Theoretical Analysis And Numericial Calculation Of Retaining Structure With Double-row Piles

Double-row piles is a new type of composite structure for excavation. It is widely used by lots of people in the project for its advantages in controlling displacement, convenient construction and saving underground sPace. But there is some disadvantages limit its use,for example the stress of the structure is too complicated to get a relatively perfect calculation theory. The theoretical research of the Double-row piles is far behind the engineering application. Although some calculation models has been got, but it is not accepted mostly to describe the influence of the row sPacing, the beam stiffness, pile length and diameter. The calculation methods of the current national and area standard also have some limitations to use in engineering. The Paper has carried on further research and are shown as follows:Firstly, analyzed and summarized several typical calculating theories about the double-row piles. Point out its scope of application and shortcomings.Secondly, the Paper analyzes the influence of pile stiffness to the slip surface location, the starting point of the slip surface should be below the excavation surface of the foundation pit; And spring stiffness changes with the depth of the earth. A new calculation model is proposed combined with the slip surface morphology and earth pressure. According to the model the factor of the soil stiffness between piles is listed to analysis the bending moment and displacement on the pile.Lastly, use the finite-difference software FLAC3D to establish engineering model and carry on the numerical simulation to simulate the excavation on the initial engineering condition of the double-row piles retaining structure. Summarize the results when change the distance of the pile-rows and link beam stiffness respectively, analyze the results’differences and changing law. CoMPared the calculation effect of the theoretical model with the actual observation data, it is proved satisfactory result can be obtained with reasonable Parameters applied in the model.