The influence of rammed stone column formation process on mechanical parameters of the surrounding weak soil

摘要

The dynamic replacement (DR) is a method of weak soil strengthening widely applied in Poland. However, the design of soil improved in this way pose some problems. The existing methods for dimensioning, due to their assumptions, do not take into account the specificity of dynamic replacement. Therefore, for the last few years, the authors have been investigating different aspects of soil improvement with the use of dynamic replacement method. This paper presents the results of in situ research on the influence of rammed stone column formation process on the surrounding soil. The influence is shown as changes of strength and strain parameters estimated on the basis of the correlation of cone penetration tests (CPTU) results. The tests were performed during and after the stone column formation process, at different time intervals and in points located at different distances from the column. The research shows that DR stone column formation process results in complex changes of mechanical parameters that vary depending on factors such as soil condition, distance from the column and time. The analysis of changes of these parameters (decrease of the initial values occurring at the beginning and their increase after the column formation process) reflects the processes occurring in the closest proximity to the column (degradation, reconstruction and consolidation of the soil).