Structural Research On Large-scale Underground Reinforced Concrete Bifurcation

With the development of the Hydropower Engineering, more and more large-scale underground reinforced concrete bifurcations have been applied. These structures usually have the properties such as hign internal water pressure, hign external water pressure, and large diameter, etc. For the complexity of the loads on bifurcation, there are many difficult problems in research on the stability of surrounding rock and the design of lining.The status of the research on underground reinforced concrete bifurcation has been introduced in this paper. Subsequently, the theory and method of FEM have been stated, and the numerical simulate method of ground stress and seepage flow field have also been provided. In accordance with the loads-bearing characteristic of underground reinforced concrete bifurcation, the analysis model and simulate method of the elasto-plastic materials such as surrounding rock and lining have been presented by using the FEM analysis software ANSYS.In accordance with the practice of a pumped storage station's reinforced concrete bifurcation, the 3D nonlinear FEM analysis of the structure have been carried out on different working conditions such as construction, operation and examination. The stability state of surrounding rock and the stress-strain of lining are analysed. Based on the two design theories for water pressure, namely surface pressure and seepage pressure, different simulate models have been put forward so as to study the stress-strain of the lining, the stress of rebar and the state of crack. Some beneficial conclusions have been obtained and the results have some reference value for other similar projects.