Research On Interaction Between Pile Anchor Supporting Structure Of Deep Excavation And Soil Body

The studies of pile anchor supporting structure of deep foundation pits have aroused the attention of scholars,and the collaboration research between supporting structure and soil still needs to be further researched.Among them,the interaction analysis of pre-stressed anchor and soil,the interaction analysis of pile and soil are more studied,and the studied of the interaction analysis of pile anchor supporting structure and soil still has not yet mature,also have no a reasonable,simple and practical,and is widely recognized method.Scholars studied from different angles on the pile anchor supporting structure,such as deformation coordination,the interaction of piles and soil's calculation model,the anchor's deformation,etc;But the study of these aspects are still many deficiencies,such as the establishment of the deformation compatibility condition,not considering the shortage of the anchor angle;On the calculation model of pile soil interaction is not considering the lack of thickness of the contact surface;And calculation method's deficiencies on the anchor 's deformation,etc.Based on the domestic and foreign achievements,in view of the above shortcomings,studied from the two aspects of theory analysis and numerical simulation,from the three aspects analyzed of supporting pile and soil mass,anchor and the interaction between the pile anchor supporting structure and soil,specific works are as follows:(1)On the basis of the principle of supporting pile and soil interaction,established a new calculation model of pile soil interaction,the model still formed spring element to simulate the pile soil;The difference is considering the influence elements on supporting pile to pile lateral soil deformation near some area,put forward the concept of contact area,and simulate pile lateral soil with series spring.After pile soil interaction model is established,through the boundary conditions,the finite difference method to calculate the internal force of pile body,and cited a typical project example,the numerical simulation using PLAXIS,illustrates the feasibility of this method.(2)Describing the basic principle of anchor reinforcement soil with infinitesimal body and node unit;Considering the displacement in the three-dimensional state of anchor and soil node,deriving displacement of bolt,and simplifies the calculation formula of anchor 's elongation;Put forward this equation can only be applied to bonding length of anchor bar,using iterative method to calculate the displacement of the bolt and surrounding rock,then calculate the axial force and shear force of anchor rod.(3)The pile anchor supporting structure and soil interaction system as the research objects,considering the combined action of soil resistance after the pile and anchor tensile,to establish the static equilibrium equation,on the basis of pile anchor deformation compatibility condition that summed up by predecessors,modified it,and compared with the other three algorithms of deformation compatibility condition,the results show that this improved method can reflect the actual situation of the pile anchor supporting structure deformation,which designed pulling force of anchor is more big than other methods of designed pulling force of anchor,this is because to overcome the aforesaid methods that ignore the anchors' obliquity,increasing the anchors' elongation and not considering the stress states of pile anchor.And combined with engineering example,using FLAC3 D to simulate the pile body's internal force and calculate the internal force of pile body by the modified method are basically consistent,illustrating the superiority of the improved method.