The large number of fissures developed in loess affect the creep mechanical properties of the soil body, easily triggering geologic disasters such as loess landslides. To gain a comprehensive understanding of the creep characteristics of fissured loess, we used the undisturbed loess from the landslide group in the Heifangtai area of Gansu Province, China, to conduct triaxial creep tests under various prefabricated fissure angles (without fissure, 30 degrees, 45 degrees, 60 degrees, and 90 degrees) and different matric suction conditions. The stress-strain-time characteristics of fissured loess are analyzed, and the long-term strength variation law of fissured loess is determined. The deterioration effect of loess fissures is revealed, and the creep deformation characteristics of fissured loess samples (FLS) are explored. The results show that: (1) The deviatoric stress, confining pressure, and matric suction significantly affect the creep deformation of fissured loess and the duration for the sample to attain steady-state creep. (2) The fissures have a pronounced deteriorating effect on the long-term strength of loess. As the fissure angle increases, the long-term strength of the loess sample initially decreases and subsequently increases, exhibiting a V shaped variation, while the cohesion demonstrates a comparable V shaped variation. (3) The deterioration coefficient of the fissure initially rises and subsequently declines with increasing confining pressure. (4) The creep deformation characteristics of FLS are categorized into axial deformation, bending deformation, and torsional deformation. Generally, the fissure angle affects the axial strain of the sample; however, an increase in confining pressure weakens the influence degree of the fissure on the deformation. The findings provide new insights into theoretical support for the study of loess mechanics and deformation characteristics in the Loess Plateau region of China. This is significant in elucidating the effect of fissures on the occurrence and development of loess landslide disasters.

In Interior Alaska, a slope underlying the Trans Alaska Pipeline System has recently experienced downslope movement, which is attributed to a buried frozen, ice-rich peat layer. We performed a field investigation of the site, including coring and sampling, and conducted a suite of laboratory tests, including mechanical tests at temperatures between -0.56 and -5 degrees C to quantify the secondary creep behavior and to estimate the impact of soil cooling on the creep deformation. We tested a variety of soils, including ice-rich silt, silty peat, and peat with the majority having an organic content of 10% or greater. The results indicated that temperature has a strong control on the resulting time-dependent mechanical properties. Here we provide secondary creep power law relationships for these soils. The analysis indicates that cooling the soils can be effective in reducing creep movement; for example, cooling by 1.1 degrees C from -0.56 to -1.67 degrees C results in an order of magnitude reduction in the shear deformation rates. These results are significant as they add to the limited amount of work done on the time-dependent mechanical behavior of ice-rich peat and organic soils at warm sub-freezing temperatures.

The residual soil on a slope can slowly move downward under the influence of gravity, forming a creep landslide. These types of landslides are known for their extensive coverage, significant magnitude, and prolonged duration of hazard. A systematic study of the creep properties of creep landslide geotechnical bodies is essential for the analysis of the deformation process and long-term safety evaluation of landslides. This paper focuses on studying a creep landslide involving residual soil in western Henan Province. The creep characteristics of residual soil with different stone content are investigated through direct shear creep experiments. The findings reveal that stone content has a profound impact on the creep behavior of residual soil. As the stone content of the soil increased, the structure of the test soil changed significantly, resulting in a gradual decrease in its shear creep. The Burgers model can effectively fit the deceleration creep and steady-state creep stages of the residual soil. With the increase in stone content, the four parameters of the Burgers model show a significant increase, with the instantaneous elasticity coefficient G1 and the viscosity coefficient eta 1 experiencing more noticeable changes. The average long-term strength of specimens with different stone content is only 54% of their instantaneous strength. Additionally, as the stone content increases, the ratio of long-term strength to instantaneous strength also increases. Notably, the long-term strength of specimens with 10-30% stone content is significantly lower than that of specimens with 50-70% stone content.

Sludge-cured lightweight soils have unique advantages in roadbed treatment due to their properties such as low density and high strength. Its long-term mechanical law based on the superposition of drying-wetting and freezing-thawing (D-W-F-T) is studied through creep experiment. The test results show that: with the increase of the number of D-W-F-T, the deformation of the soil gradually increases, and the deformation tends to be stable when it reaches a certain number of times; the stress-strain isochronous curves are obviously nonlinear in general; The long-term strength increases with the increase of density and confining pressure, and decreases with the increase of the number of D-W-F-T; by comparing the isochronous stress-strain curve cluster method and the steady state creep rate vs. The comparative analysis suggests that the steady state creep rate versus stress level curve method be used to determine the long term strength.