|
Abstract The effect of pile driving velocity is considered. The movement status of the soil element in the elastoplastic interface is chosen as a reference criterion；and the stresses，displacements of any point in the field are described as the functions of R and r，which are the radius of plastic area and the distance of soil element to the center after the expansion respectively. The small-strain theory is used to obtain the equation that the relative velocity should be satisfied，and is defined as the ratio of the expansion velocity at r to the one on the elastoplastic interface，where the latter is composed of two parts：one is caused by the expansion itself —displacement velocity，another is supplemental velocity and is attributed to the deformation of the soil elements because of the expansion，which leads to the soil elements continuously going into plastic station. Finally，combining with the known condition of expansion velocity，the radius of plastic area and failure area of the soil around the pile after the pile driving can be deduced. The theories can provide instructions for some geotechnical engineering problems in unsaturated soil，such as the dynamic penetration of piles，ramming expanded pile and so on.
|
|
Received: 30 September 2006
|
|
|
|
