Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : soil plug

Comparative Study of Bearing Loads for Open Ended Pipe and H-Piles in Sandy Soil

M.A.M. Al-Neami; M.H. Wasmi

Engineering and Technology Journal, 2017, Volume 35, Issue 6, Pages 593-601
DOI: /10.30684/etj.35.6A.6

This paper clarifies the response of steel piles installed in sand under vertical static compression load. To evaluate the ultimate load capacity of both piles, the results were introduced in a comparison form. Pile capacity of open ends pipe pile is affected by degree of soil plugging and sometimes the removal of soil plug may decrease the friction between soil and inner shaft of pile and causes a reduction in the load capacity. Therefore, to avoid plugging phenomenon occurred during piles installation; H-piles sections are manufactured based on the equivalent area steel of open pipe piles and tested under the same conditions. 36 steel piles with lengths equal to (30, 40, and 50) cm are tested. The piles are embedded using jacking technique in sandy samples with two different relative densities; medium sand (60%) and dense sand (80%).The results showed that H-pile has a load capacity greater than open ended pipe pile and increases with the increase in both length and diameter (width of flange) of pile. When relative density increased, plugging phenomenon does not occur in H-pile therefore, it can be used instead of open-ended pipe pile to get rid of plugging phenomenon problems.

Effect of Particle Size Distribution of Cohesionless Soil and Pile Diameter on the Behavior of Open Ended Pipe Piles

S.J. Abdullah; M.R. Mahmood

Engineering and Technology Journal, 2017, Volume 35, Issue 1A, Pages 83-90
DOI: 10.30684/etj.2017.127314

Pipe piles are normally used in deep foundations to transfer the structure load to stronger layer beneath the ground or to rock formations. More popular applications of pipe piles are marine construction (offshore structures), bridge piers construction and building construction. This research is conducted to study the effect of grain size distribution of cohesionless soil (i.e. fine, medium and coarse sand) on the ultimate load capacity of pipe piles with different diameters under dry and fully saturated state through an experimental model. Also, Degree of soil plugging behaviors for different pipe pile diameters and saturation conditions (i.e. dry, fully saturated conditions) for different particle size distribution was studied. Karbala sand, were used as a natural soil in the present study, it is poorly graded clean sand of rounded particles. The sandy soil is sieved to obtain a fine, medium and coarse graded according to (ASTM D 422-02). The experimental model tests conducted on four open-ended steel pipe piles models with diameters of (25, 30, 35 and 41mm) embedded within different grain size distribution of sand prepared under dry and fully saturated conditions with relative density of 65%. The results shows that, the ultimate load capacity of open-ended pipe piles embedded within medium grain size exerted higher bearing capacity than the other grain size distribution and increased with increasing piles diameters. The increasing values of the ultimate load carrying capacity for different pipe pile diameters under dry conditions are almost greater than that of saturated conditions by about (1.95-2.4) times for fine sand, (2.36-3.04) times for medium sand and (1.62-1.97) times for coarse sand. Furthermore, Plug Length Ratio PLR (which is the proportion of a soil plug length to the pile penetration depth) was measured for different pile diameters, and it was found that the length of soil column increases gradually with the increasing of a piles diameter

Plug Length Developed in Pipe Pile Embedded Within Partially Saturated Cohesionless Soils (Part 1)

Ali M. AL-Gharbawee; Karim H. Ibrahim Al -Helo; Mahmood Rashid Mahmood

Engineering and Technology Journal, 2016, Volume 34, Issue 7, Pages 1335-1346
DOI: 10.30684/etj.34.7A.7

This paper presents an experimental study to investigate the change of plug length for pipe pile under different state of saturation and investigate the effect of number of pipe piles on plug length. The influence of matric suction (i.e., capillary stresses) in unsaturated zone is typically considered on the plug length of pipe piles.
The experimental work consist of testing 20 models of pipe piles, these models divided into 4 different configuration of pipe piles; single pipe pile, group of double pipe piles, group of triple pipe piles and group of six pipe piles. All these models are loaded and tested under three different states; dry condition, fully saturated condition (i.e., matric suction equals to 0 kPa) and unsaturated conditions with three different matric suction values (6, 8 and 10 kPa), which are achieved by predetermined lowering of water table. The relationship between matric suction and depth of ground water table was measured in suction profile set by using three Tensiometers (IRROMETER). The soil, water characteristic curve (SWCC) was estimated by applying fitting methods through the program (Soil Vision).
The results of experimental work demonstrate that the values of plug length decreased with increase in value of matric suction for the same configuration of pipe piles, and the values of plug length decreased with increase in number of pipe piles.