INVESTIGATION OF STRAIN STATE OF BASE OF THE FRAGMENT’S MODEL OF THE PILE FOUNDATION DURING STAGED LOADING OF ITS ELEMENTS IN THE SOIL TANK

Changes of stress strain state of the fragment's model of the pile foundation's base depending on load sequence change should be investigated. Methodology. There are laboratory three test runs of the fragment's model of the pile foundation carried out at the soil tank, unlike staged of loading and square of weight square on the soil under the plate raft with the including of pile. Results. There are laboratory confirmations of change of strain-stress state of pile foundation base depending on its elements' load sequence change and confirmations of the influence of piles preloading on their settlement reduction. Originality. Carried out series of tests under the spatial invert with step-by-step loading of model elements of pile foundation fragments (the II and III test runs) showed that such sequence of foundation load allows it to take heavier loads under the condition of the same values of settlement. The model of pile foundation's fragment with additional loading of pile (III test run) showed that such sequence of foundation load allows it to take heavier loads in comparison to the I test run. Practical value. Upon condition of staged including of all elements of the pile foundation, prestressed strain state (additional skin frictions), around the model of the pile, at some point, which facilitates the movement of the pile's model, not connected with the plate. There are laboratory confirmations of dependencies that the more the weight square under the plate is, the greater the displacement of pile's fragment. This effect can be useful for preloading piles in the real building, and to help align the piles' settling within the limits of the pile field, before the transfer of operational loads.