ABSTRACT
Due to the position and the high importance of Baghdad city as the capital of Iraq with its very high population of about 10 million, and its subjection to frequent earthquakes in the last decade. This study tries to assess the factor of safety against liquefaction potential indices (LPI) for the most critical seismic situations under the effect of seismic loading during earthquakes. Huge data were used for 630 boreholes represent 200 site location points for many different types of projects spread all over the city has been chosen and analyzed using special soft wares. Input data of the studied sites represent soil geotechnical properties at different depths such as the total borehole depth, the ground water level, standard penetration number (N), unit weight, and fines content. Six earthquake magnitudes with 0.5 interval (ML=4, 4.5, 5, 5.5, 6, and 6.5) have been chosen to analyze the data. Only 121 points show susceptibility to liquefaction. Three mathematical equations were proposed for analyzing the studied ten factors. Three equations with their accuracy were proposed for points with high percent of clay, points with high percent of silt, and points with high percent of sand. The probability of ground failure (PG) and the calculated LPI was considered for assessing liquefaction risk. As the probability of liquefaction (PL) and the probability of ground failure (PG) are considered to be better measure of liquefaction potential than the factor of safety, so they were determined using the factor of safety and L.P.I.
