Shear Strength–Based Determination of the Effective Stress Parameter in Unsaturated Compacted Clayey Soils: Experimental Investigation and Microstructural Interpretation - 2026
Shear Strength–Based Determination of the Effective Stress Parameter in Unsaturated Compacted Clayey Soils: Experimental Investigation and Microstructural Interpretation
[en] The χ parameter in the generalized effective stress formulation for unsaturated soils aims at weighting the contribution of suction
on the magnitude of effective stress. It is usually expressed as a function of the degree of saturation. This paper presents a comprehensive
methodology to calibrate this χ parameter, based on ensuring a unique shear failure criterion when the stresses are represented in terms of
generalized effective stress. The method requires knowing the intrinsic strength parameters (effective cohesion and friction angle) from triaxial
compression tests upon saturated conditions, and the uniaxial compression strength at various suction levels. The effectiveness of the
proposed methodology is verified by applying it to three different compacted clayey soils. Then, the microstructural significance of the obtained
relationship between the χ parameter and the degree of saturation is discussed from pore size distribution analyzed from a bimodal perspective.
The macroscopic effective stress is primarily governed by the water residing in macropores (interaggregate region), while the water
retained within micropores (intra-aggregate region) has a negligible effect on the χ parameter.
Disciplines :
Civil engineering
Author, co-author :
Ebrahimisadr, Hesam ; Université de Liège - ULiège > Urban and Environmental Engineering
Lanckohr, Sophie ; Université de Liège - ULiège > Urban and Environmental Engineering
François, Bertrand ; Université de Liège - ULiège > Urban and Environmental Engineering
Language :
English
Title :
Shear Strength–Based Determination of the Effective Stress Parameter in Unsaturated Compacted Clayey Soils: Experimental Investigation and Microstructural Interpretation
Original title :
[en] hear Strength–Based Determination of the Effective Stress Parameter in Unsaturated Compacted Clayey Soils: Experimental Investigation and Microstructural Interpretation
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