Effects of cyclic freezing and thawing on the shear behaviors of an expansive soil under a wide range of stress levels

The focus of this paper was directed towards investigating the influence multiple freeze–thaw (FT) cycles on mechanical behaviors an expansive soil under a wide range confining stresses (σc) from 0 to 300 kPa. Consolidated undrained (CU) shear tests with pore pressure measurement (σc = 10–300 kPa) and unconfined compression (UC) were conducted FT impact specimens derive shearing stress–strain relationships associated properties including (i) failure strength (qu), elastic modulus (Eu), effective apparent cohesion (c′ c), friction angle (ϕ′ ϕ) obtained CU (ii) qu reloading (E1%) stress (Su1%) at 1% strain UC tests. Besides, structure investigated using mercury intrusion porosimetry (MIP) scanning electron microscope (SEM) Testing results show that mainly soil’s macropores diameters between 5 250 μ. Cracks develop during result in slight swelling which contributes increase global volume specimens. There is significant reduction after cycles. They typically achieve equilibrium about six curves transit strain-softening strain-hardening as increases. A simple empirical model developed well describe behavior low stresses.