Hello Ariadne

Thanks very much for your high quality response as usual. I will read them and come back.

Best regards

Ravi

Good Morning Ariadne

From the research papers you have sent, I found that cohesion and friction angle are obtained from published literature. But, in my opinion, these parameters should be verified with soils tests as well.

Thank you for your help

Best regards

Ravi

Good Evening.

Soil strenght depend in initial state and water contet. Please see the link.

Regards

Article Some investigations about the tensile strength and the desic...

Good Morning Houcem

Thanks for the comment and the research paper. I totally agree with you. Shear strength will reduce with increasing water content. It means that geotechnical engineers should be aiming at equilibrium moisture content and the relevant shear strength in designing retaining wall.

Best regards

Ravi

check this