STUDY INTO THE SIGNIFICANCE OF INDIVIDUAL ELEMENTS IN A PILED-RAFT FOUNDATION

Abstract

Introduction . The prospects of using piled-raft foundations to support the columns of frame buildings and civil engineering works are examined. Aim . To determine the significance and role of individual elements in a piled-raft foundation and its underlying soil to achieve the maximum load capacity. Materials and methods . In order to achieve the stated aim, a series of theoretical numerical studies into horizontally loaded piled-raft foundations was conducted. Here, three-level numerical studies were used to determine the effect of various factors on the load capacity of piled-raft foundations under horizontal and moment loading. The following factors were considered in this work: coefficient of soil reaction around the column pedestal k u ; coefficient of near-pile soil reaction k p ; transverse dimension of the column pedestal d u ; pedestal height l u ; inclination angle of the pile to the vertical α P . The significance of each factor was assessed in terms of the column pedestal displacement at the soil surface level, which is described by a quadratic polynomial in five variables. Results . The impact on foundation resistance to horizontal loading can be determined by analyzing the absolute values of polynomial coefficients and the extent to which the considered factors affect the horizontal pedestal displacement in piled-raft foundations under horizontal and moment loading at the soil surface level. It is established that the most significant factors contributing to the foundation resistance to horizontal loading include the coefficient of soil reaction around the column pedestal k u and the transverse dimension of the column pedestal d u (increasing the foundation resistance to horizontal loading by 60% and 35%, respectively). The other factors have a significantly lower impact. Conclusions . It is shown that numerical theoretical studies into horizontally loaded piled-raft foundations reveal the significance and role of its individual elements and underlying soil, as well as justifying the values of factors affecting the load capacity of foundations.