An Information Modeling and Dynamic Updating Method for Railway Station Complex Subgrade

Abstract

Building Information Modeling (BIM) plays an important role in the modernization of transportation infrastructure. Its core is to accurately describe the characteristic information of engineering structures and to achieve the real-time update of the dynamic changes in the design process. As an important part of traffic infrastructure, the subgrade is a kind of earthen structure composed of layered Filler-Layer, Filler-Area and Subgrade-Body, with distinct hierarchy characteristics. Meanwhile, there is a highlycoupling among the Filler-Layer, Filler-Area and Subgrade-Body. Any modification will cause the adjustment of the related part. How to accurately describe the hierarchy, the coupling characteristics and always maintain the consistency among Filler-Layer, Filler-Area and Subgrade-Body in dynamic adjustment is a major problem that has long plagued subgrade BIM research. Especially the railway station subgrade, which bears a variety of equipment, includes a large number of Subgrade-Body, Filler-Area and Filler-Layer. Unfortunately, the current description of the hierarchy and coupling for such complex subgrade is not completed, and it is difficult to realize the dynamic update of the coupling within the complex subgrade. In order to solve this problem, this paper defined three subgrade-components: the Subgrade-Body, Filler-Area and Filler-Layer.Firstly,a four-level R-tree topology of " Cross-Section → Subgrade-Body → Filler-Area → Filler-Layer " was constructed, anda hierarchy coupling subgrade information model was designed based on the fusion of directed graph and R tree, the hierarchy and coupling are described. Finally,the judgment criterion and reconstruction algorithm of the subgrade minimum influence region are proposed to realize the automatic update of the information model. Based on the above methods, the BIM design system of railway station subgrade has been developed, and the design and construction of various complex station subgrade have been completed. The application results show that the BIM model established by this method can accurately describe the hierarchy coupling characteristics in the subgrade, and can automatically maintain the hierarchy and coupling during the design process, dynamically update the associated subgrade-components, and significantly improve the design efficiency and quality.