The Research On Optimization For Support Scheme Of Deep Foundation Pit

Deep foundation pit engineering is a system engineering which has the characteristics of synthesis,danger and so on.The choice of the supporting system of the deep foundation pit has a direct impact on the quality,cost and schedule.Choosing a reasonable supporting system plays a decisive role on ensuring the safety of the foundation pit,underground structures,the building and underground engineering near the foundation pit,meanwhile,it Lays the foundation for the successful progress.Therefore,it is very necessary and meaningful to find a scientific and perational way of selecting the supporting system of the foundation pit.The essence of the optimization of the deep foundation pit is to consider the decision problem of multi objective.Therefore,we can reach the goal by Multi-target Deeision Method.Based on the research status of deep foundation pit and the Multi-target Deeision Method,this paper puts forward a systematic model of selecting the supporting system of the deep foundation pit.(1)Collecting and analyzing relevant information,determining the Foundation Pit Safety Grade and the Deformation Control Grade according to the actual engineering situation and related specifications,then completing the primary election of the system;(2)Setting up the target hierarchy and the Evaluation System by using the Analytic Hierarchy Process,meanwhile achieving the evaluation results by the expert evaluating method,then obtaining the Index weights by Constructing the judgment matrix.(3)Seting up the factors set,the evaluation factors and the fuzzy conversion matrix,and finally obtaining the quantitative evaluation results according to the weight of each index factor and the fuzzy comprehensive evaluation;Combining with an engineering example,optimizing the supporting system of the Beijing Rong Kun Pension Center through the application of this model,and vcalculating and analyzing the related parameters by the Li-zheng deep foundation software.The result shows that the model is scientific and reasonable,and it can provide some practical significance for reference in the similar foundation pit engineering.