Study On Fuzzy Random Reliability Of PC Pipe Piles

With its high-strength, good bending, shear resistance performance and wide range of application, prestressed concrete pipe pile is considered as an important type of piles and has been widely used in Wuhan area in recent years. However, the reliability of prestressed concrete piles has been seldom studied. In this thesis, the fuzzy random reliability of prestressed concrete pipe piles has been studied. Moreover, the fuzzy comprehensive evaluation of the choice of ground treatment schemes has been analyzed.The theory of structural reliability used in civil engineering is briefly introduced. However,original variables are most likely to be correlated in the reliability analysis of geotechnical engineering and several methods of reliability index calculation are discussed. The basic concepts of fuzzy mathematics have also been introduced. The present state of application of fuzzy mathematics in geotechnical engineering field has been introduced as well.By analyzing fuzzy random reliability of test results of prestressed concrete pipe piles in Wuhan area, the evaluation method of prestressed concrete pipe piles failure is proposed. At first, considering the randomness and fuzziness of the failure of pile, the settlement rate of pile is taken as a fuzzy random variable by using related theory of fuzzy mathematics. The membership function is determined by fuzzy statistical analysis of 42 static load tests of prestressed concrete pipe piles in Wuhan area. The probability formula and the calculation method of reliability index are derived by assuming the probability distribution of settlement rate and using the probability theory of fuzzy event. At last, based on the practical project, it is proved that taking pile failure as randomness and fuzziness is reasonable. It can provide reference for the judgment of failure of pestressed concrete pipe piles in engineering practice.The uncertainty problems in the choice of ground treatment scheme have been analyzed by fuzzy comprehensive evaluation. The modeling and analysis method are introduced. The application of fuzzy comprehensive evaluation method in the ground treatment scheme is discussed. The selection of action factors, establishment of membership function and the determination of weighted coefficients are emphatically analyzed.