Stability And Deformation Analysis Of Mixing Pile And Prestressed Soil Nail Composite Supporting System

Soil nail supporting is broadly used in underground engineering, especially used infoundation pit because of its numerous advantages such as fast construction, economicsecurity and so on. However, the generalization of soil nail is limited by itself appliedconditions. Since composite soil nail supporting has been gradually used in retaining andprotecting for foundation excavation, practice has showed its economic advantage.The mixing pile & prestressed soil nail composite supporting system, a common andeffective method of composite soil nailing supporting, can control the deformation offoundation ditch effectively and improve the stability of earth slope greatly. But the behindschedule theories study obstruct its further development. Thereby, this paper, base on theactual research condition and practical engineering requirement, analyze the stability,mechanism, deformation of the mixing pile & prestressed soil nail composite supportingsystem by study of theories, field test and numerical simulation. Main study content asfollows:1) Give the stability analyze method of composite soil nail. This method introduce fourdestruction types, analyse each working mechanism, and their calculation methods aregiven.2) Study the reinforce mechanism of soil nail.With result of the pull-out test of soil nail,it analyse calculation mode of internal force of soil nail in different situation and provide theformulas.3) Generalize three main calculation modes of surface soil pressure and their defect inpractice, point out the mechanism character of reinfroce surface of. mixing pile4) Combind with the foundation excavation project of Guangzhou Panyu HolidayHotel, it studies performance of composite soil nail in constructing and working situation byanalysing the result of field test, such as the loading of soil nail and deformation offoundation fit.5) Establish three-dimensional finite difference model to simulates constructionprocess of the deep mixing pile & prestressed soil nail composite supporting system withFLAC3D software. Furthermore, it compares the result with practical monitoring data toindicates the working mechanism of composite soil nail system and obtain exact simulationand forecast of deformation of foundation excavation.