Wuhan Yangtze River ? Level Terrace Super-long Deformation Analysis Of Deep Foundation Pit Supporting Structure And The Parameter Study

In the past ten years,the length of wuhan metro area has reached 215.3km,and the speed of opening two lines is developing.In the process of subway construction,safety and economy are the two main factors,including economy accounted for in the supporting structure in the whole project is high,is also the most important line of defense security,therefore,through the analysis of deep foundation pit excavation of a master in the process of retaining structure deformation characteristics,has very important guiding significance.This paper,taking wuhan rail transit line 8,zhongnan hospital,based on a subway station at the same time,I participate in piling and?and?excavation process in the region and in the meantime,independently complete the retaining pile survey and steel support axial force measurements,data into the computer with USB interface,sums up its deformation characteristics,combined with the geotechnical engineering special finite element software modeling analysis,the main contents are as follows:?1?During the internship,to participate in the monitoring plan,and alone is responsible for the measured with inclinometer deformation of the retaining pile axial force,with a vibrating string type meter measuring steel strut axial forces,to import the data into the computer to form a journal,report and general supervision.The whole data is summed up,and the deformation law of the envelope and the change characteristics of steel support axial force are obtained.?2?The project of foundation pit is 625 m,is located in the Yangtze river and terrace?,geology change is bigger,combined with the finite element software,layered,subregional modeling,the largest extent,make model close to actual engineering,this article from the regional?actual monitoring data and software simulation data contrast,deformation trend line,the maximum and the minimum is slightly difference,prove the significance of this model in engineering.?3?On the basis of the model,the influence of space effect on envelope structure is discussed.Will be stepped excavation area?analysis,the deformation process with different layering excavation,retaining structure are local red,and the maximum value of 13.14 is stratified excavation maximum 16.7 mm is small,overall,although simplified stratified excavation,but also accords with the actual situation,so in most cases,for convenience,layering excavation directly.?4?Discussed two kinds of different excavation method,excavation and symmetrical excavation in sequence,from the perspective of retaining structure deformation,long the most reasonable use semmetry excavation of foundation pit,because in the whole process of excavation and symmetrical excavation retaining structure deformation is the smallest,relatively short exposure time and foundation pit,greatly reduce the project risk.?5?Select things end shield shaft hole Angle effect analysis,in the foundation pit short side direction,palisade structure space constraints,the role is more prominent,for this project,edge distance 10 m long,short distance over 6 m Angle effect will be weakened.?6?Combines orthogonal experiment and finite element,the pile length,pile spacing,pile diameter and steel support spacing of the four parameters were analyzed,and influence the effect of horizontal displacement of retaining structures from big to small order in the order:pile spacing,pile diameter,spacing and pile length.For this project,the optimal combination mode₄₁₄₂ is 26m,the pile diameter is 0.6m,the pile spacing is 2.0m,the support spacing is 4.5m,the maximum deformation is 24.75mm,and there is a certain safety reserve.