Open AccessAn experimental study of the load carrying capacity of straight shaft and underreamed piles in expansive soil
Author(s) -
Hayder M. Ziyara,
Bushra S. Albusoda
Publication year - 2021
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/1067/1/012050
Subject(s) - expansive clay , pile , geotechnical engineering , water content , saturation (graph theory) , expansive , bulb , soil water , carrying capacity , clay soil , ultimate load , bearing capacity , field capacity , moisture , wet bulb temperature , geology , environmental science , materials science , engineering , soil science , structural engineering , mathematics , composite material , horticulture , humidity , compressive strength , finite element method , ecology , biology , combinatorics , thermodynamics , physics
This research aimed to determine and evaluate the load carrying capacity of underreamed piles embedded in expansive soils. Eight models of concrete piles were developed to examine the influence of piles’ bulb number and length on ultimate load carrying capacity. The piles used in this work had 20 mm stem diameters and 40 mm bulb diameters, and multi-layer soils (expansive soil above dense sand) were used. The piles used in the experiments were divided into two groups, each with four piles. The first group with l/d=14 had all piles embedded in the expansive soil layer and the pile’s tip set on dense sand while the other group, with l/d=24, had the pile stems embedded in the expansive soil and all bulbs in the dense sand. Experiments were then done under two conditions: optimum moisture content and soil completely saturated with water, with results that showed that the percentage of ultimate load carrying capacity increased in proportion to the l/d ratio on adding one bulb to a straight shaft pile and then increased slowly for piles with 2 or 3 bulbs in saturation conditions. The percentage of ultimate load carrying capacity increased similarly in optimum moisture content conditions. The results also showed a decrease in ultimate load carrying capacity between the two conditions of tests for piles with the same l/d and the same number of bulbs, however.