Zastosowanie piezoelementów typu bender do oceny sztywności początkowej gruntu nienasyconego z kontrolowanym ciśnieniem ssania

Abstract

The paper presents an evaluation of the influence of the degree of saturation of soil with water on its stiffness in the range of small deformations. Appropriate analysis of the interaction of the building structure with the subsoil carried out with the use of numerical methods requires the knowledge of parameters, in particular stiffness characteristics in the range of deformations corresponding to the actual conditions of the structure’s work. Usually the deformations of the subsoil caused by the structure do not exceed 10–3, therefore it is particularly important for the geotechnical engineer to determine the soil stiffness in the range of deformations 10–5–10–3. In order to determine the stiffness characteristics of cohesive subsoil, a triaxial compression apparatus equipped with piezoelectric elements of bender type was used, enabling the measurement of the transverse wave velocity inside the sample. The base of the described triaxial apparatus is equipped with high-pressure air entry ceramics (HAEV), which allowed to use the technique of “axis translation” to perform tests for variable (controlled) degree of saturation of the soil sample with water. In the literature, the degree of saturation (Sr) and soil moisture are mentioned as one of many factors which, apart from physical properties, values of effective stresses, voids index, stress history and others, infl uence the velocity of wave propagation in the ground. The publication describes the methodology of research and presents the results of own research.