Energy transfer measuring in dynamic probing test in layered geological strata

Abstract

Static and dynamic probes are commonly used performing engineering geological investigations in Lithuania. Due to their peculiarities, static cone penetration tests (CPTu) are most suitable for penetration of relatively weak soils. In case of deeper soil layers covered with strong soils was investigated Dynamic penetration test (DPT) is the only that could be used. In Lithuania, the most common bearing strata of foundation are glacigenic and alluvial deposits of Pleistocene age. Geotechnical properties of separate strata may differ significantly. Despite the fact, that the dynamic probing is a relatively cheap comparing with CPT investigation method, it has some significant disadvantages. The main disadvantage of reliability of DPT test results is related with transfer of driving energy through the drive rods to the cone tip. Three tests with attached sensors to the rod were performed in layered geological strata to obtain energy transfer parameters. CPT test was done after DPT for obtaining soil stratification and geotechnical soil properties promiscuity at a distance of 1.5 m. The field tests were performed at a site that is located in northeast part of Vilnius, near the complex of buildings of Vilnius Gediminas Technical University in Saulėtekis district. From geological point of view this part of Vilnius is stratified of glacigenic deposits.