Deep Foundation Design Of Double-row Piles Retaining Structure

Retaining structure with double-row piles is a new type of supporting method which emerged in recent years,the structure can be understood as part of the original concentration of single pile pile move back a certain distance,formed the two rows of parallel piles,and even the beam on the top of the pile with crown beam of gantry framework supporting structure.As a kind of space combination type structure,its outer loads can automatically adjust the internal force of structure itself,make it adapt to the complex and changeable and unpredictable load condition,reduce the horizontal displacement of supporting system,thus retaining structure with double-row piles has been more and more widely used in engineering.This article is mainly combine about a residential housing and underground garage excavation works of Langfang City,Hebei for an engineering example,to double-row piles retaining part of the excavation for the study,analyzed the double-row piles diameter and the pile spacing for double-row piles retaining structure on the settlement,displacement,shear forces,bending moments as well as the safety factor and the like,based on the location of the project geology,engineering profiles,etc.Through the design and optimization,and strive to get the best design scheme,to provide some useful reference for retaining structure with double-row piles in construction of foundation pit supporting in the future.The research achievement for this article is:(1)Based on the characteristics of deep excavation engineering,development status at home and abroad as well as pit support form the main characteristics and issues,analyzed the characteristics of double-row piles supporting structure,the structure and form of the pile cloth advantages and disadvantages,and summarized calculation double piles retaining structure system.(2)Based on the actual project of Langfang City,Hebei,analyzed the program of double-row piles bit part and optimized a part of the program parameters,to meet the specification requirements of the premise,taking into account economical and convenient construction principles,and to satisfy the optimal solution.(3)The internal force,the strength and the deformation of the structure are analyzed,and the stability of the structure is checked.The design of the pile,crown beam and coupling beam in the selected optimal scheme is analyzed.(4)Monitored for the foundation pit design,and expounds the matters which should pay attention to,such as the frequency of monitoring,early warning value,and the calculated results and monitoring results are analyzed and compared,verified the effect of the design of the optimal solution.