Application Of Grey Theory Prediction Model In Deformation Monitoring Of Super-high-rise Foundation Pit In Ningbang

With the successful convening of the second session of the 13 th National People's Congress,Premier Li Keqiang pointed out in the government work report that the current tax reduction and fee reduction policies for the construction industry,transportation industry and other industries.China's urbanization construction industry has been further supported,and the high-rise buildings and deep foundation pit projects had shown signs of springing up.The construction of large-scale underground shopping malls,the basement of high-rise buildings and the construction of large-scale municipal projects were all facing deep foundation pit projects,which constantly refresh the record of the depth and scale of foundation pit engineering,and the safety of foundation pits becomes more and more important.For the work site,the new development trend needs new construction technology support.This hot issue comes from this.It was very important to study the development trend and safety of deep foundation pit deformation stability monitoring and prediction.This paper relies on the case of Ningbang super high-rise deep foundation pit project in Loudi City,Hunan Province.The monitoring point data in the construction process was obtained by SDL30 precision electronic level imported from Japan.The grey theory model was used to analyze the deformation data of foundation pit deformation as follows:(1)The system introduces the gray theory method and focuses on the GM(1,1)prediction model.By studying the mechanism of the traditional GM(1,1)model,the original sequence and background value structure were optimized respectively to establish an optimized GM(1,1)prediction model.(2)Based on the foundation pit engineering cases,the foundation pit deformation monitoring program was analyzed.The layout,monitoring frequency,monitoring alarm value and observation procedures and steps of monitoring points are studied,and the measured values of monitoring points were analyzed to master the deformation characteristics of foundation pits.(3)Based on the monitoring point instance data,combined with MATLAB calculation software programming,the traditional GM(1,1)model and the optimized GM(1,1)model were used to compare and analyze the monitoring points,and the residual qualified model and the small error probability were qualified.The model and the mean square ratio qualified model were tested for accuracy.(4)Aiming at the large error or omission of the original sequence of the monitoring point,the prediction accuracy of the model was not high.A dynamic GM(1,1)model based on Lagrange correction was proposed.Based on the engineering example,combined with the traditional GM(1,1)model for research and analysis,the results show the reliability and accuracy of the dynamic GM(1,1)model modified by Lagrange.