ANALYSIS OF LIQUEFACTION POTENTIAL SOIL USING SPT DATA by Arveen Kaur
Abstract
Liquefaction is the result of undrained failure of saturated, highly contractive (loose sand). When this phenomenon occurs, there are drastic changes to structures which results in loss of life and property. The factors which affect the liquefaction potential are relative density, depth of water table, grain size distribution of soil, confining pressure, peak pulsating stress, amplitude and frequency of shaking, distance from earthquake. The liquefaction hazards are commonly associated with saturated or silty sands having low plasticity and density. In the present study, the SPT data is collected from various resources majorly from Testing & Consultancy cell, Civil engineering department, GNDEC, Ludhiana. Out of the available sites, total 80 Sites borehole data was taken and was selected for further work. Then this selected data was analysed using Liqit Software and same data is calculated on spreadsheets by NCEER Youd et. al methods. Also, the comparison has been made on the basis of factor of safety from Liqit and spreadsheet values. The comparison was represented by graphs for each site. The major work of the thesis was to plot the liquefaction map on GRASS GIS software. The maps were generated depth wise on GRASS GIS software. This gives an edge over one single value of depth. Hence, consecutive depths were chosen to give a broad view of the work done. The detailed analysis of how to generate the Graph is also mentioned and given in Annexures. Basic overview of Liqit software is also given in annexure. This thesis will cover as much region as possible for each district in Punjab. Some sites data was discarded due to their very close proximity with other sites
