Wall Friction

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89International Journal of Earth Sciences and Engineering

ISSN 0974-5904, Volume 04, No 06 SPL, October 2011, pp 89-93

#020410123 Copyright 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved

Study on soil structure interface strength property

Gireesha N. TPostgraduate student, Department of Civil Engineering, National Institute of Technology, Tiruchirappalli620015, India,

E-mail:[email protected]

K. MuthukkumaranAssistant Professor, Department of Civil Engineering, National Institute of Technology, Tiruchirappalli620015, India,

E-mail: [email protected]

ABSTRACT: In soil-structure interaction problems it often becomes important to make a good estimation offrictional resistance between ground and foundation. The interface friction angle of soil against structural materials is ofgreat interest among the researchers in soil structure interaction. This study conducts a series of direct shear tests to

investigate the interface friction angle of different structural materials (concrete, steel and wood) against well graded

sand and poorly graded sand with varying relative density. The experimental results showed that both internal friction

angle () of the sand and the interface friction angle () increases with increasing the relative density in both well gradedsand and poorly graded sand. The ratio of / is calculated for all the three (concrete, steel and wood) materials and

among these three materials concrete is gives the higher value. The soil gradation is significantly changes the interface

friction angle in all three materials.

Key words:Direct shear test, Sand, Internal friction angle, Interface friction angle

INTRODUCTION:The understanding of soil structure interface shear

strength is essential to the design and analysis of

structures. In the present study the direct shear test is usedto find the friction angle between sand and structural

materials. Among a number of studies on friction between

soil and construction materials, there are some on thefriction between the sand with concrete, steel and wood.

Based on the extensive experimentation, Potyondy (1960)

proposed to express the skin friction resistance in a similar

form to that of the Coulomb failure envelope as a sum ofthe adhesion and the normal stress dependent component.

In a study on the uplift capacity of piles, Esashi et al.

(1966) showed that skin friction coefficient between sandand construction material, such as steel, concrete, and

wood, would be a function of the quantified surface

roughness.While direct shear apparatus were used in the

above mentioned studies, Yoshimi et al. (1981) used aring torsion apparatus to overcome the disadvantages of

direct shear apparatus. It was found that the quantified

roughness of the metal surface could be correlated withthe frictional coefficient, irrespective of the sand density.

The several kinds of apparatus were used to investigate

the interfacial friction between sand and various

construction materials are direct shear test apparatus,

simple shear apparatus, ring torsion apparatus and dualshear apparatus. Several factors affecting the value of the

interface friction angle are: (i) soil properties such asmineralogical composition, density, grain shape, grain sizeand gradation; and (ii) the properties of the material

surface such as hardness and surface roughness.

The object of the present paper is to study the soilstructure interface strength property of sand with other

structural materials (concrete, steel and wood) with

varying relative density of sand. And also to study theeffect of gradation on interface strength.

NOTATIONS:

SYMBOL DESCRIPTION

SW : Well Graded Sand

SP : Poorly Graded Sand

: Angle of Internal Friction : Angle of Interface Fiction

Dr : Relative Density

d : Dry Density

EXPERIMENT TEST PROCEDURE:For the present study the direct shear test is used. The

direct shear test box of lower valve is filled with structural

material and upper valve is filled with sand of varying

density. the size of the structural material is

60mm*60mm*10mm, the sand used is local availablesand of different gradation.

The test apparatus setup as shown in Fig.1

Figure 1: Direct shear test apparatus setup


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90 Gireesha N. T, K. Muthukkumaran

International Journal of Earth Sciences and Engineering


RESULTS AND DISCUSSION:This test is carried out for the classification of sand and the

test was carried out as per IS: 1498(1970). Fig.2 shows the

particle size distribution of both well and poorly gradedsand. The properties of sand are presented in Table 1

Fig.2 Gradation curve for well and poorly graded sand

Table 1 Properties of sand

Effect of Gradation on Friction Angle

The friction angle depends on the surface roughness of the

material, type of sand, loading system and relative density.

