Speaker
Description
One of the most economical and viable methods of soil improvement is dynamic compaction. However, dynamic compaction can only be applied on deposits where the degree of saturation is low and the permeability of the soil mass is high to allow for good drainage. The technique does not work very well on soils having a large content of fines. Also dynamic compaction produces lateral ground vibrations which can travel far from the construction site, which can discomfort the people living close to these areas. The current research aims to develop a new technology to desaturate saturated soils using the process of MIDP – Microbially Induced Desaturation and Precipitation through nitrate reduction, which extend the use of dynamic compaction as a ground improvement technique to saturated soil conditions and soils with higher fines content. To evaluate the feasibility of this technology an experimental program has been performed, in which soil columns have been treated with MIDP. In this process, indigenous micro-organisms are stimulated to convert nitrate into nitrogen gas, which desaturates the soil. After the process has finished, dynamic loading is applied to the soil columns. During the MIDP process and during the dynamic loading, the deformation and pore pressures area measured for various amounts of compactive effort and compared with the non-treated soil. Based on the experimental results the feasibility of the proposed technology is discussed.
References
O’Donnell S., Rittmann B.E. & Kavazanjian E. (2017). “MIDP: Liquefaction Mitigation via Microbial Denitrification as a Two-Stage Process. I: Desaturation.” J. Geotechnical and Geoenvironmental Engineering, 143 (12)
Pham, V. P., Nakano, A., Van der Star, W.R.L. Heimovaara, T.J. & Van Paassen L.A. (2016). "Applying MICP by denitrification in soils: a process analysis." Environmental Geotechnics: 1-15, in press.10.1680/jenge.15.00078
Pham, V. P. (2017), Bio-based Ground Improvement through Microbial Induced Desaturation and Precipitation (MIDP), PhD thesis, Technical University Delft.
Van Paassen, L. A., Daza, C. M., Staal, M., Sorokin, D. Y., Van Der Zon, W. H. and Van Loosdrecht, M. C. M. (2010), ‘Potential soil reinforcement by biological denitrification’, Ecological Engineering 36(2), 168–175.
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