Soaking test of a large-scale modelling pile embedded in expansion soil ground

By a long-term soaking test observation and measurement of a pile embedded in expansion soil ground,the pile-soil interaction and a series of pile working characteristics were obtained such as pile settlements,distribution of axial force and lateral friction along pile shaft,foundation swell-shrink and their time-related characteristics,etc under the simulative rainfall condition.Test shows the displacement of the pile top with a law of three stages that it firstly goes down,then goes up until achieves a stable status gradually.Tensile stress is distributed along the whole pile,and axial force distribution along pile body presents waviness form on stress numerical axis.There is axial force peak at the middle-lower part of the pile,and the axial force peak increases with time.Neutrality point of the axial force moves upwards from pile end in a certain degree with the passage of time.The load sharing ratio between lateral friction resistance and tip resistance shows a law of three stages that it firstly decrease,secondly increase,then tends to a constant gradually.Experimental study gives a valuable reference to pile design and engineering application.