Performance of Under-Reamed Piles in Collapsible Soil

One of the Iraqi geotechnical problems is presence gypseous soils covering about (27-36) percentage Iraq containing gypsum between (10-70) ratios. The main reason for soil problematic dissolution when these are inundated. However, soluble can be leached out particles, so led to cracking, tilting, and collapsing related structure changing properties. aim this work investigate performance under-reamed piles as a new, improved method reduce moisture sensitive primary triggering mechanism volume reduction collapsible soil, which considered non-elastic deformation; was done by carrying series inundation with using different types under reamed arrive best suitable type useful in soils. reams concrete one or more ream, weak where sizable ground movement, variations, filed up ground, silty clay, loose sand has advantage increase strength. This paper includes experimental model static load simulated steel plate on pile cap, then load-settlement curve, friction force, bearing force founded from investigation patterns reamed. It found that number bulbs had significant settlement reach 93% case triple greatest results comparison other reference uniform cross-section wet state.