3D Numerical Simulation Of Cylindrical Foundation Pit

Circular retaining structure of cylindrical foundation pit is a reasonable structure. Due to its spatial arching effect, lateral displacement can be controlled within the very fine scope. In addition, because of the spatial symmetry of the cylindrical foundation pit, the earth pressure on the arch ring is balanced by itself. Retaining structure mainly bears hoop axial force. This compressive behavior of circular retaining structure can fully exert high compressive strength of concrete. Therefore, more and more cylindrical foundation pits are being applied in the actual engineering.Analysis is carried out by taking the rotational flow sedimentation tank for water treatment as an example. The software of FLAC was used to establish a model to simulate the displacement of the cylindrical deep foundation pit in different conditions. Analysis of earth pressure and displacement of the retaining structure is carried out. The comparison between the calculated and actual measured results is given. The result which is calculated by the numerical simulation and the calculated model can reflect the actual state very well. Validity of the model that is established by software is verified.The force and deformation properties of cylindrical foundation pit is analysed. The results shows that the main factors influencing the arching effect of cylindrical foundation pit are radius, elastic modulus of soils, inner friction angle of soils and thickness of retaining structures. Where, radius of the cylindrical is the main factor to influence the arching effect. The arching effect shows a nonlinear increase with decreasing radius of cylindrical of foundation pit.At last, by using FLAC3D software, numerical analysis is carried on the super deep excavation of the underground transformer substation for the world exposition of Shanghai 2010. Numerical simulation of lateral displacement and uplift deformation is carried out about retaining structure which is influenced by spatial arching effect. The results indicate that the displacement of retaining structure is relatively small, that because this engineering uses Inverse Method, the stiffness of floor slabs and supports is relatively big, moreover, the arching effect of the circular retaining structure give full play to reduce the lateral displacement.