Geotechnical properties calculated from seismic refraction velocity and borehole information for a spillway construction

Abstract

     Seismic refraction and engineering surveys were conducted for three selected sites, Sindbad, Sehan and Albhar sites in Basra sity. The geophysical methods and bore-hole data were gathered to conducted the aim of study.  The results of seismic were compared with direct method information (pore-hole) for further credibility. Thus, 24 seismic refraction profiles were acquired at three different sites in total length of (120) m. The results of P-velocity ranging from (500-517) m/s at first layers of three sites, while ranging between (397-425)m/s at second layer, and was(527-558)m/s  .The results of SH-velocity in the 1^st layer of three sites  ranged from (290-296)m/s at depth  (1-5,6)m , while in 2^nd layer are between(209-237)m/s at depth (5,16)m/s, and in the 3^rd  was  (289-3156)m/s. The bore-hole data were collected from 6 holes allocated 2 holes at each site drilled by Al-Ma'awal Company for soil investigation with depths ranging between (1- 40) m. The study shows close behavior of SPT log and S-wave with depths at the study sites.  According to SPT the consistency soil in three sites divided in to several layers 1st layer   is a very stiff   with bearing capacity (qa) ranged between (11- 41 T/m2) in two study sites at depths (1 to 5, 6.5 m) this layer is suitable for light loads of Shallow foundation. 2nd layer is a soft to medium stiff with (qa) ranged between  (2-9T/m2) at (6, 7 to 18m) depths which unsubtle for foundation because of high water content (28-30%). 3rd layer is a very stiff to hard with (qa) ranged between (12-40 T/m2) at (20 to 40 m) depths because of compaction or a static load this layer is suitable for heavy loads of deep foundation such as spillway structure. The values of bearing capacity (qa) and internal friction angle(Ø) obtained from the seismic method were close to bore hole data. The results of geotechnical parameters obtained by geophysical method and borehole information are   suggest Albhar site is best serve location for a spillway construction.