On stability of three-dimensional isolated piles in anisotropic swelling soils

Depending on the kind of end effects there may appear in a pile three-dimensional stressed deformed state, not plane one. In this case one should take into account pile torsion. Thus, it is evident that to solve pile stability problems a geometrically non-linear thory of three-dimentional bars must be used. In considering contact of the pile under study with soil an allowance for anisotrogy of the soil is required. If in the plane case coefficient of rigidity in the horizontal plane is an important indicator of the soil in lateral bending of the pile it is necessary to take into account torsional rigidiry acid also that in the vertical direction when studying the three-dimensional state. These two coefficients are essential in studying the swelling soil as an experiment shows that rigid cohesion is peculiar to the kind of soil under investigation. For solving the stated problem of non-linear equilibrium of a three-dimentional bar situated in the anisotropic soil it is expedient to employ of variation principles, the Reisner's prinsiple in particular. On the basis of this principle a system of determining equations is obtained in this research. Initially the variation principle for computing a three-dimensional elastic body in contact with anisotropic elastic medium is presented.