Numerical investigation of pile-head load effects on the negative skin friction development of a single pile in consolidating ground

In order to study influences of different load at pile top on the behaviors of negative skin friction piles, field tests of negative skin friction behaviors of three identical piles with different loads at pile top are made in the same site. According to the field test condition, the corresponding numerical simulations are accomplished. The comparison shows that numerical simulation results and field test results in accordance well. The additional settlement induced by negative skin friction is bigger and the neutral position is higher, the additional axial force induced by negative skin friction reduces obviously in piles with pile head load compared with that in piles without pile head load induced by negative skin friction. Along with load increase, the additional settlement increases, the neutral point position becomes higher; the additional axial force reduces obviously. The result indicates there is regularity about the influences of pile head load on negative skin friction. It may be useful to the research for negative skin friction behaviors of pile.

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Negative Skin Friction Distribution on a Single Pile - Numerical Analysis

Sustainability Issues for the Deep Foundations - Sustainable Civil Infrastructures ◽

10.1007/978-3-030-01902-0_4 ◽

2018 ◽

pp. 36-48 ◽

Cited By ~ 1

Author(s):

Talal Awwad ◽

Salma Al Kodsi ◽

Alexey Shashkin

Keyword(s):

Numerical Analysis ◽

Skin Friction ◽

Single Pile ◽

Negative Skin Friction

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Down-drag on Piles in Clay due to Negative Skin Friction

Canadian Geotechnical Journal ◽

10.1139/t72-037 ◽

1972 ◽

Vol 9 (4) ◽

pp. 323-337 ◽

Cited By ~ 51

Author(s):

Bengt H. Fellenius

Keyword(s):

Skin Friction ◽

Soft Clay ◽

Clay Layer ◽

Bending Moments ◽

Pile Head ◽

Design Rules ◽

Negative Skin Friction ◽

Negative Friction ◽

One Year ◽

Regional Settlement

In Part I of this report the results are given from 43 months of measurements of forces and bending moments on two instrumented precast piles driven through 40 m (130 ft) of soft clay and 15 m (50 ft) into underlying silt and sand. The force in the piles increased due to negative skin friction. After the first 5 months a force of nearly 40 tons was observed at the bottom of the clay layer. During this time the reconsolidation of the clay after the driving took place. The force due to the reconsolidation effect amounted to about 30 tons, while the rest was due mainly to negative skin friction caused by a small regional settlement. The latter force increased linearly with time by about 15 tons per year. Seventeen months after the driving the pile heads were loaded with 44 tons and one year later another 36 tons were added. The load on the pile head eliminated the negative skin friction, which however started to return with the continued regional settlements.In Part II of the report general design formulae for piles considering negative skin friction are given. The formulae should be used to check that the permanent and transient working loads, which have been chosen according to ordinary design rules, are not too large when negative skin friction develops.When settlements due to negative skin friction are not acceptable, the negative friction can be reduced by applying a thin coat of bitumen to the piles. References are made to investigations concerning reduction of skin friction, and practical difficulties are pointed out.

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STUDY ON THE USE OF SWELLING PAINT AS A MEASURE TO REDUCE NEGATIVE SKIN FRICTION : Part 1 Material characteristics

Journal of Structural and Construction Engineering (Transactions of AIJ) ◽

10.3130/aijsx.443.0_87 ◽

1993 ◽

Vol 443 (0) ◽

pp. 87-94

Author(s):

Kazuhiro KAWABE ◽

Akira ENAMI

Keyword(s):

Skin Friction ◽

Negative Skin Friction ◽

Material Characteristics

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Downdrag Measurements on a 160-Ft Floating Pipe Test Pile in Marine Clay

Canadian Geotechnical Journal ◽

10.1139/t72-014 ◽

1972 ◽

Vol 9 (2) ◽

pp. 127-136 ◽

Cited By ~ 28

Author(s):

M. Bozozuk

Keyword(s):

Skin Friction ◽

Compressive Load ◽

Marine Clay ◽

Positive Skin ◽

Negative Skin Friction ◽

Pore Pressures ◽

Excess Pore Pressures ◽

Test Pile ◽

Excess Pore

Large negative skin friction loads were observed on a 160 ft (49 m) steel pipe test pile floating in marine clay. The test pile was driven, open-ended, on the centerline of a 30 ft (9 m) high granular approach fill on the Quebec Autoroute near Berthierville. Since the installation was made in 1966 the fill has settled 21 in. (53 cm), dragging the pile down with it. Negative skin friction acting along the upper surface of the pile was resisted by positive skin friction acting along the lower end as it penetrated the underlying clay. Under these conditions the pile compressed about [Formula: see text] (2 cm). Analysis of the axial strains indicated that a peak compressive load of 140 t developed at the inflection point between negative and positive skin friction 73 ft (22 m) below the top of the pile. Negative and positive skin friction acting on the upper surface of the pile exceeded the in situ shear strength and approached the drained strength of the soil where excess pore water pressures had dissipated. At the lower end where the positive excess pore pressures were high and relative movement between the pile and the soil was large, the positive skin friction approached the remoulded strength as measured with the field vane. Skin friction was increasing, however, as positive escess pore pressures dissipated.This paper shows that skin friction loads are related to the combination of (a) in situ horizontal effective stresses, (b) horizontal stresses due to embankment loads, and (c) horizontal stresses due to differential settlement of the fill.

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