Effect of Embedment on Dynamic Elastic Properties of Pond Ash

Earthquake Engineering

Abstract

The concept of utilizing ash pond areas for the purpose of construction of civil engineering structures on it in earthquake-prone areas or for erection of structures subjected to dynamic loading is a challenging task. Keeping this in view, the studies on dynamic behavior of embedded structures or foundations in pond ash were taken up. The effect of embedment was experimentally investigated by conducting block resonance tests on the samples of pond ash obtained from a particular thermal power plant of India both in the laboratory as well as field. The trend of changes in resonant frequency and maximum amplitude of vibration were obtained for different cases by experimental methods and the recorded values were used for evaluation of dynamic elastic constants and damping ratio. In the field, the block resonance tests were performed as per Indian Standard Code of practice but with a block of reduced size, although same aspect ratio was maintained for ease of handling. The embedment ratios adopted in the tests were also varied under identical conditions of density and deposition parameters. In the laboratory investigation of the pond ash, the tests were performed for the same block resting on the surface as well as in embedded conditions at different embedment ratios in a masonry test tank by closely simulating the field conditions.