Analysis of Strength Characteristics of Q₃ Loess in Continuously Humidified Conditions

Q₃ loess is a kind of loess with strong collapsibility. After soaking and saturation in water， its collapsibility disappears and then converts into a high compressibility soil. Generally， it is in an undercompacted state under natural conditions， exhibiting high compressibility， large deformation， low bearing capacity， poor engineering performance， etc.， which is easy to lead to engineering accidents. The stress-strain relations and strength characteristics of Q₃ loess with continuous humidification under different initial overburden loads were studied by conventional triaxial tests with GDS unsaturated soil triaxial apparatus. The results showed that the stress-strain curves of Q₃ loess were hardened in the process of continuous humidification. The smaller the degree of humidification， the greater the consolidation pressure， and the higher the stress-strain curve； when the initial overburden load was 0 to 100 kPa， the rise of the stress-strain curve was low and flat， and when it was greater than 100 kPa， the rise of the stress-strain curve gradually steepened. Under all test conditions， the failure line of p-q strength was approximately linear； the strength of Q₃ loess was closely related to its water content and initial overburden load. With the increase of water content， both cohesion and internal friction angle exhibited nonlinear attenuation； with the increase of the initial overburden load， they first decreased and then increased.