Subway Tunneling Induced Three-Dimensional Ground Surface Settlement Prediction Theory And System Development And Application

The ground moves and deforms while the construction of subway tunneling,due to ground loss and construction disturbance.There will be incline and cracks on the building when the differential settlement is too large.Therefore,the prediction and control of settlement is one of the main issue in underground engineering,and is of great importance in guaranteeing the safety of construction and people,s lives and property.Taking the shield tunnel of Beijing subway Line 7 Dougezhuang Station to Heizhuanghu Station,Heizhuanghu Station to Wanshengnanj iexikou Station,Wanshengnanjiexikou Station to Yunjingdonglu Station,and Line 8 Dahongmenqiao Station to Heyi Station,Tianqiao Station to Yongdingmen Station,and PBA station of Line 6 Liaogongzhuang Station as the in-situ research sites,the author made an in-depth study of the theory and application of settlement prediction.The main work and conclusions are as following:1.Theoretical study of settlement prediction considering the non-uniform deformation of the tunnel(1)According by the study of different ground deformation modes,a non-uniform tunnel deformation mode containing three different modes is proposed.A model for predicting ground surface settlement considering the non-uniform tunnel deformation is established by combining the stochastic medium theory.(2)The influence of the tunnel deformation parameters(the relative convergence,the relative ovalization,the relative vertical movement)on settlement trough is considered.The results show that the settlement trough of non-uniform tunnel deformation is narrower and deeper.(3)Back analysis on the tunnel section of Beijing Subway Line 8 from Dahongmen Bridge Station to Heyi Station is presented.The predicted settlement trough calculated with the deformation mode in this paper is better than the other two.The empirical values of the parameters are obtained.2.Theoretical study of settlement prediction considering time effect of settlement(1)A new settlement-time model is proposed.This model is based on normally distributed cumulative function.Taking the Beijing subway Line 7 Dougezhuang Station and Heizhuanghu Station section tunnel as the in-situ research sites,a case study has been performed,proved the feasibility of this method.(2)Based on the settlement-time model in this dissertation,a three-dimensional settlement prediction model is built up.We can make predictions of the spatial distribution and time variation of settlement based on measured data by using this model.(3)A method to compute the three-dimensional incline and curvature considering time effect is proposed.Thus the dynamic evaluation of differential settlement and the shape of settlement surface is possible.The results may be reference for subway construction.3.The probability method in settlement prediction based on improved Bayesian Dynamic Model(1)The method of using Bayesian Dynamic Model to predict ground settlement is proposed.Taking the Beijing subway Line 7 Heizhuanghu Station and Wanshengnanjiexikou Station section tunnel as the in-situ research sites,a case study has been performed,proved the feasibility of this method.(2)In the prediction of settlement by using Bayesian Dynamic Model,the predicted results can be corrected by the measured data continuously,thus a real-time prediction is made.(3)The method of using measured data to correct the error variance is proposed,the discount constant Bayesian Dynamic Model is improved.The predicted settlement is more close to the measured data after the improvement.The prediction accuracy is increased.4.Development and application of a Browser/Server based settlement measurement and prediction system.(1)A settlement procedure with 3 steps is proposed.Step 1,taking the settlement prediction model considering the non-uniform deformation of the tunnel for the preliminary prediction.Step 2,taking the three-dimensional settlement prediction model considering time effect for the dynamic prediction and analysis.Step 3,taking the settlement prediction model based on improved Bayesian Dynamic Model for the improvement of the previous predictions.(2)A Browser/Server based settlement measurement and prediction system is developed in this dissertation,called STEAD-Web,which is written by the programming language of C#/JavaScript/HTML/Python.(3)STEAD-Web is applied in the shield tunnel of Beijing subway Line 7 Wanshengnanjiexikou Station to Yunjingdonglu Station,Line 8 Tianqiao Station to Yongdingmen Station,and PBA station of Line 6 Liaogongzhuang Station.There is a good result of the application.