Lime Migration in Pond Ash Deposits Stabilized by Hydrated Lime Columns


Sudeep Kumar Chand

Asst. Professor, Dept. of Civil Engg., Indira Gandhi Institute of Technology, Sarang- Orissa, India

Chillara Subbarao

Former Professor, Dept. of Civil Engg., Indian Institute of Technology, Kharagpur, West Bengal, India


A method is proposed for in-place stabilization of abandoned ash pond sites by hydrated lime columns. Migration of lime from the lime column through the ash bed is central to the process. The present study reports the experimental findings of such in-place lime column stabilization technique applied to large-scale laboratory models of ash ponds. The rate of lime migration through ash bed is studied taking pH as the indicator. Samples from different radial distances and different depths of the ash bed were collected at different time intervals and pH measurements were made to establish effective migration of lime from the central lime column. This is also substantiated by the results of unconfined compressive strength and hydraulic conductivity tests conducted on ash samples at various locations and depths after long term in-place lime stabilization.

Keywords: over-consolidation, clay, fine sand, oedometer test.

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