The Mechanical Response And Applicability Of Pile Foundation In Nuclear Safety Hydraulic Structure

Nuclear safety class structure plays an important role on the safety of the nuclear plant. It is particularly sensitive to the uneven deformation of the basis. Usually the safety level structures builds on the rock foundation with good integrity and high strength, to ensure their safety and stability. However, for hydraulic corridor which the longitudinal length is far greater than the cross-sectional size, conditions of the foundation will inevitably exist uneven The traditional solution is to replace the soil with concrete from bedrock,however it is high cost, long construction period and the design is too conservative. Pile foundation is the main solution on the deep foundation. It is widely used in the railway, light rail and high rise buildings in the industrial and civil constructions. But at present, pile foundation has not been applied to the nuclear security level structures. This paper will discuss the applicability of the pile foundation in the nuclear safety level hydraulic corridor.Based on the ANSYS using numerical simulation, discussing the main factors such as site conditions, pile geometry size, arrangement that influence the reaction of the pile-soil-corridor system, this paper has done the static and the seismic time history analysis. There are the following conclusions:â‘ In the static situation, the deformation is small, soil elastic modulus is the most significant factors on the response of structures, but when The E is larger than 200 MPa, then good effect of increasing the E not obvious.â‘¡For the shallow buried bedrock, for horizontal earthquake analysis, it is proposed a simplified analysis model that concentrate the quality of corridor to the capitals of the pile, the result reveals that adding a beam in the middle is more effective than increasing the number of piles in the cross-section direction.â‘¢For the deep buried bedrock, using the method of equivalent sheet pile, it simplify three-dimensional model to two-dimensional plane strain model. With APDL programming, it successfully implements the viscous spring boundary and analysis the horizontal displacement of the pile with different mechanical parameters of soil and pile geometric. The conclusion is that the horizontal displacement of the pile can be the same value of the free field ground response.â‘£Using the results of free field analysis, apply the displacement to the pile body, and then obtain the internal forces to design the pile.