Effect of water content on clogging of dredged slurry under vacuum preloading from PIV perspective

Abstract

Vacuum preloading combined with prefabricated vertical drains is a widely used system for improving soft clay-dredged slurry deposits. However, the influence of the initial water content on clogging is not yet fully understood. In this study, laboratory model tests were conducted on slurry with initial water contents of 106%, 133%, and 159% during vacuum preloading. The process of vacuum preloading was monitored from the perspectives of discharged water volume, pore water pressure, as well as the displacement and strain profile of soil patches by using the novel particle image velocimetry (PIV) technique. The results showed that the clogging formation process could be divided into three stages based on the water discharge rate: rapid formation, transition, and slow formation. An increase in initial water content resulted in a larger horizontal displacement, leading to a thinner and denser clogging zone with lower permeability coefficients and a reduced rate of pore pressure dissipation. Empirical equations for the thickness of the clogging zone versus time were proposed using the PIV technique, providing a reference for theoretical consolidation calculations and making the calculations more practical by considering the variation of the clogging zone during vacuum preloading.

Keywords:

• Vacuum preloading
• dredged slurry
• initial water content
• clogging
• particle image velocimetry (PIV)

Acknowledgment

The work described in this article was supported by the National Natural Science Foundation of China (Grant Nos. 42007236, 52078464, 51879234, 51978621, U2006225), Natural Science Foundation of Zhejiang Province (Grant No. LTZ21E080001), and European Union’s Horizon 2020 Framework programme Marie Skodowska-Curie Individual Fellowships under grant agreement (Grant No. 101025312). The authors are very grateful for the above support.

Data availability statement

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Disclosure statement

We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service, and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “PIV-based comparison of the clogging formation during vacuum preloading with different water content dredged slurry.”

Additional information

Funding

The work described in this article was supported by the National Natural Science Foundation of China (Grant Nos. 42007236, 52078464, 51879234, 51978621, U2006225), Natural Science Foundation of Zhejiang Province (Grant No. LTZ21E080001), and European Union’s Horizon 2020 Framework programme Marie Skodowska-Curie Individual Fellowships under grant agreement (Grant No. 101025312). The authors are very grateful for the above support.