Volume: 2, 2023
2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: E020
DOI: https://doi.org/10.24326/ICDSUPL2.E020
Published online: 19 April 2023
ICDSUPL, 2, E020 (2023)
The mechanical properties analysis of sandy soil treated by biostimulation method
Nadella Marchelina1*, Joanna Fronczyk1, Adam Pyzik1, Małgorzata Franus1
1 Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland
* Corresponding author: d570@pollub.edu.pl
Abstract
Interdisciplinary cooperation in the field of microbiology, geochemistry, and civil engineering led to the development of the more environmentally friendly soil stabilization technology using microbial induced calcium carbonate precipitation (MICP). This method is mainly based on bioaugmentation of significant amounts of exogenous, specifically selected bacterial cultures. However, during the application of bacteria cells into the subsoil several problems arise which are mainly related to inhomogeneity of the CaCO 3 crystals distribution within the soil matrix. One of the suggested approaches to overcome this problem, is stimulation the growth and activity of native bacteria naturally present in the subsoil. Unlike bioaugmentation, biostimulation relies on the improvement of native urea-hydrolyzing bacteria strains by providing an appropriate enrichment and cementation medium. Hence, the current research was performed to evaluate the effectiveness of MICP process carried out as biostimulation in loose sandy soil. Biostimulation experiments were conducted on soil sampled from the Niemce mine, Lublin voivodeship, Poland. The soil was classified as poorly graded fine sand with the grain size in the range of 0 – 0.25 mm. The sand specimens were placed in the boxes with dimension of 16.2 cm x 11.6 cm x 2 cm. Samples were treated with biostimulation solution (a solution designed to increase the population of ureolytic bacteria) and cementation solution (a solution designed to stimulate the precipitation of carbonates) in 6 dosages for each solution. In the final stage of treatment the samples were air dried for 14 days, and afterwards the pocket penetrometer measurements and direct shear test were performed. The results showed that by stimulating the native bacteria in the soil the soil strength parameters may be effectively improved. The pocket penetrometer tests showed an increase of soil strength up to > 440 kPa, while direct shear tests showed the shear strength up to 159.31 kPa and 227.5 kPa for 50 kPa and 150 kPa of normal stress, respectively. Although the precipitation tended to occur in the surface layer of the samples, also at deeper depths of samples larger number of precipitation compared to the bio-augmentation application was observed which indicated more homogenic cementation of sand.
How to cite
N. Marchelina, J. Fronczyk, A. Pyzik, M. Franus, 2023.The mechanical properties analysis of sandy soil treated by biostimulation method. In: 2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL2.E020