EXPERIMENTAL INVESTIGATION OF STRESSES IN SAND DURING THE INSTALLATION AND LOADING OF THE SHORT DISPLACEMENT PILE

Nowadays it is possible to find many experimental and analytical studies aimed for better prediction of sand soil response during the installation and loading stages of displacement pile. The interaction between the soil and the pile is very complex, this is the reason why it is not exhaustively described, so far. Response of the soil, especially the ultimate state necessitates investigate the nature of soil response via tip and shaft as well as their relation. Qualitative evaluation of the stress state influence on pile behaviour serves for more clear description of the soil ultimate response mechanism. Current investigation presents the results of two specific instrumented piles tests. The 1st type of the tests revealed the shear and normal stresses distribution at particular areas of short displacement pile interface during static vertical load test. The 2nd type of the tests showed the radial stresses increment paths in the soil during the pile installation stage. The performed tests of the short displacement piles results cleared, that during the static load tests the highest shear stresses, on the pile skin, get concentrate near the pile tip and during the installation stage the radial stresses significant increase when pile tip gets near the push in load cells measurement plane.