Geotechnical and environmental radioactivity investigations at Al Sadis Min Uktober city, Cairo municipality (Egypt), for the high-speed railway construction.

ABSTRACT

The present study aims to evaluate the possibility of constructing a new high-speed railway (HSR) at Al Sadis Min Uktober city, Cairo (Egypt) geotechnical and environmental radiological hazards are estimated from several collected soil and water samples. A variety of laboratory geotechnical tests such as grain size, free swelling test, liquid and plastic limits, chemical analysis and uniaxial compression strength are applied to sixty-one drill holes. A geotechnical examination of the coarse-grained soil at the foundation level classified it as poorly graded soil. The results of the investigation of fine-grained soil at the foundation level shown that the liquid limit ranges from 22% to 55%, the plastic limit ranges from 12% to 28%, the plasticity index varies from 11% to 33%, free swelling varies from 51% to 71%. Mechanically, the uniaxial compressive strength values on rock samples range from 6.96 MPa to 142.39 MPa. The radioactive study is performed to detect the 226Ra, 232Th, and 40 K activity concentrations of the soil samples their mean values are 34 ± 10 Bq·kg-1, 14 ± 5 Bq·kg-1 and 552 ± 20 Bq·kg-1, respectively. The values of radiological hazard indexes are not exceeded the permissible limits e.g. the mean value of absorbed dose rate is 47 ± 6 nGy h-1; the annual gonadal dose equivalent is 0.3 ± 0.04 mSv·y-1; the lifetime cancer risk is 02 ± 0.2·10-3. Thus, the soil in the studied railway area is safe to use in building materials and infrastructure applications the radiological hazards and the geotechnical studies confirmed the studied area is suitable to construct a new community having a HSR. According to the SWOT-PEST and environmental impact analyses, the construction of the HSR meets the criteria of the Kyoto Protocol, the EU Climate and Energy policy, and other international treaties.