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1

Effect of ureolytic bacteria on compressibility of the soils with variable gradation

Wasil Mariola, Wydro Urszula, Wołejko Elżbieta

Architecture Civil Engineering Environment

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2023

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Vol. 16, no. 3

131--139

EN

The aim of this study is to present the effect of treatment with ureolytic bacteria (Sporosarcina pasteurii) on the compressibility parameters of mineral and anthropogenic soils. In the presence of the urease enzyme, secreted by a strain of Sporosarcina pasteurii bacteria, urea hydrolysis occurs, allowing CaCO3 to be precipitated. The literature suggests applying the Microbially Induced Calcite Precipitation (MICP) method to non-cohesive soils. In order to determine whether the biomineralization process occurs in other soil types, cohesive and anthropogenic soils were tested in the laboratory. Compressibility tests were carried out in the laboratory on MICP-treated and untreated soils as reference samples. The process of biocementation in the soil is made possible by the introduction of bacteria into the soil and subsequent activation by a cementation solution (consisting of urea and calcium ions Ca2+). This paper presents the methodology for introducing bacteria into the soil, as well as the effect of the biomineralization process on the deformation parameters of the tested materials.

2

Development of a satellite data based model for homogeneous polygons delimitation, for operational use for the agricultural sector in Poland

Gatkowska M., Wróbel K., Paradowski K., Wyczałek M.

Geoinformation Issues

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2017

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Vol. 9, no. 1(9)

53--61

EN

The paper presents a model for homogeneous land-soil units delimitation on the basis of three main components: NDSI index (Normalized Difference Soil Index) calculated on the basis of Sentinel-2 satellite data for bare soil, NDVI (Normalized Difference Vegetation Index) calculated also on the basis of Sentinel-2 satellite data for vegetation in the end of growing phase and the DTM (Digital Terrain Model) derived from the SRTM mission. The stages of development of the designed model are presented together with the assumptions and thesis applied. The applicability of the method used and further steps to be performed are explained. The comparison of the results of land-soil units delimitation derived on the basis of the proposed model with the results of in-field electromagnetic scanning measurements (EM-38) is demonstrated. The model is proved to be applicable for the demarcation of soil managements zones in the fields and the need for its further validation is stated.

PL

W artykule zademonstrowany jest model wyznaczania obszarów jednorodnych, pod kątem właściwości gleby, w obrębie pola z jednorodną uprawą. Zaproponowany model jest opracowany na podstawie trzech komponentów wejściowych: wskaźnika NDSI obliczonego na podstawie obrazu satelitarnego gołej gleby zarejestrowanego przez satelitę Sentinel-2, wskaźnika NDVI obliczonego na podstawie obrazu satelitarnego Sentinel-2 dla uprawy pod koniec okresu wegetacji oraz Numerycznego Modelu Terenu DTM, pozyskanego z misji SRTM. W artykule przedstawiono krótki przegląd literatury dotyczący zastosowania teledetekcji satelitarnej dla szacowania parametrów gleby. Ponadto w artykule zaprezentowano etapy opracowania modelu, przyjęte tezy i założenia, jak również dalsze kroki rozwoju modelu i jego zastosowania w operacyjnym serwisie ASAP.

3

Influence of loading history and boundary conditions on parameters of soil constitutive models

Kowalska M.

Studia Geotechnica et Mechanica

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2012

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Vol. 34, nr 1

15-33

EN

Parameters of soil constitutive models are not constant. This mainly concerns the strain parameters. What influences their values is not only soil type, structure and consistency, but also the history of stress and strain states. So, it is the question of the current state but also of what happened to the subsoil in the past (regarding geological and anthropological activity) and what impact would have the planned soil-structure interaction. This paper presents an overview of the literature showing how much the soil constitutive model parameters depend on loading and boundary conditions of a particular geotechnical problem. Model calibration methods are shortly described with special attention paid to the author's "Loading Path Method", which allows estimation of optimum parameter values of any soil constitutive model. An example of the use of this method to estimate strain parameters E and ? of Coulomb-Mohr elastic perfectly plastic model is given.