Swelling soils are increasingly recognized as a critical issue in geotechnical engineering, as their presence can lead to substantial damage to built structures. When structures are built on such soils and free swelling is prevented, stresses can develop that may lead to significant damage to the structure. Soil stabilization through the use of additive materials has garnered considerable attention as an effective method for mitigating this problem. The objective of this study was to stabilize the clay soil (CH) with high swelling potential by using sea shell, lime and zeolite additives in two stages. In the initial phase, consistency limits were tested by mixing high plasticity clay soil mixed with 8-10-12-14-16% sea shell 0-3-5-6-8% lime (one of the most used soil stabilizer) and 0-5-10-15-20% zeolite by weight. The three mixtures and the two best percentages determined for each mixture were then combined. Upon completing these steps, five experimental sets were prepared by combining the percentages that yielded the best results. Compaction test, percent swelling test and swelling pressure tests were performed with these datas. According to the test results, adding 14% sea shell, 6% lime and 5% zeolite by weight (SS14L6Z5) gave the smallest swelling value as 1,07% and highes swelling pressure as 23 kPa. This study concludes that the combined use of these additives led to a substantial 96% increase in swelling pressure, along with a marked reduction in swelling potential.

The risk of geohazards associated with frozen subgrades is well recognized, but a comprehensive framework to evaluate frost susceptibility from microstructural characteristics to macroscopic thermo-hydro-mechanical (THM) behaviors has not been established. This study aims to propose a simple framework for quantitatively assessing frost susceptibility and compressibility in frozen soils. A systematic THM model was devised to predict heat transfer, soil freezing characteristics, and stress states in frozen soils. Constant freezing experiments and oedometer compression tests were performed on bentonite clays under varying temperatures (-5 degrees C, -10 degrees C, and -20 degrees C) and stress levels to validate the proposed model. Additionally, soil electrical conductivity measurements were employed to assess the temperature- and stress-dependent volumetric and mechanical properties of frozen soils. The model used Fourier's law to compute the transient soil temperature profile and estimated the volume change and stress states based on the soil freezing characteristic curve. Experimental results showed that frost heave of bentonite reached between 9.0% and 26.6% of axial strain, which was largely predicted by the proposed model. It also demonstrated that the frost heave was mainly attributed to the fusion of the porewater. Additionally, the preconsolidation pressure of frozen soils exhibited a rapid increasing trend with decreasing temperature, which was explained by the temperature-dependent ice morphology in the soil interpore. Furthermore, the findings also demonstrated a remarkable sensitivity in the electrical conductivity in response to the soil temperature during the frost heave process and the stress state under the loading or unloading path.