چكيده به لاتين
A review of the technical literature related to salty soils and the deep mixing method shows that despite the high use of the deep mixing method and the high application of this method in saline soils and coastal areas, a special study is not investigated on the improvement of salty soils using the deep mixing method. Therefore, this research investigates this issue. In order to do this research, first, a deep-mixing device was prepared at the laboratory scale and some of its parts were modified. Then required materials such as silica fume, type II cement, 131 Firoozkooh sand and super plasticizer was prepared. In the next step, by selecting a density of 70% for sand, three different percent for salt (5, 10 and 20), three different percent for silica fume (10, 15 and 20), and three ages 7, 14 and 28 for specimens, a total of 150 specimens with a mean diameter of 9 cm is made inside the chamber and then, by testing the unconfined compressive strength of columns, the compressive strength and the modulus of elasticity values of the specimens are obtained. After that, the results have been analyzed, which shows that, with increasing salt content, the compressive strength and modulus of elasticity have decreased, and with increasing the amount of silica fume, the compressive strength and modulus of elasticity of the specimens have also increased, with an optimum of 15% for silica fume, which has the highest compressive strength And modulus of elasticity among the specimens. Then, using compressive strength and modulus of elasticity values and using XLSTAT software, a relationship is prepared to predict the compressive strength and modulus of elasticity.
The results show that by increasing salt content in the soil, the resistance of the samples decreased and the amount of the modulus also decreased. The amount of resistance and modulus of elasticity increased by adding 15% silica fume to cement grout and then decreased.
