Water retention curves and tensile strength for studying desiccation cracking of compacted clay soils

University of Liege, Faculty of Applied Sciences, ArGEnCo Department, 4000 Liège, Belgium

^* Corresponding author: h.ebrahimisadr@uliege.be

Abstract

Desiccation cracking is a natural phenomenon caused by drying in near-surface earth soils subjected to constrained shrinkage. In this research, the water retention curve of two clayey soils, prepared by compaction under standard proctor conditions, are determined to study the desiccation cracking. Two techniques of suction control are applied to control the drying process and to reach the water retention curve of the soils. For the suction values higher than 4 MPa, the saline-solution method was used to impose variousrelative humidity and so, various suctions. In addition, the osmotic method was applied for the suction values between 0.5 MPa and 2 MPa. Additionally, the dynamic vapor sorption (DVS) technique is used to corroborate the water retention curves obtained with the two other techniques. The volume changes is also tracked showing significant shrinkage upon drying. To reach the tensile strength of the soil, the Braziliantest is performed on samples prepared by compaction and submitted to various suctions. According to the results, for the two tested soils, the soil with the higher plasticity index shows consistently the higher retention capacity and the larger shrinkage upon drying. Also, the obtained water retention curves exhibit a smooth transition when the suction control technique change (at suctions between 2 and 4 MPa).