Numerical Simulation On Combined Supportiong System Consisting Of Pile-interal-struct And Soil Nailing

Along with the development of the technology of the excavation of foundation pit,people have higher requirements of foundation pit,the traditional form of foundation pit excavation is no longer able to meet multiple objectives and requirements,more and more new forms of supporting began use in the foundation pit. The pile soil nailing support joint retaining structure which combine the supporting structure in supporting pile and soil nailing supporting structure in the excavation effect has proven to be very successful.However,the related theoretical study has lagged so far behind in engineering practice.The crucial problem to research the combined support is to study the working mechanism of the co-operation between them.Through introducing the soil arch theory,this paper discusses the earth pressure of retaining of the distribution transfer mechanism between the two forms.Through the use of the finite difference program FLAC3D to simulate the application of foundation pit engineering in the form of supporting,we obtained the stress and deformation characteristics of the global working mechanism of retaining structure and the various structural elements and soil pressure distribution mode during the excavation step. The main achievements made in this paper include:(1)This paper take the form of a joint approach and application of principles in summary the working mechanism of pile retaining structure and soil-nailing retaining structure;(2)For the horizontal form of association,through introducing the theory of soil arch,study the transmission mechanism and the working mechanism of retaining which soil pressure part of soil nailing support by soil arch support to deliver within the pile soil pressure retaining part of along with the excavation pit slopes downward and the advantage of sliding surface downwards moving backward;(3)The whole supporting structure is divided into five regions which is designed calculation respectively after the formation of the soil arch;(4)By using finite-difference program FLAC3D to simulate the application of foundation pit engineering in the form of supporting. Through the analysis and finishing of the result of the foundation pit which have been using this form,the vertical displacement,horizontal displacement of the laws and the various structural elements of the force-deformation characteristics were got. These rules shows the transmission path of the earth pressure between the two forms of supporting which is consistent with the previous theoretical analysis.