LATERAL LOAD CARRYING CAPACITY OF ROCK SOCKETS

Abstract

Rock sockets are a type of deep foundation that are capable of supporting very large vertical and lateral loads. Rock sockets are widely used as foundations for bridges and other important structures. They are also used to stabilize a landslide. The sockets are constructed by drilling holes from the ground surface to the target depth of rock formation and filling the hole with reinforcing steel and concrete. The main loads applied on the socket are axial compressive or uplift loads as well as lateral loads with accompanying moments. Rock encountered in the foundations are invariably jointed and the load carrying capacity of socket therefore depends not only on the quality of the intact rock but also on the characteristics of rock joints. The most important characteristics of the rock joints which will affect the load carrying capacity of socket are surface characteristics of the joints, frequency of joints and orientation of joints with respect to loading direction. In present study the effect of rock joints on the lateral load carrying capacity of rock sockets has been studied by using equivalent continuum material modelling approach. In this approach the discontinues rock mass is converted into a equivalent continuum which has same properties as those of discontinuum. The most important index properties of the rock mass is the uniaxial compressive strength. A computer program has been developed which initially estimates. the UCS of rock mass by different methods available in literature and based on this UCS value it calculates the shear strength parameters of rock mass. Finally considering the shear strength parameters, the lateral load carrying capacity of rock sockets is estimated using Carter and Kulhawy (1992) method.