Based On The Fuzzy Comprehensive Evaluation Method Research Of Ultrasonic In Pile Testing

Pile foundation has a long history, the new is now widely used in various construction industry, is hidden engineering, quality and pile foundation directly determine the merits of the building, thus affecting the safety of people's life and property, testing and inspection of pile foundation is essential so. For the super long concrete piles, the need to detect pile bearing capacity and integrity. Pile integrity testing of a variety of methods, including the sound wave transmission method has the advantages of comprehensive testing, and the important representatives in pile test method, its application in the industry more, but the standard of evaluation is not comprehensive, and the bearing capacity of the pile foundation can not judge. Therefore, the need for further research and improvement.The paper studies the principle of sound wave transmission method, analysis of its principle and history of heart, were reviewed in detail between the different acoustics parameter and concrete quality of concrete, so as to establish the relationship between acoustic parameters and pile body flaw. Relationship between comprehensive discussion on the evaluation results of pile foundation detection data and the corresponding test data, determine the corresponding to different kind of defects is, focus on the evaluation method of the defect of pile body, pile foundation pile bearing performance corresponding to various defects, and the acoustic pipe slant correction problem. The research results show that, the pile foundation evaluation method of the existing single, usually with only one or two acoustic parameters of pile foundation for evaluation, cannot consider a variety of acoustic parameters of mutual common result to evaluate the quality of pile foundation, the performance also can only be determined by another test method of bearing pile.In order to enrich, improve evaluation methods for existing, this paper will put forward a new pile foundation quality evaluation method, at the same time on the pile bearing performance study of defects. First of all, this paper based on the finite element method theory, using the finite element software Midas GTS to simulate the defects of different pile pile, and simulate the same defect, so as to calculate the bearing capacity of pile foundation in different vertical location of defect. So find out the geologic condition of thick sand layer, the relationship between bearing capacity and various defects of super long bored pile; secondly, this paper uses the theory of fuzzy mathematics, the scientific method of fuzzy comprehensive evaluation method is proposed based on the original criteria, considering the value of acoustic parameters of the four interaction of sound velocity, amplitude, frequency and PSD, thus evaluation of the quality of pile foundation. Using the fuzzy comprehensive evaluation method to judge the quality of pile foundation, through the statistics of the "F" distribution method "to establish the evaluation index with respect to each trapezoid pile foundation evaluation and semi trapezoid membership function, then uses the fuzzy analytic hierarchy process to calculate the evaluation index of the objective, reasonable weight value of each measuring point, finally through fuzzy operation, get a comprehensive evaluation of the results.In order to validate the fuzzy comprehensive evaluation method is science and practicability, and superior to the original criterion, this paper has been through the analysis of a large number of engineering examples to verify. From this result, fuzzy comprehensive evaluation method is reasonable?scientific?feasible in this paper. Combine the fuzzy comprehensive evaluation method with the fuzzy analytic hierarchy process, the comprehensive consideration of several important acoustic parameters criterion, compared with other evaluation methods, the results of the method of multi evaluation is objective, more real, more perfect, and achieved good results.