Based On FLAC~3D Numerical Calculation Of The Composite Pit Retaining System With Anchorage Pile And Composite Soil-nailing

Recently , the support method of combining soil nailing in the upper part and row-piles in the lower part with anchor(the combined support structure of pile-anchor and soil nailing)has been widely applied to pit support of edifices in cities , where people demand cheap and safe constructions while the facilities become more and more complex, for example the area , gas, water , electricity piles and roads. The shallow grading of upper part is supported by soil nailing(because of the price).While in the suburbs of the lower part, water is shut off by mixed pile and row-piles & anchor are retaining support in the inner part(so the construction area would be limited to the smallest). Meanwhile, because people only know some of the study on combined support structure of pile-anchor, it is still the primary stage to learn the support's mechanism and coordination. Therefore this paper conducts the three-dimension numerical analysis method in the mechanism study of the combined support structure of pile-anchor and soil nailing on the project of Guangzhou Jiangnan New Garden.In the paper, we take a Guangzhou pit project as an example and establish finite difference analysis model of spatial three-dimension by finite difference software of the FLAC3D program. By numerical modeling three dimension regime in the combined support structure of pile-anchor and soil nailing system, we find that the method is practical because both of the answers are almost the same by calculating and actual exploration.When studying the horizontal displacement,vertical displacement and pull force of the pre-stressed anchor's of the support structure, we also explore the rules of the plasticity area of the soil during the stepped excavation of the pit and get some useful conclusion of the design and construction of pit projects.This conclusions of the study could offer some suggestions to project designs and constructions and give some information of numerical simulation modeling to others.