ارزيابي تأثير ذرات نانو رس بر برخي ويژگي‌هاي فيزيكي و مكانيكي خاك‌ها

Effect of nanoclay particles on some physical and mechanical properties of soils

با توجه به محدودیت‌های ناشی از خاك‌ورزی سنتی و لزوم توجه به كشاورزی پایدار، كاربرد روش‌های نوین خاك‌ورزی امری لازم و ضروری است. در این پژوهش به‌منظور بررسی چگونگی و میزان تأثیر ماده نانو رس بر برخی مشخصات فیزیكی و مكانیكی مؤثر در خصوصیات خاك‌ورزی، تیمارهای مختلف كاربرد نانو ذرات رس برای خرد و پودر كردن خاك مورد بررسی قرار گرفته است. بدین ترتیب با در نظر گرفتن سه نوع خاك با بافت مختلف (سبك، متوسط و سنگین) و 2 سطح از ماده نانو رس شامل بدون ماده پلیمری و مقدار یك درصد از ماده نانو رس، به تعداد 6 تیمار در 3 تكرار مورد آزمایش‌های مختلف فیزیكی و مكانیكی شامل دانه‌بندی، حدود آتربرگ، تراكم و سه محوری قرار گرفتند. نتایج نشان داد كه افزودن ذرات نانو رس تأثیری در منحنی دانه‌بندی، حدود آتربرگ و مشخصات تراكمی نداشته است در حالی‌كه كاربرد ذرات نانو رس موجب كاهش زیادی در میانگین مقدار چسبندگی و زاویه اصطكاك داخلی و به عبارت دیگر پارامترهای برشی خاگ گردید. لذا می‌توان نتیجه گرفت افزایش نانو رس موجب كاهش مقاومت برشی گردیده و به تبع آن عملیات خاك‌ورزی در خاك‌های تیمار شده راحت‌تر و با انرژی كمتری صورت می‌گیرد.

Introduction: As a mechanical tillage practices on soil preparation improve soil structure, increase in porosity, better distribution of soil aggregates and eventually modify the physical properties of soil. The use of nano-technology in agricultural science and its application in tillage for improving the physical properties and mechanical issues has grown substantially. Nanotechnology is an appropriate way to reduce soil limitations. However the nanoparticles are very small amounts in soil, due to features such as high surface area, surface charge (appearance) and sometimes porous nano-engineering of physical-chemical properties of soil are affected significantly (Mohammadi & Niazian, 2013). To use of nanomaterials in the territory of a new issue (Taipodia et al., 2011). Small developments on the use of nanoparticles to improve soil quality and land reform have been taken (Theron et al., 2008). Clay soil was used to enhance the compressive strength (Yonekura & Miwa, 1993). Nanosilica particle effects were examined for increasing resistance against penetration and consolidation (Noll et al., 1992). In 2005, these particles were used to increase adhesion and reduce viscosity. It seemed that the adhesion of the particles was depended on Nanosilica (Mohammadi & Niazian, 2013). The use of nanomaterials showed that the increased pH and soil fertility, improved soil physical structure, and reduced mobility, availability and toxicity of heavy metals and other environmental factors and those that will stabilize the soil components and subsides the erosion in the mining pick, (Lal, 2008). In agriculture, the soil conditioner studies have shown that nanoparticles can mine the soil quality by increasing water-holding capacity, increasing silt and clay and improve levels of nutrients, and eliminate toxins, (Liu and Lal, 2012).In this study, the effect on some physical and mechanical properties of soil contain clay gradation, Atterberg limits, specifications compression and shear parameters of soil were investigated. Materials and Methods: The study was done for 2 years at the Research Institute of Agricultural Engineering Soil Dynamics Laboratory in a completely randomized design with three replications. Soil samples were used for different soil textures. Three types of soil texture, light, medium and heavy were considered. Nanoclay has a mineral base and can improve the properties of the soil. Two levels of the nanoclay containing zero and one percent of the nanoclay, 3 to 6 treatments in different physical and mechanical tests were repeated. The test specimens were prepared in triplicate test and physical, mechanical and chemical testing was performed according to ASTM standard on all models. Mesh test samples were performed by sieve and hydrometer methods according to standard ASTM-D422-98. Plastic soil properties were expressed by the Atterberg Limits, measure the ability to absorb water, soil and to a fine particle adhesion amount and type of fine particles in the soil. Psychological testing was performed to determine the extent and the paste according to ASTM-D4318-98 standard. The maximum dry density and optimum moisture content of the soil compaction characteristics are the most important soil properties such as soil density development projects are in operation. In agricultural applications, in particular for tillage, these two factors are of particular importance. In this study, Praktor standard density testing was performed on the different treatments. In this research, not consolidate Undrained (UU) testing methods were used. The stress tests were done at three levels 100, 200 and 300 kPa respectively. Results and Discussion: Adding nanoparticles of clay significant impact on the size of the samples did not curve. As well as to determine the impact of nano-clay soil Plastic characteristics as psychological tests and the paste was treated on the results of these tests for different treatments and repeated ANOVA revealed a significant effect of soil type on soil Plastic characteristics. The type of control or significant influence characteristics Plastic application of nano regard. The optimum moisture content and maximum dry density values of each sample was extracted from the respective curves that their results suggest that addition of nanoclay had a considerable impact on the density profile. It was observed that the use of nanoparticles in soil reduced the average amount of cohesion and internal friction angle was large. This means that the increasing the nanoclay reduces the shear parameters and therefore the shear strength of the soil. This is very important in terms of tillage. Reducing the adhesion of soil particles allows the lumps are crushed with less energy. Conclusions: Based on the results of studies and experiments conducted in this study, the following conclusions can be extracted. - Adding nanoparticles of clay soils affect the grading curve display. - The effect of nanoclay had more psychological impact than the same amount in the dough. - The results showed that the addition of nanoclay had a considerable impact on the density profile. - The use of nanoparticles in soil reduced the average amount of cohesion and internal friction angle is large. - Due to the increase of nano-clay soil, shear strength decreased as a result of the shear parameters.