Performance Characteristics of Interfaces between Gravel Soils

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Performance Characteristics of Interfaces between Gravel Soils 
and Steel Surfaces by Shear Test

 
ABSTRACT 

Foundation engineering has traditionally concerned the utilization of wood, concrete, steel, or a mix of those construction materials. Friction between these construction materials with soil is of major significance to form an honest estimation of resistance resistance between soil and foundation. In friction piles, load is transferred to soil through interface friction between soil and pile material. This study conducts a series of direct shear tests to research the interface friction angle of structural material (steel) against well and poorly stratified gravel soils with varied surface roughness of steel specimens. Experimental results show that soil gradation and surface roughness of steel specimens were considerably changes the interface friction angle. Shear strength at the interface will increase with increase in traditional stress and surface roughness. This study are going to be useful to the researchers and active engineers operating in soil-structure interaction issues.

INTRODUCTION

In soil-structure interaction issues, the resistance resistance between soil associated structure is extremely necessary to possess an applicable system analysis. It involves estimation of stresses transferred on the interface between soils and solid surfaces. style of earth reinforcements involves the estimation of surface friction between soils and such structures. it's essential to work out the interface friction angle between soil and pile material so as to form an honest estimation of the axial capability of the pile. Also, data of the interface friction angle within the determination of the magnitude and line of action of the wall reaction is critical. to supply some insight into the surface behavior between steel and gravels, associate experimental study was performed to guage the importance of assorted factors. The behavior of the steel-gravel interfaces was additionally compared with the gravel-gravel interfaces. numerous studies on surface friction between soil and alternative materials were dole out within the past. completely different varieties of equipment were utilized in the literature to work out interface friction angle between soil and solid construction material. Uesugi associated Kishida [1] performed an experimental study of resistance resistance at yield between dry sand and steel. The results show that the cutting off resistance at the interface depends on the traditional stress; surface roughness and sand kind. Tsubakihara et al. [2] conducted laboratory tests on friction between cohesive soils and gentle steel; experimental results indicate that the friction depends on the roughness of steel. Tan et al. [3] studied the sand-geotextile interface shear strength by torsional ring shear tests. The experimental results show that the height friction angle measured by the direct shear equipment is larger than that measured by the ring shear equipment and also the peak friction happens earlier within the direct shear check than within the ring shear check. Hammoud and Boumekik [4] studied the surface cutting off between cohesive soils and solid materials. The results show that the cutting off resistance at the interface depends on the interface roughness, furthermore as on the properties of soils. Ling and Youg [5] dole out laboratory tests to work out the interface shear strength of Palm biodiesel contaminated sand with swish and rough steel surfaces. The experimental results show that the contribution of palm biodiesel content to interface shear strength is critical. Interface shear strength will increase with the rise of palm biodiesel content. Applied traditional stress and surface roughness have exceptional influence on the interface shear strength. The decrease in interface shear strength thanks to a rise in palm biodiesel content.

SOIL CHARACTERISTICS

Well and poorly stratified gravel soils were utilized in the study. Engineering properties of the gravel soils is listed in Table.1. The gravel soils were classified furthermore and poorly stratified in step with IS: 1498 – 1970.

TESTING APPARATUS 

The direct shear tests for this complete study were dole out in an exceedingly typical direct shear box equipment. The equipment consists of a 2 piece shear box of sixty metric linear unit x sixty metric linear unit in cross-sectional rests over slippy rollers supported by a loading frame and which may be pushed forward at a relentless rate by geared jack, driven by an electrical motor. The casing with its motor is employed with the step less speed management box. The speed management of the shear box is label in mm/min. check speed might be controlled by selecting the suitable gear from the gear box. The lower half the shear box is bolt command in position in an exceedingly instrumentation and also the higher half the box butts against a proving ring. the traditional stress to the specimen is by a vertical load hanger that rests on the yoke on top of the soil specimen, and hangs vertically downward allowing selected weights to be remained its loading pan. The shear force was measured by suggests that of a proving ring. The horizontal displacement of the soil specimen was measured with the assistance of a dial gauge.

