## 1 Introduction
\begin{table}
\begin{tabular}{c c c} \hline
**Type** & **Cement–Bentonite Wall [10]** & **Slurry Trenche [11]** \\ \hline Relative advantages of soil-bentonite cut-off walls & Soil–bentonite walls have good plasticity and can handle settlement or deformation. They can also expand to fill minor cracks when wet. & Soil-bentonite walls are more impermeable than slurry trenches, with less waste and lower environmental impact during construction. \\ \hline Relative limitations of soil-bentonite cut-off walls & Soil–bentonite walls are low-strength. They deform or be damaged in complex geology or long-term water flow. In acidic or convective settings, they corrode easily, reducing seepage control. & Soil–bentonite wall construction is complex and slow, involving mixing and laying. It also performs poorly in complex geology. \\ \hline \end{tabular}
\end{table} 
Table 1: Relative advantages and limitations of soil-bentonite walls. Figure 1: Schematic diagram of the process of seepage control and blockage of vertical separation walls [8]. studies published through 2025. These articles were systematically retrieved from two authoritative databases: the Web of Science (WOS) and the China National Knowledge Infrastructure (CNKI). Through a rigorous manual screening process, each publication underwent critical evaluation based on its thematic relevance and scientific contribution to the field of soil-bentonite vertical cut-off wall performance in heavy metal-contaminated environments. This methodological approach ensured comprehensive coverage of current research advancements while maintaining rigorous selection criteria. The systematic analysis not only elucidates emerging trends in this domain but also provides critical insights into the functional interplay between soil-bentonite vertical cut-off wall systems and heavy metal contamination mitigation strategies. Table 2 clearly presents the breakthroughs of this study in environmental complexity, material diversity, technological innovation and practical applicability through multi-dimensional comparisons, highlighting its academic value and engineering significance in the field of contaminated site management. Of the articles listed, 63 are from the period 2020 to 2025 and reflect the latest research on the performance of soil-bentonite vertical cut-off walls in heavy metal-contaminated environments. This ensures that the findings are based on the most recent methodological, technological, and theoretical frameworks. This timeframe captures the latest trends, including new materials, methods, and evaluation systems, thereby increasing the relevance and applicability of the research. Additionally, by analyzing recent literature, this study identifies new challenges and opportunities that arise in the assessment of soil-bentonite vertical cut-off walls. This ensures that the conclusions drawn in the research are consistent with the current state of knowledge and practice in the field. This approach not only strengthens the validity of the research but also positions it to make a meaningful contribution to ongoing discussions and future advancements in the discipline. This study investigates the long-term service performance of soil-bentonite (SB) vertical cut-off walls, systematically summarizing key influencing factors and potential improvement strategies while presenting recent advancements in research on their impermeability and anti-clogging characteristics under diverse environmental conditions, including chemical exposure, freeze-thaw cycles, and wet-dry cycles. The paper critically examines current service evaluation theories for vertical containment cut-off walls and compiles existing in situ evaluation methodologies, aiming to establish a comprehensive reference framework for assessing SB vertical cut-off wall performance. Section 2 provides an analytical discussion on the service behavior of soil-bentonite vertical barriers and corresponding enhancement measures. Section 3 presents a detailed analysis of chemical compatibility