scholarly journals Model study of screw pile installation impact on ground disturbance and vertical bearing behaviour in dense sand

2021 ◽  
Vol 710 (1) ◽  
pp. 012056
Author(s):  
Muhammad Azhar Saleem ◽  
Adnan Anwar Malik ◽  
Jiro Kuwano
Keyword(s):  
Dense Sand ◽  
Pile Installation ◽  
Screw Pile ◽  
Model Study ◽  
Vertical Bearing

scholarly journals Model Study of a Single Pile With Varied Configuration in Sand

2021 ◽  
Author(s):  
Mohamed A. Sakr ◽  
Waseim R. Azzam ◽  
Hatem K. Kassim
Keyword(s):  
Load Capacity ◽  
Soil Conditions ◽  
Single Pile ◽  
Axial Loads ◽  
Cross Sectional ◽  
Dense Sand ◽  
Compression Load ◽  
Pile Installation ◽  
Model Study ◽  
Pile Length

Abstract In this experimental work, the influence of pile cross-section with varied configurations on the axial compression load capacity of a single pile and related settlement in sand are investigated. The influence of relative sand density (Dr), the pile length to diameter (L/D) ratios and the pile installation techniques are presented. A testing program comprising seven model steel piles with varied shapes of 20 mm width/diameter was conducted. The tests are performed on model piles with the pile length to diameter ratios of 10 and 30 installed in the three cases of sand modeling as loose, medium dense and dense sand. Results indicated that, the rectangular pile is the optimization cross-sectional under the same pile geometry and soil conditions. Also, the increase of the relative sand density has a significant influence on the ultimate compression pile load. Furthermore, the ultimate axial loads of flexible piles in the case of loose sand using the non-displacement method were found to be increased by 119%, 114%, 143%, 82% 139%, 89% and 100% comparing with the ultimate axial loads of rigid piles for the seven models of closed-ended pipe, open-ended pipe, conical base pipe, square closed-ended, square open-ended, tapered and rectangular piles respectively. While, these percentages were found to be increased by (49%, 37%, 26%, 78%, 35%, 71% and 91%) and (77%, 50%, 13%, 116%, 61%, 89% and 85%) in the cases of medium dense and dense sand respectively. The results also indicated that, piles installed in sand using jacking technique have more resistance compared with piles installed in sand using non-displacement technique.

Negative skin friction from surface settlement measurements in model group tests

1995 ◽  
Vol 32 (6) ◽  
pp. 1075-1079 ◽  
Author(s):  
Mehmet Ufuk Ergun ◽  
Devrim Sönmez
Keyword(s):  
Soft Clay ◽  
Soil Surface ◽  
Pile Group ◽  
Friction Model ◽  
Model Group ◽  
Pile Groups ◽  
Negative Skin Friction ◽  
Dense Sand ◽  
Model Study ◽  
Negative Friction

Groups of model wood piles driven to end bearing through dense sand over soft clay were used to determine the relative settlement of the soil surface inside and outside the groups as the soil was compressed by air pressure. Square 30 mm piles at spacings of 2 to 6 times the pile width were used in groups of 3 × 3, 4 × 4, and 5 × 5. The results indicate that pile group effects were negligible at pile spacings at 5 to 6 pile widths. Key words : negative friction, model study, pile groups, sand.

The Vertical Bearing Capacity Analysis of Screw Pile in Clay

2013 ◽  
Vol 788 ◽  
pp. 575-577
Author(s):  
Yu Cui ◽  
Jun Qiang Wu
Keyword(s):  
Bearing Capacity ◽  
Good Choice ◽  
Key Factors ◽  
Ocean Energy ◽  
Offshore Engineering ◽  
Screw Pile ◽  
New Type ◽  
Vertical Bearing ◽  
Energy Gains ◽  
Vertical Bearing Capacity

Recently,ocean energy, especially wind energy, gains attention from all over the world.In offshore engineering , the design and construction of foundation are key factors. As a new type of piles, screw pile has advantages of compressive capacity and uplift capacity.Therefore, screw pile is a good choice for offshore engineering foundation. In this paper , ABAQUS software analysed vertical bearing capacity of screw pile and steel pile with same diameter in clay .And the analysis result shows : the compressive resistance and uplift resistance of screw pile are 1104KN and 974.3KN, the same capacity of steel pile are only 332.3KN and 189.7KN.

