The Research On Application Of Ultrasonic Transmission Method For Testing Bored Piles

With distinctive technical characteristics, ultrasonic transmission method currently is a reliable method to test concrete quality of bored piles and gets a wide range of applications in construction of highways and bridges, etc. Although it is a relatively mature technology, there are still problems in practical application and further research is needed.Basing on the practice of testing piles of bridges, the thesis is intended to carry out corresponding research into the application of ultrasonic transmission method. The existing norms use the threshold value to evaluate the quality of piles with sound velocity and amplitude as evaluation parameters, but it often causes conflicting results in testing. So the thesis introduces the method of fuzzy mathematics and establishes the comprehensive evaluation model with waveform incorporated into the system of evaluation, developed the current evaluation method in order to make evaluation results more all-sided, reliable and rational. Through the statistics, analysis and research of vast testing data, the scatter-gram of sound velocity of piles and relationship curve of sound velocity-range are obtained, and the different trend of sound velocity-range between pile and structure concrete is discovered with its reasons analyzed as well. The simulating curve considering factors, which influences it, dovetails nicely with the actual trend of sound velocity-range of piles. The different defects of bored piles have different acoustic characters. With the related data and testing practice, the thesis summarizes the acoustic characters of some defects and initially establishes corresponding relationship between the acoustic parameters and types of defects. When the super-long broken pile of a bridge across strait is treated, the ultrasonic transmission method is employed to monitor the whole process of treatment to grasp whether the defect is influenced by treatment, and guarantees the successful treatment of the pile.That opens up a new application field of ultrasonic transmission method. As the slant or distortion of detector tubes and the defects of concrete quality will cause abnormal change of acoustic parameters, the thesis summarizes the differences between them and analyzes the relation between sound velocity and the age of concrete.