Research on a Comprehensive Evaluation Model for Soft Foundation Treatment Schemes Based on the Grey–Fuzzy Analytic Hierarchy Process

Due to its weak mechanical properties and poor stability, soft soil often causes uneven subgrade settlement, embankment instability, and collapse. Therefore, the rational selection of subgrade treatment methods is directly related to both engineering quality and cost. Given the diversity of soft soil subgrade treatment methods and the complexity of influencing factors, traditional experience-based judgment makes it difficult to objectively optimize schemes. To address this, this paper constructs a comprehensive evaluation model for soft soil subgrade treatment schemes by combining grey relational analysis and fuzzy Analytic Hierarchy Process (AHP). The model quantifies the correlation between each evaluation index and the target scheme through grey relational analysis, and determines the weights of indicators using fuzzy AHP, thereby achieving an objective selection process. Taking the Airport Avenue–Changji Expressway interchange bridge project as an example, this paper verifies the effectiveness of the proposed method in foundation treatment scheme selection. Results show that the model can provide technically reliable and economically reasonable references for decision-making in soft ground treatment.