Centrifuge Study of the Effects of Lattice Leg on Penetration Resistance and Bearing Behavior of Spudcan Foundations in NC Clay

2012 ◽  
Author(s):  
Yu Ping Li ◽  
Fook Hou Lee ◽  
Siang Huat Goh ◽  
Jiang Tao Yi ◽  
Xi Ying Zhang
Keyword(s):  
Bearing Capacity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Clay ◽  
Penetration Resistance ◽  
Cavity Depth ◽  
Circular Column ◽  
Model Study ◽  
Vertical Bearing ◽  
Vertical Bearing Capacity

This paper reports the primary results of a centrifuge model study into the possible effects of the lattice leg on the penetration resistance and vertical bearing capacity of spudcan foundations in normally consolidated clay. Up to now, the possible effects of the lattice leg has been largely ignored in both research and design of spudcan foundation. Centrifuge experimental results show that there is an increase in penetration resistance for spudcan footing equipped with lattice leg, in comparison with spudcan footing connected to slender circular column leg as widely used by current research. Larger excess pore water pressure was generated by the spudcan penetration with lattice leg in compare with that without. Moreover, the presence of the lattice leg is shown to affect the cavity depth formed around the penetrated spudcan footing, which is simply assumed completely back flow for spudcan penetration in soft clay by SNAME (2008). It was found that the bearing capacity of spudcan foundation has been further underestimated by SNAME (2008) due to the neglecting of lattice leg effect. Taken altogether, this implies that changes in penetration resistance arising from the lattice leg may be due to the effect of the latter on the backflow pattern. Apart from highlighting the effect of the sleeve with big openings, the results also highlight the possible future use of sleeves to enhance the bearing capacity and possibly reduce the penetration of spudcan foundations in various soil deposits.

Full-Scale Site Investigations on Soil-Plugging Inside Tubular Piles

2012 ◽  
Author(s):  
Sascha Henke
Keyword(s):  
Soil Column ◽  
Present Contribution ◽  
Factors Affecting ◽  
Pile Installation ◽  
Site Investigations ◽  
Pile Diameter ◽  
External Stresses ◽  
Vertical Bearing ◽  
The One ◽  
Analytical Approaches

Soil-plugging inside open-ended piles is a well-known phenomenon which increases vertical bearing capacity on the one hand but also leads to increasing driving resistance. There are many different factors affecting the tendency of soil-plug formation like pile diameter, geometry of the pile, installation method, soil density and so on. In the present contribution, in-situ measurements regarding two tubular piles with a diameter of 71 cm are presented. The piles are first vibratory driven up to 6.5 m penetration and afterwards they are impact driven to their final penetration depth. During the installation internal and external stresses at the pile toe and accelerations and strains at the pile head are measured on both piles. Furthermore, one pile is equipped with a cone penetrometer inside the pile to monitor cone and shaft resistance during the installation. At the end of the installation the height of the internal soil column is measured. The results are discussed with focus on the installation method on soil plugging tendency. Concluding they are compared to classical analytical approaches.

Bearing capacity mechanisms for pipes buried in sand

2020 ◽  
Author(s):  
Jinbiao Wu ◽  
George P. Kouretzis ◽  
Laxmi Prasad Suwal
Keyword(s):  
Bearing Capacity ◽  
Friction Angle ◽  
Flow Rule ◽  
Loose Sand ◽  
Buried Pipelines ◽  
Buried Pipes ◽  
Dense Sand ◽  
Physical Model Tests ◽  
Vertical Bearing ◽  
Sand Material

This paper presents results of scaled physical model tests performed to measure the reaction developing on a rigid pipe buried in dry sand, when the pipe is subjected to vertical downwards movement relative to its surrounding soil. The aim of this experimental study is to evaluate the efficacy of methods used to determine the properties of vertical bearing springs, an integral part of beam-on-nonlinear Winkler spring models used for the analysis of buried pipelines subjected to permanent ground displacements. We show that bearing capacity formulas used in practice to estimate the ultimate reaction developing on buried pipes may provide reasonably accurate estimates, provided that they are used together with sand friction angle values that account for the fact that granular materials do not obey an associative flow rule, and with bearing capacity factors compatible with the mode of sand failure observed in the tests. We also provide evidence suggesting that laying pipes in loose sand backfills does not have a beneficial effect on the reaction developing on the pipe, compared to medium dense sand, and we recommend against using loose sand material properties for the estimation of the properties of vertical bearing springs.

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