TESTING METHODOLOGY 

For the interface resistance check, four steel specimens of size 6cm x 6cm x one.4 cm were ready. 3 completely different surface of steel (smooth, medium and rough) were fitly obtained by rubbing with a carbide waterproof paper sheet. Direct shear check was conducted between these specimens with gravel soils. Four completely different steel specimens ar shown in Figure one.The specimens were placed within the lower half the direct shear box and also the higher half the shear box was full of gravel soils at planned density. The changed direct shear check setup is shown in Figure a pair of.

When a cutting off force is applied to the lower box through the geared jack, the movement of the lower a part of} the box is transmitted through the specimen to the higher part of the box and therefore on the proving ring. The deformation in proving ring indicates the shear force. The horizontal displacement throughout the cutting off method is measured by mounting a dial gauge at the highest of the box. Samples were sheared at one.25 mm/min. for every tests four traditional stress zero.05 N/mm2, 0.10 N/mm2, 0.15 N/mm2 and zero.20 N/mm2 were used.

TEST RESULTS AND DISCUSSIONS

Surface roughness of the fabric is one in all the necessary factors that influence the shear strength parameters. Generally, Absolute roughness (Ra) is taken into account for calculative interface friction between 2 completely different materials. it's a live of the surface roughness of a fabric. This roughness is mostly expressed in units of length because the absolute roughness of the fabric. Surface roughness of steel specimens utilized in the study is given within the Table a pair of. The results obtained for the well and poorly stratified gravel soils beneath completely different traditional stresses were analysed to get the desired shear strength parameters. The obtained shear strength parameters ar conferred in Table three. Interface friction angle against surface roughness of steel specimens with well and poorly stratified gravel soils ar shown in Figure three and four severally. It indicates that interface friction angle will increase with the increment of the surface roughness of the steel specimens utilized in this study. the very best peak shear strength is achieved once the surface is rough.

CONCLUSIONS

Direct shear tests were conducted to research the interface friction angle between well and poorly stratified gravel soils with steel specimens. The tests were performed beneath four values of traditional stress zero.05 N/mm2 , 0.10 N/mm2, 0.15 N/mm2 and zero.20 N/mm2. Examining the info obtained from direct shear check, it might be seen that, the shear strength at the interface will increase with increase in surface roughness of steel specimens. The shear strength will increase with increasing traditional stress.

• Angle of interface friction between swish surface steel specimen with well and poorly stratified gravel soils were vi.30 % and 8.42 the concerns less than medium surface steel specimen. 
• Angle of interface friction between rough surface steel specimen with well and poorly stratified gravel soils were four.90 % and 4.30 % over medium surface steel specimen. 
• Angle of interface friction between epoxy coated steel specimen with well and poorly stratified gravel soils were ten.77 try to thirteen.18% less than medium surface steel specimen

REFERENCES

1. Uesugi, M., and Kishida, H. (1986). “Frictional resistance at yield between dry sand and mild steel.” Geotechnical Society, Soils and Foundations, 26(04), pp139-149.
2. Tsubakihara, Y., Kishida, H., and Nishiyama, T. (1993). “Friction between cohesive soils and steel.” Geotechnical Society, Soils and Foundations, 33(02), pp145-156.
3. Tan, S. A., Chew, S. H., and Wong, W. K. (1998). “Sand-geotextile interface shear strength by torsional ring shear tests.” Geotextiles and Geomembranes, 16, pp161-174.
4. Hammoud, F., and Boumekik, A. (2006). “Experimental study of the behavior of interfacial shearing between cohesive soils and solid materials at large displacement.” Asian Journal of Civil Engineering (Building and Housing), 07(01), pp63-80.
5. Ling, S. Y., and Youg, L. C. (2012). “Palmbiodiesel contaminated sand-steel interface testing with direct simple shear apparatus.” International Journal of Civil and Structural Engineering, 03(01), pp227-238.
6. Houchao Sun, Ping Yang (2015) “Monotonic Shear Mechanical Characteristics of Interface Layers between Frozen Soil and Structure” [J] Electronic Journal of Geotechnical Engineering, 2014(18):1053-1066.