Numerical Simulation Of Planted Tube Method Construction And Parameter Sensitivity Analysis Based On Fluid Solid Coupling

In order to meet the cooling water requirements of nuclear power plants,the drainage tunnel,vertical tube and drainage head usually need to be built in deep water.And in the process of construction,the geological environment is complicated,the construction conditions are harsh and the personnel safety is difficult to guarantee.To improve engineering quality,ensure the safety,improve the efficiency and save time for the project,a new construction technique—“plant tube method” was proposed based on the existing drainage riser construction technology by Lufeng Nuclear Power Plant.And it will be a typical construction.However,the safety of some difficult processes in the technique needs to verify,and the influence of engineering parameters on construction quality also needs to study.This paper focuses on the problems above to research and obtains the following results.1.The construction schedule and the control points of “plant tube method” and “vertical lifting method” are briefly discussed.The feasibility of the two methods is studied by engineering analysis and empirical analysis.These two methods are compared based on project duration,project quality,construction control,anti-seepage treatment and engineering cost.In order to ensure the safety of construction,this paper has studied the construction process such as the planting of vertical tube,shield construction runs through the vertical tube,the process of vertical tube getting through to drainage tunnel.And a three-dimensional finite element model,which includes the three key processes,has been built considering fluid-solid coupling,and the material characteristic,load and the method of construction flow simulation has been studied.2.The whole construction process of “plant tube method” has been simulated.First,the process of vertical tube planting is simulated,observing the deformation characteristics and stress distribution of vertical tube and studying the relationship between the outer concrete protective layer and the stress deformation of the vertical tube.Second,the process of vertical tube getting through to drainage tunnel is simulated,the variation of settlement and gradient by soil loss and soil disturbance with cycle ruler of vertical tube is studied,and the distribution of pore water pressure and the selection of reasonable supporting force are also studied.Finally,the construction of the connection between drainage tunnel and drainage riser is simulated.The stress and deformation characteristics after cutting the segment ring and after the drainage riser chiseling the pedestal concrete is studied.3.A global sensitivity analysis method based on Morris method is put forward.First,Morris method is chose for global sensitivity analysis through the comparison of sensitivity analysis methods.Second,select density,elastic modulus,internal friction angle,cohesive force,permeability coefficient and void ratio to analysis the accuracy of drainage riser “planting” influenced by the excavation of drainage tunnels according to Morris method.Finally,through the statistical analysis of the calculation results,the conclusion is drawn: To the settlement of drainage riser,elastic modulus and internal friction angle are the most significant,and have obvious coupling effect with other parameters;To the gradient of drainage riser,elastic modulus,density and internal friction angle are the most significant,and elastic modulus and internal friction angle also have obvious coupling effect with other parameters.