The long-term compression behavior of clay is significantly affected by temperature paths. However, most studies on temperature paths focus on short-term changes in volume and pore pressure, with limited research on how temperature paths affect soil secondary consolidation characteristics. To experimentally investigate the time-dependent compression behavior of lateritic clay under different temperature paths, a series of temperaturecontrolled isotropic consolidation tests from 5 to 50 degrees C were conducted with consideration of heating/cooling rate and thermal cycle paths. The results indicate that the accumulation of thermal-induced pore water pressure increases with the rate of temperature variations, but a faster rate leads to smaller volumetric changes. Moreover, thermal cycling does not cause irreversible thermoplastic volumetric strain with a suitable heating/cooling rate, and the cycle paths do not influence this outcome. Furthermore, the creep rate of heated samples increases significantly, and the heating/cooling rate also affects the creep rate: a slower heating rate results in a faster creep rate. Additionally, the creep behavior ceased after the thermal cycle, and it appears that the thermal cycle paths have no effect on the creep rate. Finally, this study summarizes the mechanism of the influence of temperature on the creep behavior of clay, and reasonable explanations are proposed for the thermo-mechanical behavior caused by different temperature paths.

As the economy evolves, there has been an increasing interest in exploring oceanic resources. However, the complex marine environment poses several geological challenges for offshore engineering endeavors. The presence of gassy soil significantly influences the deformation properties and integrity of the soil, significantly impacting offshore engineering construction. Triaxial shear tests and creep tests were conducted on gassy clay with silt content, prepared using the laboratory zeolite method, to analyze its shear deformation characteristics and long-term resilience. We proposed a prediction model for calculating the long-term resilience of silt-containing clay, accounting for confining pressure and gas content, and verified its efficacy through experimentation. Our findings reveal the following: The stress-strain relationship curve of silt-containing gassy clay is a typical strain hardening curve. The greater the confining pressure or the smaller the gas content, the greater the stress under the same strain and the greater the yield stress; when the gas content is the same, the greater the confining pressure, the greater the long-term strength of the soil; and when the confining pressure is the same, the smaller the gas content, the greater the long-term strength of the soil. The research results can provide theoretical reference for actual complex engineering.

For rigorous understanding the shallow landslide mechanisms and deformation characteristics of expansive soil slopes, a comprehensive in-situ monitoring platform is established. Triaxial creep tests and microstructure analysis with scanning electron microscopy are also conducted on expansive soil samples obtained from Binxi station. Field monitoring data indicates that freeze-thaw (F-T) cycle and snowmelt infiltration significantly increase the creep deformation of expansive soil slope during spring melting period. Due to the influence of F-T cycle and snowmelt infiltration, more soil grains are involved in the shear deformation contributing to a large, localized shearing. Additionally, the microstructural analysis shows that F-T cycle influences the relationship between expansive soil grains that gradually change from face-face contact to point-face contact or edge-edge contact form. The shallow landslide mechanisms of expansive soil slope are revealed from creep deformation and microstructure characteristics of soils after the F-T cycle and snowmelt infiltration, which can be summarized into two stages, namely, the snowfall accumulation state and snow melt-shallow infiltration stage. These results can serve as a good reference for the prevention of expansive soil slopes in seasonally frozen regions.

Cement reinforcement can effectively mitigate the frost heave and thaw settlement in soft clay during artificial ground freezing. Generally, soft clay has strong creep characteristics, which is also the main factor influencing the construction safety in coastal area. However, the mechanism of freeze-thaw action with cement reinforcement on the creep is really unclear. In this paper, the creep characteristics of cemented-soil after freeze-thaw have been investigated through triaxial creep test, and the micro-mechanism has been explored by Scanning Electron Microscopy (SEM) test and PFC numerical simulation. Three quantitative parameters of porosity, average particle size, and particle roundness have been extracted from SEM pictures. The results showed that creep deformation of cemented-soil is higher after freeze-thaw than before, with an increase as the freezing temperature drops. When combining freezing with cement reinforcement, there is an overall decrease in the creep behavior. It was observed from numerical simulation that the slip deformation of cemented-soil particles is generated from top to bottom and from outside in. Moreover, the porosity of cemented-soil increased from 24.5 to 28.5%, the particle roundness decreased from 2.11 to 1.75, while average particle size decreases from 16.67 to 13.88 mu m during creep process. These shifts are explained by particles sliding and disordering, with debris migrating to the interior of pores. The results provide a scientific reference for the development of underground space in the coastal area.

