NUMERICAL ANALYSIS OF MULTILAYER REINFORCED POND ASH SLOPE
by Harleen Kaur
Abstract
Coal ash is a waste product that is generated when coal is burnt in the thermal power plants. This coal ash is of further many types of which one is pond ash which is present as slurry in the ash ponds. According to the latest available data, 251.69 million tons of coal is used for generation of electricity which led to generation of 86.45 million tons of coal ash. Around 80% is fly ash (which is being utilized by civil engineers) and 20% is bottom ash. Now the task is to utilize this 20% to maintain the environment. In the present study, numerical analysis is carried out in which pond ash is been employed as a fill substance in the embankment slope. The bearing capacity is scrutinized by constructing a rigid footing (plain- strain) on the slope. The main rationale of this research is to scrutinize some prominent parameters which effect the behavior of a strip footing laid on a pond ash slope by the endosure of multiple layers of reinforcement (geo-grid and geojute), to have a better understanding about the fortification (reinforcement) system, and to suggest an appropriate geometry of reinforcement placement. The geo-grid reinforcement used is SGi 040 and geo-jute reinforcement used is DW TWILL. The physical properties of both the reinforcements were taken from the existing literature. To understand this ground improvement method, numerical investigation was conducted using a mercantile finite element software PLAXIS 2D version 8.0 to calculate the bearing capacity using geo-grid and geo-jute. The comparisons are made using two non dimensional parameters i.e. settlement ratio and bearing capacity ratio (BCR). The benefit of using these types of software’s is that they can be effortlessly used to examine geometric models which have not been examined in the laboratory yet. The number of multiple layers used are 1, 2, 3, 4 and embedment ratios used for modeling are 0.25, 0.5, 0.75 and 1.0 with De/B as 1, 2.3. The obtained results depicts that the load-bearing capacity is increased with increasing number of reinforced layers and De/B ratio. With increasing z/B ratio, bearing capacity is seen to decrease significantly. The ultimate bearing capacity comes out to be maximum when N=4. The percentage increase in the bearing capacity while using geo-grid as compared to geo-jute is about 18% approximately. The results of geo-grid and geo-jute are quite comparable, so the later can also be used depending on the requirement of load carrying capacity.
