The Foundation Pit Deformation Prediction Model Research And Engineering Applications

With the rapid development of social economy and urban construction,the deformation prediction of deep foundation pit construction has become one of the substantial issues of geotechnical project.The thesis focus on deep foundation pit construction,aiming at the difficulties and problems of in-situ monitoring of deep foundation pit monitoring and deformation prediction,and carry out a relatively profound research of deformation prediction technology in deep foundation pit construction by introducing in Grey GM(1,1) Model;BP Neural Network Model,and Grey System--BP Neural Network Combination Model.The main contents are as follows:(1) Make out a comprehensive summary of status quo of the safety monitoring system of construction foundation pit,point out the existing problems and deficiency,on that basis,integrate with the latest research product the status of the development of prediction instrument and working experience,(2) Introducing the Grey theory,integrate the characteristic of deep foundation pit construction,build the ameliorative deep foundation pit Grey GM(1,1) Prediction Model.Project examples,demonstrate such advantages of it as few necessary sample data,high prediction exactness and simple calculation process(3) Choose a monitoring point to do analytic study about degree of association,if the fact of the project shows the prediction is well,then it can be used in safety monitoring system to predict the deformation trend of correlative monitoring point,through which can reach an aim of saving costs as well as working time.(4) Induct and build deep foundation pit Grey System--BP Neural Network Model which is more accurate than Grey GM(1,1) Model. Improve and extend the mistake tolerating capacity,and automatic adapting and learning function of deep foundation pit deformation model.(5) By combining the individual advantages of Grey GM(1,1) Model and BP Neural Network,build Grey System--BP Neural Network Model,and solve the model through MATLAB Programs so that the model can obtain relatively high prediction exactness even in the face of data sequence with "few samples" and "few data".(6) On the basis of monitoring data of foundation pit in Yantang Station, Line 3 of Guangzhou Subway,the author tests the model built,and puts forward the conclusion and the outlook.Use the deformation prediction model to predict the deformation of space enclosing structure of foundation pit and the peripheral solum of deep foundation pit construction in Yantang Station,Line 3 of Guangzhou Subway,by comparing with the surveying result on site,the models built in this thesis demonstrate high reliability and wide applicability.