DOI: 10.15129/029a4e55-00fb-4c9f-bfee-1fa28c92ef9a
title: Data for: "Meter-scale MICP improvement of medium graded very gravelly sands: Lab measurement, transport modelling, mechanical and microstructural analysis"

description: Data consists of: 1) Figure 5 Tracer (a) and bacteria (b) breakthrough curves in 1-D columns under different velocities (i.e. 200 cm/h, 100 cm/h, 50 cm/h). Effluent samples under the velocity of 200 cm/h during the 3rd stage (i.e. tap water injection) were not collected. The EC and pH values of tap water were 51.4 μS/cm and 7.7 respectively. 2) Figure 6. (a) Tracer test in the radial flow cell prior to the MICP treatment cycles; (b) Changes in EC at the sampling port during the 1st, 3rd, 5th, and 7th cycle of injections of bacteria solution and cementing solution. The EC shifts to the right due to a reduction in the injection rates from the 1st to 7th injection cycles. 3) Figure 7. Changes in (a) EC and (c) pH of the aqueous solution collected from the effluent port in the radial flow cell; zoomed values of (b) EC and (d) pH during the 3rd MICP treatment cycle. 4) Figure 8. Permeability evolution of the soils in the radial flow cells as a function of MICP treatment cycle, which were calculated based on different pressures monitored at the injection well (p0), the sampling port (p1), and outer boundary (p2). 5) Figure 9. (a) Permeability of the post-treated cores (blue solid dots) and three poorly-cemented sand samples near the southern boundary (red solid triangles), plotted against distance to the central injection well. 6) Figure 10. Unconfined compressive strength (UCS) plotted against CaCO3 content for the biocemented soils in this study and from the literature. 7) Figure 11. 2-D spatial distribution UCS of the post-treated medium-graded very gravelly sand in the flow cell. 8) Figure 12. Triaxial tests of the two treated samples (#1, #2) and an untreated sample under consolidation-drainage conditions (effective confining stress of 100 kPa). (a) deviatoric stress and (b) volumetric strain versus axial strain during the shear stage. 9) Figure S1. (b) Particle size distribution based on wet sieving method. 10) Figure S3. Changes in permeability of one of the core samples under different confining stresses. 11) Figure S5.Darcy velocity in the radial flow cell at the injection rate of 2.88 L/min. The model simulated result matches excellently to the analytical result. 12) Figure S6. Changes in electrical conductivity of 18 ml urea added with 2ml bacteria (~1 OD600) for the determination of the specific urease activity for each MICP cycle. 13) Figure S7. Urease activity of the injected bacteria for each treatment cycle. 14) Figure S8. Electrical conductivity and pH of (a) the injected bacteria solution, and (b) 0.5 M cementing solution (urea & CaCl2) for each treatment cycle. 15) Figure S9. Changes in EC (a) and pH (b) of 36 ml 0.5M cementing solution added with 4 ml bacteria (OD600=1) in DI water. 16) Figure S10. (b) the percentage of fines (&lt;63 µm), sands (63 µm - 2 mm) and gravels (2 mm - 10 mm) of the original soils (S0) before MICP treatment and after MICP treatment (averaged from the three samples); (c) particle size distribution of the soil samples S0 (original soil), S1, S2, and S3, measured after the fines (&lt;63 µm) were washed out and sieved through a 63 µm mesh based on wet sieving method; (d) the overall particle size distribution of the four soil samples (S0, S1, S2, and S3) including the washed fines.