Geotechnical Investigations and Assessment of Earthquakes Factors at Hurghada City, Red Sea, Egypt

摘要

There is a lack of the geotechnical investigations, at the study area, which contribute to deep understand the site effect which may be lead to amplification of earthquake ground motion especially in the presence of problematic soils and to estimate the earthquake factors. The present work is a contribution to bind the geotechnical investigations and earthquakes studies together at the study area. The present study focuses on the assessment of geotechnical parameters and earthquakes factors of a large occasion's halls project constructing at Hurghada city, Red Sea, Egypt. The geotechnical parameters are including gradation parameters, shear velocity (Vs), shear parameters (frictional angle and cohesion), young modulus (Es), and allowable bearing capacity. The earthquakes factors including soil coefficient (S), limits of constant value for elastic response spectrum (T_B and T_C), and specified value for begin of the constant displacement spectrum (T_D) as well as assessment of design ground acceleration (a_g). To fulfillment these objectives, six mechanical wash boreholes were conducted. Sixty disturbed samples were collected. Several geotechnical tests like grain size analyses, shear velocity (Vs), tri-axial shear, and standard penetration tests (SPT) were carried out. The results illustrated that the a_g-value of the investigated area was 0.25 g. Depending on Egyptian code for vibration and dynamic load foundations, the investigated project area was classified as high potential seismic (zone no. 5A). The earthquakes factors including S, T_B, T_C, and T_D were 1.80,0.10,0.30, and 1.20 respectively. Based on Egyptian code for shallow foundation, the allowable bearing capacity of the investigated soils was ranging from 1.5 to 2.5 kg/cm~2. Structural mat shallow foundations with increasing the weight and the thickness of the reinforced concrete or deep pile foundations were recommended.