mohr Coulomb Mohr Coulomb
8 Type of material behavior Un-drained Drained
Table 2: Pile properties
Sr. No Parameter Values
1 Young’s modulus E (kN/m2
) 2x108
2 Dry unit weight (kN/m3
) 25
3 Poisson’s ratio ν 0.15
The soil model, pile and load on pile are shown in Fig. 1. The soil model of size 15m X 10m
was used in the analysis. The various combinations of load and pile which were used for analysis are
shown in Fig. 1.
(a) Vertical pile and vertical load (b) Inclined pile and vertical load

3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
ISSN 0976 – 6316(Online), Volume 6, Issue 3, March (2015), pp. 132-138 © IAEME
134
(c) Vertical pile and inclined load (d) Inclined pile and inclined load
Figure 1: Problem statement models
The pile in circular shape with 5m length was considered for the analysis. The other
parameters such as diameter of pile, inclination of pile and loads are given in Table 3. The
constitutive soil model used in MIDAS 3D analysis was Mohr-Coulomb.
Table 3: Parameters for study
Case Parameters Remarks
1 Shape, size and length of piles Length = 5m; Diameter = 0.3, 0.6,
0.9m; Shape = Circular
2 Inclined angle of piles 0⁰, 5⁰, 10⁰, 15⁰, 20⁰, 25⁰, 30⁰.
3 Inclination of loads 0⁰, 5⁰, 10⁰, 15⁰, 20⁰, 25⁰, 30⁰.
3. ANALYSIS
The analysis of pile in two layered soil mass was carried out using MIDAS 3D. The pile was
taken as beam structure made of concrete and assumed to be a linear elastic material. The analysis
was carried out on weak over strong soil where upper soil layer was taken as half the length of pile.
Fig. 2 shows the soil model, pile geometry model and mesh generated in MIDAS 3D software. The
same soil model was used for all analysis for all parameter studied.
Figure 2: Soil and pile geometry model

4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
ISSN 0976 – 6316(Online), Volume 6, Issue 3, March (2015), pp. 132-138 © IAEME
135
4. RESULTS AND DISCUSSION
The analysis was carried out in MIDAS 3D using soil model and soil properties as discussed
above for uplift capacity of pile subjected to inclined load in two layered soil. The results were
plotted between uplift capacity obtained from load displacement curve and inclination of load with
vertical (α) for different pile angle (θ) and also for uplift capacity versus batter angle (θ) for various
diameters.
4.1 Effect of Diameter and Load Inclination
The effect of diameter and batter angle (θ) on uplift capacity of pile are shown in Fig. 3. The
uplift capacity of pile increases as diameter increases. For batter angle 0⁰and 20⁰ to 30⁰ uplift
capacity increases with increase in load inclination angle and then decreases. For batter angle 5⁰ to
15⁰ the uplift capacity decreases initially and then increases.
1300
1400
1500
1600
1700
1800
0 20 40
UpliftCapacity(kN)
Load Inclination Angle(α)
θθθθ=0⁰⁰⁰⁰
D=0.3m
D=0.6m
D=0.9m 1100
1200
1300
1400
1500
1600
1700
1800
0 20 40
UpliftCapacity(kN)
Load Inclination Angle(α)
θθθθ=5⁰⁰⁰⁰
D=0.3m
D=0.6m
D=0.9m
1200
1300
1400
1500
1600
1700
1800
0 20 40
UpliftCapacity(kN)
Load Inclination Angle(α)
θθθθ=10⁰
D=0.3m
D=0.6m
D=0.9m 1300
1400
1500
1600
1700
1800
1900
0 20 40
UpliftCapacity(kN)
Load Inclination Angle(α)
θθθθ=15⁰⁰⁰⁰
D=0.3m
D=0.6m
D=0.9m

