Analysis Of Seismic Response Of Buried Prestressed Concrete Cylinder Pipe

Underground pipe are important to support social activities. Once they suffer an strong earthquake, it may bring serious influences on urban development and national political stability. The destinations of the south-to-north water diversion Beijing and Tianjin are both located in high intensity seismic belt. Therefore, the research on seismic design of prestressed concrete cylinder pipe has an important theoretical meaning and engineering value.The movement of underground structure under earthquake is results from the interaction between soil and the structure. Taking the soil-structure interaction as the core theory and the dynamic FEM theory as the analysis method, a interaction model for PCCP structure under earthquake is built based on the finite element software ANSYS. By detailed calculations, some rules on the response of the PCCP under different type of soil, depth of pipe, seismic frequency, Young's modulus of concrete, thickness of PCCP are summarized, which can provide reference to the seismic design of underground pipe. The main researches and conclusions are as follows:(1) The seismic responses of PCCP are analyzed using time history method. The focus is on the influence of horizontal width of 32 meter, 40 meter, 48 meter, 60 meter, 72 meter, 80 meter to seismic response of PCCP for several generally used artificial boundaries. The results show: the horizontal width should be larger than fifteen times of inner diameter of PCCP for all the test artificial boundaries. Viscous-spring boundary is a better one than other type of artificial boundaries in seismic analysis of underground pipe.(2) Based on the theorical method and research results above, the influences of type of soil, depth of pipe, seismic frequency, Young's modulus of concrete, thickness of PCCP on seismic responses of PCCP are discussed. The results show: The type of soil and seismic frequency have more impact on seismic responses of PCCP, and inner water pressure, and depth of pipe have weak impact on seismic responses of PCCP. The soil and pipe thickness can be selected to reduce the seismic response. Hard venues and appropriate thickness of pipe can reduce the stress and deformation.