Safety Evaluation Of Deep Foundation Pit Based On Improved Attribute Reduction And BIM Secondary Development

In recent years,with the development of urban underground space engineering in China,the scale of foundation pit is developing towards deep and long direction,in order to ensure the safety of foundation pit,foundation pit monitoring is essential.How to comprehensively analyze the monitoring data and visualize the safety risk of foundation pit has important research significance.Although the existing fuzzy comprehensive evaluation method can be used to evaluate each monitoring index,it has some shortcomings such as strong subjectivity.In this paper,based on improving attribute reduction,information entropy theory is used to improve the existing fuzzy comprehensive evaluation method,which greatly reduces the subjectivity of this method;In addition,in order to realize the organic unity of foundation pit model and monitoring data as well as foundation pit safety risk evaluation,based on BIM secondary development technology,Visual Studio 2019 and Autodesk Revit 2016 as the development platform,using C# and SQL as the system development language,taking the foundation pit monitoring data file and network import as the starting point,the function plug-in of the foundation pit monitoring data visual display is developed to realize the organic combination of foundation pit monitoring data and foundation pit model.On the basis of determining index weight by improved attribute reduction,the traditional fuzzy comprehensive evaluation method is improved and the deep foundation pit safety evaluation system is developed,the system has good data management and visualization ability and the embedded fuzzy comprehensive evaluation method based on improved attribute reduction is adopted,therefore the management of monitoring data,visualization of monitoring results and comprehensive analysis of monitoring data in the process of deep foundation pit monitoring are realized to evaluate the safety characteristics of foundation pit.The main research contents and achievements of this paper are as follows:On foundation pit safety risk evaluation,the paper summarized the related theories,in order to solve the problems about foundation pit monitoring indicators such as excessive reduction,low reliability,excessive reduction results and undetermined weight,on the basis of traditional fuzzy comprehensive evaluation method,improved attribute reduction algorithm is proposed based on rough set conditional information entropy and the intensity of decision theory and combined with the traditional fuzzy comprehensive evaluation method,the index weight determined by the improved algorithm is more objective than the original weight,avoiding the subjectivity of the assignment.Summarized BIM technology related to Revit software and related technologies of secondary development,followed the ideas of data import,intuitive data analysis,comprehensive data analysis and evaluation,developed a deep foundation pit monitoring and evaluation system based on BIM technology.The functions of the system include basic single index monitoring,improved fuzzy comprehensive evaluation method of foundation pit overall monitoring,monitoring visualization,efficient monitoring management and other functions,the monitoring and evaluation system not only obtains monitoring data for foundation pit monitoring,but also gives Revit software the ability to calculate and process complex data.The improved attribute reduction algorithm proposed in this paper and the foundation pit monitoring and evaluation system developed are applied to the foundation pit monitoring of a residential building in Qingdao,and the results show that: The monitoring and evaluation system can not only deal with the relatively simple single index monitoring,but also support the overall monitoring of foundation pit with complex calculation,the efficiency of foundation pit monitoring is significantly improved and the labor cost is reduced,in addition,the system also realizes the efficient management and visualization ability of the monitoring system,the efficient management of the monitoring system is reflected in the smoothness and usability of system use,data storage,data query,data change and other operations,while the visualization ability of the monitoring system is reflected in the display of single index monitoring results and historical monitoring data.