A Suitability Evaluation Data Structure and Its Generation Method for Urban Underground Space Development Based on an Improved Generalized Tri‐Prism Model

ABSTRACT Urban Underground Space (UUS) has been recognized as significantly important for the future sustainability of metropolitan areas. A fine, accurate, and efficient suitability evaluation has become a prerequisite and necessary means for the effective and rational development of UUS. As the evaluation methods transition from two‐dimensional to three‐dimensional and evolve towards greater refinement in three‐dimensional scales, the existing evaluation methods based on Grid + Voxel cells struggle to capture the scale differences of various geological factors and lack the requisite precision to represent the constraints of terrain, water bodies, buildings, faults, and karst features. In response to this challenge, this paper proposes a spatial partitioning method based on an improved Generalized Tri‐prism model for UUS Evaluation (GTP‐UE), which is utilized as the basic cell. The GTP‐UE model improves upon the limitations of the general GTP model in data structure while retaining its wide geometric applicability and strong maintenance scalability, allowing for simpler multi‐element recording, more efficient topology calculations, and faster collision detection, making it more suitable for UUS evaluation. This study first proposes the data organization format of GTP‐UE. Next, an optimisation algorithm for 3D Boolean operations based on the GTP‐UE model is presented. Finally, a case study is conducted in a specific area of Nanjing to verify and discuss the feasibility and advantages of the proposed technical approach. The results indicate that, in comparison to Grid + Voxel cells, the new evaluation method for UUS development based on the GTP‐UE model effectively considers the true representation of geological bodies and environmental characteristics, showing significant advantages in both computational efficiency and storage space during model generation. Evaluating the applicability of other irregular volumetric models in UUS evaluation and enhancing the Boolean operation efficiency in geometric models during multi‐indicator fusion are two worthwhile directions for future research.