Experimentalanalysis And Numerical Simulation Study On The Deep Foundation Pit With Pile-Anchor Support

In recent years the rapid development of urban construction, foundation pit engineering will be used wider and wider. And the pile anchor supporting, with its unique advantages, is applied more and more in excavation supporting work. However, there are still many problems in engineering applications, such as the theory lags behind the engineering practice, in view of the above, studies on force and deformation of pile-anchor supporting structure are of great significance in the improvement and development of foundation pit theory.Take the 12th Street of Zhujiang foundation pit in Qinhuangdao as an engineering background to study the pile-anchor supporting structure in deep foundation pit. To carry out the field tests and numerical simulation analysis for the force of supporting piles and anchor as well as the lateral earth pressure with different conditions for the foundation pit, the main research work is as follows:(1) Through analyzing the field measured data, we obtained the changes of pile lateral earth pressure, pile stresses, bending moment, anchor force and deformation during excavation. It is shown that the lateral earth pressure changes dynamically during the excavation and its value is bigger in the middle than the one in the upper and lower position after excavation. The pile has the maximum of bending moment near the second floor of the anchor, while gains the zero bending moment at the upper part in pit bottom. Along the length of the anchor, its force goes down gradually and appears the largest change in the free section. There is a certain range of pull off areas in anchor segment by experiment.(2) Using finite difference sotware of FLAC3D to do the numerical simulation studies to the soil and foundation support structure, then research the soil stress, soil displacement, the force and deformation of pile and anchor with different depth of the excavation, and verify the existence of a range of anchorage section of the pull off area. Comparison between this result and field experimental data has been obtained internal force distrihution of soil and supporting structure.Interal forces and deformation distrihution of supporting structure are obtained by field tests and numerical analysis provided a theoretical basis for actual project of the future design and construction in the region.