Cairo University

MTPR Journal

 

Re-evaluation of Liquefaction Potentiality for selected pre-liquefied sites associated with 1992 Cairo Earthquake

2016-12-17
Abdel Hafiez H E1, 3, 4, Milad Girgis1, Mostafa Toni 2, 4, Mohamed Taha1
1 National Research Institute of Astronomy and Geophysics (NRIAG),
11421 Helwan, Cairo, Egypt, (Affiliation ID: 60030681)
2 Geology Department, Faculty of Science, Helwan University, Cairo,
Egypt
3 Energy and Bio process Engineering Department, Zewail city for
science and technology
4 North African Group for Earthquakes and Tsunami studies (NAGET)

Vol./Issue: 16 , id: 251

A moderate earthquake (Ms=5.8) was occurred On October 12, 1992 at about 25 km south west of the center of Cairo city and caused a big damage to numerous poorly constructed buildings. Many seismological phenomena were noticed and studied after this earthquake; one of the important phenomenon happened is the soil liquefaction which was associated usually with the occurrence of big sand-boils that was observed in many areas near the epicenter of the earthquake. Recently different methods are used to re-evaluate the liquefaction potentiality, five different sites that showed high liquefaction potentiality during Cairo Earthquake, have been selected to re-evaluate for liquefaction potentiality depending on one the new tools. Shear wave velocity determination provide a promising approach to calculate the factor of safety (FS) against liquefaction, and resistance evaluation of sandy soils against this phenomenon. Multi-channel analysis of surface wave (MASW) method as a recent powerful tool is used to detect the velocity model beneath the studied sites to be used as input for calculation of factor of safety (FS) as an indication for liquefaction potentiality. The aim of this research is to study the potentiality of occurring of the liquefaction phenomenon in a pre-reported sites surrounding Cairo earthquake based on detailed investigation of the soil characterization. The selected five sites named Aquaz, Atf, Bedsa, El-Gammal, Zaweit Dahshour showed a high liquefaction performance during Cairo earthquake which forced us to re-evaluate and update our knowledge through the recent technique about the liquefaction potentiality at these sites. The Factor of safety obtained using shear wave was compared with the values obtained using SPT from previous study of one of the authors, the results show more improvement with reliability through this study beside the accurate calculation of the shear wave, which gave an indication that using Shear wave velocity is a promising tool for re-evaluation of the liquefaction potentiality.