Seismic Analysis of Bunds Considering Coconut Root Reinforcement

Abstract

This thesis focuses on exploring the seismic stability of Traditional Goan Saraswat Bunds newline(TGSB) and the contribution of coconut roots in strengthening it. TGSB is the only newlineembankment in the world that carries a double row of coconut trees planted along the two newlinesides and have functioned for centuries. The TGSB has survived storms of over 150 kmph and newlineother forces that have wrecked destruction for similar incidents in other parts of India and the newlineworld. Because of scarcity of land and spurt of construction activities it is extremely important newlineto carry out research towards sustainable ancient structures for use in today s world. Hence newlinethese ancient geotechnical embankment structure called variously as and#8215;Traditional Goan newlineSaraswat Bunds or just and#8215;Bunds and locally as and#8215;Baand , that has lasted for millennia deserved newlineto be studied. This present work aims to discover the explanation for this longevity and newlinesustainability using computer-based analysis. newlineIn the literature review, extensive reassessment of available literature on TGSB and soils, soil newlinestabilization, roots and earthquakes was researched. No much research was carried out in past newlineon this topic, hence the data available for similar structures was studied for optimized newlinecomputerized analysis. A critical analysis of the literature searched showed that there was no newlineprevious research carried out in this area. There was consequently sufficient gaps and scope newlinefor this research. The problem of no previous research meant that extensive parallel research newlinehad to be done and reviewed. It was seen that there is scope for finding the seismic slope newlinestability of TGSB by different methods. At the same time, a very-brief analysis of liquefaction newlineand tsunami safety was needed as it is a vital part of seismic stability analysis. newlineIn the methodology, first the TGSB is studied for its geometric and geotechnical properties. newlineThe soils used and the soil stabilization used traditionally in TGSBs was studied to reaffirm newlinethe proportions traditionally used. The reason that the TGSB have lastedOnce the required data was found out the analysis was carried out. Computer based seismic newlineanalysis of TGSB in this thesis has been carried out in limit equilibrium spread sheet and limit newlineequilibrium and FEM software analysis. In the analysis section the thesis initially describes the newlinestatic and dynamic stability using spreadsheets and GEOSTUDIO and MIDAS-GTS-NX newlinesoftware. Two software with different approaches (Limit Equilibrium and FEM) were used as newlinethis is the first study in this area and hence needed self-validation. newlineThe results obtained in the thesis give the fair understanding of the geotechnical reasons for newlinethe long lasting sustainable historic geotechnical infrastructure. From the results we can newlinedetermine the increase in the safety due to the presence of coconut tree roots. We can also see newlinehow the seismic stability increases with the presence of coconut tree roots. newlineThe factor of safety was found out for sliding and overturning at toe using Microsoft excel for newlineexisting 3, 6, 9 m TGSB and additional 12m TGSB. newlineA whole range of methods was used to evaluate the safety of TGSB. The final conclusion can newlinebe thus only be decided by comparing all the methods with each other to get an overall idea of newlinethe factor of safety of TGSB and the trend of the results. newlineThe results arrived at this thesis show that the Factor of safety increases greatly by the action newlineof Coconut tree roots and this explains the sustainability of TGSB. Based on the work newlineconducted in this thesis along with the experimental results, it is possible to draw the newlineconclusion that, Existing TGSBs are statically and seismically safe. newlineTGSB technology can be extended for higher bunds than those in existence with suitable newlinemodification in sizes. From this one can safely deduce that such carbon-negative, sustainable newlinelow-height embankment infrastructures must be replicated in similar situations all over the newlineworld. The present research fills the research-gap by study of the coconut tree root as a natural newlinegeo-reinforcement in embankments. newlineKeywords: Seismic Stability, Traditional Goan Saraswat Bunds, Bunds, Coconut Root Soil