عبدالرضا فاضلی

One type of problematic soil in geology and geotechnical engineering recognized as collapsible soils can withstand relatively high pressure in an unsaturated state. The constant stresses because of soil saturation leading to a large volume reduction in the partially saturated condition are a matter of issue for the infrastructures constructed in the regions containing these soil types. As one of the environmentally friendly materials and potential stabilizers, nano-silica can be used to treat collapsible soils. The present study investigates the nano-silica effect on the soil collapse treatment in the Sivand region, Fars Province, Iran. A set of laboratory tests, including grain size analysis, Atterberg limits tests, water content, sand equivalent test, proctor and modified proctor tests, normal and double consolidation tests, were performed to determine the soil sample’s geotechnical characteristics. The consolidation test was then carried out on soil samples without nano-clays, reconstructed with 11% moisture content using static compaction methods to show the increasing nano-silica additive from 1 to %5 will obtain the less collapse index. The tests have also done on samples made using the mixture of soil, and nano-silica indicated the swelling of samples after saturation. Test results have shown that the saturation pressure and nano-silica content have direct and indirect relations with the strain of collapsible soils. The extracted test results are used as a database to develop an efficient model to predict reconstructed samples’ strain. Additionally, the parametric and sensitivity analyses confirm the model output with the test results.