Research On The Theory And Method For Prediction Of Pile-Raft Composite Foundation Settlement Process

Our country is in the stage when high-speed railways develop rapidly. In the construction process of high-speed railway, control of settlement of subgrade is one of the most crucial technical measures.So we must guarantee the quality of subgrade in the construction process and master the real-time change of subgrade settlement. It would be best to estimate the accurate change reasonably. Then adjust and determine the construction time of subgrade and all structure layers, or take effective measures timely to avoid larger subgrade settlement which may result in serious consequence. These issues have become hot topic in the high-speed railway construction. In the current or future high-speed railway construction, there will be more poor foundations such as crossing the soft soil, so it’s urgent to attempt to resolve technical problems of subgrade settlement.The measured data of the pile-raft composite foundation settlement test is used in this paper for numerical analysis and calculation,Ⅰ apply these data to predict the pile-raft composite foundation settlement and study the forecast method of the pile-raft composite foundation during subsidence in order to provide experience and recommendations for future similar project and put forward a proper forecast method for reference.For realizing information construction better,the main research content of this paper are as follows:1.Level gauge,settlement plate,layered settlement gauge,profile sediment-tube and pore water pressure gauge,etc are used to settlement monitoring of the subgrade on site.2.Using various existing methods to predict the pile-raft composite foundation settlement based on the measured data,then making a comparative analysis.3.Selecting the embankment fill period and the dead load period settlement data of the pile-raft composite foundation in Jinan west railway station,Beijing-Shanghai high-speed railway to predict the pile-raft composite foundation settlement deformation in different stages respectively,then comparing the calculation results with the measured values.4.Exploring the pile-raft composite foundation settlement regularity during foundation pit dewatering and selecting a proper method to forecast and analysis. 5.Obtaining the best prediction method at different stages through comparing a variety of prediction methods.6.Calculating the residual ground settlement through the obtained method.