A Nonlinear Numerical Simulation Of The Behavior Of PCCP In Soft Ground During Construction Process And Under Working Conditions

PCCP(Prestressed Concrete Cylinder Pipe) is a new progress of pipelinematerial in recent years, and is widely used in many water conveyance projects. Howevver, the acknowledge about its bearing mechanism and deformation properties remains unclear. Nowadays the theory research about PCCP is severe drop behind practice. In soft ground, the pipe's mechanical characteristics and deformation are more complex, especially with construction sequences, for this reason it is necessary and also important for the tracing analysis of the whole construction procedure. To the question, in this text we will simulate the PCCP in soft ground during construction process and under working conditions by nonlinear numerical analysis.In the firt place, the current situation concerning application of PCCP as well as direct shear test research of sand and gravel were presented. Then based on finite element analysis software Plaxis, this paper introduced the principle and method of finite element analysis. On the basis of experimental research and finite element analysis, much works has been done in this paper:1. The direct shear test about sand and gravel were carried out to obtain the index value of strength, which was concerned in the project. Through this test, some characteristics of deformation about cohesiveless soil were found. Finally based on the analyzing of shear test data, this paper got the index value of shearing strength.2. Two-dimensional nonlinear finite element models have been built to analyze the whole construction of PCCP. Then discussed the related factors of influence on construction according to the change of soil property,stiffness of pileline,gradient of excavation, interfacial roughness, thickness of gravel cushion.3. In this paper, two-dimensional finite element models have been built to simulate the repairing of double-pipe at normal operation stage.4. Through building three-dimensional finie element modles, parametric studies of two factors causing asymmetric settlement were conducted, considering soil property,stiffness of pipeline, stiffness of connection, thickness of gravel cushion. Conclusions were conducted in the end, which may be a reference for engineering practice.