Dynamic Response Analysis of Ash Dyke and Evaluation of Different Construction Methods

The large disposal problem of fly ash can be minimized by using it to the maximum possible extent in the various geotechnical fields. When it is used in geotechnical applications such as the construction of ash dykes in earthquake-prone regions, maintaining its stability becomes a major concern because earthquake-induced instability can cause large lateral spreading of the ash material. Due to the inertia of height-raised ash dykes, earthquake generates significant horizontal and vertical forces. This allows the amount of particulate material to decrease its volume, causing a rise in pore pressure, and a decrease in the strength of the soil, leading to partial or complete collapse of the ash dykes. Mitigation of this problem requires a profound understanding of its dynamic behavior. In addition to this, different methods of raising ash dyke largely affect the performance of dyke during a seismic event. A dynamic response study and an analysis of the developing instability, which can be described in terms of amplification or displacement, are necessary for evaluating the performance of ash dykes under seismic loading circumstances. In this study, the suitability of the methods of raising ash dyke is proposed under the dynamic conditions. Efforts are made to perform dynamic response analysis of ash dyke by determining the amount of displacement and amplification in the ash dyke when it is subjected to earthquake motions. From dynamic response analysis of the ash dyke, it is obtained that the earthquake-induced displacement of the dykes can be as high as 4–5 m, and in the staged construction of ash dyke, upstream method of construction may not be a good alternative to be used in the earthquake-prone regions.