Granular Pile Anchor Foundation (GPAF) System for Improving the Engineering Behavior of Expansive Clay Beds

摘要

Several innovative foundation techniques have been suggested for reducing the detrimental heave of foundations in expansive clays. This paper presents another innovative technique in the form of a granular pile anchor-foundation (GPAF) system for arresting heave and for improving the overall engineering behavior of expansive clay beds. In the GPAF system, the foundation is anchored at the bottom of the granular pile to an anchor plate through an anchor rod. As a result, heave of the foundation is reduced. The laboratory model tests using this new concept of the GPAF system revealed that the heave of the expansive clay beds was reduced by about 96%. The development of final heave was faster in the case of the expansive clay beds reinforced with the GPAF system. The undrained strength of the clay surrounding the granular pile anchor improved by about 20%. The tests on two-group granular pile anchors indicated that heave was reduced to a minimum value when the spacing between the granular pile anchors was kept at twice the pile diameter. The compressive load response of the expansive clay bed reinforced with granular pile anchors also improved. The pull-out load of the granular pile anchors increased with increasing diameter and the relative density of the pile.