EFFECT OF SOIL DENSITY AND PLUG CHARACTERISTICS ON BEHAVIOR OF SINGLE PIPE PILE EMBEDDED IN COHESIONLESS SOIL AND SUBJECTED TO UPLIFT FORCE

Hanaa S Hamadi,Husain A Abdul-Husain

doi:10.30572/2018/kje/120301

Abstract

It is a significant issue to analyze and understand the pile’s behavior as well as to predict the piles’ capacity exposed to uplifting load when designing a foundation. Experimental model tests have been conducted for a single pile embedded in cohesionless soil and subjected to uplift force. The experimental tests were performed using open-ended steel pipe piles with circular cross-sectional area an outer diameter of 50 mm in steel soil box (0.5*0.5) with four different height (0.30, 0.50 and two with 0.40 m). The tested piles have been embedment with penetration ratios (PR=L/D) of 10. Three different densities (25%, 50% and 75%) have been used to perform the tests. In addition three tests have been made with relative density of 50% to investigate the function the developed soil column inside the pile (soil plug) during installation. The results revealed that the behavior of single piles depends mainly on soil density and the ultimate pull-out capacity of the pile increases with the increasing of the soil relative density and used the data from this tests to presented formula to estimate the IFR and takes the soil state parameter as a qualitative variable. The results showed also that the removing of plugging soil decreases the pile’s pull-out capacity by about 85%. Whilst, using of closed-end or filled with concrete give higher capacity than that of open-end pipe pile by about 33% and 87% respectively.

Highlights

Pile foundations are often used to transmit the loads superstructure to the strong soil layer(s) if the subsurface soil is of inadequate strength
Studying the behavior of piles under uplift forces as well as the parameters affecting the uplift capacity of piles is one of the most important and interesting areas of research in geotechnical engineering, when that related with the soil effect
The present study aims to examine the effect of soil state on the pull-out piles capacity as well as formation of soil’s plugging and make statistical analysis and suggest regression models IFR which have been investigated experimentally

Summary

INTRODUCTION

Pile foundations are often used to transmit the loads superstructure to the strong soil layer(s) if the subsurface soil is of inadequate strength. Studying the behavior of piles under uplift forces as well as the parameters affecting the uplift capacity of piles is one of the most important and interesting areas of research in geotechnical engineering, when that related with the soil effect. The applied uplift load is resisted by the sum of shaft resistance developed between the pile and the soil, soil plug capacity inside the pile and its weight. A new method to predict the behavior of pile-soil interaction under axial tension forces in sand soil and load against displacement curve presented by Aser et al, (2017). As it is known, full-scale field tests is much better in terms of results, but it is costly and difficult to perform. Study the plug condition influence upon the piles capability to resist pull-out load

ULTIMATE CAPACITY OF PILE

MATERIALS AND EXPERIMENTAL MODEL

STEEL BOX

Findings

OF RESULTS

CONCLUSIONS