Finite Element Analysis Of Deformation Behavior On The Enclosure Structure Of Pits In Foundition Pit

Because of the need of basement features or the risistance of caps indifferent size inbasement foundation，or developingthe urban underground space and building the subwaystation at the same time，result in different depth of excavation，and then the secondary andmulti-stage excavation comes out—pit in pit． When people meet pits in foundation pit，theygenerally cared more about the stability and security of excavation when excavate to thebottom of outside pit，but often ignored the impact of the internal pit in pit to the entireperiphery foundation pit．However, the existing rules and norms did not mention designprinciples of the pits in foundation pit，and relevant research and literature are rarely refer to，so it is difficult to consider the effect of pit in pit on deformation of the periphery foundationpit．1、This paper aimed at a pits in foundation pit instance in Guangzhou，used the finiteelement analysis software MIDAS/GTS to build and analyze its three-dimensional finiteelement model，and discussed the effect of pit in pit on the periphery foundation pit indifferent influencing factors．The main contents are following：2、Introduced the basic theory related to foundation pit，including calculaton of waterand earth pressure， the destabilizing forms of excavation， the deformation forms andtime-space effect of excavation，the internal forcecalculatingmethod of excavation，the relatedfinite element theory of excavation， and three constitutive models of geotechnicalengineering：linear elastic model, nonlinear elastic model and elastic-plastic model．3、Numerical simulated the simplified model，analyzed the effect of pit in pit on theperiphery foundation pit in different factors such as the depth of the pit in pit，the distance ofthe inside and outside pit，soil properties，the supporting structure stiffness of pit in pit and thesupport forms of pit in pit and other external supporting structure of the pit．By analyzing theconclusions we can provide guidance for the engineering practice．4、Used MIDAS/GTS software create and analyze the three-dimensional finite elementmodel of a pits in foundation pit in Guangzhou，compared the calculation results with themonitoring result to verify the rationality and applicability of the three-dimensional finite element model．...