Application Research On Pile-anchor Supporting Structure Analysis And Evaluation Method Of Deep Excavation

The design demands of supporting structure for deep excavation of the city center arebecome more and more strict. Because the pile-anchor supporting has the superiorcharacteristics such as simple construction、good slurry-supported effect、big constructionspace、security and stability, so it has been used widely in deep excavation. Pile-anchorsupporting made full use of the row pile and the prestressed anchor, and it made supportingstructure stress more reasonable and the construction of deep excavation became more andmore safety and reliable. But as a new type of retaining structure, the structure calculationmethod and scheme evaluation method needed further research. According to the existingshortage, the thesis mainly studies from the following several aspects:At the first, it expounded the calculation theory and calculation model of the earthpressure role in the pile-anchor supporting and then studied the elastic foundation method andthe elastic ground rod finite element method of single protection and much protectionstructure for pile-anchor supporting. Based on the research, it studied the programmingprinciple of the Lizheng deep excavation software, and then introduced the influencerelationship for the the interal forces and deformations to different stiffness of anchor or cableby using the software., and we found that the accuracyvalue of anchor’s stiffness has largeinfiuence for the internal force and displacement of the support structure.Secondly, in order to learn more about the influence of supporting structure for anchordeformation characteristics, according to the character which the free segment can also takepart of load when it grouted full, it introduced the double line model which can reflect thestrength attenuation of the soil anchor interface. Based on the theory of load transfer andenergy principle in value, it study the carrying deformation properties of prestressed anchorconsidering load on the free section.Thirdly, according to the fuzziness and incompatibility of the scheme evaluation indexfor excavation support scheme, it can use the fuzzy matter-element optimization theory tosolve the problem and establish the matter-element evaluation model for general excavation.Based on the characteristics of pile-anchor supporting in the city center we determine its mainevaluation index and do the optimization evaluation for the Huayuan deep excavation whichlocated in business circle of Changsha city.Finally, based on the Huayuan deep excavation engineering, the research results areapplied in the deep excavation engineering and the rationality and practical of theoretical are reflected by the field monitoring data and the engineering effect.