Department of Engineering,
Ningjun Jiang obtained his Bachelor Degree of Engineering from Southeast Univerity, China in 2011. After undergraduate study, he was a research assistant in Institute of Geotechnical Engineering, Southeast University for one year. With the financial support from CSC-Cambridge International scholarship, he came to University of Cambridge to pursue his PhD degree from October 2012. His supervisor is Prof Kenichi Soga and his research is mainly about the use of microbially induced calcite precipitation in geotechnical and environmental engineering. he is also a member of Queens' College.
The issue of soil erosion remains open so far although it has been an old problem in civil engineering for decades. This question is approached either in large scale, like from the hydrological and geomorphological points of view, or in element scale, like from the perspective of hydraulics. Among different erosion types, internal erosion involves more with civil infrastructures like embankment dams or oil and gas wells. The research about internal erosion control would contribute to the risk mitigation in some civil infrastructure. In this research, internal erosion in embankment earth dams and oil and gas wells are focused in particular.
As an emerging technique in the realm of civil engineering, bio-mediated processes in soil have drawn much attention in the recent decade. Among major processes, microbially induced calcite precipitation (MICP) has been studied extensively in the field of geotechnical and geoenvironmental engineering. It involves the process of calcite precipitation via ureolysis. Formed calcite has a preference to provide particle-to-particle contact cementation. This cementation leads to association/flocculation of soil particles and hence the modification of soil composition. Considering its effectiveness in modifying soil composition, MICP has the potential to reduce the internal erosion in internally unstable soils.
This research addresses the issue of soil internal erosion control by MICP. A fundamental understanding of mechanisms of internal erosion as well as microbiological and geochemical principles is essential for this study.
The objectives of this study are:
(1) to conduct process simulation of internal erosion in element-scaled test in the laboratory;
(2) to optimize MICP treatment regime for internal erosion control;
(3) to investigate the feasibility of MICP treatment in erosion control under different soil and hydraulic conditions;
(4) to conduct physical modelling of mitigation of internal erosion in embankment dams and sand production in oil and gas wells;
(5) to investigate durability and sustainability of MICP treatment in internal erosion control;
(6) to compare MICP with conventional chemical treatment in internal erosion control.
Y.J. Du, N.J. Jiang, S.L. Shen, and F. Jin. (2012). Experimental investigation of influence of acid rain on leaching and hydraulic characteristics of cement-based solidified/stabilized lead contaminated clay. Journal of Hazardous Materials, 225-226: 195-201.
N.J. Jiang, Y.J. Du, S.Y. Liu, C.Y. Li, and W.T. Li. (2013). Leaching and hydraulic performances of solidification/stabilization treated lead contaminated soil under the effect of acid rain. Chinese Journal of Geotechnical Engineering, 35(4): 739-744. (in Chinese)
Y.J. Du, N.J. Jiang, L. Wang, and M.L. Wei. (2012). Strength and microstructure properties of cement-based solidified/stabilized zinc contaminated kaolin. Chinese Journal of Geotechnical Engineering, 34(11): 2114-2120. (in Chinese)
N.J. Jiang, Y.J. Du, C.Y. Li, K.W. Lu, S.Y. Liu, and M.L. Wei. (2012). Effect of acid rain on chemical and hydraulic properties of cement solidified/stabilized lead contaminated marine soft clay. Geotechnical Special Publication No. 225, Proceedings of GeoCongress 2012: State of the Art and Practice in Geotechnical Engineering, Hryciw et al. (Eds.), American Society of Civil Engineers, Oakland, California, USA. 4015-4023.
M.L. Wei, Y.J. Du, and N.J. Jiang. (2012). Compression behavior of zinc contaminated clayey soils solidified with cement. Geotechnical Special Publication No. 225, Proceedings of GeoCongress 2012: State of the Art and Practice in Geotechnical Engineering, Hryciw et al. (Eds.), American Society of Civil Engineers, Oakland, California, USA. 4042-4049.