In the present study the effect of particle size on thefriction angle investigated for different relative density.

The different relative densities are taken as relative

density corresponding to minimum and maximum densityof the soil and 50% of the maximum relative density.

Using the known relative density, the weight of sample

has been calculated to carry out the direct shear test.

Estimation of weight of sample for different relative

density d(min) is the density corresponding to the soil inloose state and d(max) is the density corresponding to the

soil in dense state. The d(min) is obtained by conducting

density test by sand replacement method where d(max) hasobtained by using vibrating the soil to the maximum

densification.

Relative density =

Angle of Internal FrictionThe variation of the angle of internal friction for both well

graded and poorly graded sand are shown in from Fig. 3

and Fig. 4 respectively. The percentages of reduction in ,for minimum and maximum relative densities are 9.8 and

9.9 respectively but for 50% Dr the percentage of

reduction is 8.9. From the Figures it is clearly seen that the

increasing relative density increases the angle of internalfriction for both well and poorly graded sand. However

the rate of change of friction angle is more in well graded

sand than poorly graded sand. The percentage of reductionin with respect to relative densities is presented in Table

2.

Fig. 3 for well graded sand

Fig. 4 for poorly graded sand

Table 2 for SW and SP

Properties

Well graded

sand

Poorly graded

sand

Uniformitycoefficient(Cu)

6.12 1.8

Coefficient of

curvature(Cc)1.86 0.89

Max. drydensity in g/cc

(dmax)

2.28 2.11

Min. dry

density in g/cc

(dmin)

1.74 1.71

Specificgravity(Gs)

2.64 2.58

Dr

Well

graded

sans

Poorly

graded

sand

% of

Reduction

in

Min

Dr 36.6 33 9.8

50%Dr 38.2 34.8 8.9

Max

Dr 40.1 36.1 9.9


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91Study on soil structure interface strength property



Interface Friction AngleIn the direct shear box the bottom portion is filled with

structural material and top portion is filled with soil. The

weight is varying due to the change in volume

Interface friction angle between sand and concrete

The variation of for well graded and poorly graded sand

is shown in Fig. 5 and Fig. 6 respectively. The value of/ for Max.Dr of well graded sand is 0.8 and for poorly

graded sand is 0.79. The Min.Dr of well graded sand has

low value of/ which is 0.76 as reported in Table 3

Fig. 5 for Concrete and SW

Fig. 6 for Concrete and SP

Table 3 and / for SW and SP of Concrete

Dr Well graded sand Poorly graded sand

in

degree

in

degree /

in

degree

in

degree /

Min Dr 36.6 28.1 0.76 33 25.9 0.78

50% Dr 38.2 30 0.78 34.8 27.5 0.79

Max Dr 40.1 32.1 0.8 36.1 28.8 0.79

Friction angle between sand and steelThe variation of for well graded and poorly graded sand

is shown in Fig 7 and Fig 8 respectively. The value of/

for Max.Dr of well graded sand is 0.78 and in poorlygraded sand is 0.79. The Min.Dr of well graded sand has

low value of/ is 0.75 as reported in Table 4

Fig. 7 for Steel and SW

Fig. 8 for Steel and SP

Table 4 and / for SW and SP of Steel

Interface friction angle between sand and wood

The variation of for well graded and poorly graded sandis shown in Fig. 9 and Fig. 10 respectively. The value of

/ for Max.Dr of well graded sand is 0.76 and in poorly

graded sand is 0.78. The value of/ for Min.Dr of wellgraded sand is 0.72 and in poorly graded sand is 0.76. The

well graded sand shows the lower value of / than the

poorly graded sand it is reported in the Table 5


in

degree

in

degree/

in

degree

in

degree/

Min Dr 36.6 27.5 0.75 33 25.6 0.77

50% Dr 38.2 29.6 0.77 34.8 27.2 0.78

Max40.1 31.5 0.78 36.1 28.7 0.79


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92 Gireesha N. T, K. Muthukkumaran



Fig. 9 for Wood and SW

Fig. 10 for Wood and SP

Table 5 and / for SW and SP of Wood

Fig. 11 and Fig. 12 shows the variation of interfacefriction angle () for different structural materials

(concrete, steel and wood) with both well graded and

poorly graded sand respectively. It shows that concretehas more interface friction angle compared to other two

materials of steel and wood in both well graded and poorly

graded sand.

