Reuse Modeling And Optimization On Construction Technical Plan Of Deep Foundation Excavation Of Metro

Metro construction has become a complex high-risk activity.The occurrence of accidents has both objective factors such as complex construction environment and subjective ones such as lack of construction plans or irrational plans.The special safety plan is an important textual document that guarantees construction safety.The special program preparation for a new project is a complex knowledge-intensive activity with the features of wide coverage,complicated technical system,and higher requirements for experience-related knowledge.The demand for past and valuable program knowledge in the special program preparation is particularly strong.Therefore,from the perspective of knowledge management,this paper uses Case-based reasoning,Bayesian networks,and multi-objective optimization method to express,reuse and optimize based on the safety special program knowledge to support the formulation and optimization of special safety programs for new construction projects.The research content is as follows:(1)Knowledge expression method for special safety plan.The special safety plan of deep foundation pit in metro station is complex multi-dimension information.Firstly,it proposed the requirements of reuse-oriented knowledge information modeling to build the principle and criteria based on the demand analysis.Then,special schema is organized and expresed by using knowledge elements.Finally,a framework model based on knowledge elements was developed under the purpose and principles of knowledge information modeling,which provides a foundation for the next step of the special program reasoning.(2)Knowledge information reusing method of the special safety plan for risk control.Several important parameters affecting case retrieval were optimized.Firstly,considering the uncertainty of the special plan,the interval type-2 fuzzy set method was adopted to express the indefinite characteristics of the project attributes more realistically.A similarity integrated calculation method is proposed,which avoids the traditional numerical unified transformation and the information loss and inaccurate results caused by using a single function to calculate the similarity.Then,based on the different impacts of search cases on new engineering cases,this study proposed an improved k-nearest neighbor case retrieval method in terms of the idea of feed-forward kernel function.By defining the program's security index,the effect on weights of the feed-forward retrieved case on the new case were presented,which support the retrieval of optimal and most similar case searches.The retrieved case will support the development of the safety special program.(3)A dynamic optimization method of safety measures in the special safety plan based on construction site.Safety measures,as an important part of a special security program,have significant time dimension characteristics.A Bayesian network model for risk factors and risk events is systematically constructed,which explains the mechanism of safety accidents and identifies the key factors.The causality matrix of risk measures and risk factors is proposed and risk assessment can be conducted.The decision-making process in the implementation of safety measures is systematically analyzed,and four factors influencing the decision-making are obtained: risk control,inherent risks,cost of measures,and duration influence of measures.A multi-objective optimization model that satisfies the requirements of the safety and anti-risk ability in the construction site is proposed.Genetic algorithm is introduced to obtain the optimal solution of the model to support the dynamic optimization decision-making of the special security program.Relevant decision-making models and methods in knowledge management are applied throughout the process of formulating and optimizing specific security programs for deep foundation excavation.It hopes to provide good methods for the formulation and optimization of the specific security plan.More high-quality specific security programs help to better guarantee the safety construction of deep foundation pit at metro stations.