The paper presents results of numerical calculations of a diaphragm wall model executed in Poznań clay formation.Two selected FEM codes were applied, Plaxis and Abaqus. Geological description of Poznań clay formation in Poland as well as geotechnical conditions on construction site in Warsaw city area were presented. The constitutive models of clay implemented both in Plaxis and Abaqus were discussed. The parameters of the Poznań clay constitutive models were assumed based on authors' experimental tests. The results of numerical analysis were compared taking into account the measured values of horizontal displacements.

During firing from a mortar, an important issue is the parameters of compressibility of the ground on which the mortar is placed. This affects the operation of the mortar (including safety). During the qualification tests of the mortar, the influence of different types of terrains on its strength and work during shooting should be examined. Until now, in the Polish standardization documents there was no clear description of the ground parameters used for these kinds of tests. Analysis of the literature also did not allow to determine the dependence of the mortars displacement in the function of the type of ground and its geotechnical parameters. In view of the above, it has become important to draw up a research problem in the form of determining the types of soil with parameters, enabling the mortar tests to be carried out in conditions as close as possible to combat conditions. Therefore, the authors carried out the theoretical calculations and field tests with the use of geotechnical methods such as static and dynamic load tests to determine the parameters of the ground for mortar testing. Preliminary tests were conducted using the prescribed measurement methods and a comparative mortar firing test. Subsequently, an analysis of the results was carried out and the possibilities of using the tested methods of measuring the parameters of soil compressibility were determined.

During firing from a mortar, an important issue is the parameters of compressibility of the ground on which the mortar is placed. This affects the operation of the mortar (including safety). During the qualification tests of the mortar, the influence of different types of substrate on its strength and work during shooting should be examined. Until now in the Polish standardization documents was no clear description about the substrate parameters used for this kind of tests. Analysis of the literature also did not allow to determine the dependence of the mortars displacement in the function of the type of substrate and its geotechnical parameters. Therefore, the authors carried out analytical and experimental analysis of the use of geotechnical methods to determine the parameters of the substrate for mortar testing. The paper presents the proposed types of standardized soil and their research methods. Preliminary tests were also carried out using the prescribed measurement methods and a comparative mortar firing test. Subsequently, an analysis of the results was carried out and the possibilities of using the proposed methods of measuring the parameters of soil compressibility were determined.

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