Effect of chemical composition variations on geotechnical parameters, (Cohesion (c)‎, and internal friction angle (Ø)‎)‎ in Abu-Shaybah and Kikla formations, Gharyan area, Libya

Abstract EN

the variation of chemical composition has a great deal of influence on the geotechnical parameters namely: The cohesive strength and the internal friction angle.

This influence could be due to the variation of cementation materials and their strength.

This study is about the effect of variation in chemical composition on the geotechnical parameters in the study area.

Thirteen cutting samples of Abu-shaybah formation and ten cutting samples of Kikla formation were tested in the lab using the direct shear test, the atomic absorption test, and the flame photometry test.

Based on the laboratory testing, the most common elements in all samples are Aluminum (Al), iron (Fe) and calcium (Ca), the values of cohesive strength and the internal friction angle are ranged from (0 to 0.55) kg/cm2 and from (21° to 37.56°) respectively.

The cohesive strength increases with increasing of carbonate (Mg & Ca) and clay (Al & K) contents in the cementation materials, but the cohesive strength and the internal friction angle are increase by increasing of the element combination ratios (Ca & Mg/Al & K) and (Fe/Al & K).

The multiple regression analysis displays a good agreement between expected and observed values of shear strength parameters.