Deep Foundation Excavation Close Neighbor Of Bridge Piles

Bridge piles response to nearby deep excavation in soil is a vital project, which is also one of main research contents about disturbed soil,environmental theories of stability as well as controlling methods. Based on the former study and the actual situation of deep foundation pit excavation of Beijing metro, the coupled action of which retaining structure, soil and bridge piles is synthetically considered in this paper. This project is examined in detail by 3-dimensional fast lagrangian method. The main contents of this thesis are as follows:1,By in situ monitoring test, the research on the deformation of deep foundation is made, to which the information reflection responded is analyzed. The rule of bracing force changed the deformation of piles in row and protecting piles, the distribution of earth pressure between piles in row and the soil around, and the settlement of bridge piles are mainly analyzed.2,Based on 3-dimensional fast lagrangian method, the numerical model of the influence of the process of excavation and support of foundation pit on nearby bridge piles is created, in which the research of the influence of the extent of inherent bracing stress, the depth of excavation and the stiffness of retaining and protecting for foundation excavation on nearby bridge piles is made in detail. Then the actual measurement data and numerical calculation data are analyzed by contrast.3,Making research and analyzing the space distribution character of deep foundation deformation and the distribution rule of the displacement of the surrounding stratum, and the influence of deep foundation excavation on nearby bridge piles is done.Based on the former study, the main conclusions acquired are as follows:1,The influence of the inherent bracing stress and the excavation step on horizontal displacement of nearby bridge piles is the most, of which the stiffness of piles in row is secondary, and of which the stiffness of protecting piles and the steel bracing is the last. while the inherent bracing stress can't change the horizontal displacement of the bottom of bridge piles as well as that of the top.2,As the depth of deep foundation pit increases, the horizontal displacement behind the protecting piles integrate at the top of the bridge piles and the protecting piles, while the distribution of the horizontal displacement without piles is open, of which under the bottom plane is symmetrical.