| With more and more construction of highrise(super highrise) buildings, subway and other underground engineering, foundation ditch engineering became more and more widespread, and the depth became more and more deep. At the same time, types of the bracing structure are increasing and improving. For the new bracing structure spring up in practice, new theory should be established to guide it, so it is necessary to do theoretical analysis. Because of the deep excavation cause an extremely complex interaction between the surrounding soil and bracing structure, which makes it is very difficult for the internal force analysis of the foundation pit bracing system. At the same time, the complexity of the bracing system leads to the prototype test analysis considerable difficult. Therefore, it is meaningful to do simulation analysis of the foundation pit bracing system.The paper will analysis the application of shotcrete and anchor blot support and reinforced slope toe in a certain type of of soil. Through the finite element software Ansys finite element model is established, and the model considering the nonlinear of soil and the interaction between structure and soil. It also can simulate the process of pit excavation. When considered the nonlinear, the model was selected the D-P constitutive model. When considered the interaction between structure and soil, it was selected shear spring unit and the coupling between the units. It used"birth and death"units to achieve every step of the excavation and the exerting of shotcrete and anchor blot support structure. After finishing model, initial state which only had the initial stress but no initial displacement was simulated. Then it analyses the variation of the displacement and moment of side wall in the process of excavation, and the analysis contain the reinforced and without reinforced. Afterwards many contents about shotcrete and anchor blot support and reinforced slope toe was simulated. The main contents are as following:(1) simulating the variation of the displacement and moment of reinforced concrete wall in the process of excavation(2) the internal and external stability of bracing system influenced by anchor length and space(3) slope toe soil deformation influenced by composite reinforcement width and depth of the cement deep mixing pile(4) analyzing the load-carrying properties of cement-stabilized soil(5) the global stability analysis of abrupt slope after reinforceBased on the above content about supporting system analysis, find out the reasonable parameters of influence factors of bracing system. At the same time, through the analyzing of the load-carrying properties of cement-stabilized soil, find out the most dangerous place of foundation pit after reinforce. Finally, The overall stability was checked by comparing with Bishop simplified model theory.After completing the above model of finite element simulation, you need to verify the result through practical engineering in the present. But the supporting system of engineering has a few application in the practice. So the wall anchor and piled anchor support system model were used to indirect verify the model which is built here. And through the analysis of project case, the feasibility of the building model method was verified. |
