Large-scale engineering projects frequently involve pit excavation and wetland landfill operations, resulting in significant silt accumulation that occupies land and adversely affects the environment. Curing technology offers a solution for reusing this waste silt. In this study, straw ash and calcium carbide slag are proposed as effective curing agents for silt soil. Various indoor tests were conducted to evaluate the mechanical properties of the cured silt soil, while X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze its mineral composition and micro-morphology. The results showed that increasing the curing agent dosage significantly improved soil strength. Specifically, at a 10% dosage, the California bearing ratio (CBR) value increased to 18.7%, which is 13.4 times higher than untreated silt soil and exceeds road specifications by 8%. At a 20% dosage, the unconfined compressive strength (UCS) value reached 1.38 MPa, meeting the >= 0.8 MPa requirement for roadbeds. Based on economic considerations, a 20% dosage of straw ash-calcium carbide slag was selected as optimal. Microscopic analysis revealed that the addition of these agents promoted the formation of hydrated calcium silicate, filling pores and enhancing the mechanical properties of the cured soil, resulting in a more dense and stable structure.

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.

This study uses a hollow cylindrical apparatus to explore the effects of principal stress rotation on saturated silty soil, focusing on the static characteristics affected by cycle counts, intermediate principal stress coefficient ( b ), and rotational angle (alpha). As the principal stress axis rotates, strain fluctuations decrease and stabilize, with consistent strain trends observed across various b values. Anisotropy appears around 60 degrees during the first cycle, significantly impacting radial strain while torsional shear strain remains less affected. Distinct hysteresis loops in shear stress-strain relationships reveal initial unclosed forms due to plastic strain accumulation, transitioning to closed loops with increased cycling, and showing noticeable variations in shear stiffness. As b values rise, stiffness degrades, influenced by both b values and a angles. Volumetric strain shows a linear increase for two cycles before decelerating, with b =1 demonstrating anisotropy at 60 degrees and other values at 90 degrees. Minimal contraction occurs for b =0 after the tenth cycle, while b =0.5 sees significant volume reduction. Higher b values also reduce non-coaxial behavior, linked to the initial principal stress orientation. These findings enhance the understanding of silty soil behavior under stress rotation, offering valuable insights for geotechnical engineering applications.