Research On Safety Assessment Method Of Deep Foundation Pit Based On Monitoring Data Analysis

With the rapid development of national economy,more and more engineering construction involves deep foundation pit construction.The deformation of deep foundation pit is a process that changes gradually with the construction progress,and the monitoring data can directly reflect the stress and deformation of rock mass in the corresponding position.Based on the monitoring data analysis,it is of great engineering value and scientific significance to accurately predict the deformation trend of deep foundation pit,and then timely understand the safety state of the whole project.Based on a deep foundation pit project in Shenzhen,this thesis comprehensively considers the monitoring data of different types and different positions,and researches on the deformation trend prediction and safety assessment of deep foundation pit engineering are carried out.The specific work is as follows:(1)Relying on a deep foundation pit engineering construction project in Shenzhen,based on the field test and collection work,the system This paper expounds the design of monitoring scheme for deep foundation pit engineering,and digs out the deformation laws of various monitoring items by drawing the deformation curves of time data.At the same time,the piecewise linear interpolation method is used to interpolate the original monitoring data,and the wavelet transform technology is used to decompose and reconstruct the deformation data.(2)Deformation prediction method in view of the existing stability problem,the forecasting accuracy is not high,on the basis of monitoring data sequence pretreatment,using genetic algorithm(GA)to the key parameters of support vector machine(SVM)to carry on the optimization,set up automatic regression moving average algorithm based on wavelet transform(GASVM-ARMA)one step and multiple step rolling forecast model.Compared with the prediction results of GASVM model,it is found that the combined model has higher prediction accuracy and stronger applicability to nonlinear problems under complex conditions.(3)For deep foundation pit safety assessment quantitative problem,lack of system,based on spatial interpolation technique to extract the representation of the deformation monitoring data,puts forward an improved entropy weight-hierarchical analysis and fuzzy comprehensive evaluation model,and according to the new division of safety state evaluation index,level 5 from the Angle of the weights of different types,different parts of the monitoring data of holistic consideration objectively,The stability of deep foundation pit is studied.The feasibility of the proposed method is verified by the practical engineering safety evaluation and comparison.(4)Based on MATLAB-GUI platform,a set of safety evaluation system for deep foundation pit engineering was developed,which realized the visualization of deformation prediction and safety evaluation process.The results of prediction and evaluation could be displayed in the form of numbers and pictures,which was helpful for the analysis and decision of safety managers.