scholarly journals AN ANALYTICAL STUDY OF SINGLE PILE DUE TO PILE HEAD LOAD AND NEGATIVE SKIN FRICTION

1999 ◽  
Vol 64 (519) ◽  
pp. 63-69
Author(s):  
Tsutomu TSUCHIYA ◽  
Kiwako DOBASHI
Keyword(s):  
Skin Friction ◽  
Analytical Study ◽  
Single Pile ◽  
Pile Head ◽  
Negative Skin Friction

Finite element analyses of negative skin friction on a single pile

2012 ◽  
Vol 7 (3) ◽  
pp. 239-252 ◽  
Author(s):  
Jinyuan Liu ◽  
Hongmei Gao ◽  
Hanlong Liu
Keyword(s):  
Finite Element ◽  
Skin Friction ◽  
Single Pile ◽  
Finite Element Analyses ◽  
Negative Skin Friction

Field Tests and Numerical Simulation of Pile Head Load Influences on Negative Skin Friction Behaviors of Piles

2011 ◽  
Vol 261-263 ◽  
pp. 1099-1103
Author(s):  
Li Nong Xia ◽  
Yun Dong Miao ◽  
Xin Tong ◽  
Shun Li
Keyword(s):  
Numerical Simulation ◽  
Skin Friction ◽  
Field Test ◽  
Axial Force ◽  
Field Tests ◽  
Neutral Position ◽  
Test Results ◽  
Pile Head ◽  
Negative Skin Friction ◽  
Load Increase

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.

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

1972 ◽  
Vol 9 (4) ◽  
pp. 323-337 ◽  
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.

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

1972 ◽  
Vol 9 (2) ◽  
pp. 127-136 ◽  
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.

Reduction of pile head displacement for restrained-head single pile

2009 ◽  
Vol 13 (3) ◽  
pp. 143-152 ◽  
Author(s):  
Jinoh Won ◽  
Fred H. Kulhawy
Keyword(s):  
Single Pile ◽  
Pile Head ◽  
Head Displacement
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