Highway Vertical Alignment Design Process Model Based On Design Constraint Information

Highway design can be described as a reflection of the particular pattern of constraints which make up the problem.The design constraints of vertical alignment mainly include geometric standard constraints and elevation control constraints.At present,the constraint satisfaction of highway design software is post evaluation mode.In the design process,due to the ineffective integration of constraint information,the designer received limited support.Due to the low level of design software support,the efficiency is low.The paper proposes to integrate BIM(Building Information Modeling)+ GIS(Geographic Information System)to establish a hydrological analysis model of highway area supported by GIS and a fast earthwork estimation model supported by BIM.This paper studies the expression of design knowledge based on rules,transforms design constraints into feasible region with the help of graph theory,and then establishes the process model of vertical alignment design based on feasible region,so as to improve the decision-making information support level in the design process.In the process of vertical alignment design,the location of bridges and culverts and the design elevation are important control conditions.The paper establishes a hydrological analysis model of road area,and divided it into five stages: DEM(Digital Elevation Model)establishment,DEM preprocessing,water flow direction calculation,flow accumulation calculation,and reach network extraction.The paper establishes the road area DEM based on the triangulated irregular network(TIN)generation algorithm and the grid interpolation algorithm,realize the DEM preprocessing based on the J&D algorithm and the elevation incremental superposition algorithm,complete the flow direction and cumulative flow calculation based on the D8 algorithm and the Dinf algorithm,and based on the threshold filtering method extract runoff network objects as the basis for determining the location and design elevation of bridges and culverts.Based on the hydrological analysis model of road area,the paper proposes a spatial reasoning-based alignment and hydrological element relationship model,and establishes a small bridge and culvert constraint recommendation model based on a knowledge framework.Based on the Civil 3D platform,a fast estimation model of earthwork volume was developed to lay the foundation for establishing the feasible region of vertical alignment design.According to the characteristics of vertical alignment design,the paper puts forward the idea of transforming design constraints into feasible regions,and designs a process model of vertical alignment design based on constraints.Drawing on the idea of graph theory,the paper establishes the graphic description model of vertical alignment design constraints,and realizes the graphic description of constraint information in design process.Based on the platform of civil 3D(BIM)+ Map 3D(GIS),this paper develops the hydrological analysis module,design constraint information support module and design feasible region module,which realizes the hydrological analysis,design constraint integrated management and design constraint graphical functions respectively.The research results of this paper integrate BIM + GIS technology with the design process,and improve the information support level in the process of vertical alignment design.