Quantifying Biomediated Ground Improvement by Ureolysis: Large-Scale Biogrout Experiment

TLDR

Biogrouting is a biological ground improvement method that uses microorganisms to induce carbonate precipitation in the subsurface, thereby increasing the strength and stiffness of granular soils. The study investigates the feasibility of biogrouting for ground improvement in a large‑scale (100 m³) experiment using field‑scale techniques and equipment. The authors conducted a 100 m³ field experiment, applying biogrouting with standard techniques and equipment to assess its performance. In situ geophysical monitoring and post‑treatment strength tests showed a significant stiffness increase after one day, with the magnitude correlated to injected volume and distance from injection points, providing a benchmark for future biomediated ground improvement.

Abstract

Biogrouting is a biological ground improvement method, in which microorganisms are used to induce carbonate precipitation in the subsurface in order to increase the strength and stiffness of granular soils. In this paper the results of a large-scale experiment (100 m3) are presented, in which the feasibility of biogrouting as a ground improvement method is investigated using techniques and equipment similar to those used in potential applications. In situ geophysical measurements were used to monitor the biogrouting process during treatment and indicated that the stiffness had increased significantly after one day of treatment. The results of unconfined compressive strength tests on samples which were excavated after treatment were used to assess the distribution of mechanical properties throughout the cemented sand body, which correlated quite well with the results of the in situ geophysical measurements. The stiffness increase could be quantified as a function of the injected volume of grouting agents and the distance from the injection points. These results will serve as an important benchmark for future applications of biomediated ground improvement.