The Research On The Settlement Of Group Piles In High-speed Railway Bridges

As the need of the traffic increasing rapidly, it has been a great task for ourcountry to develop our high-speed railway.The settlement of the foundation in high-speed railway is controlled very strict. In the meantime, the bridge section in itaccounts for a considerable proportion.Thus the research on the settlement of thegroup piles is of great significance to the construction of high-speed railway. It is notonly one of the important references for bridge design and construction, but also animportant index of ensuring the safe operation of the high-speed railway.There are somany traditional calculation methods for the settlement of group piles, but most ofthem are not accurate because of the problems below：(1) The influence of the totalshear stress of the soil on the side of group piles are not considered and the methodswhich they use to calculate the settlement of the deep and shallow foundation are thesame;(2) It is not tally with the actual situation as it has not considered thecompression deformation of the soil between the group piles;(3) The settlementcaused by creep deformation of the foundation are not considered.In this paper, the author has done the works below based on the measured data ofthe group piles which belong to Deng jiawan bridge in Chengyu high-speed railway.At first, some corrections have been done to the equivalent substitution method intraditional calculation methods. In this work, the influence of the total shear stress ofthe soil on the side of group piles and the settlement caused by creep deformation ofthe foundation are both considered. Then ANSYS finite element software is used tosimulate the settlement of group piles. At last, based on the work above, thecalculation for creep settlement of the foundation is done by building models.The result shows that：(1) The modified equivalent substitution method considersmore and the result of it is more accurate,but it still has a gap with the measured data;(2) The method of building models by ANSYS which has no consideration offoundation creep can simulate the settlement of group piles good, and the result of itis close to the measured data but not accurate enough, that shows it is very necessaryto consider the foundation creep when we need the accurate results.(3)The method of building models by ANSYS which has a complete consideration of the foundationcreep is more accurate, the accuracy can reach95%;(4)The methods which putforward by the author have some certain reference value for engineering calculation.