Investigation of hydraulic effect in terms of colloid formation from compacted bentonite
Abstract
A series of experiments were conducted an investigation into the amount of erosion, size of eroded particles, and swelling area of physically purified and compacted bentonite under different flow rates. Dynamic light scattering method(DLS) was used to determine the size and amount of eroded particles and Autocad programme was used to determine the swelling area.Where compacted bentonite and crushed granite come into contact, groundwater plays an important role in the erosion of bentonite.Contact of compacted bentonite with water, its saturation with water and its subsequent swelling and entry into the voids around it are the primary steps for the formation of colloid particles. Factors affecting the erosion of compacted bentonite are groundwater flow rate, ionic strength of the water contacting the bentonite, pH of the water, etc. The groundwater to which the compacted bentonite buffer will be exposed during the designed service life of the compacted bentonite buffer reduces the robustness of the bentonite buffer.Erosion of compacted bentonite not only affects its physical stability but also causes the transport of radionuclides it absorbs.An experimental methodology is presented. The experimental results showed that with increasing flow rate the amount of eroded bentonite increases and the swelling area increases. No correlation was found between the flow rate and the size of the eroded particles.
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References
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