To ensure the long-term safety and stability of bridge pile foundations in permafrost regions, it is necessary to investigate the rheological effects on the pile tip and pile side bearing capacities. The creep characteristics of the pile-frozen soil interface are critical for determining the long-term stability of permafrost pile foundations. This study utilized a self-developed large stress-controlled shear apparatus to investigate the shear creep characteristics of the frozen silt-concrete interface, and examined the influence of freezing temperatures (-1, -2, and -5 degrees C), contact surface roughness (0, 0.60, 0.75, and 1.15 mm), normal stress (50, 100, and 150 kPa), and shear stress on the creep characteristics of the contact surface. By incorporating the contact surface's creep behavior and development trends, we established a creep constitutive model for the frozen silt-concrete interface based on the Nishihara model, introducing nonlinear elements and a damage factor. The results revealed significant creep effects on the frozen silt-concrete interface under constant load, with creep displacement at approximately 2-15 times the instantaneous displacement and a failure creep displacement ranging from 6 to 8 mm. Under different experimental conditions, the creep characteristics of the frozen silt-concrete interface varied. A larger roughness, lower freezing temperatures, and higher normal stresses resulted in a longer sample attenuation creep time, a lower steady-state creep rate, higher long-term creep strength, and stronger creep stability. Building upon the Nishihara model, we considered the influence of shear stress and time on the viscoelastic viscosity coefficient and introduced a damage factor to the viscoplasticity. The improved model effectively described the entire creep process of the frozen silt-concrete interface. The results provide theoretical support for the interaction between pile and soil in permafrost regions.

We took the silt soil in the Yellow River flood area of Zhengzhou City as the research object and carried out triaxial shear and triaxial creep tests on silt soil with different moisture contents (8%, 10%, 12%, 14%) to analyze the effect of moisture content on silt soil. In addition, the influence of moisture contents on soil creep characteristics and long-term strength was analyzed. Based on the fractional derivative theory, we established a fractional derivative model that can effectively describe the creep characteristics of silt soil in all stages, and used the Levenberg-Marquardt algorithm to inversely identify the relevant parameters of the fractional derivative creep model. The results show that the shear strengths of silt soil samples with moisture contents of 8%, 10%, 12% and 14% are 294 kPa, 236 kPa, 179 kPa and 161 kPa, respectively. The shear strength of silt soil decreases with increasing moisture content. When the moisture content increases, the cohesion of the silt soil decreases. Under the same deviatoric stress, the higher the moisture content of the silt soil, the greater the deformation will be. The long-term strength of silt soil decreases exponentially with the increase of moisture content. If the moisture content is 12%, the long-term strength loss rate of silt soil is the smallest, with a value of 32.96%. The calculated values of our creep model based on fractional derivatives have a high goodness of fit with the experimental results. This indicates that our model can better simulate the creep characteristics of silt soil. This study can provide a theoretical basis for engineering construction and geological disaster prevention in silt soil areas in the Yellow River flood area.

The long-term dynamic characteristics of frozen soil are important theoretical basis for the dynamic stability evaluation of geoengineering in cold regions. Compared to unfrozen soil, the dynamic creep behaviour is more complicated owing to its rheological property. In this study, triaxial tests under cyclic loads with different constant stress amplitudes and confining pressures for frozen silty clay (FSC) are carried out. The long-term dynamic creep process and deformation mechanism under different dynamic stress amplitudes were investigated. The test results show that with the cyclic numbers increasing, the dynamic elastic modulus and the hysteretic loop area decrease because of the damage accumulation in the samples. Also the dynamic strength decreases with an increase in failure cyclic numbers under different confining pressures. Based on the fractional calculus theory, replacing the Newton's dashpot in the traditional Maxwell model with fractional Abel's dashpot, a fractional dynamic creep model is established. Considering the melting and crushing of the ice inclusion, the slip effect in frozen soil is increasingly significant, the viscosity coefficient of dashpot element is decreasing with an increase in loading time. In the proposed model, a non-constant dashpot element is introduced to clarify the constitutive relation of the FSC in the accelerated creep stage. The comparison results confirm that the proposed constitutive model is valid and suitable for reflecting the long-term dynamic creep behaviours of the FSC.