## 5 Conclusions  
Considering the differences in spatial structure and modeling data between different modeling objects, such as the Quaternary loose sedimentary strata and bedrock strata, a unified modeling framework based on standard stratigraphic sequences was adopted. Specifically, global discrete point modeling and the global layered modeling were utilized for model construction. Without generalizing the modeling data and modeling objects, this approach addressed the technical challenges of efficiently and precisely constructing large-scale urban 3D geological models under the conditions of scarce and multi-source heterogeneous modeling data. By utilizing these modeling techniques, we can obtain detailed and accurate representations of the geological structures, which are crucial for various applications such as urban planning, disaster prevention, and engineering construction.  
The primary challenges in the current research on large-scale urban 3D geological modeling lie in the variations in modeling accuracy across different regions due to the uneven distribution of modeling data, as well as the issues related to model updating in later stages. Additionally, given the immense workload involved in modeling and the uncertainty associated with manual modeling, leveraging artificial intelligence to automate the modeling process will inevitably become a trend. Furthermore, considering the enormous volume of the large-scale urban 3D geological model, lightweight processing of the model and coupling it with the 3D surface model, as well as subsequent online publication and sharing, represent a key research focus for the future.  
The 3D geological structure model of Wuhan's MDA incorporates 26 strata spanning different geological eras, 195 faults of varying scales, and 37 folds with diverse origins. The comprehensive accuracy of the model is determined to be 83.6%. The quality of the model exhibits the lowest level around the periphery of the study area, a peak in the central region, and an overall trend of a gradual increase from the periphery towards the center.  
Conceptualization, J.Z. and L.Z.; methodology, J.Z.; software, J.Z.; validation, X.Z.; formal analysis, J.Z. and L.Z.; investigation, J.Z. and L.Z.; resources, J.Z.; data curation, J.Z. and L.Z.; writing--original draft preparation, J.Z.; writing--review and editing, J.Z. and L.Z.; visualization, J.Z. and X.Z.; supervision, X.Z.; project administration, J.Z.; funding acquisition, L.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the China Geological Survey Program, Land-Sea Coordination of Basic Geological Survey Results Integration and Expression of Key Technologies (No. DD20230416). Comprehensive Monitoring of Resources and Environment Carrying Capacity of Xiong'an New Area and Construction of Digital Platform of Transparent Xiong'an (Institute of hydrogeology and environmental geology, Chinese Academy of Geological Sciences) (No. DD20189144), 3D geological modeling of Multi-factors urban geology of Wuhan (No. WHDYS-2021-010), Research, development and promotion of digital collection technology for water resources surveys (DD20230427), and Operation, Maintenance and Network Security Assurance of Geological Survey Nodes on Cloud Platform (DD20230719).  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare that they have no conflicts of interest.