Design of Foundation Footings on Fly Ash Under Axial Loading

Abstract

Nearly 65,000 acres (27) of valuable land is occupied by ash ponds. The pond ash deposits are characterized by its very low bearing capacity and high compressibility, rendering them unsuitable for any civil engineering structures constructed over it. Any construction activity over abandoned ash ponds needs a proper understanding of the physical and mechanical properties of these deposits and also the suitability of any ground improvement techniques that can be adopted. Even though adequate substitute full scale field tests are not available. Tests at laboratory scale provide a means to closely control many of the variable encountered in practice. The trends and behaviour pattern observed in the laboratory tests can be used in understanding the performance of the structures in the field and may be used in formulating mathematical relationship to predict the behaviour of field structures. Keeping this in mind laboratory investigations were carried out to determine the physical and mechanical properties of pond ash. In addition, axial load tests were carried out to determine the settlement behaviour of footing specimens. The article outlines experimental work undertaken, the methodology adopted and the salient test results.