Document Type

Article

Publication Date

8-1-2020

Abstract

Physical properties of MICP-treated sands are controlled by CaCO3 distributions in pore space, which remain relatively unexplored. CaCO3 can deposit at the particles' contact area (contact-cementing), coat sand particles (grain-coating), or create a cementation bridge between soil grains (matrix-supporting). The objectives of this paper are to determine the dominant CaCO3 distributions in pore space and investigate the effects of CaCO3 distributions on the small-strain stiffness (measured by S-and P-wave velocities) and permeability of MICP-treated sands. To achieve these objectives, cemented-sand and uncemented-sand models combined with three ideal CaCO3 distributions (contact-cementing, grain-coating, and matrix-supporting) were used to estimate the S-and P-wave velocities. In order to determine the dominant CaCO3 distributions in pore space, the calculated values from the models were then compared with experimental data. It was concluded that the dominant CaCO3 distributions were a combination of grain-coating and matrix-supporting. The effects of CaCO3 distributions at pore space on the variation of permeability were estimated using Kozeny-Carman and Panda-Lake models with three pore-scale cement distributions (pore-lining, pore-filling, and pore-bridging). The comparison between laboratory-measured and calculated permeability from the pore-filling Panda-Lake model for seven types of sands demonstrated a relatively good match with a maximum difference of one order of magnitude. The comparison suggests the pore-filling Panda-Lake model can be used for estimating the permeability of the MICP-treated sands. (C) 2020 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Societ

Publication Source (Journal or Book title)

SOILS AND FOUNDATIONS

First Page

944

Last Page

961

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