Improvement CBR of gypseous soil by geogrid under soaking condition

Abstract EN

The presence of gypsum in soils causes significant changes in the behavior and alters the properties of these types of soils.

Gypsum and anhydrite rocks are often found in many countries of the world in extensive deposits.

It was known in Greek as Gypsosa, in German as gips (which could be probably derived from Greek) and in Latin as gypsum.

Large area in middle and west of Iraq is classified as a gypseous soil.

This paper aims to study the benefit of using Netlon CE121 geogrid as reinforcing material on CBR (California Bearing Ratio) which is adopted as an indication for treatment.

A laboratory tests were performed on a gypseous soil samples to study the effect of the first layer location (u) of geogrid and soaking on CBR are studied.

4, 15 and 30 days are adopted as a period of soaking.

CBR corresponding to 14 kN/m3 is adopted as a reference value to make the comparisons.

The results show that the use of geogrid reinforcement increase the value of California Bearing Ratio (CBR) and the location of first layer of geogrid under the surface have a large influence on CBR, the reliable depth is 0.15D where D is the diameter of CBR mold.

CBR value for the optimum point increased almost two times when compared with unreinforced soil.

Also CBR decrease when the period of soaking increases for unreinforced and reinforced soil.

The experimental results shows that the ultimate bearing capacity increase when CBR increase for unreinforced and reinforced soil.