International Journal of Scientific & Engineering Research, Volume 7, Issue 12, December-2016 546 ISSN 2229-5518 IJSER © 2016 http://www.ijser.org The Study Based on Collapsible Soils and Their Collapse Potentials in Semnan Desert Area in Iran Siamak Boudaghpour Abstract— Collapsible-soils are numbered among problematic soils in nature that under similar tension and by increasing the ratio of humidity show very high amount of volume shortage. This volume shortage causes smashes in soil’s structure and finally causes considerable settlements. The existence of these kinds of soils necessitates more and more consideration and examination of Collapsible-soils behaviors and properties. It’s obvious that without considering the Collapsible-soils properties before they are under construction, it can cause irreparable damages. In present research in order to recognition of Collapsible-soils in Semnan deserted province and examination of their collapse potential, 32 points with fine grains soil layers and Aeolian soil have been studied and the relation between the factors in Collapse such as the ratio of humidity and Dry specific weight and so on, with the amount of collapse potential have been studied. In order to evaluate the collapse potential, after the classification of the provided samples of studied points Double consolidated test have been done on undisturbed samples. The results of the tests that have been done, indicate that the samples which belong to 20 points that nearly 85% of them are ML and CL-ML, have got Collapse potential with weak to hard ratio. According to research achievements the majority part of Collapsible soils are located and accumulated in south west of Semnan province. Index Terms—Submission; Collapsible soil; Collapsial Assesment ; Collapsible Potentials; Semnan desert area;Soil Density; Double consolidation ——————————  —————————— 1 Introduction S emnan province is a deserted area located in central part of Iran affected with warm and dry air flows. As compare to researches done in different parts of the world an urgent need of the study of Collapsible soils properties in Iran becomes apparent to be more applicable. In this study geotechnical properties and Geotechnical dangers of collapsible-soils, effective factors on collapse and the methods of reparation and improvement of collapsible soils have been examined. Collapsible soils are different in admixtures, mechanical physical properties and the depth of fallen hill and deformation of repose. Generally these soils are recognized by low moisture, high porosity and repose/collapse ability layers. Collapsible soils are able to bear considerable load. But as soon as the moisture content increases the gap between particles can decreased considerably. In addition to the reduction of bearing capacity appears. Smashes are created in soil’s structure that causes considerable settlements. According to present study the main properties which cause soils to show collapsible specifications themselves are high porosity (>40%), Low saturation ratio (<60%), high amount of Silt (>30%-90%), quick softening subject to water, low specific weight) 11- 14 Kn/m3),PI<25 and LL<45. IJSER