Interaction between a subsoil and group of piles joined with a raft

Most pile-slab foundations are designed without taking into account the contribution of growth. Although it is well known that the grille plays an important role in overall load-bearing capacity. In such structures, the overall subsidence of the foundation is likely to be small due to the installation of more piles than necessary. However, from an economic point of view, it is desirable that the foundation be designed in such a way that the subsidence is limited to an acceptable level, but taking into account the bearing capacity of growth. The main problem is a work of pile’s group taking into account interaction between piles through a soil base is considered. During the interaction there are additional stresses in the inter-pile space, there is an effect of "compression" of the piles by the soil from the loads transmitted to neighboring piles.  This paper presents the results of a study of the joint work of piles and grilles under the action of static load using numerical simulations. The study used a group of piles (5 pcs.) With a diameter of 420 mm and a length of 10 m, combined with a grid. Fine sand of medium density was used as the basis of the pile foundation. Numerical modeling was performed using an ideal elastic-plastic model with the Coulomb-Mohr strength criterion. The work of piles at different distances between piles (1.5-2.5 m) and grating thickness 300 was compared; 500mm. The interaction of piles and growth-verification with the surrounding soil mass is analyzed. At the lower end of the pile, in the area of contact of the pile with the ground there is a complex stress-strain state. The pitch, diameter, length of the piles, as well as the rigidity of the grille have a significant effect on this stress-strain state. Taking into account the influence of these factors is necessary to determine the patterns of distribution of external loads between the piles and the grille. Irregular settling of the group was revealed piles joined by a grid. The central and extreme piles are included in the work in different ways. It is established that the inclusion of the pile grid in the work depends on its stiffness, as well as the axial distance between the piles. It is investigated that when the distance between the piles changes, the redistribution of forces in the growth piles and piles changes.