عنوان مقاله [English]
Iran is a country with unstable soil. If soil classes, characteristics and structures are not identified properly, railroads or roads that are to be built can face significant problems, as the soil becomes saturated. Some soils in our environment cannot undergo the normal tension they encounter, and by the slightest increase in the ratio of humidity, will encounter high settlement. These kinds of soil, mainly found in hot and dry regions, like deserts, are called collapsible soils. In this article, to correct the soil of these regions, some items, like the behavior of lime injected materials in the presence of clay in cementitous soil, for creating suitable adhesion among grains and micro-silica as porosity filling materials, are studied separately.In this study, to investigate and stabilize soil, reduce collapse potential and increase its strength properties, the use of limestone injection technology has been considered. Then, the collapse potential of the soil under injection has been compared with that of natural state soil. The results indicate the good performance of the injection method compared with existing methods. These results show that the injection of lime will reduce the potential for soil collapse. The soil shear strength parameters improved after injection, and the value of $phi_u$ after injection reached an amount of approximately 2.15 times the initial internal friction angle. Parameter $phi$ increased up to 1.62, which, considering the fixed amount of tension in both tests on soil in normal state, and the injected soil, was associated with an increase in internal friction and a reduction in the adhesion of soil grains. The results of field and laboratory tests reveal that according to clay cementation among soil grains on site, the injection of lime would result in a considerable reduction in the collapsibility potential of soil in a saturated condition. Therefore, it can be suggested as a suitable solution.