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使用机械和化学方法和/或增强材料以增加土壤剪切强度。加强和加强土土工程项目中土壤加强土壤的必要性需要使用新材料和加强。近年来，虽然研究人员使用了新的化学化合物，但是，纳米粒子并未发现它们的适当情况。在这项研究中，我们尝试使用不同添加剂增加土壤剪切强度参数。由于其工程特征，粘土矿物被认为是有问题的土壤。因此，重新夺回它们是必不可少的。在本研究中，已经研究了具有低塑性性能的粘土。土壤剪切强度是与稳定性相关的任何分析的重要因素，包括斜坡稳定性分析。坡稳定性分析用于地球坝和沟槽。在这项研究中，我们尝试增加土壤剪切强度参数，即使用不同添加剂的凝聚系数（c）和内部摩擦角（φ）。 Direct shear test has been used for obtaining shear strength parameters as well as Mohr-Coulomb theory has been utilized for calculating of them. Although direct shear machine has its defects and its accuracy is low in comparison with tri-axial machine, however in this study it has been selected due to its simplicity and cheapness. Since this investigation aims to compare various additives and all tests have been done at same condition by direct shear machine, its deficiencies have been neglected. Additives used in present research include: Nano-silica in various percentage, Micro-silica, cement, lime (Cao) and these materials’ combination with together. The reason to choose Nano-silica is that it is a very active super-pozzolanic additive. This additive increases strength of sample significantly through chemical actions. Using silica in soil stabilization depends on type and size of silica particles so that the more finely the more continuous gradation, so property of being finer leads to decrease pores among particles and results to increase strength while light gradation has been achieved. Silica is one of the most popular materials which play a significant role in cohesion and filling. Results of experiments have shown significant effect of these additives in increase of soil shear strength parameters. The lime leads to modify behavioral features of fine-grained soils containing clay (properties such as swelling, shear strength, water absorption ability and plasticity properties) but it should not be in vicinity of sulphate ions.Since, in this condition, presence of lime not only doesn’t play an effective role but also it results to decrease in strength as well as increase in swelling. With regard to this reason, Calcium sulfate (石膏)的加入，以研究石灰和纳米二氧化硅稳定土的膨胀。纳米二氧化硅在提高土体抗剪强度的同时，也有效地增加了土体的膨胀度。