5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
ISSN 0976 – 6316(Online), Volume 6, Issue 3, March (2015), pp. 132-138 © IAEME
136
Figure 3: Variation of uplift capacity and load inclination angle (α)
4.2 Effect of Pile Inclination
Fig. 4 shows the graphs between uplift capacity and batter angle of pile. For vertical load the
uplift capacity increases with increase in batter angle upto 15⁰ and then decreases. For load
inclination angle of 5⁰ to 15⁰ the uplift capacity decreases then increases but for pile inclination 20⁰-
30⁰ it continuously decreases.
1200
1300
1400
1500
1600
1700
1800
0 20 40
UpliftCapacity(kN)
Load Inclination Angle(α)
θθθθ=20⁰⁰⁰⁰
D=0.3m
D=0.6m
D=0.9m
1300
1400
1500
1600
1700
1800
1900
0 20 40
UpliftCapacity(kN)
Load Inclination Angle(α)
θθθθ=25⁰⁰⁰⁰
D=0.3m
D=0.6m
D=0.9m
1200
1300
1400
1500
1600
1700
1800
1900
2000
0 20 40
UpliftCapacity(kN)
Load Inclination Angle(α)
θθθθ=30⁰⁰⁰⁰
D=0.3m
D=0.6m
D=0.9m
1000
1200
1400
1600
1800
2000
0 20 40
UpliftLoad
Batter Angle(θθθθ)
α=0⁰
D=0.3m
D=0.6m
D=0.9m

6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
ISSN 0976 – 6316(Online), Volume 6, Issue 3, March (2015), pp. 132-138 © IAEME
137
Figure 4: Uplift capacity versus batter angle (θ) for l=5m
1000
1200
1400
1600
1800
2000
0 20 40
UpliftLoad
Batter Angle(θθθθ)
α=25⁰
D=0.3m
D=0.6m
D=0.9m
1000
1200
1400
1600
1800
0 20 40
UpliftLoad
Batter Angle(θθθθ)
α=20⁰
D=0.3m
D=0.6m
D=0.9m
1000
1200
1400
1600
1800
2000
0 20 40
UpliftLoad
Batter Angle(θθθθ)
α=15⁰
D=0.3m
D=0.6m
D=0.9m1000
1200
1400
1600
1800
2000
0 20 40
UpliftLoad
Batter Angle(θθθθ)
α=10⁰
D=0.3m
D=0.6m
D=0.9m
1000
1200
1400
1600
1800
2000
0 20 40
UpliftLoad
Batter Angle(θθθθ)
α=30⁰
D=0.3m
D=0.6m
D=0.9m

7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),
ISSN 0976 – 6316(Online), Volume 6, Issue 3, March (2015), pp. 132-138 © IAEME
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5. CONCLUSIONS
• The uplift capacity is increases with increase in diameter.
• For vertical pile the maximum uplift capacity is observed at load inclination of 20⁰.
• The uplift capacity varies with load inclination angle
• The uplift capacity varies with inclination of pile.
REFERENCES
1. Chattopadhyay B.C. and Pise P.J. (1986): ‘Uplift capacity of piles in sand’, J. Geotech.
Engrg., ASCE, 112:888-904.
2. Chattopadhyay B.C. and Pise P.J. (1986): ‘Axial uplift capacity of inclined piles’, Indian
Geotechnical Journal, ASCE, Vol.16, No. 3, pp.198-213.
3. Patra N.R., Deograthias M., and James M. (2004): ‘Pullout Capacity of Anchor Piles’, EJGE,
Vol. 05 [2004], Bund. K.
4. Abdullah I. and Al-Mhaidib (2009): ‘Uplift capacity of model piles under different
percentages of compressive loads’, 2nd International Conference on New Developments in
Soil Mechanics and Geotechnical Engineering, 28-30 May 2009, Near East University,
Nicosia, North Cyprus.
5. Bose Kimi K. and Krishnan A. (2009): ‘Pullout capacity of model piles in sand’, IGS
Chennai Chapter, Students paper competition.
6. Shankar K., Basudhar P.K. and Patra N.R. (2009): ‘Uplift Capacity of Pile Groups Embedded
In Sand’, IGC 2009, Guntur, INDIA.
7. Verma, A.K. and Joshi, Ronak (2010): ‘Uplift Load Carrying Capacity of Piles in Sand’,
Indian Geotechnical Conference – 2010, GEOtrendz December 16–18, 2010. IGS Mumbai
Chapter & IIT Bombay.
8. Chae D., Cho W. and Hyung-Yoon Na (2012): ‘Uplift Capacity of Belled Pile in Weathered
Sandstones’, International Journal of Offshore and Polar Engineering (ISSN 1053-5381) Vol.
22, No. 4, December 2012, pp. 297–305.