A sustainable methodology to ameliorate stabilization of fine-grained soils
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Date
2021-01
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
In the past few decades there have been a tremendous increase in Civil Engineering activities like construction of buildings, roads, highway and airfields. But, there is inadequacy of appropriate land for such activities because, frequently the soil available at these sites may be clayey, loamy or black cotton soil which have posed complexities to the Geotechnical engineers. As, such soils reflect different types of volumetric changes when acted as supported material below foundations. So, many researchers try to find solution to overcome this issue. And one such economic solution is soil stabilization i.e. to enhance the soil properties by introducing different additives in it. Initially, introduction of sand to soils followed by compaction was one of the common practices
adopted by engineers for stabilization of such weak soil deposits. But, competent substitute for sand becomes necessary with time, as the application of sand is not only limited to geotechnical applications but also in construction industry (Chetia.M. et al. 2018). So, many researchers after doing their critical evaluation and comparison suggest stone dust to be a competent substitute for sand. Stone dust possesses both pozolanic as well as coarser particles in it. These characteristics of stone dust make it an appropriate
admixture in fine grained soils in order to achieve desirable strength. Stone dust is a solid waste that is produced every year to a generous extent of 200 million tonnes per annum. It is a waste that cannot be treated before it is dumped which therefore creates environmental problems. Therefore, utilization of these wastes becomes obligatory. With the advancement in technology,
researchers utilize these wastes to ameliorate the geotechnical properties of soil to make it suitable for construction activities.
Over the past several decades, many investigators have devoted considerable efforts to study the suitability of stone dust as additive to modify the geotechnical properties of weak soil deposits. Extensive investigations and testing programmes have been conducted by them to study the strength and compaction characteristics, index properties, consistency when stone dust is used as an additive in weak soils. However, the review of literature has revealed that only a limited study has been done on shear strength properties and permeability. In view of the above, the main objective of this paper is to investigate the effect of stone dust (introducing in varying percentages) on shear strength and permeability characteristics of clayey soil. In addition, laboratory experiments like consistency limit tests, compaction test, unconfined compression test and CBR tests are also performed with an objective to reach for better results and conclusions. In order to fulfil our objective, a comprehensive investigation of using stone dust as additive has been planned. Firstly, stone dust was procured from Pal stone industries Limited located at Lalkuan,
Uttarakhand. Soil was acquired from the campus of G.B. Pant University of Agriculture & Technology, Pantnagar (Uttarakhand). The overall testing programme was conducted in three phases. In the first phase experimental investigation of soil was carried out. In the second phase laboratory examinations was done on stone dust. In the third and last phase soil was mixed with different percentages of stone dust (i.e. 0%, 10%, 20%, 30%, 40% and 50%). By analyzing the results obtained from various laboratory experiments, it was concluded that utilization of stone dust as additive is satisfactory when mixed with clayey soil. Plasticity index was observed to decrease from 12.81% to 2.11% with increment in percentage of stone dust from 0 to 40% and beyond this a non plastic behaviour of soil was observed. Proctor results reflect that optimum dry density was decreased from 16.75% to 13.25% while maximum dry density increases from 1.74g/cm3 to 1.89g/cm3 on increasing the stone dust percentage from 0 to 50%. The stress at failure and CBR increased up to 30% addition of stone dust and afterwards they show a decreasing trend. The value of cohesion decreases while angle of internal friction increases. The permeability of samples was increased when stone dust was mixed up to 50%. These results were compared with the previous study’s results done by many researchers which reveal a fairly good agreement between the observations.