X-Ray Diffraction Studies Of Some Madhupur Clay Samples Of Savar And Dhaka Of Bangladesh With Especial Emphasis On Clay Minerals

The clay and non-clay minerals have been identified by XRD analysis. The non-clay minerals include quartz, crystobalite, orthoclase, microcline, plagioclase, calcite, siderite and dolomite, and the clay minerals include kaolinite (52.39%), illite (36.39%) and illite-smectite mixed layer minerals (11.21%). Kaolinite is the most dominant component in the clay mineral assemblages. The clay minerals e.g. kaolinite, illite and illite-smectite have influences on the liquid limit, plastic limit and plasticity index. The higher amount of illite and illite-smectite will increase the liquid limit, plastic limit and plasticity index in the soil whereas higher amount of kaolinite would decrease the liquid limit, plastic limit and plasticity index. The higher the amount of illite and illite-smectite in the soil, the higher the activity in that soil. The clay minerals like kaolinite, illite and illite-smectite have marked influences on the shrinkage limit of the soil. The higher the illite-smectite in the soil, the higher the co-efficient of volume change (mV), compression index (CC), and preconsolidation pressure in the soils. The higher amount of kaolinite and illite decrease the co-efficient of volume change (mV), compression index (CC) and preconsolidation pressure. The increase of kaolinite and illite-smectite in the soil decreases coefficient of consolidation. But the increase of illite slightly increases the coefficient of consolidation. Illite influences the coefficient of permeability value less than illite-smectite, but more than kaolinite. Therefore, the clay minerals have significant influences on the geotechnical behaviour of the Madhupur Clay soil of Dhaka and Savar.