Fig. 11 Variation for different materials with SW

Fig 12 Variation for different materials with SP

CONCLUSIONS

The following are the conclusions drawn from the presentstudy.

1. The angle of interface friction or wall frictionangle () increases with increase in relativedensity for both well graded sand and poorly

graded sand.

2. The soil gradation has significant effect on thewall friction angle (), for instant the / value is

0.80 for well graded soil and 0.7 for poorly

graded soil with maximum relative density in soilconcrete interface friction.

3. The well graded sand shows the lower value of/ than the poorly graded sand in soil woodinterface friction. The value of / is 0.76 and

0.78 for well graded and poorly graded sand

respectively in maximum relative density, where

has in minimum relative densities there valuesare 0.72 and 0.76.

4. Concrete has more interface friction anglecompared to other two materials of steel andwood in both well graded and poorly graded

sand.


in

degree

in

degree /

in

degree

in

degree /

Min

Dr36.6 26.7 0.72 33 25.4 0.76

50%Dr

38.2 29 0.75 34.8 27 0.77

Max

Dr40.1 30.7 0.76 36.1 28.4 0.78


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93Study on soil structure interface strength property



REFERENCES

[1] Abdullah I.Al-Mhaidib (2006), Influence of shearingrate on interfacial friction between sand and steel.

Engineering Journal of the University of Qater,

Vol.19

[2] API: 2000, Design and construction of pilefoundations.[3] Bosscher, P. J. and Ortiz, C. (1987), FrictionalProperties between Sand and Various Construction

Materials. Journal of Geotechnical Engineering,ASCE, Vol. 113, No. 9, pp. 1035-1039.

[4] Boulon M. (1989), Basic Features of Soil StructureInterface Behavior. Computers and Geotechnics 7,

115-131.[5] Hong, Z., and Hua, X, G. (1995), A study of

deformation in the interface between soil and

concrete. Computers and Geotechnics 71, 7592[6] Hsieh, C., Hsieh, M.W. (2003), Load plate rigidity

and scale effects on the frictional behavior of

sand/geo-membrane interfaces. Geotextiles and

Geomembranes 21(1), 2547.

[7] Lui, S.H., Dean Sun and Hajime Matsuoka (2005),On the interface friction in direct shear test.Computers and Geotechnics 32, 317325

[8] Nan Liu, Hsien Ho and Huang, W., (2009), Largescale direct shear test of soil/PET-yarn geogrid

interfaces. Geotextiles and Geomembranes 27, 19-30[9] ORourke, T. D., Drushel, S. J. and Netravali, A. N.,(1990), Shear Strength Characteristics of Sand-

polymer Interfaces. Journal of GeotechnicalEngineering, ASCE, Vol. 116, No. 3, pp. 451-469.

[10]Subba, Rao, K.S., Allam, M.M, Robinson, R.G,(1988), Interfacial Friction between Sand and SolidSurfaces. Geotechnical Engineering, Vol. 131, pp.

75-82.

[11]Uesugi, M., and Kishida, H., (1986), Influentialfactors of friction between steel and dry sands. Soiland foundations Vol.26, N0. 2, 33-46.

[12]Wang, Z., and Richwien, W., (2002), A study ofsoil-reinforcement interface friction. Journal ofGeotechnical and Geoenvironmental Engineering,

Vol.128 No.1

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Wall Friction